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#20
by
deadman1204
on 18 Jan, 2022 21:29
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Yeah, one of the killers for ESA-led missions to the ice giants (and makes Saturn difficult too) is a lack of RTGs;
Would it be feasible to have NASA contribute the RTG on an ESA-led mission?
I'm thinking of JWST, where ESA contributed one of the instruments and the launch to a NASA-led mission.
Or would you run into ITAR or nuclear-related legal issues exporting an RTG?
This would never happen. The US doesn't have enough plutonium and has to be very stingy about what missions get an RTG. They would never give a full RTG to ESA.
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#21
by
AS_501
on 18 Jan, 2022 21:57
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I'm puzzled by the choice of words in the Moons of the giant planets theme
"Investigating the habitability potential of worlds in our Solar System is essential for understanding the emergence of life..."
To me the term "habitability" suggests astronaut encampments in the far future. Jupiter's Galilean moons are bathed in heavy radiation from the planet, even as far out as Callisto. Maybe I'm misinterpreting this.
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#22
by
Blackstar
on 19 Jan, 2022 00:51
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To me the term "habitability" suggests astronaut encampments in the far future. Jupiter's Galilean moons are bathed in heavy radiation from the planet, even as far out as Callisto. Maybe I'm misinterpreting this.
You are misinterpreting it. The scientific definition of habitability means its ability to support life, not astronauts. So amoebas are fine, shrimp are great, and fish are bleeping wonderful.
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#23
by
Alpha_Centauri
on 19 Jan, 2022 07:11
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Of course water is a pretty decent shield against most radiation. If you could get below the ice into the ocean on Europa an aquatic artificial habitat would be fairly well protected.
But yes, habitability in this context means for potential extraterrestrial life.
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#24
by
Don2
on 03 Feb, 2022 09:11
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If there was a lead time of more than 10 years, then I don't see why the US couldn't supply an RTG to ESA. Investments could be made to increase Pu-238 production by debottlenecking the current production process, which would also tend to decrease the unit cost.
One of the missions being studied for the decadal is an astrobiology mission to Enceladus. If the Europeans wanted to go to Enceladus, then NASA might supply an RTG if the Europeans agreed to host an American instrument on their mission. The Europeans could also make a generous contribution to a US lead Ice Giant mission, which they might be happy to do because some European scientists are interested in Ice Giants.
There is another aspect to this. I think that a lot of the science from the atmosphere probe on an Ice Giant mission will come from comparing the results to Jupiter. Having atmosphere probe data from Saturn as well would probably be very valuable when modeling solar system formation scenarios. Perhaps the Europeans could supply two probes, one for their own Saturn mission and one for a US Ice Giants mission. They could also host a US astrobiology instrument on their Saturn mission and in return would get a US RTG to power it.
However, it is possible that solar panel technology has advanced to the point where RTGs are not really needed for Saturn. The Voyage 2050 report states on page 10 :
Technology developments on higher efficiency solar cells have been ongoing at ESA making a solar-powered mission in the Saturnian system not only feasible but also operationally flexible and capable of hosting advanced instrumentation.
The Europeans are clearly very interested in the Ice Giants. On page 28 they say:
A mission towards Uranus and/or Neptune is a necessary step in the exploration of the Solar System, filling the current, huge, knowledge gap,...
... A partnership with another agency is an absolute necessity. One possibility would be a Medium class contribution in a mission led by an international partner. It could for instance consist of an atmospheric entry probe, a Triton lander, or some key instrumentation....
...it is strongly recommended that every effort is made to pursue this theme in order to set up a cooperation scheme on a future mission to the Ice Giants.
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#25
by
Alpha_Centauri
on 03 Feb, 2022 14:10
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Thanks to the mess of Nasa pulling out of Exomars, L-class missions must now be explicitly ESA-led, so there will be an ESA-led Jupiter/Saturn moons mission regardless of what Nasa does. ESA could also join a separate Nasa-led moons mission with an M-class, though it would be in competition with lots of other priorities.
Yes as you note, ESA now considers solar array technology mature enough for capable large Jupiter and Saturn missions. That's why conspicuously the 'giant planet' moons mission focuses on those to the exclusion of the ice giants, it's just implicitly assuming sufficient RTG technology won't be available.
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#26
by
Blackstar
on 03 Feb, 2022 14:48
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If there was a lead time of more than 10 years, then I don't see why the US couldn't supply an RTG to ESA. Investments could be made to increase Pu-238 production by debottlenecking the current production process, which would also tend to decrease the unit cost.
Note that doing so would require some kind of joint mission. In other words, in return for the US supplying the RTG, the US also gets to supply instruments and have participation on the science team. Yes, this is possible. But all of this requires coordination. (I don't see the US ever "trading" an RTG for something not related to the mission that it is on. In other words, we would not give ESA an RTG in return for a launch on an Ariane 5.)
There is a possibility of increasing US Pu-238 production, but that's not the only thing that has to be increased. There are other limits along the supply chain, particularly how many fuel clads can be produced per year. Just increasing Pu-238 supply would mean that it would pile up, like pumping a lot of oil out of the ground but not having capacity at the refinery to process it.
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#27
by
Don2
on 04 Feb, 2022 10:08
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Depending on when this European mission flies, it might not be necessary to expand Pu-238 and RTG production. I noticed that the LISA mission won't fly until 2037, so perhaps the Jupiter/Saturn moons mission won't fly until the early 2040s.
I think there are two great opportunities in the outer solar system. Both astrobiology at Enceladus and an Ice Giant mission will be prestigious, high profile missions. I think that ESA should jump on whichever one the Decadal does not pick as #1 and try to make it happen even if it requires making a deal with the US for an RTG.
The US will eventually do both so if the Europeans want to be first they will need to launch by the mid-2030s.
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#28
by
deadman1204
on 04 Feb, 2022 16:44
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If there was a lead time of more than 10 years, then I don't see why the US couldn't supply an RTG to ESA. Investments could be made to increase Pu-238 production by debottlenecking the current production process, which would also tend to decrease the unit cost.
The US is very limited in how much Pu-238 it can produce. Lead time is irrelevant when there isn't enough as is. Increasing the production rate is a multi billion dollar decade long proposition. We are incredibly risk adverse to anything with the word nuclear in it.
If there is a joint NASA-ESA mission, an RTG could be possible, but there is no near future scenario where NASA sells/gives away an RTG.
Consider the Juno orbiter and Lucy. Going out of our way to try and do solar 5 AU out and all that work BECAUSE there isn't enough plutonium to go around.
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#29
by
Blackstar
on 04 Feb, 2022 17:29
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Increasing the production rate is a multi billion dollar decade long proposition.
It's not "multi billion dollars" to increase Pu-238 production. The numbers are not public, but the planetary decadal survey asked about it. There's a path to increasing production, but cost depends upon how much and there's a step function where you have to build new equipment and so on--for instance, increasing production by 25% might not cost that much, but 50% would cost a lot more.
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#30
by
MRJC
on 23 Sep, 2022 16:40
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#31
by
skizzo
on 26 Mar, 2024 14:57
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#32
by
skizzo
on 26 Mar, 2024 15:06
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#33
by
LouScheffer
on 28 Mar, 2024 15:53
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The report:
https://cosmos.esa.int/documents/1866264/1866292/ESA_L4_Expert_Committee_report_Voyage_2050_Moons_of_the_Giant_Planets.pdf
These quotes still seem counterproductive to me: "the L4 mission concepts considered in this study, with launch in the early 2040s" and "During the CDF studies, the scenario considered was a single A64 launcher. Only after the conclusion of the CDF studies was a double launch scenario introduced for the Enceladus mission, (see paragraph below)."
I realize this is a national prestige matter, but I'd think the prestige attaches to the science, not the launcher. And talking *18 years* in advance, surely some advance in launcher technology can be assumed. And at some point, launch will become a commodity. Perhaps an analogy is research at the South Pole - no one cares what ship brought the equipment, just what the research reveals.
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#34
by
ccdengr
on 28 Mar, 2024 16:14
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Perhaps an analogy is research at the South Pole - no one cares what ship brought the equipment, just what the research reveals.
I'm not sure that's a great example, considering that the vast majority (all?) of NSF flights to the South Pole are done with US military aircraft. "More and Better Science in Antarctica through Increased Logistical Effectiveness"
https://www.nsf.gov/geo/opp/usap_special_review/usap_brp/rpt/antarctica_07232012.pdf
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#35
by
Blackstar
on 28 Mar, 2024 20:56
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I realize this is a national prestige matter, but I'd think the prestige attaches to the science, not the launcher. And talking *18 years* in advance, surely some advance in launcher technology can be assumed. And at some point, launch will become a commodity. Perhaps an analogy is research at the South Pole - no one cares what ship brought the equipment, just what the research reveals.
In other words, you want to discuss Starship in this thread.
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#36
by
Eric Hedman
on 28 Mar, 2024 21:39
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I realize this is a national prestige matter, but I'd think the prestige attaches to the science, not the launcher. And talking *18 years* in advance, surely some advance in launcher technology can be assumed. And at some point, launch will become a commodity. Perhaps an analogy is research at the South Pole - no one cares what ship brought the equipment, just what the research reveals.
In other words, you want to discuss Starship in this thread.
I didn't think there were any Starship free threads on this site once a thread passes 20 comments. But it does bring up a point. How do you realistically start planning for missions fifteen to twenty years out knowing that there is potential for massive technology advancements in a number of areas that could significantly change the mission architecture for the the better?
I had this discussion with my congressman at the time Jim Sensenbrenner (former chair of the House Science Committee). We were discussing the ITER nuclear fusion project. He thought, and I agreed, that committing to a design thirty years to complete was completely ridiculous and a big waste of money because it ignores potential breakthroughs along the way. I think it is reasonable to come up with general goals for twenty years out, but not specific designs to accomplish them.
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#37
by
MickQ
on 29 Mar, 2024 00:37
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I realize this is a national prestige matter, but I'd think the prestige attaches to the science, not the launcher. And talking *18 years* in advance, surely some advance in launcher technology can be assumed. And at some point, launch will become a commodity. Perhaps an analogy is research at the South Pole - no one cares what ship brought the equipment, just what the research reveals.
In other words, you want to discuss Starship in this thread.
More likely to be Ariane Next, isn’t it ??
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#38
by
matthewkantar
on 29 Mar, 2024 01:03
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I think it’s best to design for what exists. Europa Clipper was going to launch on SLS, a cheaper gentler ride came along, it’s going to go on FH. No need to clog up all the threads with future launchers.
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#39
by
Hobbes-22
on 29 Mar, 2024 07:10
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I had this discussion with my congressman at the time Jim Sensenbrenner (former chair of the House Science Committee). We were discussing the ITER nuclear fusion project. He thought, and I agreed, that committing to a design thirty years to complete was completely ridiculous and a big waste of money because it ignores potential breakthroughs along the way. I think it is reasonable to come up with general goals for twenty years out, but not specific designs to accomplish them.
We're at a point where projects as complicated as ITER take 20 years to build. The start of that build is when you should freeze the design, otherwise you'll be restarting construction and adding years to the build over and over again.
Before that, there's going to be years of designing, and before that, there's going to be years of R&D before you can settle on a design. We could speed that up by increasing funding, but as we've seen with ITER, that's not happening. So we end up with having to freeze the design 30 years before the reactor becomes operational.