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#60
by
Jim
on 08 Apr, 2011 12:22
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#61
by
robertross
on 08 Apr, 2011 15:28
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#62
by
Jim
on 08 Apr, 2011 21:12
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Heading to the SLF shortly.
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#63
by
TheFallen
on 09 Apr, 2011 01:52
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#64
by
Patchouli
on 09 Apr, 2011 04:04
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I'm surprised it doesn't have an ion engine since it will be over powered until it crosses the asteriod belt.
18kw at 1 au but only 400w at Jupiter.
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#65
by
Jim
on 09 Apr, 2011 05:33
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I'm surprised it doesn't have an ion engine since it will be over powered until it crosses the asteriod belt.
18kw at 1 au but only 400w at Jupiter.
How would it brake into orbit with the extra energy?
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#66
by
pummuf
on 09 Apr, 2011 06:02
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I'm surprised it doesn't have an ion engine since it will be over powered until it crosses the asteriod belt.
18kw at 1 au but only 400w at Jupiter.
How would it brake into orbit with the extra energy?
To reduce the trip duration and with the same braking impulse, the ion drive would spend part of the trip accelerating then part of the trip decelerating ... not that I'm saying the added complexity is worth it.
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#67
by
joek
on 09 Apr, 2011 07:20
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Thanks for the update. Serious business there and it warms my old heart to see her in capable hands. Jupiter is not to be trifled with and every bit of TLC for those destined for that inferno is appreciated. (Was part of Pioneer F/G encounter team and jeebuz those were some hairy times. We had a heckuva time maintaining control and IIRC even Van Allen was shocked at how nasty it was.)
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#68
by
Jim
on 09 Apr, 2011 13:05
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To reduce the trip duration and with the same braking impulse, the ion drive would spend part of the trip accelerating then part of the trip decelerating ... not that I'm saying the added complexity is worth it.
My point was with 18kw at 1 au but only 400w at Jupiter, how much of the trip would be spent actually accelerating?
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#69
by
Ronsmytheiii
on 13 Apr, 2011 03:58
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#70
by
Patchouli
on 13 Apr, 2011 04:04
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I'm surprised it doesn't have an ion engine since it will be over powered until it crosses the asteriod belt.
18kw at 1 au but only 400w at Jupiter.
How would it brake into orbit with the extra energy?
To reduce the trip duration and with the same braking impulse, the ion drive would spend part of the trip accelerating then part of the trip decelerating ... not that I'm saying the added complexity is worth it.
I gave it some thought an ion drive may not be worth it after all.
There won't be enough power once it crosses the asteriod belt and aerobraking is completely out of the question the radiation belts would fry it.
All braking has to be conventional rockets.
Though a mag tether could work in theory but that would be adding to much complexity.
Maybe for the next one some unconventional ideals could be tried out.
Juno is a solar powered vehicle at Jupiter that's already pretty unconventional as it is.
I wonder if it might inspire the nuclear adverse ESA to attempt a Jupiter mission.
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#71
by
GClark
on 13 Apr, 2011 04:28
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Today's reading assignment:
ESA's LaPlace Jupiter Ganymede Orbiter mission in the competition for Cosmic Vision L-1.
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#72
by
Patchouli
on 13 Apr, 2011 05:39
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Today's reading assignment:
ESA's LaPlace Jupiter Ganymede Orbiter mission in the competition for Cosmic Vision L-1.
I did a search nothing concrete yet it's supposed to be a dual mission and they may or may not have a lander.
Even considering launching every thing on some future HLV.
Ares now SLS was listed as a potential LV along with the Delta IV-H.
The out come of Juno may effect the ESA side as one vehicle was shown solar powered but I don't see how solar cells could survive the radiation environment at Europa.
Juno deals with the problem by staying clear of said belts.
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#73
by
Zed_Noir
on 13 Apr, 2011 14:39
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The out come of Juno may effect the ESA side as one vehicle was shown solar powered but I don't see how solar cells could survive the radiation environment at Europa.
If ESA mounts a Europa mission. Wonder where they would get the RTG from? Since there is a very limited supply of Pu238.
Edited for formatting
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#74
by
dsmillman
on 13 Apr, 2011 15:57
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The out come of Juno may effect the ESA side as one vehicle was shown solar powered but I don't see how solar cells could survive the radiation environment at Europa.
If ESA mounts a Europa mission. Wonder where they would get the RTG from? Since there is a very limited supply of Pu238.
Juno's orbit is a highly eccentric ellipse. So Juno spends very little time in Jupiter's radiation belt. The orbit's inclination has been selected to minimize radiation exporsure.
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#75
by
jacqmans
on 14 Apr, 2011 15:45
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Spacecraft: Juno
Launch Vehicle: Atlas V 551
Launch Site: Cape Canaveral Air Force Station, Fla.
Launch Pad: Complex 41
Launch Date: Aug. 5, 2011
Launch Time: 11:40 a.m. EDT
The Juno spacecraft arrived at Kennedy Space Center's Shuttle Landing
Facility aboard an Air Force C-17 cargo plane at 7:55 p.m. on April
8.
The spacecraft had been shipped from Lockheed Martin Space Systems in
Denver. It was offloaded from the aircraft and taken to the Astrotech
payload processing facility located near Kennedy Space Center. On
April 9, it was moved inside the processing high bay, the lid to the
shipping container was lifted from over the spacecraft, and the
protective wrap surrounding it was removed.
On April 11, Juno was lifted onto a rotation and test fixture and
rotated from the vertical to horizontal configuration so that
electrical testing could begin. Initial testing now is under way.
Antenna installations, including the high gain antenna, begin April
20.
The solar-powered Juno spacecraft will orbit Jupiter's poles 33 times
to find out more about the gas giant's origins, structure, atmosphere
and magnetosphere.
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#76
by
jacqmans
on 22 Apr, 2011 21:00
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Spacecraft: Juno
Launch Vehicle: Atlas V 551
Launch Site: Cape Canaveral Air Force Station, Fla.
Launch Pad: Complex 41
Launch Date: Aug. 5, 2011
Launch Time: 11:40 a.m. EDT
Testing of the science instruments is under way. Antenna
installations, including the high gain antenna, began April 20.
Communications system end-to-end testing with the Deep Space Network
and its associated tracking stations is scheduled to begin late next
week.
The Atlas and Centaur stages of the Atlas V rocket are scheduled to
arrive at Cape Canaveral Air Force Station the second week of May.
The solar-powered Juno spacecraft will orbit Jupiter's poles 33 times
to find out more about the gas giant's origins, structure, atmosphere
and magnetosphere.
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#77
by
TheFallen
on 05 May, 2011 01:35
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#78
by
jacqmans
on 05 May, 2011 19:39
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Spacecraft: Juno
Launch Vehicle: Atlas V 551
Launch Site: Cape Canaveral Air Force Station, Fla.
Launch Pad: Space Launch Complex 41
Launch Date: Aug. 5, 2011
Launch Time: 11:40 a.m. EDT
The Plasma Waves Instrument (WAVES) has been installed, and a
deployment test successfully was conducted on May 1. Communications
system end-to-end testing with the Deep Space Network and its
associated tracking stations was completed this week. The work to
install the three solar arrays and the associated magnetometer boom
will begin on May 18.
The solar-powered Juno spacecraft will orbit Jupiter's poles 33 times
to find out more about the gas giant's origins, structure, atmosphere
and magnetosphere.
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#79
by
Comga
on 05 May, 2011 23:05
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I'm surprised it doesn't have an ion engine since it will be over powered until it crosses the asteriod belt.
18kw at 1 au but only 400w at Jupiter.
How would it brake into orbit with the extra energy?
I don't think it works that way. Acceleration would reduce the approach velocity, as outer planets tend to sort of overrun approaching spacecraft . There are mission studies where advanced RTG powered ion engine missions get to the outer gas giants with minimal approach velocity and go into orbit. Jupiter is the target in Figure 6 of
http://sgc.engin.umich.edu/erps/IEPC_1991/IEPC1991-035.pdf However, the other answer, that there is insufficient electric power, particularly beyond the orbit of Mars, dominates the reason to not consider it.