Author Topic: New Frontiers 4  (Read 41059 times)

Online Blackstar

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Re: New Frontiers 4
« Reply #240 on: 11/14/2017 05:30 PM »
Furthest out privately funded mission that I've heard of was to Uranus. Got to the mission planning stage. He wanted an orbiter...

A colleague who used to work at JPL looked at designing a "low cost" ice giants mission. It was going to be a magnetic field mission and I cannot remember if he targeted Uranus or Neptune. I think it was going to be flyby only, with a very minimal instrument suite. And he wanted to do it with solar, to avoid the RTG cost. He couldn't really get it to work, but the problem was in the details, not the basics. I seem to remember that he said that it would have very low power requirements and very big solar arrays, but the problem was that the spacecraft got really rickety with the big arrays and could not really do any course correction without shaking like crazy. This was not supposed to be privately funded, he was just trying to get the cost down where it might fit in a Discovery cost cap. Didn't work. Outer planets get really challenging.

Online Space Ghost 1962

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Re: New Frontiers 4
« Reply #241 on: 11/14/2017 06:22 PM »
Furthest out privately funded mission that I've heard of was to Uranus. Got to the mission planning stage. He wanted an orbiter...

A colleague who used to work at JPL looked at designing a "low cost" ice giants mission. It was going to be a magnetic field mission and I cannot remember if he targeted Uranus or Neptune.
Believe I heard of it. Don't know if they ever got my advice.

(My first deep space mission was as an intern on an early Pioneer mission to Venus that got cancelled (I'd done the software work on matching IR spectrum for a ARC planetary scientist as a prelude to an instrument, and got pulled into handling the press for Pioneer 10's encounter with Jupiter to buy them time as the images came in scan line by scan line, and the software failed to assemble them. Dancing around in N245's auditorium.)

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I think it was going to be flyby only, with a very minimal instrument suite. And he wanted to do it with solar, to avoid the RTG cost.
Like what I was referring to. (If the guy gets off his orbiter fixation, perhaps it might happen.)

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He couldn't really get it to work, but the problem was in the details, not the basics. I seem to remember that he said that it would have very low power requirements and very big solar arrays, but the problem was that the spacecraft got really rickety with the big arrays and could not really do any course correction without shaking like crazy.
Sounds like the one about 6-7 years back or so? Southern California "patron" IIRC?

Solar has changed a bit since them, and we solved the energy density problem by reusing the HGA as a solar concentrator ;) and used spin stablized platform with a single thruster, like with earlier Pioneers. Needs careful design.

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This was not supposed to be privately funded, he was just trying to get the cost down where it might fit in a Discovery cost cap. Didn't work. Outer planets get really challenging.
They are. But it's on the edge of doing. Think it wil be eventually done.

By the way, the LASPies have a great cubesat program, interesting experiences with MAVEN and EMM. Not a bad place for an deep space cubesat/smallsat program, as long as the Caltech connection could be handled somehow. There's a certain key asset there for this kind of thing.

(Some of what I experienced from McKay/others is that the "lesser" programs/projects at Caltech get unstable responses where they bump elbows with the "big budget" guys.) I've found that at UC Berkeley's SSL they don't take smallsat projects seriously, especially for interplanetary. This extends to Arizona's LPL and JHU's APL too. Touchy crowd.

Offline DarkenedOne

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Re: New Frontiers 4
« Reply #242 on: 11/14/2017 07:24 PM »
Furthest out privately funded mission that I've heard of was to Uranus. Got to the mission planning stage. He wanted an orbiter...

A colleague who used to work at JPL looked at designing a "low cost" ice giants mission. It was going to be a magnetic field mission and I cannot remember if he targeted Uranus or Neptune. I think it was going to be flyby only, with a very minimal instrument suite. And he wanted to do it with solar, to avoid the RTG cost. He couldn't really get it to work, but the problem was in the details, not the basics. I seem to remember that he said that it would have very low power requirements and very big solar arrays, but the problem was that the spacecraft got really rickety with the big arrays and could not really do any course correction without shaking like crazy. This was not supposed to be privately funded, he was just trying to get the cost down where it might fit in a Discovery cost cap. Didn't work. Outer planets get really challenging.

RTGs do not cost that much.  If you look at the budget requests for the plutonium production it comes out to millions of dollars per kilogram.   While that sounds expensive the cost of trying to do it with solar is far more if it is even possible.  The real problem with RTGs is that there is no commercial market for them.   I do not think that it is the case that it would be illegal for a commercial company to produce it.   There are plenty of commercial operations producing radioisotopes for the medical and scientific industries.  I think that historically because only NASA and the Soviet Union had a need for them no real commercial market developed.  The situation is changing though.  There are many more organizations now who are interested in operations that require RTGs.  These organizations include space agencies like ESA, CNSA, and ISRO.  There are also private companies who want to do things like land on the moon.  Ultimately someone is going to start selling this stuff.  I just hope that our regulatory bodies don't prevent that from being us.

Online Blackstar

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Re: New Frontiers 4
« Reply #243 on: 11/14/2017 07:39 PM »
Furthest out privately funded mission that I've heard of was to Uranus. Got to the mission planning stage. He wanted an orbiter...

A colleague who used to work at JPL looked at designing a "low cost" ice giants mission. It was going to be a magnetic field mission and I cannot remember if he targeted Uranus or Neptune. I think it was going to be flyby only, with a very minimal instrument suite. And he wanted to do it with solar, to avoid the RTG cost. He couldn't really get it to work, but the problem was in the details, not the basics. I seem to remember that he said that it would have very low power requirements and very big solar arrays, but the problem was that the spacecraft got really rickety with the big arrays and could not really do any course correction without shaking like crazy. This was not supposed to be privately funded, he was just trying to get the cost down where it might fit in a Discovery cost cap. Didn't work. Outer planets get really challenging.

RTGs do not cost that much.  If you look at the budget requests for the plutonium production it comes out to millions of dollars per kilogram.   While that sounds expensive the cost of trying to do it with solar is far more if it is even possible.  The real problem with RTGs is that there is no commercial market for them.   I do not think that it is the case that it would be illegal for a commercial company to produce it.   There are plenty of commercial operations producing radioisotopes for the medical and scientific industries.  I think that historically because only NASA and the Soviet Union had a need for them no real commercial market developed.  The situation is changing though.  There are many more organizations now who are interested in operations that require RTGs.  These organizations include space agencies like ESA, CNSA, and ISRO.  There are also private companies who want to do things like land on the moon.  Ultimately someone is going to start selling this stuff.  I just hope that our regulatory bodies don't prevent that from being us.

There's so much wrong with this that I wouldn't know where to start in correcting it, so I won't bother. It's just wrong.

Online Blackstar

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Re: New Frontiers 4
« Reply #244 on: 11/14/2017 08:18 PM »
For the past four years or so, NASA has been spending something like $50 million per year to restart Pu-238 production. I believe that this year, for the first time in about three decades, they made about 700 grams of Pu-238. So, if anybody is counting, that works out to about $200 million for 700 grams of Pu-238...

But, once they get up to full production, they'll be spending about $50 million for 1.5 kilograms, so the cost will be... $50 million for 1.5 kilograms. For comparison, 1.5 kilograms of gold would cost you about $65K.


Offline ArbitraryConstant

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Re: New Frontiers 4
« Reply #245 on: 11/14/2017 09:32 PM »
Mind you Thorium is omnipresent, and its most common isotope is has a long half life. You can get low energy density RTG's using a Berkeley prof's liquid crystal to extract energy.
Apologies if I'm missing something but adding up the Thorium-232 decay chain I get ~0.033 Wth/ton, which is low power density indeed. Hard to believe solar wouldn't beat that, even in the Kuiper Belt. My understanding was Americium-241 was the next best RTG material, it can be extracted from civilian reactor waste (already done for smoke detectors etc).

Online Blackstar

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Re: New Frontiers 4
« Reply #246 on: 11/15/2017 12:26 AM »
My understanding was Americium-241 was the next best RTG material, it can be extracted from civilian reactor waste (already done for smoke detectors etc).

There's public information on that. You can google it. The Europeans are going to use that material. Pu-238 is better, but the Europeans don't have a source, so they are going with something they can produce.

As a colleague explained to me, one of the benefits of Pu-238 is that it is not soluble in water, so if if comes down from orbit or lands in the water after a launch accident, it won't dissolve and can be recovered. I don't know if the same is true for Americium.

The U.S. government treats isotopes very carefully. There are proliferation concerns, meaning that they don't want them to fall into the wrong hands. Originally this was mostly about somebody building a nuclear bomb, but it evolved into concern about dirty bombs. That concern increased after 9/11.

Offline DarkenedOne

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Re: New Frontiers 4
« Reply #247 on: 11/15/2017 03:08 AM »
For the past four years or so, NASA has been spending something like $50 million per year to restart Pu-238 production. I believe that this year, for the first time in about three decades, they made about 700 grams of Pu-238. So, if anybody is counting, that works out to about $200 million for 700 grams of Pu-238...

But, once they get up to full production, they'll be spending about $50 million for 1.5 kilograms, so the cost will be... $50 million for 1.5 kilograms. For comparison, 1.5 kilograms of gold would cost you about $65K.

Ok sounds like what I was saying.  On top of that there are plenty of proposals for significantly increasing the yield of the production.  While tens of millions per kilogram sounds expensive they are usually a small expense compared to the larger mission. 

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Re: New Frontiers 4
« Reply #248 on: 11/15/2017 03:11 AM »
For the past four years or so, NASA has been spending something like $50 million per year to restart Pu-238 production. I believe that this year, for the first time in about three decades, they made about 700 grams of Pu-238. So, if anybody is counting, that works out to about $200 million for 700 grams of Pu-238...

But, once they get up to full production, they'll be spending about $50 million for 1.5 kilograms, so the cost will be... $50 million for 1.5 kilograms. For comparison, 1.5 kilograms of gold would cost you about $65K.

Ok sounds like what I was saying.  On top of that there are plenty of proposals for significantly increasing the yield of the production.  While tens of millions per kilogram sounds expensive they are usually a small expense compared to the larger mission. 

No, it sounds like the complete opposite of what you were saying. But carry on.

Offline Danderman

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Re: New Frontiers 4
« Reply #249 on: 11/15/2017 03:22 AM »
I can remember attending a space conference in the latter 1990s where several groups talked about their privately funded space missions. There was one--maybe you remember what it was called?--where they were going to use Soviet-era Luna lander hardware.

ISELA wanted to use ex-Soviet hardware. LA stood for Lavochkin Association, which manufactured all Soviet planetary probes since the mid-1960s

IIRC, the US side were ex-GD people. I explained to them at the time that Luna hardware required Protons to get beyond LEO, but they did not seem to mind.

Lavochkin has since demonstrated that Soyuz can be used to launch modified Luna hardware that can propel itself beyond LEO, except that it doesn't work. Yet.

« Last Edit: 11/15/2017 03:23 AM by Danderman »

Offline DarkenedOne

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Re: New Frontiers 4
« Reply #250 on: 11/15/2017 03:32 AM »
For the past four years or so, NASA has been spending something like $50 million per year to restart Pu-238 production. I believe that this year, for the first time in about three decades, they made about 700 grams of Pu-238. So, if anybody is counting, that works out to about $200 million for 700 grams of Pu-238...

But, once they get up to full production, they'll be spending about $50 million for 1.5 kilograms, so the cost will be... $50 million for 1.5 kilograms. For comparison, 1.5 kilograms of gold would cost you about $65K.

Ok sounds like what I was saying.  On top of that there are plenty of proposals for significantly increasing the yield of the production.  While tens of millions per kilogram sounds expensive they are usually a small expense compared to the larger mission. 

No, it sounds like the complete opposite of what you were saying. But carry on.

It is a massive waste of time to sit around trying to figure out how to get around using nuclear power for surface and deep space missions.  There is a reason why NASA resumed Pu-238 production.  It was unavoidable.   

All it takes is a few back napkin level calculations to see that solar irradiance for destinations beyond Jupiter simply do not make solar power viable.

Even for surface missions like to the Moon and Mars where solar power might be possible RTGs still come out as the superior option.  Remember it costs you hundreds of thousands to millions of dollars per kilogram to get to places like the Marian surface in the first place.   People who have tried to come up with systems that do not use RTGs have found such systems to be more expensive than ones with RTGs.  RTGs save you money despite their cost.

Offline plutogno

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Re: New Frontiers 4
« Reply #251 on: 11/15/2017 05:43 AM »
Lavochkin has since demonstrated that Soyuz can be used to launch modified Luna hardware that can propel itself beyond LEO, except that it doesn't work. Yet.

not entirely true. Soyuz has been used to launch (successfully) Mars and Venus Express for ESA, in both cases using Luna-derived Fregat stages.
but this is entirely OT

Offline vjkane

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Re: New Frontiers 4
« Reply #252 on: 11/15/2017 04:03 PM »

All it takes is a few back napkin level calculations to see that solar irradiance for destinations beyond Jupiter simply do not make solar power viable.
There are at least three New Frontiers (we don't know what power ELSAH is proposing to use) and one European proposals that would use solar power at Saturn.  I'm going to go with thinking the engineers on the proposing teams probably are pretty smart people.  There are almost certainly problems with using solar that far out (selecting cells for low light and low temperatures and the mass and size of the large panels), but these teams think they have solutions.  And the they decided that the tradeoffs for solar are better than the $ costs of using the offered RTGs.  (Well, not for the ESA proposal, which wouldn't have been offered an RTG.)

Assuming these guys are right, then the solar cell line falls somewhere beyond Saturn.  I haven't seen anyone proposal solar for Uranus and beyond.

Offline whitelancer64

Re: New Frontiers 4
« Reply #253 on: 11/15/2017 04:29 PM »

All it takes is a few back napkin level calculations to see that solar irradiance for destinations beyond Jupiter simply do not make solar power viable.
There are at least three New Frontiers (we don't know what power ELSAH is proposing to use) and one European proposals that would use solar power at Saturn.  I'm going to go with thinking the engineers on the proposing teams probably are pretty smart people.  There are almost certainly problems with using solar that far out (selecting cells for low light and low temperatures and the mass and size of the large panels), but these teams think they have solutions.  And the they decided that the tradeoffs for solar are better than the $ costs of using the offered RTGs.  (Well, not for the ESA proposal, which wouldn't have been offered an RTG.)

Assuming these guys are right, then the solar cell line falls somewhere beyond Saturn.  I haven't seen anyone proposal solar for Uranus and beyond.

Solar power is certainly feasible as far out as Saturn. An RTG would be a better option, both for consistency of power and weight (and it's a heat source for the probe to keep warm) ... if RTGs were available.

Missions being proposed with solar that far out are more a matter of necessity than being the superior engineering option.
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Online Blackstar

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Re: New Frontiers 4
« Reply #254 on: 11/15/2017 05:00 PM »
Solar power is certainly feasible as far out as Saturn. 

For certain definitions of "feasible."

The problem, of course, is that the farther out you go, the bigger the solar panels have to get, and simply carrying all that mass and that bulk can then limit operations. Some observations and activities become impossible because there's a giant solar array to maneuver around or it blocks your field of view or line of sight for communications.

When we did the Academies' report on restarting Pu-238 production back in 2008/9, one of the things we noted was that NASA had fallen into a nasty circle whereby Pu-238 was so precious and running out that NASA had started to rule it out for missions. This extended the supply, which had the adverse effect of making it look like they did not need to restart production. That only created more pressure not to use it--and also meant that the material that was sitting in the unused stockpile was continuing to decay. They were reaching a point where the existing material was going to be too weak to use effectively.

Some of us worried that when JPL switched to solar for Europa Clipper this could undercut the argument for restarting Pu-238 production. Fortunately, that has not happened, and one of the surprising things about EC is that the mission designers later learned that they could not have done the mission with RTGs. But managing the Pu-238 stockpile is a case of keeping one foot on the gas and the other foot on the brakes, and also not allowing people to start thinking that Pu-238 is not needed for Mars, Jupiter and Saturn missions because solar power can do it all.

Offline vjkane

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Re: New Frontiers 4
« Reply #255 on: 11/15/2017 05:12 PM »

Solar power is certainly feasible as far out as Saturn. An RTG would be a better option, both for consistency of power and weight (and it's a heat source for the probe to keep warm) ... if RTGs were available.

Missions being proposed with solar that far out are more a matter of necessity than being the superior engineering option.
NASA is making RTGs available for the next New Frontiers mission.  At least three teams chose to go with solar despite all the issues that I and others have listed.  I presume those were informed decisions by knowledgeable and smart engineers and PIs.  So far as I know, only Dragonfly, which must use an RTG under Titan's haze layers, among all the NF proposals to all targets is proposing to use an RTG.
« Last Edit: 11/15/2017 06:30 PM by vjkane »

Online Blackstar

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Re: New Frontiers 4
« Reply #256 on: 11/15/2017 06:40 PM »
I presume those were informed decisions by knowledgeable and smart engineers and PIs. 

Yes, although I would add that there have been complaints in the recent past about how NASA was allocating the costs of integrating RTGs. I don't remember the specifics, but it had something to do with the ancillary costs--like you would get the RTG for a set price, but you then had to pay to nuclear certify the launch. That might have helped push some teams to avoid the RTGs.

Offline vjkane

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Re: New Frontiers 4
« Reply #257 on: 11/15/2017 07:16 PM »
Yes, although I would add that there have been complaints in the recent past about how NASA was allocating the costs of integrating RTGs. I don't remember the specifics, but it had something to do with the ancillary costs--like you would get the RTG for a set price, but you then had to pay to nuclear certify the launch. That might have helped push some teams to avoid the RTGs.
Based on comments in meetings, price is the issue.  I'm sure that if NASA covered the RTG costs or only charged the equivalent cost of the solar alternative, then teams would love to have the compact power source that also produces a lot of spare heat to pipe around the spacecraft.

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Re: New Frontiers 4
« Reply #258 on: 11/15/2017 08:30 PM »
Based on comments in meetings, price is the issue.  I'm sure that if NASA covered the RTG costs or only charged the equivalent cost of the solar alternative, then teams would love to have the compact power source that also produces a lot of spare heat to pipe around the spacecraft.

I don't know how NASA allocated the costs of an RTG to the missions. No matter how they did it, they're not allocating full costs, because they couldn't--the infrastructure costs are huge, and dividing them into such a low production run would be killer.

For example, Cassini was launched in 1997, New Horizons in 2006, and MSL/Curiosity in 2011. So that's 14 years for two RTG-powered spacecraft (NH and MSL). How would you apportion that 14 years of infrastructure cost? Should NH pay for half of it? That would have been a few hundred million dollars--and this was before Pu-238 production was restarted, increasing the annual infrastructure cost.

For the Discovery round prior to the most recent one, NASA was going to offer the ASRG to the programs for "free," although requiring them to pay some part of the certification cost. Later the ASRG got canceled.
« Last Edit: 11/15/2017 08:30 PM by Blackstar »

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