Russian Manned Space Vehicle May Land With Rockets

The Narrative Fallacy writes "Russia's next-generation manned space vehicle may be equipped with thrusters to perform a precision landing on its return to Earth. Previous manned missions have landed on Earth using a parachute or, in the case of space shuttles, a pair of wings. Combined with retractable landing legs and a re-usable thermal protection system, the new system promises to enable not only a safe return to Earth, but also the possibility of performing multiple space missions with the same crew capsule. The spacecraft will fire its engines at an altitude of just 600-800m, as the capsule is streaking toward Earth after re-entering the atmosphere at the end of its mission. After a vertical descent, the precision landing would be initiated at the altitude of 30m above the surface. Last July, Korolev-based RKK Energia released the first drawings of a multi-purpose transport ship, known as the Advanced Crew Transportation System (ACTS), which, at the time, Russia had hoped to develop in co-operation with Europe. 'It was explained to us how it was supposed to work and, I think, from the technical point of view, there is no doubt that this concept would work,' says Christian Bank, the leading designer of manned space systems at EADS-Astrium in Bremen, Germany. However, the design of the spacecraft's crew capsule had raised eyebrows in some quarters, as it lacked a parachute — instead sporting a cluster of 12 soft-landing rockets, burning solid propellant. Inside Russia, the idea apparently has many detractors. During the formal defense of the project, one high-ranking official skeptical of the rocket-cushioned approach to landing reportedly used an unprintable expletive to describe what was going to happen to crew members unlucky enough to encounter a rocket engine failure a few seconds before touchdown."

Comments

Weight problems?

[eebra82]

In other words, they must think that adding that extra fuel weight (for landing) is worth the extra fuel weight that is needed to launch the rockets into space. After all, the landing fuel will cost them a lot of extra weight. I don't know how much extra it would be, but it doesn't sound like a good idea.

High-G landing?

[cdrguru]

Let's see, how fast might the ship being going when the landing system kicks in? Falling from orbit to the ground is going to produce a lot of velocity to bleed off in apparently a very short time. The shuttle uses both atmospheric braking and S-turns to bleed off velocity and still lands pretty darn fast.

It sounds like this just falls without a chute. I'm not going to do the math, but even if it is subsonic at 800m, you are going to have to brake like mad at the end. 10G braking? 20G doesn't sound like it would be outlandish. OK, so it is a short period of time and with solid-fuel rockets it is just one pulse. But it sounds like it would be ohe heck of a pulse.