Crude Render of Lunar Lander Frame | Lunar lander design | Forum

Crude Render of Lunar Lander Frame

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11:44 am
November 22, 2009

Rocket-To-The-Moon

Grand Forks, North Dakota, USA

Member

posts 279

Post edited 12:29 pm – November 22, 2009 by Rocket-To-The-Moon

Here is a crude render of the lander frame. This is definitely not an engineering drawing, more of a proof of concept.

In this drawing the lander legs are in their stowed position. Also the legs do not have their foot pads attached. I'll see if I can get the legs rotated around and then make another render.

I think that the material I have chosen is too large for the job. It is extruded aluminum box section with a wall thickness of 3.175mm so it looks a lot heavier than it actually is. The main frame beams have a mass of 2.519 kg/meter and the frame is 2m square (ignoring the leg rotators and buffer springs). This means that the entire frame is about 40kg (minus the legs). There are still beams that need to be put in the lower portion of the frame which will increase the mass further.

On vacation through December 30, my participation will be lacking until after then. | Main Workgroups: Propulsion (Booster) & Spacecraft Engineering (Lander)

12:17 pm
November 22, 2009

Rocket-To-The-Moon

Grand Forks, North Dakota, USA

Member

posts 279

Post edited 1:14 pm – November 22, 2009 by Rocket-To-The-Moon

Here is a second version that uses smaller material.

It may be better if the legs somehow fold underneath of the lander or if the buffer spring is attached to the leg so that it doesn't stick out so far. I keep forgetting to add parts of the structure (vertical member and lower trusses). I'll have another render in a few hours with those components in place.

On vacation through December 30, my participation will be lacking until after then. | Main Workgroups: Propulsion (Booster) & Spacecraft Engineering (Lander)

1:15 pm
November 22, 2009

Rocket-To-The-Moon

Grand Forks, North Dakota, USA

Member

posts 279

Now we're getting somewhere. Here is version 3:

On vacation through December 30, my participation will be lacking until after then. | Main Workgroups: Propulsion (Booster) & Spacecraft Engineering (Lander)

2:16 pm
November 22, 2009

Rocket-To-The-Moon

Grand Forks, North Dakota, USA

Member

posts 279

Post edited 2:18 pm – November 22, 2009 by Rocket-To-The-Moon

Now it is starting to look like something. I just need to add the foot pads, seat, and ladder rungs. Just by eyeball it looks like it has a pretty impressive propellant mass fraction.

On vacation through December 30, my participation will be lacking until after then. | Main Workgroups: Propulsion (Booster) & Spacecraft Engineering (Lander)

2:18 pm
November 22, 2009

Rocket-To-The-Moon

Grand Forks, North Dakota, USA

Member

posts 279

On vacation through December 30, my participation will be lacking until after then. | Main Workgroups: Propulsion (Booster) & Spacecraft Engineering (Lander)

2:52 pm
November 22, 2009

Rocket-To-The-Moon

Grand Forks, North Dakota, USA

Member

posts 279

Post edited 2:54 pm – November 22, 2009 by Rocket-To-The-Moon

We have feet now. The struts on the feet are designed to be one of the primary shock absorbers (along with the buffer springs). To simplify things, the struts simply use friction between them and the strut collar (the part that connects to the leg) to absorb the impact. It is a one time system, once it is compressed it will not spring back by itself.

On vacation through December 30, my participation will be lacking until after then. | Main Workgroups: Propulsion (Booster) & Spacecraft Engineering (Lander)

4:36 pm
November 22, 2009

Rocket-To-The-Moon

Grand Forks, North Dakota, USA

Member

posts 279

Post edited 4:50 pm – November 22, 2009 by Rocket-To-The-Moon

I think that I'm almost done with the lander concept. As you can see there is quite a bit of empty space for anciliary equipment such as electronics, oxygen, and communications equipment. I'm looking for feedback to see what you think.

In the second image you can see what the lander looks like in its launch configuration with the legs folded.

On vacation through December 30, my participation will be lacking until after then. | Main Workgroups: Propulsion (Booster) & Spacecraft Engineering (Lander)

5:33 pm
November 22, 2009

Rocket-To-The-Moon

Grand Forks, North Dakota, USA

Member

posts 279

I have updated the Wiki's lander page.

On vacation through December 30, my participation will be lacking until after then. | Main Workgroups: Propulsion (Booster) & Spacecraft Engineering (Lander)

5:34 pm
November 22, 2009

Rocket-To-The-Moon

Grand Forks, North Dakota, USA

Member

posts 279

On vacation through December 30, my participation will be lacking until after then. | Main Workgroups: Propulsion (Booster) & Spacecraft Engineering (Lander)

8:55 pm
November 22, 2009

Luke Maurits

Adelaide, Australia

Admin

posts 485

You have done some fantastic work here, Rocket. Congratulations and thank you.

Our lander at this stage reminds me a little of Armadillo Aerospace's "Pixel" vehicle (which has done well in the Northrup Grumann Lunar Lander Challenge.

I think it is great that you have specified actual materials and dimensions. Now we can pose questions to structural engineers, although I'm not quite sure what we'd want to ask because that's not my field.

A few questions I have: how easy is it to walk down stairs in a full EVA-worthy spacesuit in 1/6g without hand rails on your first try? And was the size of the fuel tanks a principled estimate? Can we figure out how much those tanks would hold of likely fuels and oxiidisers and see how long those quantities would last in an existing engine?

We should probably start to think about what sort of electronics etc. will be necessary for the lander, what sort of access to them the astronaut will require and whereabouts they can be placed to meet those needs.

Main workgroups: Mission Planning, Navigation and Guidance. I do maths, physics, C, Python and Java. Scaling back involvement to sanity-compatible levels on Jan 01 2010.

9:27 pm
November 22, 2009

Rocket-To-The-Moon

Grand Forks, North Dakota, USA

Member

posts 279

Post edited 9:28 pm – November 22, 2009 by Rocket-To-The-Moon

Thanks, it was a nice way to spend my Sunday afternoon.

I've been going through videos and information on some of the Lander Challenge vehicles to get an idea of what we are working with. With so many teams building these vehicles it shows that it is definitely possible to do on a small budget.

The issue of the ladder is definitely something that I have thought about. I assume that we will have simple handrails (maybe just tensioned cables to save weight) that run along the propellant tanks. To be honest, it is difficult to work with spherical and cylindrical shapes in SketchUp so I didn't bother.

The size of the fuel tanks is essentially based on the biggest tanks that I could fit in the space provided. If they get any larger you have to move them out from the vehicle center line. This isn't necessarily bad though, because as it is the buffer springs extend well past the edge of the vehicle. My solution to this problem may be to attach the buffer springs to the legs themselves and then allow them to swing with the leg until it contacts the leg rotator main frame.

I'll measure the outside diameter of the tanks tomorrow and calculate how much they can hold. I'm not sure what ratio the hypergolic fuel that we will be using is mixed in. If it is 1:1 then we are golden, but if it is something like 3.6:1 then the tanks will have to be re sized and rearranged. The Texel lander looks like its tanks are all the same size so that gives me a good feeling.

Not a finished product, but I hope that it can be used to help draw attention to the project.

On vacation through December 30, my participation will be lacking until after then. | Main Workgroups: Propulsion (Booster) & Spacecraft Engineering (Lander)

9:41 pm
November 22, 2009

Luke Maurits

Adelaide, Australia

Admin

posts 485

Rocket-To-The-Moon said:

To be honest, it is difficult to work with spherical and cylindrical shapes in SketchUp so I didn't bother.

You're telling me! The other day I tried to do simple, concept models of the CM and SM, just so their Wiki pages were not so blank. I promptly assumed I was missing something because it was so hard and gave up. You certainly seem to know what you are doing with it, though.

Main workgroups: Mission Planning, Navigation and Guidance. I do maths, physics, C, Python and Java. Scaling back involvement to sanity-compatible levels on Jan 01 2010.

9:48 pm
November 22, 2009

Rocket-To-The-Moon

Grand Forks, North Dakota, USA

Member

posts 279

Post edited 9:49 pm – November 22, 2009 by Rocket-To-The-Moon

I just learned to use it by tinkering around (really, really wanting to make the end product was my carrot on a stick). It is amazing how fast you can learn when it is something that you are truly interested in doing. I may try to make a CM and SM later this week. At the moment my objective is attracting new members and I figure that not too many people would randomly find the forum and read hundreds of posts. Hopefully these little pieces of eye candy will help to bring our vision to life.

On vacation through December 30, my participation will be lacking until after then. | Main Workgroups: Propulsion (Booster) & Spacecraft Engineering (Lander)

10:02 pm
November 22, 2009

Luke Maurits

Adelaide, Australia

Admin

posts 485

I think this is a wise approach. Now that we have both booster and lander models, SM and CM are the only things missing before we could in principle provide rough videos outlining the entire mission.

Main workgroups: Mission Planning, Navigation and Guidance. I do maths, physics, C, Python and Java. Scaling back involvement to sanity-compatible levels on Jan 01 2010.

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