Actually, since Ares I-X is only a 1st stage booster check (2nd stage and up are all dummies,) and since the booster being tested is a 4 segment solid rocket motor with a dymmy fifth segment, it won't even really be a test of an operational five segment RSRM: Isp should be in the neighborhood of 265-268 seconds.

When the J-2X becomes operational and is used in the upperstage, the Isp should be just about 425-450 seconds.

I guess this this is mainly a test for the stability issue that have been raised?  As you know I'm very critical of this whole Apollo Redux approach to space that has been chosen by NASA.  But, since it is the only space program well have I'm for it!  Best of luck to the Aries 1-X team!

NASA is claiming a big sucess.  As for the dummy second stage it would most likey be different if it was under power and had the full inertia of a real second stage and the Orion CSM.  At least I hope so.

The USS, or upper-stage simulator, was a spot on mass duplicate of the fully fueled upper stage. The stage was balasted 'precisely' to create a nearly identical mass-moment of inertia replica of the real thing. So, had that been a live stage, I doubt that it could have functioned. This would have been a LOS (Loss of Stage) and possibly even a LOC (Loss of Crew) event.

I was watching the video replays they have on NasaSpaceFlight.com, and it sure looks like the USS may have 'recontacted' the 1st stage--a euphamism for collision which is never supposed to happen.

I wouldn't worry about it except that it happened so damn fast--I doubt ullage rockets could have controlled the yaw-pitch moments that must have been exhibited by this vehicle at the moment of seperation. Something is way off on this...I'm glad it was only a test flight. I guesss we'll just have to wait for Ares 1-Y to see if they fix it.

Ty

This is interesting--a double parachute failure (out of 3) caused the SRB to impact the ocean hard enough to buckle the motor case:

http://www.space.com/missionlaunches/091030-ares-1x-parachute-update.html

Ouch!

I'd bet money that the this was probably caused by damage inflicted from a recontacting (collision) between the 1st stage and the USS during the flight.

Normally, stage seperations are not done with explosive bolts, per se. Usually the process is accomplished by using a very short section (usually 4-6 inches high) of thin  sheet which formed into a cylinder that is the same diameter of the vehicle. Using flanges on top and bottom, this 'seperation plane' is literally bolted onto the top of the interatage. Along the inside circumference of this 'seperation plane' is a coil of flexible shaped charge--a thin walled metal tube containing high explosives, usually PETN, with a wedge shaped cross-section. The shaped charge is wrapped around the inside circumference, and slightly overlapped--one pyrotechnic charge--a NASA Standard Initiator--is plugged into each end of the cord. Both are fired simultaneously, even though only one is needed to the do the job (for redundancy.) The detonation of the shaped charge very quickly and surgically cuts through the thin metal of the short cylinder---it takes milliseconds to accomplish severing this structural connection.

Such a seperation joint is far stronger and structurally superior to one using explosive bolts, and it requires only two NSTI (nasa standard initiators) for full redunancy, while each explosive bolt would require  two pyro initiators and you'd have to have a lot of them (maybe like 400 or so) to do the same job.



-- Edited by GoogleNaut on Monday 2nd of November 2009 05:13:30 PM