Reentry prize?

Pete Lynn wrote:

"Ruediger Klaehn" wrote in message
...
Pete Lynn wrote:

I am not sure if reentry and landing can really be separated and
pursued in isolation, too many unnatural distortions.

My proposal is not separating reentry and landing. You have to
get a payload from orbital velocity and orbital altitude to zero
velocity and zero altitude without cooking or breaking it. That
includes both reentry and soft landing.

Actually I meant this in the greater context, I am not sure that you
would want to separate such reentry testing from that of the launch
vehicle. The design of one effects the other to perhaps too great an
extent. The excessive tendency to try to compartmentalize out of
complexity generally results in good detailed design but bad overall
design, which is currently the more critical. This is something the
space industry is particularly noted for and the reason often attributed
for the failure to achieve CATS.

Yes, a price for a complete space transport would certainly be the best
approach. But you would have to offer at least 100 Million $, probably more
like 1 Billion $, to get many participants.

A reentry and landing price with low cost launch vehicles could be done with
much less money.

[snip]
I like the idea. This would be a good thing for NASA or
DARPA to offer.

But I think the followon for the X-Prize has got to be a manned.
The X-Prize would never have generated that much excitement if
it were a much more ambitious unmanned mission.

Agreed, as stated above. Though I would say that of the many groups
going for the X-Prize only one seems on track to get it in the given
time. Ideally it could have been a competition in space between many
groups, unfortunately few have developed actual vehicles.

There is a lot of progress in many teams. Maybe there will be some
surprises. And the 2004 constraint was nessecary to obtain the money.

I fear the all or nothing prize structure does not encourage the ongoing
depth and diversity of industry required for a serious crack at CATS. I
think we need more groups developing more commercial hardware at lower
costs, we need a highly competitive ongoing industry for which every day
is a new race. The market needs to be more integral to the process such
that entry barriers to commercial sustainability are lowered.

We will have that if the X-Prize is successful. Once you get things going it
is much easier to obtain money. If the X-Prize is claimed this year, I bet
that there will be another prize offered. And all the people who have built
hardware for the X-Prize will be able to participate.

Len wrote:

[snip]

Have you been working on the newest design from Len Cormier? It looks
similar to something you have proposed a few years ago.

Yes indeed, the concept is in part inspired by inputs from
Pete and Robert Lynn--as implied by the credit to Peter Lynn
Kites on the title page of our presentation at SAS 2004.
There's still a lot of updating needed on our web site;
however, the SAS 2004 presentation: Space Van 2008, a kite-
assisted SSTO is now posted on http://www.tour2space.com

Is the aerojet engine really so rugged that it can be used for such a long
time without excessive wear? Wouldn't it be better to use some kind of
propeller to reduce engine maintenance?

On the other hand, it would certainly look cool to see a huge box kite
slowly soaring into the stratosphere powered by a large rocket engine.

You could probably write huge sculptures into the sky with the rocket
exhaust while launching it. All that water vapor in such a small area...

good luck with obtaining funding,

Rüdiger

(Oren Tirosh) wrote in message . com...
(Len) wrote in message . com...
Ruediger Klaehn wrote in message news:c7ctt2$2d7g3
...
Have you been working on the newest design from Len Cormier? It looks
similar to something you have proposed a few years ago.

Yes indeed, the concept is in part inspired by inputs from
Pete and Robert Lynn--as implied by the credit to Peter Lynn
Kites on the title page of our presentation at SAS 2004.
There's still a lot of updating needed on our web site;
however, the SAS 2004 presentation: Space Van 2008, a kite-
assisted SSTO is now posted on http://www.tour2space.com

Thanks, I have been waiting eagerly for that presentation to go
online.

I was wondering if the use of dual fuels on the orbiter (LH2+Kerosene)
is essential to this concept. Would it be possible to keep the liftoff
rocket on the kite gondola and use only hydrogen on the orbiter?

If you go through the trouble of handling LH2 anyway it would seem to
make sense to go for the higher Isp and avoid having multiple types of
engines and fuels on board a single vehicle. Was it the density of
kerosene? The unreasonable number of RL10s required to get enough
thrust with hydrogen?

Oren


There are still a lot of tradeoffs that would be useful.
However, we would need a dozen RL10s, if we eliminated
the LOX/kero engine. And, of course, the tripropellant
approach tends to save tankage mass, while still achieving
a relatively high effective specific impulse. Availability
of the RL60 or the MB60 would make an all-hydrogen orbiter
make more sense--while still maintaining a 3-g limit by
cutting engines to stay within throttling limits.

I have to look at parallel burn versus the current series
burn. This would trade off decreased gravity losses for
increased tankage mass. With the kite approach, there are
essentially no drag losses after separation from the kite.

I did look at all LOX/kero. It didn't come close to meeting
performance requirements. Unless, of course, one is into
extreme optimism.

Best regards,
Len (Cormier)
PanAero, Inc.
(change x to len)
http://www.tour2space.com

Ruediger Klaehn wrote in message ...
Len wrote:

[snip]

Have you been working on the newest design from Len Cormier? It looks
similar to something you have proposed a few years ago.

Yes indeed, the concept is in part inspired by inputs from
Pete and Robert Lynn--as implied by the credit to Peter Lynn
Kites on the title page of our presentation at SAS 2004.
There's still a lot of updating needed on our web site;
however, the SAS 2004 presentation: Space Van 2008, a kite-
assisted SSTO is now posted on http://www.tour2space.com

Is the aerojet engine really so rugged that it can be used for such a long
time without excessive wear? Wouldn't it be better to use some kind of
propeller to reduce engine maintenance?

We are assuming a derated engine in deference to maintenance
considerations. Moreover, we do no restart the engine, which
is the main source of cycle fatigue. Another factor is the
lack of coking problems with the Russian hydrocarbon rocket
engines that generally run at a 2.6:1 mixture ratio.

It does take time to climb slowly, but not as long as you
might expect: about 7 minutes, instead of perhaps two or
three minutes to reach the same energy conditions more
rapidly by climbing at much higher dynamic pressure.

Seven minutes is much too short a time to make any
airbreathing engine and propeller pay off. John Hare's
turborocket is interesting, but even that very high thrust-to-
weight engine becomes rapidly unattractive at altitude. I've
always felt that rocket engines are far more effective for
acceleration over a mach range. However, even I am surprised
how appropriate rocket engines are for traversing substantial
altitude ranges. As Pete and Robert Lynn point out, the basic
problem is thrust, not lift, when it comes to kites.

On the other hand, it would certainly look cool to see a huge box kite
slowly soaring into the stratosphere powered by a large rocket engine.

This could be an advantage for tourism flights. Vela tried
hard to extend the pre-boost flight times of their Space Cruiser.

You could probably write huge sculptures into the sky with the rocket
exhaust while launching it. All that water vapor in such a small area...

There's plenty of time to turn. However, it would probably
be very difficult to make more than rather slow-rate turns.
The arrangement is likely to be so stable that we will probably
have to skid the turns.


good luck with obtaining funding,

We shall be addressing the funding problem on our web site
with some unconventional approaches. Moreover, we have
very recently gotten some indication of potential and substantial
outside support. We have had essentially no outside support
up to this time.

Rüdiger

Best regards,
Len (Cormier)
PanAero, Inc.
(change x to len)
http://www.tour2space.com

(Oren Tirosh) wrote in message . com...
(Len) wrote in message . com...
Ruediger Klaehn wrote in message news:c7ctt2$2d7g3
...
Have you been working on the newest design from Len Cormier? It looks
similar to something you have proposed a few years ago.

Yes indeed, the concept is in part inspired by inputs from
Pete and Robert Lynn--as implied by the credit to Peter Lynn
Kites on the title page of our presentation at SAS 2004.
There's still a lot of updating needed on our web site;
however, the SAS 2004 presentation: Space Van 2008, a kite-
assisted SSTO is now posted on http://www.tour2space.com

Thanks, I have been waiting eagerly for that presentation to go
online.

I was wondering if the use of dual fuels on the orbiter (LH2+Kerosene)
is essential to this concept. Would it be possible to keep the liftoff
rocket on the kite gondola and use only hydrogen on the orbiter?

If you go through the trouble of handling LH2 anyway it would seem to
make sense to go for the higher Isp and avoid having multiple types of
engines and fuels on board a single vehicle. Was it the density of
kerosene? The unreasonable number of RL10s required to get enough
thrust with hydrogen?

Oren

Addendum to my earlier response:

In addition to the problem of having to go to perhaps
a dozen RL10 engines, there are significant advantages
to a tripropellant approach besides the saving of tankage
mass for a modest reduction in effective specific impulse.

Hydrogen costs perhaps ten times as much as kerosene.
The difference begins to show up when one tries to achieve
the low recurring cost we expect to achieve. Relative
engine maintenance costs are much more significant, since
engine maintenance is one of the long poles for recurring
costs. Hydrogen engines cost perhaps ten times as much
as LOX/kero engines to acquire and to maintain. Accordingly,
it is worthwhile to use hydrogen power sparingly. Even with
our current concept that uses only four RL10 engines on two
cargo orbiters and two passenger orbiters, hydrogen engine
investment represents perhaps a little more than a third of
our pre-operational investment budget.

Best regards,
Len (Cormier)
PanAero, Inc.
(change x to len)
http://www.tour2space.com

Len wrote:

[snip]
It does take time to climb slowly, but not as long as you
might expect: about 7 minutes, instead of perhaps two or
three minutes to reach the same energy conditions more
rapidly by climbing at much higher dynamic pressure.

Seven minutes is much too short a time to make any
airbreathing engine and propeller pay off.

I agree that airbreathing is probably not worth it, especially since there
is not all that much air to work with at low speed and high altitude.

Something like a rotary-style tip rocket powered propeller would make more
sense. Of course that would be additional complexity, but OTOH you would
not have to design a propellant transfer system from the gondola to the
orbiter.

[snip]
On the other hand, it would certainly look cool to see a huge box kite
slowly soaring into the stratosphere powered by a large rocket engine.

This could be an advantage for tourism flights. Vela tried
hard to extend the pre-boost flight times of their Space Cruiser.

It would certainly help to build suspension before the high-g climb.

[snip]
We shall be addressing the funding problem on our web site
with some unconventional approaches. Moreover, we have
very recently gotten some indication of potential and substantial
outside support. We have had essentially no outside support
up to this time.

You have produced an awful lot of interesting concepts given the lack of
funding. And did you notice that more and more people call their vehicles
space transport instead of that awful three letter acronym?

best regards,

Rüdiger

Ruediger Klaehn wrote in message ...
Len wrote:

[snip]
It does take time to climb slowly, but not as long as you
might expect: about 7 minutes, instead of perhaps two or
three minutes to reach the same energy conditions more
rapidly by climbing at much higher dynamic pressure.

Seven minutes is much too short a time to make any
airbreathing engine and propeller pay off.

I agree that airbreathing is probably not worth it, especially since there
is not all that much air to work with at low speed and high altitude.

Something like a rotary-style tip rocket powered propeller would make more
sense. Of course that would be additional complexity, but OTOH you would
not have to design a propellant transfer system from the gondola to the
orbiter.

A rotary-style tip rocket makes a lot of sense for hover;
I had proposed one for a redeployable, high-capability sonobouy
back in the early 1960's when I was flying P2V's in the reserve.
However, thrust times velocity is a constant for a given
amount of power; accordingly thrust drops off with velocity
and we do get to mach 0.5 or mach 0.55 during the climb.

I envisage propellant transfer to a feed tank in the orbiter
that would be kept filled. An earlier concept would have
put a multitude of tanks in the kite wing--with quite of
few valves. This allowed the orbiter to be tucked up under
the kite wing and still achieve a degree of distributed load.
Most of the wing tanks were actually columns in the truss structure.
However, I think the the kite and suspended gondola is basically
simpler--even though it takes some getting used to.

[snip]
We shall be addressing the funding problem on our web site
with some unconventional approaches. Moreover, we have
very recently gotten some indication of potential and substantial
outside support. We have had essentially no outside support
up to this time.

You have produced an awful lot of interesting concepts given the lack of
funding. And did you notice that more and more people call their vehicles
space transport instead of that awful three letter acronym?

best regards,

Rüdiger

I think that exploratory conceptual design is the
highest payoff way to use limited funds. This is
especially true for "space transports." Even I am
amazed at how much room there is for improvement on
the conceptual level after nearly five decades of
addressing this subject. Exploratory conceptual design
gets shortchanged in today's R&D environment: Phase I
studies tend to define the solution too specifically in
the RFP stage--instead of stating a mission need (as
basically directed by OMB A-109, but generally ignored).
For someone like me, I have to accept the label of being
unfocussed; however, I think the payoff for keeping an
open mind as long as possible is worth the flak. I agree
that at some point--as Dutch Kindelberger used to say--
you have to shoot the engineer and focus on getting a
product out the door. But I see no point of shooting the
engineer prematurely before serious money is being spent.

Best regards,
Len (Cormier)
PanAero, Inc.
(change x to len)
http://www.tour2space.com

Derek Lyons wrote:
(Stefan Dobrev) wrote:

(Derek Lyons) wrote in message news:
Commonly 'low-tech' is interpreted to mean 'cheap and simple'. If
it's *not* cheap and simple, then the technology level is essentially
irrelevant.

You mean building pyramids was high tech, yes?

The only possible ways to interpret what I said as meaning that is to
be on drugs or lacking a forebrain.

Or that you are on drugs or trying to spcificly cofuse the issue by
gross mis-characterisation of the words "high tech" and "low tech".
So far you are the only one i have seen to bring cost of accomplishing
something - and even more claim low tech meant "cheap".

In their day, the pyramids were both the most expensive project of their day
and done by low tech - by both modern and "of their day" standards.


D.

--
Sander

+++ Out of cheese error +++

Karl Hallowell wrote:
On Fri, 07 May 2004 05:30:27 -0700, Stefan Dobrev wrote:

(Derek Lyons) wrote in message
...
Commonly 'low-tech' is interpreted to mean 'cheap and simple'. If it's
*not* cheap and simple, then the technology level is essentially
irrelevant.
You mean building pyramids was high tech, yes?

snip

At the time, the pyramids were very high tech requiring skills, knowledge,
and of course, sophisticated organization that most of humanity couldn't
manage. And obviously they weren't cheap and simple.


Wrong. Pyramids are the classical example of spenindg a lot of time and effort
on a low tech project (with good results, one might add). But they are a very
bad thing to measure the sophistication of egyptians by.


Karl Hallowell


--
Sander

+++ Out of cheese error +++

Sander Vesik wrote:

Derek Lyons wrote:
(Stefan Dobrev) wrote:

(Derek Lyons) wrote in message news:
Commonly 'low-tech' is interpreted to mean 'cheap and simple'. If
it's *not* cheap and simple, then the technology level is essentially
irrelevant.

You mean building pyramids was high tech, yes?

The only possible ways to interpret what I said as meaning that is to
be on drugs or lacking a forebrain.

Or that you are on drugs or trying to spcificly cofuse the issue by
gross mis-characterisation of the words "high tech" and "low tech".

In common parlance 'low-tech' almost always is shorthand for 'cheap
and simple'. This isn't gross mischaracterization, but a simple
statement of fact.

So far you are the only one i have seen to bring cost of accomplishing
something - and even more claim low tech meant "cheap".

Because I am the only one, seemingly, interested in actually
accomplishing something with this prize. I'm holding it to the same
standards as other alternative acess projects; that of reducing costs.
(Or to put it simpler, I'm thinking about the whole picture.)

In their day, the pyramids were both the most expensive project of their day
and done by low tech - by both modern and "of their day" standards.

ROTFLMAO. The Pyramids couldn't be built by low tech means *today*,
let alone 3000 years ago. You must mean the Pyramids on some
alternate timeline.

D.
--
Touch-twice life. Eat. Drink. Laugh.