Let’s assume that the human weighs 80kg. That gives 363kg to play with.
Assume no retrorockets so the thing just uses orbital decay to get down (and in fact cause of this we probably have another 30kg to play with). Could you design a super minimal craft capable of that? I see the following as necessary:
(a) some, probably aerodynamic, means of stabalising the craft’s orientation during reentry - optional but would help with:
(b) a heat shield just sufficient for this one re entry
(d)… the thing can be split apart in mid air so the human can jump out…
(e)… which implies a parachute as well
Obviously this is not a sensible or safe means of space travel but is it do able at all? How much oxygen is the person going to need and does the CO2 need venting?
The Mercury capsule had an orbital weight of 1,355, which is significantly more than a pegasus can launch. But if you don’t care about safety, maybe you can reduce that a bit.
MOOSE only weighed 90kg. That included an inflatable heatshield, reentry rockets, and a parachute, but not the weight of the astronaut or spacesuit. You could probably launch MOOSE, and a person in a spacesuit, with pegasus, assuming you can find someone daring enough.
Well, you could squeeze an astronaut in a spacesuit into the nose, and he could re-enter using something like the MOOSE system. But yeah you’d probably need some additional life support (I don’t think the suit alone would be able to operate long enough for the whole mission).
According tothis page the first stage accelerates the Pegasus from the cruising speed of the B-52 to 5000 MPH in 76 seconds. That’s an average og only about three Gs (Did I calculate that right?). If so that’s not to bad.
Damn it, I spent too long googling references and fixing spelling. AndrewL beat me to it.
Joking aside, LEO stands for “low earth orbit”, basically juuust enough above the atmosphere so that drag doesn’t (immediately) stop you from orbiting.
I’m just thrilled to learn about the balls-out-crazy MOOSE reentry system. Want to get out of orbit in an emergency? Climb in this garbage bag and fill it with expanding foam! What more could you want? Ok, we’ll add a quarter inch thick layer of rubber for a “heat shield”, and I guess you should have a parachute. If you really must insist on steering, you can carry your own hand-held rocket.
How far have light-weight materials come since the Mercury program? I’m just mildly curious how heavy a Mercury capsule would be with modern lightweight materials (of course, it’s entirely possible that modern lightweight materials were originally developed for things like the Mercury program and the answer would be “A bit less because radios are lighter now.”)
No reason to make the capsule a life-sustaining environment, when the suit can do the job. You’d just need an extra bottle of oxygen (and/or CO2 scrubber), maybe a battery, and a more absorbent diaper, all in place at launch time, to support a mission longer than an ordinary space suit can deal with… The capsule only needs to provide aerodynamic shape during launch, and a suitable shape + thermal protection + parachute during reentry. Something close to MOOSE ought to do the job.
We can assume that the astronaut’s suit includes a PLSS. That’s good for about 8 hours of oxygen supply, carbon dioxide removal, and temperature control. An EVA suitwith PLSS included weighs about 50kg.
