[Challenge] Escape, but return

[Warringer]

Your challenge, should you choose to accept it, will be to build a rocket.

This rocket will have to enter orbit, orbit the Kearth once and then accelerate to escape velocity.

At reaching a distance of 10000km to Kearth, the rocket will turn back, enter an orbit and after one orbit around Kearth, return to the planet.

Kerbal Astronauts all over Kearth will cheer for you should you choose to accept this challenge.

This message will be shot into orbit with a faulty booster in ten seconds.

[Ice]

I can has cake now?

[fermun]

Challenge accepted, I have about 6 hours I can use to attempt this, checking every half hour or so. Since this is a really long mission to do properly, I'm going to attempt to burn my way there instead of using the most efficient path, I'll just turn up the throttle. As such I need a big ship.

Roc Heavy Lifter Mk. 4 on launch pad.

Apokee

Dawn again!

Perikee

Launch pad down there!

A bit past half way there.

10,000K

Turning around took a lot of work, but headed down again!

Passing 10,000K again. I burned a bunch more fuel to get the speed up because I realized it would take forever to get back down otherwise. Half a tank left.

Roughly looks like I should be headed for a high orbit, though it may take a hell of a retrograde burn to slow it down to keep from shooting off into space. Fuel will be tight.

Oh my, this does not look good. DROPPING FAST! TOO FAST! Not nearly enough fuel to slow this down.

Well, dropping down on the dark side.

Hit the dark side. Everyone dead.

[Ice]

^My god... That is awesome...

[Entropy]

Holy shit, that made it into orbit? Hats off to you.

[Supraluminal]

I'm giving this a shot right now, and I think I can pull it off. However, the 10,000km distance stipulation feels needlessly and arbitrarily far off - as long as you can orbit, then achieve escape velocity, you can get to any distance you want. It's just a matter of patience. Same goes for getting back; as long as you can slow yourself to below escape velocity, you'll drop back to the planet eventually.

There may be some challenge in managing your return trajectory at that distance so that you aren't headed straight for the ground at high speed, I guess. I don't think it's as much a physics issue as an instrumentation/control one, though, if I've correctly understood the crash course (pun intended) in orbital mechanics that this game has sent me through.

[fermun]

It is temperamental, but assuming you don't mess up switching stages and blow yourself up, it gets to orbit every time. If it starts acting up too badly, you can just cut all power, jettison a stage and start on the next. You have to fight it the whole way up, but proper piloting leaves you with a little bit more than 1 tank of fuel for each of the 4 engines on the 4th stage, whereas in that attempt I only had half a tank per engine. Each stage is just barely enough to accelerate so you hit orbit having only pulled 2 Gs acceleration the whole way up. If I had piloted it better and had more time, I think I could have done it.

[Supraluminal]

OK, I made it out to 10,000km and started my return flight last night, but I had to give up and go to bed at about 8,500km out. Trying again right now. I'm on my way out with a bit more fuel than last time, so it's off to a good start!

[Warringer]

I'm giving this a shot right now, and I think I can pull it off. However, the 10,000km distance stipulation feels needlessly and arbitrarily far off - as long as you can orbit, then achieve escape velocity, you can get to any distance you want.

True, but once there is going to be a moon, it may orbit Kearth quite a bit further out.

@fermun:

Nice work there, want to give it another try?

[Supraluminal]

Success! Total mission time of about 7hrs, 40mins. Many, many photos below:

My vehicle of choice. Manages about 7660m/s on a straight vertical burn.

Shortly after liftoff, the first stage of boosters is gone.

Burning into orbit.

Cruising across the dark side. It ended up being a pretty eccentric orbit; we're over 375km here.

Here we are crossing over the KSC, finishing up our first orbit.

Time to get out of here. Accelerating to escape velocity at periapsis.

Past 1000km, we're on our way! Even brought the second-to-last stage along with a tiny bit of fuel remaining, which I hadn't really planned on.

A bit over halfway there....

10,000km reached. Time to turn this pig around.

Alright, retrograde burn done, heading back at 500m/s to start with. It would have been much more efficient to simply drop back below escape velocity and let gravity do the rest of the work, but that would have taken foreeeeever.

Over halfway back!

<1000km to go. Here's where things start getting tricky.

One of many maneuvering burns made to end up in something like a stable orbit.

You may just barely be able to make out a few pixels of KSC on the coast near the horizon here.

Passing over KSC. It's not really visible, but you can recognize the landmass and confirm with the pink directional indicator (pointing just about straight down).

Apoapsis on the dark side.

That allowed me to plot my current orbit. Eccentric, but stable!

Passing directly 'under' KSC, as shown by the directional indicator. Halfway around!

Obligatory sunrise shot.

Periapsis after another burn to circularize at a lower altitude.

The new orbit. Pretty good!

Passing directly over KSC a second time. Alright, orbit done!

Time to park this thing. Hopefully we'll end up in the water on the other side of the KSC landmass.

Farewell, faithful steed! Jettisoning that stage after all we'd been through was actually kind of bittersweet, if you can believe it.

Hmm, that coastline's coming up pretty fast....

Welp, looks like it'll be a bump rather than a splash.

At least we'll have a nice view from this ridge!

Unfortunately the capsule clipped through the terrain on landing. Later on I rolled it around until it resurfaced for a better photo op, but this is exactly where touchdown occurred.

Stats!

Our intrepid Kerbalnauts at rest with a nice oceanside view.

Overall a fun challenge. I still think going all the way out to 10,000km was a little over the top, but in combination with the lack of a game-saving feature it did have the effect of ratcheting up the tension as I was managing my orbital insertion on the return!

So, is there a prize, or...?

[Zeroignite]

Truly epic. It's like the Magellanic voyage!

[DeCi]

Success! Total mission time of about 7hrs, 40mins. Many, many photos below:

My vehicle of choice. Manages about 7660m/s on a straight vertical burn.

Shortly after liftoff, the first stage of boosters is gone.

Burning into orbit.

Cruising across the dark side. It ended up being a pretty eccentric orbit; we're over 375km here.

Here we are crossing over the KSC, finishing up our first orbit.

Time to get out of here. Accelerating to escape velocity at periapsis.

Past 1000km, we're on our way! Even brought the second-to-last stage along with a tiny bit of fuel remaining, which I hadn't really planned on.

A bit over halfway there....

10,000km reached. Time to turn this pig around.

Alright, retrograde burn done, heading back at 500m/s to start with. It would have been much more efficient to simply drop back below escape velocity and let gravity do the rest of the work, but that would have taken foreeeeever.

Over halfway back!

<1000km to go. Here's where things start getting tricky.

One of many maneuvering burns made to end up in something like a stable orbit.

You may just barely be able to make out a few pixels of KSC on the coast near the horizon here.

Passing over KSC. It's not really visible, but you can recognize the landmass and confirm with the pink directional indicator (pointing just about straight down).

Apoapsis on the dark side.

That allowed me to plot my current orbit. Eccentric, but stable!

Passing directly 'under' KSC, as shown by the directional indicator. Halfway around!

Obligatory sunrise shot.

Periapsis after another burn to circularize at a lower altitude.

The new orbit. Pretty good!

Passing directly over KSC a second time. Alright, orbit done!

Time to park this thing. Hopefully we'll end up in the water on the other side of the KSC landmass.

Farewell, faithful steed! Jettisoning that stage after all we'd been through was actually kind of bittersweet, if you can believe it.

Hmm, that coastline's coming up pretty fast....

Welp, looks like it'll be a bump rather than a splash.

At least we'll have a nice view from this ridge!

Unfortunately the capsule clipped through the terrain on landing. Later on I rolled it around until it resurfaced for a better photo op, but this is exactly where touchdown occurred.

Stats!

Our intrepid Kerbalnauts at rest with a nice oceanside view.

Overall a fun challenge. I still think going all the way out to 10,000km was a little over the top, but in combination with the lack of a game-saving feature it did have the effect of ratcheting up the tension as I was managing my orbital insertion on the return!

So, is there a prize, or...?

U win my respect thatd for sure. Great story!

Next time make a youtube vid with some voiceover!

[Expresate]

U win my respect thatd for sure. Great story!

Next time make a youtube vid with some voiceover!

A 7 hour long Youtube Video with a 7 hour long voiceover?

[Ice]

A 7 hour long Youtube Video with a 7 hour long voiceover?

Like a boss.

[Supraluminal]

Haha, yeah, a full-length video of that trip would be incredibly boring. 5% coverage of actual maneuvers, 95% me trying to fill dead air with awkward jokes and personal anecdotes. Or watching me answer emails and debug websites while the game runs minimized in the background, to be completely realistic.

If/when I try something like this again (because I'm definitely not doing exactly this again!), maybe I'll see about getting Fraps or some other video recorder set up. Assuming they can easily be turned on/off during play I could do a highlights reel or something I suppose.

[SiLo]

Why did it take so long to get to 10K? I've been running it for about 48 minutes and I'm at 25K Km already, The engine hasn't been on for about 15 minutes either so it could be going quite a lot further. Done with two engines, and two fuel pods, can't remember what they are called but it's the round ones with black holes in (lol). First engine was a futuristic one with ridiculous thrust and the second was the ion engine. Still got about 3/4 of a tank of fuel left too!

[DeCi]

Why did it take so long to get to 10K? I've been running it for about 48 minutes and I'm at 25K Km already, The engine hasn't been on for about 15 minutes either so it could be going quite a lot further. Done with two engines, and two fuel pods, can't remember what they are called but it's the round ones with black holes in (lol). First engine was a futuristic one with ridiculous thrust and the second was the ion engine. Still got about 3/4 of a tank of fuel left too!

Getting to 10 km. shudnt take more than 3 mins.

otherwise your doing something really wrong in your design.

[Supraluminal]

Why did it take so long to get to 10K? I've been running it for about 48 minutes and I'm at 25K Km already, The engine hasn't been on for about 15 minutes either so it could be going quite a lot further. Done with two engines, and two fuel pods, can't remember what they are called but it's the round ones with black holes in (lol). First engine was a futuristic one with ridiculous thrust and the second was the ion engine. Still got about 3/4 of a tank of fuel left too!

Because I did it with all stock parts. What's the top speed at vertical burnout on your ship? The one I used can manage 7661m/s. I suspect yours would be much, much higher.

Getting to 10 km. shudnt take more than 3 mins.

otherwise your doing something really wrong in your design.

I think you misread - he wrote '10K,' meaning 10,000km.

[DeCi]

Because I did it with all stock parts. What's the top speed at vertical burnout on your ship? The one I used can manage 7661m/s. I suspect yours would be much, much higher.

I think you misread - he wrote '10K,' meaning 10,000km.

My mistake. Move along! this is not the Post your looking for, :

[SiLo]

Haha yeah I meant 10,000 Km. Yeah I got it to about 12000 ms/s but I wasn't burning the whole time and had loads more fuel left.

[tjrieves]

Supraluminal, could you upload your ship? That thing looks amazing. Also, I'm too busy/lazy to build my own ship right now.

[Heimdall]

Success! Total mission time of about 7hrs, 40mins. Many, many photos below:

That allowed me to plot my current orbit. Eccentric, but stable!

The new orbit. Pretty good!

So, is there a prize, or...?

+1 internet

very impressive, you have the guts of a true kerbanaut.

Also, what's the program you used in those pics ? (it will be mine, oh yes, it will be mine !)

[Supraluminal]

Supraluminal, could you upload your ship? That thing looks amazing. Also, I'm too busy/lazy to build my own ship right now.

Sure! It's attached to this post.

Beware, it's a little finicky. At a couple of points it may try to pitch/yaw/roll or just generally wobble on you, but with SAS on it should be easy enough to keep under control if you babysit it during launch. Also, most importantly, give the initial liquid-fueled booster stage enough time to fall away before you ignite the second stack of liquid engines and solid boosters or the whole thing will blow up. I recommend 4 or 5 seconds of delay. (This is the stage 7 -> 6 -> 5 transition according to the in-game stage numbers.) This is also the point where you'll get the worst yaw imbalance, so be prepared to lean on your D key while the SRBs are firing. That's the last hurdle, though; once they drop off you're in the clear!

[Supraluminal]

+1 internet

very impressive, you have the guts of a true kerbanaut.

Also, what's the program you used in those pics ? (it will be mine, oh yes, it will be mine !)

Thanks!

The program is cjameshuff's orbit calculator. Many thanks to him for creating such a useful tool! His table of circular orbit speeds and periods is great, but the calculator is a real step up in flexibility, especially since it'll tell you if your elliptical orbit is going to crash into the planet or not.

[plazmaXIII]

just attempted this. reached 1000,000m and managed to slow down past escape velocity and set a hohmann transfer orbit back to earth.

however, my eagerness to get back led to me boosting to try and get back faster, resulting in me overshooting, and now im stuck in orbit.

fail . . .