Stuf4 wrote:
As brutally seen in 1986, the crew cabin is much more robust than
other parts of the orbiter. There is a reason for this. It is
designed as a pressure vessel, whereas other parts of the orbiter have
no such requirement.

It is *easy* to augment the design of this pressure vessel so that it
then becomes a crew escape module. It is also easy to determine c.g.
limits of this module so that after orbiter breakup it has a stable
flight. An escape module design that would have permitted safe escape
for both -51L and -107 crews need not have had excessive weight.

It's not *easy*, as you say. This has been studied as part of NASA's
new safety initiative started a few years back. As I recall, there were
three concepts being worked, one being a full crew escape module. The
study showed a substantial sacrifice to both payload bay volume and
payload weight as to make the shuttle no longer a feasible design as a
payload-to-orbit capability.

Another concept concerned separation of flight deck and mid deck. I
don't recall the third concept.

None were *easy* to implement.




A smart compromise would have been a *lightweight crew escape module*.
There is no need for a huge parachute system. No need for
impact/floatation bags. No need even for giant-thrust rocket
separation motors.

After pyrotechnics separate the module from the rest of the vehicle, a
small motor can be used to build separation (-51L showed that no motor
at all is needed). Then instead of a giant parachute designed to give
the escape module a soft landing, all that is needed is a
stabilization chute system that slows the module down enough for the
crew to bail out of (no escape pole needed because the wings are long
gone).


In order to clear the large vertical stabilizer or wing leading edge in
the worst case scenario, while keeping the g-load within survivable
limits, there can be no *small motor*. Several rockets would be needed
to maneuver the escape module clear. I think parachutes and parafoils
were both considered.

This is just one idea. I'm sure that others were proposed.


Yes.

[snip]

In summary, it would have been easy to design the shuttle with crew
escape capability covering the vast majority of ascent/entry. It
wasn't done. After the fact it becomes very hard to retrofit this
capability. This point has been discussed many times. Here's one
post (from just prior to Feb1st) with more info:


This may be true, if you're considering designing the shuttle from
ground up with crew escape module. I can't believe that this was not
considered, but I don't know why it was not employed. Perhaps there's
someone else in this ng who knows the particulars.