April 2009 

NASA/TM-2009-215713 

NESC-RP-04-10/03-004-E 

 

Mars Exploration Rover Flight Operations 

Technical Consultation 

Dave S. Leckrone/NESC 

Goddard Space Flight Center, Greenbelt, Maryland 

Cynthia H. Null/NESC 

Ames Research Center, Moffett Field, California 

John Caldwell 

Brooks Air Force Base, Brooks-City Base, Texas 

Claude Graves 

Johnson Space Center, Houston, Texas 

Dean A. Kontinos/NESC 

Ames Research Center, Moffett Field, California 
NASA STI Program . . . in Profile

 Since its founding, NASA has been dedicated to 

the advancement of aeronautics and space science. 

The NASA scientific and technical information (STI) 

program plays a key part in helping NASA maintain 

this important role. 

 The NASA STI program operates under the 

auspices of the Agency Chief Information Officer. It 

collects, organizes, provides for archiving, and 

disseminates NASA’s STI. The NASA STI program 

provides access to the NASA Aeronautics and Space 

Database and its public interface, the NASA Technical 

Report Server, thus providing one of the largest 

collections of aeronautical and space science STI in 

the world. Results are published in both non-NASA 

channels and by NASA in the NASA STI Report 

Series, which includes the following report types: 

• TECHNICAL PUBLICATION. Reports of 

completed research or a major significant phase 

of research that present the results of NASA 

programs and include extensive data or 

theoretical analysis. Includes compilations of 

significant scientific and technical data and 

information deemed to be of continuing 

reference value. NASA counterpart of peerreviewed formal professional papers, but having 

less stringent limitations on manuscript length 

and extent of graphic presentations. 

• TECHNICAL MEMORANDUM. Scientific 

and technical findings that are preliminary or of 

specialized interest, e.g., quick release reports, 

working papers, and bibliographies that contain 

minimal annotation. Does not contain extensive 

analysis. 

• CONTRACTOR REPORT. Scientific and 

technical findings by NASA-sponsored 

contractors and grantees. 

• CONFERENCE PUBLICATION. Collected 

papers from scientific and technical 

conferences, symposia, seminars, or other 

meetings sponsored or co-sponsored by NASA. 

• SPECIAL PUBLICATION. Scientific, 

technical, or historical information from NASA 

programs, projects, and missions, often 

concerned with subjects having substantial 

public interest. 

• TECHNICAL TRANSLATION. Englishlanguage translations of foreign scientific and 

technical material pertinent to NASA’s mission. 

 Specialized services also include creating custom 

thesauri, building customized databases, and 

organizing and publishing research results. 

 For more information about the NASA STI 

program, see the following: 

• Access the NASA STI program home page at 

http://www.sti.nasa.gov

• E-mail your question via the Internet to 

help@sti.nasa.gov

• Fax your question to the NASA STI Help Desk 

at 443-757-5803 

• Phone the NASA STI Help Desk at 

443-757-5802 

• Write to: 

 NASA STI Help Desk 

 NASA Center for AeroSpace Information 

 7115 Standard Drive 

 Hanover, MD 21076-1320
National Aeronautics and 

Space Administration 

Langley Research Center 

Hampton, Virginia 23681-2199 

 

April 2009 

NASA/TM-2009-215713 

NESC-RP-04-10/03-004-E 

 

Mars Exploration Rover Flight Operations 

Technical Consultation 

Dave S. Leckrone/NESC 

Goddard Space Flight Center, Greenbelt, Maryland 

Cynthia H. Null/NESC 

Ames Research Center, Moffett Field, California 

John Caldwell 

Brooks Air Force Base, Brooks-City Base, Texas 

Claude Graves 

Johnson Space Center, Houston, Texas 

Dean A. Kontinos/NESC 

Ames Research Center, Moffett Field, California 
Available from: 

NASA Center for AeroSpace Information 

7115 Standard Drive 

Hanover, MD 21076-1320 

443-757-5802 

The use of trademarks or names of manufacturers in the report is for accurate reporting and does not 

constitute an official endorsement, either expressed or implied, of such products or manufacturers by the 

National Aeronautics and Space Administration. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

1 of 47 

NESC Position Paper 

Request Number #: 03-004-E

Requestor Name: Matt Landano (JPL) Requestor Contact Info: (818)-354-5624 

Short Title: Mars Exploration Rover (MER) Flight Operations 

Description: NESC Human Factors experts to participate in pre-landing MER Operations 

Readiness Review; NESC Flight Sciences experts to serve on MER Entry, Descent and 

Landing Red Team 

Date Received: 09-23-03 Date Consultation Initiated: 12-03-03 

Lead Assigned: Dr. Dave Leckrone Lead Contact Info: (301)-286-5975 

Date Consultation Concluded: 03-26-04 

Background:

The Mars Exploration Rover (MER) Project at the Jet Propulsion Laboratory developed 

two golf-cart size robotic vehicles, Spirit and Opportunity, for geological exploration of 

designated target areas on the surface of Mars. The primary scientific objective of these 

missions was the search for evidence of the presence of water on or near the surface of 

the planet during its history. Spirit and Opportunity were launched on June 10 and July 7, 

2003, with their respective landings scheduled for January 4 and January 25, 2004 

(UTC). NASA views the MER missions as particularly critical because of their scientific 

importance in the ongoing search for conditions under which life might have existed 

elsewhere in the solar system, because of their high level of public interest and because 

more than half of all prior missions launched to Mars internationally have failed. 

The development, flight operations and surface operations of the two MER vehicles 

presented many challenges to the JPL Project, two of which motivated requests for NESC 

consultations – the critical entry, descent and landing (EDL) phase of flight operations, 

and Human Factors associated with ground operations of the vehicles after landing. The 

EDL phase consisted of a complex sequence of autonomously commanded events 

intended to decelerate the MER from approximately 12,000 mph to a soft touchdown 

over the course of approximately 6 minutes. The sequence begins with direct entry from 

its interplanetary trajectory, with the aero-shell’s heat shield reaching a maximum 

temperature of 2637 degrees F. This is followed by deployment of a braking parachute 

and heat shield jettison; separation of the Lander vehicle from the back shell, with the 

Lander descending on a tether or bridle; inflation of the airbags needed to provide a soft 

and protected landing of the MER vehicle cocooned within; firing of three solid retro 

rockets bringing the Lander to zero vertical velocity approximately 40 feet off the 

Martian surface; cutting of the bridle, allowing the Lander to free fall to the surface; and 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

2 of 47 

multiple bounces of the airbags across the Martian surface with the Lander ultimately 

rolling to a stop. A “Reconstruction” Team within the JPL MER Project was assigned the 

task of piecing together the EDL performance of Spirit with the intent of recommending 

any needed modifications to the sequence for Opportunity, to enhance its chances of a 

successful landing. As an additional risk-reducing measure, an independent EDL “Red 

Team”, comprised of independent outside experts was assigned the task of monitoring 

and assessing the reconstruction activities of the Project team. 

After landing, each MER had a nominal prime mission period of 90 days, with the 

possibility of subsequent mission extension for as long as the vehicles’ batteries and other 

subsystems remained viable. The MER ground control team consisted of engineering 

personnel responsible for the safe and successful operation of the Spirit and Opportunity 

vehicles and instruments on a 24 hour-per-day basis. In parallel, teams of scientific 

investigators developed and maintained the exploration strategy that informed operational 

commanding of the two MER’s. Vehicle operations were closely coupled to the 

availability of sunlight on the Martian surface needed for re-charging batteries and to the 

schedules of communication opportunities. Consequently, ground operations were tightly 

locked to the Martian rotation period or day (called a “Sol”), approximately 40 minutes 

longer than an Earth day in duration. Work shifts of 10-12 hours (or occasionally longer) 

continuously slipped in start and stop time by 40 minutes per Earth day. Thus, the effects 

of long work shifts in a high-pressure environment were exacerbated by the progressive 

loss of synchronism with the patterns of daily life outside the JPL control center. The 

potential for operator error resulting from fatigue or stress under these demanding 

circumstances, as well as concerns about the health of the operations staff, motivated the 

MER Project to seek remedies to minimize the risk and to optimize team performance. 

Request to NESC for Technical Consultations: 

In September 2003 the NESC Chief Engineer at JPL forwarded requests to the NESC 

Board for technical experts in the areas of Flight Sciences (Entry, Descent and Landing) 

and Human Factors to participate in the MER review processes at JPL. Formally, under 

NESC procedures, this was a request for “Technical Consultation.” The NESC Director 

designated the NESC Chief Scientist to take the lead in coordinating this consultation. 

The Chief Scientist requested support from the NASA Discipline Expert (NDE) for Flight 

Sciences and the NDE for Human Factors. In addition the NESC Chief Engineer at ARC 

suggested the possibility of Flight Sciences support from that center. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

3 of 47 

The following experts were identified as leading authorities with the requisite experience 

in these disciplines and they agreed to serve on the MER Technical Consultation Team: 

Human Factors: Dr. Cynthia Null, ARC 

 Dr. John Caldwell, USAF, Brooks Air Force Base 

Flight Sciences: Mr. Claude Graves, JSC 

 Dr. Dean Kontinos, ARC. 

Brief biographies of these individuals are provided in Appendix A. 

Dr. Null and Dr. Caldwell participated in the MER Operations Readiness Review (ORR), 

December 3-4, 2003. Their findings and recommendations were included in the ORR 

Board report to JPL management and are documented in their individual reports provided 

in Appendices B and C, respectively. Dr. Null paid a follow-up visit to JPL on March 3, 

2004 to assess how the ORR recommendations had been implemented. Appendix B 

includes a summary of her observations from that visit. 

 

Mr. Graves attended the MER Project Operational Readiness Test, December 6-9, 2003, 

to observe firsthand a simulation of the MER landing and the EDL process and 

procedures. The independent EDL Red Team convened at JPL to witness Spirit’s entry, 

descent and landing on January 4, 2004, and met each day thereafter through January 8, 

to assess the EDL reconstruction activities in the MER Project Reconstruction Team’s 

“war room”. The Project Reconstruction Team divided itself into sub-teams focusing on 

specific aspects of EDL. The Red Team assigned one or more of its members to each of 

these sub-teams. Mr. Graves worked with the Entry Dynamics sub-team, while Dr. 

Kontinos was assigned to Descent Dynamics, Deployments and Separations. The full Red 

Team convened daily to observe the full Reconstruction Team tag-up meetings. Mr. 

Graves and Dr. Kontinos fully participated on the Red Team and contributed to its final 

report to JPL management. Appendices D and E, respectively, reproduce their individual 

reports. Appendix F provides the Red Team final report in its entirety. 

The following sections summarize and discuss the findings and recommendations of the 

NESC MER Consultation Team in these two areas. 

Findings and Recommendations:

1. Finding: There is inadequate awareness within the Agency of established 

standards regarding acceptable workload and fatigue mitigation. Little leverage 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

4 of 47 

currently exists to apply such standards to individuals or groups who are not 

NASA employees or contractors. 

Recommendation: NASA should implement and assure the work time limits 

for critical operations across the Agency as outlined in NASA Procedural 

Requirement 1800.1. Means should be found to apply such standards to all 

parties, whose performance is important to mission success, even those not 

employed by NASA or its contractors. 

2. Finding: Lack of in situ measurements of atmospheric properties actually 

encountered during entry and descent forces the EDL Reconstruction Team to 

rely on assumptions and inferences in diagnosing potentially serious deviations 

from expected vehicle performance. 

Recommendation: We strongly recommend that pressure and temperature 

sensors (or some form of an atmospheric data system) be carried on the 

spacecraft in all future missions that include EDL and that do not have an 

independent method for acquiring critical in situ atmospheric parameters. 

3. Finding: The overall EDL reconstruction process is not well documented, 

making it very difficult for an oversight group such as the Red Team to penetrate 

and assess. 

Recommendation: The EDL technical processes, as well as the processes and 

schedules for required output products and key decisions, should be well 

documented in a form that is usable by independent experts. 

4. Finding: The occurrence of higher than expected angle-of-attack and largeamplitude oscillations of the entry vehicle below Mach 6 have not been explained. 

NESC Recommendation: Follow-up investigation to ascertain the causes of 

dynamic instability and high angle-of-attack is important for future 

planetary missions and should be pursued by JPL. The results of this 

investigation should formally be reported in a widely available professional 

publication. The NESC Flight Sciences Super Problem Resolution Team 

should review and assess the results. 

5. Finding: Specific displays and software tools would strengthen the 

reconstruction teams’ ability to properly understand EDL events and to draw valid 

conclusions and make recommendations in a timely manner. 

Recommendation: JPL should provide to the Reconstruction Teams for 

future EDL’s software tools to visually display multiple variables on the EDL 

timeline and to perform automated frequency decomposition of the data. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

5 of 47 

Human Factors Discussion:

The MER Project clearly recognized the importance of Human Factors in creating the 

environment necessary for mission success. The Project, working with the Fatigue 

Countermeasures Group at Ames Research Center, took a number of steps in the years 

and months leading up to the ORR to address the potential problems. These included: 

incorporating in the operations staffing plan the provision for a 4-days-on/3-days-off 

schedule for staff working 10-12 hour shifts; providing on-site napping facilities for use 

in situations where personnel must remain at JPL for excessively long duty periods; 

providing sleeping quarters at a nearby hotel for individuals who might be too fatigued to 

drive home; providing on-site food, medical and other services at the “odd” times 

dictated by the work schedule linked to Martian time; providing training to managers and 

staff members regarding causes, potential consequences and amelioration of fatigue; 

making special housing arrangements off-site for members of the science teams to 

provide relative isolation from sleep-disrupting factors. And watches that keep Martian 

time were supplied to staff members. 

The assessment by the NESC Human Factors experts noted several areas in which 

mission preparations could be improved. There was a general impression that the MER 

leadership might be underestimating the potential consequences of fatigue to personnel 

safety and effectiveness. In particular there was a concern that the leadership might place 

too much faith in their own ability to monitor the fatigue level of individuals and to gauge 

accurately the extent to which staff fatigue was threatening day-to-day mission execution. 

There appeared to be no “hard-and-fast” rules limiting the number of hours per day or the 

maximum number of days per week or per month beyond which personnel simply would 

not be allowed to work. At the time of the ORR, neither the MER Project, nor the NESC 

Human Factors experts were aware of the relatively new NASA Procedural Requirement 

NPR 1800.1 (October 16, 2002), pages 202-209, that sets objective criteria for maximum 

durations of work before a break is required. Consequently, there were no formalized 

procedures in place for identifying when the workload on individual employees or groups 

had become so excessive as to constitute a threat to mission success, nor plans for safely 

handling unavoidable increases in workload. The fatigue training offered for all MER 

staff members was apparently made optional. Although the impulse against mandatory 

training is understandable, it does disregard the fact that improperly managed fatigue has 

been identified as a causative factor in several high-profile disasters, including the 

Challenger mishap. No provision had been made for frequent, independent assessments 

of fatigue levels in MER personnel beyond simply relying on the subjective judgment of 

the team leaders, who may themselves be overly fatigued or whose judgment may be 

swayed by other considerations (e.g. availability of critical individuals, avoiding 

unanticipated staffing shortfalls, etc.). Stress and fatigue issues were likely to emerge 

even prior to surface operations with last-minute pressures to resolve sequence 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

6 of 47 

development and testing problems. It was not clear to the NESC experts that the prior 

experience with the Mars Pathfinder mission, that surface operations would entail a 

decreased workload and would be less stressful than development, was as applicable as 

MER managers believed. Significant development work and system “de-bugging” 

remained to be done in the weeks leading up to EDL and Impact-to-Egress, and the 

associated stresses could readily carry over into the surface operations phase. 

The follow-up visit to JPL by Dr. Null in February produced an important observation 

about stress and fatigue of the members of the science teams. Although MER Project 

management was able to implement work limits (10-12 hour days, 4 days work followed 

by 3 days off) for the civil servant and contractor staff members responsible for the 

operational safety and performance of the MER vehicles on Mars, little leverage existed 

to require the science teams to pay attention to their own fatigue levels. The Opportunity 

Science Team was “worked to the bone” to prepare for a press conference in Washington, 

D.C. on March 2. The scientists who flew to the east coast to appear at the press 

conference apparently resumed work almost immediately upon returning to JPL without 

much of a break. Members of the Spirit Science Team who were interviewed admitted to 

being exhausted, but were unwilling to leave their work. This is cause for concern. 

Although the science teams had no direct operational responsibility for the “health and 

safety” of the rover vehicles, they were responsible for defining on a day-by-day basis the 

scientific strategy that guided mission operations. Such decisions must be made with 

clear heads. Poor judgment and poor decisions arising from fatigue could have a direct 

bearing on the scientific success and value returned from the missions. 

The NESC Human Factors experts made three specific recommendations as a result of 

the ORR. These were incorporated into the ORR Board findings and recommendations 

that were submitted to JPL management. The JPL response to each is indicated. 

1. Appoint an independent flight surgeon to evaluate on a regular basis the fatigue 

status of all team members. Although JPL elected not to recruit an “outside” flight 

surgeon, they did appoint the resident physician of JPL’s Safety Organization and 

Medical Services, Dr. Robert Estrada, to take on this role. Dr. Estrada effectively set 

up a comprehensive health and fatigue plan, including educational posters, visitation 

schedules and other prevention activities. 

2. Create alternative methods to get exhausted workers home. In response, JPL 

worked creatively to provide additional support to protect exhausted team members. 

Access to taxi’s or hotel rooms was made available and publicized to MER team 

members. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

7 of 47 

3. Establish maximum work limits and mandatory breaks from work. As 

discussed above, civil service and contractor operations personnel more or less 

followed the pre-defined work schedule, except during anomalous events. The 

scientific teams apparently did not follow such a prudent schedule. 

Flight Sciences (Entry, Descent and Landing) Discussion:

The EDL Red Team was asked specifically to address three questions in regard to their 

oversight of the Project Reconstruction Team’s work: 

1. Did they have the correct data and use it properly?

2. Did they identify the correct issues and work them in the correct priority? 

3. Did they use the correct processes in doing their work?

The NESC representatives provided answers to these questions that reflected the 

consensus of the Red Team as a whole. Briefly stated, the Project team used the available 

data very effectively and supplemented the data with ground testing of selected hardware. 

The team sought corroboration when possible, e.g. comparing accelerometer and gyro 

data or comparing IMU’s on rover and backshell. When no direct comparison was 

possible, they sought plausibility or consistency between different data sets. Key issues 

were identified promptly and appropriately prioritized. JPL assigned the highest priority 

within the Center to Spirit post-flight assessment and surface system operations. Key 

personnel, test hardware and facilities were made available to augment the EDL 

reconstruction process, including resources outside of JPL (e.g. at LaRC). There is no 

evidence that any important issues were overlooked. The overall reconstruction process 

however, was not well documented and thus was not completely clear to the members of 

the Red Team. In particular the process and schedule for making decisions regarding 

Opportunity’s up-coming EDL was not apparent. Nevertheless, the Project 

Reconstruction Team worked very well as a cohesive unit. The team members clearly 

understood what needed to be done and day-to-day activities progressed very well toward 

achieving the team’s objectives. Cooperation with the Red Team was excellent; the Red 

Team had timely access to available data and status of assessments. 

A number of technical issues arose regarding system performance of Spirit during EDL 

and regarding the adequacy of data available on the ground to inform the decisionmaking process about what steps should be taken for Opportunity’s EDL. A complete list 

is given on page 4 of the Red Team’s final report (Appendix F). Two issues of particular 

concern to the NESC representatives, identified during reconstruction and re-emphasized 

after both rovers had successfully landed, are discussed below. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

8 of 47 

1. The reconstruction of the atmospheric density profile was based on accelerometer 

measurements and the assumption that the aerodynamic characteristics of the 

aeroshell were nominal. The reconstructed density was lower prior to parachute 

deployment and higher after parachute deployment than had been predicted on the 

basis of the atmospheric model used. Apparently, as a consequence of the initial 

low-density encounter, parachute deployment time, triggered at a specified 

dynamic pressure of 725 Pa, was later in time and at a lower altitude 

(approximately 2-sigma) than expected. Although this reduced the time margins 

to complete descent and landing to a low level, as measured by the parachute 

deployment altitude, margin was regained because the parachute descended more 

slowly than expected. The cause of this fortuitous “over-performance” of the 

parachute was not understood. Had relatively simple pressure and temperature 

sensors been included on the spacecraft for use during terminal descent and after 

landing, the physical situation actually encountered in situ during Spirit’s EDL 

would have been much clearer to the reconstruction team. The relative 

contributions of errors in the density profile model versus possible errors in drag 

coefficient could have been accurately assessed. As it was, the reconstruction 

team had to rely on assumptions and inferences in attempting to diagnose 

significant deviations from expected performance that had the potential for 

serious consequences for mission success. 

2. The aerodynamic performance of the entry vehicle did not conform to 

expectations from 175 thru 251 seconds after entry, just prior to parachute 

deployment. The angle-of-attack, while still well within safe margins, was higher 

than expected at flight conditions below Mach 6, with large-amplitude 

oscillations. Prior to entry there was an expectation of a dynamic instability when 

the vehicle decelerated to around Mach 3. The entry data showed that potentially 

this instability occurred as high as Mach 6. An instability occurring at a higher 

Mach number has a longer time to grow and hence can cause greater dispersions 

in attitude. The aerodynamic model used may be inadequate or incorrect, in the 

regime between Mach 6 and approximately Mach 3. The NESC representatives 

have emphasized that it is important for future planetary exploration missions to 

determine the cause of such instabilities. We are assured by the MER EDL Chief 

Engineer at JPL that this issue is under investigation at JPL. We do recommend 

that the results of the JPL study be published for the broader community to 

review, such as in an AIAA paper. 

As a result of the Spirit EDL reconstruction activities, both the JPL reconstruction team 

and the EDL Red Team made the same recommendations to JPL management regarding 

modifications of Opportunity’s EDL profile. These included a recommendation to not 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

9 of 47 

change the entry flight path angle, but to increase the dynamic pressure at parachute 

deployment by 25 Pa as to increase the time margins on the parachute system. 

The NESC representatives and the Red Team as a whole recommended several areas of 

potential process improvement for future flights with similar EDL’s occurring in a short 

period of time. A software tool should be developed to visually display the EDL timeline. 

Multiple variables could be plotted and displayed simultaneously as a function of 

trajectory variables. In this way a more comprehensive and integrated view of the EDL 

sequence could be communicated. Secondly, a capability for automated frequency 

decomposition of the data would also improve the process. Frequency analysis by “eyeballing” may be sufficient for dominant modes, but it does not reveal power in other parts 

of the spectrum. Stacking up multiple data traces, denoting EDL events, and showing 

frequency content would be a powerful analytical approach. 

Conclusions: The MER expeditions have been outstanding successes, significantly 

exceeding original expectations both in terms of technical performance and scientific 

return. The MER Project at JPL and its broad support network performed with a very 

high level of dedication and competency. The Project and JPL are to be commended for 

their exemplary work and wonderful achievements. The broad national span of the NESC 

allowed us to bring together experts of the highest caliber from other NASA centers and 

from the U.S. Air Force to provide assistance and oversight in specific technical and 

scientific disciplines to the MER Project. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

10 of 47 

APPENDICES 

A. Biographical sketches of NESC representatives 

B. Human Factors report from Dr. Null 

C. Human Factors report from Dr. Caldwell 

D. EDL reconstruction report from Mr. Graves 

E. EDL reconstruction report from Dr. Kontinos 

F. EDL reconstruction Red Team final report 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

11 of 47 

APPENDIX A 

Biographical Sketches 

Cynthia Null: 

Before being detailed to the NASA Engineering and Safety Center as a Discipline Chief 

Engineer for Human Factors, Dr. Cynthia H. Null was a scientist in the Human Factors 

Division and Deputy Program Manager of the Space Human Factors Engineering Project. 

She began her career at NASA Ames in 1991 as a branch chief in the Human Factors 

Research Division. In 1996, she edited the Space Human Factor Requirements Definition 

for the Advance Human Support Technology Program. In 1997 while a program manager 

in the Aeronautics Enterprise, Dr. Null was part of the lead team designing the Aviation 

Safety Program and was the Ames Deputy Manager to the AvSP Program Office at 

Langley from 1997 until 1999. She was the acting Chief of the Human Factors Research 

Division from Spring of 1998 until she returned to research in late 1999. She teaches a 

course in Human Center Design for Aerospace Engineers at Stanford University. 

Dr. Null received a BA in Mathematics from Albion College, and an MA and Ph.D. in 

Quantitative Psychology from Michigan State University. Her career began with an 

academic appointment at the College of William and Mary, where she was on the faculty 

for 18 years before joining NASA. She has been the managing editor of the journal 

Psychometrika since 1984. 

John Caldwell:

John Caldwell obtained his Master's degree in Experimental Psychology in 1979, his 

Ph.D. in Experimental Psychology in 1984, and his Pilot's Certificate in 1985. During his 

16 years with the U.S. Army's Medical Research and Materiel Command, he served as 

Chief of the Crew Stress and Workload Branch for 5 years before spending 10 years as 

the lead scientist over Aviation Sustained-Operations research at the U.S. Army's 

Aeromedical Research Laboratory. He has conducted numerous aviation performance 

studies in specially-instrumented simulators and aircraft. He has been a senior consultant 

to the Fatigue Countermeasures Group at the NASA Ames Research Center. Presently, 

and he is currently the Principal Research Psychologist for the U.S. Air Force's 

Warfighter Fatigue Countermeasures Program. He has published numerous peerreviewed articles in scientific journals such as Psychopharmacology, Aviation, Space, 

and Environmental Medicine, Military Psychology, and Aviation Psychology; as well as 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

12 of 47 

"user-focused" papers in operationally-oriented periodicals such as United Airlines'

Safetyliner, the Airline Pilots Association International's Centerline, Delta Airline's

FlightLine, the U.S. Air Force Air Combat Command's Combat Edge, the U.S. Air Force 

Safety Center's Flying Safety, the German Forces Flight Safety publication

Wehrmedizinishe Monatsschrift, and the U.S. Army's Army Aviation. He has authored 

book chapters on The use of stimulants to counter sleep deprivation and Sleep problems 

in aviation personnel, and he recently coauthored a book entitled Fatigue in Aviation: A 

Guide to Staying Awake at the Stick. He is an internationally-recognized expert in fatigue 

management in aviation continuous and sustained operations, and he is a member of the 

Speakers Bureau for the National Sleep Foundation's Drive Alert, Arrive Alive campaign. 

He frequently presents papers and provides fatigue-management workshops at scientific 

conferences and elsewhere. In addition, he offers instructional support for flight surgeons, 

commanders, and unit aviation personnel. 

Claude Graves:

Mr. Graves is an internationally recognized expert in 

atmospheric entry design, analysis, and guidance. He is largely responsible 

for Shuttle entry trajectory and guidance design, as well as intimately 

familiar with Apollo, Gemini, and several planetary entry flight designs. 

In addition, he currently is involved as a lead at the Johnson Space Center for entry, descent, 

landing, and/or aerocapture for multiple planetary projects, such as the '07 

Mars Phoenix Lander and the '09 Mars Science Laboratory. 

Dean Kontinos:

Dr. Kontinos’ career has focused on the development and application of 

computational methods for the design of thermal protection systems for hypersonic 

vehicles. He has developed computational methods for simulating fluid flow and 

heat transfer. He has also been active in developing procedures for incorporating 

high fidelity computations in the design process. He currently is Chief of the 

Reacting Flow Environments Branch at the Ames Research Center, where he is 

managing activities in computational analysis, entry vehicle design, and high 

enthalpy ground testing. Dr. Kontinos received his Ph.D. in Aerospace Engineering 

from North Carolina State University, Raleigh in 1994. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

13 of 47 

APPENDIX B 

Mars Exploration Rover Operations Readiness Review 

3-5 December 2003 

Human Factors Risk Assessment and Recommendations 

Cynthia H. Null, PhD 

NESC Human Factors Discipline Expert 

The two major categories of human performance that apply to understanding of risk to 

this mission are human fatigue and countermeasures, and operational procedures and 

interfaces. 

1. Human Fatigue and Countermeasures 

 

The effects of Mars’ time on the staff have been recognized by the MER leadership. 

They have been proactive, working with the Fatigue and Countermeasures Team from 

Ames Research Center. The project has taken many actions to protect their staff. These 

actions include: optional training in fatigue and countermeasures, staffing plans, nap 

room, room darkening shades in work areas, easy access to food during night shifts, and 

Mars local time watches. The project has directed the team leads to protect their staff by 

watching for signs of fatigue and recommending when a fatigue countermeasure (such as 

a nap, or ending a shift early) needs to be used. In addition, I believe that arrangements 

have been made to offer transportation home for overly tried staff. The project leadership 

has noted the time critical aspects of Entry-Descent-and-Landing phase (EDL) and the 

Impact-to-Egress. It is recognized that the operations of two vehicles simultaneously will 

add pressure and workload to certain staff. 

 

Other observations: There are no maximum duty standards or procedures to identify how 

much work is “too much work” or an objective measure of fatigue used by the project. 

Although the staff plan for this project after EDL for most operations entails a 4-dayson/3-days-off schedule, already several people are scheduled to work 10 consecutive 

days, 10-12 hour shifts. 

There is a belief, based on the “Pathfinder” experience, that surface operations will have 

decreased workload and will be less stressful than development. However, the program 

readily admits that they are not ready to operate the rovers and the science instruments. 

At the last PORT, the sequence development was not successful 2 out of 5 days. This 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

14 of 47 

means that development of surface mobility and science operations tools will be 

proceeding during operations by the same team of people. As long as the tools are 

immature, it is not rational to believe workload will decrease. 

Evaluation of fatigue issues is left to the subjective judgment of the team leads or for the 

person to recognize that they personally are dangerously overworked. The team leads 

may have difficulty making this judgment especially when there is schedule pressure-- 

when the people are needed to achieve for mission success. Both human limitations in 

self- evaluation and the needs of the mission, will limit a person from making the “I am 

overworked” judgment in a timely manner. Additionally, it is not clear who is looking 

after the team leads. 

The number of tasks that need to be accomplished by all teams in the next 3 weeks 

appears to be extensive, so the planned break before the EDL and ITE may evaporate. If 

the break disappears, the project needs to be especially attentive to human error during 

procedure execution. 

Although there was much sensitivity expressed that personal requirements will arrive at 

inconvenient times, I heard of no provisions to aid the JPL staff. 

Recommendations: 

A. Set objective criterion, after decisions with the ARC Fatigue and Countermeasures 

team, for maximum hours of work before a required break or an alternative objective 

measure of fatigue. 

B. Appoint an independent flight surgeon to evaluate the fatigue and health status of all 

project staff on an ongoing basis. There are two important criteria for this person: (1) 

experience in operational evaluations of fatigue and (2) someone the staff can trust. I 

believe that a military flight surgeon experienced in dealing with fatigue issues during 

long field operations could be a great help. 

C. Appoint a concierge to handle personal requirements that arise in conflict with 

mission schedule, to reduce the stress on the JPL staff. Note, such a person has been 

identified to assist the university scientists. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

15 of 47 

2. Operational Procedures and Interfaces. 

The timing and the structure of the review did not allow for evaluation of this important 

aspect of operations. For surface operations, the team is relying on the belief that the 

rover can not be harmed by inappropriate sequences—that is, its fail-safe features will 

protect the rover. I did not see a proof of this fail-safe capability—which is a concern. If 

this assumption is correct, the failure of procedures and interfaces could impact science 

data return but will not jeopardize the mission. However, the proof seems to be not a 

proof but a good feeling that the rovers are safe because they rejected sequences. This 

only indicates that some of the time incorrect sequences will be recognized. First time 

event procedures need to be followed carefully and sequences verified before they are 

uploaded to the rovers. 

From looking at high stress, high workload operations in other domains, one would easily 

conclude that the most important time to be diligent about safety and mission anomalies 

is when there is no time. Do not allow mission schedule and operational pressures to 

reduce normal reporting of incidents, unexpected outcomes, and off-nominal events, such 

as ISAs. When tasks are most complicated and schedules tight, and there is no time to 

document issues, the most important thing to do is document. 

Lessons learned: 

From other domains we can conclude the including human factors expertise during the 

development of operational procedures and interfaces can reduce workload and enhance 

the quality and error tolerant nature of the procedures. 

Evaluation of procedures and interfaces can be done during a PORT, but it is difficult or 

impossible to do in a formal review, as an ORR. 

Recommendation: 

D. Do not reduce requirements for documentation of incidents, unexpected 

outcomes, lessons learned and off-nominal events. Provide support to teams, for 

example an extra person without mission operations responsibilities to be 

responsible for such documentation. Make sure information gets provided to the 

teams operating Spirit and Opportunity. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

16 of 47 

Notes From Follow-Up Human Factors Visit To JPL/MER 

Cynthia Null 

March 6, 2004 

Frank Mortelliti arranged my visit to the MER team. 

Robert R. Estrada, Medical team lead, began the day with an upbeat briefing on how his 

office was working with the MER program to mitigate the risk that human fatigue can 

have on mission success though prevention and training. Prior to the MER ORR, the 

Ames Fatigue Countermeasures Group provided workshops for MER managers and team 

member on fatigue and sleep management. The JPL EAP published a resource guide for 

team members and their families. Posters on the recognition and management of fatigue 

were posted throughout MER work areas. 

Dr. Estrada described visits by the doctors that take place on Thursday nights and Friday 

mornings. I believe every team is visited approximately two times in every three weeks. 

The medical visits are informal – walking around and being available. Safety does a 

separate walk-around. I did not get the idea that either the doctors or safety would be 

unwilling just to say everyone needs a day off—let’s just skip the next SOL. 

It was not clear if any MER team members had taken advantage of nap rooms, or hotel 

rooms, or cabs home. 

Richard Cook, MER Program Manager, joined our discussions. He appeared to be fluent 

in sleep/duty concerns. 

There have been three events that have obviously put a lot of pressures on certain teams. 

 1. Evaluation of EDL between Spirit and Opportunity landings, with the Red team—

where margins were not understood 

 2. Spirit airbag not retracting, requiring extra days to get off the landing craft, and 

the need to do a pirouette and alternate route exit—something they tried very hard to 

avoid. 

 3. Spirit flash memory and rebooting problem—Cook said is that this was not a 

major technical problem, but the press put a lot of pressure on the team. ”They all knew 

they would solve this quickly.” 

 

It appears that no special effort was made to check up on the teams during these times, 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

17 of 47 

when fatigue risk was very high. I was given the impression that everyone switched to 

“right stuff” mode and worked until issues were resolved. One of the issues brought up in 

general discussions at the ORR was the fact that for most technical positions there was 

little depth on the teams—that is only one or two people with skills, knowledge and/or 

training. This lack of team depth (redundancy) will be most apparent during off-nominal 

events. 

From Frank Mortelliti, “You’ll recall, the worst phase was ITE for Spirit when a lot of 

intense problem-solving required long hours of work. Since then, shifts have shortened to 

8-10 hours and, as Henry Stone says, ‘we’re getting better at what we do...it takes less 

time now.’ “ 

More recently, I would guess that the Opportunity Science team was worked to the bone, 

to prepare for the March 2 press conference. Leaks were happening, the science team did 

not want to be scooped, they needed to get everything lined up, and part of the team 

needed to get to the East Coast. At least two of the people I saw on TV on noon on 

Tuesday PST from DC, were seen at the lab before 2 pm Wednesday. Hopefully they had 

slept the entire weekend before their “15 minutes of fame”. 

After the informal discussions with Dr. Estrada, Richard Cook, and Frank Mortelliti, I 

was allowed to talk privately with anyone who was available, though there was some 

pressure to keep moving. I talked to 4 persons involved in sequencing and mission 

control. They all had slightly different stories to tell—not surprising. One person 

described how management had been helpful in adjusting work schedules to 

accommodate a family emergency. MER team members also admitted that in the 

beginning they were coming in on their days off, so they wouldn’t miss anything. They 

were all aware of fatigue and sleep management issues. 

 I spent most of my time visiting with the Spirit Science team—their work schedule fit 

best into the timing of my visit. I saw science subteams that appeared to be working well 

together. The individuals I talked to, in general, admitted to being exhausted and 

unwilling to leave. I believe from a staffing view the science teams had little 

redundancy, so everyone needed (or felt the need) to work as much as possible. Even 

those who were apparently not exhausted said that the science teams did not work the 4 

days on, 3 days off schedules of operations. One scientist said that in the beginning he 

worked science for both rovers—since science teams work overnight SOLs and the 

rovers are 12 hours apart—this sounds like 24 hours to me. I talked to others who 

worked sequencing or up/down-link on their four days on, and then worked science on 

their three days off—this will involve a time shift of 8-10 hours at the beginning and end 

of each “3 days off” and results in no time off. I did see cots in offices that look used. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

18 of 47 

I discussed work schedules for scientists with Safety, Dr. Estrada, and Richard Cook. 

They all agreed that the scientists were working whatever hours they wished. They said 

that this was individual choice—like not wearing a bicycle helmet (my analogy). They 

stated that this could be the only time in their career for these scientists to get this type of 

data, therefore this was all that mattered to the scientists and working was their choice. At 

least one person said, they [the scientists] are not in mission critical positions (I took that 

to mean since they were not controlling the rovers directly so they could not harm the 

missions). 

 In our discussions of the possibility of setting duty limits, I was told that this 

could/would only be for critical personnel. I assume that referred to mission managers, 

since they make the key decisions. Most of these people work Earth time. It was stated 

that the limits needed to be sensitive to the mission design—not just the science of sleep 

and circadian rhythms. It seems that the MER management team believes they have 

enough safeguards on the rovers so that incorrect instructions to the rover will be rejected 

by the rover. That is, they are operating under the belief that operations could NOT flip 

over a rover or run a rover off a cliff. Everyone was reluctant to even discuss duty limits 

(although by setting work schedule to 10-12 hours 4 days on, 3 days off—they have 

essentially done this.) 

During my visit, I just saw tired scientists who were unwilling to go home, or even take a 

nap. I suppose they needed to make sure the data they cared most about would be 

collected on the next SOL. I saw people that seemed to be just fine—looked like normal 

scientists during a normal day—intense, animated, involved, etc. But even if scientists 

can’t jeopardize the mission, long- term sleep loss has a variety of very negative effects 

including reduced immune function, short temper, lack of judgment, lack of selfawareness and so forth. 

I asked for some data on use of hotels and taxis by JPL staff. 

When I was at JPL, the MER team was looking toward an extended mission. The intention 

would be to work two approximately 10 hour shifts synchronized to Earth time, which 

would make things easier on sequencing and mission control teams. They do not have the 

final plan worked out. I also have no idea how the science teams would handle this. It 

would mean robotic tasks and data approximately every other day, although I don’t quite 

understand how that works, with uplink/downlinks and Mars daylight. They have asked 

Ames Fatigue group to help with this re-planning. 

The MER team has taken a variety of proactive steps to assist team members in working 

Mars time. Dr. Estrada and this team have stepped in to provide a variety of services. In a 

main, it appears that these activities have been successful for the mission operations and 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

19 of 47 

sequencing teams. I remain concerned that the scientists are ignoring much of the advice 

provided on managing fatigue and sleep, and this has been accepted by JPL. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

20 of 47 

APPENDIX C 

Mars Exploration Rover Operations Readiness Review 

Workload Fatigue Risk Assessment and Recommendations 

John Caldwell, Ph.D. 

NASA Engineering and Safety Center/U.S. Air Force Research Laboratory 

1. On 3-5 December 2003, a Mars Exploration Rover (MER) Operations Readiness 

Review (ORR) was conduced in the Building 167 Conference Room at Jet Propulsion 

Laboratory (JEP), Pasedena, CA. As a Review Board member representing the NASA 

Engineering and Safety Center, the following observations/recommendations are offered 

based upon the material presented by MER personnel: 

a. Observations on the positive side: Although the majority of the briefing 

content was focused more on “engineering issues” rather than “human performance 

concerns,” it was clear that issues of personnel workload and the fatigue from shift work 

and extended duty periods were of importance to the MER staff. Most noticeably, the 

project leadership has noted that the time-critical work to be accomplished prior to the 

rapidly-approaching Entry-Descent-and-Landing phase (EDL) and the Impact-to-Egress 

phase along with the probable (but as yet unknown) requirements to handle unexpected 

events, etc. will likely place a great deal of strain on the teams responsible for ensuring 

success in these areas. In addition, there was recognition of the fact that the workload 

required for handling Surface Operations on the currently-planned schedule for a 3-

month period certainly would be daunting given current staffing levels. Furthermore, 

MER personnel had given thought to the circadian-adaptation problems posed by the 

necessity to continuously rotate work schedules by 40 minutes per day in order to 

accomplish tasks on a time schedule corresponding to the Mars day (as opposed to the 

Earth day). The MER leadership should be commended for considering these issues and 

for working with members of the Fatigue Countermeasures Group at NASA Ames 

Research Center to understand and address many of the known fatigue-related concerns. 

Specifically, it was noted that the following provisions have been made: 

1). In light of the fact that 10-12 hour work shifts have been deemed necessary, 

the overall staffing plan for most operations entails a 4-days-on/3-days-off schedule to 

attenuate a dangerous escalation in cumulative crew fatigue throughout the mission (this 

is particularly the case for Surface Operations). 

2). To help mitigate excessive fatigue in situations where personnel must remain 

at JPL for excessively-long duty periods, napping facilities have been provided on site. 

3). To prevent overly-fatigued personnel from placing themselves at risk for a 

drowsy-driving mishap, arrangements are in place to provide sleeping quarters on site or 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

21 of 47 

at a nearby hotel. In addition, I believe there was a provision to offer transportation home 

for fatigued individuals. 

4). JPL has ensured that necessary services (i.e., food, medical, etc.) will be 

provided to MER personnel despite the fact that such services will be required at odd 

times according to a typical Earth-day schedule. 

5). As a general preventative measure, the MER staff provided training to 

managers and staff members on the causes of operator fatigue, the potential consequences 

of improperly-managed fatigue, and the scientifically-valid strategies for countering 

fatigue during the course of the mission. 

6). In very general terms, the Ames Fatigue Countermeasures Group was 

apparently consulted on crew scheduling issues, although it appears that they were not 

fully involved in the development of optimal staff schedules. 

7). For the science teams, JPL has arranged for off-center housing that will help to 

facilitate operator sleep (and subsequent alertness) during MER shift-work operations. 

Examples of special considerations include: a) securing “blocks” of apartments so that 

the shift workers will be living in relative isolation from sleep-disrupting factors, b) 

making arrangements for housekeeping services to be performed on a shift-work-friendly 

schedule, and c) preparing rooms outfitted with blackout curtains. 

b. Observations on the negative side: Despite the recognition that human fatigue 

will almost certainly be a consideration during every phase of the MER mission, most of 

the MER leadership seems to be underestimating its potential impact on crew safety and 

effectiveness. In addition, the leadership is, in my opinion, placing far too much faith in 

their own ability to monitor the fatigue levels of staff members and to accurately gauge 

the extent to which staff fatigue is threatening day-to-day mission readiness. The 

following specific problems were noted: 

1). Despite the existence of staffing planes, there appear to be no “hard-and-fast 

rules” about maximum working periods (hours per day) or maximum consecutive duty 

periods (days per week or month) beyond which personnel simply will not be allowed to 

work. 

2). Since there are no stated maximums, there also are no formalized procedures 

for identifying how much work is “too much work” for any given employee or group, and 

how (and whether) an unavoidable increase in workload requirement will be safely 

handled. 

3). Although fatigue training was offered for all MER staff members, this training 

was apparently made optional despite the fact that improperly-managed fatigue is a 

known threat to operational safety and effectiveness (and has in-fact been identified as a 

causative or contributing factor in several very high-profile disasters such as the 

Challenger mishap for instance). 

4). There is no mechanism or provision for an on-going “fatigue assessment” of 

MER personnel beyond simply relying upon the subjective judgments of the team leaders 

(who may end up being overly-fatigued themselves, and/or who may be susceptible to 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

22 of 47 

unintentionally ignoring the presence of undesirable fatigue levels in favor of maintaining 

a high staffing profile). 

c. Recommendations: At this late stage of the game, it may not be feasible to 

develop and validate formal duty-limitation plans and procedures. Also, there probably is 

insufficient time to formulate a workable set of procedure that can be implemented to 

temporarily safely exceed the published limitations (given that specific fatigue 

countermeasures are implemented). Both of these tasks would require extensive 

coordination among MER leaders and the fatigue experts at NASA Ames (or elsewhere). 

Finally, it may also be too late to schedule make-up fatigue training sessions for 

managers who elected not to attend the earlier sessions provided by Ames personnel. 

However, there are a couple of recommendations that would immediately provide a 

substantial reduction in the fatigue risk: 

1). An operationally-experienced NASA or Air Force (or Army) flight surgeon 

should be immediately assigned to monitor all phases of MER operations, and to 

perform face-to-face subjective fatigue assessments of staff members on a routine 

basis (i.e., several times per week). Care should be taken to recruit/assign a seniorlevel flight surgeon who has had considerable experience working within the context 

of demanding NASA space missions (in the case that a NASA flight surgeon is 

chosen) or within the context of demanding military missions in which sustained 

operations were required (in the case that an Army or Air Force flight surgeon is 

chosen). This flight surgeon should be completely independent of the existing MER 

leadership, and if possible even independent of the onsite JPL leadership. His/her 

decisions about the status of individual staff members and actions to ensure the 

safety, alertness, and effectiveness of these staff members must be binding. It is 

highly recommended that the assigned flight surgeon be required to coordinate fully 

with an on-site fatigue expert from Ames (or the Air Force) since considerable 

expertise in this particular area is crucial. 

2). Since it is clear that there will be several relatively short periods of time (i.e. 

9-10 days) in which the operational pace will reach unusually high levels, and since an 

experienced flight surgeon will be on site to oversee various fatigue 

treatment/countermeasure options, it is strongly recommended that a policy allowing the 

use of pharmacological fatigue adjuncts be immediately developed and implemented. 

-Pharmacological adjuncts should include, at a minimum, sleep-inducing 

agents to maximize the restorative value of crew napping opportunities. The 

primary agents that should be considered for this purpose are zolpidem (Ambien) 

and zaleplon (Sonata), both of which have been shown to safely and reliably 

induce sleep without producing unwanted residual effects upon awakening. 

These agents will enable effective napping even when the naps are unavoidably 

placed at periods of time where restful sleep will be difficult to obtain. Research 

has shown that naps induced with these agents ultimately enhance subsequent 

performance due to improved sleep quality. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

23 of 47 

-Pharmacological sleep-inducing agents also should be available to help 

promote and maintain the daytime sleep of MER shift workers, especially for the 

first 2-3 days of a shift rotation. One excellent agent for this purpose is 

temazepam (Restoril) which has been shown to enhance the quality of 6- to 8-

hour non-standard sleep periods. The use of temazepam as a daytime sleep 

enhancer has been shown to enhance subsequent performance. 

-For limited periods of time during which nap/sleep opportunities are 

virtually nonexistent due to extremely high work demands, some consideration 

should be given to developing a policy and plan permitting the short-term use of 

alertness-promoting compounds. Of course, caffeine in the form of beverages, 

candies, and/or caffeinated gum should be considered first. However, modafinil 

(Provigil) also should be made available for flight surgeon prescription on a 

limited and controlled basis. Modafinil was recently FDA approved for the 

treatment of on-the-job sleepiness associated with shift work—a problem that will 

certainly be experienced by many members of MER operations. Modafinil also 

was just approved for use in certain types of Air Force flight operations. Both 

caffeine and modafinil have been proven safe and effective by military and other 

research organizations. 

Such adjuncts should not be used as a replacement for well-planned and well-executed 

work/rest schedules. They also should not be utilized until after non-pharmacological 

fatigue countermeasures have been exhausted. 

 3). In order to reinforce the fatigue-countermeasures training that has already 

been offered and to provide an opportunity for MER staff members to address specific 

problems that arise as a function of the ongoing mission schedule, brief refresher courses 

in fatigue countermeasures should be offered. Short refresher courses should be planned 

at least at the midpoint of surface operations, and the courses should be offered at a 

variety of times so as to minimize interference with the work schedule. These courses 

should be conducted by the NASA Ames Fatigue Countermeasures Group and/or the Air 

Force Research Laboratory (AFRL) Fatigue Countermeasures Branch in coordination 

with Ames. 

2. In summary, it appears that the MER project already has made significant 

strides towards proactively addressing the risks associated with the fatigue that will no 

doubt stem from extended duty periods and circadian misalignment. The MER team 

should be commended for their considerable efforts in this regard. However, there 

remains a degree of complacency regarding the insidious effects of fatigue that should be 

aggressively attacked. To further mitigate the likelihood that crew fatigue will adversely 

impact MER operations (all phases), continuous on-site flight-surgeon support should be 

immediately arranged, flight-surgeon decisions should be made in concert with experts 

from NASA Ames, a pharmacological fatigue-mitigation plan should be developed and 

implemented for acute high-workload and transitional periods, and refresher fatigue-
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

24 of 47 

countermeasures training should be scheduled at least at the midpoint of surface 

operations. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

25 of 47 

APPENDIX D 

MER RED TEAM REPORT 1 

January 6, 2004 

Claude Graves 

General Comments: 

• Overall the Mars Approach and the Spirit Entry, Descent, and Landing (EDL) for 

the Spirit spacecraft was very successful with the EDL systems performing well. 

• Based on a recommendation of the EDL Red Team during PORT 10 in 

December, 2003 the EDL reconstruction team implemented a chart that summarizes 

the key EDL events along with the limiting values, expected values, and estimated 

actual values. This was used during the remainder of the PORT 10 simulation and 

is being used by the Spirit reconstruction team. This has improved the 

reconstruction process and has been very useful tool to improve the help coordinate 

the reconstruction process and to provide visibility into the reconstruction status. 

• The reconstruction team is developing a plan for completion of the remaining 

work. This will be helpful in understanding the overall reconstruction status. 

• The reconstruction is incomplete with very little, if any, high frequency data 

received at this time so the reconstruction is preliminary and with some changes 

possible as the reconstruction progresses. 

• The reconstruction team will begin assessment of the changes needed, if any, for 

the Opportunity EDL. 

 

Specific Comments: 

• The approach trajectory control was very accurate resulting in deletion of the last 

planned Trajectory Control Maneuver (TCM) and the later contingency TCM 

opportunity. The entry flight path angle is estimated to be -11.494 plus or minus 

0.01 deg compared to a target value of -11.5 plus or minus 0.12 deg 3 sigma. 

• The key entry parameters are presently reported to be near expected values. 

• The atmospheric density profile deviated from the expected density profile with 

the reconstructed density profile estimated to be about 85 % of the expected density 

at about 25 km altitude. This density deviation was lower at bother higher and 

lower altitudes within the sensible atmosphere. The atmosphere experts have not 

endorsed this reconstructed profile The reconstructed density profile is based on 

accelerometer measurements and an assumption that the aerodynamic 

characteristics are nominal. 

• The parachute system was deployed based on an in-flight computation that 

ensures that the parachute is not deployed until the dynamic pressure has reduced to 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

26 of 47 

an acceptable value. This deployment logic worked very well and resulted in the 

parachute being deployed very near the nominal dynamic pressure with an actual 

deployment at 729 Pa vs. planned 725 Pa. The deployment time was later than 

expected was probably caused by the atmospheric variations discussed earlier. The 

resulting peak aerodynamic load on the parachute was estimated to be 11725 vs. 

13880 planned. 

• The parachute inflation time appear to be about as expected with an estimated 

inflation time of 1.33 to 1.58 sec compared to a nominal time of 1.3 sec. 

• The delayed parachute deployment reduced the time margins to complete the 

descent and landing, as measured by the parachute deployment altitude, to a low 

level. However, slower descent while on the parachute resulted in comfortable 

margins for completing the descent and landing. The cause of this slower descent 

while on the parachutes is not fully understood at this time. 

• The system that estimates the spacecraft translation speed relative to the Mars 

surface while on the parachute successfully determined the relative speed. This 

information was used to compute the propulsive maneuver needed to reduce the 

translation speed to protect the air bag system during the landing. The resulting 

horizontal relative speed at bridle cut was about 11.5 m/s compared to a limit of 21 

m/s. 

• The system to compute the horizontal relative speed uses photographs taken in 

sequence to estimate the relative speed. One of the photograph comparisons was 

deleted because the filter limits on the crater ridge definition was exceeded. 

However, the relative speed was successfully computed using the remaining 

information. 

• The bridle cut altitude was lower than expected and the altitude rate at bridle cut 

was higher than expected. 

• The landing loads were lower than the allowable, 8 to 10 g’s vs. a limit of 40 g’s. 

• The landing point is estimated to be about 9 km from the target and about 12 km 

from the pre EDL estimated mean landing point. 

Planning for Opportunity: 

• There are three items to be investigated to see if changes should be made for 

Opportunity: 

o Increase the time margins for terminal descent 

• Reduce entry flight path angle 

• Increase the dynamic pressure at parachute deployment 

• Change the post parachute deployment time line 

o Increase bridle cut altitude 

o Change the Dimes filter parameters to allow for a less clear definition of 

crater ridge 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

27 of 47 

MER RED TEAM REPORT 2 

January 16, 2004 

Claude Graves 

Specific Comments: 

One addition needs to be made to the specific comments about the Spirit EDL 

reconstruction and assessment defined in the MER RED TEAM REPORT by Claude 

Graves on January 6, 2004. The angle-of-attack was outside the expected bounds for 

speeds below about Mach 6 with large amplitude oscillations, but was within acceptable 

limits by a considerable margin. Potential causes of exceeding the expected bounds of 

the angle-of-attack were identified but the specific cause was not isolated. Initial 

examining the effect of retargeting to a shallower entry flight path angle using the 

potential causes of the large angle-of-attack showed a small degradation of the angle-ofattack envelope. This was one reason for not retargeting the entry flight path angle to 

increase the time on the parachutes. 

Changes for Opportunity: 

The Red Team was asked about the changes recommended for Opportunity EDL and the 

team recommended not changing the entry flight path angle because of the Spirit EDL. 

There could be subsequent changes to the entry flight path angle targeting if weather 

conditions along the entry flight path change based on real time atmospheric 

measurements. The Red Team did recommend increasing the dynamic pressure at 

parachute deployment by 25 Pa. to increase the time margins on the parachute system. 

The EDL reconstruction and assessment team made the same recommendations to the 

MER Project management and these recommendations were taken to the JPL 

management. 

It is interesting that the Red Team was asked to make a recommendation for Opportunity 

changes before the EDL team was asked. I do not believe this influenced the EDL team 

recommendation, but both groups concurred on the recommendations. 

MER RED TEAM REPORT 3 

January 23, 2004 

Claude Graves 

Recommendations for improvement 

The following recommendations for improvement are recommended for future flights 

with similar EDL’s occurring in a short period of time. In some cases the 

recommendations may apply to independent missions that include EDL. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

28 of 47 

• Include sufficient time and resources in the project plan to allow for development and 

demonstration of a rapid capability to complete the needed trajectory and systems 

reconstruction and assessment to affect the later EDL. 

• Include pressure and temperature sensors on the spacecraft for use during terminal 

descent and after landing. This information is necessary to be able to differentiate 

between atmospheric density and drag coefficient effects. This applies for all future 

missions that include EDL and do not have an independent method for acquiring this 

information.. 

• Enhance the display of flight data to allow use of multiple independent variables such 

as time, energy, and speed and include the ability to superimpose mission events. 

MER Spirit EDL Reconstruction and Development Assessment 

January 12, 2004 

Claude Graves 

EDL Team Assessment 

General Comments: 

The EDL reconstruction and development team is well qualified, motivated, and has an 

appropriate set of tools to accomplish their objectives. The activities are much better 

coordinated than during PORT 10. I was impressed with the quality and quantity of work 

as well as the cooperation among the team members and with the EDL RED Team. 

Effective use of data: 

The team has utilized the available data very effectively and has some conducted ground 

test of selected hardware to supplement the flight data to help understand some of the 

concerns. The data was properly assessed and provided to support the decision process 

for MER B. 

Identification of the correct issues and working in the correct priority: 

As expected the schedule is very tight and data availability was affected by data 

transmission needed to operate the surface systems. The team has promptly identified the 

correct key issues and appropriately prioritized the work effort to best use the resources 

in preparation for a timely decision for any changes needed for MER B. JPL assigned the 

post flight assessment and surface system operations of the MER A the highest priority 

within the Center and made available key personnel and test hardware and facilities to 

augment the EDL reconstruction and development. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

29 of 47 

The correct process: 

While the EDL Red Team would have preferred to have better insight into the overall 

process at the beginning of this effort the day-to-day activities progressed very well 

toward achieving the team objectives. Daily assignments were clear and effective with 

appropriate groups being formed for issues that involve multiple work areas. The EDL 

Red Team was accepted by the EDL reconstruction and development team as a partner in 

the process with the Red Team having timely access to available data and status of the 

assessments and with Red Team inputs included into the decision process. 

Decisions: 

The EDL reconstruction and development team made the correct recommendations to the 

management Teams. 

1 Flight Mechanics Team 

The Flight Mechanics team is also well qualified, motivated, and had an appropriate set 

of tools. The data was used properly with cross checks on the validity of the data where 

this is possible. The key issues were identified and the work was properly prioritized. 

Key resources at LaRC were effectively used to address identified issues. Although a 

process for this work was not documented the process worked smoothly with the correct 

interfaces and teaming arrangements developed to effectively complete the reconstruction 

and development activities. The team members were very cooperative and respectful 

within the team and outside the team and appropriately incorporated the EDL Red Team 

it their activities. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

30 of 47 

APPENDIX E 

Report to NESC, 1/16/04 

MER EDL Red Team , 1/3/04-1/9/04 

Dean Kontinos 

This report documents my participation as a member of the Mars Entry Rover (MER) 

Entry-Descent-Landing (EDL) Red Team. The Red Team was commissioned by the JPL 

Deputy Center Director to act as an independent group evaluating the data and process 

used by the MER EDL team to reconstruct the MER-A EDL sequence, and potential 

modification to the MER-B entry. 

The Red Team was chaired by Glenn Cunningham, independent consultant and retired 

JPL manager, and comprised of Bobby Braun, Georgia Tech; Gentry Lee, JPL; Dankai 

Liu. JPL; Bob Mase, JPL; Carl Peterson, Sandia National Labs; Dave Spencer, JPL; Sam 

Thurman, JPL; Jeff Umland, JPL; and Gordon Wood, consultant. In addition were 2 

NESC representatives: myself and Claude Graves, JSC. I took the place of Charles Smith, 

ARC, who was an original member of the team. 

The Read Team was asked three specific questions by the JPL Deputy Center Director. In 

addition, the Red Team was asked by the MER Project Manager to state a position 

regarding modification to the MER-B flight path angle. 

I provided a written report to the Red Team Chairman containing my answers to the three 

questions. I also provided comments and suggestions on process enhancement. The 

entirety of my report to the Red Team Chairman is contained herein. 

In summary, the Red Team recommended that no change be made to the MER-B entry 

flight path angle. This recommendation was unanimous within the Red Team and 

consistent with the EDL Team recommendation. A follow-on recommendation was to 

increase the parachute deploy dynamic pressure by 25 Pa. There was unanimity within 

the Red Team for this follow-on recommendation. The parachute deploy dynamic 

pressure issue is still being investigated by the MER program. Details of the rationale of 

the Red Team recommendations are documented by the Chairman and can be provided to 

the NESC upon request. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

31 of 47 

MER EDL Red Team , 1/3/04-1/9/04 

Final Report, 1/12/04 

Dean Kontinos 

This report contains my observations and findings as member of the MER EDL Red 

Team. The review period is 1/3/04 to 1/9/04, which covers MER-A entry, MER-A 

reconstruction, and MER-B EDL TCM decision. 

Before answering the specific questions that defined the objective and scope of the Red 

Team, a few comments on the quality and character of the EDL Team is appropriate. In 

my view, the EDL team was exceptional in both the technical capacity of the individual 

members and their professional interaction as a group. As individuals, the members were 

extremely knowledgeable, diligent, and enthusiastic. As a group, they were respectful to 

each other, tolerant of opposing views, and allowed time for everybody to be heard. 

There was an expectation of excellence while at the same time a willingness to support 

each other. This group dynamic, whether natural or learned over time, seemed to be an 

innate part of their group dynamic since there was little intervention by leaders to enforce 

group etiquette. Rather, the group was self-policing. Equally important was that members 

of the group challenged each other. Members were sufficiently broad in technical depth 

to question the engineer in charge of another area. The atmosphere was such that one’s 

data and analysis was questioned, but not the individual’s technical authority. Finally, 

there was an extraordinary amount of work performed during the week by associated JPL 

and LaRC personnel. Every day there was presented an analysis or test performed by an 

unheralded engineering working through the night. 

Did they use the data properly? 

The EDL Team did a great job extracting as much information as possible from the 

available data. The team sought corroboration when possible, e.g. comparing 

accelerometer and gyro data or comparing IMUs on rover and backshell. When no direct 

comparison of engineering data was possible, they sought plausibility or consistency 

between different data sets. In other words, if an event was postulated based on one type 

of data, consistency was sought with a different type. There always was somebody to 

argue the counter-point to every proposed theory. This process mitigated excessive 

speculation or extrapolation. 

2 Did they identify the correct issues and work them in the correct priority? 

The issues they did identify were definitely important. The EDL timeline margin was 

paramount because of the impending proposed TCM. Team priorities were set based on 

relevance to the TCM decision. I was not able to identify other issues that weren’t 

covered by the team that I thought were a priority. Perhaps we all overlooked something. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

32 of 47 

3 Did they use the correct process in doing their work? 

I was a late edition to the Red Team, had not participated in the previous PORT, and 

therefore was minimally prepared for Red Team duties. Perhaps this lack of preparation 

was the primary reason that the EDL reconstruction process was not clear to me. It 

seemed like there was an unspoken, undocumented, unadvertised process in the collective 

heads of the team. The team all seemed on the same page, yet I was confused much of the 

time regarding the direction of the team. More specifically, I understood the individual 

activities, but the process and schedule for making a MER-B decision was not always 

apparent. The only firm conclusion I can draw is that the process was definitely not 

documented. 

Along the lines of the previous point, it might have been useful to step through the 

decision logic prior to final resolution of the data. In other words, “what-if” thinking 

regarding the outcome of particular analyses could have been performed. For example, 

what if there is or is not convergence between the reconstructed atmosphere and the 

atmosphere model? How would the opposite results of that analysis affect the decision 

process? This type of thinking would serve to focus the team on the key issues as well as 

highlight the key data that actually affect the decision. I’m not advocating endless 

hypothetical speculation, but a little forward thinking. 

A key issue facing the EDL team was a 2-sigma late parachute deploy time. After 

atmosphere reconstruction, it was stated that a combination of 1-sigma dispersions on 

atmospheric density, winds, and drag coefficient are sufficient to cause a 2-sigma event 

in the chute deploy. This analysis is key because it supports the contention that the EDL 

systems behaved as they should, and that the unusual 2-sigma chute deploy event was the 

result of an unlikely combination of flight circumstances. The sufficiency of the 

combination of 1-sigma circumstance to cause the 2-sigma event was stated, but no data 

or analysis was ever shown. I’m not doubting the veracity of the analyst, only noting that 

a presentation of the data was not given. 

If ever a back-to-back entry is to be executed in the future, I have 2 recommendations for 

process improvement. The first improvement is a development of a software tool to 

visually display the EDL timeline. Multiple variables could be plotted and displayed 

simultaneously as a function of trajectory variables. For example, it would have been 

useful to see the accelerometer data plotted as a function of time along with entry speed, 

Mach number and altitude. EDL events could also be noted on the timeline. A simple 

switch would then permit plotting of the variables as a function of altitude, for example. 

In this way, a more comprehensive and integrated view of the EDL sequence could be 

communicated. The second improvement is automated frequency decomposition of the 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

33 of 47 

data. Several times I witnessed a frequency analysis by “eye-balling” the data. Although 

eyeballing is sufficient for the dominant modes, it does not reveal power in other parts of 

the spectrum. Stacking up multiple data traces, denoting EDL events, and showing 

frequency content would be a powerful analysis approach. 

The final observation regards the use of the Red Team itself. During the final meeting 

regarding the TCM decision, the project manager polled the Red Team for their opinion 

before the EDL team had unequivocally stated their recommendation. It seems in the end 

that the decision was not particularly controversial, nevertheless, the engineering team 

should be issuing their recommendation without influence from the Red Team. 

Report to NESC, Addendum, 3/26/04 

MER EDL Red Team , 1/3/04-1/9/04 

Dean Kontinos 

On 1/16/04, I had submitted a report to the NESC describing my participation on the 

MER EDL Red Team. The report contained some preliminary remarks describing the 

objectives of the Red Team, and then contained my submittal (in its entirety) to the Red 

Team Chairman Glenn Cunningham for his use in drafting the final team report. 

Since the completion of that activity, I have pursued two lines of follow-on inquiry, 

primarily based on my own interests and expertise. This addendum to my original report 

describes my follow-on activities. 

The first line of inquiry is in the unexpected aerodynamic performance of the entry 

vehicle. The specific issue as express in Red Team final report1

 is the following, 

. 

• “Higher than expected attitude of lander (angle of attack) between 175 thru 251 

sec after entry (just prior to chute deploy) (ISA Z83007)” 

This higher than expected angle of attack might be explainable by a mischaracterization 

of the dynamic stability of the entry vehicle. Very roughly, prior to entry there was an 

expectation of a dynamic instability when the vehicle decelerates to around Mach 3. The 

entry data shows that potentially this instability occurred as high as Mach 6. An 

instability occurring higher in Mach number means that instabilities have longer time to 

grow and hence cause greater dispersions in attitude. 

At Ames Research Center, I consulted with Dr. Ethiraj Venkatapathy on potential causes 

for high Mach number dynamic instability. We both thought it important for future 

exploration missions to determine the cause of such an instability. Furthermore, we 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

34 of 47 

thought the NESC would be an appropriate organization to perform the analysis. Dr. 

Venkatapathy contacted Wayne Lee (JPL), MER EDL Chief Engineer, to discuss the 

issue. I was not present during their conversation, but was told by Dr. Venkatapathy that 

Wayne Lee and his team were still investigating this issue, and that Wayne felt JPL had 

sufficient and appropriate staff to complete the task. I concur that the EDL team is well 

equipped to address the issue. I do recommend that the results of their study be published 

for the broader community to review, such as an AIAA paper. 

The second follow-on inquiry was in regards to the Red Team recommendation, 

“Relative to atmospheric reconstruction, it is suggested that the Project was remiss in not 

flying pressure and temperature sensors for use during terminal descent and on the 

ground. Such sensors, with a likely mass of hundreds of grams, would have allowed 

separation of the density and drag coefficient errors sources, something for which the 

Reconstruction Team could only speculate. It is suggested that these sensors be added to 

the EDL reconstruction requirements of future landed systems.”1 

I think it beneficial to future missions to understand the relationship between engineering 

instrumentation and accuracy in EDL reconstruction. A study could be performed by the 

NESC that derives instrumentation requirements for particular levels of accuracy in EDL 

reconstruction. 

I discussed this idea with Dr. Venkatapathy, and he subsequently discussed it with 

Wayne Lee. I am told by Dr. Venkatapathy that Wayne Lee has been asked a similar 

question by Dave Lavery, Program Executive for Solar System Exploration, NASA HQ, 

but specific to MER. I recommend that the NESC review the response given by Wayne 

Lee, and then determine if a broader analysis is required. It may be that in answering the 

question specific to MER, the answer is broadly applicable and no further analysis is 

warranted. 

In summary, since completion of my participation as NESC representative to the MER 

EDL Red Team, I have further inquired about the unexpected excursion in angle of 

attack, and the Red Team recommendation for additional flight instrumentation. At this 

time, the MER project is responsibly pursuing both issues. I do not see need for NESC 

participation at this time. I do recommend that the results of the aerodynamic 

investigation be published in at least a conference paper, and the instrumentation analysis 

be review by the NESC to determine the range of applicability. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

35 of 47 

[1] Final Report of the Mars Exploration Rover (MER) Entry Descent and Landing 

(EDL) Red Team, Glenn Cunningham (Chairman), Jan. 17, 2004 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

36 of 47 

APPENDIX F 

Final Report of the 

Mars Exploration Rover (MER) 

Entry Descent and Landing (EDL) 

Red Team 

Glenn E. Cunningham 

Chairman 

January 17, 2004 

Jet Propulsion Laboratory 

California Institute of Technology 

Pasadena, California 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

37 of 47 

Final Report of the 

Mars Exploration Rover (MER) 

Entry Descent and Landing (EDL) 

Red Team 

3.1.1 Executive Summary 

The MER EDL Reconstruction Red Team assessed the performance of the MER 

Project’s MER-A EDL reconstruction activities. It observed an extremely well qualified 

reconstruction team that performed in an exceptional manner. The team had extensive 

performance data and utilized it well. The team rapidly identified the salient issues and 

properly prioritized their analysis of them. While their processes were not well 

documented in the normal flight operations manner, their previous experience with the 

design of the EDL and their significant expertise enabled them to perform in the 

exceptional manner observed. The Red Team finds that the MER-A reconstruction was 

well executed, that the proper issues were analyzed, and proper recommendations were 

made relative to modifications for the MER-B EDL. Some suggestions for future 

reconstruction activities are offered. The members of the Red Team felt extremely 

honored to have been participants in this activity. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

38 of 47 

INTRODUCTION 

The Mars Exploration Rover Entry, Descent and Landing (EDL) Red Team was 

chartered by the JPL Associate Director for Flight Projects and Mission Success to assess 

actual MER-A (Spirit) EDL reconstruction activities and results to identify any 

weaknesses/anomalies in the MER-A EDL for the benefit of MER-B (Opportunity). The 

Red Team’s membership is shown in attachment 1. 

The Red Team assessed the performance of the MER EDL Reconstruction Team during 

PORT 10 and provided a previous report on those findings. 

This report deals with the performance of the Project’s MER-A EDL reconstruction 

activities. 

RED TEAM OPERATIONS 

The Red Team convened to witness the actual MER A EDL events on January 4, 2004, 

and then again each day from January 5, 2004 (sol 2) through January 8, 2004 (sol 6) to 

assess the EDL reconstruction activities in the Reconstruction Team’s war room. The 

Red Team assigned a member or members to each of the Project’s reconstruction subteams. (For assignments, please see attachment 2.) The Red Team members assessed 

each sub-team’s approach to the apparent issues and, in some cases, participated with the 

sub-team’s analysis, as requested. On a daily basis, the full team sat-in on the full 

Reconstruction Team tag-up meetings. 

A daily assessment was prepared, and was sometimes presented to the Project 

management. 

After sol 6, it was determined that the Reconstruction Team had identified the significant 

performance issues of the MER-A EDL and had established a satisfactory plan to 

disposition each issue with respect to the MER-B EDL. Thus, the Red Team chose to 

stand-down, however the Chairman continued to track the continuing activities of the 

Reconstruction Team. 

On a daily basis, the Red Team asked itself the following questions as tools to assess the 

Reconstruction Team’s activities: 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

39 of 47 

• Did they have the correct data and use it properly?

• Did they identify the correct issues and work them in the correct priority? 

• Did they use the correct processes in doing their work?

The following section summaries the Red Team’s assessment of these questions. 

OVERALL PERFORMANCE OF THE RECONSTRUCTION ACTIVITY 

The EDL Reconstruction Team was well qualified, motivated, and had an appropriate set 

of tools to accomplish their objectives. The actual MER-A EDL activities were much 

better coordinated than the Red Team observed during PORT 10. We were impressed 

with the quality and quantity of work as well as the cooperation and exceptional strong 

team dynamics among the team members. There was an expectation of excellence while 

at the same time a willingness to support each other. The group was self-policing. 

Equally important was that members of the reconstruction team challenged each other. 

Members were sufficiently broad and had the technical depth to question the engineer in 

charge of another sub-team. The atmosphere was such that one's data and analysis was 

questioned, but not the individual's technical authority. Finally, there was an 

extraordinary amount of work performed during the week by associated JPL and LaRC 

personnel. Every day there were new analyses presented or tests results described from 

unheralded engineering work performed throughout the night. 

Relying on their extensive development experience and a tremendous amount of critical 

event reconstruction data (MGS relay, ODY relay and DTE playbacks), the MER EDL

team did an outstanding job analyzing the MER-A entry, descent and landing system 

performance. Their process employed an appropriate balance of data discovery, 

interpretation and debate. This process was completed quicker than planned due to the 

exemplary performance of the MGS and Odyssey spacecraft in returning this critical data 

and a well-organized process of data distribution, led by Erik Bailey. 

The team was careful to use the data properly, defining which insights were gleaned 

directly from the data products and which were inferred. When questions arose outside 

the expertise of sub-team members, they immediately brought others into the group 

discussion. After a day of data discovery, they identified atmosphere reconstruction and 

chute-deploy timing as priority issues and began to work them with the proper priority. 

In the following days, as additional data became available, DRL performance and chute 

deploy attitude were added to this high priority list. The proper priorities were 

established. The team jumped on any parameter that was observed to violate its expected 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

40 of 47 

value, even if this expected value was not near a predicted failure condition. The 

incredible amount of additional analysis and testing performed by the DRL team (led by 

Adam Steltzner) was the most remarkable example of this. In many cases, data was 

validated by an independent means (e.g., chute deploy attitude was computed 

independently from quaternion and accelerometer data). The tendency to blame 

anomalies on the atmosphere (since there was no direct atmospheric measurement) was 

fought until all other system performance possibilities were examined. Each day’s results 

were well calibrated and re-planned through two complete team meetings run by Wayne 

Lee and Rob Manning. The focus of these meetings and prioritization of key findings 

improved each day. The red/yellow/green parameter performance table compiled and 

discussed at these meetings was a very useful way to summarize present status and 

identify remaining priorities. 

RED TEAM’S LIST OF MAJOR EDL ISSUES 

The Red Team identified the following major issues as it assessed the Project’s EDL 

reconstruction process. These issues correlate well with the Reconstruction Team’s 

“yellow” EDL performance items. We, as well as the Reconstruction Team, found no 

showstoppers, or “red” performance issues. (ISA numbers are shown if known.)

• Reconstructed atmosphere density was lower prior to parachute deploy and higher 

after parachute deploy than predicted by the model used 

Parachute deployment time 2 sigma late (ISA Z83004)

• DRL over performed (ISA Z83006) 

• Fair amount of vertical velocity at bridle cut – (wind gust near RAD fire?) (ISA 

Z83010) 

• Unexplained results of the parachute algorithm in last 2 sec 

• Higher than expected attitude of lander (angle of attack) between 175 thru 251 sec 

after entry (just prior to chute deploy) (ISA Z83007)

• Undesirable performance of peak width check in DIMES algorithm 

• LCP - RF signal observed during bouncing (ISA Z83009)

• Various pyro current spikes 

• Various chassis voltage spikes 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

41 of 47 

SUB-TEAM PERFORMANCE ASSESSMENTS 

The Atmosphere and Entry Dynamics sub-teams functioned well together over the week. 

In particular, a significant amount of discussion was required to bring the atmospheric 

prediction scientists and atmospheric density engineering reconstruction into agreement. 

The ability to complete this task under stringent time constraints is commendable. 

The Flight Mechanics sub-team was well qualified, motivated, and had an appropriate set 

of tools. The data was used properly with cross checks on the validity of the data where 

this was possible. The key issues were identified and the work was properly prioritized. 

Key resources at LaRC were effectively used to address identified issues. Although a 

process for this work was not documented (in the normal mission operations manner) the 

process worked smoothly with the correct interfaces and teaming arrangements 

developed to effectively complete the reconstruction and development activities. The 

team members were very cooperative and respectful within the team and outside the team 

and appropriately incorporated the EDL Red Team in their activities. 

The members of the Parachute sub-team learned a lot about parachutes and, in one Red 

Team member’s opinion, became legitimate peers of the "parachute experts" that dogged 

their footsteps for 2+ years and the parachute designers from industry that built the 

parachutes. Therefore, they had no problem identifying what the primary parachute 

issues were and how to work them. The Red Team member assigned to them suggests 

that he was more of a nuisance than an asset to them; they did an excellent job on their 

own. This team's work with the Atmospheric Scientists and the trajectory people was a 

notable highlight because all three groups gained a better systems perspective of MER-A 

EDL as a result. 

The Navigation Team and Navigation Advisory Group (NAG) have done an excellent job 

of conducting the approach navigation effort on the MER mission and the EDL effort. 

The team has recognized, utilized, and made significant advances on the processes, 

procedures and tools established by earlier missions. The Navigation team looks to be 

fully engaged with the Project and the relevant spacecraft subsystems, as well as the EDL 

team, ensuring a confident level of communications and interface between the Navigation 

team and the Flight team. 

The telecom support to the EDL Reconstruction Team was viewed as an adjunct activity 

and not as part of the main line EDL reconstruction process. The Reconstruction Team 

got away with this because the MER-A EDL was successful and the semaphore analyses 

were not particularly valuable in the overall context of having a large amount of relay 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

42 of 47 

data. But keeping telecom on the perimeter of the EDL team would have been a severe 

encumbrance had there been a mishap during EDL. 

CONCURRENCE WITH IMPACTS TO MER-B EDL 

The Red Team concurs with the two major recommendations made by the Reconstruction 

Team. First, that no “shallowing” maneuver is necessary for MER-B, and, second, that 

timeline margin, if needed, can be safety obtained by increasing the dynamic pressure at 

which the parachute is deployed from 725 Pa (used on MER-A) to 750 Pa. 

SUGGESTIONS FOR FUTURE RECONSTRUCTION ACTIVITIES 

While we found the MER reconstruction activities to have been very well executed, we 

could not help but offer several suggestions for process improvement the next time this 

activity is executed. 

Relative to atmospheric reconstruction, it is suggested that the Project was remiss in not 

flying pressure and temperature sensors for use during terminal descent and on the 

ground. Such sensors, with a likely mass of hundreds of grams, would have allowed 

separation of the density and drag coefficient errors sources, something for which the 

Reconstruction Team could only speculate. It is suggested that these sensors be added to 

the EDL reconstruction requirements of future landed systems. 

A suggested process improvement is the development of a software tool to visually 

display the EDL timeline. Multiple variables could be plotted and displayed 

simultaneously as a function of trajectory variables. For example, it would have been 

useful to see the accelerometer data plotted as a function of time along with entry speed, 

Mach number and altitude. EDL events could also be noted on the timeline. A simple 

switch would then permit plotting of the variables as a function of altitude, for example. 

In this way, a more comprehensive and integrated view of the EDL sequence could be 

communicated. Another process improvement would be an automated frequency 

decomposition of the data. Several times we witnessed a frequency analysis by "eyeballing" the data. Although eyeballing is sufficient for the dominant modes, it does not 

reveal power in other parts of the spectrum. Stacking up multiple data traces, denoting 

EDL events, and showing frequency content would be a powerful analysis approach. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

43 of 47 

We all felt the reconstruction process was hindered by the lack of a reference timeline 

(table or schematic) that could be referenced when needed. It was asserted that everyone 

had these numbers in their heads, but in the decision meetings it was clear that they did 

not. 

One of our earlier PORT 10 concerns was the lack of clear decision criteria for change 

that was still evident in the MER-A reconstruction process. 

Because the analysis of the semaphore data may become a significant tool given an EDL 

anomaly in the future, every effort should be made to integrate telecom fully within the 

Reconstruction Team. 

CONCLUSIONS 

The Red Team finds that the MER-A reconstruction was well executed, that the proper 

issues were analyzed, and proper recommendations were made relative to modifications 

for the MER-B EDL. 

The Red Team found its assessment of MER- A EDL reconstruction process to be a 

stimulating assignment and feels quite honored to have associated with such a fine 

engineering group as the MER EDL Reconstruction Team. 

ACKNOWLEDGEMENTS 

Red Team members Bobby Braun, Claude Graves, Carl Peterson, Dean Kontinos, Bob 

Mase, Dave Spencer, and Gordon Wood contributed to this report. 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

44 of 47 

Attachment 1 

MER EDL Red Team Members 

Bobby Braun – Georgia Tech 

Glenn E. Cunningham – Chairman – Consultant 

Claude Graves – NESC rep – JSC 

Dean Kontinos – NESC rep – ARC 

Gentry Lee – JPL 

Dankai Liu – JPL 

Bob Mase – JPL 

Carl Peterson – Sandia 

Dave Spencer – JPL 

Sam Thurman – JPL 

Jeff Umland – JPL 

Gordon Wood – Consultant 

Attachment 2 

Red Team Member Assignments 

(Shown in italics) 

Task Lead (Reconstruction Task Leader: Wayne Lee) 

Glenn Cunningham 

Flight System (Reconstruction Sub-team leader: Willis) 

Dankai Liu 

 Gordon Wood 

 Gentry Lee

Approach Navigation and Entry Doppler (Reconstruction Sub-team leader: Knocke) 

Bob Mase 

Entry Dynamics (Desai) 

Claude Graves (NESC, JSC)

 Bobby Braun 

Parachute Deployment Algorithm (Knocke) 

Carl Peterson 

 Dave Spencer 

Parachute Inflation and Performance (Bruno) 

Carl Peterson 

Descent Dynamics, Deployments and Separations (Steltzner) 

Jeff Umland 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

45 of 47 

 Dean Kontinos 

Descent Algorithms and Bridle Cut Performance (San Martin) 

Dave Spencer 

 Sam Thurman

Bounce Trajectory and Dynamics (Grover) 

 Gentry Lee 

Critical Deployments (Grecko) 

Jeff Umland 

Atmosphere and Wind Assessment (Kass) 

Bobby Braun 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

46 of 47 

Plan Approval and Document Revision History 

Approved: Original signature on file 8/20/04 

NESC Director Date 

Version Description of Revision Author Effective 

Date 
NASA Engineering and Safety Center

Consultation Position Paper

Document #: 

RP-04-10 

Version #: 

1.0

Title:

Mars Exploration Rover Flight Operations 

Technical Consultation 

Page #: 

47 of 47 

Signature Page 

NESC Technical Consultation Team
REPORT DOCUMENTATION PAGE Form Approved

OMB No. 0704-0188

2. REPORT TYPE 

Technical Memorandum

 4. TITLE AND SUBTITLE

Mars Exploration Rover Flight Operations Technical Consultation 

5a. CONTRACT NUMBER

 6. AUTHOR(S)

Leckrone, Dave S.; Null, Cynthia H.; Caldwell, John; Graves, Claude; 

Kontinos, Dean A.

 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

NASA Langley Research Center

Hampton, VA 23681-2199

 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

National Aeronautics and Space Administration

Washington, DC 20546-0001

 8. PERFORMING ORGANIZATION

 REPORT NUMBER

L-19652 NESC-RP-04-10/03-004-E

10. SPONSOR/MONITOR'S ACRONYM(S)

NASA

13. SUPPLEMENTARY NOTES

12. DISTRIBUTION/AVAILABILITY STATEMENT

Unclassified - Unlimited

Subject Category: 18-Spacecraft Design, Testing and Performance

Availability: NASA CASI (443) 757-5802

19a. NAME OF RESPONSIBLE PERSON

STI Help Desk (email: help@sti.nasa.gov)

14. ABSTRACT

The Mars Exploration Rover (MER) Project at the Jet Propulsion Laboratory developed two golf-cart size robotic vehicles, 

Spirit and Opportunity, for geological exploration of designated target areas on the surface of Mars. The primary scientific 

objective of these missions was the search for evidence of the presence of water on or near the surface of the planet during its 

history. Spirit and Opportunity were launched on June 10 and July 7, 2003, with their respective landings scheduled for 

January 4 and January 25, 2004 (UTC). NASA views the MER missions as particularly critical because of their scientific 

importance in the ongoing search for conditions under which life might have existed elsewhere in the solar system, because of 

their high level of public interest and because more than half of all prior missions launched to Mars internationally have failed. 

15. SUBJECT TERMS

EDL; MER; NDE; UTC

18. NUMBER

 OF 

 PAGES

52

19b. TELEPHONE NUMBER (Include area code)

(443) 757-5802

a. REPORT

U

c. THIS PAGE

U

b. ABSTRACT

U

17. LIMITATION OF 

 ABSTRACT

UU

Prescribed by ANSI Std. Z39.18

Standard Form 298 (Rev. 8-98)

3. DATES COVERED (From - To)

Sept. 2003-Mar. 2004

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

5d. PROJECT NUMBER

5e. TASK NUMBER

5f. WORK UNIT NUMBER

869021.06.07.05.99

11. SPONSOR/MONITOR'S REPORT

 NUMBER(S)

NASA/TM-2009-215713

16. SECURITY CLASSIFICATION OF:

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, 

gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this 

collection of information, including suggestions for reducing this burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and 

Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person 

shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.

PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS.

1. REPORT DATE (DD-MM-YYYY)

01- 04 - 2009