A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Space Science » Policy
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Reentry prize?



 
 
Thread Tools Display Modes
  #1  
Old May 4th 04, 03:28 PM
Ruediger Klaehn
external usenet poster
 
Posts: n/a
Default Reentry prize?

After the claiming of the X-Prize (hopefully) this year, and with the NASA
centennial challenges program, there is some need for new ideas for
aerospace prizes. One very simple upgrade to the X-Prize idea would be an
upgraded X-Prize with a significant downrange component.

But there is another area of space flight that is really unexplored and has
the potential for very high gains with comparatively low investments:
reentry and landing. There are numerous interesting concepts for reentry,
and most of them have never been tried (this is what NASA should have been
doing!).

Just to name a few: exotic metallic heat shields, exotic ceramic heat
shields, cheap ablative heat shields, water cooled heat shields, heat sink
heat shields, very large hypersonic drogue chutes, hypersonic parawings,
light inflatable heat shields, large unfolding radiatively cooled metallic
heat shields etc.

What about this idea for a new aerospace price: participants get a payload
of a defined mass (e.g. 100kg) and volume (e.g. 1m^3), and the objective of
the prize is to soft-land as much as possible of the mass from orbital
velocity.

Put in some eggs, and they should be neither cooked nor broken :-)

To sort out serious competitors, you would first do multiple drop tests from
low altitude. This can be very cheap by using a military transport plane.

Then you do one or two high altitude drop test from a stratospheric ballon
at 30km altitude or from an X-Price vehicle at 100km altitude.

All competitors whose reentry vehicles survive these initial tests are given
a free ride to orbit with a low-cost launch vehicle such as falcon, an old
(russian?) ICBM or as a secondary payload on a large launch vehicle.

The most practical approach would probably be to use a falcon I or an old
ICBM to get ~10 reentry vehicles in an almost orbital trajectory and to
separate them. Then they would be on their own and would have to survive
reentry and landing. Additional points could be given for hitting a
precalculated point downrange and for crossrange.

The barrier of entry for such a price would be very low, as demonstrated by
the wooden heat shields on some chinese capsules. So among the potential
participants would be universities, companies that want to demonstrate
their reentry technology and probably also non-profit organisations and
individuals.

Of course the exact requirements for this price would have to be worked out,
but I think the basic idea has some merit. With propulsion prizes, the
barrier of entry is very high, and no amount of ingenuity will get the ISP
of a hydrocarbon engine above 400s and the ISP of a LOX/LH2 engine above
500s. With reentry, the barrier of entry is comparatively low (a "starter
kit" would be an aerodynamically stable capsule with a wood heat shield, a
barometer and a parachute) and the potential gains are huge.

So what do you think?

best regards,

Rüdiger
  #2  
Old May 4th 04, 10:01 PM
JimO
external usenet poster
 
Posts: n/a
Default Reentry prize?

A great idea -- I second the mo!


"Ruediger Klaehn" wrote in message
...
After the claiming of the X-Prize (hopefully) this year, and with the NASA
centennial challenges program, there is some need for new ideas for
aerospace prizes. One very simple upgrade to the X-Prize idea would be an
upgraded X-Prize with a significant downrange component.

But there is another area of space flight that is really unexplored and

has
the potential for very high gains with comparatively low investments:
reentry and landing. There are numerous interesting concepts for reentry,
and most of them have never been tried (this is what NASA should have been
doing!).

Just to name a few: exotic metallic heat shields, exotic ceramic heat
shields, cheap ablative heat shields, water cooled heat shields, heat sink
heat shields, very large hypersonic drogue chutes, hypersonic parawings,
light inflatable heat shields, large unfolding radiatively cooled metallic
heat shields etc.

What about this idea for a new aerospace price: participants get a payload
of a defined mass (e.g. 100kg) and volume (e.g. 1m^3), and the objective

of
the prize is to soft-land as much as possible of the mass from orbital
velocity.

Put in some eggs, and they should be neither cooked nor broken :-)

To sort out serious competitors, you would first do multiple drop tests

from
low altitude. This can be very cheap by using a military transport plane.

Then you do one or two high altitude drop test from a stratospheric ballon
at 30km altitude or from an X-Price vehicle at 100km altitude.

All competitors whose reentry vehicles survive these initial tests are

given
a free ride to orbit with a low-cost launch vehicle such as falcon, an old
(russian?) ICBM or as a secondary payload on a large launch vehicle.

The most practical approach would probably be to use a falcon I or an old
ICBM to get ~10 reentry vehicles in an almost orbital trajectory and to
separate them. Then they would be on their own and would have to survive
reentry and landing. Additional points could be given for hitting a
precalculated point downrange and for crossrange.

The barrier of entry for such a price would be very low, as demonstrated

by
the wooden heat shields on some chinese capsules. So among the potential
participants would be universities, companies that want to demonstrate
their reentry technology and probably also non-profit organisations and
individuals.

Of course the exact requirements for this price would have to be worked

out,
but I think the basic idea has some merit. With propulsion prizes, the
barrier of entry is very high, and no amount of ingenuity will get the ISP
of a hydrocarbon engine above 400s and the ISP of a LOX/LH2 engine above
500s. With reentry, the barrier of entry is comparatively low (a "starter
kit" would be an aerodynamically stable capsule with a wood heat shield, a
barometer and a parachute) and the potential gains are huge.

So what do you think?

best regards,

Rüdiger



  #3  
Old May 4th 04, 11:20 PM
Derek Lyons
external usenet poster
 
Posts: n/a
Default Reentry prize?

Ruediger Klaehn wrote:

The barrier of entry for such a price would be very low, as demonstrated by
the wooden heat shields on some chinese capsules.


Hmm... No.

Unless the Chinese are doing something *very* different from others in
the past, the wood is carefully chosen (no knots!), carefully formed,
and carefully prepared to meet specific density and performance
characteristics.

Not particularly easy, nor likely much cheaper than other methods.

D.
--
Touch-twice life. Eat. Drink. Laugh.
  #4  
Old May 4th 04, 11:42 PM
Ruediger Klaehn
external usenet poster
 
Posts: n/a
Default Reentry prize?

Derek Lyons wrote:

Ruediger Klaehn wrote:

The barrier of entry for such a price would be very low, as demonstrated
by the wooden heat shields on some chinese capsules.


Hmm... No.

Unless the Chinese are doing something *very* different from others in
the past, the wood is carefully chosen (no knots!), carefully formed,
and carefully prepared to meet specific density and performance
characteristics.

Of course you can not just slap a wooden board to the base of your capsule.
For optimum effect you will probably have the pores pointing downward. But
a wooden heat shield is nevertheless a low-tech approach that is doable for
an amateur group or an university.

I am not saying that wooden heat shields are the best solution. In fact, I
don't know what the best solution is. But that is what the prize is
supposed to find out.
  #5  
Old May 5th 04, 02:14 AM
Derek Lyons
external usenet poster
 
Posts: n/a
Default Reentry prize?

Ruediger Klaehn wrote:

Derek Lyons wrote:

Ruediger Klaehn wrote:


The barrier of entry for such a price would be very low, as demonstrated
by the wooden heat shields on some chinese capsules.


Hmm... No.
Unless the Chinese are doing something *very* different from others in
the past, the wood is carefully chosen (no knots!), carefully formed,
and carefully prepared to meet specific density and performance
characteristics.

Of course you can not just slap a wooden board to the base of your capsule.
For optimum effect you will probably have the pores pointing downward. But
a wooden heat shield is nevertheless a low-tech approach that is doable for
an amateur group or an university.


I see no evidence that it is a low tech approach. Don't confuse
simplicity of approach and (misleadingly) apparent simplicity of
material with low tech and low cost.

I am not saying that wooden heat shields are the best solution. In fact, I
don't know what the best solution is. But that is what the prize is
supposed to find out.


No one is addressing the question of what constitutes the best
approach. We are instead considering the question of whether or not a
wooden heat shield is in fact cheap or simple.

D.
--
Touch-twice life. Eat. Drink. Laugh.
  #8  
Old May 5th 04, 10:26 AM
Ruediger Klaehn
external usenet poster
 
Posts: n/a
Default Reentry prize?

Derek Lyons wrote:

Ruediger Klaehn wrote:

[snip]

I am not saying that wooden heat shields are the best solution. In fact, I
don't know what the best solution is. But that is what the prize is
supposed to find out.


No one is addressing the question of what constitutes the best
approach. We are instead considering the question of whether or not a
wooden heat shield is in fact cheap or simple.

I never said that building a wooden heat shield is cheap or simple. In fact
it is probably quite expensive with western labor costs since it requires a
lot of manual labor for assembly and quality control.

But it is still a low-tech approach compared to almost anything else that
has been suggested for heat shields.

Since we do not know the exact design of the chinese heat shield there is no
way we can find out who is right, so we might as well end the discussion.
  #9  
Old May 5th 04, 11:35 AM
Ruediger Klaehn
external usenet poster
 
Posts: n/a
Default Reentry prize?

Tom Merkle wrote:

[snip]
I think it's a great idea, although I have some serious doubts about
any NASA-led selection process for 'finalists.'

I think there should be no selection process except the drop tests. If you
have a selection process that is not based on actual flights, it is not a
good prize.

So if you have too many competitors, just repeat the drop tests until some
competitors fail. Or put them on a vibration table for launch simulation or
in a vacuum chamber for space simulation.

But I don't think that this will be a problem. For the X-Prize there are
only a few (definitely less than 10) participants that have a decent chance
of winning. And with the DARPA grand challenge, most participants failed
within the first mile.

I would expect maybe 20 or 30 teams to show up for the airplane drop tests.
Since they will probably have done some airplane drop tests on their own,
most reentry vehicles will survive this. But the high altitude drop tests
where the vehicles will reach supersonic speed will result in many craters
in the ground and only a few remaining teams.
  #10  
Old May 5th 04, 12:43 PM
Jochem Huhmann
external usenet poster
 
Posts: n/a
Default Reentry prize?

Ruediger Klaehn writes:

I would expect maybe 20 or 30 teams to show up for the airplane drop tests.
Since they will probably have done some airplane drop tests on their own,
most reentry vehicles will survive this. But the high altitude drop tests
where the vehicles will reach supersonic speed will result in many craters
in the ground and only a few remaining teams.


I feel the problem with your scheme is that the competitors don't have
to pay for the launch. So why not go and try something. You would
probably have thousands of teams. So you have the competitors make to
pay for the launch. But now you have to make sure that their vehicles
actually get a chance to accomplish their mission, which at least means
testing *all* vehicles on the laucher to be launch-, space- and
separation-ready. Which means vibration-, vacuum-, temperature-,
outgassing- and whatnot tests.

The drop tests seem useless, too. The first problem with building such a
reentry vehicle is to build one that a) does survive launch, b) does not
endanger the launcher and the other vehicles on the same laucher even
when it fails and c) is able to separate from the launcher without
shredding itself and the competiting vehicles into tiny
pieces. Everything you can test with a drop test is the easiest part of
all.

Furthermore, being able to build a 100kg/1m^3 vehicle with no (or very
little) actual payload is irrelevant to the problem at hand. Building a
vehicle that has an order of magnitude more mass for heatshield and
landing mechamisms than for payload is certainly not helping in
developing *useful* new ways of reentry. The hard part in reentry is to
do it with a large payload fraction.

If you'd say "80kg of the 100kg has to be payload" this gets more
useful. After all noone is keen on new ways to build a craft that has,
say, 3 tons of capsule wrapped in 300 tons of heatshield.

Anyway, I think your idea is not bad, but alone the launch looks like a
major and expensive mission -- deploying a bunch of vehicles from a
launcher, all prototypes, all different actually is a nightmare from a
planning point of view.


Jochem

--
"A designer knows he has arrived at perfection not when there is no
longer anything to add, but when there is no longer anything to take
away." - Antoine de Saint-Exupery
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Wednesday, Sep 29 -- the first SpaceShipOne flight in a two-part try at the X-Prize. Jim Oberg Space Shuttle 0 July 27th 04 10:09 PM
Nose first reentry on winged vehicles David Findlay Space Shuttle 2 July 25th 04 02:14 AM
A "Z" Prize to Luna? Allen Meece Policy 2 November 4th 03 02:15 AM
Orbital Reentry shield/landing system? Ian Woollard Technology 14 October 3rd 03 10:25 PM


All times are GMT +1. The time now is 08:35 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.