Shuttle Explosive Bolts & Grissom's Experience in Mercury

As we all remember, shortly after splashdown, the explosive bolts on
Grissom's Mercury spacecraft Liberty Bell 7 fired prematurely, blowing
the hatch cover off, and the capsule sank into the water. That accident
has never been fully explained.

Given that, what steps did NASA take to ensure that there could not be a
similar accidental premature catastrophic firing of the explosive bolts
that hold the SRBs and the External Tank to the Orbiter?

For example, I assume that if there were a malfunction and the SRBs and
External Tank didn't separate automatically, the Shuttle crew is able to
do the separation manually? If so, what would prevent the Shuttle crew
from accidentally causing the separation prematurely by human error?

[Apologies in advance if this has been discussed before I joined this NG]


--
Steven D. Litvintchouk
Email:

Remove the NOSPAM before replying to me.

"Steven D. Litvintchouk"
If so, what would prevent the Shuttle crew
from accidentally causing [SRB] separation prematurely by human error?

Answer to most of your question can be found on NASA's shuttle reference page.
Fairly detailed descriptions of shuttle systems for interested persons.

http://spaceflight.nasa.gov/shuttle/...ref/index.html

Kent Betts wrote:

"Steven D. Litvintchouk"
I assume that if there were a malfunction and the SRBs and

External Tank didn't separate automatically, the Shuttle crew is able to
do the separation manually


As I understand it, there is no manual sep provided for the SRBs because it is
not practical or useful to serparate the SRBs while they are producing thrust,
and when they finish, the computer blows the bolts. There is a backup timer
device that blows the SRBs in the event that this "= 50 psi" signal is not
received.

http://spaceflight.nasa.gov/shuttle/...ref/index.html

Thanx!


--
Steven D. Litvintchouk
Email:

Remove the NOSPAM before replying to me.