Enginering Process planning | General | Forum

brmj said:I like this aproach as well. I don't think cash prizes are an option at this point, though, and I am not sure what it would do to the culture of open collaboration we are trying to cultivate to offer cash prizes internally.

Having thought about it more, I think a cash prize for this is probably a bad idea.  The overall competig proposal idea, though, I think is a good once and I think our next big IRC meeting should focus on the details of this as one of its higher priorities (although the agenda for the meeting is quite large so we shouldn't neglect too much else for the sake of this).

Sorry I've not been as active lately as I usually am.  This might continue for a while.  Anyway, some more thoughts on the CLLARE proposal process:

First of all, with regards to what proposals must include, some basic ideas:

• A proposal name
• Brief overview of entire proposal (one or two paragraphs at most)
• A list of core hardware items involved (e.g. CM, OSM, PM, LL for "Old Cllare")
• Basic flight plan: is the proposal direct ascent, Earth orbit rendezvous, Lunar orbit rendezvous, or a mixture of these?  What does lunar landing look like?
• Explanation of candidate reentry mechanisms: Ballistic?  Parachute?  Paraglider?  Ballute?  MOOSE?)
• Proposed launch vehicle (must be an existing vehicle available for commerical launch – the Falcon 9 should count as existing)
• Calculations (using the rocket equation) showing the proposal can reasonably fit on its proposed launch vehicle.  These don't need to be super precise, but they should be fairly realistic and not rely upon extremely optimistic estimates of hardware masses.  Maximum Isp which may be assumed is 450 s.

A proposal may include anything else that the people working on it think will improve the chances of it being selected, but the above is the mandatory bare minimum.  Any proposal which doesn't get the above sorted out by the day that voting opens will not be in the running.  It should also be noted that very fine details, like navigation hardware, etc., are not, I think, really appropriate for locking down at the proposal stage.  That stuff will be figured out using the Design Task Tree voting system.  The function of the proposal system is to lock down the high-level details of the project so that the Design Task Tree system can be set up.  For this reason, at the proposal stage, the "new" CLLARE plan should not speak of the spherical nature of its CM.  Instead it should merely emphasise that the CM doubles as a lander (which is the core of the plan).  CM shape can be decided using the tree system later.

Second of all, a more general thoughts: I am slightly concerned that we might not get a lot of new proposals coming in from our community (who are fairly quiet, at least for now).  It would make the proposal system somewhat silly and a waste of time if there ended up being precisely two proposals, the "old" one and the "new" one that has motivated the proposal system, and all we worked on from here on in was the "new" proposal.  To help counter this, perhaps we should "seed" the system with some very preliminary ideas and let the community expand on ones it finds interesting.  Some ideas:

• The "ultra lightweight" approach that is advocated by Open Luna and by MicroSpace (a GLXP contender) – no spacecraft per se, the astronaut spends the whole trip in a pressure suit, seated/strapped in a minimalist, open-cab frame that provides propulsion and communications (example image).  I am not a huge fan of this approach, personally, but it does represent the ultimate embodiment of our Design Philosophy, so we should, I suppose, not exclude it without doing the research to confirm that it is not appropriate.  One nice thing about it is that the "spacecraft" would have such little mass we could probably replace LOX/LH2 liquid engines with hybrid rockets.
• Something based around the concept of inflatable habitats, like the very successful Genesis modules of Bigelow Aerospace.  A CLLARE proposal with an inflatable (or partially inflatable) CM and/or LL would be very interesting, possibly helping significantly to keep vehicle mass down.
• Something based on the idea of high horizontal velocity landing.  This would involve landing on the moon with significant horizontal velocity (but minimal vertical) and using skids, an air cushion, the lander structure or some combination thereof to "skid" to a halt.  This certainly makes safety/reliability more difficult, but it could potentially save us a lot of mass in the form of lander propellant.  This plan would require a landing site with a long stretch of clear ground to land on – maybe we can find something like this using Google Moon or the like?

A final consideration: How long do we want to give the community time to develop proposals before we call a vote?  We need to allow enough time for all the proposals to receive a fair amount of consideration, but if we leave it too long, interest in the project might wane.  We don't want a situation where the basic feasibility analyses have been done for all the proposals and there's not much else to do until the vote is called, but there's still a month to go.  Do people think that two months would be about right?  More?  Less?

(rpulkrabek: I don't mean to completely ignore your post about Pugh matrices etc. by just posting this – I wrote this up offline and have just pasted it now.  I will reply to your post separately soon).

brmj said:

Let me say now that there were studies of this by Krafft Ehricke in the late 70s and early to mid 80s that looked rather promising, and at least one suitible landing site was identified, so this may not be as crazy as it first sounds.

Hey, that's great!  I had assumed this would turn out to be quite infeasible, at least without seriously violating simplicity, but if there's actually something to it then this could turn out to be an interesting proposal.

Possible basis for another CLLARE proposal: the LEAP "lunar ambulance".  Something like this perhaps pull off a balloon-cushioned skid landing?  The biggest challenge would be keeping an ascent engine intact during that landing.  Alternately, perhaps it could land softly, vertically upright?  Such a design would not be entirely unlike the Tycho Brahe.

The benefit of a skid landing would be significant savings in the delta-v required for landing, and hence in propellant mass.

It's admittedly quite unorthodox and may not be worth pursuing, but I'd at least like to see it considered.  Finding suitably obstacle-free landing sites should be quite easy with the sheer volume of high resolution photos of the surface one can access on the web these days.