How do i NOT blow up in the atmosphere?

[Clockwork13]

For the past few days, I have been stuck not knowing how to make a successful suborbital flight. First issue is how my parts keep overheating. I tried using a heatshield and even tried covering my ship in small radiators, and even just tried taking all my science to the pod and let all my other experiments get blown off, which actually worked. Then I faced another problem. All the way until i was 500 meters above the ground (i happened to be in a highland so it was hard to tell), it didn't once say my parachutes were safe to deploy. When i was only 500 meters above the ground, i just deployed anyway since i had no other choice, and sure enough they got destroyed. I don't even have any idea how do get to the ground safely. I've considered keeping my boosters to help me slow down in the atmosphere, although I'm not sure if that would help.

Edited June 27, 2015 by Clockwork13

[sal_vager]

Hi Clockwork13, it's hard to know what's going on just from that, but you should be able to re-enter without much trouble if you set your periapsis to about 30km.

You'll slow down quickly enough to avoid too much atmospheric heating, too high and you'll be super sonic for too long and risk overheating, too much lower and you can punch through the atmosphere without losing enough speed to safely open the chutes.

The new default for chutes is to open at 1000m and 0.04 pressure, craft launched before the update may still have the lower values though, so adjust them accordingly.

If your Physics.cfg is old you may also have incorrect values for heat, so rename it Physics.old so KSP makes a new one.

[rofltehcat]

Ok, I understand it this is basically your first time orbiting? Then you're probably in an altitude of 70-100 km and at a speed of 2300+ m/s. To not burn up you need to lose some speed but not too much speed because that would make you drop into the atmosphere too steep.

I suggest first doing retrograde (backwards) burns near the AP and PE positions of your orbit until the other one is just around 75 km (if you're lower, like 65 km or so it isn't a problem in this case either but below 70 km you slow down because of the atmosphere). Then do another short retrograde burn to bring one part of your orbit to around 50 km altitude. Fast-forward until you enter the atmosphere (70 km altitude), then slow down the warp a bit (highest setting may make you explode). You will start losing speed because of the air friction and there will be a lot of heat but you should be fine. If you can, point the engine forward as an additional heat shield.

If this doesn't work you'll probably have to experiment a bit with your reentry angle.

Edit: you can also try the 30 km altitude suggested while I was typing this. You'll probably just have to try it yourself. If you go too high it might take a long time for you to slow down enough but I find it to be a bit safer.

Edited June 26, 2015 by rofltehcat

[Kryxal]

A pod can survive a landing at sea level (or near to it), but the deorbit is tricky ... till you get drogue chutes, it's going to be tough to land stuff.

[Clockwork13]

Hi Clockwork13, it's hard to know what's going on just from that, but you should be able to re-enter without much trouble if you set your periapsis to about 30km.

You'll slow down quickly enough to avoid too much atmospheric heating, too high and you'll be super sonic for too long and risk overheating, too much lower and you can punch through the atmosphere without losing enough speed to safely open the chutes.

The new default for chutes is to open at 1000m and 0.04 pressure, craft launched before the update may still have the lower values though, so adjust them accordingly.

If your Physics.cfg is old you may also have incorrect values for heat, so rename it Physics.old so KSP makes a new one.

I'm not orbiting though, i'm just going straight down which might be a problem.

Edit: fixed typo in main post

Edited June 26, 2015 by Clockwork13

[rofltehcat]

Straight down is your problem. To go into space (and stay there for a while) you actually need more sideways speed than vertical speed. If you are currently falling towards Kerbin, are very high, and still have some fuel left you can try firing radial+ (sideways outwards) and try to get into an elliptical orbit. This can either put you into an elliptical orbit if you are very high or at least give you a shallower entry trajectory.

[Clockwork13]

Straight down is your problem. To go into space (and stay there for a while) you actually need more sideways speed than vertical speed. If you are currently falling towards Kerbin, are very high, and still have some fuel left you can try firing radial+ (sideways outwards) and try to get into an elliptical orbit. This can either put you into an elliptical orbit if you are very high or at least give you a shallower entry trajectory.

The basic craft i designed isn't meant for orbiting though. Making it an orbiter probably wouldn't be to difficult, but I'm kind of low on funds. Would using the main booster to slow myself down work?

EDIT: my booster i dont think has a gimbal. (should go check)

Edited June 26, 2015 by Clockwork13

[rofltehcat]

Yeah in theory firing the booster on the way down can work as well but it'll be riskier and less effective than firing radially.

[Clockwork13]

Yeah in theory firing the booster on the way down can work as well but it'll be riskier and less effective than firing radially.

True. I'll try it though when i get on

[imaspacestation]

The basic craft i designed isn't meant for orbiting though.

It doesn't really matter, you don't have to complete an orbit, you just have to have your trajectory at a shallow enough angle so that you aren't coming in so steep during re-entry.

Are you saying your craft does not have enough fuel to reach 70km+ unless you fire it straight up?

[Clockwork13]

It doesn't really matter, you don't have to complete an orbit, you just have to have your trajectory at a shallow enough angle so that you aren't coming in so steep during re-entry.

Are you saying your craft does not have enough fuel to reach 70km+ unless you fire it straight up?

It has enough fuel to go up to 4000 km above kerbin, i just dont think it has a gimbal to turn it though (checking right now)

[imaspacestation]

I think all LF Engines have gimbals, even just 2 degrees? But if you are using entirely only SRBs then Jebediah commends you, and you can use Reaction Wheels instead to change your pitch. And RCS. And winglets. And tiny little engines that do have gimbals.

[Reactordrone]

If you're going straight up for a suborbital contract you need to keep the altitude in check, anything over 215km is likely to kill an unshielded pod on reentry 9about 450km if you're using shields). If you're using solids and don't have the ability to throttle you can aim for a long ballistic flightpath so that your entry angle is shallower.

ETA- if you have airbrakes unlocked use as many of then as you can instead of shields, they're lighter than a heatshield and going slower is more effective than using high temperature parts.

Edited June 26, 2015 by Reactordrone

[Clockwork13]

Changed the rocket a little bit and tried to put it in orbit, although ended up not having enough fuel for that, although I probably would have if I was orbiting a bit lower. I was able to safely land though due to a softer approach into the atmosphere.