Lunar lander concept diagram | Lunar lander design | Forum

I have been thinking lately about how to extend our current plans for the lander frame to the complete vehicle.  This involves finding somewhere to put avionics etc., an RCS solution and some means of docking the lander with the fuel module.  Below is a concept diagram of one way we could perhaps put all this together – but I'm not that fond of it and I suspect somebody could come up with something better.

So, let's see what we have:

• Instead of the lander legs meeting at  pointed apex as per current renderings, they terminate a bit earlier in a square shape, which is easier to attach stuff to.
• Electronics etc. are arranged around the chair in a horseshoe shape.
• There is a cross-shaped structure underneath the chair/electronics which holds RCS units away from the seat.  The RCS units in this diagram are scaled down versions of the CM's RCS, which is probably suboptimal – originally I envisioned them as being exact copies of the CM RCS but then I realised they were probably far too big.  Rather than change the diagram I "scaled down", we should probably consider alternatives.
• Also at the ends of the cross-shaped structure are very strong (titanium?) vertical poles with some sort of attachment mechanism on the ends (perhaps combining magnets and some kind of simple locking structure) which allow the whole thing to attach to the end of the mission stack without blocking access to the chair.
• Two of these vertical poles have fuel lines integrated with them somehow (one for fuel, one for oxidiser).  The others may have anteannas in/on them.

Note that this diagram is quite poor in a few ways: the chair is shown point 45 degrees away from the nearest legs, but of course the steps are built onto one of the legs so the chair (and the horseshoe electronics structure around it) should be rotated 45 degrees from how they are shown in this diagram.  Note that the cross structure with the RCS should not be rotated as this would have the RCS units directly over the legs, and we don't want to melt our legs off during descent.  This diagram, at least in the top view, shows the RCS units directly over the tanks – obviously the arms they are on should be long enough that they are a safe distance away.  The problem with this is that the docking pylons may be too far apart to attach to the back of the stack without some kind of expanding adaptor – although that isn't a huge problem.

As I've said, I'm not too fond of this diagram, but it's the only thing that has been proposed so far.  Feel free to tear it to shreds or offer suggestions for improvement.

Good work in seeking out an appropriate forum and making a request – unfortunately it looks like we've received a disappointing response from a group of fairly dim individuals who obviously made no effort to read any of the material you linked them to.  There seems to be an idea on there that the fuel tanks are actually balloons, which means either that poster has no idea how balloons float (and hence doesn't realise that this won't work in space) or that they think we have no idea how balloons float.

I suppose this is raises an important issue, though, which is that we are going to have to learn how to manage the all important concept of take-serious-ability for our first introductions to people/groups.  I think there are two facets to this: making ourselves look serious and respectable, and also combatting the public perception that our sorts of endeavours are impossible.  I have read John Carmack quoted somewhere as saying "Rocket science has been mythologised out of all proportion to its actual difficulty", and I think this is true of space travel in general.  There is a public perception that things need to be almost magical to work in space – you can't just take mundane metals and weld them together, you need secret NASA pixie dust!  I've suffered a little from this issue myself, not in thinking that our task was impossible but in being constantly surprised while working on it at how not-impossible it is.  To be sure, space travel is hard, but it's not magic.  We need to think of a way to break through the misconception that this can't possibly work and make people realise that building a simple spaceship in a home workshop is only a medium step further than building a simple airplane or a simple submarine in a home workshop – and people do those all the time.

I wonder if we should give the effort to build a lander frame and put a simple cold gas RCS on it should be given some sort of official "subproject" status, with its own Wiki page, to assist in soliciting interest?  There we could explain exactly what we are trying to do and why we are trying to do it.  We could have a separate ChipIn (or similar) campaign running to raise money purely for this subproject.

The goals of the subproject would be:

• To get better estimates of lander frame mass and cost.
• To test strength/stability of the lander frame by loading it with something of roughly the same size and mass of our intended use and dropping it onto a roughly lunar surface from various heights and at various angles.
• To see what sort of rotational / stabilisation performance we can achieve with nitrogen or CO2 cold gas thrusters by actually putting some on a lander that is approximately the correct size/shape/mass.  I would really love to use this sort of system instead of actual chemical rockets for our RCS (aside: RCS stands for reaction control system, not rocket control system) if it is feasible, and this seems like the easiest way to test.
• To generate awesome propaganda photos/videos by putting the lander somewhere remote and roughly lunar-looking.

Can anybody think of any other potential goals?

The subproject description page should emphasise that this is not the lander that will go to the moon – nor is it even a test model of the exact design of lander that will go to the moon.  It is something cheap and simple that is roughly what will go to the moon – our actual design will probably be refined considerably based on the 100 little things we will learn from building this mockup, trying to spin it around with cold gas RCS and getting someone in a mock moonsuit to climb up and down it a few times in the desert.  When it comes to things like designing seat suspension later on, this frame will provide a decent test bed to bolt prototypes onto for testing.