Mun Rover Questions

[helgeras]

Hi,

I am trying to get a rover to the moon, and I have a few questions:

- I am using a Mk2 Lander Can. However, it is oriented vertically, so when I man the rover, the Navball is not oriented correctly. How can I fix this?

- I built the rover first, then added a lander module on top of it. The idea is that this lander module will be used to get Jeb back home after the mission, so first it drops the rover from very low altitude, then it lands next to it. However, the lander can (i.e. the rower) is where the kerbals are placed by default. Won't this mean that I will control the rover and not the lander when I separate them in low altitude? That won't be good as I have to fly the lander, how can I fix this?

- My entire rocket is way too expensive, it costs nearly 200 k! It is way overpowered, but on my first try to get a rover to the Mun I ran out of fuel so low that the rover landed ok and the lander fell over because I ran out of fuel.

Can anyone suggest a much cheeper design that gives me a rover plus support that can bring the rover to the mun and the kerbal back home again?

Edited August 1, 2014 by helgeras

[DannySwish]

1. You could add a small probe core in the correct orientation on the rover and either make that the parent part, or manually right-click it once in-flight and select "Control from here."

2. You can move kerbals around and place them wherever you wish before launching by selecting the third blue tab at the top (next to the one for action groups). Be aware that due to a bug, the positions you set might reset if you go off to do something else afterwards. Only swap them around once you're ready to hit the launch button. (This bug might've been fixed in the .24 update, I haven't checked.)

3. It'd probably be easier if you were to include the craft file so we could tell you how to make your ship more efficient/cost effective.

[Callmedave]

A probe core or even a docking port in the correct place will allow you a new 'control' form here' for the correct orientation.

As mentioned above you can move Kerbals around in the VAB/SPH but the bug is still there so do this last thing before launch.

Can you make rocket so that the lander lands with the rover still attached, once landed the rover detaches itself?

Legs on beams can give you a good amount of clearance under the lander, or a rover with a little RCS on top of the lander can easily 'lift' itself off.

[helgeras]

Thanks for the answers. I placed a docking port on the rover and it did the trick. I have gotten the price down to 150 k, isn't that still a bit expensive?

Here's a picture of the rocket, and a craft file:

https://dl.dropboxusercontent.com/u/7714699/Mun%20Rover.JPG

https://dl.dropboxusercontent.com/u/7714699/Mun%20Rover.craft

oh, and a picture I took of the galaxies M81 and M82 with my telescope. Not that it is relevant for the discussion, but I had it in my dropbox and I am just proud of it

https://dl.dropboxusercontent.com/u/7714699/M81_82_20140420%20Try%204.jpg

Anyway, what is a reasonable price for a rover to the Mun?

[Geschosskopf]

Can anyone suggest a much cheeper design that gives me a rover plus support that can bring the rover to the mun and the kerbal back home again?

Well, the obvious answer is to make a much smaller rover. I mean, roving any distance on Mun is an exercise in futility and frustration. It's just not a very practical way of traveling any more than a few clicks due to the craters. Craters eat rovers. You can try to avoid them but this will entail long hours of your real life time making extensive detours, and eventually you'll fall into one anyway and wreck far from your ship. Mun is littered with thousands of big, fancy rovers that their designers sent there with high hopes and much fanfare, only to abandon and/or wreck them after quickly realizing their uselessness.

So abandon dreams of going to multiple biomes overland. Move the lander instead. If you just want 1 Kerbal to be able to move around some within 2-3km of the lander, like say to visit an arch on a nearby hill, then just fly him there with his jetpack. If you want to move multiple Kerbals at the same time over the same distance, then a very small, simple rover suffices. For instance, you can take one of the 2m square panels, put one of the smallest wheels on each corner, give it a small probe core, a headlight, and 2 RTGs, and then slap on as many lawn chairs as you want. MUCH lighter and cheaper than the big rover you've got here, and just as useful.

[Wanderfound]

Thanks for the answers. I placed a docking port on the rover and it did the trick. I have gotten the price down to 150 k, isn't that still a bit expensive?

Somewhat.

If you want to shave the cost down, lose the asparagus liquid booster and use a big all-solid fuel first stage (as in strap your circularisation/transfer rocket on top of a lot of solids, don't just put some around the outside). Use only one decoupler as the joint between the solid and liquid stages; reinforce with struts to compensate for the weak connection.

Space the boosters out with girders [1] so that they don't overheat, and then strut the whole thing to hell and back. The tall solid boosters are best for this, but you can do it with a few stages worth of trashcans if you have to. Tweak the thrust limiter in order to keep the TWR below two (make sure all boosters are at the same setting so they all run out of fuel simultaneously), and aim to have the solids run out just before your apoapsis hits 70km. Circularise with a high-efficiency liquid engine, and use the same engine for Munar insertion and capture.

Liquid engines and decouplers are expensive. Solid boosters, struts and girders are cheap.

[1] As in, start with one booster, then attach a girder oriented radially about halfway up. Attach another booster to that. Then take off the girder and reattach it and the attached booster to the first booster, but this time with four or six times symmetry turned on. Clone the girder/booster and repeat, building rings outwards until you've got the power you want when you fire 'em all at once. Run struts from the top of each booster to the bottom of its neighbours, building a collection of X-shaped reinforcements.

[Wanderfound]

Nice galaxies, BTW.

[Torquemadus]

My entire rocket is way too expensive, it costs nearly 200 k! Can anyone suggest a much cheeper design that gives me a rover plus support that can bring the rover to the mun and the kerbal back home again?

Solid rockets are cheap. Really cheap. They really are "trash bins full of boom".

Take a look at how much different solid rockets and liquid fuel tanks and engines cost in the VAB. You can use tweakables to remove the fuel from fuel tanks and solid rockets to see how much they are worth when empty. Most of the cost of a liquid fuelled rocket comes from the tanks and engines, not the fuel. This gives players a good incentive to build re-useable vehicles that recover the engines and empty tanks.

Solid rockets are worth a pittance once empty. This makes them ideal for a disposable first stage.

I like to make my upper stages re-useable, but I prefer solids for my first stage.

[helgeras]

Omg, I flew my Rover to the moon and landed, and THEN I noticed that I Lomy Kerman had climbed into the Rover right before takeoff not knowing that there wasn't space for 2 on the return trip LOL.

Oh well, I guess I will have to mount a rescue flight to save him.

I know that you warned me about the bug about Kermans, but I fell for it anyway ... Sneaky little green *###&

[nremies1]

So abandon dreams of going to multiple biomes overland. Move the lander instead.

Tried exactly this plan the other day - I'll just land here, collect science, driver over there and collect more! Terrible idea. Had to figure out how to carry the thing there in the first place, then get it down on the ground safely, then try driving carefully to a different biome. Wrecked it after an hour of driving.

Time to toss the rover in the "failed ideas" pile behind KSC and just lander-hop instead.