Security devices for the Orion CEV

The pretention is not that the suggestions below actually are fit. They may be correct but impossible to implement, they may cause more risks than they bring security... But, many such suggestions need to be made to pick out the final usable ones. More important maybe is the fact that an erroneous idea can be the seed for somebody else finding something right.

Sideways splashdown

The idea is that a little reserve parachute can be located on the side of the capsule, with a long wire and a strong mortar. Should more than one main parachute fail, the reserve parachute can be fired. The long wire and the strong mortar load ensure that it circles around the failed parachutes and opens above them. The fact the reserve parachute is latched to the side of the vessel increases the chances that it does not interfere with the main parachutes but also it makes that the capsule does not make a frontal splashdown in the water with its almost flat bottom heat shield. It will penetrate the water with an angle and plunge more deeply, with less brake force. This is expected to compensate for the higher fall speed.

Actually, the sideways splashdown has already been used by the NASA, for the Gemini capsules. At first the main parachute opens while latched to the top of the capsule, then a cable on the side is released to get the capsule on its side (one astronaut was hurt during this maneuver):

Dig the water

Here too, what if, due to partial parachute failure, the descent speed is too high and a flat contact with the water surface is dangerous?

The initial idea was to fire a mortar shell in the water short before contact. The capsule then plunges, either in the hole of water created by the mortar shell, or in the cone of rising water short afterwards.

A less explosive approach is to use solid rockets, with their blast directed towards the water and their trust vector directed towards the center of mass of the capsule. The aim is not to brake the fall but to dig holes in the water with the hot gas blow of the rockets. That way the capsule does not hit a flat surface but a cheese with holes acting as virtual airbags and ways for the water to escape.

The third approach is to have rods deploy below the capsule, either from the sides or from below the heatshield, with scoops at their ends. The scoops don't need to have a lot of surface but they probably need to have a hydrodynamic shape that prevents the capsule from tilting. Some of the water is pressed aside and the path into the water is prepared for the fast falling capsule. (The scoops can be made such that they fold or splinter partially apart when they hit ground. The harder the ground, the more the scoops are meant to fold back or splinter. The rods will push into the ground like nails. This will lengthen the brake distance, though I don't see this do better than the airbags intended for landing on ground.) The picture below shows such rod and scoop atop a Trident missile, meant to excavate the air at supersonic speed:

Maybe the solution on the safest side would be to shape and strengthen the airbags in such way that they are fit to push the water aside during a fast fall into water.

A dream would be a hedgehog of long telescopic rods and scoops deploying in all directions around the capsule. Maybe there would be space left to transport one astronaut... Another mad idea would be to add to the capsule one or more robotic arms, a downsized version of the Space Shuttle's arm, behind trap doors in the flank. Such a telemanipulation device would probably be helpful in Space, ease to work of the astronauts and be a factor of security in many emergency situations. During a too fast descent towards water, maybe the robotic arm(s) can deploy to hold and control a scoop in the most appropriate direction below the capsule?

Bail out

Many events can lead to a bailout: insufficient open parachute surface, the airbags inflating incorrectly while they are mandatory, the capsule turning into a fireball... No precise scenario can be established, so several ways of escape must be available and the best judgment of the astronauts must be trusted:

Both the side hatch and the top hatch must be available for emergency escapes.

The astronauts must have both individual parachutes and the ability to hook to one or more parachutes of the capsule and release them from the capsule to escape. Hence each parachute of the capsule must have a different color and the ropes of each parachute must have the same color as the canopy.

The individual parachutes must be immediately openable by hooking a static line somewhere. The static line of an unconscious astronaut must be operable by other astronauts.

The individual parachutes must be openable by a rip chord and allow the astronauts to float away from the capsule before they decide to open the parachute.

The pilot parachute of an astronaut's individual parachute system should be controllable, for example to lift the astronaut along another parachute's rope. The main parachute should be extractable by a rip chord if the pilot parachute gets inoperable.

The capsule's parachutes must also be operable by hand, by an astronaut emerging out of the top hatch.

Each astronaut should have a knife, to be able to cut parachute ropes.

At least one fireproof reserve parachute must be available on top of the capsule, possibly with a very long rope and the ability to fire it sideways, bypassing possibly failed main parachutes. That parachute should be either an annular parachute or a ballute, which decreases the risk of an astronaut getting stuck inside it.

The astronauts' suits and parachute pack must be fire-resistant for at least a short while.

Linked samara decelerator

In the event everything seems to fail, or to slow down the capsule once the astronauts bailed out, maybe a samara decelerator can be used; either a detachable side surface of the capsule or a foldable wing, together with a long rope, to create a wide virtual lifting surface above the capsule, by the little wing circling at high speed above the capsule. If the rope is long enough and the wing is leightweight, the increase of g force due to the rotation should be manageable by the astronauts and allow a bailout. Maybe a safe landing on water is possible.

Links

Crew Impact Attenuation Testing

Eric Brasseur - June 23 2009