Quote from: cscott on 07/24/2014 09:08 pmOn the video this is titled "landing burn". I don't believe the wording in the video, at least not precisely. Obviously an engine is burning. But there is a big difference in the flame size at +11:12 vs +11:33 , and the earlier one has a pulsating pattern. Also, time to decelerate from terminal velocity to hover is T = V * a where a = m / (F-W) = 1/(F/m - g) => T = V/(F/m - g) . Guesses of V=100m/s, F = 600 kN, m = 18000 kg yields deceleration of 30g and firing time of 3 seconds, which is consistent with my parsing of the video. However, the video label "landing burn" occurs 24 seconds before splashdown.
On the video this is titled "landing burn".
I don't think you need a quadcopter when you have Elon's personal jet in the area.
We don't know what other free variables were specified on this landing attempt....These landing attempts are about supersonic retropropulsion and reentry heating on the structure, which is the flight regime F9R can't easily test. (Propellant quantities can be computed, they don't need a test flight for that.)
Crazy talk. The progression between cassiope, CRS-3 and ORBCOMM flight has been landing closer to shore each time.
That would defeat the point. FH is a three-stage rocket. The two boosters are the first stage. Getting rid of a stage has a large negative impact on performance; study the rocket equation.
...Economics is pretty pliable. It hasn't been too long ago since the days when discussions of cheap re-usability itself was heresy; yet here SpaceX are... making attempting to make the economics work.
Quote from: cscott on 07/24/2014 09:08 pmOn the video this is titled "landing burn". I don't believe the wording in the video, at least not precisely. Obviously an engine is burning. But there is a big difference in the flame size at +11:12 vs +11:33 , and the earlier one has a pulsating pattern.
It hasn't been too long ago since the days when discussions of cheap re-usability itself was heresy; yet here SpaceX are... making the economics work.
At this point, we are highly confident of being able to land successfully [..] and refly the rocket with no required refurbishment.
Quote from: SpaceXAt this point, we are highly confident of being able to land successfully [..] and refly the rocket with no required refurbishment.I don't know how they can make any claims about refurbishment if they haven't recovered a stage yet.
What's that got to do with anything? It's the reentry that does the damage (if any).
Quote from: QuantumG on 07/26/2014 03:28 amWhat's that got to do with anything? It's the reentry that does the damage (if any).On the contrary, launch and landing are probably harder on the vehicle than a few Mach reentry. Or at least, SpaceX likely believe so.
Quote from: Robotbeat on 07/26/2014 03:30 amQuote from: QuantumG on 07/26/2014 03:28 amWhat's that got to do with anything? It's the reentry that does the damage (if any).On the contrary, launch and landing are probably harder on the vehicle than a few Mach reentry. Or at least, SpaceX likely believe so.I'm not arguing that. The point is they can't possibly know that yet. Until they recover a stage, they won't know how beaten up it is.
Quote from: QuantumG on 07/26/2014 12:16 amQuote from: SpaceXAt this point, we are highly confident of being able to land successfully [..] and refly the rocket with no required refurbishment.I don't know how they can make any claims about refurbishment if they haven't recovered a stage yet.They are claiming they are confident, not that they know it for a fact. They don't have the stage but they have the telemetry and whatever simulations they've run. They have a fair idea the stresses stage encountered on reentry and they know everything was functioning as they expected.When they recover one, especially if they land one, then they'll know for a fact. Maybe it will turn out they are wrong, but I can't see the problem with being them saying they are confident at this point.
When's the last time SpaceX wasn't highly confident about something? That's sort of their defining trait isn't it?