Rescue mission possible?

[dr_jt]

I wasn't sure if this should go here or in Gameplay Questions.

Here is my problem.

I have a ship about halfway to the Mun that is without power so I can't do the burn that will allow Mun capture.

Is it possible to get another ship to them for rescue?

If they don't get shot into deep space can an intercept be done on a large elliptical orbit? I've really only done intercepts on ships in nice circular orbits.

Edited November 1, 2013 by dr_jt

[Richy teh space man]

Probably should go under game play questions

If your ship is piloted and you have thrust vectoring, you can steer the ship that way by just applying a low amount of thrust until your pointed in the right direction, then fire up the engine.

Also, some engines recharge the battery when started up too.

[NASAFanboy]

Probably should go under game play questions

If your ship is piloted and you have thrust vectoring, you can steer the ship that way by just applying a low amount of thrust until your pointed in the right direction, then fire up the engine.

Also, some engines recharge the battery when started up too.

If there is no power, them you can't fire the engine.

Is the SAS off?

If so, EVA a Kerbal and ram the ship, hopefully exposing the solar panels to the sun. That is, IF you out solar panels on it.

[jsfalconero]

It's possible, just harder. The same basic principle holds as with docking in nice circular orbits, but you might have to wait a while longer than usual to generate a close approach.

It will also likely take a lot more dV than your original craft had because you will have to launch into one orbit (probably inside the orbit of the first) then set up your close approach (which will likely involve a burn at a sub-optimal time), then match velocities (also likely at a sub-optimal time).

Then there's the added risk that Jeb will get impatient and get out and use his RCS pack to push the thing toward the retrograde whilst at apoapsis, thereby throwing of your intercept (and possibly rescuing himself, or throwing himself off into deep space, it's a tough call really

[Scotius]

This is the reason i place at least one RTG on every ship i launch - no matter how much batteries and solar panels it carries. Stuff happens all the time.

[Richy teh space man]

If there is no power, them you can't fire the engine.

Is the SAS off?

If so, EVA a Kerbal and ram the ship, hopefully exposing the solar panels to the sun. That is, IF you out solar panels on it.

You can fire the engine if there is no power, so long as the capsule is manned.

[-RanZ-]

a rescue is always possible as long as the vehicle is in an orbit and not on a trajectory to crash

[boomerdog2000]

You can fire the engine if there is no power, so long as the capsule is manned.

Unless it's an ion engine, but yes all other engines can activate without power as long as there is a kerbal in the capsule.

[nadreck]

Been there with unmanned craft and manned ones (no fuel either once). Rendezvous between LKO and an eccentric orbit is quite easy, between two different eccentric orbits is possible but trickier, I find the best bet is to adjust the orbits so that the inclination is the same first, then to perform a manneuver to adjust get a closest approach when the rescue craft is at a point in its orbit closest to the PE of the target craft. Go for the closest approach when the orbits almost match, not the first closest approach that comes up as you add prograde vector in the "add manneuver mode".

[nadreck]

Oops, just realized I didn't address the urgency of getting to it and rescuing despite the fact that it was bound for a Mun encounter that will send it out of the Kerbin SOI. There are two possibilities:

1) wait for it to go, then treat it like a rendezvous with another planet

or if you are bold and have significant delta-V

do what I suggested above, but once on a course that is closely matching the target vehicles add a manneuver right in front of your craft and adjust the lateral and prograde velocities of that manneuver to be on a hyperbolic orbit with a rendezvous point before the Munar SOI, depending how far out the target vehicle is when you start you could do this with as little extra delta-V to kill as 500m/s at rendezvous.

[dr_jt]

The problem came about because I forgot to extend the panels. I think the ship will crash into the Mun or slingshot off into space. so I can't wait until PE to intercept. So I guess the question is, can I intercept while the ship is halfway to the Mun and before it crashes or gets shot off into deep space?

I'm not really seeing any way that it could be done. The rescue ship would have to be a lot faster than the stranded ship and I don't see how to do the intercept if the rescue craft is in any kind of orbit. I also may be trapped in the "box" which is why I asked the question. I was hoping for some outside the box ideas.

[dr_jt]

I was writing while you were so I didn't see your second post. I've been thinking of seeing what orbit it will be in after it passes the Mun and then treat it as a planet intercept. The problem with that is it may crash into the Mun. If it looks like it will crash I'll attempt to have a kerbal push it and attempt to get out of Kerbin's SOI.

I'm not wedded to this mission and don't care if I just revert it back to the VAB. I just wondered if a rescue was possible before Mun encounter. I'll give it a rescue shot tonight and post what happen. Most likely it will be a crash into the Mun.

[-RanZ-]

unlikely, you would have to have the rescue ship going much faster than the dead ship to intercept it in time and then slow down for a randevu... if you can pull that off I think Scott Manley would even be proud! If your PE is going to be a crash with the moon EVA the kerbal and see if you can nudge the ship enough to miss the moon and rescue it in the sun's orbit.

[EKG]

Wait, if you can EVA a kerbal to get out and push couldn't the kerbal just extend the solar panels manually, or has that ability been removed? I haven't actually had to do it in quite a while.

[Eric S]

There's something someone is missing. That someone may be me. Is this a manned ship? If so, even with no power, you can power up the engines (which may provide power) or you could just extend the solar panels (not even requiring an EVA). Both of these work in a manned ship with no power (just tested both to make sure it's still the case in 0.22). Neither work with an unmanned ship with no power.

You may have a mod enforcing power requirements for those activities (I'm pretty sure that there's at least one of them).

Other than that, it would be possible to catch up with the craft, but you'd need a good bit more delta-v than the original craft had, and every rendezvous method I know of involves orbits instead of doing it in a single pass, so you'd be winging the intercept. Possible, but not trivial, especially without practice doing so.

[Hodo]

I have done a deep space rescue. I don't ever want to do it again, it took forever. But the trick is timing the orbit right to match the orbit of what you are trying to rescue. And then making sure your rescue craft has the fuel to get there and back safely. The worst docking attempt I had was with a pod that had NO power and was tumbling in space. Again it is possible, it takes hours to do it.

[jklier]

I've got a Kerbal in orbit around Kerbin right now with no fuel or power left. Ran out of fuel during my final retrograde burn after a visit to the Mun. I just finished constructing a unmanned rescue ship that has a "net" built from structural girders and struts (I don't have any docking ports yet in career mode). I plan to send this ship up, sync orbits, then capture the capsule in the net and perform a retrograde burn with the rescue ship.

[jduchock]

I wasn't sure if this should go here or in Gameplay Questions.

Here is my problem.

I have a ship about halfway to the Mun that is without power so I can't do the burn that will allow Mun capture.

Is it possible to get another ship to them for rescue?

If they don't get shot into deep space can an intercept be done on a large elliptical orbit? I've really only done intercepts on ships in nice circular orbits.

I had a similar problem with Jeb and ended up sending a double capsule rig with Bill up to get him. Jeb had to EVA to get into the spare capsule and use it to get home, but it worked without much problem. I was also able to use the science points Jeb had gained to build Bill a better ship with batteries.

[dr_jt]

There's something someone is missing. That someone may be me. Is this a manned ship? If so, even with no power, you can power up the engines (which may provide power) or you could just extend the solar panels (not even requiring an EVA). Both of these work in a manned ship with no power (just tested both to make sure it's still the case in 0.22). Neither work with an unmanned ship with no power.

Manned ship with one Kerbal. Does turning on the engine depend on which engine used? I know I've started an engine before with no power but it didn't work with this one for some reason I'm not sure of. I did an EVA to extend the panel but I didn't see the option to do so. I've never tried it before. Do you need to be in the correct orientation and position?

You may have a mod enforcing power requirements for those activities (I'm pretty sure that there's at least one of them).

Other than that, it would be possible to catch up with the craft, but you'd need a good bit more delta-v than the original craft had, and every rendezvous method I know of involves orbits instead of doing it in a single pass, so you'd be winging the intercept. Possible, but not trivial, especially without practice doing so.

No mods in this install. I have several installs with different mods. It's been so long since I've used only stock parts and no mods that I wanted to see if I could still do it. I'm not sure I could build something that could get out there and then slow down enough. The stranded ship is a little past half way to the Mun right now. I would have to have something with a really high delta v to even get out there before it hit the Mun and I really doubt I could accomplish the intercept in one shot and one shot would be all I would have time for.

This was really more of a theoretical brain game to see if anyone had any ideas that I hadn't come up with. I will take a quick look tonight but I really think this Kerbal is lost. I never managed to do a deep space rescue but this was the first time I've run out of power half way to the Mun and I figured maybe somebody had done such a rescue. Maybe I'll just see if I can get the Kerbal into Mun orbit using RCS and then attempt to rescue him. I just wish the Nav ball was available to a Kerbal doing EVA.

[Eric S]

Manned ship with one Kerbal. Does turning on the engine depend on which engine used?

It only matters if it's an ion engine, and I doubt you'd try that. Do you have a fuel bar in the staging area for the engine, and does the throttle indicator next to the navball respond to left-shift and left-ctrl?

It really sounds more like you've hit a bug that people have seen from time to time where for no apparent reason, a ship just becomes uncontrollable. You should be able to throttle up an engine no problem, and you shouldn't even have to EVA to extend the solar panels if it's a manned craft, regardless of the power situation. I think a save and reload might fix it if that's the case, it might actually take quitting the game and starting new.

I hadn't heard about that bug much lately, and this is the first time I've heard of it hitting someone running 0.22.

[Lazro]

Get up close to the panel. Right-click. "Extend Panel" should come up.

[RexKramer]

I have another possible solution, with no guarantees of success.

It seems you have an upcoming encounter with Mun, with no ability to power the ship. In your case, the power seems to be lack of electric, for which others have posted possible solutions.

Another possible way to keep the Kerbalnaut from exiting Kerbins SOI would be to attempt to put him in orbit around Mun, without his craft. You would be surprised how much delta V you have from a jetpack. The problem here is the difficulty controlling and aiming your jetpack RCS bursts, but it can be done. If you manage to put him in orbit around Mun, his retrieval is likely going to be much easier than getting him back from outside Kerbins influence.

I've had success with a similar situation. Had a lander depart Mun, unfortunately ran out of fuel long before reaching orbit. The resulting unpowered descent would have been fatal, so there was nothing to lose by going on EVA and trying for orbit with the Jetpack. The orbit was far from circular, but the Kerbalnaut survived. Must have been a very long 5 days waiting for a rescue ship to come scoop him up, floating around in his space suit.

Try very hard to save at least a tiny amount of jetpack RCS fuel so you can maneuver to the rescue ship' entry door...

[dr_jt]

Well it must have been a glitch. When I reloaded the saved game everything worked fine. Kerbal is now back on Kerbin chewing out the engineers for using electronics salvaged from old solar powered lawn ornaments. It was my first sandbox game in .22 so I thought they may have changed how things worked.

Thanks for all the suggestions.

[Talavar]

IF and when your other ship is eccentric to kerbin after encountering the mun, Boost to match the ships periapsis height. Only AFTER you do that do you do your plane change. Either way your going to have to be at that orbit height, and it takes less fuel to plane change the higher you are in orbit. Once you do those two things, click on your orbit right at the targets peri node and play with delta V to figure out how much thrust you need to rendezvous with your target. This is all assuming the mun encounter doesn't whip your original ship out of Kerbins SOI.

Edited July 22, 2014 by Talavar