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Old 09-03-2012, 07:26 AM   #1
Unstung
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Default Why not another Curiosity?

I imagine that R&D is the bulk of a spacecraft's cost. If it is, why doesn't NASA create duplicates of spacecraft more often? The agency has obviously done this a few times, such as Viking, Voyager, and the MERs. There were four finalist landing sites that Curiosity could have visited, and another rover could have visited the second-best.

My question also applies to sending similar spacecraft to different planetary targets. Cassini obviously has instruments that make it adept to study the Saturn system, but why not make a spacecraft very much like Cassini and send it to a barely explored ice giant. Obviously Cassini uses Titan to change its orbit, but a duplicate Cassini that studies Uranus or Neptune could be much cheaper to produce.
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Old 09-03-2012, 07:31 AM   #2
VincentMcConnell
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Because Curiosity was fake *bum bum bum*!
That's why we haven't gone back.

No, just kidding. I think -- like you mentioned with cost -- it is really all about money and effort. A real space mission is a huge thing that takes a lot of planning and money -- even if only a duplicate of the previous mission. Unfortunately we can't just take off like Kerbal or Orbiter and come back and do it all over again. It would be nice to see some more Curiosity Rovers in the not-too-distant future, though.
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Old 09-03-2012, 07:52 AM   #3
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Because there are also other costs as well, for example mission control and spacecraft tracking, which isn't for free as well.
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Old 09-03-2012, 10:34 AM   #4
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I doubt that just cloning a space craft and sending it somewhere else would work well. It's probably best to adopt the systems for their particular environments.

An obstacle in reaching Uranus and Neptune with an orbiter is first the huge amount of delta-v required to get there, the rare launch windows and the difficulty in establishing an orbit.

As for a duplicate Curiosity, you have to value the cost and rewards. What would a duplicate learn that the primary couldn't?

I suspect that duplicates were also used in the past for extra security - if one of the launches failed, for example.
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Old 09-03-2012, 11:49 AM   #5
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Those science spacecrafts are prototypes. They are not meant for mass production, everything is tailored for that specific mission.
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Old 09-03-2012, 04:05 PM   #6
T.Neo
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There probably isn't much harm in reusing a general design or spacecraft bus for several scenarios, if specific hardware is swapped out or updated as is appropriate.

Using systems on various spacecraft isn't unheard of. New Horizons uses a surplus Cassini RTG, for example.
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Old 09-03-2012, 04:06 PM   #7
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It depends on many things. They send a duplicate for the previous rover missions (spirit and opportunity) but one factor that may (and I mean 'may', I'm just guessing here) is the power source. Curiosity is powered by Plutonium for its RTG and that's very-much in short supply nowadays as it was a byproduct of old nuclear bomb manufacturing. I read a while ago that the USA has a small stockpile of it, but it's about to runout and after that it'll have to buy it from Russia.
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Old 09-03-2012, 04:26 PM   #8
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Quote:
Originally Posted by T.Neo View Post
 There probably isn't much harm in reusing a general design or spacecraft bus for several scenarios, if specific hardware is swapped out or updated as is appropriate.
Has been done by ESA... Mars Express, Venus Express (who remembers it?) and Rosetta share the same satellite bus.
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Old 09-03-2012, 04:39 PM   #9
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Curiosity was already a daring shot because the landing mode was a bold new approach and nobody knew if they were about to make a brand new crater on Mars. Making more of a design that wasn't guaranteed to even make it to the surface in one piece would have been a crazy bet.

Making more Spirits and Opportunities would have made more sense.
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Old 09-04-2012, 02:36 AM   #10
Unstung
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How much could NASA save if it sent a spacecraft based heavily on Galileo to Saturn rather than Cassini? I don't know how similar the two spacecraft are, but they look very different. Galileo itself was cheaper.


Quote:
Originally Posted by Urwumpe View Post
 Has been done by ESA... Mars Express, Venus Express (who remembers it?) and Rosetta share the same satellite bus.
Also, the upcoming InSight mission is a copy of Phoenix's design. Despite being similar, I have found that Phoenix was cheaper, not adjusting for inflation. But both are relatively low-cost missions.


Quote:
Originally Posted by agentgonzo View Post
 It depends on many things. They send a duplicate for the previous rover missions (spirit and opportunity) but one factor that may (and I mean 'may', I'm just guessing here) is the power source. Curiosity is powered by Plutonium for its RTG and that's very-much in short supply nowadays as it was a byproduct of old nuclear bomb manufacturing. I read a while ago that the USA has a small stockpile of it, but it's about to runout and after that it'll have to buy it from Russia.
http://www.npr.org/2011/11/08/141931...for-space-fuel

Last edited by Unstung; 09-04-2012 at 02:40 AM.
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