Crewed capsules

Crewed capsules

Crewed capsules are capsules that fly into space with a human crew. Three nations have successfully brought astronauts to space and returned them safely back to earth. These nations are Russia, the US, and China. At the moment, India is on its way to becoming the fourth nation to perform this engineering feat. Other nations have attempted or are working on their crewed capsules. 

Crewed capsules are required to have very high reliability to ensure the astronaut's safety during the flight. This often results in redundancy and backup systems. This can be seen in all subsystems of the capsules, including the parachute system. The various capsules have included this in different ways leading to different concepts. These can be found in the pages above. 

Launch escape systems

Having high reliability also means the crew need to be able to survive a failed launch, which leads to the inclusion of a launch escape system.  Launch escape systems are used to pull the astronauts away from the failing rocket. The system has been used in action two times on Soyuz T-10-1 and Soyuz MS-10. In both cases, the astronauts safely landed after the booster failed. An accidental test was done during the A-004 flight test of a Little Joe II rocket carrying an early version of the Apollo capsule. An unexpected roll caused the vehicle to break apart triggering the launch escape system. 

The activation of a launch escape system occurs relatively early in the flight; this means the capsule cannot use the atmosphere to slow down using air drag. Normally, the capsule uses some lift generating capabilities to slow down, this is not possible for a launch escape situation. The combination of high velocity and low altitude means the dynamic pressures are much higher. To ensure the parachute system can survive these conditions, tests are conducted. A more recent example of a launch escape test is the Falcon 9 launch escape test seen in the video on the right. Most launch escape systems use the same parachute system they would use during a regular landing. These launchers usually have a  Launch Escape Tower on them with solid rocket motors to pull the capsule away from the failing rocket. Others have a pusher system to push the capsule away from danger.

Two notable exceptions are the Gemini capsule and the Space Shuttle. The Gemini capsule was the first US capsule to carry more than one person to orbit. Gemini was notable for not having a launch escape tower. Instead, the capsule had two ejection seats that could be used in case of emergency. This meant that the capsule had a redundant set of parachutes onboard that were never used. After deployment, a ballute would be deployed for stability when ejected above 7500 ft (or 2.29 km). The US Space shuttle also used an ejection seat system for the first couple of flights. For later flights, the Space Shuttle did not have ejection seats.

Falcon 9 in flight abort test