Mach 10 X43A Flight Successful

Sector Bug writes "NASA's X43A research aircraft made its third and final flight today, firing its scramjet engine at Mach 10 (7,000 MPH) or close to it, setting a new record. "

Comments

Speed comparison question

[Drakonian]

A (possibly stupid) question: How does this compare to the speed of orbital rockets?

Re:Speed comparison question

[Fnkmaster]

While that is true, this is the first real scramjet implementation. Apparently, people think scramjets will go up to about Mach 15, or over 10,000 miles per hour. While still not low earth orbital velocity, it doesn't have to get there to be useful in getting to orbit.

If a traditional rocket kicks in at Mach 15 to get the rest of the way to orbit, the savings in launch weight and thus cost from not having to carry all that oxidizer to get up to Mach 15 could still be quite large.

Re:Speed comparison question

[frugle]

To allow particle accelerators you need to expand your parameters a bit to include natural objects accelerated by man.

The fastest "man-made" objects - I would hazard a guess at probes sent from Earth to other planets. Voyager 1 travels at roughly 17.4 km/sec or 38,923 MPH

This will all be put to shame by the Mini-Magnetospheric Plasma Propulsion system (M2P2) - which if it actually got into production and was launched could overtake Voyager1 (launched in 1977 with a 11 Billion Km head start) in 10 years.

This M2P2 drive in a nutshell would create a 60 km wide magnetic field filled with plasma behind it, trapping the solar wind and propelling it to a predicted 180,000 mph.

Let's just hope with all that trapped wind they have enough gaviscon to stop it when it gets where it's going...

Re:Speed comparison question

[Total_Wimp]

If a traditional rocket kicks in at Mach 15 to get the rest of the way to orbit, the savings in launch weight and thus cost from not having to carry all that oxidizer to get up to Mach 15 could still be quite large.

I've heard the idea of using three stages in scramjet orbital launches. The first and third are rockets and the middle is the scramjet. It makes me kind of curious about using chemical propellants, like in a giant howitzer, to propell the scramjet to it's initial speed.

I couldn't see this doing much for manned flight, but most of what we send up isn't manned anyway. It could also have some pretty kick ass millitary application, say for dramatically increasing the payload of current rocket propelled artillery rounds.

TW

Re:Speed comparison question

[Rei]

IAMAAE, but the reason that they're more economical is that you only need to carry up ~1/9 of your propellant mass during the airbreathing stage. For example, a LH/LOX rocket uses 2 H2 + 1 O2 -> 2 H2O; For molecular weights, H2~=2, O2~=32; thus, the ratio is (32+4)/4 -> 9 times as much mass for the LH/LOX rocket.

More importantly, however, is the fact that the more mass your craft has, the more energy it takes to accelerate that mass; consequently, craft masses grow geometrically with a given desired increase in delta-V. The net benefit from only needing to carry up your fuel is staggering. Even if you use a hydrocarbon fuel (much denser, which is a very good thing, plus often not cryogenic), you're still going to get at least a 6-fold instantaneous mass difference (which, again, becomes more dramatic as you factor in how much it saves you from having to accelerate propellant).

Also, they're theoretically simpler, lower maintainance, and less likely to fail because of the reduced number of moving parts. They're just in general Good Things(tm). :)

Also last flight of the B-52B mother ship ...

[xmas2003]

The B-52B (tenth off the assembly line) first flew on June 11th, 1955 and among other things, has carried the X-15, Shuttle solid rocket booster, and finally the X-43A (on the same pylon as used by the X-15). Read more about the ol' BUFF at NASA.