# 16295 byJim Lemmon on Jan. 22, 2002, 5:44 p.m.
Member since 2022-08-22
Most of the mass drivers that I have read about use a
circular track for acceleration. So, instead of a hole
at the bottom of the mountain there could be a
circular track for acceleration that would release
into the track arching upward. It would have to be a
gentle arc to not waste energy in turning fast.
near escape velocity around sea level would be the
atmosphere. The atmosphere is just too dense to go
that fast It would build up too much heat and too much
resistance.
NASA has the intent to research magnetic catapults the
same as our mass driver, the problem is they don't
have any money to do it. They are giving a few dollars
for the basic research to someone can't remember who.
The scramjet is a fact. The problem will be in
marrying it to a rocket and getting it to supersonic
speed so it can function.
# 16296 byrmenich@... on Jan. 22, 2002, 5:58 p.m.
Member since 2022-08-22
Mass drivers are linear. Slingatrons are circular (well, actually
spiral, not circular).
Jim Lemmon lemmonjim@...
01/22/02 06:44 PM
Most of the mass drivers that I have read about use a
circular track for acceleration. So, instead of a hole
at the bottom of the mountain there could be a
circular track for acceleration that would release
into the track arching upward. It would have to be a
gentle arc to not waste energy in turning fast.
I think the main problem with this idea of gaining
near escape velocity around sea level would be the
atmosphere. The atmosphere is just too dense to go
that fast It would build up too much heat and too much
resistance.
NASA has the intent to research magnetic catapults the
same as our mass driver, the problem is they don't
have any money to do it. They are giving a few dollars
for the basic research to someone can't remember who.
The scramjet is a fact. The problem will be in
marrying it to a rocket and getting it to supersonic
speed so it can function.
# 16297 bycfrjlr@... on Jan. 22, 2002, 7:05 p.m.
Member since 2022-08-22
> Most of the mass drivers that I have read about use a
> circular track for acceleration. So, instead of a hole
The only place I saw anything like that was in the 1950's scfi move "When Worlds Colide" :-)
Most of the "real" mass drivers I have read about, and the SSI video which I have seen, are straight bore.
> at the bottom of the mountain there could be a
> circular track for acceleration that would release
> into the track arching upward. It would have to be a
> gentle arc to not waste energy in turning fast.
>
Why is this better than a straight driver ?
Changing direction is very inefficient because it wastes energy. It is only efficient to deliver the acceleration into a single fixed velocity vector.
> I think the main problem with this idea of gaining
> near escape velocity around sea level would be the
> atmosphere. The atmosphere is just too dense to go
> that fast It would build up too much heat and too much
> resistance.
>
Some energy will be lost to air resistance.
But the projectile will be moving so fast that it will be otu of the atmosphere within a few seconds, so the period of drag loss will be relatively short.
A heat shield will be required to protect the payload.
> NASA has the intent to research magnetic catapults the
> same as our mass driver, the problem is they don't
> have any money to do it. They are giving a few dollars
> for the basic research to someone can't remember who.
It would certainly be great to get some funding for more mass driver research.
Not sure if NASA is the best choice though.
> The scramjet is a fact. The problem will be in
> marrying it to a rocket and getting it to supersonic
> speed so it can function.
>
The Russians already did this experimentally nearly ten years ago.
They put a scramjet on an old ICBM, the period of SCRAM operation was quite short, only a couple of seconds IIRC.
Has anybody else done this since the one successful Russian flight ?