Spaceship One stepping-stone or dead-end?

MichaelJP wrote:
Was wondering after watching the webcast yesterday, obviously relatively
cheap sub-orbital flights are now a reality once they get the bugs ironed
out...

But does the development of Spaceship One help with the much more useful
goal of cheaper access to orbit? As a non-expert, I understand that a
spacecraft capable of low earth orbit requires a velocity of at least
18,000mph compared to SS1's 2000mph, which is obviously a massive
difference.

So would an orbital design have to be totally different and we'd end up back
with multi-stage expendable rockets?

- MP


Cheap access to space needs new technology. None of the commercial
flights for the X prize is showing any breakthrough in propulsion
methods. They are just adapting current technology for people with
100 000 dolars to spend in a flight of a few moments...

Jeff Findley wrote:
"jacob navia" wrote in message
...

Cheap access to space needs new technology.


Not at all.


None of the commercial
flights for the X prize is showing any breakthrough in propulsion
methods. They are just adapting current technology for people with
100 000 dolars to spend in a flight of a few moments...


What leads you to believe that we need a "breakthrough in propulsion
methods" to achieve private manned spaceflight?

The difference in speed needed to get in orbital flight. Sub-orbital
flight is now possible, and it was in 1963, when the X15 record was
established that SS1 has just broken by a few km/hour.

SS1 is now at the stage of X15 development.

Earth orbit however needs substantially (a factor of 9) more speed
and this means at least a factor of 9 of costs to get it.

You mention the russian technology, but consider that each flight
is much more than a couple of million dollars (at least!)

This means that until humans develop an unexpensive way of getting
into space, rockets of several stages will be the only solutions.
And they *are* expensive.

jacob

Was wondering after watching the webcast yesterday, obviously relatively
cheap sub-orbital flights are now a reality once they get the bugs ironed
out...

But does the development of Spaceship One help with the much more useful
goal of cheaper access to orbit? As a non-expert, I understand that a
spacecraft capable of low earth orbit requires a velocity of at least
18,000mph compared to SS1's 2000mph, which is obviously a massive
difference.

So would an orbital design have to be totally different and we'd end up back
with multi-stage expendable rockets?

- MP

On Thu, 30 Sep 2004 12:18:26 +0100, in a place far, far away,
"MichaelJP" made the phosphor on my monitor glow
in such a way as to indicate that:

Was wondering after watching the webcast yesterday, obviously relatively
cheap sub-orbital flights are now a reality once they get the bugs ironed
out...

But does the development of Spaceship One help with the much more useful
goal of cheaper access to orbit?

Not directly, in terms of technology. What it helps with is changing
mindsets, and raising funds for other designs that do.

So would an orbital design have to be totally different

Yes.

and we'd end up back
with multi-stage expendable rockets?

No. There are other options.

"Rand Simberg" wrote in message
...
On Thu, 30 Sep 2004 12:18:26 +0100, in a place far, far away,
"MichaelJP" made the phosphor on my monitor glow
in such a way as to indicate that:

Was wondering after watching the webcast yesterday, obviously relatively
cheap sub-orbital flights are now a reality once they get the bugs ironed
out...

But does the development of Spaceship One help with the much more useful
goal of cheaper access to orbit?

Not directly, in terms of technology. What it helps with is changing
mindsets, and raising funds for other designs that do.

So would an orbital design have to be totally different

Yes.

and we'd end up back
with multi-stage expendable rockets?

No. There are other options.

Would appreciate any links, references?

Thanks,
- MP

On Thu, 30 Sep 2004 13:35:04 +0100, in a place far, far away,
"MichaelJP" made the phosphor on my monitor glow
in such a way as to indicate that:

and we'd end up back
with multi-stage expendable rockets?

No. There are other options.

Would appreciate any links, references?

I have nothing specific in mind, but there are many ways to get to
orbit besides expendables. I don't know which will prove the best,
but the market will figure it out.

MichaelJP wrote:
Was wondering after watching the webcast yesterday, obviously relatively
cheap sub-orbital flights are now a reality once they get the bugs ironed
out...

But does the development of Spaceship One help with the much more useful
goal of cheaper access to orbit? As a non-expert, I understand that a
spacecraft capable of low earth orbit requires a velocity of at least
18,000mph compared to SS1's 2000mph, which is obviously a massive
difference.

So would an orbital design have to be totally different and we'd end up back
with multi-stage expendable rockets?
I don't think we will ever go into orbit with something that is very
similar to SS1. But I also don't think we will do it with multi-staged
expendable rockets.
If there is a market for the flights the SS1-class offers, I'm sure they
will continue development to push the envelope of current designs
further and try out new designs to add every now and then some zero-g
time to the flights, as this and the sight is what the people want.
At one point, they may develop some suborbital transportation system
which does intercontinental jumps, thus also open the market for this
kind of transport (New York - Sydney in one hour or something like
this). And then, one day, it will only be a final small step to get into
orbit from this point.

So, SS1 *is* a stepping stone. But the next stepping stones will look
more and more different.

"MichaelJP" wrote in message
. ..
Was wondering after watching the webcast yesterday, obviously relatively
cheap sub-orbital flights are now a reality once they get the bugs ironed
out...

But does the development of Spaceship One help with the much more useful
goal of cheaper access to orbit? As a non-expert, I understand that a
spacecraft capable of low earth orbit requires a velocity of at least
18,000mph compared to SS1's 2000mph, which is obviously a massive
difference.

So would an orbital design have to be totally different and we'd end up
back
with multi-stage expendable rockets?

While the design may need to be completely different, SS1 did what it was
supposed to do. It showed that you can build and fly an actual spaceship
for far less than NASA cost models would predict. Far, far less money was
spent on SS1 than was spent on Mercury Redstone, and Mercury Redstone didn't
enter orbit either.

The point is that when private industry (I'm ignoring the big aerospace
contractors that work for NASA) finally get around to building an orbital
craft, it will be built for far less money than "traditional" spacecraft.

Jeff
--
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"jacob navia" wrote in message
...
Cheap access to space needs new technology.

Not at all.

None of the commercial
flights for the X prize is showing any breakthrough in propulsion
methods. They are just adapting current technology for people with
100 000 dolars to spend in a flight of a few moments...

What leads you to believe that we need a "breakthrough in propulsion
methods" to achieve private manned spaceflight? There isn't any reason that
a well designed TSTO (or perhaps a three stage to orbit) using conventional
propellants can't reach orbit. LOX and kerosene would work just fine.

Technology from the 1950's and early 1960's is sufficient for putting people
in orbit. If the Russians could do it with Vostok in 1961, why do we *need*
any breakthroughs in technology? Please note that Vostok was launched with
essentially the same LOX/kerosene powered first and second stages that are
still used today to launch Soyuz and Progress. For some reason, the
Russians seem to think that 40+ year old technology works just fine for
getting to LEO.

Jeff
--
Remove icky phrase from email address to get a valid address.

"jacob navia" wrote in message
...
Jeff Findley wrote:
"jacob navia" wrote in message
...

Cheap access to space needs new technology.


Not at all.


None of the commercial
flights for the X prize is showing any breakthrough in propulsion
methods. They are just adapting current technology for people with
100 000 dolars to spend in a flight of a few moments...


What leads you to believe that we need a "breakthrough in propulsion
methods" to achieve private manned spaceflight?

The difference in speed needed to get in orbital flight. Sub-orbital
flight is now possible, and it was in 1963, when the X15 record was
established that SS1 has just broken by a few km/hour.

Then explain to me how the Soyuz launch vehicle was able to put Vostok in
orbit using conventional LOX/kerosene engines.

SS1 is now at the stage of X15 development.

More or less (if you ignore the high speed X-15 flights).

Earth orbit however needs substantially (a factor of 9) more speed
and this means at least a factor of 9 of costs to get it.

I know, I have an Aerospace Engineering degree.

You mention the russian technology, but consider that each flight
is much more than a couple of million dollars (at least!)

This is because they throw away the entire vehicle after each flight. Their
only serious attempts at reusability were to "copy" the US shuttle
(reusable) and their own Energia (who's boosters were planned to be
reusable). Otherwise, they keep making the same old Soyuz and Proton launch
vehicles because they don't have the money to develop anything new.

This means that until humans develop an unexpensive way of getting
into space, rockets of several stages will be the only solutions.
And they *are* expensive.

To date, all launch vehicles (except the US shuttle, which is really only
partially reusable) have been expendable. Making them reusable would be a
huge shift in design, but would require no new technology. Large,
lightweight, empty rocket stages should be easier to recover than the large,
heavy US space shuttle.

Jeff
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