With such high speeds, the world will get even smaller when long distances will be covered in a fraction of the time it used to take.

You will never find me in one of these things to travel if they can't find a way to circumvent lateral G force. You'd be 10 years stupider by just riding in it.

..then how could it be using atmospheric hydrogen as a propellant? Someone is wrong somewhere.

Lets assume that in 50 years this has been turned into another common, patented, "everyday" technology (like jet engines today). To even get clearance to fly in a scramjet equipped plane would probably require significantly longer security screening... to offset any time saved by traveling around the world in 80 minutes :P

The rocket reached top speed on the way back down to Earth which means it had air for the return trip.

Wiki it dude,
http://en.wikipedia.org/wiki/Earth's_atmosphere
most of the atmosphere lies below 100km - the "atmosphere / space boundary line" but it's still a continuous function of decreasing density - eg; there's still plenty of gas above that - enough for the auroras, and plenty to run a scramjet (http://en.wikipedia.org/wiki/Scramjet) off of.

Wow ..higher than even the Shuttle flies? NOT! Someone better recheck their facts and figures.

I don't think the bombs they'll be putting on them care about those G'z

100km is considered the edge of space. Where in the article did I say that it flew higher than the Space Shuttle?

Some clarifications from someone who knows:
This program has been running for some time, this is not the first flight for the scramjet engine. It is the fastest so far though.
@frick. you'd need to accelerate for about 10min at 0.5g. to hit 3km/s, not a problem.
@irt3, atmmospheric air, carried hydrogen. combine to create a bang = thrust. irt#3 is right. atmosphere goes beyond 100km. Earth observation sattelites experience atmospheric drag. at low altitudes (below say 25km) the air is to thick, and the friction would create temperatures to hot to handle (sr71 blackbird, mach 3 plane flew (flies?) at 25 km)
@ irt7, geostaionary orbit (telecom sats) is 36.000km... Think galactic distances. (moon is 150000km away, sun 150000000km There's space enough)

Weapon.

"The engine was boosted 330 miles into the air".

The ISS orbits at an altitude of about 200 miles. Presumable the 330 miles reference was to downrange distance traveled by the scramjet, not to altitude achieved.

@Nic - Most people won't have that problem since they're already idiots.

@Nick - Lockheed's already got their next gen antitank weapon that fires basically a huge bullet at Mach 2 using magnets. ;)

http://www.newscientisttech.com/article/dn12075

It was a sub-orbital flight. Things like ICBMs and SpaceShipOne are suborbital. They go up, out of the atmosphere, then fall back down.

If they pop up over 60 miles (100km) they are ruled has having entered space. At that height there is effectively no atmosphere. Air slowly gets thicker as you go down. Exotic planes like SR-71s and U2's can fly at around 20 miles. Thunderstorm clouds top out at around 8-9 miles. Airliners typically cruise between 5-8 miles. Mt. Everest is about 6 miles, and it's climbers usually need to carry oxygen supplies for physical activities.

And I type too much. :)

Spacedaily confirms the vehicle was launched to 530km altitude. It achieved the necessary velocity to ignite the scramjet by dropping into the atmosphere. Remember - there's a big difference between going straight up to Shuttle-orbit altitudes and accelerating to 15,000mph laterally to achieve orbit.

I believe that if commercial jet (RAM/SCRAM or whatever hypersonic engine) will get in service, it will no fly a straight line like todays jets. It will climb to above 100km altitude then fall ballisticaly, when it falls under specific hight it will ignite the engine and climb back to top altitude, doing tis all the way. It would be fast as hell and cost effective.

This testing is however clearly so far unstoppable death bringer (military use).

Light speed is too slow! We're going to have to go right to... ludicrous speed!

Whatsa matter colonel sandurrz? Chicken?

The scramjet has been designed for decades...and it's always the same problems. It has a *very* thin operational speed window and must be moving before activation. It simply has not proven practical for common vehicular usage.

"A scramjet requires supersonic airflow through the engine, thus, similar to a ramjet, scramjets have a minimum functional speed. This speed is uncertain due to the low number of working scramjets, relative youth of the field, and the largely classified nature of research using complete scramjet engines. However, it is likely to be at least Mach 5 for a pure scramjet, with higher Mach numbers 7-9 more likely. Thus scramjets require acceleration to hypersonic speed via other means."

http://en.wikipedia.org/wiki/Scramjet

Scramjets were the theroetical rage in the late 70's and early 80's...and died there (I well remember the death of the attempts)

"In the United States, from 1986-1993, a reasonably serious attempt to develop a single stage to orbit reusable spaceplane using scramjet engines was made, but the Rockwell X-30 (NASP) program failed."

SPACEBALL ONE'S GONE PLAID!!

...A vehicle launched into / from space that reaches Mach 10 on the way down is not to transport passengers - it's to be used as a kinetic kill vehicle. At that speed, you don't have to have complex explosives on board - force = M*A. If this thing hit your neighbor's house, you wouldn't have time to scream.

>...A vehicle launched into / from space that
>reaches Mach 10 on the way down is not to
>transport passengers - it's to be used as a
>kinetic kill vehicle. At that speed, you don't
>have to have complex explosives on board - force
>= M*A. If this thing hit your neighbor's house,
>you wouldn't have time to scream.

Wow, that's some bad physics.

You're right about how to calculate force, but it has nothing to do with this story. The speed of the vehicle (this "Mach 10" business) is irrelevant -- 'a' is acceleration, not speed.

Something merely dropped from space, especially something with a substantial amount of mass, would be pretty destructive. For that we can thank nature's acceleration, gravity.

Assuming anyone wanted to build such a pointless device as you mention (every bad science ficton writer has followed the good ones in suggesting it), adding a method of propulsion on the way down would be a waste of time.

Actually, speed plays a huge roll in the destructive nature of an object. We're just using the wrong equations and concepts. For the object with substantial mass, we can find its kinetic energy with its mass and velocity. Last I heard, energy is conserved so the transfer of energy upon impact would be devestating, but I think we digress. The advancements in technology have always presented negative possibilites. I'm one for change and am excited about the positive contributions this technology will bring. Lets just hope we don't all blow each other up before we can use this thing. I'd love to go to NewYork for a weekend.

F=ma works fine. The force on impact (if you really wanted to make such a sophisticated bomb) will be equal to the accelation (negative) req'd to slow the mass down from mach 10 to zero in the space of a few meters.

I just can't imagine anyone being able to survive a plane crash flying at those speeds.

I'd rather travel in a slower plane....and live longer...

...yeah. Because people survive plane crashes all the time. Because the difference between 100s of mph and 1000s of mph matters when you are a sack of meat.

Nice spaceballs reference... =)

I can see a future of LEO satellites with maybe a dozen of these things in them. Put them in orbit against the Earth's rotation and at that ground speed you're talking very quick times to be near your target and you just drop it. It quickly reaches Mach 3-4 and ignites the scramjet at which point it rockets to Mach 10.

I don't know the orbital velocities to do the math but possibly in one hour a single satellite could destroy any target on the planet. Overlap a pair of satellites and you could hit Osama within maybe 20minutes of intelligence arriving. Booyah!

You could launch a rock into space and it would fall back through the atmosphere at mach 10, provided it fell from high enough. Whats the scramjet actually doing then?

No, a rock could not "fall" at mach 10. Terminal velocity for a person is ~80m/s, mach 10 is ~3500m/s. Huuuuuge difference.

Check out the website of the the australian defence science and technology website, they are the people that did it. http://www.dsto.defence.gov.au/news/5118/ . It was propelled 530 km into space (so 330 mile is correct) and then upon re-entry into the atmosphere they started the scram jet and it reached Mach 10. The reason for the extra speed is because as it relies on the airspeed entering the engine to compress the air rather than compressor blades, it can handle much higher internal pressures and hence much more agressive combustion. The problem lies in the reliance on supersonic inlet airflow to start combustion and the extremely short amount of time the fuel has to combust to actually produce thrust before its out of the engine.

They could use maglev technology to accelerate the scramjet instead of rocket to reach supersonic speed. Acceleration is more controlled and safer for passenger I suppose.

With this speed the next world record attempt is not about how fast one can circle the globe but how many times can you circle it in one day.

as a dive bomb because the atmosphere is too thick at low altitudes. WHy do you think the SR-71, other hypersonic planes, and the scramjets have to fly so high? Ever wonder what slows the space shuttle down so much during re-entry?

Even so, a very big rock would have a higher TV, meteors exceed mach 10 - not that thats any worthy comparison

Grant's point about terminal velocity is correct. A rock with a mass similar to the Ram jet in question would reach it's terminal velocity well below mach 1. It's a matter of aerodynamics, fraction and lack of proper mass. A "rock" would have to be the size of the empire state building before it's T. V. would allow it to reach mach 10. However at that speed, it would begin to disintegrate and would lose mass, which would then lower is T. V. and friction would begin to drop it back below mach 10. So the SCRAM/RAM jet is needed to maintain the required velocity. Remember too, that the speed of sound changes at altitude. The speed of sound is different 10 miles up then it is a sea level. At sea level the speed of sound is a certain speed[761.2 mph], but at an altitude of 10 miles it is slower[660.1 mph] because the density of gases is lower. So reaching mach 10 is easier at high altitude than at sea level. Basic physics folks...

Meteors can[and do] travel at speeds well in excess of mach 10, but slow way down once they hit atmosphere and are below mach 1 when they hit the troposphere. The only objects that could maintain supersonic speeds would have to be massive enough to withstand atmospheric fraction. Of course, such an object would cause an E.L.E., or at the very least a severe climate change. A rotational & orbital shift would also be very likely from such a strike...

I have an article on hypersonics in the Sept 07 issue of Air & Space / Smithsonian magazine. Should be out/online soon.

HOW ACCURATELY COULD YOUR SCAMJET DEVEICE BE & HOW MUCH WEIGHT WILL IT CARRY?

P.S. I'm Planning on EXTORTING World for 13 1909 S-VdB Penny, SO I'LL HAVE MOST.

Signed:PHYSICIAN THOMAS STEWART VON DRASHEK M.D.