m ~ G I N E E R I N G m o 1240-540-6~ ' .- *

May 14, 1963 - 4

MINUTES OF FUUY4.R REQUI ,A ' COORDINATION MEETING #I

BETWEEN

GRUMMAN AIRCRAFT ENGINEERING CORPORATION (GAEC)

AND

MASSACHUSETTS INSTITITTE OF TECHNOLOGY (MIT)

N79-76 5 22

-

, . . - u m n - ~ - 116630) REQUIREMENTS CUORI BETWEEN GRrJMM_91 A 3

- - - - D NUMBER) (CATEGORY)

I ' Erick Stern Cvcfomc Ann 1 v n i s -

'CUSSIFSCATION CHAN(zE

UNCLASSIFIED r , .

A),/ //&fl.G Ta, / /

By authority Changed by Classified Document Mas& Control Statiok, NASA Scientific and Technical Information Faolllty

-. Date /& L3(/2 2/

ZJIBfiH2L Arnold B . Whitaker rn Systems Project Engineer, GAEC

- .

NOTE: These Minutes do not const i tute contract change authorization. Changes having an e f fec t upon the provisions of e i the r the GAEC or MIT contract must be separately negotiated w i t h and authorized by the NASA Contracting Officer d- h i s designee.

LIST OF ATTENDEES:

R. Lewis - ASP He TOY - STD Pa Cramer - FCOD

M. Traegeser N. Sears P. Felleman W. Tanner J. Dahlen

J. C. T. A. R. K. J. G.

Gavin W. Rathke J. K e l l y B. Whitalrer Carbee Speiser Cook Sullivan

S o C h o w No Oletad To H a g g c r t y Go Scheucrlein J. Green W. Schoen

R. Peters E. Stern

J. ROth

Meeting No. Date

2

Agenda

Backup Guidance Design Concepts

Proposed Rendezvous Technique

Gimbaled VS. Fixed Antenna Comparison

Mission

Hardware

Reliability

Proposed Radar Configuration

Result8 of Altimeter Utilization Study

Results of Mid-course Guidance Study

Results of Homing Rendezvous Study

Radar Requirements Summary

Radar System Tradeoff Factors

Justification of Selected Implementation

Weight and Power Summary

Summarization

Discussion of Radar Requirements

E. Stern n

N

J. Greene It

N

A. Whitaker

General :

E. Stern made the i n i t i a l presentation covering backup guidance and rendezvous concepts, resu l t s of studies t o es tabl ish radar requirements and a summary o f such requirements as generated by both primary and backup Navigation and Guidance (aG) considerations. Design Concepts a re shown i n Figures 1 & 2. proposed by GAEC is i l l u s t r a t ed In Figures 3-8. A comparison of gimbaled versus fixed antenna configurations w i t h respect t o mission requirements, hardware implications and system re l i ab i l i t y is shown i n Figures 9-14. The radar system configurations proposed i s shown i n Figure 15. the preliminary resu l t s of a study aimed at establishing the f e a s i b i l i t y of u t i l i z ing only radar alt imetry data f o r IMU updating during the terminal descent phase. yield sat isfactory resul ts . correction and rendezvous homing studies. summary as mutually agreed upon by MIT and GAEC.

The basic Backup Guidance The Rendezvous Technique

Figure 16 gives

Results obtained so far indicate t h a t t h i s procedure w i l l Figures 17-25 present the resu l t s of mid-course

Table I is the radar requirements

J. Green gave the second presentation concerning the hardware imple- mentation of the proposed radar system. are shown i n Figures 27-28, implementation scheme i s based a re given i n Figures 29-33. scheme tradeoffs a r e presented as Enclosure I.

The tradeoff fac tors considered The eonsiderationo QP which the proposed

Modulation

Figures 34-36 indicate the weight and power requirements of the LEM radar system based on data from several manufacturerswho submitted pro- posals f o r radars t o satisfy assumed LEM requirements. normalized t o be compatible w i t h the requirements of Figures 30 and 31.

This data was

During the summarization (by A. Whitaker) and discussion following the formal presentation, a number of e~nclusions and agreements were reached. N. Sears has prepared a se t of' tBb3.es and diagrms outlining MIT's concepts on radar u t i l i za t ion and requirements (Figures 36-44) and these were discussed i n some de ta i l . Figure 26 was generated as a resu l t of these discussions. It was agreed that the range accumey of the rendezvous radar would remain at 1$ + 5 f t . as specified by GAEC, unless a penalty i n weight o r power i s associTted with achieving t h i s tolerance, i n which case it could be relaxed t o 1.58 + 30 f t . The specification of fixed and random boresight e r rors of the rend<zvous radar of 1 5 m r and 3 m r respectively (3) represents a compromise between t h e GAEC specification of 9 m r t o t a l and the IMIT requirements of 20 m r f ixed and 6 m r random.

As far as the doppler altimeter is concerned, the a l t i t ude range was agreed t o be specified as 70,000 feet , unless the time interval betweeen reading t h i s a l t i t ude and attaining pericynthion (nominal descent inject ion point) is inadequate t o properly check out the radar. be accomodated by the doppber altimeter is as yet undermined, but it was

The range of VH t o

Meeting Date m3e

NO

agreed tha t 200 fps I s a typical value at which the specified accuracy i s t o be at ta ined and tha t 5000 fps i s a desirable range which would allow complete checkout of a l l three beams of the radar p r io r t o i n i t i a t i o n of powered descent.

.

/ NIT proposed t h a t the rendezvous radar be capable of being slaved t o the OM, and vice versa, t o allow visual acquisit ion and visual monitoring as w e l l as t o minimize angular readout equipmento This concept imposes cer ta in a t t i t ude and location constraints on the radar, but these, w i t h the one exception discussed below, do not appear insurmountable. basic approach seems reasonable and of fers some a t t r ac t ive features and GAEC -agreed t o provide t h i s capability.

The

In several instances, the GAEC and MIT viewpoints could not be These involved primarily the primary and backup rendezvous procedures. contrast t o the technique outlined i n Figures 3-8, MIT proposed a completely automatic rendezvous operation consisting of a ser ies of long range m i d - 'course corrections,an i n i t i a l high-thrust pre-computed th rus t phase t o within 5 n.mi* and 100 fps re la t ive velocity, and a f i n a l (high th rus t )

i phase t o docking in i t i a t iono GAEC f e e l s that the automatic mode should be compatible w i t h the manual male t o germit crew monitoring and merride.

Another basic difference of viewpoint involves the backup procedures. HIT considers the first t i e r backup mode t o be centered i n the CSM (CSM tracking radar inputs t o t h e AGC result ing i n LElM guidance commands trans- mitted t o LEM f o r execution v ia the vsiea communication l ink) . proposes tha t the homing technique described be considered a manual a l te rna te t o the primary automatie mode, and, i n the event of a non-radar I

C, f a i l u r e i n the primary N&G system, t h a t it become the logical back-up mode. I t Apparently, fur ther resolution by N a A o S o A o , is required, since De Gilberts' I memo of 3/1/63 en t i t l ed "Guidance Radar Requirements" is subject t o multiple i

In r !

( GAEC 1

-I ' interpretations. -A. e--

One i t e m of discussion involved the poss ib i l i ty of using the existing C-band transponder on the CSM instead of a separate X-band transponder. The poss ib i l i t y of providing interferometer type rendezvous radar instead of a gimbaled antenna radar was also b r i e f ly mentioned. HIT f e e l s that such an approach would result i n a hardware implementation comparable i n f l e x i b i l i t y t o a fixed antenna radar and tha t i f a interferometer i s seriously considered, the fixed antenna approach should be re-examined.

A s far as radar mounting is concerned, MIT suggests tha t the radar be mounted on the navigation base i n order t o reduce angular misalignment of the radar boresight axis re la t ive to the coordinate system of the IMU and OMU. LEU pressure shell . absolutely necessary, since it i s considered essent ia l not t o compromise the in t eg r i ty of the pressure veesel. approach

This would require tha t the radar mounting s t ructure pierce t h e GAEC would avoid t h i s unless it can be shown t o be

KIT agreed t h a t t h i s was a reasonable

Meeting No. Date w3e 5

The action items generated at the meeting were:

1. The penalty involved i n specifying 1% + 5 f t . range accuracy f o r the rendezvous radar was t o be invTstigated by GAEC.

2. The adequacy of 70,000 ft. a l t i t ude range f o r the doppler altimeter, i n terms of checkout capabili ty was t o be established by GAEC.

3. The upper l i m i t of VH capabili ty i n the coppler-altimeter w a s t o be determined jo in t ly by MIT and GAEC.

GAEC LMO-540-61 May 14, 1963

i

Distribution L i s t MSC (J. L. Decker) - 14 copies

RASPO, Bethpage NASA, MSA, OMSF, Washington, D.C. - 6 copies

A t t : M r . J . Disher

MIT, I L , Cambridge, Mass. A t t : M r . M. Trageser

Mr. N . Sears Mr. P. Felleman Mr. W . Janner Mr. J . Dahlen

MIT, IL , RASPO - 1 COPY

NAA, Downey, Calif - 1 copy A t t : Mr. R . Berry

RASPO, NAA - 1 COPY

J. B-aton, GAEC Office, Houston, Texas J. G . Gavin R. S. Mullaney C . W . Rathke/T. J . Kelly A. B ... . m i t a k e r R . M . Carbee E . Stern P. Gardner/R. Inman G . Henderson J . Green J . Roth R . F l e i s ig K . Speiser J . Cook G . Sullivan LE24 Project F i l e Data Management

A - Radar Altimeter

Quantity

Alt i tude (h)

Alt i tude rate (A) Horizontal Velocity

Posi t ion 3

B - Rendezvous Radar

Quantity

Range (4 Range rate (G) Angle (e)

Angle Rate (4%) 4

1

M a x i m u m

70,000 f t o

500 f p s

2,000 f p s 2

50'

Maximum

400 N. M i .

+ 4800 fps. -

+ 15 mr/sec. -

1. 3FValues.

2. 5000 fps design objective.

Minimum Typical Accuracx

5 f t . 20,000 ft. 1s - + 5 ft.

1 fps. -- 1% - + 1 fps.

1 fps. -- 1s - + 1. fps.

O0 -- 20 m r .

Minimum -322s Accuracy

500 f t . 9-0.2 N*M* I$_+ 5 ft.

1 fps. 200-1000 fps. 1.06 - + 1 fps.

-- -- 15 mr. bias 3 m c random

0.2 mr/sec. -- 0.2 mr/sec=

3- Angle of axis of symmetry w i t h respect t o X axis.

4. Not required by Primary Guidance.

Table 1

GUIDANCE DESIGN CONCEPTS -

A U MANUAL MODES WHERE INCORP- oRATlON INCR€AS€S CREW WFUY

DR€CT S€NSORDISPCAY FOR MANUAL M O M S 0MKW SIMPUR # MOR€ R€LIABL& THAN PRlMARY MOD& AOTOMAZIC MOWS COMPATIBLE WlTH MONUAC MONITORlNG AND OV€RlVE WU€N MANUAL MODES ARE PROVID€O

1

J - 4

BACKUP GUIDANCE --- -. DESIGN CONCEmS

I - ,

RENDEZVOUS CONCEPTS

CREW CAN PEWORM VISUALLY COU!RS€CORRECT/ON TO OBTAIN COU/S~Off COU!S&

RANGE6 RANGE RATE ESTI- MATES MAY'&POSS/BL.E

CREW CAN RENDEZVOUS MANUALLY WITH DISPLAYOF- -J

mmr/oN OFLOS LOS RATE /a /NERTIAL COORD. RANGE RANGE RATE

RENDEZVOUS CONCEPTS kCOIUJ3

MARUAL CONTROL FUNCTIONS OR/flNT VEHICLE Z-AXIS

PARALEL TO LO8 OR/€NT X - A X I S TO PLANE OFLOS RAT€

MULL LOS RATE ADJUST RANG€ RATE AS A FUNCT/ON O f RANG€

U

-\ . __ I400

RENDEZVOUS MANEUVER

U I

- MANUAL-VISUAL RENDEZVOUS TECHNIWE

I

a’ L G >- I- -

REN DEZV~ELO~I NG VELOCITY VS. TIME

32C

28C

24C

2a

4c

0

VARIATION I N lNKIAL CLOSING VELOCITY

\ 4

TRACKING RADAR DISPLAYS FOR RENDEZVOUS

I

GIMBALED vs. FRED ANTENNA SYSTEM UTILI/. STUDIES

POWER , PHASE lDESC€NT(ABORT

RAVAR UTILI

O n E R

CONS7R.

TRACK mcoN

TVC

VIS MOM OF

LAND- MARKS

-

A W l R € C 'TRACK CSM

7VC

MID-C., REND, 4 DOCK

TRACK C-SM

MON C-SM W I W SCAN

K E S . &

UNA10

\

\ \ /

I' I I

0

\ \

\

H/TH A 8EACON 1

I I I I I I I

I

r I

I 1 I

GIMBALED vs FIXED ANTENNA HARDWARE TRADE - OFFS

GIMB

E A M W / V W , deq. 4

I

32 ANG. RES,, mv ( 3 a ) 3

FI%ED

10 17 8

7,5

31 28

EXPERIENCE. FACTOR GIMMC€P: CARGG€ S€&€CTION OF QUAL

- GIMBALEO VS FIXED ANT, RADAR

RELIABILITY TRADEOFF

A. G I M W D - - Rp, 09929

0.9988

0.9939

- PROPOSED RADM CONFIGURATION

1. RADAR ALTIMETER 3-BBIM DOPPLER

2. RENDEZVOUS RADAR

R€L. COORDS.

- VARIATIONS IN FINAL V PARAMETERS

DOUBLE-SLOPE SURFACES *!!!I t, 2 sum

SCOPE APPEARS, SEC 12 22 4'1 72 82 92

V V

-1.26 0.02

-1.09 -0.01 -2.23 -3.67

VI"

8.63 2.38 7. 23 5.60 8.09

13.85

2307.6 2306.4 2299.9 2300.4 2269.1 2295.2

*NOM. t OF FlX FOR FWAC V&'SC.=:t12 S€C

2-4 20

,

RADAR UTILIZATION ANAlYSIS

ASC€NT ANT) RENDEZVOUS @ USE OF TRACUINO ‘RADAR DURING

m m Y - * F A S . OF MIV~COURSF CORRFCtlONS

n/ON-MOM/A/O PENvE2vous W/T#

La04 RA7E ACCURACY vs AV BACK-UP GUIDANCE

?€NACTY FOR UOMINO REIVPE2. AN7: PlAC€M’T: VEPCOYMIT PRO%’$

UT. €NV. CONSTR, VIS, €FFECTS,EjC. COMI;! W T , COMPLEXITY i PEtlRB.

OF FUEV vsb GIMBAllEV ANT: UAROWAPE TRADE-OFFS ‘TO

VETERMINE RAVAP IMPCEMENT.

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4% /v 4 V 4

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100 T4RUS 7- /NCR€ASE

3%

I I 1 IK 2K 3K

TIM€, SEC

too

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1

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4,290 F T

1.00 2.02 3808 1.00 2#38

1 .1

3 (0%

2.83

2. re

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V€Rl SEP, N. MI.

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400

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RADAR DESIGN GROUND RULES

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2.7 R,

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0.5 2 4

9.3

39.6 200 8-5

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8300

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2.25

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2.5

YES

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