Environmental Engineering Reference
In-Depth Information
where
P
SA
..
is.the.solar.panel.power.during.daylight.period.
P
e
.. is.the.power.requirement.during.eclipse,.5.kW
e
.
P
d
.. is.the.power.requirement.during.daylight,.5
kW
e
.
T
e
.. is.the.period.of.eclipse,.20.min.
T
d
.. is.the.period.of.daylight,.20.min.
X
e
.. is.the.power.transfer.eficiency.during.eclipse,.0.65.
X
d
.. is.the.power.transfer.eficiency.during.daylight,.0.85.
So,.the.solar.cell.mass.is
14
0 16
.
932 kW
14 9
.
32kW
e
0
.853 kg
/
2
P
P
×
m
SA
e
=
=
.
×
I
2
R
R
R
o
0 16
.
e
×
×
I
2
e
0
.
853 kg
/
m
2
2
14 9
.
32 kW
×
0 8
.
5
3 kg
/
m
e
=
2
(
1
AU
R
)
2
0 16
.
×
×
(
1
353 w
/
m
)
2
R
2
=
58 83
.
7 kg
.
The.battery.mass.is
1 kg
150W - hr
×
0
.5 hr 5 kW
×
=
50
.
51 kg
e
(
)
×
33
%
.
The.total.mass.is
R
2
+
58.837 kg
50.51 kg
.
This.is.shown.in.Figure 5.2..The.speciic.mass.of.the.general.purpose.heat.
source. (GPHS). is. as. follows,. where. it. is. assumed. that. the. electricity. is. 250.
watts.and.the.mass.is.54.0.kg..Each.GPHS.RTG.has.a.mass.of.about.57.kg.and.
generates.about.300.watts.of.electrical.power.at.the.start.of.a.mission.(from.
about. 4,400. watts. of. thermal. energy). from. about. 7.8. kg. of. plutonium-238.
(
238
Pu)-based.fuel.(Bennett.2006):
P
S
5 kW
250 watt 54.0 kg
GPHS
e
m
=
=
GPHS
RTG
.
=
1080.0 kg
Search WWH ::
Custom Search