Flight Question Earth reentry with a capsule style ship

[Iberville]

For more advanced players than me, I have a question about earth rentry with spaceship like Gemini, SpaceX Dragon, Orion, etc...
I am new to Orbiter but can now easily reach Orbit with those ships, aligned my plane, dock, but I am not sure if my reentry procedures are realistic or accurate:

- For reentry, I roughly wait to be near Australia and retroburn until me orbit reach somewhere is the ocean. I then just let my capsule drop in retrograde (but I shut down the retrograde button when I reach 100km and less) and when I reach like 5 km from the surface, I deploy the parachutes and It's done.

- It works, but would I juste burn up if I had a more realistic ships like DG IV? Is there an actual better way of coming back to earth? Or any tutorials for that king of ships?

Thank you!

 

[N_Molson]

To get a more-or-less realistic angle :

1) Set your Apoapsis between 200-300 kilometers
2) When you're at Apoapsis, fire your thrusters retrograde until the Periapsis is between 30-60 kilometers (depends how much lift you capsule can generate).
3) If you exceed 9Gs for more than ten seconds or so, the crew is dead. In general, the crew will die from G-Force before the heat shield breaks up.

Oh and to track the G-Force, take the Acceleration value in the Surface MFD and divide it by ten (9.81 in fact). So -100 m/s² = more or less 10G : that's too much, the crew is going to die unless the value quickly drops !

Here's the exemple of Apollo 7 Earth orbital reentry, it peaks at 3.5 G :

 

[Thorton]

3) If you exceed 9Gs for more than ten seconds or so, the crew is dead.

It is not true at all. First spacecrafts like Vostok had G-force ~10+G during half minute or so and nobody died. In fact, 9G is normal overload for Souyz ballistic reentry and peak lasts more than 10 seconds too.
Also in Soyuz 18-1 crew had 21G for few seconds during reentry.

 

[Mantis]

Also in Soyuz 18-1 crew had 21G for few seconds during reentry.

Yikes! I'll bet those guys were a little unsteady on their feet when they landed!

 

[RisingFury]

3) If you exceed 9Gs for more than ten seconds or so, the crew is dead. In general, the crew will die from G-Force before the heat shield breaks up.

Well... not really.

Vertical G-forces are difficult to deal with, but horizontal ones are easier. Depends on the orientation of astronauts in the capsule... if they're sitting so that their backs face the shield, they'll be able to withstand much more G's then if they were facing feet first (or head first) towards the shield.

 

[Artlav]

Here are first-person accounts of that flight, what they called the third suborbital:
http://www.novosti-kosmonavtiki.ru/content/numbers/209/42.shtml
http://epizodsspace.narod.ru/bibl/rebrov/kosm_kat/15.html

Unfortunately, i don't think i can translate it good enough, but maybe someone would volunteer.

In short, they were more concerned about landing in China and parachutes failing than the G forces, and apparently suffered no injuries whatsoever.

 

[N_Molson]

Cosmonauts are well-kown for their extreme endurance

From what I can read from Wikipedia, after the reentry with that 21G peak, Lazarev & Klimuk, fearing they landed in China, burned the papers about the experiments scheduled for the mission. Also they had to wait for the recovery teams about 24 hours by -7° (19F), in altitude. Really impressive. Looks like Lazarev was in some way injured however (hardly surprising) :

"Initial Soviet reports stated the men had suffered no ill effects from their flight. [ame="http://en.wikipedia.org/wiki/Vladimir_Shatalov"]Vladimir Shatalov[/ame], the Director of Cosmonaut Training, reported they were fit to fly another mission. However, subsequent reports claimed that Lazarev was injured by the high acceleration of re-entry."

But still, I think that it's better trying to stay under 9G while practicing re-entry with a capsule that produces lift. For "passive" capsules like Vostok, Voskhod or Soyuz in ballistic-reentry mode, that's another story, you don't have any control anyway.

 

[Mantis]

In terms of doing successful capsule re-entries with Orbiter, I've got the hang of getting the vehicles down successfully BUT may aim really sucks. I never seem to manage to land on the spot that I wanted to land! Any tips/pointers/suggestions? I realize that it will probably be at least somewhat different for each spacecraft and different if you're doing a direct descent (lunar return) vs. a regular descent from orbit.

 

[N_Molson]

[ame="http://www.orbithangar.com/searchid.php?ID=2139"]Aerobrake MFD[/ame] might help you, though I'm unfamiliar with it.

Aiming a precise spot on the ground manually is very difficult and requires a lot of practice !