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48 iao
4.b 11
8.2 19.3
26.5 88.6
C l e 1
76 178
51 iao
11 50
190
17
29.6
100
c1
270
100
75
--.- .-_ 7-
1) 400 ~ fn initial circular omti 2) 600 KQI opa.:ecraft
3) thwot lL.** la: ion- 40 Rw:
SPT- 60 mP(:
arcjote- 150 nM:
4) 1ogr2QO a: 5) 188-2806 cut ,
6) XQBp 1500 S; 7) Isp~500
0: ,
Tablo 3.4- 1 kloctr ic Yropulolon-oyst@mo
for OrbIt Raising
---.------- -I, .-I -.-
roble 3.4-A ShWS that IOU powor arcjots
OPO goad candidates for Rlcgh altiruae
d! eeoroneioio, provi~ing 9~ ROW OSV~~JO
with aoanonable, tranofor ticno. On tho
conerany. ion Phruetorrs , and !;mu arc?
Dorqjiml and can bo only conaidered tor
aooAl oleleudo Lncromenro, oehoarvieo too
10- eranror t1r;tao will nonult. In
concluoion. IOW Phruet olectnic propuleIon
can $3 ccnoidarod for circular orblt
rnioirrogl of amell metolllt~o whan (P short
tranetor ti- Ia not mandatory. I
Whoer oabie ralolrrcg must b@ laplononeed in
a vouy mort tiao, as for ~~o~-ple with
aotollitao launched on-demnd, 'thon
chaoiccal propulmion 1s still tho preferred
approach.
Circular toalliptical orbit tranefero
tlliptic~l Inclined orbits nro being
conr~ldord with increasing interoat for
numrwo applications, and thoro arQ plans
to roalino omall satellite conatelletionn
olrpploiting tho gsrtIcular foaturm of such
orbito. However, the injection capability
of anal1 launchera in elliptical, hlgh
onorgy, orbits is ncrmally rather pQor,
and one has , again, to rely on boost
mtora to Inploaent the final vrblt
tranofor, for which two inportant
considerations apply.
h .(
@ -'
ti"k00, V€#q high d@l~-VOlWitiQU are
mp i wx-1, mm Pig. 3.5-1. SOCORB,
C@L29311Q 1 Q 1 comuwication ustolliten
iRj&cd tn olligtical orbltm can ba
t33~1n~Od ah AeulrPchod mlZ in advanco of
ma0 ~c$dGitO. Pn>q tnip times aro, thua,
wlotbbdly uninpogtant but 8i8SiOn
cacplorziity, cooto, reilabil lty and
opaationol conoidorationm may put an
upwr RmuM to the maxiBus accaptablo trip
eim.
Eloceric Propulsion alternatives to
chooicol arb SBTa and arcjets, with the
oow chartceoriueics given in Table 1.4-1.
!3i~plbfid conputatlono POP transfers of a
500 Kg opdscocralt. in trsnsfer orbit from
an initial 400 tta circular orbit to three
Qootinetbon alliiptical orbits of 8, 12
and 24 hour6 priodn were porformod.
c~oae-idecai trenoeor vas uimulated by
firing ~RICUS~OPO eor a/4 oP the orbit
p~pho61 awue eh@ prigses until the final
opqoo wan reached, ehen firing the
Phpuotora Sou 1/6 of tho orbit period
until tho final prigoe WQD also reached.
aropollant Q~OB required by SFTs and
arcjots are roported in Table 3.5-1.
- DOltQ'V.
- T.O.neoe/
** Id001 Tranfor:
Dastination Orbit (1)
a) b) Ci
(WO) : 2350 1550 3450
peopolA.maoe
(W) (1) 1
cPIoaical 1157/657 1:'; !,'*I43 1714/3214
arcjet 800/300 R '/3J2 996/496
SPT 379/78 '. '06 620/120
- T.O. DBBD/
propoll.taaes
44 !ion-Idoel Tranmfer, A rc '*t:
(K9) (3) :
- Trip ti-
058/358 B93/399 l105/605
(days) 36) 334 530
-
Characteristics of Destination Orbits:
a) Apaqoo:32430 EOsr Perigoo:8107 Km;
Porlod: 81 hours:
b) Apocaoe:45150 #m: Perigee:7968 Km:
Poriod:li! hourQ:
c) Apoqoo:59030 KIP: Perigee: 25298 Km:
Period: 24 hours:
Moto 1) Starting orbit: civ Inr, 400 Km:
2) Satellite drymass: I O Kq
3) Inzluding Delta-V 1i':rement (15%)
for non ideal transfer
-
Tablo 3.S-1 E.P. alternativrs to chemical
peopuleion for circular to
elliptical orbits tranfers
POP ths arcjet cane, a non-ideal transfer
wan ala0 oimuletod, and tho propellant
mu@ recomputed taking into account a 15 8
worsening in tho delta-voloclty required
duo to the non-idoal tranfpr conditions.
A@ can Bo moon the trip tlrms are quits
high in all caaoo: a 30 8 rclucticn can be
achlsved incromsinq the arclnt thrust to
220 L", which would nevertheless imply the
availability of 1.8 Kw @C power. This
sight necceeitete an auxiliary array in
the E.P. boost section, impacting costs.