MCR8&1329 

NAS8-36609 

' - OPO-854 

OR47 * Volume II 

Final 

Technical 

Report June 1986 

Supporting Research and 

Technology Report 

6 

c 

Concept Definition 

Study for Recovery 

of Tumbling 

Satellites 

__ 

(BASA-C3-)19229) COUCEPT DEFIUITfObl STPOP N88-14117 

2: SUPPORTING BESEARCH MD TECHNOLOGY PBPORT Final Technical Report {Hartin Harietta Unclas 

Aerospace) 13 p CSCL 228 G3/18 0114848 

FOR RECOVERY OF TWHBLIYG SATELLITES. , VOLBBE 
MCR-86-1329 

Contract NAS8-36609 

DPD-654 

DR-6,7 

Volume II 

Final 

Technical 

Report June 1986 

Supporting Research and 

Technology Report 

CONCEPT DEFINITION STUDY 

FOR RECOVERY OF 

TUMBLING SATELLITES 

Prepared for: 

National Aeronautics and Space Administration 

Marshail Space Flight Center 

Alabama 35812 

Prepared by: 

0. A. Cable 

W. L. Deftocher, Jr. 

J. A. Cathcart 

M. G. Keeley 

L. Madayev 

T. K. Nguyen 

J. R. Preese 

Program Manager 

- MARTIN MARIETTA 

DENVER AEROSPACE 

P. 0. Box 179 

Denver, Colorado 80201 
FOREWORD 

; 

This document was prepared by Marti n Marietta Corporation under contract 

NAS8-36609, Concept Definition Study for Recovery of Tumbling Satellites, Data 

Procurement Document 654 to fulfill the requirements of Data Requirement 6, 

Volune 1, Final Study Report, and Data Requi rement 7, Volume 11, Supporting 

Research and Technology Report. 

C. Marshall Space Flight Center of the National Aeronautics and Space 

Administration under the technical direction of Mr. Herbert Lenox and Mr. 

Stephen B. Hall, as Contract Technical Managers. 

This effort was accomplished for the George 

ii 
CONTENTS 

3 

Page 

i 

ii 

iii 

Title Page . . . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . . . . . . . Foreword ...... .... .... ..... ..... ............ ........ ... Table of Contents . .. . . . . . . . . . . . . . . . . ... .. . . . .. . . . . .. . 

1.0 SUPPORTING RESEARCH AND TECHNOLOGY REPORT . ............. 1-1 

1.1 1-1 

1.2 1-1 

1.3 1-3 

1.4 Contact Dynamics between Recovery System and Target .... 1-4 

1.5 1-6 

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Deployment Dynamics of Capture Device . . . . . . . . . . . . . . . . . . 

Operator Control Capabi 1 i ty Assessments . . . . . . . . . . . . . . . . 

P1 anni ng Estimates of Di sabled Sate1 li te Moti on . . . . . . . . 

iii 
1.0 SUPPORTING RESEARCH AND TECHNOLOGY REPORT 1 

1 .l Introduction e 

The Supporting Research and Technology (SR&T) Report for the Tumbli ng 

Satellite Recovery (TSR) conceptual definition stuQ is presented in the Data 

Requirements Description format provided in Data Procurement Document 

(DPD)-654. 

Definition, to take advantage of the close association between the conceptual 

design effort in this task and the constant need to assess the technology 

status of any new systems or components under consideration during conceptual 

design. 

The SR&T report was prepared as a subtask of Task 2, Concept 

The MMDA study team did not identify any problem amas requi ring new 

state-of-the-art technology development initiatives. 

number of areas where research and laboratory experiments could support 

resolution of technology issues that could lead to development of a cost 

efficient remote, disabled satellite recovery system. 

They did identify a 

. The SR&T report includes title, status information, justification, technical 

plan, resource requi rements data and target schedule, wherein it was feasible 

in regard to the low level of effort directed for this task by the Contract 

Technical Monitor. 

1 .2 P1 anni na Estimates of Di sabl ed Sate1 1 i te Motion 

A) Title - Planning Estimates of Disabled Satellite Motion. 

8) Status - Przsent capabi li ty unknown. 

are available to generate estimate of capability. 

Equipment and trai ned personnel 

1-1 
C.) Justification - The MMC conceptual definition of a TSR kit includes a 

modular system, composed of a number of subsystem mechanisms that can 

be readily integrated into varying combinations. 

the user to quickly configure a tailored remote, disabled satellite 

recovery kit to meet a broad spectrum of potential scenarios. 

Mission planners will require satellite orientation and motion data 

on each Emote, disabled satellite to determine what mix of equipment 

is required for each specific mission. 

This will enable 

D) Technical Plan 

1 Objectives - Determine the capability of U.S. earth-based 

satellite tracking facilities to adequately det2rmine the 

ori entati on and moti on rates of di sabled sate1 1 i tes. 

2) Technical Approach - Request that a supporting study be 

conducted for NASA by the U.S. Space Comnand to meet the stated 

object1 ve. 

E) Resource Requi rements 

3) 

Manpower - Manpower estimate is one man year for FY 87, one man 

year for FY 88. 

Specialized Facilities - Facilities exist. 

data can be obtained by Haystack Radar at Westford, MA; 

laboratory and computer facilities are available at Lincoln 

Laboratory in Lexi ngton, MA. 

Satellite tracking 

Funding - Funding requi rements equate to two manyears of ci vi 1 

service engineering level direct labor, estimated at $200,000. 

F) Target Schedule - The requi red analysis is schedule constrained, 

based on personnel availability. 

effort is two years. 

The estimated duration of the study 

e 

1-2 
1.3 Deployment Dynamics of Capture Device 

Title - Deployment Dynamics of Capture Device 

Status - These analyses have not been conducted previously. The 

technical understanding of the analytical processes requi red to 

conduct the study and develop the softwam is high. 

Justification - The deployment of a lengthy, cantilevered extend1 ble 

boom and envelopment grapple mechanism that changes its shape, and 

the spin-up of this system will produce momentum effects and 

structural modes that must be determi ned to evaluate the potential 

impact on OMV attitude control capacity. 

Technical Plan 

1) objectives - The objective of this study effort is to model the 

momentum effects and structural modes of a TSR kit mated to an 

OMV transfer whicle and to evaluate the capacity of OMV to 

control this recovery system during deployment, configuration 

changes, and spi n-up. 

2) Technical Approach - Develop a set of offline (non-real-time) 

softwam simulation programs to model. (1 ) the momentum effects 

of boom deployment, grapple mecnanisnr deployment and spin-up of 

systems to 5-50 rpm, (2) the structural modes of this inherently 

flexible recovery system, and (3) the resultant impact of Wth 

on OMV control capabi 1 ity. 

Resource Requi rements 

1) Manpower - Manpower estimate is twelve man months. 

2) Specialized Facilities - Computer facilities exist at MSFC and 

MMC, programs can be written in transportable manner. 

1-3 
3- 

3) Funding - Funding requi rements a= twelve man months of di rect 

engineering labor estimated at $100,000 and $10,000 in computer 

costs. 

. 

F) Target Schedule - The 

based on avai labi 1 i ty 

duration of the study 

requi red analysi s is schedule constrained, 

of personnel and funding. 

effort is six months. 

The estimated 

1.4 Contact Dynamics Between Recovery System and Target 

Title - Contact Dynamics Between Recovery System and Target 

Status - Tests are required to deterinire forces, torques and 

resultant position changes of target and recovery devices caused by 

contact between target and recovery systems during recovery 

operations. These tests have not been conducted previously. The 

general understanding of the analytical processes reaui red to conduct 

this activity is fair. 

Justification - The complex interactions between a spinning object 

and a device attempting to match spin rate and phase angle with the 

spinning object after the initial contact has been made have not been 

examined. The resultant forces and motions may be significant enough 

to impact the conceptual design'of the eventual recovery system. 

Technical Plan 

1 ) Objective - The overall objective is to model the forces and 

torques and resultant positional cnanges induced by contact 

dynamics created by requi red contact with a target prior to 

rigidi tation of target/recovery system. 

support: determination of potenti a1 target damage assessment; 

forces imposed/structural requi rements on recovery system; 

determination of type of recovery grapple inechanism (gripper vs 

enveloper); and assessment of OMV attitude control system 

adequacy for this phase of the recovery mission. 

These models wi 11 

1-4 
Technical Approach - The initial modeling phase rjbuld include 

development of software simulation packages to model all contact 

dynamics forces and torques between a spinning target and a spin 

rate matching recovery system. 

valuable approximations of the scale of foxes and torques 

created by contact during recovery operations and of resultant 

relative moti on. 

This effort will provide 

A follow-on activity would include deuelopment of hardware 

equipment capable of physically performing a recovery acti vity 

with spinning target and recovery device. This task would 

require building a scaled, composite of the future recovery 

target mission model. A mockup of a representative recovery 

system would also be built with load sensors on the grapple 

mechanism. The hardware load cell array would be integrated 

into the realtime software simulation to enable measurement of 

contact torques and forces. OMV/TSR and target states would 

then be generatsd in real time and with this data, estimates of 

new relative positions could be generated. 

The hardware demonstration unit will refine the estimates of 

potential target damage, structural requirements of the recovery 

system and potential impacts on OMV attitude control 

raqui rements for thi s mi ssi on. 

The results produced from these tests will provide clarity to 

questions related to the potential need for zero-gravity tests 

related to recovery system contact dynamics. 

Phase 1 - Software Simulations 

E) Resource Requi rements 

1) Manpower - Manpower estimate is 18 man months. 

2) Specialized Facilities - Computer facilities exist at MSFC and 

at MdC, programs can be written in transportable manner. 

1-5 
3) Funding - Funding estimate is for 18 man knths of direct 

engineering labor at $150,000 and $20,000 in computer costs. 

F) Target Schedule - The required analysis is schedule constrained, 

based on availability of personnel and funding. 

of the study effort is 12 months. 

Estimated duration 

Phase 2 - Hardware Simulations 

I E) Resource Requi rements 

1 ) Manpower - Manpower estimate is 3.5 man years to design and 

build hardware and software, and integrate and test the 

si mu1 ati on system. 

2) Specialized Facilities - Facilities exist both at MSFC and at 

MMC. 

3) Funding - Funding estimate is 3.5 man years of direct 

materi a1 , and computer costs. 

I engineering labor at $350,000 and $150,000 in equipment, 

F) Target Schedule - This hardware and software development is scnedule 

constrained, and should be accomplished after Phase 1 nas been 

completed. The activity would be accomplished during a 15-month 

I pe ri od. 

1 .5 Ope rator Control Capabi 1 i ty Assessments 

A) - Title - Operator Control Capability Assessments 

B) Status - These types of tests nave been conducted on a very limited 

scale. Tests are required to determine the satellite recovery 

operator control capability requi red to conduct disabled satellite 

operations and to identify needed supporting hardware. Simulation 

facilities exist and have been operational for over one year. 

f 

1-6 
C) Justification -' Previously conducted tests on related bMV and Manned 

Maneuvering Unit (MMU) tests have indicated that operator workload on 

much simpler tasks is very high, due to cmunications delay in 

on-orbit teleoperations and difficulty in performing operations 

requi ri ng preci si on a1 i gnnent of mec hani SIRS when trans1 ati on and 

rotati on actions are goi ng on simultaneously. Sate1 1 ite recovery 

operations include translation to the target, spin axis alignment, 

spin rate matching and grapple closure, performed in the environment 

of contact dynamics inhemnt in conducting a rigid grapple of a 

spi nni ng sate1 1 i te . 

< 

a 

D) Technical Plan 

1) Objective - The objective of this task is to assess the 

capabilities/ limitations of operators conducting teleoperated 

satellite recovery operations. The tests will include 

evaluation of the operations capability to identify the 

position of the target spacecraft's spin axis, the aPility to 

align the TSR kit axis with the target spin axis, the ability to 

match spin rate and to synchronize or phase the position of the 

recovery system grapple mechanism with the spinning target. 

related objective is to evaluate mission complexity to determine 

whether the OMV and TSR kit operation will require one or more 

operators. In addition, this analysis effort will provide 

insight on the type of sensors needed, the types of displays 

requi red, coordinate transformati ons needed to provi de optimum 

target views, methods of compensating for time delays, and will 

support development of an overall operations philosophy. 

A 

2) Technical Approach - The initial phases of this test will be 

conducted with computer graphic simulations. The computer 

operator controls and displays for both the OMV and the TSR kit 

will Se optimally collocated. A nigh fidelity model of a 

composite target, from the TSR mission model assessment, will be 

produced. The computer simulation will include solid models 

with collision detection software to enable modeling of 

contacts.. A high fidelity model of the recovery systems will k 

built into the simulation software. 

1 -7 
A series of recovery scenarios wi 11 be coiducteh usi ng varying 

target model tumble orientations and rates. The target center 

of mass will be varied to challenge the operator(s) ability to 

determi ne the position of the spin axi s. 

initial conditions will be varied to provide alternative 

approach trajectories to challenge spin ax1 s position 

identification and spin axis aligrment by the operator during 

transi t. 

rates wi 11 support detenni nati on of operator 15 mi tati ons i n 

dealing with multi-axis spin, appendage avoidance, and high spin 

rates. 

Recovery scenario 

Vari ati ons in target tumble/spin orientation and spi n 

A second phase of TSR operator control capability assessment 

will involve development of a hardware model to conduct similar 

tests. The hardware model recornended in Paragraph 1.4 of this 

volume will be designed to accommodate this category of testing. 

One of the benefits to be derived from hardware simulation, over 

softwan! simulation, is that the operator receives a more 

realistic view of what will be present in an actual recovery 

mission. In addition, observers can be placed in different 

positions to oversee the operation, and they would have an 

improved, realistic view of the test and exercises. 

with the use of load cell arrays, the test team can measure . 

forc2s, view (and calculate and display for the operator) actual 

relative displacements and more accurately respond to the 

reactions created by the contacts betseen target and recovery 

sy stem. 

Finally, 

In this two-phase test Series, a numDer of Rcovery system 

operations assessments will also be conducted, 

will & designed to enable assessment of mission operations 

timelines, of propellant usage rates and despin/stabilization 

rates and time requi red to complete the various operations. 

potential for plume impingement on the target exists and thus 

will be modeled and evaluated. Another operations related 

recovery issue pertains to grapple mechanism positioning error. 

The existence of various levels of OMV deadband (accuracy within 

The experiment 

The 

1-8 
OMV operator 411, pitch and yaw capabilities) c;n be modeled 

and introduced in both the computer graphic and hardware 

simulation assessment tests. These simulation setups can be 

later expanded and used for continuing concept evaluation and 

eventually for operator trai ni ng. 

Phase 1 - Software Simulations 

Resource Reaui mments 

1) Manpower - Manpower estimate is 12 man months if done at MMC 

with exi sting hardware and software. 

2) Specialized Facilities - Facilities exist. 

3) Funding - Funding estimate is 12 man months of direct 

engineering labor at $100,000 and $10,000 in computer costs. 

Target Schedule - The required analysis is schedule constrained. 

Estimated duration of the- analysis is 8 months. 

Phase 2 - Hardware Simulations 

E) Resource Requi rements 

1 ) Manpower - Manpower estimate is 12 man months. 

2) Specialized Facilities - Facilities exist at MSFC and MMC. 

Hardware and software developed in recommended Task 1.4 would be 

used for this analysis. 

3) Funding - Funding is estimated at 12 man months of direct 

engineering labor, at $100,000 and $10,000 in computer costs. 

F) Target Schedule - The required analysis is scnedule constrained. It 

would be initiated following completion of hardware/software 

simulation system developed in Task 1.4, and would be completed in 

eight months. 

1-9