16 thoughts on “Mars Sample Return”

  1. The irony of having commercial human settlers from SpaceX go pick them up and stuff them into a robotically landed MAV at a fraction of the cost to NASA never ceases to amuse me.

  2. At some point we need to start demonstrating the ability to “live off the land”, and stop depending on EVERYTHING being shipped from KSC is ready-to-use form.

    This seems like an interesting first step. The engineers on these missions have shown an ability to do lots with their robots, (witness the Mars helicopter), so why not take another step and start with simple manufacturing from an abundant resource? (Besides, removing the CO2 from the Martian atmosphere would help the Martian Global Crisis Change Warming problem. )

        1. And just how, exactly, do you keep it liquid for a couple of years? That’s a lot of boil off.

          Then there’s the problem of gathering up enough smoke to make it into charcoal with only the energy from a few solar cells in a place that is rather hostile to them without much sunlight. You’re going to be climbing the steep side of the energy hill from the very bottom.

          Don’t forget that both the methane and lox are cryogenic and will have to be stored until lift off.

          Those hypergolics are looking better and better. Or you could ask Elon to FedEx them.

          Not that a project premised on using as many different organizations as possible, many phenomenally unproductive and inefficient, is likely to do more than burn prodigious stacks of money.

      1. Good point. 78 kg of Hydrogen takes a 952,000 liter tank in gaseous form or a 1200 liter tank in liquid form. If I did the math right. I wonder why Zubrin used mass rather than volume? Playing games with numbers? Sounds like a separate lander to me.

        1. I guess had separate lander just for rocket that gets sample back to earth. And another lander to make rocket fuel.
          It seems to me, you could recover H2 boil off in another spherical tank which can take some pressure. And tank starts with liquid nitrogen, which is vented [and maybe used for cold thrusters, and when empty, vent H2 into it.

        2. 1200 liters is not that large, really. I have a 1200 liter (300 gal) spare fuel tank at my ranch for gasoline, it’s about 72x38x38 freedom unit inches.

        3. Switching over to MMH/NTO bi-propellant I come up with a back-of-the-envelope calculation of the tank requirements assuming optimum 1.69 OF ratio and using the same math source for mass to volume. Based on Dr. Zubrin’s total mass number of 477 kg I figure 138 liters of MMH and 233 liters of NTO. Assuming a generous 8 kg (10 liters) of LN2 as pressurizer (1:694 expansion ratio at 20C, obviously less on Mars). For a total tank volume of 381 liters (101 gallons rounded) across three tanks. The nitrogen tank requirement just assumes assent stage pressurization, but you might want a bigger tank if it’s also used for cold gas maneuvering thrust during both descent and ascent. You get great expansion ratios with it.

          IANAAE, so your numbers may vary….

      1. Bragging rights and first dibs on any new tech

        Also, so what if SpaceX does? The point of the exercise, for all of NASA’s (much more than $10-billion) price tag is getting a sample from Mars to earth. When SpaceX does that, so what if it was SpaceX for $100mil and not the usual panopoly of NASA wastrels for (much more than) $10-billion?

  3. NASA for a long time has had the attitude that if you spread the work out enough, it will be impossible to cancel.
    This was happening as long ago as Mercury. It’s pretty much inherent to the organization’s DNA now.
    It turns out though, that if you spread it that thin, nobody gets enough to get really worked up if it’s cancelled.

    Certainly the number of organizations involved in MSR would make it almost impossible to actually work and deliver anything. All budget gets used up in coordination activities, leaving none for the actual work.

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