> fairing separation (shedding excess weight, but constrained by the aerodynamic advantages and protections of the fairing itself) tends to occur before major pitch-over.
Not for the launches I've watched, e.g. SpaceX pitches through 45 degrees at ~61km of altitude, whereas fairing separation doesn't happen until 82km altitude (by which time it's of course pitched down significantly further). Is that unusual?
> That's getting to be close to what's useful for space launch, but whilst the altitude is useful, the velocity remains low relative to orbital velocities.
True, but also potentially positive; if (big if) you can figure out the other issues, then the faster you go the higher you can continue to take in enough air to be useful.
FWIW, I tried to find an altitude-velocity diagram of a typical rocket launch without luck. Lots of diagrams, none with specific altitude & velocity components.
61 km altitude is FL200, a/k/a 200,000 feet altitude. That's above the operating altitude of any air-breathing so far as I'm aware.
As I'd noted earlier, the SR-71 (in regular operation) was limited to FL85, and the all-time altitude record was FL123, still 77,000 feet below your SpaceX Falcon pitch-over. The SR-71 saw significant thermal heating given its speed. The only aircraft that have gone higher are the rocket-powered X-15, with an all-time record of 347,400 ft (105,900m) in 1963, and Spaceship One, at 367,490 ft. (112,010 m), in 2004. Both the latter were themselves air-launched, though largely to gain initial altitude given the power and speed achieved under rocket power.
I'm unable to read the Twitter thread itself, so if there's any specific technical capability mentioned, I'm missing it. I'd be very surprised if the designs would exceed FL100, let alone FL200.
Not for the launches I've watched, e.g. SpaceX pitches through 45 degrees at ~61km of altitude, whereas fairing separation doesn't happen until 82km altitude (by which time it's of course pitched down significantly further). Is that unusual?
> That's getting to be close to what's useful for space launch, but whilst the altitude is useful, the velocity remains low relative to orbital velocities.
True, but also potentially positive; if (big if) you can figure out the other issues, then the faster you go the higher you can continue to take in enough air to be useful.