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Probe on extremely high solar orbit - wat do?


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Hi Guys!

So a weird thing happened to me:

I designed a high-deltaV/low mass probe for exploration of the Kerbol system. I sent it off to Jool where I parked it in a seemingly stable orbit. Then I left it there and got busy with other things. As I checked back - it was out of the Jool system at an extremely high speed!

My apoapsis is currently at 998078 Gm or 998.078.000.000 km, which I will reach in 117 (kerbal-)years.

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I can't really tell what happened. It could have been some weird encounter with a Jool moon that kicked me out, or the game simply glitched the position/velocity vector (happened a few times now). But that doesn't really matter now.

What matters is that I am in a unique position to do some awesome things now, since I have 12526 m/s of Delta-V left!

Here are some ideas of what I could do:

  • Burn full retro at apoapsis, burn towards the sun until I'm empty and test out the theoretical limits of lithobraking
  • Burn full prograde now and send the probe off on escape trajectory, possibly discovering different Star systems. Since I have no idea where they would be, that would be pretty unlikely. Also, since it was designed as in intra-system probe, I did not pack a plaquette with the descriptions of Kerbalkind. I hope any Kerbalians that would encounter the probe will figure it out from the tech.
  • Burn now to raise the apoapsis to 3.56*10^14 m, and burn there to circularize. That's pretty much the SOI limit of the sun and would make the probe the object furthest away from Kerbal civilization - permanently! Unfortunately getting to the apoapsis alone would take 233 years :(

What would you guys say? What would you do in this scenario? Any Ideas?

Edited by Kobymaru
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Reload your last quick save? Seriously, the issue isn't so much the dV remaining, it's the amount of time it's going to take to get that probe back. It'll be much much quicker to just relaunch a new probe towards Jool.

And you're almost certainly correct that it was an encounter with one of Jool's moons that caused the probe to be ejected from the SOI. Thats why it's best to orbit one of the moons instead of Jool itself, or to orbit Jool at an altitude that never crosses the moons' orbits, or even their SOIs.

Edit: Aaaaaaand ninja'd

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Reload your last quick save? Seriously, the issue isn't so much the dV remaining, it's the amount of time it's going to take to get that probe back. It'll be much much quicker to just relaunch a new probe towards Jool.

And you're almost certainly correct that it was an encounter with one of Jool's moons that caused the probe to be ejected from the SOI. Thats why it's best to orbit one of the moons instead of Jool itself, or to orbit Jool at an altitude that never crosses the moons' orbits, or even their SOIs.

Edit: Aaaaaaand ninja'd

Yeah, I'd agree. It's much more likely that you had an inadvertent moon encounter rather than a kraken attack. You probably got an unplanned gravity slingshot.

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Yea, that probe is lost.

Solar pannels don't work that far out, so you can forget any kind of manouvers at apoaps.

You could try a hard prograde burn to cancel out your velocity and fall down to the sun, but I don't think you have enough deltaV to get back into an orbit. So it's probably best to chalk it up as a loss and launch a new probe

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Now that I've bothered to actually read your entire post...

Burn now to raise the apoapsis to 3.56*10^14 m, and burn there to circularize. That's pretty much the SOI limit of the sun and would make the probe the object furthest away from Kerbal civilization - permanently! Unfortunately getting to the apoapsis alone would take 233 years

I would like to see this. :)

You might be able to use some of that dV to get out there a lot faster (escape trajectory), then burn to readjust your orbit once you get out there. You can probably cut into that 233 years.

Edited by Claw
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Yea, that probe is lost.

Solar pannels don't work that far out, so you can forget any kind of manouvers at apoaps.

Well,there's no other star systems, and solar panels won't even work that far out, you should test the extreme limits of lithobraking. :P

I am sure there are star systems out there! The universe is big. I want to believe. Do solar panels really not work? Has anyone ever tried? I don't care if the burn takes long, if it takes 134 years to get there, a few hours of burn are relatively short.

Welp, the kraken was playing around with your probe.

If I were you, I would use quickload, as I quicksave each time I accomplish a new step in the mission.

Well that would make sense, but the problem is that I don't want to check each of my 25 flights for every operation, thats very tedious. The damn kraken screwed up 3 of my missions, where a ship was on an encounter trajectory but I had to use all my planned dV to correct the encounter.

And you're almost certainly correct that it was an encounter with one of Jool's moons that caused the probe to be ejected from the SOI. Thats why it's best to orbit one of the moons instead of Jool itself, or to orbit Jool at an altitude that never crosses the moons' orbits, or even their SOIs.

Yeah, I'd agree. It's much more likely that you had an inadvertent moon encounter rather than a kraken attack. You probably got an unplanned gravity slingshot.

I know of that problem, but can it really cause so much velocity without glitches? I mean, look at the apoapse! The kick must have been huge. I guess it was the kraken, wasn't it?

Reload your last quick save? Seriously, the issue isn't so much the dV remaining, it's the amount of time it's going to take to get that probe back. It'll be much much quicker to just relaunch a new probe towards Jool.
You could try a hard prograde burn to cancel out your velocity and fall down to the sun, but I don't think you have enough deltaV to get back into an orbit. So it's probably best to chalk it up as a loss and launch a new probe
What you could do is burn retrograde at apoapsis to get the Low over the Sun science!

Well, it's not the science I'm after, I have a huge jool mission going on and some other probe for the low sun passover. This one's just for fun :)

Now that I've bothered to actually read your entire post...I would like to see this. :)

You might be able to use some of that dV to get out there a lot faster (escape trajectory), then burn to readjust your orbit once you get out there. You can probably cut into that 233 years.

Now that's an Idea I like. I guess for SOI+circularization I'd need around 800 m/s, and I could use the rest to get there faster. Except if the solar panels don't work that far out. Then it won't work.

Burn at Kerbin, and then test the limits of aerobreaking.
Oooh, now that sounds interesting. Or better Eve! But I guess it'd be pretty hard to hit a tiny planet from that far out. But just imagine the huge ball of fire when the probe gets torn apart by ginormous g-forces :D Edited by Kobymaru
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So... option 3 is out because you won't have any control over the probe at apoapsis.

Option 2 seems honestly kind of boring, because there's nothing out there.

Option 1, as written, might not work due to solar panels not working that far out... BUT if what you want to do is crash your probe into the sun at near-plaid velocity (which sounds awesome)... you wouldn't necessarily have to make the burn at apoapsis. That would just be the most efficient place to do it. In fact, I bet you could set up that trajectory right now if you wanted, then ride out to apoapsis and come back in. Maybe even kick your speed up a little on the return trip once you've regained control.

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You probably got booted out of the Jool system by Tylo. That's a big heavy moon and can really give you a strong gravity assist. People have used Tylo assists to get them on their Kerbin return trajectories, which is comparable delta-V wise to the situation you're in.

As mentioned, power is a big issue. According to the wiki, if you go more than 206 Gm from the Sun, your solar panels will cease generating power. Thus, if you want to establish a wider orbit you will need to "hibernate" your probe, by right-clicking at least one battery and disabling it. I suggest disabling all the batteries this way to give yourself more to work with. You'll then have to count on the nuclear engine for all your manouvering, the ion engine would flatten your batteries way too fast.

If you stay within that distance limit you can use the ion engine, though you might be in for some slow burns. You've got enough delta-V to establish a polar or retrograde orbit round the Sun, which would be fun. If you fancy a big impact, get in a solar retrograde orbit with periapsis level with Moho's orbit and then make a correction at some point to get the impact course. You'll hit it at a closing speed in excess of 25 km/s.

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I am sure there are star systems out there! The universe is big. I want to believe. Do solar panels really not work? Has anyone ever tried? I don't care if the burn takes long, if it takes 134 years to get there, a few hours of burn are relatively short.

Kerbol's SOI is infinite, sorry :P

And no, solar panels produce less power the further away you are. I never got around to testing it myself, but I believe you already need RTGs out at Eloo. You are going alot further than that.

Well that would make sense, but the problem is that I don't want to check each of my 25 flights for every operation, thats very tedious. The damn kraken screwed up 3 of my missions, where a ship was on an encounter trajectory but I had to use all my planned dV to correct the encounter.

Try Kerbal Alarm Clock

It will let you keep track of manouvers and stuf, and you can set it to keep track of SOI changes and stuf for you

I know of that problem, but can it really cause so much velocity without glitches? I mean, look at the apoapse! The kick must have been huge. I guess it was the kraken, wasn't it?

It's probably that you timewarped at very high speed through a gravity kick you didn't notice. Funny things happen when you are at high timewarp during SOI changes (because the craft might already be deep in it's new SOI by the time KSP notices the SOI change)

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Laythe and Tylo can both very easily spit you out of the Jool system with enough speed to put you into solar escape, or put your periapsis down below Moho.

I would plop a maneuver node down at the point where you orbit crosses Jool and look for another Jool encounter. From there you can get to wherever you like for pretty much zero delta-V cost. Yes, this will mean waiting a while, but there's not much you cna do about it, a direct abort will cost you a huge amount of fuel.

If you don't have an RTG power will be an issue, but you can disable all electricity consumption on all parts with power storage (so the probe and any batteries - right click and disable flow) and then re-enable flow near apoapsis so that you can peform the burn.

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Option 2 seems honestly kind of boring, because there's nothing out there.

You are right, I guess that's out too.

You probably got booted out of the Jool system by Tylo. That's a big heavy moon and can really give you a strong gravity assist. People have used Tylo assists to get them on their Kerbin return trajectories, which is comparable delta-V wise to the situation you're in.

One day I shall use it on my regular Jool travels, although I have to figure out a way to predict reliable constellations.

As mentioned, power is a big issue. According to the wiki, if you go more than 206 Gm from the Sun, your solar panels will cease generating power. Thus, if you want to establish a wider orbit you will need to "hibernate" your probe, by right-clicking at least one battery and disabling it. I suggest disabling all the batteries this way to give yourself more to work with. You'll then have to count on the nuclear engine for all your manouvering, the ion engine would flatten your batteries way too fast.

Thanks for the ideas and the numbers!

Kerbol's SOI is infinite, sorry :P

It's infinite, but every celestial body has an escape trajectory. If I go faster than that, I can escape even kerbol.

Try Kerbal Alarm Clock

It will let you keep track of manouvers and stuf, and you can set it to keep track of SOI changes and stuf for you

That's just the thing: I did use it, and I trusted it completely. I set up an encounter, set an alarm at SOI change. When the alarm went off, I was millions of kilometers away from the target. I'm pretty sure it was some sort of kraken.

It's probably that you timewarped at very high speed through a gravity kick you didn't notice. Funny things happen when you are at high timewarp during SOI changes (because the craft might already be deep in it's new SOI by the time KSP notices the SOI change)

Yeah, I guess it was something like that.

Alright guys, thanks for the answers! I will post results of what happened eventually. In about 300 years ;)

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