Office Of cOmmercial Space TranSpOrTaTiOn 

Commercial Space 

Transportation 

Commercial Space Transportation 

FY-2005

ReseaRch and development 

accomplishments 

Destination FAA OctOber 2005 HQ-026505 

AST FY 2005 R&D Accomplishments 
NOTICE

Use of trade names, services, or images associated with corporate 

entities in this document does not constitute official endorsement 

of such products, services, or corporate entities, either expressed or 

implied, by the Federal Aviation Administration. 

Available from 

Federal Aviation Administration

Associate Administrator for Commercial Space Transportation

800 Independence Avenue, S.W., Rm. 331

Washington, D.C. 20591

Photo credits for front cover: 

Upper right corner image, courtesy of FAA/AST.

Center right image, courtesy of Scaled Composites, LLC. (Mojave, California)

Lower right image, courtesy of NASA.

Center image, courtesy of NASA.

Lower left image: Sea Launch Company, LLC. (Long Beach, California)

All other images created or purchased by Futron Corporation (Bethesda, MD)
Office Of cOmmercial Space TranSpOrTaTiOn 

Mission 

AST’s mission is to ensure 

protection of the public, property, 

and the national security and 

foreign policy interests of the 

United States during a commercial 

launch or reentry activity and 

to encourage, facilitate, and 

promote U.S. commercial space 

transportation.

AST FY 2005 R&D Accomplishments 
Office Of cOmmercial Space TranSpOrTaTiOn 

Introduction 

This document describes five Research and Development

(R&D) projects undertaken by the Office of Commercial Space

Transportation (AST) in the Federal Aviation Administration

(FAA) during fiscal year 2005. Three new research projects were

selected and assigned to an AST division. Work also continued

on two projects, one initiated in FY 2003 and the other in FY

2004. In addition to a description of each project, a summary of

accomplishments to date is provided.

The AST safety research supports the development of the

policy, standards, and guidance material needed to meet FAA

goals and objectives. Such research is also essential in developing

the knowledge necessary to maintain and improve FAA/AST

materials used to verify that the products and procedures

of launch vehicle and site operator licensees and applicants

adequately comply with applicable safety standards.

To that end,AST formulated and instituted an R&D activity to

support its mission and the FAA’s strategic goal of safety. TheAST

Research and Development Plan provides a process for effectively

applying resources forresearch based on clearly identified safety

priorities each fiscal year. This Plan was used to solicit candidate

research projects from internal sources, such as AST aerospace

engineers and projects. External sources, such as the Commercial

Space TransportationAdvisory Committee (COMSTAC) Reusable

Launch VehicleWorking Group (RLVWG) and Launch Operations

Support Working Group (LOSWG), were also solicited.

First, the AST R&D Advisory Board evaluated candidate

research projects for relevance to AST’s mission, relative

importance, and cost. Second, the AST R&D Advisory Board

ranked the candidate research projects to arrive at a prioritized list

to present to theAST R&D Senior Steering Committee forreview.

Third, theAST R&D Senior Steering Committee selected the R&D

projects to undertake in FY 2005 that had the greatest potential

to fulfill AST’s mission and to meet its budgeted requirements.

Lastly, the R&D Advisory Board and Senior Steering Committee

held periodic R&D project status reviews throughout the year.

AST FY 2005 R&D Accomplishments 1
Office Of cOmmercial Space TranSpOrTaTiOn 

Debris Risk Analysis 

As part of the commercial launch licensing process, AST

uses computer-based models to develop casualty expectations

associated with launch accidents affecting the uninvolved

public. This research project evaluates the fidelity ofthe current

computer models of buildings and how people within them

would be affected by debris resulting from such accidents.

Validity ofAST’s models is important because these calculated

results are used to establish limits on launch parameters and

insurance requirements, both of which may cause considerable

burden to launch operators.

This project compares data from actual explosive-created

damage to inhabited buildings, and the resulting debris-caused

casualties, with the computed results from AST models. Data

collected from the bombings at the Khobar Towers, London

during WWII, Oklahoma City, and SCUD missile attacks on

Israel provide the basis for this comparison.		

Before this evaluation, the AST models had been judged

too conservative, but this anecdotal view does not appear to

be the case so far. To date, only the Khobar Towers data have

been evaluated, and the analysis revealed a good correlation

between the AST models and real-world data. This initial

finding remains to be supported by the research on the other

three locations.

This project is slated for completion in 2006. 

Supports FAA Strategic Goal: SAFETY 

AST FY 2005 R&D Accomplishments 3
Office Of cOmmercial Space TranSpOrTaTiOn 

Reconfigurable Control Allocations 

for Reusable Launch Vehicles 

AST initiated a study on reconfigurable control allocations

for next generation reusable launch vehicles (RLVs) in FY2005.

This study evaluated advanced guidance and control methods

that may have significant potential to increase the safety and

reliability of future RLVs and to reduce the cost of performing

trajectory guidance as well as navigation and control analysis.

Management of emergency situations arising from control

surface degradation or actuator failure, using other available

operating mechanisms and a reconfigured adaptive control

strategy, may improve safe mission return or abort scenarios.

This generic problem widely affects the general class of RLVs

and is of great importance from a safety perspective.

Having RLV control algorithms adapt to changing flight

conditions, using available control surfaces and effectors, would

be desirable. A key aspect is the ability of the guidance laws

to distribute control responsibility among available actuators

in a reconfigured mode with a new management strategy that

adjusts the flight profile to reflect the modified goal, such as

safe mission return.

To this end,AST built upon the NASA-derived concept of an

executive reconfiguration control scheme that is independent

of the physical hardware layer if a major component failure

occurs. Such a hierarchical scheme means the overall

reconfiguration control allocation arrangement is design and

device independent. Therefore, the approach applies to all

generic RLV physical equipment incorporating an autopilot.

4 AST FY 2005 R&D Accomplishments 
Office Of cOmmercial Space TranSpOrTaTiOn 

Without NN Compensation 

Augmented by NN 

1.5 

1 

0.5 

0 

-0.5 

-1 

1 

0.5 

0 

-0.5 

-1 

0 1 2 3 4 5 6 7 8 9 10 

Commanded Position 

Reference Model Response 

Actual Response 

An adaptive controller example, designed around a linearly	

approximated model of the actual system, was studied. Any	

nonlinearities or model errors, such as actuator failures,	

affect the performance of the control system and potentially	

lead to instability. To compensate for these modeling	

deficiencies, a neural network (NN) was used to augment	

linear controllers.	 Figure 1	 shows the	 comparison	between	

the system response, with and without NN compensation, in	

response to commanded plant (RLV) dynamics in the presence	

of unmodeled uncertainties and the resulting improvement in	

system response.

Supports FAA Strategic Goal: SAFETY 

AST FY 2005 R&D Accomplishments 5
Office Of cOmmercial Space TranSpOrTaTiOn 

Radio Frequency Blackout During Reusable 

Launch Vehicle Reentry

A study was completed to assess the radio frequency	

blackout phenomenon caused by plasma generation around	

reusable launch vehicles (RLVs) during reentry. Methods	

for mitigating this condition that might apply to prospective	

commercial space vehicles for operation within the National	

Airspace System and Space andAir TrafficManagement System	

were	evaluated.

Toward this end, the ability to predict the ionized flow	

field and, thereby, identify the altitude of blackout onset has	

been demonstrated. This phenomenon is most likely	to be	

encountered in the high-altitude regime. Four mitigation	

methods, under active and passive classes, were studied:	

aerodynamic shaping, injection of liquids, application of	

magnetic fields, and use of high frequencies.		

Passive methods, such as aerodynamic shaping and use	

of high frequencies, appear the most promising. Results	

were derived for a body with sharp-tipped antenna, and the	

effectiveness compared to Shuttle and Kistler orbital vehicles.	

Findings indicate that through such methods it may be possible	

to significantly reduce the signal blackout and attenuation	

periods to maintain continuity of communications.		

Such passive approaches, which alleviate the signal	

attenuation condition, might be more amenable for commercial	

segment reentry RLV bodies for cost effectiveness reasons.

Secondly, initial efforts to identify frequency bands suitable	

for communications in the presence of plasma shielding has	

been	made.

Supports FAA Strategic Goal: SAFETY 

6 AST FY 2005 R&D Accomplishments 
Office Of cOmmercial Space TranSpOrTaTiOn 

Non-Traditional Flight Safety Systems and 

Integrated Vehicle Health Monitoring

TAST completed a follow-on study to the report on nontraditional flight safety systems performed in fiscal year 2003.

Flight safety systems minimize the threat to public safety and	

property posed by a malfunctioning launch vehicle. Nontraditional versions of these systems include fully autonomous	

systems and semi-autonomous systems that interface with	

pilots, ground controllers, or both. AST anticipates the	

application of autonomous and semi-autonomous methods	

to spacecraft safety and health-monitoring systems in the	

near future. Proper regulation of these systems is essential to	

maintaining a consistent level of safety at a variety of ranges	

and	spaceports.

In the 2003 study,AST developed a verification framework	

for the regulatory approval of non-traditional systems. In	

an effort to gauge the effectiveness of this methodology, this	

framework was applied to an autonomous flight safety system	

being developed and tested by NASA at its Wallops Flight	

Facility. Because this program is still evolving, portions of the	

test evaluation relied on current plans as well as the results	

of completed tests. Results and lessons learned during this	

trial application provided AST with additional insight into	

the various approaches for granting regulatory approval for	

commercial applications of these types of	systems.

1Fudge, Michael, Thomas Stagliano, and Sunny Tsiao. Non-Traditional	

Flight Safety Systems & Integrated Vehicle Health Management Systems	

Descriptions of Proposed & Existing Systems and Enabling Technologies &	

Verification Methods: Final Report. Contract DTFA01-01-D03013, Delivery	

Order 3. Prepared by ITT Industries, Advance Engineering & Sciences	

Division, forthe FAAOffice of theAssociateAdministratorfor Commercial	

Space Transportation. August 26, 2003. (See http://ast.faa.gov/files/pdf/

DO3_Report_final.pdf, accessed September 23,	2005.)

AST FY 2005 R&D Accomplishments 7
Office Of cOmmercial Space TranSpOrTaTiOn 

Evaluating Expendable Launch Vehicle 

Weather Delays

A study	 aimed	 at	 identifying	 the	 top	 weather-related	

reasons	 for	 delays	 and	 scrubs	 experienced	 by	 expendable	

launch	 vehicles	 (ELVs)	 was	 completed.	 Weather	 plays	 a	

direct role on all aspects of launch operations, starting with	

prelaunch operations, continuing through vehicle processing,	

and ending with mission success. Any delay or scrub directly	

influences launch costs, which can easily exceed hundreds of	

thousands of	dollars.

This study provides useful information regarding typical	

launch	 delays	 and	 scrubs	 and	 expected	 environmental	

conditions on a given range throughout the year.

Such information will help commercial ELV launch operators	

make	 sound	 decisions	 regarding	 launch	 operations	 and	

planning.	 These	 results	 highlight	 new	 methodologies	 and	

help identify areas for future studies to aide commercial ELV	

operations.

Over	 300	 launches	 from	 the	 Eastern	 Range	 at	 Cape	

Canaveral,	 Florida,	 and	 the	 Western	 Range	 at	 Vandenberg	

Air Force Base, California, were examined to determine the	

most	 frequent	 types	 of	 weather-related	 delays	 and	 scrubs	

that	 occurred	 from	 1988	 through	 2005.	 In	 addition,	 data	

from several recent launches at Kodiak Launch Complex in	

Kodiak, Alaska,	were	reviewed.	Weather	delays	 and	 scrubs	

were divided into the following categories:	

8 AST FY 2005 R&D Accomplishments 
Office Of cOmmercial Space TranSpOrTaTiOn 

Lightning Launch	

Commit	Criteria

Range	

Safety

User Weather	

Constraints

Other

Natural	Lightning Blast Lightning Down range	weather

Clouds Ceiling Precipitation

Smoke	plumes Debris Solar

Electric	fields Toxics Temperature

Triboelectrification Visibility Winds

At	 both	 the	 Eastern	 Range	 and	 the	 Western	 Range,	 21	

percent	 of	 the	 scrubs	 and	 8	 percent	 of	 the	 delays	 were	

weather-related.	 However,	 these	 events	 were	 caused	 by	

differing constraints during differing times of the year. For	

example,	 Eastern	 Range	 scrubs	 frequently	 occurred	 during	

the	 summer	 and	 were	 typically	 influenced	 by	 lightning	

launch	 commit	 criteria.	 Western	 Range	 delays	 and	 scrubs	

occurred primarily from December to May and were usually	

associated with user constraints, such as upper level winds.

Note, however, down range weather was responsible for 13	

percent of these occurrences. While insufficient data exists to	

develop statistically valid trends for Kodiak, its top weatherrelated delays and scrubs occurred during the summer and	

showed a linkage to such range safety constraints as visibility	

and to lightning launch commit criteria, such as	clouds.

Supports FAA Strategic Goal: SAFETY 

AST FY 2005 R&D Accomplishments 9