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# Is it possible to get back from eve's orbit to kerbin with only 464 m/s of delta v?

## Question

Okay so what happened is i was going to Gilly with what i thought was well enough delta v which i was wrong.

i landed then noticed i didn't have enough delta v so what i did is i used about 18 m/s of delta v and got into an orbit with eve at about 48 kilometers at apoapsis and about 13 kilometers a periapsis.

Right now i have 464 m/s of delta v and have completed all of my science. Any way to get back to kerbin? Here is a screenshot of the current situation

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1 hour ago, CoreGaming said:

i landed then noticed i didn't have enough delta v so what i did is i used about 18 m/s of delta v and got into an orbit with eve at about 48 kilometers at apoapsis and about 13 kilometers a periapsis.

Right now i have 464 m/s of delta v and have completed all of my science. Any way to get back to kerbin? Here is a screenshot of the current situation

My first though was: "No from that low an orbit you don't." Then it occurred to me that 48 km is within the atmosphere of Eve. But your screenshot says that you are in an 48 thousand km by 13 thousand km orbit, just next to Gilly. From there it can be done in theory: from your apoapsis you need about 200 m/s to drop your periapsis down to just above Eve's atmosphere, to say 100 km - 150 km. If you then burn at the periapsis of this highly elliptical orbit you need less than 250 m/s to leave Eve's SOI with enough speed for a Hohmann transfer to Kerbin, where I hope you can aerobrake. (If you can't aerobrake, then you won't be able to capture at Kerbin with that amount of fuel!) The problem with this is, that you have to get lucky for everything to line up: the ejection angle from Eve's SOI is essentially fixed by the need to do the two burns at (or at least close to) the apoapsis of your current orbit and the periapsis of the resulting, elliptical orbit. And this direction needs to line up with Eve's orbit to get you on a Hohmann transfer and a transfer window from Eve to Kerbin. My approach would be to get onto that elliptical orbit, set up a maneuver node at the periapsis with 230 m/s or so, and then use the "next orbit" button until I get a solution that is close enough that I can fine-tune it to an encounter with Kerbin.
(Well, actually I would just get back to Gilly's SOI, and send a rescue mission. But that wasn't your question.)

Another version would be to use gravity assists to get you back. But I suck at those...

P.S. Please don't change the default font size of your text. For me the large font is just annoying.

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Alright thanks for the input i should be able to do this with a few tries.

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14 hours ago, CoreGaming said:

Alright thanks for the input i should be able to do this with a few tries.

More like a few hundred tries.

Or send a refuel probe there.

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Easily enough, it'll just take awhile.

I'd do it a different way than the other poster - instead of modifying your original orbit at all, just wait until your original orbit's periapsis IS where you'd want to burn anyway for an ejection into a solar orbit with an apoapsis at Kerbin's radius (it doesnt matter for now if Kerbin is in the wrong place).  If you already have a 48km AP, this should take next to no fuel.

Now, you're in a solar transfer orbit with the PE at eve's radius and the AP at kerbins radius - the challenge here becomes fixing the declination - if you're lucky, the ascending or descending node is near where you're intersecting kerbin, otherwise, you either have to pay for it with fuel (use the mode at a higher alt), or plan a re-intercept of eve and use the planet to bend your orbit.

Finally, you should be able to gauge Kerbin's orbit relative to your own, and line up an intercept using your remaining fuel.  As the other guy said, if you're not equipped to aerobrake, you might be SOL, except for maybe shooting at the moon and getting a nice speed drop ala:

Edited by panzerknack

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