A Kerosene-Fueled X-33 as a Single Stage to Orbit Vehicle.

[EarthlingX]

This looks like a fuel line, for orbital fuel depots. Tanks could be used as a building material instead of burning though.

 

[exoscientist]

Nice list of launch vehicle designs, including some SSTO's going back to the 60's:

Space Future - Vehicle Designs.
http://www.spacefuture.com/vehicles/designs.shtml

Here's a review of SSTO concepts proposed over the years:

History of the Phoenix VTOL SSTO and Recent Developments in Single-Stage Launch Systems.
Gary C Hudson
http://www.spacefuture.com/archive/hist ... tems.shtml

And this article argues that SSTO performance has long been possible for expendables, and that a reusable one is possible with modern materials:

Launch Vehicle Design.
"Contrary to what many people who make expendable rockets will tell you, it isn't difficult to design a "single stage to orbit" ( SSTO) rocket. In fact it's very easy - it can be done with rocket engines and propellant tanks designed, manufactured and operated 20 years ago! It's important to know this, because a lot of people will try to tell you otherwise.
"A Thought Experiment
"This very idea was written up by Gary Hudson in "A Single-Stage-to-Orbit thought experiment".
"If you attach 6 SSMEs (Space Shuttle Main Engines) directly to a Space Shuttle External Tank ( ET), you could launch 30 tons payload to orbit. It wouldn't be an economical way to launch - but it's certainly possible. But please note: it's only possible taking off vertically; no-one can build a horizontal take-off SSTO.
"But, of course, if you carry passengers to orbit you'll want to bring them back - and that's what's tricky: to build a fully reusable SSTO, not an expendable, one-way ride. "
http://www.spacefuture.com/vehicles/building.shtml

As this article notes, many people don't think a SSTO vehicle is possible even with expendables. That is why with the rapid drop in the cost of composite materials I'm arguing that small test vehicles of all-composite construction should be built to prove the principle of SSTO at least for expendables. This would be possible and affordable to do even for the smallest of the New Space companies with in house construction of the composite materials.
Then when it is seen that SSTO, though not reusable, performance is possible for an actual working rocket, it will be more believable that following well-known scaling principles that larger rockets should allow reusable versions with significant payloads.


Bob Clark

 

[EarthlingX]

Currently there is a fully RP-1 fueled first stage of a HLV under consideration:
NASA weighs Ares alternatives, including an heir to the Saturn V

Related discussion on the nasaspaceflight.com :
All liquid HLLV replacement for Ares being looked at "seriously"

Some more all liquid options:
All-Liquid: A Super Heavy Lift Alternative?

 

[vulture4]

The heavy version of the Delta is already operational and is all-liquid. Notional growth versions all the way up to 100-tons to LEO were proposed by Boeing early in the Delta IV program; some used small SRBs but the largest version was again all-liquid. An all-liquid Atlas V heavy was also proposed. Of course these were all two-stage vehicles, and the Delta does not use kerosine, but the Delta IV first stage alone could surely make it into orbit if the thrust could be throttled back sufficiently; the burn time would have to be prolonged past the normal four minutes.

 

[EarthlingX]

Here's a paper from 1996, discussing how to make a rocket engine reusable.
Rocket engine life analysis:
http://science.ksc.nasa.gov/shuttle/nex ... e_Life.pdf

I guess a lot of this has been done.

 

[exoscientist]

Thanks for those links, Earthling, on the proposed kerosene rockets. The question of using Russian engines might be eliminated if NASA restarted development of the RS-84. It has comparable performance of the Russian RD-180, plus it is reusable.
If NASA hadn't cancelled the RS-84 in 2004 it would have been ready for prototype testing by 2007:

One step closer to next-generation spaceflight: RS-84 engine passes preliminary design milestone.
For release: 07/15/03
"The design team's next major program milestone is the "40k" preburner test, a series of test-firings of a nearly full-scale preburner yielding 40,000 pounds of thrust. The test series, which will be conducted at NASA's Stennis Space Center in Bay St. Louis, Miss., is scheduled to be completed in September. The final RS-84 prototype is expected to begin full-scale test firing by the end of 2007."
http://www.nasa.gov/centers/marshall/ne ... 3-119.html

We likely would have had an operational 1,000,000 lb. thrust engine before the planned end of shuttle flights in 2010.
Since the RS-84 was canceled 3 years before the expected start of its prototype testing, it might conceivably take only an additional 3 years from now, so to 2012, if we restarted development this year to have a prototype ready.


Bob Clark

 

[EarthlingX]

Yea, that was mine line of thought too. Plus SpaceX is already working on them, as docm reported. It might be done COTS way. I expect those Rocketdyne findings have found a way in the design of that engine too, not only RS-68 and i guess j-2x, that's why i thought it related.
I'm not sure, if i'm capable of decent recalculation, what would happen, if a structure material would be replaced with carbon, removed upper stage engines and so on.
There is still a question of heat protection for reentry, but there are a couple of options that don't include heavy thermal protection.

(couldn't resist it)
Delta IV launch:

 

[neutrino78x]

This would have just below suborbital to suborbital performance, but the price would be significantly less than the DC-Y full orbital version of $5 billion:

DC-Y.
http://astronautix.com/lvs/dcy.htm

Doesn't vertical landing necessarily use more fuel than landing aerodynamically, like the Space Shuttle? I would want a craft that takes off and lands like an airplane, ideally.

--Brian

 

[EarthlingX]

This would have just below suborbital to suborbital performance, but the price would be significantly less than the DC-Y full orbital version of $5 billion:

DC-Y.
http://astronautix.com/lvs/dcy.htm

Doesn't vertical landing necessarily use more fuel than landing aerodynamically, like the Space Shuttle? I would want a craft that takes off and lands like an airplane, ideally.

--Brian

Not necessarily. First you start your powered braking above the atmosphere, loose most of the speed before getting into thicker layers, where aero-braking gets hot. This is how you reduce need for a thermal protection, which can make a big part of mass of a lander.
You can then deploy parachutes, and finish with powered landing, like Soyuzes, maybe a little higher

This scenario of course assumes orbital fuel depots, where you get fuel for the braking.

 

[exoscientist]

Video of SpaceShipTwo assembly, showing the all-composite construction, including the structural members:

[youtube]http://www.youtube.com/watch?v=B8XaJbwwT68[/youtube]


Bob Clark

 

[EarthlingX]

Wow, i was watching some time, before i realized, those people are moving the hull, that's what usualy cranes do .. :shock:

 

[MeteorWayne]

Video of SpaceShipTwo assembly, showing the all-composite construction, including the structural members:


Bob Clark

Bob, please post SS2 realted material in the SS2 thread

Wayne

 

[exoscientist]

The reason for posting it here was that I meant to show, by the handling of the technicians, how light a fully composite spacecraft could be. At the beginning they are also moving around the engine which also looks to be composite.
The overwhelmingly key question about the possibility of a reusable SSTO is whether or not it could be made light enough. I'm arguing it can be if made of all composite construction. This video gives further support of that argument.

Bob Clark

 

[MeteorWayne]

OK, I didn't remove it from here. It is related to the subject.

 

[exoscientist]

The Air Force is researching reusable hydrocarbon-fueled first stage
boosters to be used with expendable upper stages to cut the costs to
space by 50%:

USAF Seeks Reusable Booster Ideas.
May 14, 2009
By Graham Warwick
"AFRL's reference concept includes an integral all-composite airframe
and tank structure that carries both internal pressure and external
flight loads. The concept vehicle is powered by pump-fed liquid-oxygen/
hydrocarbon rocket engines."
http://www.google.com/url?sa=D&q=http:/ ... yOHIY-kKiw

This article discusses wind tunnel tests of a scale-model of such a
booster:

AEDC team conducts first test on a reusable space plane.
Posted 12/16/2009 Updated 12/16/2009

http://www.arnold.af.mil/news/story.asp?id=123182588

It is interesting they are proposing an all-composite construction
including propellant tanks for this reusable hydrocarbon-fueled first
stage booster.
As I have argued, an all-composite, hydrocarbon-fueled design would
allow even a reusable single-stage-to-orbit vehicle.


Bob Clark

 

[EarthlingX]

Here is one more point for a composite structure:
Advanced Composite Mate Joint Passes Stringent NASA Tests For Crew Module

An innovative method for joining composite structures implemented by Northrop Grumman has passed a series of intensive structural tests, paving the way for the use of composites in future spacecraft.

 

[exoscientist]

A report arguing in favor of kerosene fuel with H2O2 oxidizer for
the propellant of a SSTO:

A Single Stage to Orbit Rocket with Non-Cryogenic Propellants.
Abstract
"Different propellant combinations for single-stage-to-orbit-rocket
applications were compared to oxygen/hydrogen, including nitrogen
tetroxide/hydrazine, oxygen/methane, oxygen/propane, oxygen/RP-1,
solid core nuclear/hydrogen, and hydrogen peroxide/JP-5. Results show
that hydrogen peroxide and JP-5, which have a specific impulse of 328
s in vacuum and a density of 1,330 kg/cu m. This high-density jet fuel
offers 1.79 times the payload specific energy of oxygen and hydrogen.
By catalytically decomposing the hydrogen peroxide to steam and oxygen
before injection into the thrust chamber, the JP-5 can be injected as
a liquid into a high-temperature gas flow. This would yield superior
combustion stability and permit easy throttling of the engine by
adjusting the amount of JP-5 in the mixture. It is concluded that
development of modern hydrogen peroxide/JP-5 engines, combined with
modern structural technology, could lead to a simple, robust, and
versatile single-stage-to-orbit capability."
http://www.erps.org/docs/SSTORwNCP.pdf [full text]


Bob Clark

 

[Jazman1985]

The design in this paper reminds me an awful lot of Blue Origin. Same overall size, shape, and uses one of their known fuels(H2O2).

 

[Astro_Robert]

Please keep in mind as someone mentioned at the top of the thread that X-33 was only a technology demonstrator granted experimental status and meant only to advance certain key technologies to a higher Technology Readiness Level (TRL) to provide risk reduction for the VentureStar follow on vehicle.
Some of the key development technologies were:

Hull Shape: A hypersonic lifting body with a triangular planform was a new thing. Note that DC-C type craft would have needed to carry propellant for landing, and Shuttle type vehicles have drawbacks concerning cross range.
Engines: Nobody has ever flown an Aerospike engine before, although it was thought that the engine would be synergistic with the hull form. The LASRE program did obtain some data, and several full power engine runs were conducted at Stennis, in flight configuration.
Composite Fuel Tank: Probably the #1 discriminator was to make the much maligned Hydrogen Tank(s) out of composites to lighten structural tank weight fraction. In fact the actual tanks were lighter, stiffer, and suffered less thermal expansion than metal tanks used by launch vehicles today. It is unfortunate that the tank failed in post test warm-up. Also note that the much ballyhood DC-X used a tank liner for its tanks.
Thermal Protection System: X-33 employed advanced and robust thermal protection system that combined skin structural elements with the TPS role. Again, for a given surface area, this system was tougher and comparable or less weight than Shuttle systems in use. Samples of this system were flown on special test panels by jet aircraft.

As far as including multiple tanks of various sizes to increase fuel fraction, too many tanks = too much plumbing. Too much plumbing = cost, weight, and technical risk.

Again X-33 was a tech demo only, the VentureStar would not have been merely a scale model, but would have incorporated other advances and lessons learned. Many very smart people in government and industry studied this problem for several years, and if they came close but suffered an unfortunate failure for a risk averse NASA, then we can all be saddened that such a vehicle has never flown.

Part of me just finds it a little bit humorous when laypeople with apparently little expertise or knowledge of things self proclaim as to whout should have been or could be possible.

 

[EarthlingX]

Please keep in mind as someone mentioned at the top of the thread that X-33 was only a technology demonstrator granted experimental status and meant only to advance certain key technologies to a higher Technology Readiness Level (TRL) to provide risk reduction for the VentureStar follow on vehicle.

It was also very inspiring, cost measly 1.3 G$, comparing to stick, and quoting wikipedia:

Thus, the X-33 was not only about honing space flight technologies, but also about successfully demonstrating the technology required to make a commercial reusable launch vehicle possible.

http://en.wikipedia.org/wiki/X-33

Part of me just finds it a little bit humorous when laypeople with apparently little expertise or knowledge of things self proclaim as to whout should have been or could be possible.

We do what we can with information we have available. Show us more, we'll know more and you are more than welcome to show faults in our reasoning, that's the point, right ?

 

[exoscientist]

Please keep in mind as someone mentioned at the top of the thread that X-33 was only a technology demonstrator granted experimental status and meant only to advance certain key technologies to a higher Technology Readiness Level (TRL) to provide risk reduction for the VentureStar follow on vehicle.
...

The X-33 was used as an example for what is possible IF instead of focusing on hydrogen as the fuel for a SSTO we used dense propellants. Kerosene is just the most commonly used one. It probably is not the most ideal dense propellant to use for the purpose.
The X-33's design makes it a little more difficult to come up with the solutions to bring it to operational status. But the overwhelming key point I want to make is that by using an all-composite structure with dense propellants, standard cylindrical rockets can be made into SSTO's because dense propellants allow such high mass ratios, as proven by actual rockets in use for decades, that by using all-composite design the weight savings can go to payload, landing gear and thermal protection.


Bob Clark

 

[Astro_Robert]

As far as dense fuels, you or someone else mentioned much earlier in the thread that the tankage for Kerosene would be bulkier than for Liquid Hydrogen (LH2). In an SSTO this is probably a severe penalty. The principal advantage of using Kerosene over LH2 is that cryogenic handling is not required, simplifying the fuel loading, and possibly even thermal protection. A few staged launch vehicles have employed this historically, and even today.

Your SSTO has 2 most likely mission types, either to enter into a stable orbit or parking orbit and release its cargo/payload, or operate as a re-usable first stage and release its cargo while itself only achieving suborbital. In the first case, each pound of structure = 1 less pound of payload. In the latter it is not quite as bad but still each pound of additional structure does hurt. Energetically, the weight penalty of the larger Kerosene tankage likely outweighs the benefit from not using cryogenics for an SSTO. For staged vehicles, Kerosene seems to work fine in practice.

In general it would be very advantageous for us to have more assured, reliable and less expensive access to Earth Orbit. This can take many shapes, SSTO is just one of them. Space Elevators, Bolos, and other technologies have also been proposed many of which may be beyond our current technology, but are not as far-fetched as one might think. In fact, NASA has been holding competition to demonstrate space elevator technologies, and invests in hypersonic propulsion research which could be used to support a Bolo-type of technology.

 

[Astro_Robert]

As far as all-composites, in practice one would have to balance any weight savings with fabrication cost and lifetime. Composites are usually more expensive to fabricate and are often more fragile and can be difficult or impossible to repair. One can use composites as ‘black-metal’ taking composites sections and bolting them together as one would a metal piece. However a lot of the weight is in the joint fasteners so that solves little. If one attempts to make a large bonded structure so save weight, one encounters massive fabrication and quality control issues, again going to cost.

An all-composite vehicle would likely cost much more to fabricate, increasing the costs to be amortized over its lifetime. Chances are that the cost penalty far outweighs the weight savings for an expendable vehicle to be made entirely of composites. The weight penalty of not staging probably requires low cost requiring fabrication and thus would tend to eliminate an all-composite disposable rocket. If the lifetime is not sufficiently long, then the lifecycle costs of operating a re-usable SSTO could actually be greater than that of a staged expendable.

There are 2 primary considerations driving people to consider SSTO vehicles such as X-33: Cost and Responsiveness. One would imagine that not throwing away a $100M rocket every time would save money, but can a $5B vehicle really fly well over 50 times (depreciation vs inflation), the Shuttles have only flown like 30 times each and are falling far short of their claim in that regards. On the Responsiveness side, it is expected that a re-usable vehicle would have better responsiveness but again Shuttle flies only a few times per year per vehicle, and it is the composite TPS that has been one of the drivers in this regard.

X-33 was not all-composite. It actually used metallic primary Thermal Protection System (TPS), and it weighed comparable to or less than the shuttle composite TPS. This is because the shuttle possesses a primary Aluminum skin plus pads plus ceramic bricks, whereas the X-33 only utilized the metallic shield. Being metallic, this shield was tougher than Shuttle tile, and likely would have required much less maintenance. The reason X-33 could use it instead of Shuttle tile, was that as a Hypersonic glider, its re-entry angle was not as steep and hot as shuttle. This slightly more benign environment allowed the use of this newer material.

Again, there are problems with composites that have to be considered, when one contemplates their advantages. Yes they tend to be lightweight, but can be difficult to produce and are not usually as damage tolerant as metal. They tend to have very low co-efficient of thermal expansion which tends to be good in a space vehicle, but necessary metallic pieces may not be compatible with their much different thermal properties.

 

[EarthlingX]

As far as all-composites, in practice one would have to balance any weight savings with fabrication cost and lifetime. Composites are usually more expensive to fabricate and are often more fragile and can be difficult or impossible to repair. One can use composites as ‘black-metal’ taking composites sections and bolting them together as one would a metal piece. However a lot of the weight is in the joint fasteners so that solves little. If one attempts to make a large bonded structure so save weight, one encounters massive fabrication and quality control issues, again going to cost.

Cost issues have been addressed in this thread, and it seams prices went down a lot. There are new ways to bind structure together, as you can also read about in this thread.

An all-composite vehicle would likely cost much more to fabricate, increasing the costs to be amortized over its lifetime. Chances are that the cost penalty far outweighs the weight savings for an expendable vehicle to be made entirely of composites. The weight penalty of not staging probably requires low cost requiring fabrication and thus would tend to eliminate an all-composite disposable rocket. If the lifetime is not sufficiently long, then the lifecycle costs of operating a re-usable SSTO could actually be greater than that of a staged expendable.

If the cost for carbon structure is too high, if it doesn't fly enough, then maybe lifecycle costs could probably be greater ...

There are 2 primary considerations driving people to consider SSTO vehicles such as X-33: Cost and Responsiveness. One would imagine that not throwing away a $100M rocket every time would save money, but can a $5B vehicle really fly well over 50 times (depreciation vs inflation), the Shuttles have only flown like 30 times each and are falling far short of their claim in that regards. On the Responsiveness side, it is expected that a re-usable vehicle would have better responsiveness but again Shuttle flies only a few times per year per vehicle, and it is the composite TPS that has been one of the drivers in this regard.

Which launcher you had in mind for 100 M$ ? Can't remember any such cheap thing in 10t to LEO class ? Where did you get 5 $B ?

X-33 was not all-composite. It actually used metallic primary Thermal Protection System (TPS), and it weighed comparable to or less than the shuttle composite TPS. This is because the shuttle possesses a primary Aluminum skin plus pads plus ceramic bricks, whereas the X-33 only utilized the metallic shield. Being metallic, this shield was tougher than Shuttle tile, and likely would have required much less maintenance. The reason X-33 could use it instead of Shuttle tile, was that as a Hypersonic glider, its re-entry angle was not as steep and hot as shuttle. This slightly more benign environment allowed the use of this newer material.

If it did a bit more braking above atmosphere, had lower entry speeds, it would require even less thermal protection or had less severe requirements for it.

Again, there are problems with composites that have to be considered, when one contemplates their advantages. Yes they tend to be lightweight, but can be difficult to produce and are not usually as damage tolerant as metal. They tend to have very low co-efficient of thermal expansion which tends to be good in a space vehicle, but necessary metallic pieces may not be compatible with their much different thermal properties.

It seams to me, that a lot of that is being addressed, otherwise airlines and car companies would not start introducing this materials in their production lines.

 

[vulture4]

Metallic structural design is quite mature, after over 2000 years of use of metals. Although composites of one type or another have been used in aircraft since the Wright "A" Flyer, the technology of graphite and similar structural materials is new and rapidly evolving. Increased NASA investment in basic composite design technology could benefit everything from future reusable spacecraft to commercial airliners, in fact it might have helped Boeing out quite a bit with the 787. As to the toughness of composites, after the Columbia loss researchers at Ames developed a resilient form of reinforced carbon-graphite but the project seems to have been dropped. Future spacecraft will always use metals as well as composites, but In general composite materials can be extremely tough when that is a design goal.