Project Roskosmos "тайга" Lunar Lander

[N_Molson]

Electro-motors are around 70% effective.

Thanks, I had doubts about this point. So the cooling pump will convert 30% of it's input in heat !

Edit : I assumed that an electrical heater should have an efficiency of 100%, as long as it doesn't produce sound or light ?

---------- Post added at 12:48 PM ---------- Previous post was at 12:28 AM ----------

I added a shutter to the front window, that will also act as a visor. This was obviously needed for thermal control (also, it's not convenient to have the Sun in the eyes during the final landing phase !).

It will be animated ; maybe the window shape is going to change a little bit, a rectangle isn't very convenient for various reasons. An electrical motor will allow various positions.

Also notice the "toolboxes" (unpressurized) attached to the lander chassis. Here will be stored the stuff that is going to be used on the lunar surface. Maybe a few spare tools for possible repairs also...

 

[Urwumpe]

If you plan possible repairs, maybe you should then also put a small walkable perimeter on top of the tank, so the important ascent module systems can be reached.

Starts to look already very realistic, only the shape of the lower structure and how it connects to the tank is lacking something, it doesn't look very stable, rather like the tank is just laying loose on top of the structure.

 

[N_Molson]

Starts to look already very realistic, only the shape of the lower structure and how it connects to the tank is lacking something, it doesn't look very stable, rather like the tank is just laying loose on top of the structure.

Thornton, which had an alpha version, made exactly the same statement. So I'm going to put some more work on this area.

And yes, some handles for EVAs would be useful too (even in a non-contingency situation ; we can imagine a LM-test LEO mission with an EVA planned to check the suits and the compression / decompression system.

 

[Urwumpe]

I would maybe do a hexagonal platform around the ascent stage (just concentric hexagons as main structure), that would be large enough for stepping on, even in space suit boots. But you should then also have a few rails around the ascent stage there, that permit securing the astronaut. The platform wouldn't be really high, but in a space suit, even just stumbling over a rock is a deadly risk.

For the camera and the astronaut ladder, there could be some gaps in the platform.

Another details: do you have the pressurant tanks inside the torus tank or outside? If you have them outside, there is a chance that they are visible. Pressurants are important for forcing the propellants to the engine, even for pump-fed engines, you need some pressure to prevent cavitation.

 

[N_Molson]

There are pressurant tanks next to the nozzle, you can't see them here. Though I'm not sure of their volume and how much He or N2 they should hold.

I have to keep the chassis very simple however ; that design was primarily imagined to save as much mass as possible. I'll add structural reinforcement between the tank and the chassis, though.

The key of that design is that the cabin ISN'T sitting on the torus tank. It's sitting on the internal tank, which is sitting on the chassis. There should be no contact between the torus tank and the cabin (making the separation easier). I'll try to post a pic without the torus, it will be easier to see.

Here it is, the torus tank is transparent on this pic.

Sidenote : I have to think to make the visor/shutter inside matte black (we don't want to blind the pilot with lunar reverberation !).

---------- Post added 05-04-11 at 03:10 PM ---------- Previous post was 05-03-11 at 06:30 PM ----------

The passive thermal control now works. It's a little rough around the corners but it's credible. If you point the spacecraft 90° away from the Sun, half of its surface is illuminated and the other half is in shadow, you get a thermal equilibrium.

Now, if you point the spacecraft towards the sun (0°), only the top (or the bottom) of the cabin is exposed, while the sides are in shadow, radiating heat away. It's the best attitude to help the spacecraft to cool down.

I assumed that 2% of the solar energy flux gets in and out of the cabin, because no insulation can be perfect. It's enough to greatly modify the stress you put on the cooling system.

There is room for improvement (the formula I use ignores the descent stage for now), but well, the idea works ! :jj:

Here's the demonstration : the top of the cabin receives heat from the Sun, the sides and the bottom are in shadow. Notice that the torus shape of the ext. tank should make it very efficient at dissipating the incoming heat flux.

- Shutter animation works !

 

[Urwumpe]

Ok, but I think you should have some things different then anyway:

Currently, your structure will react very badly on uneven landing loads - if you land on a slope, it will have strong torsion forces, even with impact dampers. You should always try to have only compression/decompression forces in a structure. even if you would use materials with high tensile strength, it would mean likely a higher mass as a structure that guided the forces better to the (simpler) ascent stage structure.

Next, you should include guide rails on the inside to ensure the stages do not impact on each other, especially if you do an emergency separation during higher rotation speeds.

Also, I feel like the pressurant spheres are too small, at least for the larger torus tank. For the ascent stage, they could be enough. But you also need volume for operating pneumatic valves and purging the engine between burns. And you will likely have pneumatic valves somewhere in the engine, because electric valves for high volume flows and high pressures are really heavy compared to a pneumatic valve that has just a small electric valve to control the pressure to it.

 

[N_Molson]

Yes, that sounds right.

The number of burns will be limited (between 4 - 6 ?). Orbital manoeuvers will be conducted through the RCS system.

 

[Urwumpe]

Yes, that sounds right.

The number of burns will be limited (between 4 - 6 ?). Orbital manoeuvers will be conducted through the RCS system.

Also include a pre-launch purge of the engine with high gas mass flow for removing dust from the inside of the nozzle. Apollo did not need this because their ascent engine was well protected inside, but you should see the same corrosive impingement by dust as the Apollo Descent Engine saw.

 

[N_Molson]

You gave me an idea

---------- Post added at 07:34 PM ---------- Previous post was at 06:47 PM ----------

That "nozzle cage" could protect the nozzle from a misplaced rock during the landing. It's not like you have a spare one, the nozzle integrity is the ticket to orbit !

 

[Grover]

you made that cage in that short time? thats quite impressive i must say

 

[Urwumpe]

Not a bad idea, maybe it would be better if you would already attach the landing gear at this structure as well, so the loads a spread better along the rigid part of the structure.

Anyway, any rock that is large enough for damaging the nozzle during landing would be large enough to be seen from far away. The small debris is worse, right after shutdown, you can literally shoot the dust and small stones into the engine nozzle by rebound.

 

[Grover]

maybe a cleaning could be done during the EVA, assisted by the on board space dyson

 

[N_Molson]

Not a bad idea, maybe it would be better if you would already attach the landing gear at this structure as well, so the loads a spread better along the rigid part of the structure.

I get what you mean, but that would involve a redesign. Not for the first release, but I keep this for later. The difficult part will be to avoid elevating the CoG too much, but that should be possible. A reserve engine (like in the LK) would be welcome, too

 

[Tycho]

Checking in for the first time in a while, I found this thread. This project looks exciting and can't wait to fly it! Thanks for all of your hard work, N_Molson! :thumbup:

 

[N_Molson]

Let's write a "little" to-do list (in fact, it is rather scary, so I begin to put priorities to keep my heading !) ;

* Defining shadow cones for Earth & Moon -> Beta
* Earth re-entry effects -> Beta
* Crew management system -> 50% done, Beta
* Engine advanced parameters (hi-pressure gas cleaning, ullage burns, limited restarts, pressurant management). -> Beta
* Modeling of an accurate docking target -> Beta
* LEVA simulation (using DanSteph UGCO "Action area" concept) -> v1.0
* Cabin pressure equalization when docked to the SoyuzTMA -> v1.0
* Moderate damage on rough landing -> Beta
* Systems failures -> v1.0
* Hatch (lock, manometer, handle) animation -> 25% done, Beta
* Guidance rails inside the descent stage for lunar liftoff -> Beta - DONE
* Descent AutoPilot -> v1.x
* Ascent AutoPilot -> v1.x
* Spacecraft remote guidance simulation in "unmanned mode" (delays...) -> v1.0
* Resizing of the toolboxes, animation of the doors, handles, tools -> v1.0
* Meshing of subsystems access panels for EVA repairs. ->v1.x
* Subsystems EVA repairs -> v1.x
* Sounds -> v1.0
* Load/Save of the variables -> Beta - In progress
* Re-design of the descent stage -> v2.0
* Add lunar dust ParticleStreams at very low altitudes -> Beta

... to be continued ! :blahblah:

 

[Grover]

earth re-entry? this thing will return to earth after Lunar landing? or is this a contingency for apollo 13 style emergency scenarios?

or is it just so it looks pretty when you burn it to pieces after aborted takeoff?

 

[N_Molson]

or is it just so it looks pretty when you burn it to pieces after aborted takeoff?

You got it ! :lol:

Also, there will be LEO LM Test scenarios, a la Apollo 9.

 

[Grover]

so in the case of an Apollo 13 scenario, you will be able to see it fry on a parabiloc direct-re-entry!

i suppose its worth a shot: Apollo 13: Europe's turn

 

[N_Molson]

Yes, if you successfully insert in Lunar Orbit and the tug that is supposed to wait you here for the return has a problem or is far off-plane, using the LM engine would be an alternative. Just check everything is ok BEFORE using the LM :lol:

 

[Grover]

what about fuel, is there a way to get the tug/soyuz fuel into the Lunar Module? otherwise youve got all your fuel in an unusable rocket, and no way home :S