Space/Science — HabitableZone

Space/Science » in reply to Escape systems

Disagree about the CRV

The Crew Rescue Vehicle is actually the simplest and least expensive manned spacecraft designed to date. It was designed for one purpose - emergency evacuation for up to 7 people. It has some basic specs like the ability to stay on-station for a year or so, to fit into a Shuttle cargo bay, and to be easy to operate. The design I've seen has met those requirements admirably.

The systems on the CRV are very simple and inexpensive. For example, to reduce the need for hypergolic propellants (toxic, corrosive, and generally nasty), it uses a simple and inexpensive pressurized nitrogen system for attitude control thrusters. This system has been proven in space for decades. I've read they're looking at a solid rocket thruster for the deorbit engine, again for the purpose of simplicity, low cost, and long term storability. Solid rocket deorbit engines date back at least as far as the Mercury and Gemini missions.

The lifting body design has several desirable characteristics. One of them is a lot of internal volume for a given size. That makes for a compact vehicle that'll fit in a cargo bay. Even more important, a lifting body allows for significant cross range capabilities on reentry. If the crew ever did need to make an emergency evacuation due to a catastrophic fire or accident, they'd need to get on the ground as quickly as possible. Capsules don't have a lot of cross range capability, so there are many times when the crew might have to wait for one or more orbits before they'd be within range of a suitable landing zone. That's less likely to happen with a lifting body. It has the cross range capability to change its descent trajectory by hundreds of miles during reentry.

The parasail allows the vehicle to soft land almost anywhere there's a clearing a few hundred meters across. It doesn't require long runways, recovery fleets, or much else on the ground to allow for safe landing or recovery. The military has been experimenting with automatic parasail landing systems for years for precision airdrops. This isn't cutting edge stuff.

One of the most important characteristics of the CRV is that it doesn't require a pilot to operate. Even the Soyuz requires a substantial amount of training to operate. In the CRV, all the crew has to do is strap in, close the hatch, and press a button or two. The system is designed to fly itself all the way to the ground. This allows the crew to be made up of people like scientists instead of having to keep a pilot on board just for the escape system. It also allows for the possibility that the crew may be semi-incapacitated from things like smoke inhalation.

One thing people seem to be forgetting is that accidents happen to our launchers, too. Both the Soyuz and Shuttle programs have had accidents that led to lengthy groundings. What happens to a crew if the Shuttle or Soyuz is grounded for a year or two? What happens if both happen to have accidents at once? Don't say it can't happen because it already did - the Apollo 1 fire and the Soyuz 1 accident caused both manned programs to be grounded at the same time back in 1968. If it happened once, it can happen again.

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