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There is some speculation that the AR2-3 may not be the engine used in current flights (see other replies to you post).

However, the AR2-3 is human rated. The X-37 is nominally unmanned, but hey the missions are classified, and because Halo Orbital Drop Shock Troopers. Of course some of the alternative engines you mentioned have been used on stages of previous manned flights and are thus presumably man-rated as well.

I did some Binging on the AR2-3 and found a NASA/Rocketdyne/OSC presentation that looks to be drafted around 2000.

Here that seem to make the case high test peroxide (HTP) technologies are the way of the future for upper stage propulsion:

Hydrogen peroxide was selected over liquid oxygen because it is dense, storable, capable of tolerating months in orbit, and meets safety restrictions for being part of the payload in the Space Shuttle.

Of course the Shuttle aspect is no longer a factor, but the other factors still seem to be in play.

Further into the paper, the USFE 10k peroxide motor is mentioned as a project to develop new HTP technologies. These technologies would be used for future HTP-based upper stages. They even have a goal of over 100 uses of an engine before it has to be removed for overhaul. Is that a lot in the world of rockets? As this paper was drafted around 2000 I would guess that the X-37 is using something a bit different that the bog-standard AR2-3 or has moved away from HTP technologies altogether.

Now to say that rocket science has moved away from HTP is not quite true. I don't think there are any big HTP engines used in lower stages. However, the Bloodhound SSC is using a HTP hybrid motor they are designing.

There is also research in to using HTP as a monopropellant for thrusters using a catalytic bed. I suppose the advantage here is that you have HTP as your oxidizer for an upper stage and then it can be used for maneuvering once on orbit. Similar, as you mentioned, to UDMH.

Take a look at the Introduction from the ESA paper referenced above. They cite several reasons why HTP is desirable and advantageous. Cost and safety being paramount. They also mention that Soyuz has been using HTP in its maneuvering systems for over 40 years. I think that HTP safety concerns have been effectively mitigated from the "explode because you looked at it funny" era.

As for performance it seems that HTP is as good as some other technologies, but it's no dog either and it seems to be a good fit for the X-37 or other small stages. Quote from the ESA paper:

The propulsive performance of hydrogen peroxide monopropellant rockets is about 20% lower than hydrazine, but the volume specific impulse achievable with 90% H2O2 is higher than most other propellants due to its high density. This is particularly useful for systems with significant aerodynamic drag losses and/or stringent volume constraints. With respect to bi-propellant and hybrid rocket engines, hydrogen peroxide yields a specific impulse comparable to other liquid oxidizers like dinitrogen tetroxide, nitric acid and even liquid oxygen..

It seems that HTP has many uses and rocket science has not moved away from HTP, indeed, it is being actively researched. It may or may not be used on the X-37 right now. It may or may be used on the X-37 in the future. With further attention to cost, safety, and, increasingly, environmental impact, HTP seems to be coming for you...

Ouch... really???

Of course it can't turn at full speed in just 240m. 240m is the distance across the circle (diameter) for the vehicle to "Turn Around" (turning radius 120m.)

In light of this impressive record, surely BLOODHOUND will return to the Black Rock Desert? Sadly, no. A lack of rain over the last decade, together with increasingly heavy use for the playa surface (principly by the annual Burning Man festival) has left the Black Rock surface in poor condition. It is bumpy, crumbly, rutted and uneven for much of its 140+ square mile surface and is not currently a suitable surface on which to run a car like BLOODHOUND. Hence an alternative surface is required – and we need to find one, wherever in the world it may be.

Take a look at the speedometer:
http://www.bloodhoundssc.com/s...

It is graduated from 1 to 11. At the bottom is the subscript "MPH x 100". I'm used more to "RPM x 100"! Oh, and instead of an outstanding graduation at 55 MPH, it has an outstanding graduation at Mach 1!

Slight correction - it's a 2.4L engine...to run the fuel pump.

They are aware of this. See the footnote to the poster on this page.

"How about automated steering, or some kind of ‘fly-by-wire’ computer stabilisation? No – the rules do not allow it, and quite right too in my opinion. In order to be a land vehicle in LSR terms, the FIA rules require that the vehicle is ‘wholly and continuously controlled by the driver’. Even if the rules did allow for a computer system, should we really be running a car that needs a computer (which will be untested in this prototype vehicle) to keep it safe?"

Kind of crazy that a team developing an open-source supersonic car is afraid of using computer control assistance methods that have been around for decades!

At least on land; a 1000mph car, the Bloodhound SSC FTW!

Bloodhound Supersonic Car http://www.bloodhoundssc.com/education.cfm development includes educational materials. Plenty of real world problems to be solved.

Actually, it doesn't even have tires*, the wheels have to be machined from solid titanium in order to withstand 50,000g ( http://www.bloodhoundssc.com/car/wheels.cfm for details).

* going for a 1 point pedantry bonus: it's British, so the things it doesn't have are tyres.

So the job of the 800 break horse power internal combustion engine is to deliver fuel into the rocket engine (not the jet engine). But the rocket is a solid fuel booster (essentially a glorified fireworks motor). Err wait, what? What do you need a fuel pump for a solid fuel rocket booster?

It's not a pure solid fuel rocket. It contains solid fuel, but then they pump hydrogen peroxide thru the rocket as an oxidizer. That's being pumped by the F1 engine. Seeing how it has to pump one ton of HTP in 22 seconds, you can see why they need that much power for the pump. More details on the rocket engine.

So the job of the 800 break horse power internal combustion engine is to deliver fuel into the rocket engine (not the jet engine). But the rocket is a solid fuel booster (essentially a glorified fireworks motor). Err wait, what? What do you need a fuel pump for a solid fuel rocket booster?

It's not a pure solid fuel rocket. It contains solid fuel, but then they pump hydrogen peroxide thru the rocket as an oxidizer. That's being pumped by the F1 engine. Seeing how it has to pump one ton of HTP in 22 seconds, you can see why they need that much power for the pump. More details on the rocket engine.

I know someone who is involved in the Bloodhound project, working with a large education company over here (one of the sponsors of the car). There is a really big focus on the education side of things with this; they're touring schools and colleges doing presentations, along with a full size replica of the car. One of the big reasons for doing it is to get kids at school interested in science, maths and engineering and that seems like a pretty good idea because there has been a continuing decline in students going on to study those subjects at higher levels in the UK (and I believe most Western countries these days).

There's a bit about it on their website http://www.bloodhoundssc.com/education.cfm . I also doubt that the overall resource usage for the entire project is actually that high (I'd bet fewer resources used than most Hollywood films for instance), so if it increases interest in the areas they're targeting so that general science and engineering gets a bit more attention, I don't think that's too bad a result.

.

Yes.

Because records are always increased with time, because it can be done.

Bloodhound SSC is a project designed to showcase British engineering capabilities and talent and to enthuse and encourage the next generations of engineers who are currently at school and have not yet decided what they want to do for a career.

Have a look at the project web site, all the information is there.

http://www.bloodhoundssc.com/

Again not street legal http://www.bloodhoundssc.com/

Note that unlike Formula 1 and other car racing, land speed racing is very open about technology--sounds like they will be "open sourcing" most of the engineering as part of the educational focus.

Note that unlike Formula 1 and other car racing, land speed racing is very open about technology--sounds like they will be "open sourcing" most of the engineering as part of the educational focus.

Note that unlike Formula 1 and other car racing, land speed racing is very open about technology--sounds like they will be "open sourcing" most of the engineering as part of the educational focus.

It will be in a desert obviously as they discuss Here. Breaking and setting most top speed records of this calibre have been attempted at the Bonneville Salt Flats, Utah, USA so my bet would be there however I don't believe they have figured out exactly where they want to do it yet.