What it was like to fly the baddest airplane

> [after hearing he has to take the top off of the Mars Ascent Vehicle] I know what they're doing. I know exactly what they're doing. They just keep repeating "go faster than any man in the history of space travel", like that's a good thing. Like it'll distract me from how insane their plan is. Yeah, I get to go faster than any man in the history of space travel, because you're launching me in a convertible. Actually it's worse than that, because I won't even be able to control the thing. And by the way, physicists, when describing things like acceleration do not use the word "fast". So they're only doing that in the hopes that I won't raise any objections to this lunacy, because I like the way "fastest man in the history of space travel" sounds. I do like the way it sounds... I mean, I like it a lot.

But aren't the Soyuz capsules that dock with the ISS piloted and powered ?

You mean twice as fast as the ISS, don't you?

11 km/s is escape velocity at ground level: no way ISS could stay in orbit going twice that fast!

Hahah, when compared to Mach 22, is that pedantry relevant?

Fair record category would be “takes off under own power, sets record, lands by itself with all the equipment”. X-15 definitely doesn’t qualify.

[0] https://en.wikipedia.org/wiki/Mach_number

But again, I wrote rather short comment, and part of it was:

> There are humans there, they got up to speed and regularly come back

To put it in other words, to get to ISS, crew has to accelerate to it's speed, and to get back, to lose it.

I think you mean centrifugal force. Unfortunately, no, you don't feel quite that much less weight, because centrifugal force goes like the square of the velocity, so the ratio is the square of 6.2/22, or about 0.08, i.e., only 8%.

On any of the ballistic / into space flights, you would experience weightlessness between the engine cutoff and the point where atmospheric forces became noticable -- this is what the space tourism companies are aiming for.

I do not know if any flights were conducted at a constant altitude, but note that the centrifugal force goes by the square of the angular velocity.

Also, Mach numbers depend on atmospheric temperature and therefore indirectly on altitude. Strictly speaking, a Mach number for the ISS is meaningless, and even if we are being lax, the figure of Mach 22 is not directly comparable to the X-15 record Mach number. The comparison must be made between speeds, which are, approximately, 17,000 mph for the ISS and 4,500 mph for the X-15 record.

If we disregard the relatively small difference in the radius (from the center of the earth), then my BOE calculation suggests that the reduction in weight is about 7%.

Note, however, that while the motor is running, its acceleration is the biggest contribution to weight (reaching up to 4g as the fuel weight goes down.) Once it is cut off, then our assumption of level (i.e. non-ballistic) flight assumes that the airplane is capable of generating lift equal to its weight, which implies sufficient atmospheric density for the small wings to generate that lift. This, in turn, seems to imply enough density to produce a non-trivial deceleration due to drag, which also contributes to weight. Therefore, I doubt that there is any phase of the flight where the centrifugal reduction of weight is the dominant effect.

[1] https://en.wikipedia.org/wiki/Fictitious_force