Manned Moho Landing

[The Jedi Master]

What the title says. Last time I tried it, this happened:

So, can someone please tell me how to send a manned mission to Moho, from construction to splashdown back on Kerbin? Much appreciated!

[automcdonough]

step 1: know your goal.

http://wiki.kerbalspaceprogram.com/wiki/Moho

This should give you an idea how much fuel to pack, and if your lander can use parachutes or will have to slow down with rockets. In this case, no chutes.

Also, heat will be an issue. I would suggest NOT using nuke engine for landing stage.

step 2: build a good ship, mission specific.

A one man lander can be much smaller than you have in your pic. A rocko tank with nuke engine for upper stage should get you there easily, detach it when it's landing time. Again, you won't have chutes to help land, and heat will be an issue so consider oversizing the engines somewhat. I like to use mechjeb or engineer mod to keep an eye on thrust/weight and d/v of fuel.

step 3: launch it

again, mechjeb is a great set of training wheels. Setting up orbital intercepts without use of that or protractor seems like black magic to me, but now that you can set up maneuvers there is a 'grind it till you find it' option.

[RawChicken]

Well in that picture the engine has exploded because you had too much weight ontop of it. Ships are not solid objects, the gae calculates all stresses along the ship and if a part has too much, it will explode.

Also, if you want to reduce mass, make a smaller lander.

Also, add docking ports and take the lander to orbit, and then send a "space tug" to push it to wherever you wanna go!

[Merinsan]

Also, heat will be an issue. I would suggest NOT using nuke engine for landing stage.

I'm fairly sure heat is no longer an issue with Moho. I recently landed there, throttling at full thrust with small engines and didn't get any overheating indication. I believe that when they removed the atmosphere the heating effects were also removed.

I've still not done a successful return though, it's a lot of work. To do it, you'll want an interplanetary stage that you leave in orbit while you land.

[RawChicken]

I have never had a nuke engie exploding because of heat in space, the red indicator goes 7/8 full and stops there.

[Finnerty]

Call me crazy, but looking at this picture I think your staging was wrong. It looks to me like your upper stage rockets fired first and just ripped away from your bottom stage. I don't see any of your lower stage rockets firing at all.

[The Jedi Master]

Call me crazy, but looking at this picture I think your staging was wrong. It looks to me like your upper stage rockets fired first and just ripped away from your bottom stage. I don't see any of your lower stage rockets firing at all.

It broke up as soon as physics kicked in.

[magnemoe]

Well in that picture the engine has exploded because you had too much weight ontop of it. Ships are not solid objects, the gae calculates all stresses along the ship and if a part has too much, it will explode.

Also, if you want to reduce mass, make a smaller lander.

Also, add docking ports and take the lander to orbit, and then send a "space tug" to push it to wherever you wanna go!

Yes more struts, you want to connect parts in long stages together. you also want some up to the lander on top.

Do you have an engine in center or is it just an drop tank?

One tips to make the lander easier to handle is to put small tanks in the gaps between the four large, then put the engines on them, pipe from center tank to small tank, and from side tanks to center.

This should not only let you connect landing legs on tanks but even let you drop the side tanks after takeoff, at least two of them.

[Ringer]

The problems I've had with Moho involve the orbital transfer. Its inclination SUCKS; calculating the circular orbit transfer gives you Sun periapsis/timing far off from Moho's actual position, so the adjustment costs about another thousand dV. Since I don't know how to calculate the transfer better, I've always had to do this.

There's a lot to be said for engineering a rocket's stages to have the right amount of thrust and dV, but I usually resort to the "more Rockomax" strategy. Since cost isn't an issue (yet), all that matters is being able to attach another stage that can accelerate up the one you already have for a little bit longer. So all that matters in that case is stability.

I'd use asparagus staging for the transfer stage. Nuke engine stack in the middle, and two pairs of nuke stacks radially attached around it. If you get that into Kerbin orbit, you should be able to make the transfer and use up one of the asparagus pairs, leaving you 3 engines and (hopefully fully) stacks to adjust your transfer and achieve orbit around Moho. The final, central stage should be sufficient for a landing (I'm talking a one-man pod here though). For getting those 5 engines and stacks into Kerbin orbit, 4 Rockomax (orange) tanks with Mainsail engines, and maybe some solid boosters, should be well sufficient.

[Ringer]

http://imgur.com/a/GwenY

Here's what I just described. Let's see if it launches...

Edit: The answer is yes, but it would cost at a good deal of fuel from my transfer stage to circularize the Kerbin orbit. Anyway, hope that gives you some ideas!

Edit again: I did that anyway, performed the most wasteful orbital transfer ever (probably 1-2k dV in adjustment burns), and realized I forget landing legs, but it worked! The ISP of those nuclear engines is such a blessing; a bunch of dV to spare, landed on Moho. CHECK IT

Edited May 11, 2013 by Ringer

[Spartwo]

have launch towers holding the upper half.the force from liftoff wont be enough to destroy your ship.

[Temstar]

Moho does have one thing going for it though - frequent transfer window and rapid transit time. Transfer windows for Moho opens up something like every 30 days and it can take as little as 25 days to reach. So one option for manned Moho landing is just to send tanker after tanker to Moho to build up a stockpile of fuel as well as a lander. Then once you're ready just send a ship to Moho with enough delta-V (say 7000m/s) to get into Moho orbit and then reach the Moho propellant depot. Then you can transfer the crew over to the lander for the landing, then get back to the depot refuel the ship they used to reach Moho and head back to Kerbin.

I did something similar with my Moho rover mission:

So I went the rover/lander towards Moho and like a lot of us here in this thread I underestimated the amount of delta-V required to reach Moho. I used up all of my fuel and managed to get into a 50km x 180km elliptical near-polar orbit.

So with my lander stuck in Moho orbit I decided to launch a refuel mission to Moho to salvage the situation:

Upon reaching Moho I had a difference in orbit of the two craft by something like 100 degrees, so another big burn in the order of 500m/s delta-V was required to align the orbits.

Upon docking I was able to deliver about 822L of bipropellent to the lander. 822L out of the original 4800L delivered, so 5/6 of the fuel was spent just to get that last 1/6 to Moho.

After refuelling I undocked the tanker and set it to crash into Moho with the remaining RCS fuel. Then I managed to land the lander on Moho and release the rover.

So manned mission to Moho could use a similar structure. Except instead of going first you send tankers to Moho first to build up the stockpile of fuel there 800L at a time. Only once there is enough fuel at Moho do you then send the manned craft.

[magnemoe]

The problems I've had with Moho involve the orbital transfer. Its inclination SUCKS; calculating the circular orbit transfer gives you Sun periapsis/timing far off from Moho's actual position, so the adjustment costs about another thousand dV. Since I don't know how to calculate the transfer better, I've always had to do this.

There's a lot to be said for engineering a rocket's stages to have the right amount of thrust and dV, but I usually resort to the "more Rockomax" strategy. Since cost isn't an issue (yet), all that matters is being able to attach another stage that can accelerate up the one you already have for a little bit longer. So all that matters in that case is stability.

I'd use asparagus staging for the transfer stage. Nuke engine stack in the middle, and two pairs of nuke stacks radially attached around it. If you get that into Kerbin orbit, you should be able to make the transfer and use up one of the asparagus pairs, leaving you 3 engines and (hopefully fully) stacks to adjust your transfer and achieve orbit around Moho. The final, central stage should be sufficient for a landing (I'm talking a one-man pod here though). For getting those 5 engines and stacks into Kerbin orbit, 4 Rockomax (orange) tanks with Mainsail engines, and maybe some solid boosters, should be well sufficient.

Did an fast test of this as I might return to Moho, my first mission was an massive 8000m/s mothership and an huge kertane miner, was on an grand tour so I went from Gilly to Moho then directly to Duna, yes I had very little fuel left, would had returned to Gilly had I not found an set of nodes who took me to Duna.

Using the 3 man pod an ship with 5 720 liter tanks had over 8000m/s, nuclear engines on 4 90 liter tanks between and the 4 external ones who was a bit below the center tank. This let me use standard landing legs. fuel lines from the four side tanks to the center and the side tanks could be dropped two and two after takeoff.

In addition I added an 720 drop tank below the central tank. with fuel lines to the outer tanks.

Used 1+4 asparagus orange+large gray in center, added an medium gray tank on top of boosters. Now one feature I used here was to add fuel line from center orange tank to the upper drop tank, I did also put an seperator between the orange and large gray tank with mainsail on the center stage.

Fired the nuclear engines at 1500m where their twr is better than mainsails. the boosters was between the nuclear engines so no problems here.

At the end of the gravity turn I turned off the last mainsail, moved the rest fuel to the orange tank and decoupled this. I was left with 12000 m/s. who is a bit of an overkill.

Return from Moho is far cheaper as you can aerobrake.

[creator1629]

i have a question, once you are in mohos orbit, how much delta v does it take to get back into kerbins orbit. i have around 2200 m/s of delta v left and im wondering if i can make a go of it or if i should send a refueling tanker