Commercial spaceflight & then what?

Hop David wrote:

If you achieve LEO with an empty fuel tank you're not halfway there.

That depends on the payload.

Once you reach orbit cheaply you have a lot more options.

For example ion drives are not very expensive to launch, because they
use very little fuel.

Of course using ion drives for people is problematic due to the Van
Allen belts and because they can be rather slow, but there's many
tricks; for example you can use the ion drives to ferry around chemical
fuel. That way, the chemical rocket only needs to carry enough fuel to
reach the next fuel dump. Doing that linearises the rocket equation; it
saves lots and lots of fuel on high delta-v missions like going to Mars
or landing on the moon.

Hop
http://clowder.net/hop/index.html

Ian Woollard wrote:
Hop David wrote:

If you achieve LEO with an empty fuel tank you're not halfway there.


That depends on the payload.

Once you reach orbit cheaply you have a lot more options.

For example ion drives are not very expensive to launch, because they
use very little fuel.

Yes, I guess inexpensive LEO access could open the door for launching
many probes along the line of SMART-1.

And if Moore's law keeps on chugging along, the ion driven probes could
grow smaller and more powerful (frx denser ccd arrays).

And their information would be useful for colonization efforts.


Of course using ion drives for people is problematic due to the Van
Allen belts

I hadn't thought of that. I guess ion drives would have a strong
magnetic field.

and because they can be rather slow, but there's many
tricks; for example you can use the ion drives to ferry around chemical
fuel. That way, the chemical rocket only needs to carry enough fuel to
reach the next fuel dump. Doing that linearises the rocket equation; it
saves lots and lots of fuel on high delta-v missions like going to Mars
or landing on the moon.



Regards,
Hop
http://clowder.net/hop/index.html

Hop David wrote:

Of course using ion drives for people is problematic due to the Van
Allen belts


I hadn't thought of that. I guess ion drives would have a strong
magnetic field.

Not usually (the ions are accelerated electrostatically). He meant
the Van Allen belts around the Earth. Ion drive spacecraft spiral out
through the belts, getting a substantial radiation dose.

Paul

Hop David wrote:

Suppose a space tourism market does come to pass: Rich folk ride the
descendants of an X-prize winner to enjoy the view and weightlessness.
The flights would be suborbital or low earth orbit, no?

Would this make Mars, the moon, or even high earth orbit more accessible?

Hop
http://clowder.net/hop/index.html

It would show that if there's a tourist demand for suborbital/low
Earth orbit flights, there is quite probably such a demand for
destinations farther out, if the price is right.

And if you've gotten as far as regualar LEO tourism, including modest
'space hotels,' you've got a lot of the technology to go farther, in
hand, already...

"Hop David" wrote in message
...
Suppose a space tourism market does come to pass: Rich folk ride the
descendants of an X-prize winner to enjoy the view and weightlessness.
The flights would be suborbital or low earth orbit, no?

Would this make Mars, the moon, or even high earth orbit more accessible?

Hop
http://clowder.net/hop/index.html


No. None of the X prize ships are for LEO. They are all striving for a
roughly 60 mi altitude ballistic lob. It is HUGE leap in both technology
and cost to go from that to LEO capable vehicles. This competition may
spin off some minor new ideas and stimulate some interest in space
activities, but it does nothing to "make Mars, the moon, or even high earth
orbit more accessible."

On Thu, 7 Aug 2003 22:34:09 -0400, in a place far, far away, "Phil A.
Buster" made the phosphor on my monitor glow in such a way
as to indicate that:

"Hop David" wrote in message
...
Suppose a space tourism market does come to pass: Rich folk ride the
descendants of an X-prize winner to enjoy the view and weightlessness.
The flights would be suborbital or low earth orbit, no?

Would this make Mars, the moon, or even high earth orbit more accessible?

Hop
http://clowder.net/hop/index.html


No. None of the X prize ships are for LEO. They are all striving for a
roughly 60 mi altitude ballistic lob. It is HUGE leap in both technology
and cost to go from that to LEO capable vehicles. This competition may
spin off some minor new ideas and stimulate some interest in space
activities, but it does nothing to "make Mars, the moon, or even high earth
orbit more accessible."

Utter nonsense, spoken by someone completely ignorant of the problem.

--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org

"Extraordinary launch vehicles require extraordinary markets..."
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"Hop David" wrote in message
...
Suppose a space tourism market does come to pass: Rich folk ride the
descendants of an X-prize winner to enjoy the view and weightlessness.
The flights would be suborbital or low earth orbit, no?

Would this make Mars, the moon, or even high earth orbit more accessible?

Hop
http://clowder.net/hop/index.html

My plan is to skip low Earth orbit altogether and go straight to the moon.
Setting up a tourist business on the moon is more difficult than setting up
a tourist business in low Earth orbit, but on the moon, you can work on
multiple goals simultaneously. The missing link in space is mining and
manufacturing. Just making bricks in space would be an improvement over
what we have now.

Once you learn how to build buildings on the moon using local resources,
then you can build fairly nice hotels there. Tourists will have to spend
more, but they'll get a nicer place to visit. If there was a huge demand
for low Earth orbit, then a tourist business there would be useful, but I'm
dubious about the demand being there.

Once we have construction machines working on the moon, we can ship similar
machines to Mars and start building houses there.

In article , "Mike Rhino"
wrote:

"Hop David" wrote in message
...
Suppose a space tourism market does come to pass: Rich folk ride the
descendants of an X-prize winner to enjoy the view and weightlessness.
The flights would be suborbital or low earth orbit, no?

Would this make Mars, the moon, or even high earth orbit more accessible?

Hop
http://clowder.net/hop/index.html

My plan is to skip low Earth orbit altogether and go straight to the moon.

Do you mean your astronauts (and tourists) would be launched directly from
Earth to the Moon?

That would require very large launch vehicles, even if you did it the way
Apollo did. Surely a very expensive way of running your business!

--
Stephen Souter

http://www.edfac.usyd.edu.au/staff/souters/