a summary from gemini flights gta 9, 10, 11, and 12

- - X-507-67-197

GROUND TRACKING RELIABILITY - A SUMMARY FROM GEMINI FLIGHTS

GTA 9, 10, 11, AND 12

FORD KALIL

MAY 1967

GODDARD SPACE FLIGHT CENTER GREENBELT, MARYLAND

0 (THRU)

6

X-50 7-67-197

GROUND TRACKING RELIABILITY - A SUMMARY FROM GEMINI FLIGHTS

GTA 9, 10, 11, AND 12

bY Ford Kalil

May 1967

GODDARD SPACE FLIGHT CENTER Greenbelt, Maryland

I

ABSTRACT

This report contains data, in both tabular and graphical form, regarding the reliability of the ground network as configured for support of Gemini, in particular the down-times of the various network functions such as: acquisition, radar range, radar angles, timing , telemetry, commands , spacecraft communication (voice) , on-site computer, NASCOM teletype and high speed data. The down times reported a re only those which occurred during Gemini flights GTA-9, 10 , 11, and 12; i .e . , launch to splash. The down time is that time from when the function was reported "red" until it was reported "green. " The percent of time down for these various functions varied from 0.04% for the NASCOM teletype to 4.8% for the C-Band radar ranging function. (See Table Vm).

This work was done in response to the Apollo Navigation Working Group (ANWG) action item (minutes of the February 23-24 ANWG Meeting) regarding data on the ground network failure modes, for use in evaluating the ground network capabilities, including contin- gencies, for support of Apollo.

iii

TABLE O F CONTENTS

ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . LIST OF TABLES . . . . . . . . . . . . . . . . . . . . .

LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . I . SUMMARY OF RESULTS . . . . . . . . . . . . . . . . . .

I1 . INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . III . PURPOSE . . . . . . . . . . . . . . . . . . . . . . . . . IV . GEMINI GROUND SYSTEMS RELIABILITY DATA . . . . . . V . ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . .

VI . REFERENCES . . . . . . . . . . . . . . . . . . . . . . . TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . FIGURES . . . . . . . . . . . . . . . . . . . . . . . . .

Page

iii

vi

vii

1

1

2

2

3

4

5

13

V

LIST OF TABLES

Page

I. Summary of Number of Ground System Failures and Total Down Time (hours) during Gemini Flights GTA-9/9A, 10, 11, and12. . . . . . . . . . . . . . . . . . . . . . . . . 5

11. Summary of Capabilities at Network Stations (Gemini Support) . . . . . . . . . . . . . . . . . . . . . . 6

111. Flight Times for GTA-9, 10, 11, and 12 . . . . . . . . . . . 7

IV. Gemini Network Station Down Times during GTA-9/9A Mission (119 hours Flight Time) . . . . . . . . . . . . . . . 8

V. Gemini Network Station Down Times during GTA-10 Mission (72.5 hours Flight Time) . . . . . . . . . . . . . . 9

VI. Gemini Network Station Down Times during GTA-11 Mission (72 hours Flight Time) . . . . . . . . . . . . . . . 1 0

VII. Gemini Network Station Down Times during GTA-12 Mission (96 hours Flight Time) . . . . . . . . . . . . . . . 11

VIII. Summary of Gemini Ground Systems Down Times in Percent of Mission Support Time for GTA-9, 10, 1 1 , a n d l Z . . . . . . . . . . . . . . . . . . . . . . . . . 1 2

vi

LIST OF FIGURES

Page

l a . Unnormalized Time between Failures Histogram for C-Band Radar Range Measurements during GTA-9, 10 , 11, and 12 Flights . . . . . . . . . . . . . . . . . . . . . . . . . . 13

l b . Unnormalized Down Time Histogram for C-Band Radar Range Measurements during GTA-9, 1 0 , 11, and 12 Flights. . . . . . 14

2. Normalized Down Time Histogram for C-Band Radar Range Measurements during GTA-9, 1 0 , 11, and 12 Flights. . . . . . 15

3 . Unnormalized Down Time Histogram fo r C-Band Radar Angle Measurements during GTA-9, 1 0 , 11, and 12 Flights. . . . . . 16

4. Normalized Down Time Histogram for C-Band Radar Angle Measurements during GTA-9, 1 0 , 11, and 12 Flights. . . . . . 17

5. Normalized Down Time Histogram fo r Acquisition Aids during GTA-9, 1 0 , 11, and 12 Flights . . . . . . . . . . . . 18

6. Normalized Down Time Histogram fo r Station Timing Standard during GTA-9, 10, 11, and 12 Flights . . . . . . . . . . . . 19

7. Normalized Down Time Histogram for Down Link Telemetry Ground Systems during GTA-9, 10, 11, and 12 Flights . . . . . 20

8. Normalized Down Time Histogram for Ground Up-Link Command Systems during GTA-9, 1 0 , 11, and 12 Flights . . . . 2 1

9. Normalized Down Time Histogram fo r On-Site 1218 Computer during GTA-9, 1 0 , 11, and 12 Flights . . . . . . . . . . . . 22

10. Normalized Down Time Histogram fo r Ground Spacecraft Com- munications Systems (Ground Up-Link Voice) , during GTA-9, 10, 11, and 12 Flights . . . . . . . . . . . . . . . . . . . 23

11. Normalized Down Time Histogram fo r NASCOM Teletype Systems during GTA-9, 10, 11, and 12 Flights . . . . . . . . 24

12. Normalized Down Time Histogram fo r NASCOM High Speed Data Systems during GTA-9, 10 , 11, and 12 Flights . . . . . . 25

vii

i -

I. SUMMARY O F RESULTS

The down time histograms indicate a Poisson type distribution for the various functions of interest . The functions o r systems which a re of interest from a navigation viewpoint and the percentage of time these functions were down, i. e . , inoperable, during the Gemini flights GTA-9/9A, 10, 11, and 12 a re as follows:

1.

2.

3.

4.

5.

6.

7 .

8.

9.

Acquisition, 3.7%

Radar range (C-Band) , 4.8%

Radar angles (C-Band), 0.23%

Timing, 0.21%

Telemetry (Down-Link) , 2.5%

Command (Up-Link), 0.65%

Spacecraft Communications (Voice) , 2.4%

On-Site Computers, 0.20%

NASCOM (Ground communications) , 0.041% for TTY , and 3.1% for HSD .

The down time histograms and other data a r e presented herein for only the time during spacecraft flight and thus represents the network at its peak performance, because prior to flight, the network is being "peaked" up via brief and detailed systems tests, and weak o r bad "components" a re replaced in order to bring the stations to peak operating condition for support of the flight.

II. INTRODUCTION

In the Apollo Program Directive No. 17 of March 31, 1966, "Apollo Navi- gation Working Group (ANWG) , the responsibility of providing information and recommendations concerning the individual and/or combined utilization of Apollo tracking and navigation systems

(ref. l), it states that the ANWG. . . "is assigned

to best perform the Apollo mission. ' I In order to coinply with this directive, extensive analysis of the navigational capabilities of the Manned Space Flight Network (MSFN) have been performed by the ANWG (see refs . 2 and 3 ) . In that work, it was assunied all tracking functions of the XlSFN stations a re operational 1005[ of the time. be tdieli which takes into account various tracking function failures.

For future analyses, a more realistic approach may need to

Although there is prescntly very little data based on flight experience about the reliability of the Unified S-Band Systems (USBS), there is significant data from the Geniini missions and that data is presented herein.

Steps have been taken to obtain in the future the desired reliability data regarding the USBS via the equipment logs which have been modified to include the requirements of the ANWG. The equipment logs a rc reported, signed by each system o r subsystem supervisor at the si tes, and submitted to GSFC on a weekly basis during non-mission status and daily during niission status, (see ref . 4) .

111. PURPOSE

The purpose of this report is to present the ground systems reliability data: primarily the down times, and number of failures as obtained from refcrenccs 5, 6 , 7, and 8 for Project Gemini, during the flights GTA-9, 10, 11, and 12.

IV . GEMINI GROUND SYSTEMS RELIABILITY DATA

A suiiimary of the nuinber of failures and the total down time for those failures which occurred during thc flights of Gemini missions GTA-9, 10, 11, and 1 2 is given in Table I for each station and each subsystem o r function. ground station capabilities and the flight t imes for these missions a r c given in Tables I1 and 111, respectively.

The

A listing of the down times fo r each failure according to subsystem is given in Tablcs IV, V, VI, and VII for Gemini missions GTA-9, 10, 11, and 1 2 , rc- spcctivcly. The down tinics from all these niissions a re also plotted i n histogram form in Figures 1 through 10, for each subsJrstem in ordcr to sho\v the down tinic distribution. The normalized down time shown is thc down tinic per mission support hour; where the mission support hour is the product of the total

2

flight time for the four missions being considered t imes the number of subsys- tems o r systems in the network which had to be ' h ~ p ' ~ for support of these missions.

In the case of the C-band radars , thc failures a re presented here for the range measurement and angle measurement functions independently. References 5 and 8 did not always distinguish between range and angle failures. Unless a failure was identified as an angular failure, i t was assumed to be a range failure. Furthermore, i f the radar was not identified, it was assumed to be a C-Band radar .

The dolt7n times reported are the times from when a system o r function w a s reported rrredtr until it was reported "green" by the site. This means that the down time includes the time to diagnose the failure, obtain parts o r spares as necessary, correct o r repair , and "check-out" the function. In order to be conservative, the down times shown herein a re the largest of the down times reported via the: (a) station status reports, (b) equipment log, and (c) the network controller's report ( see ref. 8 for example).

In the case of the range measurement function, a time between failures histogram is also shown in Figure l a , in addition to the dow-n time histogram shown in Figure lb . The time between failures for the other systems or functions is not presented at this time, but will be reported in subsequent revisions. In the case of the first failure, the time between failure is in reality the time to failure from the start of terminal count.

V. ACKNOWLEDGEMENTS

In this undertaking it was necessary to contact and work in close cooperation with many people. I would like to take this opportunity to thank these people for their helpful suggestions, comments, and cooperation, in particular, H. W. Wood, J . Donegan, R. Liebermann, F. Kallmeyer, W. E . Laumann, A . Hampton, and J . Cook.

3

VI . REFERENCES

1, Phillips, S. R. , "Apollo Navigatior, Working Group, Apollo Program Directive No. 17, March 31, 1966.

2 . MSC-GSFC, ANWG Technical Report No. AN-1.2, "Apollo Missions and Navigation System Characteristics, I ' January 17, 1967.

3. MSC-GSFC, ANWG Technical Report No. AN-2.1, "Apollo Navigation - Ground and Onboard Capabilities , September 1, 1966.

4. "Network Operations Directive for NASA Manned Space Flight Operations, contact Manned Flight Operations Branch, Goddard Space Flight Center, November 1, 1966.

5. "Network Performance Analysis for the Gemini GTA-9/9A Mission, approved by H. W. Wood, Manned Flight Operations Branch, GSFC, Re- port No. X-552-66-438, December 23, 1966.

6. I'Network Performance Analysis for the Gemini GTA-10 Mission, approved by H. W. Wood: hlanncd Flight Operations Branch, GSFC, Report No. X-552-66-589, December 28, 1966.

7. "Network Performance Analysis for the Gemini GTA-11 Mission, approved by H . W. Wood, Manned Flight Operations Branch, GSFC, Report No. X-552-66-590, December 29, 1966.

8. "Network Performance Analysis for the Gemini GTA-12 Mission, approved by H. W. Wood, Manned Flight Operations Branch, GSFC, Report No. X-552-67-36, February 1967.

Table I Summary of Number of Ground System Failures and Total Down Times (hours)

during Gemini Flights GTA-9/9A, 10, 11, and 12 (See Tables IV, V, VI, and VI1 for down times during each mission.)

Number of Fa i lu redTo ta l Down Time, Hours (1) TOTALS

NA NA 0.5

System

Station Acq. Aid

- 1/24

C-Band Radar s "mmand S/C Cam. &-Site up-Link Up-Link 1218 I Voice 1 Computer

Timing Telemetry itandard Down-Link

Range ' MCC-K -~ 1 _~ MLA

CNV

3-e NA

1/0.5 ~

IF. 5

6/11.5

NA NA I NA I 1 I 0.75 I

3/6.0

NA __ - -

V 8 . 0

U8.5 ~~ - t

NA .- __ ~

NA

1/90.0

1/12.0

_~

~~~

2/6.5 21'4.0 :I; _~ --

KNO

PRE

TAN

CRO

WOM

CTN

HAW

CAL

GYM WHS

TEX

EGL

SHIPS

TOTAL FAILURES

Total m w n Time, h r s

Avg. No. of "Systems" (2)

~ _ _ _ ~ -__ ~

-~ __

-

-__ ~ _ -

-~ ~_

-- --

- -__ - i

_ _ _

~

__

___

v 0 . 5

__ ~

1/5.0 ~

2/12. c 1/0.25 ~~

~

1 / 0 . 7 5 1 % 3/11.0 _NAP

1/3.0

_. . .~

3/11.0 3/4.75 1/1.75 ~- _ _ _

2/5.5 2/6.0

1/1.5

8/28. 7E

3/7.0

._ -

~

-I* 3 194.0 t- 1/96. C

~

1/96. a - 11

239.75

- 2/97.5

1/:.5

f 1:O

2/5.5

33 6

1 294.25 14.0

~

17

16.75 I 159.5 ' 18 17 _"i

0.88

Mission Support T i m e in hour s (3) c % of T i m e Down

6500 6140 6140 __

0.23 3.7

1.7

~

- 4.8

5.4 I Failures/ 1000 hrs ( 0.98

(1) Down Time is the time from when a function o r system was reported "red" until it was reported "green" at a given station.

(2) Avg. No. of "Systems" =Average number of statlons with the given capability and called on for support during the GTA-9/9A, 10, 11, and 1 2 missions. because the network configuration varied from fhght to flight, partlcularly in the ship's support.

(3) Mission Support Time = Total flight time of 360.5 hrs for GTA-9/9A. 10. 11, and 12 missions multiplied by the average number of "Systems."

(4) No. of Failures per 1000 mission support hours, rounded off to two significant figures.

5

Table II Summary of Capabilities a t Network Stations

(Gemini Support)

Cape Kennedy (CNV) and Mission Control Center ( MCC -K)

Grand Bahama Island (GBI)

Grand Turk Island (GTK)

Bermuda (BDA) Antigua (ANT) when

Canary Island (CYI)

Ascension Island (ASC)

&no (m0) Pretoria (PRE)

coordinated

~~

when coordinated

Tananarive (TAN) Carnarvon (CRO) Wooniera (WOM) when

coordinated __ ~~ ~~

Canton Island (CTN) Hawaii (HAW) Cal i fornia (CAL)

Guaymas (GYM) White Sands (WHS) T e x a s (TEX)

Eglin (EGL) Wallops (WLP) Coas t a l Sentry Quebec

Wheeling ( W E )

Rose Knot Victor (RKV) Goddard Space Flight

M e r r i t Island (MLA) P a t r i c k A. F. Base (PAT)

~

~ ~~

(CSQ)

_ _ _ ~

Cente r (GSFC)

TOTAL W/SHIPS3

Through Cape Kennedy Opera

-

4 c .d 2 '3 4 z -

X

X X

X

X

X

~~

X X

X

X X X

X X X

X X

X X

X

20 -

-

s

2 2

!

ii! -

X

X X

X

X X

X

X ~

X

X

X X

X X X

X X

X

X X

1: -

-

4 3 e

P4 -

X

X X

X

X X

X

X

X

X

X

X

X

1: -

-

2 2 V

3 h -

X

X X

X

X X

X X

~

X X

X X X

X

X

X X

X

~

X

- - . .~

S-Band Radnr 2 'rraining only

The totals used in subsequent tables or figures may mission, in particular, in the ship support.

- w

E

E 9

r \

3 2 -I

4 -

X

X

X

X X

X X

~

X X

X X X

X

X

X X

X

X

1f -

-

(II

2 8 8

4 8 5

,, h

-

X

X

X

X

X

X

X

X

X

-

ET g 2 5 2 z g

5 9 -

N

E E

N

E N

E N E

N N

N

N N N

N N N

N N

N N

N

E E

23

X X

X X X

X

X ~

X

X X

X ~~

X

18

-

3 i: -

K

t t

X

c X

* X X

X X

X

X X X

X X X

X X

X X

X

X

~

-

differ because the network configuration

6

-

a, a h * * 2 -

X

X X

X

X

X

X X

X

X X X

X X X

X X

X X

X

X

~~

~~

21 -

-

E V h a,

3 -

X

X X

X

X X

X X X

X X

X

X X X

X X X

X X

X X

X

X

-

varied from mission to

-

x) r(

N rl

h a,

a

V

*

E -

2

X

X

X

X

X

X ~

X X

X

1( -

Mission

GTA-9

GTA-10

GTA-11

GTA-12

Table I11

Flight Times for GTA-9, 10, 11, and 12

Launch Date-GMT

6-1-66 15 :00

6-3-66 13 :40

7-18-66 20:40

7-18-66 22:20

9-12-66 13 :05

9-12-66 14 :42

11-9-66

11-11-66 19:08

11-11-66 20:47

Vehicle

Agena

Gemini

Agena

Gemini

Agena

Gemini

Agena & Gemini

Agena

Gemini

Splash Date-GM T

6-6-66 14:Ol

7-21-66 21:07

9-15-66 1 4 : O O

Postponed

11-15-66 19:21

Vehicle

Gemini

Gemini

Gemini

Gemini

Flight Time, Agena Launch

to Gemini Splash, Hours

119.0

72.5

73.0

96.0

7

z z

L % d

12 t I

id 'E

i f

8

< I 111 I 1 t I

L

9

0

N

0

m

1 0

f U U z z I E

88 2s z - E 8g %i- z

11

Table VIII

Summary of Gemini Ground Systems Down Times in Percent of Mission Support Time*

for GTA-9, 10, 11, and 12 (Total Flight Time = 361 hours)

System o r Function

Acquisition

C-Band Radar:

=wP Angles

Timing Standard ~

Telemetry (Down-Link)

Command (Up-Link) ~

Voice (Up-Link)

On-Site Computer (1218)

NASCOM

TTY

HSD

% of Time Down During Manned Space Flight

~~

3.7

4.8

0.23

0.21

2.5

0.65

2.4

0.20

0.041

3.1

*The Down Time is the time from when a function or system was reported "red" until i t was reported "green" at a given station. TO be conservative, the down times shown are the largest of the down times reported (See refs. 5. 6 , 7 , 8 ) . The mission support time is the product of the total flight time from Agena launch to Gemini splash and the number of ground systems.

12

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a summary from gemini flights gta 9, 10, 11, and 12

Documents

Transcript of a summary from gemini flights gta 9, 10, 11, and 12