Quote from: Garrett on 04/02/2013 12:59 pmQuote from: Chris-A on 03/31/2013 04:27 pmElon's twitter feed could be a good indication on how well the vacuum chamber testing goes. If a week or two goes by without anything, then it might be time to worry about the schedule.That might be true in a world without ITAR. But we're not living in such a world. Bragging about a successful test is not prohibited by ITAR.
Quote from: Chris-A on 03/31/2013 04:27 pmElon's twitter feed could be a good indication on how well the vacuum chamber testing goes. If a week or two goes by without anything, then it might be time to worry about the schedule.That might be true in a world without ITAR. But we're not living in such a world.
Elon's twitter feed could be a good indication on how well the vacuum chamber testing goes. If a week or two goes by without anything, then it might be time to worry about the schedule.
Quote from: pericynthion on 04/02/2013 05:21 pmQuote from: Garrett on 04/02/2013 12:59 pmQuote from: Chris-A on 03/31/2013 04:27 pmElon's twitter feed could be a good indication on how well the vacuum chamber testing goes. If a week or two goes by without anything, then it might be time to worry about the schedule.That might be true in a world without ITAR. But we're not living in such a world. Bragging about a successful test is not prohibited by ITAR.It is if you include measurements with unit's like inches
I guess there are three options:-1) start low, and ramp up the re-entry speed until they find a problem - either break-ups or in post-flight analysis.2) start high, and ramp down the re-entry speed until one survives. [Edit: least likely, I think.]3) target the expected re-entry speed and see how it copes, then adjust as required.
Does anyone know what the staging altitude and velocity will be? What they may be? Are we expecting it to flip end for end immediately on separation and do the retro-burn, or do we expect some other flight profile?
At what altitude is the entry interface?
Quote from: aero on 04/07/2013 09:12 pmAt what altitude is the entry interface?Was 400kft for Shuttle. Don't know if it's different for F9.
As has been mentioned before up-thread, it's not the vertical velocity component that's the problem, it's the horizontal moving like a bat-out-of-hell part that will cause most of the trouble. Straight vertical drop should reach reasonably slow terminal velocity all by itself, just like Felix Baumgartner when he jumped out of the Red Bull capsule - without a rocket burn to slow him down.
Quote from: MP99 on 03/30/2013 10:19 amI guess there are three options:-1) start low, and ramp up the re-entry speed until they find a problem - either break-ups or in post-flight analysis.2) start high, and ramp down the re-entry speed until one survives. [Edit: least likely, I think.]3) target the expected re-entry speed and see how it copes, then adjust as required.Binary search / bisection, which is similar to your #3, is much more efficient in terms of number of tests needed than #1 or #2.
Speaking of propellant settling, how does that work anyhow? Would they wait till they encounter some drag to settle the propellant to the bottom of the tanks?
Quote from: Kabloona on 04/07/2013 09:23 pmQuote from: aero on 04/07/2013 09:12 pmAt what altitude is the entry interface?Was 400kft for Shuttle. Don't know if it's different for F9.400kft is 122 km. I think it will be lower for the F9 because, when staging at mach 6, there is only enough kinetic energy to coast upward against gravity for an additional 30 to 35 km above the staging altitude. I don't know the staging altitude of the F9 but I think it is lower than 90 km. My atmospheric calculator table runs out at 86 km altitude, and the atmosphere is pretty thin that high up.
It wouldn't be that different if you shot it at an angle or straight up. In fact, the one straight up would have significantly higher reentry forces (and, I believe, heat load).
Well, well, well......SFN now lists this flight at July 9 at 9-11 am PDT (16:00-18:00 GMT). Surely not three F9's in July!? (or heck five F9-1.1 between July and November?)Edit: Thaicom 6 launch date now listed in August, so at most only 2 F9s in July. (but the second possibility still stands!)