Re: How Rockets Differ From Jets


>Brad Guth wrote:
> I like the notion of using extremely large surface area ceramic
> air-breaks, as perhaps trailing edge fold-ups and fold-down flaps or
> whatever formula of providing V-expanding surfaces. Then how about
> plan-B of creating a disposable ceramic parachute, using that nifty CNT
> fiber as the chute tether lines?


Air brakes can effectively bring speed to 'low friction', say mach 20,
in about 1 minute. So, air brakes can defeat the worst of the reentry
heat, taking a seeminly insolvable thermodynamic problem down to size.

And, yes, trailing edge fold-ups/downs can be used. The Shuttle has
them and they work, but were not designed for maximum reentry braking
but, rather, for braking prior to landing. They tiled them, however,
allowing their use sooner than they were originally designed for. They
work.

They should have been used on the last flight of Columbia, but it was
not protocol, and no one thought of it. You just pump them a bit.
This gives your body a chance to recover from high G load, and it gives
the trailing edge flaps a chance to recover from the high thermal.

Disposable parachute is a bit extreme and does not take into account
the enormous G forces generated by slowing down . . . instantly. It
will take a shovel to remove the astronauts.


> How about using a disposable composite ball of basalt, of an extremely
> large enough sphere (artificial meteor) so that your Spaceplane could
> just safely follow it in (perhaps as somewhat in-tow by a CNT tether)
> as per getting safely through the upper atmosphere, then allowing the
> remains of that disposable and relatively cheap Spaceball to land
> directly on top of GW Bush and *** Cheney, as now you'd be killing off
> more than those usual two birds with one stone.


The Administration won't go for it. And, following a giant ball of
basalt would cause your spaceplane to slam into the back of it. Sorry,
no funding for this one.


> >Reverse thrust with subsequent hydrogen cooling of the hull and
> >interior is great as long as the returning spaceship has a supply of
> >fuel left.
> I believe this could in a big and powerful way easily replaced with
> those retro-radon-->ion thrusters as powered via the onboard Radium
> reactor/radon generator (or He3 fusion if possible). The same
> sub-frozen radon liquid could also be discharged for accomplishing the
> necessary external surface cooling, or just evaporated within the hot
> skin of the Spaceplane and then as a nicely warmed gas be fully
> utilized as ion fuel, thus no wastage or other harmful discharges
> whatsoever.


The cooling from the hydrogen fuel is essential for both the hull and
interior. Unless, of course, you like a 1000 deg. F. cockpit with only
your nomex flight suit between you and . . . cremation. That is what I
meant when I said: hot, hot, hot.

If, however, you had no hydrogen fuel the ion thrusters could be
designed in such a way that they would reverse thrust. This would help
some, but 'air brakes' and a 20,000 deg. F. certified hull made of
nanotubes and Corelle is what would mainly save your skin.

Nanotubes are extremely thermally conductive and this prevents 'hot
spots' on the hull, like on the leading edges. Corelle has been tested
to 20,000 deg. F. Great stuff.

Once possibility is to have 'air brakes' with fold down/up trailing
edge flaps and have an 'emergency air brake' with the two big slabs of
Corelle sticking up into the airflow.

This would help a lot returning from Venus at 200,000 mph because of a
good slingshot, finding out you had a hydrogen leak, and enable you to
stop quick in the atmosphere so you don't have to listen to your face
bubble and fry like bacon in hot grease.


tomcat

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