jkl@csli.STANFORD.EDU (John Kallen) (01/13/89)
I've been wondering about what would happen if, when launched, one of the SRB's on the shuttle fires, say, a second before the other one does. What prevents the whole orbiter assembly from somersaulting? Also, does anybody know if the SRB's *do* fire asynchronously? What are the safety precautions used to prevent the assmebly from spinning out of control due to thrust mismatches? I find the questions interesting since I read somewhere that once ignited, a SRB is *very* hard to 'stop'... TNX4info, John. _______________________________________________________________________________ | | | | |\ | | /|\ | John Kallen "The light works. The gravity | |\ \|/ \| * |/ | |/| | | PoBox 11215 works. Anything else we must | |\ /|\ |\ * |\ | | | | Stanford CA 94309 take our chances with." _|_|___|___|____|_\|___|__|__|_jkl@csli.stanford.edu___________________________
henry@utzoo.uucp (Henry Spencer) (01/15/89)
In article <7089@csli.STANFORD.EDU> jkl@csli.UUCP (John Kallen) writes: >I've been wondering about what would happen if, when launched, one of >the SRB's on the shuttle fires, say, a second before the other one >does. What prevents the whole orbiter assembly from somersaulting? Nothing. This is known as an "unsurvivable accident". >Also, does anybody know if the SRB's *do* fire asynchronously? What >are the safety precautions used to prevent the assmebly from spinning >out of control due to thrust mismatches? The two SRBs are matched fairly carefully, including using motor segments from the same production batch. Minor imbalances can be handled using the normal steering systems, and indeed are to be expected. Considerable pains are taken to make ignition very reliable and to make it happen exactly simultaneously. -- "God willing, we will return." | Henry Spencer at U of Toronto Zoology -Eugene Cernan, the Moon, 1972 | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
karn@ka9q.bellcore.com (Phil Karn) (01/16/89)
>I've been wondering about what would happen if, when launched, one of >the SRB's on the shuttle fires, say, a second before the other one >does. The chances of this are *extremely* remote. It is more likely that one SRB simply wouldn't ignite at all, but the chances of this are also pretty small considering the redundancy and overdesign in the SRB ignition system. Small assymetries in thrust between the SRBs can and do occur, mainly due to temperature variations. The orbiter can handle these. Phil