Has anyone done this before?

[ArmchairPhysicist]

One of my most ingrained fears in this game (aside from finding out the hard way that you didn't pack parachutes) is botching your munar insertion and getting that "new record, you have achieved orbit around the sun" message.

Ive done this once or twice, but never recovered from an accidental escape trajectory. I always end up reverting the flight.

Has anyone done this in career, AND brought the kerbal back home? I know it would be possible by just waiting a few hours for the ship to enter kerbin's SOI again. Also possible to launch a new mission to retrieve the botched rocket. 

But has anyone done that?

[JoeNapalm]

 

In practice, this is a tough thing to do.

As I related in another post, recently, the black line on my Kerbol ribbon is from one of Anand Kerman's clones that I tried, repeatedly and unsuccessfully, to rescue from just such an event (never gave up but eventually lost that save game to the Kraken).

It's basically an interplanetary orbital rendezvous. Your target is tiny, on the same general orbital plane and path, and has no gravity well.

I actually got an unmanned rescue ship out to Anand, but I used way more DV than I anticipated synchronizing orbits with his disabled ship, and basically just gave him a more comfortable ship to be stranded in.

With the knowledge and experience I've gained since then, I feel I could have done it, but it's definitely not an easy task.

 

-Jn-

[Snark]

2 hours ago, ArmchairPhysicist said:

I know it would be possible by just waiting a few hours for the ship to enter kerbin's SOI again.

Well, yes, in general it's possible for a ship that leaves Kerbin's (or any planet's) SoI with a low relative speed to re-enter the SoI "naturally"... if it leaves at a very low relative velocity to the planet.

However... if the reason you're leaving is a botched munar insertion and you've got an unintended slingshot going on there-- it ain't gonna happen, unless you get super lucky on the velocity / timing and it happens to wander back into Kerbin's SoI years later.  Reason:  this type of ejection will leave you with plenty of excess escape speed.

So, this is generally not a recovery option.

2 hours ago, ArmchairPhysicist said:

Also possible to launch a new mission to retrieve the botched rocket.

Certainly possible to do in principle, but I suspect it's pretty rare in practice.  Reason:  Launching a rescue ship to rendezvous with an ejected "stranded" ship takes some fairly skilled navigation.  It's not impossible, or even ultra-difficult-- but it is significantly more challenging than getting a good Mun intercept in the first place.

So, the people who have the skills / practice to pull this off probably wouldn't have accidentally ejected in the first place, and the people who are new to the game and accidentally went sailing away would probably find it unpleasantly difficult to do.

 

...All of the above said, though, I'm curious about your use case.  If you botch a Mun insertion... it doesn't take a lot of dV to "semi-recover":  i.e. get the ship to a stable orbit around Mun or Kerbin (even if it's not what you originally wanted when you launched), so that it's reasonably rescuable.  Shouldn't take much fuel.  In either case, you then have a craft that you can retrieve at your leisure with a rescue ship, much more easily than if you had to go after it outside of Kerbin's SoI.

However, without knowing exactly what sort of situation you mean by "botched", it's kinda hard for me to tell how relevant the above advice is.  Can you give more specifics about the kind of trajectory you're talking about?  When it "goes bad", exactly how does it go bad?  i.e. what's your trajectory?  ("I wanted to do X but Y happened instead.")

[ArmchairPhysicist]

I ended up just reverting, one of these days I'll play through without the ability to revert. He ended up not far outside of kerbins orbit, can't give specifics because he's not there anymore. The best rescue mission I've done was a munar landing that went bad. Poor Jeb used too much fuel and didn't have the delta v to make the return trip. I launched a modified version of the same rocket that got him there, entered orbit and had jeb eva to the new two seater space craft.

In fact the rescue went so well I've considered it as a mission possibility for early game simple manned missions. One rocket has the lander, with enough fuel for the landing and return to munar orbit. Second rocket launches soon after the first, but only stays in orbit to take the science and mun walker home

[Enorats]

Wait, how is it possible to botch a munar insertion like that? Do you mean you botched the insertion burn and either burned the wrong way or didn't have enough delta-v to achieve orbit (leading to the Mun slingshotting you out of SoI), or do you mean you missed the Mun entirely? Either seems rather unlikely to me, unless you're playing without some sort of delta-v calculator and had no idea what your ship could handle I guess.

I think the closest I've come was a no revert save where I was sending my first lunar mission of the career to a new mod's moon (Iota). I swung in close and was intending to combine my insertion and landing burn but came in too low. I hadn't mapped the unfamiliar moon's topography with ScanSat before so I didn't anticipate a giant mountain right at my periapsis. Noticed it just as I came out of time warp, oriented radial plus and burned.. then impacted the surface about 5 seconds later at greater than orbital velocity. Lost the engine and entire lower half of the craft, but the kerbals all survived in a command pod with no delta-v at all. They had to be rescued from an oddball orbit, but still within Kerbin's SoI.

[regex]

6 hours ago, ArmchairPhysicist said:

One of my most ingrained fears in this game (aside from finding out the hard way that you didn't pack parachutes) is botching your munar insertion and getting that "new record, you have achieved orbit around the sun" message.

This should, in practice, never happen. If you're skilled enough to create a free-return trajectory from the Mun you don't have to worry about this and if you're planning on returning from Munar orbit/surface you already have the delta-V to recover from a botched intercept.

3 hours ago, Snark said:

So, the people who have the skills / practice to pull this off probably wouldn't have accidentally ejected in the first place, and the people who are new to the game and accidentally went sailing away would probably find it unpleasantly difficult to do.

^ This.

I've done this sort of thing after a Duna flyby went slightly wrong, didn't account for mostly-bad return options. Stock doesn't have very good planning tools... I see that I did pick up some milestones during the refueling mission though. Very much a possible thing to do and not entirely difficult once you've done a few rendezvouses.

Spoiler

 

Edited April 27, 2017 by regex

[Zeiss Ikon]

I didn't find rendezvous "in orbit around the sun" any harder than rendezvous in LKO, just a lot slower (and I've done it a total of once, if you don't count a Duna flyby with gravity assist return).  Took almost a quarter year to meet the asteroid I was hunting, and I got a low-velocity intersection on the first orbit -- IOW, it could have been MUCH longer.

The problem is, if you accidentally gravity assisted of Mun into interplanetary space, the ship that went out probably had a pretty high velocity -- that means you need an even higher velocity to catch up quickly (or a lower intersecting orbit if you're willing to wait years), then something like twice that velocity in dV to get home again.  This isn't hard, at least if you can rendezvous and dock in Kerbin orbit -- it just takes a lot of game time, and requires a ship with very long legs.

[Enorats]

Such a rendezvous also generally requires an order of magnitude greater accuracy. The greater the orbital period, the greater accuracy is required to achieve the same distance at rendezvous.

While a .1 m/s difference doesn't matter all that much in LKO, a solar rendezvous might require accuracy as low as .01 or .001 m/s variance from the target burn to get a reasonable proximity without further adjustments at closer range.

[Leafbaron]

Never botched a Munar insertion as you described. However, I have high altitude rescue missions that were not properly attended to and encountered the Mun's SOI and get launched into an escape trajectory from Kerbin. I was able to rendezvous with the vessel while it was still on a hyperbolic trajectory around the Mun. I was able to capture it and slow down enough to just kiss Kerbin's SOI and return back.  

[GarrisonChisholm]

One thing to consider though makes this even less likely to need to be completed if you are playing with Life Support.

A botched (facing prograde + inattention/distraction) Munar Insertion that kicked you out of Kerbin's SOI would put you onto a path that wouldn't take you soon back to Kerbin, but the player who might make such an error and also was dealing with LS would have a Very difficult time.

Such a player has likely just cobbled together their first lunar landing attempt, and is hoping that the ~ 10 days of supply they have on board will suffice for the trip.  If their poor Kerbalnaut suddenly finds themselves cast out into interplanetary space, then a Very complex craft (from their perspective) needs to be constructed from scratch and launched Very quickly.  In fact, with KER, I believe such a rescue would be impossible.  A craft to get to interplanetary space, rendezvous, and return with sufficient supply for the mission would seem to me to be a tall task for a relatively new player.

 

I almost said " @Snark is on the money", but then this would be stating a case which is always empirically known to be true.

Edited April 27, 2017 by GarrisonChisholm

[MR L A]

7 hours ago, ArmchairPhysicist said:

One of my most ingrained fears in this game (aside from finding out the hard way that you didn't pack parachutes) is botching your munar insertion and getting that "new record, you have achieved orbit around the sun" message.

Ive done this once or twice, but never recovered from an accidental escape trajectory. I always end up reverting the flight.

Has anyone done this in career, AND brought the kerbal back home? I know it would be possible by just waiting a few hours for the ship to enter kerbin's SOI again. Also possible to launch a new mission to retrieve the botched rocket. 

But has anyone done that?

weird.. I did this literally an hour ago haha

fortunately my insertion stage sill had 700 dV left and my lander had over 1000... so as soon as I realised what had happened, I burned a combination of retrograde and radial out (my orbit was taking be closer to the sun) - allowing Kerbin to catch-up with my craft. It was not an efficient way to manoeuvre, but I wanted Jeb back asap, managing so in approx 20 days (more efficient manoeuvre's would have be waiting the best part of a year).

Yes this was in career, also, I play with reverts turned off, so I HAD to get Jeb back!  

[Alshain]

I'm with @regex on this.  Any Mun trip I plan would put me on a return trajectory rather than an ejection trajectory if I somehow forgot to burn.

[Piper]

I've definitely done stuff like this, or at least similar enough, and brought them back, although I never have had to send someone out to get them, they've always had enough fuel to get them back themselves.  In particular coming back from Minmus.  A regular Hohmann transfer from Minmus can take a few days, so I very often do a burn that puts me on a faster hyperbolic trajectory that takes me back in a day or less.  It's been a long time now, but I have had cases where I've accidentally had my alarm set to SOI change instead of nearing periapsis, causing me to completely miss my re-entry.  However, I always leave a little bit of dV (~100m/s), and have been lucky enough so far that the few times it has happened, the fuel I've had has been enough to bring myself back to Kerbin relatively quickly.

I can't remember if the last that's happened to me with a manned craft I was using life support, but I definitely do now, and as others have commented, that definitely complicates things.  If the craft can bring itself back, then it's not likely a problem, I'm generally pretty generous with how much life support I dish out, but if I have to build a rescue craft, then I'm really likely to run into problems.  I also use KCT, so I can't build craft instantly, even if I spent funds to rush the build I have to wait for it to be built, which means the craft will be farther out and harder to reach, which means I need to incorporate more dV and more life support, which means it will take longer to build, and it can snowball from there.

[purpleivan]

I had something like this when I had a contract mission returning from Jool, but I'd not accounted for the fuel required to enter back into Kerbon orbit, so the vehicle flashed by Kerbin at about 6km/s as I remember. The option I took was to send a rescue vehicle that was already in Minmus orbit, attached to a station there and had been used to transfer fuel to outgoing craft from the station, using the claw at its front.

I had to make an intercept with it as it passed beyond Minmus' orbit at high speed, grab it and then transfer any fuel that was left in it to the Jool vehicle, then adjust its course to have that rendezvous with Kerbin.

Intercept course

 

The two ships.

 

[ArmchairPhysicist]

16 hours ago, Enorats said:

Wait, how is it possible to botch a munar insertion like that? Do you mean you botched the insertion burn and either burned the wrong way or didn't have enough delta-v to achieve orbit (leading to the Mun slingshotting you out of SoI), or do you mean you missed the Mun entirely? Either seems rather unlikely to me, unless you're playing without some sort of delta-v calculator and had no idea what your ship could handle I guess.

I think the closest I've come was a no revert save where I was sending my first lunar mission of the career to a new mod's moon (Iota). I swung in close and was intending to combine my insertion and landing burn but came in too low. I hadn't mapped the unfamiliar moon's topography with ScanSat before so I didn't anticipate a giant mountain right at my periapsis. Noticed it just as I came out of time warp, oriented radial plus and burned.. then impacted the surface about 5 seconds later at greater than orbital velocity. Lost the engine and entire lower half of the craft, but the kerbals all survived in a command pod with no delta-v at all. They had to be rescued from an oddball orbit, but still within Kerbin's SoI.

I botched it by this. 

 

My munar missions are as such (yes they have problems, but I was working on low level parts, no multi person landers or docking).

My Munshot MK1 is a four stage heavy/super heavy lift class. It's a bit overkill and difficult but it works and it's fun.

It has 

1 Solid fuel booster stage. 8 kickbacks mounted radially.

2 A skipper running off of 3 rockomax x200-32s.

3 A lander powered by a swivel and a FL-T800

4 The command pod. The first pod mounted above a science lab and a service bay with sciency stuff.

 

Mission. 

The boosters and skipper fire simultaneously. Boosters carry it up to orbit altitude. Once I get to the apoapsis I fire my skipper again to circularize my orbit and extend my trajectory to just inside the muns orbit.

Then I warp until i intercept the mun. This is where things go wrong. If I get lazy and warp to much I run the risk of slingshoting into a kerbol orbit. RIP Jeb. But this only cal happen if I go to intercept behind the mun and not in front.

Once I enter the muns soi I use my skipper to enter a stable orbit, pick a landing site, burn retrograde to turn my munshot into ballistic missile *cough cough* I mean a lander. At this point my second stage is empty, so it gets jettisoned into the Mun, screw the environment. I use either my swivel or RCS to land. 

Yay mun. Do science, plant flag. 

If I did it right, I still have 3/4 of fuel left. Plus enough hydrazine to reach escape velocity. I take off, or if I landed wrong and bounced, I use the crater as a launch ramp. 

I exit munar orbit using my thrusters (RCS preferably), enter kerbin orbit, set myself to as low an orbit as possible.

Burn remaining fuel, areobreak, then land.

I plan on starting a pure career play through today. Can't use infinite electricity when I forget to put solar panels in a place pointing towards the sun (long story) and can't revert when a launch goes wrong. Should be fun.

[magnemoe]

I had one event like this, issue was power out because I did experiments while in shadow so I missed the orbital injection.
But as I had 3km/s Dv as you will on an Mun landing and return I was able to do an burn to keep inside Kerbin SOI, then lower pe to get an landing. 

Now if this low budget orbital mission like your first mun missions and not an landing you would have problems

[Enorats]

Ah. So you timewarp past the insertion burn and end up getting a slingshot instead. You can avoid that by simply clicking that part of the orbit and hitting "Warp here". Kerbal Alarm Clock is also an option, or Mechjeb's automated flying (I normally let it warp to the node then fly myself).

You mentioned it was low tech, but you'd likely get far better performance with a different engine on that lander. Swivels are mostly for 1.25m booster stages and are pretty inefficient in space compared to most alternatives. If you're not doing any docking RCS is pretty pointless too. RCS is horribly inefficient, if I'm not docking I generally don't even take monopropellant or RCS thrusters.

[JoeNapalm]

 

In Anand's case, it was a freak TIE fighter replica christening accident. 

On a wild hare I built a functional TIE fighter and wanted to test it out. As this was pre-Career Mode, there was no reason whatsoever not to use whatever booster I had laying around, so I mounted on top of an overbuilt Mainsail lifting platform. During the process of circularizing the orbit, I hit something...

I know, I know -- this is "impossible" due to the vastness of space and the relative velocities etc etc etc...but in my first save I always circularized at 100Km, tended to massively overbuild so I always had big lift stages still attached that I decoupled once I was there, and always had "infinite debris" enabled. As I was near the very end of my burn, the relative velocity to my massive cloud of Kessler Syndrome was quite low.

It was a one-in-a-million event, but that's cold comfort for Anand's remaining clones.

Anyway, long story short, the TIE fighter had (by definition) twin Ion engines, and could have recovered from a massively botched insertion -- except when I hit the debris, it damaged the TIE fighter to the point of being inoperable and also broke my coupling with the Mainsail lift stage -- inertia kept the TIE fighter pinned to the top of the still accelerating booster until all the fuel was expended...which, being a scale TIE fighter replica on top of a huge heavy lifter, was rather a LOT of extra fuel.

By the time the booster finally ran out of gas, poor Anand was in deep Kerbol orbit, with a single, off-axis ion engine that could only spin him around and around like a top.

That kept him entertained for months, and I did stock the rescue drone with comic books...but poor little guy was left out there for all eternity.

*Shakes fist at the uncaring Kraken*

 

-Jn-

[LoSBoL]

I Guess you need to be a @Physics Student  to do it with a Retrogade orbit

 

 

[Leafbaron]

Correct me if I'm wrong but doing a free return trajectory would mean you capture or not capture on the leading face of the body rather than intercepting on the trailing edge. Where capturing would put one in a retrograde orbit of said body. Additionally if one does not capture, the intercept would decrease your orbital velocity relative to Kerbin i.e. ensuring you "fall" back to Kerbin rather than gaining additional velocity from the intercept and potentially being slung outside the SOI of Kerbin. Regardless, my intercepts with the Mun typically happen at the Apoapsis of my orbit anyways and therefore any velocity received from the intercept is not enough to do anything to my orbit except possibly raise my perikee slightly. 

[Enorats]

Yeah, that's about how it works. If your intercept occurs on the far side of the Mun then you'll end up getting a gravity assist to a much higher orbit. If you come in on the inside of the Mun's orbit you'll end up in a lower elliptical orbit instead, possibly even dipping into Kerbin's atmosphere.