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Space Shuttle Reentry


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Hey Guys,

So, my kind of favourite Orbiter right now is the space shuttle. After I found some good ones in the internet that fly reasonably well to orbit, I have problems reentering Kerbin. So I have a few questions.

I'm reentering Kerbin at about 2500-3000 Km/h. Where should I do a manuever node to safely land at the "Main Base", you know, the rollway. I'm always missing the rollway for about a few hundred kilometers every time (or I crash).

Is there a kOs Script you guys have that'll do something like that? Because I believe the whole landing thing is complicated.

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3 hours ago, Luca2806 said:

Where should I do a manuever node to safely land at the "Main Base", you know, the rollway. I'm always missing the rollway for about a few hundred kilometers every time (or I crash).

Well, without flying the same craft ourselves(at the very least to see a picture) there is not much we can say. Just the usual "roughly at the wastelands". But is not just about where you start the descent, you need to control your glide rate, do this by pitching up(undershooting) or down(overshooting). Helps if you have a waypoint of KSC to orient yourself, but there is also the experience telling that you should be at X altitude and Y speed when passing Z landmark and you only get experience by doing it.

 

3 hours ago, Luca2806 said:

...the whole landing thing is complicated.

In fact the whole Shuttle/Spaceplane thing is. But asking for help is a tested and true way to find it .

 

 

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4 hours ago, Spricigo said:

Well, without flying the same craft ourselves(at the very least to see a picture) there is not much we can say. Just the usual "roughly at the wastelands". But is not just about where you start the descent, you need to control your glide rate, do this by pitching up(undershooting) or down(overshooting). Helps if you have a waypoint of KSC to orient yourself, but there is also the experience telling that you should be at X altitude and Y speed when passing Z landmark and you only get experience by doing it.

 

In fact the whole Shuttle/Spaceplane thing is. But asking for help is a tested and true way to find it .

 

 

Ok, I've tried to upload a screenshot for you but it's not working somehow :/

But what I can say is that my Periapsis is 198km and my Apoapsis 206km above Kerbin and I have 630 m/s DV.

https://wiki.kerbalspaceprogram.com/wiki/File:TinyKerbin.png   Do you mean I should go down on the desert on the right? If yes, where exactly? The green Island next to it is the island where the Space Center is located (+ the rollway)

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You need to do your deorbit burn on the opposite side of the planet to where you want to end up- on Kerbin it’s over the ”Badlands”. The only way to judge these things is by trying it- try a periapsis of 35km over KSC and see where you end up landing, then move it higher if you land too short or lower if you overshoot. You can also change your angle of attack when re-entering to generate more or less drag which will affect where you land as well; a higher angle of attack generates more drag so will slow you down more.

You should aim to overshoot slightly as it’s possible to dump excess altitude by making a series of spiral turns before landing, but you can’t get extra altitude if you don’t have enough unless you have engines and fuel to run them.

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The screenshot need to be posted in a  external site like imgur and posted as a link there. (I think some other restrictions for new posters may also exist but don't know for sure)

5 hours ago, Luca2806 said:

 Do you mean I should go down on the desert on the right? If yes, where exactly?

Well, the "exactly" is the trick part. Depends on a lot of things. In some circumstances you can do it the 'most ineffective way and get away with this, in others the craft explodes in the slightest deviation.

I indeed have a few spaceplanes that can do the retroburn above that desert and land nicely at the runaway (no overheating or overshooting problems), but they are small, can hold high AoA and are coming from very low orbits. Your situation is different in at least one aspect: orbital height and i suspect that is not the only one.

@jimmymcgoochie suggests to do the burn the other side of the planet and drop the periapsis to 35km. That approach, which is the usual advice,  makes easy to avoid overheating problems but also kind of easy to mess with landing at the target location (rather land intact 100km away from KSC then crash catastrophically into the runaway). I personally don't like it very much (that's is why i don't design my spaceplanes to need it) but it works for a wide  range of crafts and situations and  is reasonably safe, thus a good approach to try first.

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Thanks Guys for the good advises.

even tough I keep on crashing because I lose control in the dense part of the atmosphere, I am now able to see the KSC. So I just need some practice and it will hopefully be a success :D

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3 hours ago, Luca2806 said:

even tough I keep on crashing because I lose control in the dense part of the atmosphere, I am now able to see the KSC. So I just need some practice and it will hopefully be a success :D

Don't want to burst your bubble but it maybe the case of lack of practice if it is the "I move too far away from prograde and lose control" but if it is the "no matter how much I try it just point back to where it comes from" then you have a more serious problem, a design problem.

Even then, if you can still go back to when you launched it, there is no shame to just attach some parachutes to get the mission at the hand done and after that try to fix the flipping problem.

Also, go back to where you got it and see if the designer recommended some procedure for reentry. It's often the case that moving some remaining fuel to better balance the CoM/CoL relationship before reentry is required.

 

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15 minutes ago, Spricigo said:

Don't want to burst your bubble but it maybe the case of lack of practice if it is the "I move too far away from prograde and lose control" but if it is the "no matter how much I try it just point back to where it comes from" then you have a more serious problem, a design problem.

Even then, if you can still go back to when you launched it, there is no shame to just attach some parachutes to get the mission at the hand done and after that try to fix the flipping problem.

Also, go back to where you got it and see if the designer recommended some procedure for reentry. It's often the case that moving some remaining fuel to better balance the CoM/CoL relationship before reentry is required.

 

Yeah it definitely is the lack of practice. I only have like 80 hours ingame. The whole CoM/CoL thing is also complicated for me although I sometimes use Kerbal Engineer Redux. Do you know a mod by the way for 1.9.1 that makes the Space Shuttle Built easier? Or even a mod that is built around a Space Shuttle (or Buran Energija)?

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Shuttles are a tremendous design challenge. Remember to have your Com a little further forward than halfway on your craft before you ever put in your fuel or payload. Then you have to fill it up with fuel and monopropellant and make sure it's still generally in the center, and again once you've thrown in the payload. Then after that, it doesn't hurt to do some tests by taking out the payload and like 95% of the fuel and seeing if you can glide the thing safely to the ground and land from supersonic speeds. If all of this works out, then try launching it as intended and see how it goes. As far as flying it on reentry? I found a cool video on youtube that describes how the real shuttle computer and commanders used to do it. It's really interesting stuff. 

 

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5 hours ago, Luca2806 said:

Yeah it definitely is the lack of practice. I only have like 80 hours ingame. The whole CoM/CoL thing is also complicated for me although I sometimes use Kerbal Engineer Redux. Do you know a mod by the way for 1.9.1 that makes the Space Shuttle Built easier? Or even a mod that is built around a Space Shuttle (or Buran Energija)?

I'm not familiar with any particular shuttle parts mod. But for actually placing the parts in the right place there is quite a few:

BTW, there is any mod with open license you didn't adopted yet, @linuxgurugamer?

Not that I'm complaining, quite the contrary.

 

 

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5 hours ago, James M said:

Shuttles are a tremendous design challenge. Remember to have your Com a little further forward than halfway on your craft before you ever put in your fuel or payload. Then you have to fill it up with fuel and monopropellant and make sure it's still generally in the center, and again once you've thrown in the payload. Then after that, it doesn't hurt to do some tests by taking out the payload and like 95% of the fuel and seeing if you can glide the thing safely to the ground and land from supersonic speeds. If all of this works out, then try launching it as intended and see how it goes. As far as flying it on reentry? I found a cool video on youtube that describes how the real shuttle computer and commanders used to do it. It's really interesting stuff. 

 

Thanks I’ll take a look into that and write that done.

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4 hours ago, Spricigo said:

I'm not familiar with any particular shuttle parts mod. But for actually placing the parts in the right place there is quite a few:

BTW, there is any mod with open license you didn't adopted yet, @linuxgurugamer?

Not that I'm complaining, quite the contrary.

 

 

Thanks a lot I’ll download it ASAP.

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