Commercial spaceflight & then what?

"Hop David" wrote in message
...


Joe Strout wrote:
In article ,
Hop David wrote:


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


Of course you are. You just don't have the fuel to go any farther. If
my car runs out of gas halfway to San Jose, is it not halfway to San
Jose?


Well, that's true enough.

So when we get to LEO all we need to do is stand by the road and stick
out our thumb.

Basically yes.

Imagine the shuttle bringing up a TLI for a lunar mission.

Let's give it 60,000 lbs mass (you can pick the fuels, payload, etc.) at
(we'll be generous) $300,000,000.

So you're paying $5000/lb

Now, let's say something like Roton had succeeded.

I don't recall mass to orbit, but some of the schemes out there are already
talking $1000/lb or less.

Let's give it a payload of 2,000lbs, but a cost of $1000/lb.

You have to fly 30x missions, but it's still cheaper.

So, each of those 30 missions, you fill up your orbital depot and sell to
the highest bidder.


Sorta like the fact that when I drive to Jan Jose, someone else has
prepositioned the gasoline for me.



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

"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..."
Swap the first . and @ and throw out the ".trash" to email me.
Here's my email address for autospammers:

"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 , "Greg D. Moore
\(Strider\)" wrote:

"Hop David" wrote in message
...


Joe Strout wrote:
In article ,
Hop David wrote:


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


Of course you are. You just don't have the fuel to go any farther. If
my car runs out of gas halfway to San Jose, is it not halfway to San
Jose?


Well, that's true enough.

So when we get to LEO all we need to do is stand by the road and stick
out our thumb.

Basically yes.

Imagine the shuttle bringing up a TLI for a lunar mission.

Let's give it 60,000 lbs mass (you can pick the fuels, payload, etc.) at
(we'll be generous) $300,000,000.

Someone else is quoting $640 million per launch.

http://www.theatlantic.com/issues/20...asterbrook.htm

So you're paying $5000/lb

Now, let's say something like Roton had succeeded.

I don't recall mass to orbit, but some of the schemes out there are already
talking $1000/lb or less.

Let's give it a payload of 2,000lbs, but a cost of $1000/lb.

You have to fly 30x missions, but it's still cheaper.

$1000 x 2000lbs == $2,000,000 per launch. That sounds too good to be true!

So, each of those 30 missions, you fill up your orbital depot and sell to
the highest bidder.

Wouldn't you have to build the orbital depot first?

If nothing else, you'd need somewhere to house those assembling the lunar
mission's ship. As a benchmark, the ISS will be over 350 metric tons when
finished. Even if your depot was only one-tenth it's size, that would
still be a lot of missions to fly (at 2000 lbs apiece) before you could
even begin flying the missions to take the pieces of the lunar ship into
orbit. Not to mention the missions for rotating crews while the lunar ship
is being constructed.

--
Stephen Souter

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

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/

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

On Sun, 10 Aug 2003 19:02:53 +1000, in a place far, far away,
(Stephen Souter) made the phosphor on my
monitor glow in such a way as to indicate that:


$1000 x 2000lbs == $2,000,000 per launch. That sounds too good to be true!

Not to me, as long as you do enough launches.

So, each of those 30 missions, you fill up your orbital depot and sell to
the highest bidder.

Wouldn't you have to build the orbital depot first?

If nothing else, you'd need somewhere to house those assembling the lunar
mission's ship. As a benchmark, the ISS will be over 350 metric tons when
finished.

ISS is a lousy benchmark for an orbital propellant depot.

--
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..."
Swap the first . and @ and throw out the ".trash" to email me.
Here's my email address for autospammers:

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