RCS Mun Landing?

[Red Shirt]

I saw on pic in a thread a couple days ago that appeared to show a lander can with only a RCS tank and thrusters landed on what I thought was Mun. I tried it today and hit revert just before slamming into the Mun at 350 m/s. Can it be done? If so, how?

Edited September 25, 2015 by Red Shirt

[xtoro]

Minmus maybe, but for a Mun RCS landing, it would have to be quite a lightweight ship or probe, or have lots of thrusters. Where is the pic of this ship you saw?

[The_Rocketeer]

If you can get your Mun RCS TWR up over 1, sure it can be done. You might need a lot of thrusters tho.

[Kaezan]

It can be done but its less efficient than using LF+O Engines. Pick a 2.5m monoprop tank and add a bunch of "rcs anywhere" ports. use the rocket equation to figure out the values. You need at least 60 kN of Thrust.

[ForScience6686]

I don't think it would be recommended except for small probes. I have done it, even h had a small science hopper with only rcs, don't think it was worth it though but worked great at minimus.

[The_Rocketeer]

Very simple lander, 250 mono, 24 place-anywhere thrusters and 8 thruster blocks, gave me 20 seconds of burn, got me to about 150m/s in Kerbin atmo/gravity.

Edit: no the last shot isn't proof I was using infinite fuel, I was just freakishly accurate catching the 0.00 resource with the screenshot.

Javascript is disabled. View full album

Edited September 25, 2015 by The_Rocketeer

[Alshain]

I saw on pic in a thread a couple days ago that appeared to show a lander can with only a RCS tank and thrusters landed on what I thought was Mun. I tried it today and hit revert just before slamming into the Mun at 350 m/s. Can it be done? If so, how?

Are you sure it was RCS Thrusters and not O-10 monoprop engines? RCS thrusters with something as heavy as a lander can would be hard to do right, probably not impossible. O-10's on the other hand, absolutely possible. Do it all the time. The one in my signature (click for more pics) lands with LFO, but returns with nothing but monopropellant using O-10's, the RCS is just for docking.

Edited September 25, 2015 by Alshain

[Red Shirt]

I have no idea where I saw the lander but it look a lot like The_Rocketeer's pic. I thought it sounded a little too good to be true. I think this goes under myth busted.

[FlyingPete]

It's simple enough to build an all-monopropellant lander with the O-10 engines, so it should be possible with the RCS thrusters. Control may be more difficult though. In fact, with the built-in propellant tanks in the command pods, it can be more efficient for Minmus.

[Alshain]

It's simple enough to build an all-monopropellant lander with the O-10 engines, so it should be possible with the RCS thrusters. Control may be more difficult though. In fact, with the built-in propellant tanks in the command pods, it can be more efficient for Minmus.

The issue is not building one, it's slowing down in time for landing with them on the Mun. You have 1 kN of thrust, compared to 20 on the Puff. The ISP is about the same but you would need 40 RCS jets to be equivalent. Like I said, not impossible, but not something I'm doing anytime soon.

[GoSlash27]

Red Shirt (love the name BTW)

You probably saw my first Mun lander from back in the .18 demo.

Yes absolutely you can still do it using only RCS thrusters. All the parts stats and celestial body parameters are the same as they were back then.

It's not the most efficient way to do it now, but it was at the time.

Best,

-Slashy

- - - Updated - - -

All,

4 RCS quads would be adequate for a 1t payload on the Mun. No biggy, it's just not a very efficient way to go about it.

Best,

-Slashy

[Nothalogh]

Red Shirt (love the name BTW)

You probably saw my first Mun lander from back in the .18 demo.

http://i52.photobucket.com/albums/g13/GoSlash27/KSP/Lander1_zpsf1b814ca.jpg

Yes absolutely you can still do it using only RCS thrusters. All the parts stats and celestial body parameters are the same as they were back then.

It's not the most efficient way to do it now, but it was at the time.

Best,

-Slashy

- - - Updated - - -

All,

4 RCS quads would be adequate for a 1t payload on the Mun. No biggy, it's just not a very efficient way to go about it.

Best,

-Slashy

But where's the parachute?

[Kaezan]

But where's the parachute?

Aint nobody got time for that!

[GoSlash27]

But where's the parachute?

Nothalogh,

On the return vessel.

Like the Apollo, there was a separate CM module. Unlike the Apollo program, there was no docking capability in .18 demo. This meant 2 "Mercury" sized launches instead of 1 "Saturn" sized launch.

I did a munar orbit rendezvous and EVA to the CM for the trip home. Jeb made it home safely and had a tickertape parade, followed by my immediate purchase of .24 Beta.

Best,

-Slashy

[Nothalogh]

Nothalogh,

On the return vessel.

Like the Apollo, there was a separate CM module. Unlike the Apollo program, there was no docking capability in .18 demo. This meant 2 "Mercury" sized launches instead of 1 "Saturn" sized launch.

I did a munar orbit rendezvous and EVA to the CM for the trip home. Jeb made it home safely and had a tickertape parade, followed by my immediate purchase of .24 Beta.

Best,

-Slashy

Ah, I assumed you did helmet landing

[Red Shirt]

Well Slashy, your craft is not the one I saw, however I am inspired. I suppose it serves no purpose in 1.04, but I will land with RCS thrusters only! Pictures may follow... unless it ends badly, in which case pictures are pretty much guaranteed.

[Randazzo]

Already answered, nevermind.

Edited September 26, 2015 by Randazzo

[GoSlash27]

Well Slashy, your craft is not the one I saw, however I am inspired. I suppose it serves no purpose in 1.04, but I will land with RCS thrusters only! Pictures may follow... unless it ends badly, in which case pictures are pretty much guaranteed.

Red shirt,

I like your attitude!

Remember that you are operating in Munar gravity and vacuum, so you need far less engine and fuel than testing on Kerbin would suggest. We did it back then without the aid of mods as a matter of course. In fact, I planned my whole mission and designed the vehicles using nothing more than pen/ paper and a Pickett No. 120 sliderule.

It's just as feasible now as it was back then, so don't give up hope!

I look forward to seeing your mission report.

Best,

-Slashy

[Red Shirt]

So, apparently you can set a lander can safely on Mun using only RCS Thrusters. I used 8 multiport ones and I had my doubts until the last few meters.

The however of the mission is, I did not know how to calculate the amount of propellant required. The lander can started its ascent but at about 200 m/s it sputtered its last. Doing the only sensible thing, Bob quickly EVA'd and with some work achieved orbit. A rescue mission will follow. The tricky part of an EVA orbit is switching back and forth with map view to reorient Bob. He does not stay feet down automatically as he rotates making circularization a little harder.

[GoSlash27]

Red Shirt,

Back in my day we designed all of our landers to use RCS. We walked 20 miles uphill to school and back both ways and we were thankful for what we had!

Congratulations; you have rediscovered the lost art of RCS landers!

For calculation purposes...

the FL-R25 tank weighs 1/5 the mass of fuel it carries and the Isp of a thruster quad is 240 sec.

You can reverse the rocket equation thusly

http://forum.kerbalspaceprogram.com/threads/102809

and design RCS powered stages for landers or ascent stages for nearly all occasions.

We made use of these back then because we didn't have LF&O engines small enough to be suitable for the job. We have those now although occasionally the RCS lifter still winds up being the lightest option overall.

Use it in good health!

-Slashy

Edited September 27, 2015 by GoSlash27

[panzer1b]

Ive found that vernors make excellent engines for this (and even let some of my lighter ships VTOL in lighter gravity such as minmus).

Aside from that, with regular RCS engines (the 4 way block or the small nozzle one) its either gonna take ALOT of engines, or a very small craft.

[Red Shirt]

Red Shirt,

Back in my day we designed all of our landers to use RCS. We walked 20 miles uphill to school and back both ways and we were thankful for what we had!

https://deadhomersociety.files.wordpress.com/2012/10/treehouseofhorrorvi7.png

Congratulations; you have rediscovered the lost art of RCS landers!

For calculation purposes...

the FL-R25 tank weighs 1/5 the mass of fuel it carries and the Isp of a thruster quad is 240 sec.

You can reverse the rocket equation thusly

http://forum.kerbalspaceprogram.com/threads/102809

and design RCS powered stages for landers or ascent stages for nearly all occasions.

We made use of these back then because we didn't have LF&O engines small enough to be suitable for the job. We have those now although occasionally the RCS lifter still winds up being the lightest option overall.

Use it in good health!

-Slashy

Sorry I missed the "good ole days" in KSP. I would have been a survivor. It would take some time today to refresh but in high school we used a slide rule in chem class. In college I bought my first calculator - it cost $300 and did only the most basic calculations. Bought my first scientific calc later for my job. It cost $150. The old school guys laughed at me. They used a logarithm book when doing trig. Seriously, they could flip pages and add as fast as I could punch numbers into the calculator. Each generation has its own version of old school. It may not seem as glamorous but old school obviously works. The pyramids are still standing.

Oh, and update - rendezvoused an unmanned rescue ship with Bob floating 12k above the Mun and returned safely.