Interplanetary Practice Runs

[grynspan]

In preparation for 0.17 and the new worlds to explore, I submit this plan for an interplanetary practice run, adapted from my own practice runs.

Note: These runs do not involve landing on the surface of any planet. They are akin to the real-life Apollos 8 and 10 missions, where the command modules (etc.) orbited the Moon but did not attempt to land. There are a few other practice runs posted here that involve landing on Kerbin in place of another planet.

Use of the fuel bug is not allowed. Do not run your engines at less than 66% of their maximum power. Do not run your engines at less than 80% of maximum power for more than ten minutes total time. (Running at 0% is not limited as it provides no fuel-bug advantage.) If attempting this challenge on 0.17 or later, disregard these instructions as the fuel bug is only present in 0.16.

Use good judgement and avoid mods that allow you an unfair advantage.

1) Build a rocket able to get into LKO and return with a parachute--minimal bells and whistles. This is your Kerbin Reentry Module, or KeRM.

2) Build a rocket able to escape Kerbin's gravity and enter a solar orbit. This is your Interplanetary Excursion Module, or IEM.

a) The IEM should not have the capacity for safe return to the surface of Kerbin (i.e. no parachutes/landing gear/legs and no attempts to land it on Kerbin after liftoff.)

The final stage (containing the command module) should not be decoupled from the final engine stage--they are one and the same.

c) Overall, your should be designed/equipped with long missions in mind. Several fuel tanks in the final stage are recommended (but optional.)

d) The KeRM should have enough crew slots to accomodate the crew of the IEM, and the IEM should carry at least 2 passengers (mod parts that add extra seating are allowed.)

3) Launch the KeRM and optionally get it into an orbit with as little eccentricity and inclination as possible (this will make it easier to reach it later.) Any reasonable orbital maneuvers are allowed, but you must have enough fuel to deorbit later on.

4) Once the KeRM's orbit is satisfactory, its crew should abandon ship by any means necessary. This includes:

a) reentering the atmosphere and plunging to their deaths;

being rescued by a third rocket;

c) EVAing and ending the mission; or

d) simply EVAing and suffocating in the vacuum of space.

Nothing's too good for our boys!

5) Launch the IEM and escape Kerbin's gravity. Put yourself into a keliocentric orbit that differs from Kerbin's by at least 1Gm. Have fun up there. Perform zero-gravity experiments and EVAs. Try a sundive. Pretend you're actually travelling to another planet. Whatever. Make sure you're up there for at least 200 days--the longer the trip, the better.

6) Return the IEM to Kerbin's sphere of influence and enter orbit around Kerbin. Be careful--if your orbit upon return is retrograde relative to the orbit of the KeRM, you will need to correct it before circularizing or you'll most certainly run out of fuel. Of course, you could try it the other way around, it's just not recommended.

7) Rendezvous with the KeRM and transfer your crew to it. Wave goodbye to the IEM. You did bring your goodbye-waving kerchief, didn't you?

8) Deorbit and safely return to the surface of Kerbin.

a) Extra points the closer you land to the launch pad.

If at any point during your return your crew experiences more than 8Gs, assume they were converted to a delicious creamy green paste, and that the mission has ended in failure.

Edited September 4, 2012 by grynspan
Tweaks to the formula

[Hremsfeld]

To be clear:

Put Rocket A into LKO and empty it of kerbanauts.

Send Rocket B out of Kerbin's SOI; Make it have an apoapsis of at least 1Gm = 1,000,000 km further than Kerbin's.

Return Rocket B to Kerbin's SOI and establish an orbit. (Stable: Optional)

Transfer crew from Rocket B to Rocket A.

De-Orbit Rocket A, as close to KSP as possible, without turning your kerbanauts into jelly.

No MechJeb, except to view stats. I'm presuming this also means we can't use it to de-orbit any lower stages on Rocket A.

No Fuel Bug exploitation. Did I miss anything?

By the way, there is a fix available for the fuel bug:

http://kerbalspaceprogram.com/forum/showthread.php/16439-0-16-0-Hacky-Fuel-Consumption-Bug-Fix

Edited September 3, 2012 by Hremsfeld
Fuel Bug Fix

[illectro]

Well I've done a simulated interplanetary mission, I travelled out to almost 30GM, and returned to kerbin's SOI, and then put crew down on Kerbin, the Mun and Minmus before returning out to 30GM and back to splashdown safely on Kerbin (40km from KSC!)

I did have mechjeb, but didn't use anything but smart A.S.S. in the end, although I could have probably turned it off completely. And of course I had the fuel mod.

[grynspan]

Sounds about right. Remember for those of you who don't like metric: 1Gm=1,000,000km=1,000,000,000m. Though if you're trying to reach another ship in a stable orbit, your orbit will be almost identical when you match speed and altitude. So stability isn't really optional there.

[grynspan]

Well I've done a simulated interplanetary mission, I travelled out to almost 30GM, and returned to kerbin's SOI, and then put crew down on Kerbin, the Mun and Minmus before returning out to 30GM and back to splashdown safely on Kerbin (40km from KSC!)

It's always the best when you land within rendering distance of the launch tower, innit?

I think the relatively unique thing about my approach is the use of separate vehicles for separate purposes. Once we get planets, I plan to have three vessel designs:

1) An LKO lifter that brings crews up to and back from LKO.

2) An interplanetary cruiser that cannot safely enter an atmosphere or land, but which has sufficient fuel/thrust for multiple trips between worlds.

3) A lander sent out to orbit another planet, which can then land on the surface of that planet and return to a low orbit.

My crew head into space on 1), travel to other planets on 2), "beam down" and back up on 3), return to Kerbin orbit on 2), and return to Kerbin surface on 1).

By applying the separation of concerns principle, I don't have to carry fuel to push around a landing module and extra decouplers and parachutes and whatnot. If you think about it, the Apollo program had a similar approach with the CM, SM, and LEM.

[grynspan]

I'm presuming this also means we can't use it to de-orbit any lower stages on Rocket A.

That's fine--unless you're going to collide with one, they're just space junk and can be ignored/removed without affecting the simulation.

[Hremsfeld]

Well I've done a simulated interplanetary mission, I travelled out to almost 30GM, and returned to kerbin's SOI, and then put crew down on Kerbin, the Mun and Minmus before returning out to 30GM and back to splashdown safely on Kerbin (40km from KSC!)

I did have mechjeb, but didn't use anything but smart A.S.S. in the end, although I could have probably turned it off completely. And of course I had the fuel mod.

Well, shoot. I saw those videos, which are where I learned to wait for the sun, the proper distance to go to meet back up with Kerbin, and got a d'oh! moment with regards to remote-controlling probes. I'd used the R202 component on MechJeb to de-orbit mostly-drained stages I didn't want cluttering up the space between Kerbin and the moons, but hadn't thought of making it its own seperate craft until I saw those. So, thanks for having an awesome channel, and congrats on finishing your mission, but it'd feel too much like industrial espionage/plagarism for me to take this on, now.

That said, wouldn't it have been simpler to calculate Kerbin's period, and make your interplanetary period twice that, rather than mucking about with SMA-issues?

Edited September 4, 2012 by Hremsfeld