Reentry prize?

Jochem Huhmann wrote:

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.

I find that highly unlikely. The DARPA grand challenge also had quite low
entry requirements, but there were only ~30 serious teams.

But even if this were the case, you could sort out most of the bad ones by
just dropping them out of an aircraft or shaking them to shreds on a
vibration test stand.

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.

You only have to test the vehicles that survive the drop tests from an
airplane. And of course you do the less expensive tests first to minimize
the test costs.

The drop tests seem useless, too.

The drop tests are a cheap and fun way to sort out the serious competitors.
Repeat until there are only 10 vehicles left. Then do the more expensive
tests with the remaining vehicles only.

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.

You would probably have a standard payload container that protects the
reentry vehicles from each other and separates them. Such systems already
exist for secondary payloads on large launch vehicles.

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.

Yes, of course there needs to be some minimum payload fraction. I forgot to
mention this because I thought it was obvious.

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.

A falcon I is 5.9 million $ plus range costs. When you give that kind of
money to a large aerospace contractor, you are lucky to get some powerpoint
slides.

Ruediger Klaehn writes:
The drop tests are a cheap and fun way to sort out the serious competitors.
Repeat until there are only 10 vehicles left. Then do the more expensive
tests with the remaining vehicles only.

Drop tests are surely somewhat cheap and funny, but they don't tell
much about how the vehicle is able to withstand reentry...

You would probably have a standard payload container that protects the
reentry vehicles from each other and separates them. Such systems already
exist for secondary payloads on large launch vehicles.

Yes, but systems to integrate, restrain and deploy 10 or more vehicles
on a not so large launcher are not exactly off-the-shelf hardware. OK,
ICBM's may have something like that already, but probably not those you
can get your hands at.

Yes, of course there needs to be some minimum payload fraction. I forgot to
mention this because I thought it was obvious.

It is obvious, but setting a reasonable fraction is not too easy,
especially with relatively small absolute masses. Allow too much mass
for reentry and landing systems, and the developed systems won't be that
useful for larger vehicles. Allow too less mass for that and more
sophisticated systems become impossible, you will almost surely end up
with ablative heatshields.

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.

A falcon I is 5.9 million $ plus range costs. When you give that kind of
money to a large aerospace contractor, you are lucky to get some powerpoint
slides.

A Falcon I has 670kg payload to a 200km orbit. I do not know how this
translates into a suborbital trajectory with sufficient reentry speeds
for such a mission, but let's say it's 2000 kg (if this is still within
the envelope of the Falcon, which I doubt). Further let's assume 100kg
vehicles and another 100kg per vehicle for a payload container,
separation mechanisms, restrains, structure and so on. Now we have room
on the laucher for 10 of such vehicles (10 x (100 + 100)), each costing
roughly half a million just for the launch. Add development costs for
the payload structure and deployment/separation system, lots of tests
for sieving out competitors and each competitor will cost at least a
couple of millions. Then of course there will be the prize itself and
soon all these millions add up to real money.

OK, I could think of an application where this could have a direct use:
Microsats with a return-capability. If there is a market for those,
successful competitors could get a stand in this market instantly.


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

Jochem Huhmann wrote:

Ruediger Klaehn writes:
The drop tests are a cheap and fun way to sort out the serious
competitors. Repeat until there are only 10 vehicles left. Then do the
more expensive tests with the remaining vehicles only.

Drop tests are surely somewhat cheap and funny, but they don't tell
much about how the vehicle is able to withstand reentry...

Of course not. Reentry can not be simulated that easily. But it tells
something about the ability of the group to build a working autonomous
vehicle.

You would probably have a standard payload container that protects the
reentry vehicles from each other and separates them. Such systems already
exist for secondary payloads on large launch vehicles.

Yes, but systems to integrate, restrain and deploy 10 or more vehicles
on a not so large launcher are not exactly off-the-shelf hardware. OK,
ICBM's may have something like that already, but probably not those you
can get your hands at.

The problem is much less complicated than with satellites or warheads. You
don't need to put the RVs in a precise orbit in a precise orientation. You
just need to separate them somehow. And space debris creation is not a
problem since you are in a suborbital trajectory. The RVs are also much
more rugged than typical satellites, so a rough separation should not be a
problem.

[snip]
A falcon I is 5.9 million $ plus range costs. When you give that kind of
money to a large aerospace contractor, you are lucky to get some
powerpoint slides.

A Falcon I has 670kg payload to a 200km orbit. I do not know how this
translates into a suborbital trajectory with sufficient reentry speeds
for such a mission, but let's say it's 2000 kg (if this is still within
the envelope of the Falcon, which I doubt). Further let's assume 100kg
vehicles and another 100kg per vehicle for a payload container,
separation mechanisms, restrains, structure and so on. Now we have room
on the laucher for 10 of such vehicles (10 x (100 + 100)), each costing
roughly half a million just for the launch. Add development costs for
the payload structure and deployment/separation system, lots of tests
for sieving out competitors and each competitor will cost at least a
couple of millions. Then of course there will be the prize itself and
soon all these millions add up to real money.

Yes, it is serious money for you and me. But for NASA or DARPA or the USAF
~20 million $ is not that much. DARPA has spent more than 10 million $ on
the grand challenge, and they are willing to spend more. It was still a
good deal for them since many teams have invested substantial money and
lots of unpaid work in the vehicles. I think the red team alone has spent
more than the prize of 1 million $ on their hardware.

Ruediger Klaehn wrote:
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.

Commonly 'low-tech' is interpreted to mean 'cheap and simple'. If
it's *not* cheap and simple, then the technology level is essentially
irrelevant.

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

Jochem Huhmann wrote:

You would probably have a standard payload container that protects the
reentry vehicles from each other and separates them. Such systems already
exist for secondary payloads on large launch vehicles.

Yes, but systems to integrate, restrain and deploy 10 or more vehicles
on a not so large launcher are not exactly off-the-shelf hardware. OK,
ICBM's may have something like that already, but probably not those you
can get your hands at.

ICBM's have 'something like that', yes. But they are designed to
handle a standard payload. What Ruediger is proposing is (AIUI) a
standard 'can' with custom hardware inside it for each RV to be
tested, expensive and messy.

Far better to specify a standard 'can' and mounting interface and make
it the responsibility of the competitor to meet that standard.

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

Ruediger Klaehn wrote:
Drop tests are surely somewhat cheap and funny, but they don't tell
much about how the vehicle is able to withstand reentry...

Of course not. Reentry can not be simulated that easily. But it tells
something about the ability of the group to build a working autonomous
vehicle.

That can be determined by fairly simple ground tests, no need for
something as silly as the drop testing. (Especially considering that
any serious team will have already done that testing.) The DARPA Grand
Challenge was a joke because the set a specification well beyond that
what was reasonably achievable and on a timeline much shorter than
anything approaching rational. Then they ran the test *anyhow*, and
produced what amounted to a massive no-test at great expense and
complication.

The problem is much less complicated than with satellites or warheads. You
don't need to put the RVs in a precise orbit in a precise orientation.

ROTFL. Yes, you *do* need a fairly precise orbit, unless dropping
RV's in the wrong place entirely is something you find desirable. ( I
assure you that your insurance company doesn't.) Furthermore, without
a reasonably precise trajectory you cannot predict (in advance) that
each RV will experience a trajectory that creates the desired test
environment.

You just need to separate them somehow.

Yah. 'Somehow' that is both predictable, and cheap, and simple, and
does not produce interference between the units under test. A tall
order.

The RVs are also much more rugged than typical satellites, so a rough
separation should not be a problem.

ROTFL.

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

Ruediger Klaehn wrote:


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.


First off, "Chinese Heat Shield" would be a great name for a cocktail in
some type; probably one that's on fire when they bring it to you. If you
don't want it on fire, then it's a "Chinese Fire Drill".
Second, according to this it's made out of ablative impregnated oak:
http://www.astronautix.com/craft/fsw.htm

Pat

Thinking about Ruediger's proposal, I find a near fatal flaw if the
goal is to encourage the development of new re-entry and TPS schemes.
He requires that the individual teams develop their own complete
vehicles, which means they must gather expertise far outside that of
simply TPS, and raises the barrier to entry.

If I were running this contest, I'd develop a 'standard' capsule, onto
which the candidate TPS could be attached. Obviously, this won't work
for all possible corners of the solution space, but should work for a
large number of them. Imagine something like an Apollo or Soyuz
capsule with the control and recovery equipment concentrated into the
upper half of the capsule. The lower half could be ballasted and/or
used for the TPS support systems, (for the more exotic means like
water cooled etc.).

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

I am not sure if reentry and landing can really be separated and pursued
in isolation, too many unnatural distortions. Also, you do not want to
be paying for launches, if you do have to pay for this, it should be
another prize, two birds one stone.

Other than the obvious follow ons from the X-Prize, another launch prize
system I have contemplated is the development of a 10kg class launch
vehicle. Say $10 million distributed equally among the number of
successful launches each year. I think an ongoing prize is required for
serious development, allowing a continuous program that learns from
mistakes. The prize value per launch would reduce as flight rates
increased. Income could be supplemented by the carrying of commercial
payloads, say from Universities, commercial interests, people wanting to
test reentry and landing systems, etc. This would also serve to develop
a launch market, an almost essential component of a good prize system.

I would expect most groups to purchase high altitude air launches off
some external group, White Knight for example, though I expect there are
far cheaper alternatives. There are significant advantages in high
altitude launches at this scale, though this would obviously be a choice
left to the individuals. I would also expect a great deal of
commonality in the various components used by various groups, in effect
groups might set themselves up as developers and suppliers of various
components to all the competing groups, engines for example, might
effectively become OTS.

Such a prize might almost be within the grasp of small hobby type
groups, and all approaches from MCD to SSTO could be tested in the
market place at the lowest possible cost. The 10kg constraint is
required so as to maximize flight rate. Groups might launch larger
vehicles than this, but only be paid at this rate.

Once there was a degree of design convergence, and the market had proven
itself you might then move on to a larger payload prize system. Though
I expect this would not be required as the market and technologies would
by then be sufficiently developed that larger commercial interests would
takeover.

Pete.


"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

On Wed, 05 May 2004 19:55:10 GMT, in a place far, far away,
(Derek Lyons) made the phosphor on my
monitor glow in such a way as to indicate that:

Thinking about Ruediger's proposal, I find a near fatal flaw if the
goal is to encourage the development of new re-entry and TPS schemes.
He requires that the individual teams develop their own complete
vehicles, which means they must gather expertise far outside that of
simply TPS, and raises the barrier to entry.

If I were running this contest, I'd develop a 'standard' capsule, onto
which the candidate TPS could be attached. Obviously, this won't work
for all possible corners of the solution space, but should work for a
large number of them. Imagine something like an Apollo or Soyuz
capsule with the control and recovery equipment concentrated into the
upper half of the capsule. The lower half could be ballasted and/or
used for the TPS support systems, (for the more exotic means like
water cooled etc.).

It depends on whether the purpose of the prize is to develop TPS
materials, or entry vehicles. The latter would be more useful, but
more complex.