Quote from: thespacecow on 04/01/2025 05:16 amHe's more qualified than 99% of the person here.It's funny some people here claim if you don't work in the industry then you're automatically "wrong", yet when I quote from people actually in the industry right now (instead of 20 years ago), the objection changed to "no, he's not in the right field..."I can’t speak to what other folks have told you in the past. But whatever they wrote doesn't change the fact that Lee is a planetary scientist who made his bones calculating cratering rates, not an aerospace engineer who made his bones calculating mass fractions.
He's more qualified than 99% of the person here.It's funny some people here claim if you don't work in the industry then you're automatically "wrong", yet when I quote from people actually in the industry right now (instead of 20 years ago), the objection changed to "no, he's not in the right field..."
Quote from: thespacecow on 04/01/2025 05:16 am1. When I advocated refueling the Starship lander in Mars orbit, it's not even in the context of doing MSR.Yes, it was. You quoted this from another poster at the start of your post 390 in the other thread where you discussed refueling Starship in Mars orbit with another Starship. They were explicitly discussing the “context of MSR”.Quote from: matthewkantar on 03/06/2024 07:59 pmPeople keep talking about starship in low Mars orbit. How would that be helpful in the context of MSR? Per the study source selection, refueling Starship in Mars orbit was never part of the SpaceX study for MSR.
1. When I advocated refueling the Starship lander in Mars orbit, it's not even in the context of doing MSR.
People keep talking about starship in low Mars orbit. How would that be helpful in the context of MSR?
Quote from: thespacecow on 04/01/2025 05:16 amThat's not using round-trip human Mars missions to retrieve MSR samples, it's using unmanned test landing and takeoff - which precedes human Mars mission - to do MSR. The takeoff part is basically the same thing as SpaceX's proposal of using Starship as MAV.But that’s not what you proposed. In post 590 in the other thread, you wrote that this was the same as your post 74 in that thread. And in post 74, you argued for using Starship to do the entire MSR mission, same as a manned Mars Starship mission or an unmanned precursor:Quote from: thespacecow on 11/06/2023 02:33 amJust use a uncrewed version of your crewed Mars architecture to do MSR. You're going to have to do uncrewed test flight of this architecture anyway, so adding sample return is just a bonus...Remember the US moon rocks were also brought back by a crewed architecture, albeit via crewed mission instead of uncrewed mission.Again, per the study source selection, SpaceX never proposed replacing MSR with an unmanned dry run of their manned Mars Starship architecture.
That's not using round-trip human Mars missions to retrieve MSR samples, it's using unmanned test landing and takeoff - which precedes human Mars mission - to do MSR. The takeoff part is basically the same thing as SpaceX's proposal of using Starship as MAV.
Just use a uncrewed version of your crewed Mars architecture to do MSR. You're going to have to do uncrewed test flight of this architecture anyway, so adding sample return is just a bonus...Remember the US moon rocks were also brought back by a crewed architecture, albeit via crewed mission instead of uncrewed mission.
Yes, you know when aerospace engineers actually examined Starship for MSR? It's when NASA assembled the review team to examine MSR industry studies, and after review they accepted Starship as an option for MSR. Yet you dismissed that as well.
You have no idea what the context even is.
Of course they proposed replacing MSR with an unmanned dry run of their manned Mars Starship architecture, they proposed using Starship as MSR Mars lander and potentially as MAV, which is literally a unmanned dry run of their manned Mars Starship architecture,
Asked by the committee’s chairman, Sen. Ted Cruz (R-Texas), if the Mars Sample Return program should be “outsourced to industry,” citing a proposal to do so from Rocket Lab, Isaacman offered a one-word response: “Yes.”
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The fact that it is the largest demonstrated landing method for Mars helps.
the White House’s Office of Management and Budget (OMB) dropped a budgetary bombshell, proposing to cut NASA’s top-line funding by a quarter, slash the space agency’s science budget by nearly half and entirely eliminate MSR. The cancellation is justified, the OMB document claims, because MSR is “grossly overbudget” and its goals of sample return will instead “be achieved by human missions to Mars.”
Yes I understand that is the main reason. I've read that the heritage MSL design would have to be scaled up by about 20% to accommodate MSR. Which is almost exactly what needed to be done when the Pathfinder system was scaled up for MER. That turned in to an almost complete redesign. There has to be a risk that the same would happen with Skycrane, and if you're going to do that much development, why not just switch to a more conventional lander platform? Obviously smarter people than me have decided that an enlarged Skycrane makes the most sense. I'm just wondering if there are other, technical, advantages, rather than the heritage argument.Of course in the current budgetary environment it's likely all moot.
This is what I've been saying all along, no point of an MSR mission if we are sending humans to Mars anyway.
My hypothesis is that there are subtle and very difficult to solve problems in the 'conventional' approach that uses a rocket powered descent and landing legs. I suspect that there are very complicated interactions between the lander, the legs, the exhaust plumes and the ground which make the conventional approach hard.
When the mass of the MAV increased JPL did try to design a much larger conventional lander. The effort failed when it became apparent that they had badly underestimated the mass of the landing legs.
I would also point out that engineers have gone to great lengths to find alternatives to the conventional approach. Despite the success of Viking, they used airbags for the MER rovers and the skycrane for MSL.
Quote from: jstrotha0975 on 05/10/2025 02:59 pmThis is what I've been saying all along, no point of an MSR mission if we are sending humans to Mars anyway.I'd point out that there is no significant money for a man to Mars program in the 'skinny' budget. There is $1 billion in funding which is enough for a few design studies but that is an order of magnitude less than what a serious manned Mars effort requires even if you are very optimistic about how cheaply SpaceX can do it. They added $113 billion to defense so the money was there for a manned Mars program if the will was there to do it. The political system obviously has no interest in funding it...ever.Returning the samples would require sending humans to Jezero Crater. Landing thousands of kilometers away in another part of Mars won't do. Jezero is higher and colder than landing sites along the equator so a manned landing might want to go somewhere else. A manned landing would also contaminate the area with organic molecules which would make analysis of the samples harder and could potentially obscure evidence for Martian biology.
Starship is getting $1 billion for a dozen launches and Starship HLS for Artemis 4. This is around the same needed for a couple one-way mars launches.
