New Frontiers 4: Argo? |
New Frontiers 4: Argo? |
Aug 21 2008, 01:36 AM
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#1
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Member Group: Members Posts: 723 Joined: 13-June 04 Member No.: 82 |
There does not appear to be a thread about this proposed New Frontiers mission, so I am starting this one. If there is an existing thread that I am unaware of, then by all means merge them.
Argo is a proposed outer solar system multiple flyby mission, rather like an updated Voyager mission, but based on the New Horizons bus, and using a similar instrument suite. It would launch between 2017 and 2019, with either a Jupiter / Neptune / KBO or a Trojan / Saturn / Neptune / KBO trajectory. Even a combined Jupiter / Saturn / Neptune / KBO trajectory is possible. Neptune would present a much different system than in 1989, as telescopic observations show a more dynamic Neptune atmosphere, due to the change in season, and much more of Triton and the other Neptune satellites would be visible (most of Triton's northern hemisphere was in darkness in 1989, but will be well lit in 2030). The second big payoff would be the vastly greater access to KBOs (~4000 times the accessable volume of New Horizons), with several already-known large KBOs (400km diameter or larger) within reach. The objects reachable with Argo are expected to include: 18 cold classical KBOs (interesting because they apparently formed in situ beyond Neptune's orbit, rather than further inward) 40 KBOs with diameters between 200km and 400km 9 KBOs with diameters greater than 400km several binary KBOs plus the possible Jupiter Trojan early in the mission. The wide expected range of choices allows for the selected KBO to be of very high scientific interest (and naturally, follow-on KBO targets could be selected after the primary KBO target has been selected). Typical flight times from launch to the Neptune flyby are about 10 years (Jupiter gravity assist) or 13 years (Jupiter Trojan flyby), with the large KBO flyby 2 or 3 years later. Expected cost including launch vehicle (according to the linked pdf): under $800M with the following strawman instrument package: High resolution visible camera: New Horizons (NH) or reduced Cassini heritage Near-IR spectrometer: NH heritage UV solar & stellar occ. spectrometer: reduced Cassini heritage Far-IR linear radiometer: Diviner heritage Magnetometer: replaces NH dust instrument Charged particle spectrometer: NH heritage Gimballed high-gain antenna: heritage radio science instrument The big uncertainty at this point seems to be the availability of plutonium-powered RTGs by the time of launch. |
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Aug 22 2008, 01:34 AM
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#2
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Member Group: Members Posts: 723 Joined: 13-June 04 Member No.: 82 |
It is interesting that from what I read here at Unmanned Spaceflight, NASA is leaning toward a Jupiter orbiter for the third New Frontiers mission, with the candidates from the existing list being Io Observer and Ganymede Observer (I would prefer Io, myself). That would (if Argo is also chosen) result in the first four New Frontiers starts being 'outer solar system' missions (where the outer solar system begins at Jupiter's orbit) and the 11 Discovery starts being 'inner solar system' missions.
New Frontiers 1 : New Horizons --> Jupiter flyby / dwarf planet (Pluto) flyby / small KBO flyby -- launched 2006 New Frontiers 2 : Juno --> Jupiter polar orbiter (focus on Jovian gravity & magnetic fields) -- launch 2011 New Frontiers 3 : Io Observer --> Jupiter orbiter (focus on Io) -- launch 2013 New Frontiers 4 : Argo --> Jupiter Trojan flyby / Saturn flyby / Neptune flyby / dwarf planet flyby -- launch 2017-19 To fly all of these NASA would have to use the Advanced Stirling Radioisotope Generator (ASRG), which it seems they would like to do (at least for Discovery-class missions). It makes sense that the slightly larger budget per mission New Frontiers program be focused on the more expensive to explore outer solar system, although I would not be upset if New Frontiers 3 ends up being the Venus In Situ Explorer, which is another favourite of mine. |
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Aug 22 2008, 03:40 AM
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#3
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Member Group: Members Posts: 715 Joined: 22-April 05 Member No.: 351 |
That would (if Argo is also chosen) result in the first four New Frontiers starts being 'outer solar system' missions (where the outer solar system begins at Jupiter's orbit) and the 11 Discovery starts being 'inner solar system' missions. The next New Frontiers (#3) will be solar powered because the the tight plutonium supply. I think that makes a Jovian system mission unlikely, although it is probably technically feasible for the Ganymede observer and possibly an Io observer, although the interaction of radiation and solar cells is a big risk. My guess is that the next New Frontiers (3) will be a comet or a Venus mission and New Frontiers 4 will be an outer planet mission with Argo in competition with a mission to whichever system (Jovian or Saturnian) does get the choice for the Flagship mission. It's possible that Stirling plutonium Discovery mission could go to the Jovian system, but Juno barely fits in the New Frontiers cost cap. I have doubts that any Discovery mission could, even with a free power source. -------------------- |
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