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The VERY dangerous Orion's TPS
ALL past and present capsules, shuttles and probes like Apollo, Soyuz, etc. was/are built with their TPS (Thermal Protection System) FIRMLY JOINED to the vehicle's main body, but the Orion's design has an "innovation": its TPS is NOT "firmly joined" to the capsule since it will be jettisoned after reentry to inflate the underside airbags for a soft landing on soil.
That seems a great idea to have (both) sea and soil soft landings (near the KSC) but, in case of (hardware or software) explosive bolts flaw, the Orion's astronauts may face a dramatic contingency like this:
The Orion is detached from its Service Module but its thermal shield remains joined to the SM so the Orion may have (or not) a sufficient reserve of oxygen, water and energy to survive, but, at reentry, the capsule (without its thermal protection!) will quickly BURN in the atmosphere, like happened with the (thermal shield damaged) Space Shuttle Columbia.
I'm aware that (both) the explosive bolts and the software that controls them will be designed to be very reliable (like the Challenger's SRB ring and the Columbia's ET foam...) but (in my opinion) if the capsule's thermal shield is FIRMLY JOINED with the main body, the Orion will be (very much) SAFER since a contingency like this (simply) NEVER CAN HAPPEN also after several Orion's flights!
There are (at least) three possible solutions to have (both) a soft landing and a TPS firmly joined to the Orion:
The first option is to restore the, old but reliable, Apollo's sea landing for the Orion that (thanks to more advanced flights software) may/will land in the Atlantic ocean near the KSC instead of the Apollo's complex Pacific ocean landing.
That option has (at least) two (possible) problems: a) the (near KSC) Orion's sea retrieval may cost less than Apollo but still too much, and... b) without the airbags an emergency landing on soil will be very hard and dangerous for the astronauts.
The second option is to use a set of, Soyuz-like, retro-rockets that burns in the last second before landing on soil.
That option was very reliable in 100+ Soyuz/Shenzhou landing but has (at least) two (possible) problems: a) if the retro-rockets don't work the landing on soil will be very hard and dangerous for the astronauts, and... b) one or more retro-rockets' protection-covers may detach before/while reentry and the high temperature plasma will enter inside the engines' outlets causing a Columbia-like damage/accident.
The third and BEST solution (in my opinion) is to build an Orion with a TPS firmly joined to the capsule and the main+backup parachutes and airbags outlets located in the Orion's sidewalls.
Thanks to its FIRMLY JOINED thermal shield, that solution (show in the image with my TBS-Orion) is the SAFEST possible for (both) sea and soil landings, also, with the parachutes' outlets located around the Orion's hatch (and the airbags' outlets in the opposite side) it offers an airplane-like landing with the astronauts' seats placed in a vertical position!
February 27 - 2007
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Copyright © 2007 Gaetano Marano - All rights reserved - base images used for the drawings are © NASA