DARPA's Hot Rod

Hello all:

DARPA's working on a Space Plane that could deliver a 2000lb payload to
2500nm, or put a smaller payload into orbit. See:

http://aviationnow.com/avnow/news/ch...s/09223top.xml

Many low-cost space launch concepts have been proposed over the years.
How practical is this one?

On 23 Sep 2003 20:52:00 -0700, (Eric Moore)
wrote:

Hello all:

DARPA's working on a Space Plane that could deliver a 2000lb payload to
2500nm, or put a smaller payload into orbit. See:

http://aviationnow.com/avnow/news/ch...s/09223top.xml

Many low-cost space launch concepts have been proposed over the years.
How practical is this one?


the thing I'm wondering is if they build it would the additional
goodies in the intakes bar it from taking a whole slew of time to
altitude, speed, and sustained altitude records. FOUR F100s (likely
-229s) with SEA LEVEL power at 100,000 feet in an 80,000lb aircraft
(below sixty if you leave the payload out and don't go full fuel).
The mind boggles.

"Hobo" wrote in message

Many low-cost space launch concepts have been proposed over
the years.
How practical is this one?

During one of the threads concerning whether or not the F-22 could go
past mach 2 without variable inlets someone mentioned the possibility
of injecting water into the airflow and said that this had been
previously tested on a F-4 which got past mach 2.5 using the system.
If I
understood the article correctly they are going to try and use a
similar system.

As to the space-launch issue, I think you have to get up to around
mach 25 to enter into a stable orbit and I don't see how this system
is going to get you going that fast.

The air-breathing vehicle doesn't get anywhere close to that fast. The
expendable rocket upper stage adds the oomph to get the (very small) payload
rom 200,000 ft into orbit. Note that the reusable air vehicle carries
16,000 lbs of rocket aloft to put a total of 110 pounds into orbit. One
might profitably ask whether you gain a whole lot by not simply putting the
expendable upper stage on an expendable lower stage and launching the stack
from a pad somewhere. The savings sources offered seem questionable to me
and some could be used by a conventional expendable anyway.

The other real problem here is that the whole concept is premised on being
able to get a useful reconaissance payload (what else needs to be
sun-synchronous?) into a 110-lb package. I'm not holding my breath.

--�
Tom Schoene Replace "invalid" with "net" to e-mail
"If brave men and women never died, there would be nothing
special about bravery." -- Andy Rooney (attributed)

The other real problem here is that the whole concept is premised on being
able to get a useful reconaissance payload (what else needs to be
sun-synchronous?) into a 110-lb package. I'm not holding my breath.

--?
Tom Schoene Replace "invalid" with "net" to e-mail
"If brave men and women never died, there would be nothing
special about bravery." -- Andy Rooney (attributed)




I wonder what else it could be used for. Take out the payload and add
say 13,000lbs of fuel and 3000lbs of SDBs. Or how bout 6000lbs of
fuel and four SDBs with 2000lb solid boosters on them. Launched at
Mach 3 how fast could 2000lbs of rocket propellent get an SDB? At
100,000ft how far would it go?

On Thu, 25 Sep 2003 00:26:03 -0600, Scott Ferrin
wrote:


The other real problem here is that the whole concept is premised on being
able to get a useful reconaissance payload (what else needs to be
sun-synchronous?) into a 110-lb package. I'm not holding my breath.

--?
Tom Schoene Replace "invalid" with "net" to e-mail
"If brave men and women never died, there would be nothing
special about bravery." -- Andy Rooney (attributed)




I wonder what else it could be used for. Take out the payload and add
say 13,000lbs of fuel and 3000lbs of SDBs. Or how bout 6000lbs of
fuel and four SDBs with 2000lb solid boosters on them. Launched at
Mach 3 how fast could 2000lbs of rocket propellent get an SDB? At
100,000ft how far would it go?


Come to think of it it would make a good ASAT weapon too. With a
booster that big it could probably hit stuff clear up in geostationary
orbit.

Scott Ferrin wrote in message . ..
On Thu, 25 Sep 2003 00:26:03 -0600, Scott Ferrin
wrote:


The other real problem here is that the whole concept is premised on being
able to get a useful reconaissance payload (what else needs to be
sun-synchronous?) into a 110-lb package. I'm not holding my breath.

--?
Tom Schoene Replace "invalid" with "net" to e-mail
"If brave men and women never died, there would be nothing
special about bravery." -- Andy Rooney (attributed)




I wonder what else it could be used for. Take out the payload and add
say 13,000lbs of fuel and 3000lbs of SDBs. Or how bout 6000lbs of
fuel and four SDBs with 2000lb solid boosters on them. Launched at
Mach 3 how fast could 2000lbs of rocket propellent get an SDB? At
100,000ft how far would it go?


Come to think of it it would make a good ASAT weapon too. With a
booster that big it could probably hit stuff clear up in geostationary
orbit.


How much would performance be improved if hybrids using newer paraffin-
based propellants

http://thomasc.stanford.edu/research.html

were used in place of the existing hybrid motor?

On 29 Sep 2003 21:34:46 -0700, (Eric Moore)
wrote:

Scott Ferrin wrote in message . ..
On Thu, 25 Sep 2003 00:26:03 -0600, Scott Ferrin
wrote:


The other real problem here is that the whole concept is premised on being
able to get a useful reconaissance payload (what else needs to be
sun-synchronous?) into a 110-lb package. I'm not holding my breath.

--?
Tom Schoene Replace "invalid" with "net" to e-mail
"If brave men and women never died, there would be nothing
special about bravery." -- Andy Rooney (attributed)




I wonder what else it could be used for. Take out the payload and add
say 13,000lbs of fuel and 3000lbs of SDBs. Or how bout 6000lbs of
fuel and four SDBs with 2000lb solid boosters on them. Launched at
Mach 3 how fast could 2000lbs of rocket propellent get an SDB? At
100,000ft how far would it go?


Come to think of it it would make a good ASAT weapon too. With a
booster that big it could probably hit stuff clear up in geostationary
orbit.


How much would performance be improved if hybrids using newer paraffin-
based propellants

http://thomasc.stanford.edu/research.html

were used in place of the existing hybrid motor?


Beats the hell out of me. You'd need the ISP of the two different
propellants/ engines and run the numbers.