[AR] Re: big rockets

  • From: Rand Simberg <simberg@xxxxxxxxxxxxxxx>
  • To: arocket@xxxxxxxxxxxxx
  • Date: Wed, 6 Oct 2021 17:16:43 -0700

Decades ago, I was talking to people at JPL about massively parallel exploration with mass-produced rovers. But they couldn't break out of the one-off mindset. And imagine what we're going to do sending flocks of cubesats with motherships to the ocean moons. Yuri Milner may actually be planning that for Enceladus. I put a bug in Pete's ear about that.

On 10/6/21 16:33, Doug Jones wrote:

I wrote the following last year-

I think most people don't see the revolution that SpaceX's Starship will usher in. Most of the extreme cost of those Mars missions was in the non-recurring expense of building low mass bleeding-edge one-off hardware.

When you can put 100 tons into LEO for a few million dollars, most of that goes out the window. Rovers will be bulky, have four times the mass, and look like something out of Junkyard Wars. They can be built in groups of 5-10 for pennies on the dollar.

Computer array? Build a 5x redundant system using standard rack mount hardware and put it in a pressure can with tungsten shielding to get the single event upset rate down to something that can be handled routinely.

Cameras? Get a few top-of-the-line mirrorless DSLRs, put them in another pressure can with a good window, done. Sure it has ten times the mass of the exquisitely optimized jewelry on Perseverance, but who cares?

RTGs? Just put huge solar arrays on the rover. Massive things, overbuilt, rugged, with built-in compressed gas nozzles to blow the dust off as needed. A vacuum pump feeds an oilless air compressor- or rather, two of each. Maybe a robotic arm with a whisk broom. Or both systems.

Drive train? Baja Rally buggy with major parts machined down to add a little lightness but not too much. Install boots over the articulated sections to keep the dust out. Send the vehicles in pairs with winches and tow straps.

Lather, rinse, repeat. Much smaller university consortia, working with existing smallsat builders, can go wild. With delta-V to (literally) burn, missions to the outer planets won't take a freaking decade to get there, either.

Brute force all the way. It'll be glorious.

On Wed, Oct 6, 2021 at 5:05 PM Rand Simberg <simberg@xxxxxxxxxxxxxxx> wrote:

    Actually, it's available now, but only for subcribers:
    https://www.thenewatlantis.com/publications/walmart-but-for-space

    It will be out from behind the paywall in a few weeks.

    On 10/6/21 07:38, Rand Simberg wrote:

     I have an essay on this in the current issue of The New
    Atlantis. It should be available on line soon.

    On 10/6/21 06:28, Doug Jones wrote:
    Perzackly. Who needs fancy-shmancy custom rad-hard featherweight
    liquid-cooled vacuum-rated electronics when you can buy standard
    19" rack mount packages, put 'em in a steel pressure hull an
    inch thick with a polyethylene liner to catch the secondaries,
    blow the cooling fans through a flat plate heat exchanger, and
    call it good?

    We're talking _literal_ battleship construction.

    On Wed, Oct 6, 2021 at 1:22 AM J Farmer <jfarmer@xxxxxxxxxxxxx>
    wrote:

        I think one of the points being overlooked, inadvertently or
        not, is the
        sea change that the shear lift capacity StarShip will in
        have in size
        and mass.  To date, every payload has to watch every kg,
        every cubic
        cm.  What happens when you can throw another cubic meter,
        lift another
        100kg mass at a problem?  How much time and money will be
        saved when you
        don't have to sweat that last one percent of your lift budget?

        As Henry pointed out in an earlier thread about dealing with
        atmospheric
        & water leaks, with reliable lift schedules, just lift
        enough to
        replenish for several cycles while fixing the problem.  What
        changes in
        your planning when that supply run can be 50 or 100 tons of
        air or water?


        John

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