Author Topic: Possible cost-reduction possibilities for the NASA portions of MSR  (Read 50548 times)

Offline Don2

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Hybrids have been proposed many times for various applications and have rarely if ever worked out.  Look at all the problems Virgin Galactic had with SS2.  To me, the hybrid MAV has always seemed more like it was being pushed by some people in academia to give them something to write papers about, not a real solution.

Thanks for the reference. In my original post I said 'any throttleable design' because I was also thinking about bi-prop designs. The design studies done in 2015 showed that hybrids were a little more attractive, but my recollection is that the solid design and the bi-prop design came fairly close. The fact that NASA has now abandoned the hybrid work and gone back to solids raises questions about the accuracy and value of design studies. I'll come back to that later. First I want to mention another reason that a throttleable design might be desirable, which is the surprising aerodynamic heating problems that MAV has.

https://dataverse.jpl.nasa.gov/api/access/datafile/58890?gbrecs=true
This paper about the orbiting sample mentions that the nose of the MAV will be heated to 1500K ( 2240°F) at 100s into the ascent. That is a problem for a bunch of reasons, one of which is that the samples need to be kept below 303K to avoid cooking all the interesting organic molecules. They propose to add thermal insulation to deal with the problem, but if that goes all the way to orbit then it will directly subtract from the mass of the payload. If the engine could be throttled, then I think that the MAV velocity could be managed to reduce the peak aerodynamic heating.

Offline Jim

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The fact that NASA has now abandoned the hybrid work and gone back to solids raises questions about the accuracy and value of design studies.


That would be wrong and full of hubris.  Why do you think you know better?

First I want to mention another reason that a throttleable design might be desirable, which is the surprising aerodynamic heating problems that MAV has.


Outdated document and problem.
« Last Edit: 11/29/2023 06:13 pm by Jim »

Offline Don2

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I'm starting to question the value of design studies for the MAV. None of the studies done over the past two decades predicted the current mass of 450kg. I'm starting to think that for rockets in this size range there are a lot of problems that only emerge when detailed designs are done. Perhaps the only way to discover the performance of this size of rocket is to build one and flight test it, something that has never been done.

I've looked around online for similar projects that would show that MAV-like performance is possible. There are tactical missiles with a similar mass, but their performance seems to max out at 1km/s of delta-v. (Mach 3.4) I suspect that the reason for that is that aerodynamic heating would melt any missile that tried to go much faster. Even if MAV like performance was possible for a tactical missile, it wouldn't be desirable because it would destroy the missile.

The closest analogy to the MAV project seems to be the fighter launched ASM-135 ASAT from 1985. This weighed 1200kg, achieved a delta-v of 3.3 km/s, while carrying a 13.6 kg payload. Fighter launch from 38,000ft would have required some cold tolerance, as the air temperature at that altitude is normally -56°C. This project was much heavier and somewhat lower performing than the MAV, so it doesn't give me much faith that the MAV specs are achievable. Since the mid-80s composite motor cases have been introduced for solids, which make them more expensive and somewhat better performing. I don't think there has been a dramatic change in solid motor performance.
https://en.wikipedia.org/wiki/ASM-135_ASAT
             
(Data at 0:28, payload mass mentioned at 1:51)

Offline Don2

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First I want to mention another reason that a throttleable design might be desirable, which is the surprising aerodynamic heating problems that MAV has.


Outdated document and problem.

I don't think the physics has changed. Can you provide a reference showing that this is no longer a problem?

Offline Jim

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I'm starting to question the value of design studies for the MAV.

Are you serious?   You think that they can't design a system to make it into Martian orbit?

https://www.jpl.nasa.gov/news/nasa-mars-ascent-vehicle-continues-progress-toward-mars-sample-return
« Last Edit: 11/29/2023 09:40 pm by Jim »

Offline thespacecow

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And this means the whole "but private companies can't do science mission" argument is invalid, if NASA can ask private companies to land and return astronauts from the Moon, they damn well can ask private companies to land and return samples from Mars, there is no meaningful difference.

wrong.  Science as in complex non crew missions.

Incorrect, there's no way a complex non-crew mission is automatically a science mission. By your definition every ISS resupply mission is a science mission, DM-1/OFT-1/2 is a science mission, the unmanned lunar landing of HLS is a science mission, that's just absurd. In reality all these missions are managed by HEOMD, not SMD.
« Last Edit: 11/30/2023 02:33 am by thespacecow »

Offline Don2

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I'm starting to question the value of design studies for the MAV.
Are you serious?   You think that they can't design a system to make it into Martian orbit?

https://www.jpl.nasa.gov/news/nasa-mars-ascent-vehicle-continues-progress-toward-mars-sample-return

The mass of the MAV has increased over the past few years. They got the mass back down by accepting the risk of an unguided upper stage. I think that is evidence that they have struggled with it.

Your reference indicates that the MAV has passed PDR but not CDR. My understanding is that that means that they have not completed the detailed design work. We'll see how it goes.

Offline Don2

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The paper I referenced above provides a lot of detail on the orbiting sample design. I'll repeat the reference here:
https://dataverse.jpl.nasa.gov/api/access/datafile/58890?gbrecs=true

It reveals the mass budget for the system, which is as follows: (all masses in kg)

Shell...5.7
Canister...3.1
Beacon electronics and batteries...0.3
Atmospheric sample tanks...0.3
Soil sample tubes...2.6
TOTAL...12.0

Most of the mass is structure. What is driving that? The decision to dispense with parachutes seems to be a big part of the problem. The paper says:

'The impact landing is one of the largest challenges for the structural design of the OS...... in accordance with NPR 8020.7G [2], extraordinary efforts are being made to ensure no Martian material is accidentally released from the OS even in the low probability event of a hard off-nominal impact. The OS structure must be very tough to minimize the possibility of tertiary damage or breach of the redundant containment systems in the EEV.'

It also states:
'The OS and the core sample tubes must withstand the expected 1300 g nominal Earth-landing loads imposed during the parachute-less landing. '

Given the way that parachute-less landing is driving up the mass of the OS, the MAV and the lander, I really have to wonder if that was a good design decision. It seems likely to me that if the OS did not have to cope with a 1300g impact then it could be made lighter, and that would cut the cost of the entire project. It also seems probable to me that the decision to adopt a parachute-less landing was the main reason that the mass of the orbiting sample increased from the original 5kg to the present 12kg.

In general the requirements on the OS need to be reduced as much as possible. It travels all the way to the surface of Mars and back, which makes it the single most expensive place to add capability.

Another possibility could be to reduce the number of sample tubes returned. In 2013 ESA built a prototype OS, which stored 11 sample tubes and weighed less than 5kg.

Offline Jim

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And this means the whole "but private companies can't do science mission" argument is invalid, if NASA can ask private companies to land and return astronauts from the Moon, they damn well can ask private companies to land and return samples from Mars, there is no meaningful difference.

wrong.  Science as in complex non crew missions.

Incorrect, there's no way a complex non-crew mission is automatically a science mission. By your definition every ISS resupply mission is a science mission, DM-1/OFT-1/2 is a science mission, the unmanned lunar landing of HLS is a science mission, that's just absurd. In reality all these missions are managed by HEOMD, not SMD.

wrong.  a.  ISS resupply is not complex.  B.  OFT is a launch vehicle test.  C.  HLS is not hands off private.

Offline Jim

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Given the way that parachute-less landing is driving up the mass of the OS, the MAV and the lander, I really have to wonder if that was a good design decision. It seems likely to me that if the OS did not have to cope with a 1300g impact then it could be made lighter, and that would cut the cost of the entire project. It also seems probable to me that the decision to adopt a parachute-less landing was the main reason that the mass of the orbiting sample increased from the original 5kg to the present 12kg.


It is a good decision because OS has to survive a 1300g impact regardless in case the parachutes fail.  And since it has to do that, no sense in having the parachutes in the first place.

See?  Why do you think you know better?  First you question whether they can design the vehicle, then you question their decisions when you aren't close seeing the big pictue.
« Last Edit: 11/30/2023 02:21 pm by Jim »

Offline thespacecow

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And this means the whole "but private companies can't do science mission" argument is invalid, if NASA can ask private companies to land and return astronauts from the Moon, they damn well can ask private companies to land and return samples from Mars, there is no meaningful difference.

wrong.  Science as in complex non crew missions.

Incorrect, there's no way a complex non-crew mission is automatically a science mission. By your definition every ISS resupply mission is a science mission, DM-1/OFT-1/2 is a science mission, the unmanned lunar landing of HLS is a science mission, that's just absurd. In reality all these missions are managed by HEOMD, not SMD.

wrong.  a.  ISS resupply is not complex.  B.  OFT is a launch vehicle test.  C.  HLS is not hands off private.

a. That's just semantics, it's certainly more complex than most unmanned space missions. It's more complex than small science missions like SIMPLEx and probably comparable to a Discovery class mission, just goes by the amount of development funding involved.
b. I'm referring to Starliner's OFT, it's not a LV test. Also you didn't say it can't be a unmanned test mission.
c. I never said it would be hands off, I'm saying private company can do this, NASA insight and/or oversight is not ruled out.

The whole idea of "Science as in complex non crew missions" is just useless gatekeeping, it should be obvious to anyone who doesn't have a bias against private space that the sample retrieval and return part of MSR is not a science mission, Casey Dreier and Orlando Figueroa all but admitted this on air.
« Last Edit: 12/01/2023 05:58 am by thespacecow »

Online VSECOTSPE

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The more NASA uses proven technology, the less it pushes tech forward.

NASA is supposed to “expand the boundaries of our technological capabilities to explore our solar system,” according to NASA itself.

Planetary scientists are not the only stakeholder.

For all intents and purposes, the science community is _the_ customer for MSR.  MSR would not exist and the USG would not be spending taxpayer dollars on it if it was not the top priority in a National Research Council decadal review of planetary science priorities.

Yes, by law NASA is supposed to advance more than science.  And it does.  We just don’t risk top science objectives by putting unproven systems, techniques, and technologies on the critical path to those top science objectives except when absolutely necessary.   MSR already has to land the biggest payload to date on Mars, land about an order of magnitude more precisely than any prior Mars mission, prove out the first launch from the surface of Mars, and prove out the first rendezvous and docking in Mars orbit.  It doesn’t need more “go proves”.

Flight technology demonstration is what STMD missions and much smaller SMD missions are for.  Yes, STMD is arguably mismanaged and tech demos are perennially underfunded, but we shouldn’t fix that by introducing unnecessary technical risk into priority science missions.  (I say that having helped staff NASA’s Office of the Chief Technologist in a prior life.)

ISRU saves less mass than I hoped.

It doesn’t matter what it could save.  For all intents and purposes, propellant production at Mars is unproven.  We all love to hear Zubrin rant about ISRU, but it’s not going to be put on the critical path to MSR.

Would it be good if NASA had pushed harder on ISRU in prior decades?  Yes.  Is it kind of pathetic that SX may become the org that demonstrates propellant production at Mars and not NASA?  Yeah.  Is putting this major tech demo in the critical path to MSR going to reduce the costs and risks of MSR?  Heck no.

One of the options they look at is a hybrid rocket with HTPB/Al fuel and LOX oxidizer produced via ISRU.

Liquids involve pressurization and/or pumping.  That gives them failure modes that solids don’t have, especially in an austere environment gazillions of miles from Earth.  There’s a reason military munitions and missiles use solids — they go off reliably, even in bad conditions.  It terms of system simplicity, it’s the difference between lighting a firecracker and pressurizing a tire.  Or lighting a firecracker and starting a sump pump.  MSR needs simplicity and reliability, not unnecessary complexity.  KISS principle.  (Also, if you were worried about maintaining cryogenic propellants on lunar lander missions for a couple weeks like in a prior thread, you should definitely be worried about maintaining cryos for years to/at Mars.)

Per Figueroa, the problem with the MAV and other MSR systems isn’t that their mass budgets don’t close.  It’s that they never settled on a sample size and have been spinning their wheels, years, and billions closing and reclosing around an ever-moving target.  That has to stop. 

You seem to not understand how the proposed MAV launches. It is similar to the man-portable FGM-148 Javelin anti-tank missile.

A dual impulse solid motor ignites the missile inside a disposable launch/carrier tube. The smaller initial propellant charge ejects the the missile from the tube at low velocity.

MAV is not like Javelin.  There is no kick motor.  The MAV is tossed mechanically before firing to orbit.

But that's not really the case here. They're not building a Webb. Just a handfull of rockets that really shouldn't be taking more than constructing a modern aircraft carrier. Talking about 10 billion not being enough to do the job is just insane.

No, MSR has to push boundaries and demonstrate firsts just like JWST.  MSR is more than just a collection of rockets.  It’s a collection of rockets that must enter and decelerate in the thin Martian atmosphere with a higher mass than has been demonstrated before.  That must land about an order of magnitude more precisely on the Martian surface than has been demonstrated before.  That must launch from the Martian surface back to Mars orbit, something that has never been demonstrated before.  That must find, rendezvous with, dock with, and transfer samples to a spacecraft in Mars orbit, something that has never been demonstrated before.  That must renter the Earth’s atmosphere from a Martian trajectory and land the samples safe back on Earth, something that has never been demonstrated before.

It may or it may not, you never know until you work on it. As I said before, NASA is going to have to figure this out soon anyway, it'll certainly be needed before the unrealistic 2030 launch date of POR MSR.

It’s not a question of “working on” or “figuring out” the planetary protection requirements.  The guidelines have been set internationally and the US has accepted and uses them.

You hold out the hope that these requirements might be relaxed in the future.  I’m saying that’s unlikely to be the case with Jezero Crater (or however the area of research interest is defined), especially if something scientifically interesting (organic chemistry, microbiology, etc.) is found.  In that case, the requirements will go up because the last thing the research community will want is Earth microbes confusing the already complex data and information they’re trying to extract from that region.

Don't want to be drawn into a side way discussion, the point here is that SpaceX has taken a technology from TRL 3 all the way to TRL 9 (and bonus point being this technology has relevance to Mars EDL too)

All sorts of organizations in the aerospace sector have taken all kinds of technologies from low to high TRLs.  The question is whether to put something that is low TRL on the critical path to MSR when that thing is not needed to pull of MSR.  Pressing the “just buy a Starship” button ignores the fact that Starship introduces unproven systems, technologies, and techniques — supersonic retropropulsion in the Martian atmosphere, propellant production on the surface of Mars, restarting liquid engines on the surface of Mars, supersonic retropropulsion in Earth’s atmosphere from a Martian trajectory — into MSR that are not needed to pull off MSR.  Would it be good if NASA and SX were working to demonstrate these capabilities for future Mars/solar system exploration?  Yes, absolutely.  Should they be on the critical path to getting a couple kilograms of Mars samples into scientists’ hands?  Heck no.  They introduce substantial, additional, unnecessary technical risk into a priority science mission that already has a number of technically risky hurdles to overcome.

The “just buy a Starship” button also ignores the reality that Starship is way too big and too exposed to meet the planetary protection requirements for a lander or other system at Jezero.  It’s a non-starter from that perspective.

Right, it's not like MSR is facing a money problem.... Oh wait, it is

The “just buy a Starship” button could make sense if Starships were shuttling back and forth from Earth to Mars.  Maybe then we could buy one for a couple hundred million bucks or even a couple billion, park it and it’s propellant production unit far out of the Jezero exclusion zone for planetary protection, spend a couple billion more on a really long-range rover to grab the samples, and pocket the savings.

But SX is not there yet with Starship.  It’s going to take many more years of development and demonstration and billions of dollars of more investment to get Starship to the level of maturity where it could offer risk reduction and cost savings over a conventional MSR architecture.

Is it worth having he discussion with SX and other orgs?  Yes, who knows what techniques or systems or areas of co-investment could be out there that would help simplify MSR’s problems and help out SX or another org.

But will buying a Starship to Mars and back reduce MSR costs and risks for the foreseeable future?  No.

So it's incorrect to think the sample retrieval and return part of MSR as a science mission, it is not. It's a space transportation mission, no different from an Apollo or Artemis landing, in fact it has less science than a typical Apollo or Artemis landing because in the lunar landings they actually carry science instruments.

And this means the whole "but private companies can't do science mission" argument is invalid, if NASA can ask private companies to land and return astronauts from the Moon, they damn well can ask private companies to land and return samples from Mars, there is no meaningful difference.

The label — science or transport — doesn’t really matter.  What matters is that it’s a mission that already has to do things that have never been done before.  Largest payload to the Martian surface than before.  Order of magnitude greater landing precision than before.  First launch from the surface of Mars.  First rendezvous and docking in Mars orbit.  The “just buy a Starship” button or something like it doesn’t reduce those challenges.  It just complicates them.  It adds an EDL technique that has never been demonstrated at Mars.  It add propellant production that has never been demonstrated at Mars.  It adds relighting liquid engines from the surface of Mars.  It replaces rendezvous and docking in Mars orbit with an EDL technique in Earth’s atmosphere that has never been demonstrated from a Mars trajectory.  And then there’s the planetary protection issue.

Again, should JPL and NASA be talking to SX and other orgs to see if there are solutions that could reduce the size and complexity of an MSR lander or cost-sharing opportunities that would benefit both sides?  Sure.  But the answer is not buying billions of additional dollars and years of Starship development for Mars.  Unlike Artemis and lunar crews, that’s not necessary to pull off MSR.

Offline Don2

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ISRU saves less mass than I hoped.

It doesn’t matter what it could save.  For all intents and purposes, propellant production at Mars is unproven.  We all love to hear Zubrin rant about ISRU, but it’s not going to be put on the critical path to MSR.

Would it be good if NASA had pushed harder on ISRU in prior decades?  Yes.  Is it kind of pathetic that SX may become the org that demonstrates propellant production at Mars and not NASA?  Yeah.  Is putting this major tech demo in the critical path to MSR going to reduce the costs and risks of MSR?  Heck no.

One of the options they look at is a hybrid rocket with HTPB/Al fuel and LOX oxidizer produced via ISRU.

Liquids involve pressurization and/or pumping.  That gives them failure modes that solids don’t have, especially in an austere environment gazillions of miles from Earth.  There’s a reason military munitions and missiles use solids — they go off reliably, even in bad conditions.  It terms of system simplicity, it’s the difference between lighting a firecracker and pressurizing a tire.  Or lighting a firecracker and starting a sump pump.  MSR needs simplicity and reliability, not unnecessary complexity.  KISS principle.  (Also, if you were worried about maintaining cryogenic propellants on lunar lander missions for a couple weeks like in a prior thread, you should definitely be worried about maintaining cryos for years to/at Mars.)

Per Figueroa, the problem with the MAV and other MSR systems isn’t that their mass budgets don’t close.  It’s that they never settled on a sample size and have been spinning their wheels, years, and billions closing and reclosing around an ever-moving target.  That has to stop. 

I agree with most of that. However, liquids like hydrazine and nitrogen tetroxide have been used in long lived space propulsion systems. Solids aren't so simple on Mars because they tend to crack at low temperatures.

I thought the sample size goal for MSR was 32 tubes. I'm not convinced the mass budgets close for that. I have seen numbers ranging from 10 tubes to 32 tubes from different sources.

Online VSECOTSPE

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Opinion: Zubrin Says Rethink MSR

Quote
Let us consider the alternative. For the same $10 billion now projected to be spent on the MSR mission over the next 15 years, we could send 20 missions averaging $500 million each in cost. These could include landers, rovers, orbiters, drillers, highly capable helicopters, and possibly balloons or other more novel exploration vehicles as well. Instead of being limited to one exploration site, these could be targeted to 20 sites and carry a vast array of new instruments provided by hundreds of teams of investigators from around the world.…

Let’s look at the numbers. In its history, NASA has flown 25 spacecraft to Mars, of which (if we include the Ingenuity helicopter in the count) 20 have been successful. That is a mission success probability of 0.8. The European Space Agency’s Mars spacecraft track record is two out of four, for a mission success probability of 0.5. The MSR mission, as currently conceived, includes two new NASA spacecraft (the sample return lander and the ascent vehicle), and one ESA spacecraft (the orbiter that will collect the sample in Mars orbit and return it to Earth.) If any of those three spacecraft fails, the mission fails. That means that to calculate the probability of mission success, one must put the success probability of each into series, and multiply them together. That means that, based on the individual risk presented by each of the principal flight elements alone, the overall probability of mission would be 0.8 x 0.8 x 0.5 = 0.32 or about one in three.

https://spacenews.com/rethink-the-mars-program/

Offline Jim

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I agree with most of that. However, liquids like hydrazine and nitrogen tetroxide have been used in long lived space propulsion systems. Solids aren't so simple on Mars because they tend to crack at low temperatures.


What you agree to is irrelevant.

Liquids aren't so simple on Mars because they tend to freeze at low temperatures.
« Last Edit: 12/07/2023 10:09 pm by Jim »

Online VSECOTSPE

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I agree with most of that. However, liquids like hydrazine and nitrogen tetroxide have been used in long lived space propulsion systems.

You were talking about a LOX system upthread.

Quote
I thought the sample size goal for MSR was 32 tubes. I'm not convinced the mass budgets close for that. I have seen numbers ranging from 10 tubes to 32 tubes from different sources.

Per Figueroa, the program has yet to settle on a sample size.  That’s really dumb after this much time and this many dollars.  But doesn’t mean that a solid fuel MAV can’t close on any of those sample sizes.

Read Figueroa’s report.

Offline Dalhousie

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Opinion: Zubrin Says Rethink MSR

Quote
Let us consider the alternative. For the same $10 billion now projected to be spent on the MSR mission over the next 15 years, we could send 20 missions averaging $500 million each in cost. These could include landers, rovers, orbiters, drillers, highly capable helicopters, and possibly balloons or other more novel exploration vehicles as well. Instead of being limited to one exploration site, these could be targeted to 20 sites and carry a vast array of new instruments provided by hundreds of teams of investigators from around the world.…


https://spacenews.com/rethink-the-mars-program/

Or three or four high end rovers.  I am a great supporter of MSR for all the usual reasons, but I find this thought provoking.  Especially when we are beginning to narrow down locations from which Mars meteorites have been ejected.

Apologies in advance for any lack of civility - it's unintended

Offline Emmettvonbrown

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"Well, Europe ain't a reliable partner, then - screw them and screw MSR, and let's go back to Goldin Faster, Better Cheaper."

Nice for Europe, Robert. So classy.

Sorry, but I hoped for a more detailed strategy... a longer paper, at least. It's just like "ding dang doo, screw Europe and screw MSR and start from scratch, and all will be fine."

The basis thesis may be sound - more Mars missions the cheaper way. The plan and execution is - ugh. Also the probability calculations - WDH. 

« Last Edit: 12/08/2023 01:25 pm by Emmettvonbrown »

Offline freddo411

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.. snip ..

The label — science or transport — doesn’t really matter.  What matters is that it’s a mission that already has to do things that have never been done before.  Largest payload to the Martian surface than before.  Order of magnitude greater landing precision than before.  First launch from the surface of Mars.  First rendezvous and docking in Mars orbit.  The “just buy a Starship” button or something like it doesn’t reduce those challenges.  It just complicates them.  It adds an EDL technique that has never been demonstrated at Mars.  It add propellant production that has never been demonstrated at Mars.  It adds relighting liquid engines from the surface of Mars.  It replaces rendezvous and docking in Mars orbit with an EDL technique in Earth’s atmosphere that has never been demonstrated from a Mars trajectory.  And then there’s the planetary protection issue.

Again, should JPL and NASA be talking to SX and other orgs to see if there are solutions that could reduce the size and complexity of an MSR lander or cost-sharing opportunities that would benefit both sides?  Sure.  But the answer is not buying billions of additional dollars and years of Starship development for Mars.  Unlike Artemis and lunar crews, that’s not necessary to pull off MSR.


So the traditional MSR development pathway needs to create/deploy many new technologies ... so does starship.   The argument that new MSR development + tech + architecture + management is somehow magically superior to new Starship technology falls flat. 

The present claim is that MSR will be developed and built for a launch readiness date of 2028.   The review board says:  " near zero probability of ERO/CCRS or SRL/MAV meeting the 2027/2028 Launch Readiness Dates (LRDs) "    LDR for 2030 should be considered unlikely as well, considering the technical and management problems.   JWST provides a good example of a likely outcome of a large traditional development program like MSR

OTOH, There are reasonable expectations that Starship will have flown Lunar missions by 2028.   Successful Lunar starship missions will demonstrate a TRL of 9, a feat that will simply not occur with traditional MSR, because the traditional development scheme doesn't attempt to fly hardware prior to the initial mission.   Actual flight demonstrations should be weighted very, very high when comparing MSR vs. alternative architectures.

Lastly, it's not desirable or necessary to build a mars return architecture that does only the bare minimum.   If a container ship is available to move a package, there's no need to custom build 2 boats to rendezvous and cross the pacific.   Using a common, frequently used transportation system is a more reliable, likely cheaper alternative.

Online VSECOTSPE

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I was just impressed that Zubrin could write about something without invoking ISRU...

More seriously, no doubt, there are several problems with Zubrin’s opinion piece.  The treatment of mission risk is superficial.  The kinds of missions that could carry out an in situ search for life are probably more like $2 billion per, not $500 million per.  And whether it’s five or 20, there’s no institution to handle the development and operation of so many Mars missions in parallel.

That said, Zubrin raises a philosophical, 50K ft altitude discussion that is reminiscent of conversations I had with NASA when covering the space science account at OMB in the wake of the MCO/MPL failures. Recognizing even back then rapidly advancing technologies in biomedical instrumentation, sensor miniaturization, and computing and communications, the Space Science AA (Ed Weiler) and I talked about “carpet bombing” Mars with scores of in situ research platforms in the search for extinct/extant life.  We were both trained as astrophysicists, and our musings didn’t matter in the end as the planetary science community made clear that getting samples in their Earth labs was still the end goal, now guided by a follow-the-water strategy from Program Scientist Jim Garvin (or someone that Garvin lifted it from).  But I still wonder “what if” and whether an in situ strategy that leverages rapidly advancing technologies won’t someday be revisited if/when the tougher and fairly static technologies underpinning MSR once again run into a wall.

FWIW...

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