Deorbit

[Danny Ramone]

na i definitely changed it back. I might try it without damage or with re-entry mfd and see what happens

 

[ar81]

hi:rofl:

Can you help me whit the reentry? I have read some tutorial but I have not understood a lot.

I want to know when do the "deorbit burn" and what are the "s-turns" an when i do it???


thank you

First, I think the right word is entry and not reentry, because you are not "entering again". NASA manuals use "Entry".

When you are in orbit, you can make your orbit smaller by firing retrograde. If you make it small enough, so periapsis touches atmosphere or planet surface, you are on your way down to the planet, you are deorbiting. So deorbit involves a retrograde burn.

If your angle of entry is too steep, you would burn, as you get into more dense atmosphere at high speed. So the trick is to make the entry not too steep. How much is steep? 1 or 1.5 degrees is too steep. So when you see all those fancy movies that show an entry of 30 degrees, you know this is Star Wars physics or vessels made with unobtanium, a fictional material that is quite resistent to anything (probably this is what Superman is made of :rofl.

If you have an atmosphere, the trajectory will not be linear, since you have aerobrake. Aerobrake MFD helps you to locate the point of impact.

During reentry you have an AoA or angle of attack. This angle is the angle between the direction of motion of your craft, and the direction of your nose.

S turns means that you move your vessel left and right, keeping your AoA constant and the direction of motion aligned with vessel simetry plane (it means rotating your craft around the direction of motion clockwise or counterclockwise). In the end as you rotate to one side and then the other, your trajectory as seen from above will be a long S shape.

S turns are useful to waste energy, so you do not overshoot your target base. Since holding your nose up causes lift, rotating sideways during S turns prevents that lift generated by aerobraking will bounce you back to space or to overshoot your target base.