The space shuttle orbit prediction program uses the Jacchia Atmospheric model. The errors in the shuttle orbit prediction are investigated by not considering variations in solar flux or geomagnetic activity

Solis, A. J.

English

NASA Technical Reports Server

PROPOSED CHANGES IN THE 
MISSION CONTROL JACCHIA ATMOSPHERIC MODEL 
Job Order 81 -1 67 
(NASA-CS- 451 357) PROPOSBD CEABGBS I N  THB 377-23137 
HISSIO# CONTROL J1CCHIA ATBOSPREPIC BODEL 
(Lockheed Electronics Co.) 7 p BC AOZ/PSF 
A0 1 CSCL 2 2 B  Unclas 
63/12 m u a  
Prepared By 
Lockheed Electronics Company, Inc. 
Systems and Services Division 
Houston, Texas 
Contract NAS 9-1 5200 
For 
MISSION vLANNING AND ANALYSIS DIVISION 
N a l i o ~ l  
'NDON 
A a m a u i i a  and Space Adlllhhtmtion 
B. JOHNSON SPACE CENTER 
Hou8tosr, T h m  
April 1977 
LEC-10447 
https://ntrs.nasa.gov/search.jsp?R=19770016193 2020-03-22T08:49:21+00:00Z
TECHNICAL MEMORANDUM 
PROPOSED CHANGES IN  THE 
MISSION CONTROL JACCHIA ATMOSPHERIC MODEL 
Job Order 81 -1 67 
PREPARED BY 
APPROVED BY 
@ 4 J U  
F. rake, Supervisor 
~ a v i  g t i o n  ~ n a l y s i  s Section 
m- 
F. N. Barnes, Manager 
Dynamic Systems Department 
Prepared By 
Lockheed E l  ec t ron i  cs Company, Inc. 
For 
Mission Planning and Analysis D iv is ion  
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
LYNDON B. JOHNSON SPACE CENTER 
HOUSTON, TEXAS 
A p r i l  1977 
TECHNl CAL REPORT IWDEX/ABSTRACT 
(See inatructron.  on reverse a r d e . )  
1 .  TITLE *NO S U ~ T I T L E  O F  DOCUMENT 
Proposed Changes i n  the Mission Control Jacchia 
Atmospheric Model 
2. JSC NO. 
JSC- 12616 
3 .  CONTRACTOR/ORGANIZAT I  ON NAME 
Lockheed Electronics Company, Inc. 
5 .  C O N T R A C T O l l O R l G l N A T O R  DOCUMENT NO. 
LEC-10447 
7.  S E C U R I T Y  C L A S S I F I C A T l O k  
Unclassif ied 
9. L I M I T A T I O N S  
GOVERNMENT H A S  UNLIMITED R I G H T S  ~ V E S  ONO 
I F  NO. S T A T E  L l M l T A T l O N S  AND A U T M O R I T V  
1 1 .  D O C U ~ E R T  COIII&CI n f f t ~ f w c f s  
*OR* BREAKDGWh STRUCTURE NO. 
der 81-167 
CONTRACT E X H I B I T  NO. 
O I L  NO. AND R E d I S I O N  
DRL  L I N E  I T E M  NO. 
1 3 .  ABSTRACT 
4. C O N T R A C T  OR G R A N T  NO. 
NAS 9-1 5200 
6 .  P U B L I C A T I O N  D A T E  I T H I S  I S S U E )  
Ap r i l  1977 
0 .  OPR ( O F F I C E  OF C R I M A Q V  R f S C O N S I B l L l T Y I  
Mission Planning and Analysis 
. . .  
10.  A U T H O R I S )  
A. J. So l is  
1 2  I i A l R A l t  COI IFIEU~A~IOI  
SYSTEM 
SUBSYSTEM 
MAJOR E O U I P M E N T  GROUP 
i 
I 
t 
i 
f 
I 
I 
i 
I 
I 
2 
5 i r 
i- 
I 
: 
E 
The Space Shutt le o r b i t  p red ic t ion  program uses the Jacchia Atmospheric model. 
This model does not consider changes i n  density due t o  var iat ions i n  the solar  
f l u x  o r  geomagnetic a c t i v i t y .  This report  invest igates the errors i n  the 
Shutt le o r b i t  predict ion by not considering var iat ions i n  solar f lux  o r  
geomagnetic ac t i v i t y .  
1 4 .  a U e I f C T  Itls 
rn 
A 
1 INTRODUCTION 
The Space Shut t le  o r b i t  p red i c t i on  program used by Mission Control uses the 
Jacchia model t o  compute the densi ty  o f  the atmosphere. Two e f f e c t s  no t  
incorporated i n  the Jacchia model (reference Jacchia) are changes i n  dens i ty  
due t o  (1) d a i l y  va r i a t i on  i n  the FlOm7 cm so lar  f l ux ,  and (2) hour ly  v ~ r i a -  
t i ons  i n  the geomagnetic index. The purpose o f  t h i s  i nves t i ga t i on  was t o  
ascertain whether o r  no t  these two e f f e c t s  should be added t o  the reference 
Jacchi a. 
METHOD 
A reference t r a j e c t o r y  was calculated using the  reference Jacchia. A compar- f 
ison t r a j e c t o r y  was generated using the same reference Jacchia p lus  a var iab le  i r 
experimental e f fec t .  The d i f fe rence between the reference and compari son t r a -  i 
j ec to r i es  suggests the e r r o r  i n  the Shut t le  o r b i t  p red i c t i on  program. This e r r o r  i ii 4 
i s  due t o  the exclusion o f  the experimental e f f e c t  from the reference Jacchia. i 
i 
The reference Jacchia atmospheric model computes the n ight t ime minimum o f  the i i 
( c) 3 global exospheric temperature T when the geomagnetic index i s  zero, from 6 1 
the equation f 
- (1 i Tc = 383' 3.32' FlOB7 
i s  the 90-day average o f  the solar  f l u x .  To consider a d a i l y  where FI0. 
var iat ion,  an addi t ional  term i s  added t o  eq. (1 ) g i v i i ~ g  
where Floe i s  the d a i l y  va r i a t i on  i n  the solar  f l ux .  A reference t r a j e c t o r y  
was generated using values o f  150, 200, and 250 f o r  F10,7. For each value o f  
? 
- 
FlOa7, two comparison t r a j e c t o r i e s  were generated, one w i t h  a d a i l y  va r i a t i on  
lower than the reference, and the other higher. Values o f  FlOa7 used were 
110, 190, 160, 240, 175, and 275. The comparison t r a j e c t o r i e s  calculated Tc 
from eq. ( 2 ) .  
The densi t y  var ia t ions  w i t h  geomagnetic a c t i v i  t j  was represented by adding t o  
the exospheric temperature a quant i ty  T which i s  a funct ion of the  geomagnetic 
9 
index. The equation f o r  T takes the form 
9 
where kp i s  the value for the geomagnetic index. The reference Jacchia uses 
the year ly  average of kp i n  eq. (3) t o  ca lcu la te  T This does no t  take i n t o  9 ' 
account any va r ia t i on  t h a t  might occur i n  kp. As i n  the  so la r  f l u x  p a r t  o f  
the invest igat ion.  the concept o f  using the downtrack e r r o r  between a reference 
t r a j e c t o r y  and a comparison t r a j e c t o r y  was used. A reference t r a j e c t o r y  was 
3 generated using eq. (3)  w i t h  a year ly  average o f  2.2 f o r  kp. Four comparison 
t ra jec to r i es  were made, using values o f  6 ,  5, 4, and 3 f o r  kp i n  eq. (3 )  t o  
simulate changes i n  the geomagnetic index. For a1 1 the geomagnetic t r a j e c t o r i e s  
generated, Tc was calculated using eq. (1) w i th  180 used f o r  F10.7. The average 
time lag  between va r ia t i on  i n  the geomagnetic index and those i n  temperature i s  
6 .7  hours. For the purpose o f  t h i s  invest igat ion,  i t  was necessary t o  assume 
t h a t  the change i n  the geomagnetic index occurred 6.7  hours before the s t a r t  of 
the mission and t h a t  i t  maintained the comparison value o f  kp f o r  the  dura t ion  
o f  the mission. 
A l l  t r a j e c t o r i e s  computed were t yp i ca l  Space Shut t le  type o r b i t s .  Table I 
notes the elements f o r  each o f  the three c i r c u l a r  o r b i t s  used. A mu l t i s tep  
Adams-Bashforth-Moulton in tegra tor  was used w i th  a fourth-order geopotent ial  
model. In tegra t ion  t ime was 7 hours, about f i v e  revolut ions.  
Results from the va r ia t i on  i n  so lar  f l ux  can be found i n  tab le  11, and tab le  
I11  shows the r e s u l t s  from the va r ia t i on  i n  the geomagnetic index. The two 
numbers separated by a hyphen i n  tables I 1  and I 1 1  are the reference value and 
the comparison value, respect ive ly .  Dashes ind ica te  no data was avai lab le.  
CONCLUSION 
A f te r  the errors were examined, i t  was concluded t h a t  the er rors  were not  
s i g n i f i c e n t  so as t o  j u s t i f y  changes i n  the Mission Control Jacchia Atmospheric 
model. 
t 
TABLE I .- ELEMENTS OF CIRCULAR ORBITS 
Orb i t a l  Elements Orb i t  1 O r b i t  2 O r b i t  3 
Semimajor axis, km 6563 6600 6841 
Inc l i na t i on ,  deg 5 7 38 57 
A l t i tude ,  km 
TABLE 11.- DOWNTRACK ERROR DUE TO VARIATIONS OF SOLAR FLUX IN KILOMETERS 
Orb i t  150-1 10 150-1 90 200-160 200-240 250-1 75 250-275 
1 4.6 4.3 3.7 - 5.6 - 
2 2.4 2.3 2.1 2.0 3.4 1 .O 
3 0.03 0.03 0.05 - 0.11 0.04 
TABLE I I I .- DOWNTRACK ERROR DUE TO VARIATIONS OF 
GEOMAGNETIC INDEX I N  KILOMETERS 
O r b i t  2.2-6.0 2.2-5.0 2.2-4.0 2.2-3.0 
1 5.4 3.9 2.5 1.1 
2 1.4 2.3 - 0.64 
3 0.09 - 0.04 0.02 
REFERENCES 
1. Jacchia, L. G . ,  New Sta t ic  Models o f  the Thermosphere and Exosphere with 
Empirical Temperature Prof i 1 es, Smi thsonia Astrophysical Observatory 
Special Report 313, May 6, 1970. 
2. Lewis, J. R , ,  Users Guide f o r  the JACHIA Program, TRW Document 
5522.7-70-38, March 10, 1970. 


Proposed Changes in the Mission Control Jacchia Atmospheric Model

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server