Darpa Revives Larger Reusable Booster Spaceplane

"The U.S. Defense Advanced Research Projects Agency (Darpa) plans to
seek industry interest next month in an Experimental Spaceplane (XS-1)
which will be capable of delivering a payload up to 5,000 lb. to space
for less than $5 million per launch.

The XS-1 is targeted at flying at Mach 10 plus and generating a sortie
rate of up to 10 times over 10 days. The program compliments the
agency’s ongoing Airborne Launch Assist Space Access (Alasa) program,
which is developing an air launch system for small satellites, and
appears to be a partial revival of the Air Force Research Laboratory’s abandoned Reusable Booster System (RBS) Pathfinder.

Like RBS, the XS-1 would be based on a hypersonic first stage which would
deliver payloads to low Earth orbit via one or more expendable stages.
The first stage would return autonomously to the launch site for reuse.
Darpa, which is expected to issue a Broad Agency Announcement for XS-1
shortly, says “modular components, durable thermal protection systems and
automatic launch, flight, and recovery systems should significantly reduce
logistical needs, enabling rapid turnaround between flights.”

See:

http://www.aviationweek.com/Article...._p0-618115.xml

On Saturday, September 21, 2013 8:41:49 AM UTC+12, wrote:
"The U.S. Defense Advanced Research Projects Agency (Darpa) plans to

seek industry interest next month in an Experimental Spaceplane (XS-1)

which will be capable of delivering a payload up to 5,000 lb. to space

for less than $5 million per launch.



The XS-1 is targeted at flying at Mach 10 plus and generating a sortie

rate of up to 10 times over 10 days. The program compliments the

agency’s ongoing Airborne Launch Assist Space Access (Alasa) program,

which is developing an air launch system for small satellites, and

appears to be a partial revival of the Air Force Research Laboratory’s abandoned Reusable Booster System (RBS) Pathfinder.



Like RBS, the XS-1 would be based on a hypersonic first stage which would

deliver payloads to low Earth orbit via one or more expendable stages.

The first stage would return autonomously to the launch site for reuse.

Darpa, which is expected to issue a Broad Agency Announcement for XS-1

shortly, says “modular components, durable thermal protection systems and

automatic launch, flight, and recovery systems should significantly reduce

logistical needs, enabling rapid turnaround between flights.”



See:



http://www.aviationweek.com/Article...._p0-618115.xml

Consider a capsule that is a frustrum

2.5 ft hatch
9.8 ft base
8.1 ft height

Within this volume is carried 5,000 lbs of payload. The base of the cone consists of a zero height aerospike nozzle with MEMS based rocket array at the rim. The plug doubles as a heat sheild. There is a 2.5 ft diameter by 45.0 ft tall cylinder with a spherical nose cone. There are six tanks that when assembled around the hatch tank form a cone 45.0 ft tall and 9.0 ft in diameter.

The cone, along with the hatch tank and six segment tanks each mass 1,000 lbs. Each tank carries 12,187 lbs of propellant. 1,875 lbs of hydrogen 10,312 lbs of oxygen. All tanks feed the central aerospike engine.

During loading the six segment tanks can be raised 8.0 feet above the base of the cone by a pneumatic cylinder built into the hatch tank. This aids in loading and unloading the cone. A single point of loading all tanks for each propellant exists near the base of the cone.

At lift off the narrow biconical shape blasts off with propellant being drained from four of the seven tanks. When empty they are dropped, slow to sub-sonic speed and fly back to the launch center for landing using air breathing engines.

Meanwhile the cone with three tanks remaining continues skyward. This time two of the segment tanks are being drained to feed the aerospike engine. When drained these too are dropped, and re-enter. They slow to subsonic speed and deploy an inflatable wing along with air breathing MEMS jets, running on excess hydrogen in the propellant tank. This system too flies back to the launch center for recovery.

Meanwhile the cone with a single hatch tank remains and continues skyward. This time the hatch tank is feeding the capsule, which supplies the capsule nearly all the way to orbit. The hatch tank is ejected and drops back to Earth near the launch center, deploys an inflatable wing after slowing to subsonic speed, and lands at the launch center.

Meanwhile, the cone circularizes its orbit, and carries out its mission before returning to Earth and recovery at the launch center by parachute.

On 9/20/2013 4:41 PM, wrote:
"The U.S. Defense Advanced Research Projects Agency (Darpa) plans to
seek industry interest next month in an Experimental Spaceplane (XS-1)
which will be capable of delivering a payload up to 5,000 lb. to space
for less than $5 million per launch.

What I find most interesting about this article is who is NOT mentioned.
SpaceX and Stratolaunch.

Esp. noticeable is no mention of SpaceX which has already been running
its "Grasshopper" test series. Even though in the article it states:

/quote
The initiative was unveiled at the recent Space 2013 conference in San
Diego by Darpa Tactical Technology Office Deputy Director Pam Melroy.
Although the agency has released artist’s impressions of winged XS-1
concepts, Melroy emphasizes the goal is reusability and the method of
achieving that is up to interested parties. Darpa also believes that
some reusable technology features of the Alasa contenders could also
feature in the larger capacity XS-1. The agency has awarded Alasa
concept study contracts to Boeing, Lockheed Martin and Virgin Galactic,
as well as separate technology development contracts to other contenders.
/end-quote

It will be interesting to see if the mentioned players can actually meet
those cost targets given their history...

Also curious to see VG given mention. None of the mentioned players have
hardware anywhere close to what SpaceX has. The omission is glaring.
What is DARPA's *real* intent? A viable second source? Since apparently
the qualification for receiving a "study" contract is a good PowerPoint
presentation.

The $5 million figure is also interesting. Why that figure DARPA? I
remember reading SpaceX's goal was $10 million / launch. Which is
already an order of magnitude below where we are today. Wassup DARPA?
$10M not good enough for ya?

Dave

On Sat, 21 Sep 2013 21:01:03 -0400, David Spain
wrote:

On 9/20/2013 4:41 PM, wrote:
"The U.S. Defense Advanced Research Projects Agency (Darpa) plans to
seek industry interest next month in an Experimental Spaceplane (XS-1)
which will be capable of delivering a payload up to 5,000 lb. to space
for less than $5 million per launch.

What I find most interesting about this article is who is NOT mentioned.
SpaceX and Stratolaunch.

Esp. noticeable is no mention of SpaceX which has already been running
its "Grasshopper" test series. Even though in the article it states:

/quote
The initiative was unveiled at the recent Space 2013 conference in San
Diego by Darpa Tactical Technology Office Deputy Director Pam Melroy.
Although the agency has released artist’s impressions of winged XS-1
concepts, Melroy emphasizes the goal is reusability and the method of
achieving that is up to interested parties. Darpa also believes that
some reusable technology features of the Alasa contenders could also
feature in the larger capacity XS-1. The agency has awarded Alasa
concept study contracts to Boeing, Lockheed Martin and Virgin Galactic,
as well as separate technology development contracts to other contenders.
/end-quote

It will be interesting to see if the mentioned players can actually meet
those cost targets given their history...

Also curious to see VG given mention. None of the mentioned players have
hardware anywhere close to what SpaceX has. The omission is glaring.
What is DARPA's *real* intent? A viable second source? Since apparently
the qualification for receiving a "study" contract is a good PowerPoint
presentation.

The $5 million figure is also interesting. Why that figure DARPA? I
remember reading SpaceX's goal was $10 million / launch. Which is
already an order of magnitude below where we are today. Wassup DARPA?
$10M not good enough for ya?


Suggest you go look at the real program "requirements" in the
Proposers' Day Announcement posted at FedBizOps.

"David Spain" wrote in message
...
On 9/20/2013 4:41 PM, wrote:
"The U.S. Defense Advanced Research Projects Agency (Darpa) plans to
seek industry interest next month in an Experimental Spaceplane (XS-1)
which will be capable of delivering a payload up to 5,000 lb. to space
for less than $5 million per launch.

What I find most interesting about this article is who is NOT mentioned.
SpaceX and Stratolaunch.

Esp. noticeable is no mention of SpaceX which has already been running
its "Grasshopper" test series. Even though in the article it states:

/quote
The initiative was unveiled at the recent Space 2013 conference in San
Diego by Darpa Tactical Technology Office Deputy Director Pam Melroy.
Although the agency has released artist’s impressions of winged XS-1
concepts, Melroy emphasizes the goal is reusability and the method of
achieving that is up to interested parties. Darpa also believes that
some reusable technology features of the Alasa contenders could also
feature in the larger capacity XS-1. The agency has awarded Alasa
concept study contracts to Boeing, Lockheed Martin and Virgin Galactic,
as well as separate technology development contracts to other contenders.
/end-quote

It will be interesting to see if the mentioned players can actually meet
those cost targets given their history...

Also curious to see VG given mention. None of the mentioned players have
hardware anywhere close to what SpaceX has. The omission is glaring.
What is DARPA's *real* intent? A viable second source? Since apparently
the qualification for receiving a "study" contract is a good PowerPoint
presentation.

The $5 million figure is also interesting. Why that figure DARPA? I
remember reading SpaceX's goal was $10 million / launch. Which is
already an order of magnitude below where we are today. Wassup DARPA?
$10M not good enough for ya?


It's clear that there are some dark political forces at work with the
intent of tripping up SpaceX. As I said many times before the U.S.
Congress is a corrupt bunch of carpetbaggers which are
merely doing the bidding of large conglomerates like Boeing and
LockMart. Everything these conglomerates do costs billions of dollars,
even screwing in a light bulb.

I wouldn't be surprised if Congress pressures NASA into choosing
Orbital's Antares / Cygnus for future COTS missions exclusively, even
though Antares and Cygnus are mostly foreign made. The Antares
has Russian NK-33 engines and Ukrainian fuel tanks. The Cygnus is
basically a derated European ATV built by Thales Alenia Space.

On 9/22/2013 8:12 AM, Robert Clark wrote:
"David Spain" wrote in message
...
...

The $5 million figure is also interesting. Why that figure DARPA? I
remember reading SpaceX's goal was $10 million / launch. Which is already
an order of magnitude below where we are today. Wassup DARPA? $10M not
good enough for ya?

Dave



Do you have a reference for that $10 million number? Elon in a Spacenews
article said he expects to reduce costs by only 25% by a reusable first
stage only:


http://www.spacenews.com/article/lau...on-9%E2%80%99s

No. When I double checked I saw that I was confusing the launch cost
figures for non-reusable Falcon 1 and Falcon 9. Sorry.

http://en.wikipedia.org/wiki/Falcon_...uture_concepts

But I agree with your comments in the comment section of your cited
reference however that a savings of only 25% using a fully-reusable
first stage seems very conservative. Given that Musk already states that
fuel is only ~0.4% of his firm's launch costs.

That figure (0.3% to 0.4%) is quoted in several places but here is one
reference (see para 6):

http://www.popularmechanics.com/scie...-plans-6653023

And in this article we have Musk reported to be saying that the first
stage accounts for 3/4 of the total price tag:

http://www.space.com/21386-spacex-re...kets-cost.html

So if we go at $56M for a Falcon 9, 3/4 is $42 million.
Assuming no re-usability of the upper stage but a fully reusable first
stage then we have a recurring cost (less fuels/ops/etc) of 56-42=$14M.

From this cite:

http://www.zmescience.com/space/spac...eaper-0432423/

I get a rough figure of ~$200,000 for fuel/oxidizer in the first stage
so now an estimated figure ought to be in the range of $14.2 million
assuming a throw-away upper stage. Still a lot better than 25%. In fact,
as you point out Robert in your commentary in your cited link, 25% of
the current price would seem to BE the resulting cost figure not a
reduction thereof.

This cost is for the rocket alone, not counting payload. Also ignoring
infrastructure/operations/overhead/refurbishment costs and any
amortization of the cost to build a reusable first stage. So this is I
think still an optimistic figure you might see only later as the program
matures and also assuming no advancement in reusable upper stage
technology which ought to drive costs even lower.

This is or at least ought to be achievable in the near term (within 10
years) using hardware (Grasshopper) that is undergoing test now. So I
tend to believe this is where we are today at slightly beyond current
state of the art.

DARPA is certainly free to fund research to push beyond what is
currently beyond the edge. But I find it curious no money is going to
the current leader in reusable to-orbit technology. Which makes me think
this is more of a "competitive technology" effort so that the government
is not beholding to one-vendor. Not necessarily a bad thing either. IF
those competitors can deliver. Or maybe SpaceX is just coming late to
the game and will participate in the program with a Dragon atop a
"Falcon 9R+", with the DARPA money to be used to develop a fully
reusable upper stage.

We'll see...

Dave

On 9/22/2013 7:14 AM, me wrote:

Suggest you go look at the real program "requirements" in the
Proposers' Day Announcement posted at FedBizOps.


I downloaded the PDF. At first glance, this seems like a complex way to
go about building a Mach 10 aircraft, if that's what you really want.

I can't help but feel this is the case of the Air Force engaging in a
bit of "Air Forcing". i.e. Gee, we want a Mach 10 aircraft for other
reasons but it's too expensive to budget for it using only DoD money for
an aircraft with limited to no mission requirement. Hmmm. How do we get
others on board? I KNOW, we make it a space launcher! And voila it
obtains immediate legitimacy and pays for itself by providing payload to
LEO!

Yeah, that's the ticket!

Now maybe that's not being fair. But I am sure getting that sense of
"Air Force Space Shuttle" deju vu all over again...

Dave

On 9/22/2013 10:17 AM, Anonymous Remailer (austria) wrote:
It's clear that there are some dark political forces at work with the
intent of tripping up SpaceX.

Not sure that is the motivation here. I'm thinking perhaps DARPA is just
looking at either 2nd sourcing against SpaceX, or maybe looking for a
way to legitimize funding a Mach 10 aircraft, or maybe SpaceX just
simply hasn't applied for any grant money...

2nd sourcing is a phenomena common to commercial industry. It isn't
necessarily indicative of any nefarious schemes.

Dave

On 9/23/2013 9:23 AM, David Spain wrote:.
or maybe SpaceX just
simply hasn't applied for any grant money...


Or simply hasn't expressed any interest in this program, since this so
far appears to be just an unfunded initiative to gauge interest. We know
SpaceX has already "expressed" interest in doing at least some aspects
of this.

There is a slant to the article towards wanting to develop some type of
"space plane" or Mach 10 air vehicle, but it is also stated in the
article that that is not a requirement.

As Robert Clark has already pointed out in commentary after the OP cited
article, there exists an option of putting an X37B on some type of
reusable booster that might also meet the requirements. To be sure I'd
have to check on the cargo capacity of the X37B. The article in the OP
mentions delivery of a payload "up to 5,000 lbs for $5M per launch".

10 launches in 10 days being one of them, according to the downloaded
pdf I read.

A mature Falcon-9R program might be able to achieve that.
I haven't run any numbers to see if an X37B/Falcon-9R is doable so I
can't say.

Also I wonder what is driving the necessity of that 10/10 requirement
from a DARPA perspective?

Dave

http://arc.aiaa.org/doi/abs/10.2514/6.1968-618

http://arc.aiaa.org/doi/abs/10.2514/3.30138

In the 1960s we achieved 5,224 m/sec exhaust speeds with chemical rockets.

Basically, you take nanoparticles of fluorine ice along with nanoparticles of lithium and suspend them in a super-cooled mixture of liquid hydrogen.

F -219.6 C mp 1.505 g/cc 0.55
H2 -252.9 C bp 0.070 g/cc 0.25
Li +180.5 C mp 0.535 g/cc 0.20

Overall density of 0.232 g/cc

To attain the same performance as the Space Shuttle requires a vehicle achieve a delta vee of 9,200 m/sec. A single stage vehicle with a 5,224 m/sec exhaust velocity requires a propellant fraction of;

u = 1 - 1/exp(9200/5224) = 0.82814

Now, consider a Super Light Weight Tank for the Space Shuttle:

SLWT Specifications

Length: 153.8 ft (46.9 m)
Diameter: 27.6 ft (8.4 m)
Empty Weight: 58,500 lb (26,500 kg)
Gross Liftoff Weight: 1,680,000 lb (760,000 kg)

LOX tank

Length: 54.6 ft (16.6 m)
Diameter: 27.6 ft (8.4 m)
Volume (at 22 psig): 19,541.66 cu ft (146,181.8 US gal; 553,358 l)
LOX mass (at 22 psig): 1,387,457 lb (629,340 kg)
Operation Pressu 20-22 psi (140-150 kPa) (gauge)

Intertank

Length: 22.6 ft (6.9 m)
Diameter: 27.6 ft (8.4 m)

LH2 tank

Length: 97.0 ft (29.6 m)
Diameter: 27.6 ft (8.4 m)
Volume (at 29.3 psig): 52,881.61 cu ft (395,581.9 US gal; 1,497,440 l)
LH2 mass (at 29.3 psig): 234,265 lb (106,261 kg)
Operation Pressu 32-34 psi (220-230 kPa) (absolute)
Operation Temperatu -423 °F (-252.8 °C)[9]


It has a LH2 tank with 1,497,440 l capability and a LOX tank with 553,358 l capability. A total of 2,050,798 l. At 232 grams per liter this has a total capacity of 475,785 kg. Dividing this by u we have a Take off Weight of;

TOW = 475,785 / 0.82814 = 574,519 kg.

Subtracting off the propellant and structure we have;

payload = 574,519 - 475,785 - 26,500 = 72,234 kg

Less any additional structure required - e.g. - engine, avionics, etc., plus any savings or removals (intertank, cross-feed, support structure, etc.)

A payload of 72,234 kg in LEO requires only 7,750 m/sec delta vee to go to the moon, land, and return to Earth;

2,950 m/sec LEO to TLI
2,400 m/sec TLI to Lunar Surface
2,400 m/sec Lunar Surface to Trans-Earth Injection

7,750 m/sec TOTAL delta vee.

So, the propellant fraction here is;

u = 1 - 1/exp(7750/5224) = 0.773166

So, with a total weight on orbit of 72,234 kg we have a need for

propellant = 72,234 * 0.773166 = 55,849 kg

at 232 grams per liter we have a volume of 240,729 liters. Only 0.117383 x the size of the External Tank. This means an miniature external tank only

(0.117383)^(1/3) = 0.48963

times the size of the original, will achieve this.

Length: 75.3 ft 23.0 m
Diameter 13.5 ft 4.1 m
Empty: 3,110 kg


So, a payload to the moon and back would be;

payload = 72,234 - 55,849 - 3,110 = 13,275 kg

Now, if we take the propellant mass, and divide it by the propellant fraction needed to attain orbit, we can calculate the payload (if any) this second stage could carry to orbit;

TOW = 55,849 / 0.82814 = 67,439

payload = 67,439 - 55,849 - 3,110 = 8,480 kg

So, we can see that we can build a smaller vehicle capable of putting 8.4 tonnes (18,656 lbs) into LEO and later, a larger vehicle of the same design capable of putting up 72.2 tonnes into LEO, that carries a second stage capable of placing 13.2 tonnes (29,195 lbs) on the moon and returning it to Earth.

The larger SSTO could put up a 1 giga-watt solar power satellite 815 meters in diameter that uses solar powered ion engines for attitude control and to boost from LEO to GEO. The satellite beams 10 MW to 100 ground stations on Earth simultaneously. At $0.11 per kWh the satellite earns $964.26 millions per year. Over a 30 year period the satellite earns $28.9 billions and on the day it begins earning revenue it has a net present value of $12.6 billions. Preselling 100 thirty year energy contracts to 100 buyers in Japan for 10 MW power receivers at a 20% discount over five year construction period obtains $5.1 billions per satellite. Preselling three hundred ground stations for $51 million each obtains sufficient revenues to build the launch system described a fleet of three rockets as well as a supply chain for the launcher and satellite production. Selling five 1 GW satellites per year earns $63 billions per year - more than all the space programs in the world combined. This provides revenue to

(1) send astronauts to the moon and mars, and build up capabilities there
(2) launch a network of satellites to provide a global wireless hotspot
(a) earn revenues from communications,
(b) internet services,
(c) banking and mediation services,
(d) telepresence,
(e) telerobotics
(3) use additional revenues to expand launcher system and powersatellite size