The benefits of the standardized hardware included in the Get Away Special (GAS) space shuttle payloads are discussed. Payload requirements within the GAS program are summarized

Schmitt, G.

English

NASA Technical Reports Server

MODULAR AND STANDARDIZED GAS PAYLOAD HARDWARE 
Guen ter Schmi tt 
Rayser-Threde GmbH 
Munich, FRG 
Objec t ives  : 
Numerous payloads have been carried o u t  w i th in  NASA's GAS 
program i n  t h e  p a s t  and much more w i l l  be flown i n  t h e  fu tu re .  
Therefore,  bes ides  t h e  e x i s t i n g  NASA GAS hardware, only modu- 
l a r  and s tandard ized  payload hardware w i l l  lead t o  a reliable,  
cost e f f i c i e n t  experimental  platform w i t h  s h o r t  t u r n  around 
t i m e s .  
E f f o r t  should be concentrated on sc ience  and experiments and 
n o t  t o  much spend with s tandard  s e r v i c e  systems and related 
l 
paperwork e 
Payload requirements: 
Common payload requirements wi th in  t h e  GAS program can be 
summarized t o  
- economic use of a v a i l a b l e  space and payload weight 
capac i ty  
- adequate power sources  
- v a r i a b l e  payload t iming and c o n t r o l  including t h e  GAS 
t y p i c a l  t h r e e  on-off commands 
- f l e x i b l e  housekeeping, data a c q u i s i t i o n  and recording 
sys  t e m s  
- s tandard ized  ground support  equipment 
All on board systems have to  be capable t o  surv ive  v i b r a t i o n  
and mission related temperature environment. 
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https://ntrs.nasa.gov/search.jsp?R=19840019697 2020-03-22T09:34:59+00:00Z
Standard payload s e r v i c e  systems: 
The design concepts for  s tandard  payload service systems are 
based on t h e  common payload requirements. 
Bas i ca l ly  t w o  d i f f e r e n t  conf igura t ions  of experiment/pay- 
load  suppor t  s t r u c t u r e s  are e x i s t i n g :  one which uses  round 
decks, hard mounted t o  s t r u t s  ( f i g .  I ) ,  whi le  r ec t angu la r  
she lves  are a t t ached  t o  columns v i a  shock absorbers  with t h e  
o t h e r  ve r s ion  ( f i g .  2 ) .  This design al lows a more unique use 
of t h e  GAS space and weight c a p a c i t i e s ,  adequate i n f l i g h t  
load c a r r y i n g  c a p a b i l i t y  and a g e n t l e  environment f o r  t h e  
deckmounted hardware. 
(AS REQUIRED) 
EXPERIMENTS AND 
RACK TO BE 
SUPPLIED BY 
EXPERIMENTER 
Figure 1 
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INTERMEDIATE PLATE 
I 
TOP PLATE 
I + 
- 2  
FIGURE 2 
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A s  power source s i l v e r  z inc  batteries w e r e  chosen p r e s e n t l y  
r ep resen t ing  t h e  best compromise w i t h  r e s p e c t  t o  energy den- 
s i t y ,d i scha rge  characteristics, l i f e  t i m e ,  s e l f  discharge 
rate, handl ing and s a f e t y .  Some e f f o r t  is  involved w i t h  
p ressure  t i g h t  and sealed b a t t e r y  boxes, t h e  H2 outgass ing  
l i n e s ,  temperature monitoring and fus ing  as w e l l  as t h e  l o w  
vol tage  cut-off.  Fusing and l o w  vo l tage  cut-off c i r c u i t r y  and 
the  i n t e r f a c e  t o  the  GAS PPC i s  i n t e g r a t e d  i n t o  the s tandar-  
dized power la tch modules housed sepa ra t e ly  o u t s i d e  of the  
battery boxes . 
To provide v a r i a b l e  payload t iming and c o n t r o l  the  three 
GAS t y p i c a l  on-off commands may n o t  be s u f f i c i e n t  f o r  m o s t  
app l i ca t ions .  Therefore a microprocessor c o n t r o l l e d  and easily 
programmable sequencer w i t h  low power consumption (0,3 W )  w a s  
designed. Redundancy is incorporated by us ing  independend sub- 
rou t ines .  
Experiment and housekeeping data are acquired a t  a data rate 
of 5 kb i t / sec  by a 16 channel,  12 b i t  PCM system. 
The PCM system provides  12 analog and one d i g i t a l  channel fo r  
t h e  experiments, whi le  us ing  t w o  d i g i t a l  channels for  house- 
keeping data and one a d d i t i o n a l  for  record ing  experiment t i m e  
i n  minutes. A l l  data are stored on a NAGRA cassette t ape  re- 
corder  w i t h  a t o t a l  running t i m e  of approx.’ three hours and a 
s to rage  capac i ty  of approx. 56 Mbit. I f  opera ted  i n  an i n t e r m i t t e n t  
mode, recording data fo r  one second every minute covers  a 
t o t a l  payload ope ra t ion  t i m e  of approx. 120 hours. 
During i n t e g r a t i o n  and ground tests the  payload w i l l  be operated 
mostly by i ts  ground support  equipment which also a l l o w s  
record ing  and d i s p l a y  of payload PCM data stream. The ground 
support  equipment c o n s i s t s  of s tandard  power supply,  ba t t e ry  
s imula tor ,  NASA i n t e r f a c e  s imula tor ,  modular payload opera- 
t i o n  panel ,  d i sp l ay  u n i t ,  PCM decoder and an Apple personal  
computer w i t h  dua l  floppy d i s k  and monitor. A l l  components are 
mounted i n  t w o  portable racks. L a s t  minute access to  the pay- 
load is  provided even if it is  already i n s t a l l e d  i n t o  t h e  f l i g h t  
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c a n i s t e r .  The  payload can be completely operated via the  NASA 
i n t e r f a c e  connector wh i l e  s t a t u s  and data are monitored a t  t he  
same t i m e .  
Standard experiment faci l i t ies :  
Besides t he  payload service systems f l i g h t  proven experiment 
f a c i l i t i e s  are a v a i l a b l e  a t  Kayser Threde, too. 
For f l u i d  physics  experiments a He-N laser Doppler i n t e r -  
ferometer w i t h  an o p t i o n a l  s p l i t t e d  beam e x i s t s .  The laser 
ou tpu t  power is  0,5 mW. 
e 
Op t i ca l  observa t ion  can be done by a modified 24mm x 36mm 
photographic camera (Olympus) w i t h  a 250 p i c t u r e  f i l m  storage 
and a t i m e  d i s p l a y  onto each p i c t u r e  by a LED ar ray .  F i l m  
cameras w i l l  be a v a i l a b l e  a t  a l a te r  date. 
0 For thermal process ing  of probes up t o  500 C an isothermal, 
multipurpose furnace can be provided. The chamber i s  4 0  mm i n  
diameter and 160 mm i n  length.  
P l a n t  development can be carried o u t  i n  growth compartments 
furn ished  w i t h  temperature c o n t r o l ,  day/night s imula t ion  
as w e l l  as l i q u i d  s to rage  and i n j e c t i o n  devices. 
Summary: 
The use of modular and s tandard ized  GAS payload hardware has 
many advantages. 
Standard hardware minimizes t i m e  e f for t  and c o s t  for  design 
and q u a l i f i c a t i o n .  F l i g h t  proven hardware ensures  proper  
func t ion  and 
w i t h  respect 
r equ i  remen ts 
use r  as w e l l  
ope ra t ion  dur ing  mission. I t  demands less e f fo r t  
t o  t h e  prepara t ion  of the payload accommodation 
and the  s a f e t y  review data packages f o r  t h e  
as f o r  NASA. 
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Modular systems allow t o  be combined i n  order  t o  serve an 
enlarged number of experiments i f  t w o  GAS can i s t e r s  are in t e r -  
connected. 
These facts enable t h e  user  or  experimenter t o  concentrate  on 
the experiments and related science instead of spending t i m e  
i n  development of own hardware while  standard,  f l i g h t  proven 
systems are avai lable .  
Nevertheless, cos t  eff ic iency f o r  standard serv ice  systems 
encreases by each r e f l i g h t .  
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Mr. Richard N. Azar, through reserving three Get Away Special 
(GAS) containers, began the GAS program for El Paso, Texas. 
"Space is a challenge, always has been," Azar said, "The 
canisters offered us an opportunity to challenge young minds." 
Azar got the idea for participation in the space shuttle 
program in 1977 when he read a magazine article about the 
National Aeronautics and Space Administration's off.er to let 
private individuals send experimental projects into space aboard 
what was then called the ('space truck" Columbia, 
Azar contacted NASA and made a down payment of $500 each for 
three canisters. Each capsule has a price tag of $10,000. 
One canister was set aside for the twin cities of El Paso 
and Juarez, another for the University of Texas at El Paso and 
the third was designated for projects developed by high school 
students. 
The El Paso containers are numbered 3 3 ,  3 4 ,  and 35, and are 
grouped under the Education queue. El Paso Indepen,dent School 
District and the Ysleta Independent School District have 
deposited the necessary $9,500 with the El Paso Community 
Foundation to complete the funding for payload # 3 4 .  
The El Paso/Juarez Space Shuttle efforts began in late 1977 
to provide research bpportunities and interesting space related 
activities for the El Paso Area school systems. In the Fall of 
1982 more than 100 students in the local school districts 
participated in an advanced science seminar giving background on 
the project. Any student interested in the study of space and 
space activities was invited to prepare research and prepare an 
experiment in his or her field of interest. Twelve students from 
the El Paso area have developed scientifically worthwhile 
projects. These students will have the opportunity to send their 
experiments on board the NASA Space Shuttle in August of 1984. 
This experimental opportunity for students is an effort to 
motivate those interested to reach new horizons through spac>e 
research. Through planned activities, trips, contests, seminars, 
and speaker programs, thousands of El Paso students have become 
aware of what the future holds in space. They, too, have 
contributed valuable insight and questions to be asked. 
Expanding young minds is the greatest resource for mankind. 
This GAS payload consists of an Aluminum 6061 frame, with 
four shelves supporting the experiment hardware, the system 
controller and power supply. This frame was designed developed 
and tested by Farah Manufacturing and El Paso Natural Gas of El 
Paso. The experiment hardware is machined out of plexiglass. 
Engineers Vernon Strickland and Mike Izquierdo assisted students 
with design plans. The containers were built to specifications 
by Whaller Specialties and Falco Machine & Tool Company, The 
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power supply for the payload consists of Gates lead-acid 
batteries with a power life of 4 5  hours at 1 amp/l2 volts DC. 
The power supply will be used to operate linear actuators, light 
emitting diodes, thin film heaters and other electronic devices 
in the payload. The cost of the batteries was underwritten by El 
Paso Electric Company. 
This particular GAS payload is unique in regard to the 
planned operational scenario. Experiment 7-P( the Fuel Wicking 
Experiment) is designed to measure the wicking of a simulated 
fuel on a thin wire screen during acceleration. Its operational 
period is from SSME ignition through the OMS-1 burn. Experiment 
7-P wi 11 have a self -con,tained power supply and controller 
separate from the main payload controller and power supply. It 
will be activated by the noise of the shuttle liftoff and, 
through a timer, shut itself down upon completion of the OMS-1 
burn. 
The container w i l l  be purged with dry nitrogen prior to 
installation in the Orbiter. An insulated cover will be 
instal led over the container experiment mounting plate exterior. 
No unique flight design requirements are requested for orbit 
altitude, inclination, or orientation and stabilization. The 
assignment of GAS Control Decoder (GCD) relay states to specific 
payload functions is shows in Table 3.2.2-1. The required 
payload crew activities during the flight are shown in Table 
3.2.2-2. 
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Modular and standardized GAS payload hardware

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