Pentagon releases results of 13,000-mph test flight over Pacific | Hacker News Reader

Pentagon releases results of 13,000-mph test flight over Pacific

latimes.com

61 pointssunsu48 comments

The stated goal is apparently to be able to strike anywhere on earth within an hour. What's the advantage of something like this above an ICBM? I can imagine one advantage would be that the target can't be easily inferred from the flight path? Also an ICBM launch is immediately associated with a nuclear attack, while this might not be? Although I could imagine an enemy detecting multiple of these hypersonic vehicles heading towards it, wouldn't want to wait to find out.

I thought the goal was to evevtually build a plane that could be anywhere in the world within an hour. There are many more uses for this, of course. Next generation SR71 Blackbird, fire missiles on enemy vehicle, sink pirate ship, etc.

Yeah, but consider: the SR-71 was intended to replace the U-2. Which one was retired? Which one is still in active use?

They were both made obsolete by satellites and now drones.

Disagree: the reasons why the SR-71 was retired, and the U-2 is scheduled for retirement, are not technical but political and fiscal.

I don't really believe that either.

Improved missiles are now able to shoot down the U2, and maybe get close to the SR-71. That makes these planes a liability now, when over developed territories such as the former USSR.

Both were formerly useful, and have been brought out of retirement, when required for tasks that a satellite could not perform, or was not in position for.

I wouldn't be surprised if the x37 mini-spaceplane was primarily useful as a surveillance platform.

Improved missiles are now able to shoot down the U2

This has probably been true since at least 1960.

I wouldn't be surprised if the x37 mini-spaceplane was primarily useful as a surveillance platform.

Eh. It takes an Atlas V to launch the X-37.

At 90 million a launch, and months to prep, it's not exactly something one can crank out with a frag order on a day's notice.

With multiple kill vehicles that are capable of repositioning themselves in flight (like the ones shown here: http://www.youtube.com/watch?v=B9mNNA2gEF8), I don't even think you can call that an advantage.

The only advantage I can think of is the possibility of a return flight, but that only matters if reuse is economical vs an expendable vehicle (probably not), or if the cargo is "precious", i.e. a human. Given the prevalence of drone aircraft (including some that can stay airborne indefinitely), increasing capability of satellite optics, and literally decades of refinement on ICBMs, I'd have to say that this pursuit is more likely purely for research. (Of course, as a researcher you always have to "sell" your experiments to the decision makers with lines like "strike anywhere in under an hour".)

Nuclear weapon use is no longer warranted and big nation/states like the US, Russia and China will definately not be using them for any kind of attacks. This Mach-20 glider is for a more targeted attack. A similar concept is presented in "The Gold Coast" by Robinson, where a hypersonic glider tracks and destroys target using only kinetic energy (no explosives). This also allows you to hit targets in high-density (ie. urban) environments without affecting the surrounding area.

Mutually Assured Destruction is alive and well and many countries still maintain a good stock of nuclear weapons for this purpose.

A vehicle like this can be controlled for more of it's flight phase, giving more flexibility in targeting moving objects, or strikes of opportunity. Also, as you said, this is less likely to start World War III.

> Also an ICBM launch is immediately associated with a nuclear attack

You got it. An ICBM would set off early warning alerts about a nuclear attack, prompting a possible counter-attack.

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

The lifter rocket costs $50mil, so there are few targets in the world worth throwing this hardware at.

Have you looked at the US's defense budget? When you have money like this you don't need to worry too much about practical uses. Imagine if this money went unspent, Americans would get a tax break or heaven forbid better healthcare or something.

Seriously, a good chunk of what the US researches is done strictly because we don't question the defense budget and the contractors and bureaucrats know how to game the system and create jobs/fortunes for the defense industry.

As far as the whole "herp derp its not an icbm," well something tells me that if the Chinese had this and hit our carrier groups with it(1), we'd respond with nuclear strikes instantly. If we send 10 of these towards downtown Beijing, its nuclear war as usual fellas. I think the subtleties between kinetic and nuclear will be lost on the generals and leaders who make retaliatory strike decisions.

(1) The PRC is playing with all manner of kinetic kill vehicles and probably have a carrier killer mounted on several warships and subs, so this isn't purely conjecture

Lets not get too carried away here. At least in the US, the defense department, specifically DARPA, invests a lot in research that doesn't have immediate value but has a proven track record for being invaluable years or decades later.

50 years ago someone might have made an argument that investing 380m in health care would be more useful than some crazy thing called 'ARPANET', but i think in the end it turned out better for everyone. Add GPS and self-driving cars to that list too.

If ARPANET failed then some other network would have evolved into the internet. Its not like networking technology was unknown outside of the military, heck most advances in networking and CS happen in universities, not via defense contracts.

Heck, the French had Minitel in the 80s while we had a loose network of BBS's and to be frank it wasn't the lack of network technologies that was the problem back then, it was the lack of a killer app. TBL delivered that in the form of the WWW. The WWW is network agnostic. There wasn't a day when people went "Whoa, T1s are now affordable for my LEC to sell to my ISP, I better get a shell account pronto!" It was "Whoa, there's email and colors and pictures and text and even video on my computer's modem via this thing called the web I'm seeing advertised on movie trailers and on product packaging?!?!"

... and who do you think funded those CS departments? It's all by grants, a lot of which is from the defense department, who has a lot of money to invest in high risk, high return, long-running projects with practical outcomes.

Saying 'some other network would have evolved' is a cop-out: clearly that would have happened, but it would have happened later and that could have cost us in terms of competitiveness. Same argument for GPS, except even more likely given the heavy investment in infrastructure needed to even get a basic implementation running.

Also the 80's are not the 60's, it's ridiculous to think that the networking technologies were not influenced heavily by the work funded by the military ... hell the only reason killer apps could be created was because the technology was so pervasive that it made sense to write them.

And GPS, self-driving cars, and ARPANET are only what I came up with offhand because I was too lazy to check. Add ENIAC and radar to that list, both of which were developed specifically for military purposes but (obviously) later had wide-ranging practical civilian applications.

>It's all by grants, a lot of which is from the defense department,

A lot? Some? Very little? Unless you have some backup here, the whole "HERP DERP EVERYTHING IMPORTANT IS FINANCED BY THE DOD" is wearing pretty thin.

In 2010, 227 million over 5 years:

http://www.defense.gov/releases/release.aspx?releaseid=13717

Also I didn't say everything important, I said a lot. In hindsight, I don't think anyone thinks funding ARPANET or ENIAC was a bad idea...

Yeah but whats the context? How much of that directly to programs like we're talking about vs money via tuition, fees, etc.

I think this is really impossible to quantify, but from a rational POV we can look at countries with small defense spending and see that they have healthy univerisities and healthy economies as well as healthy technological advances (again my example of the early french 'internet'). Tim Berners Lee was not only NOT an American but not funded by the DoD. His www application is what got the ball rolling. The network or protocol didn't matter, we can run http over anything. Same with Linus Torvalds, another non-American non-DOD funded star. We were sitting on nice networking tehcnology and wondering when Joe Public would see the wisdom of anything other than AOL and dialup (two very American things). It took a an Englishman at CERN and a Finnish student to give us WWW on Linux. Whats the Finnish defense budget look like?

A big bloaty DoD and the war on brown people is not a requirement for technological progress. If anything, it holds us back.

> A big bloaty DoD and the war on brown people is not a requirement for technological progress. If anything, it holds us back.

You're confusing procurement costs with R&D. Lumping all military spending together is ignoring the subtleties as to why and how the money is used:

http://www.thecollaredsheep.com/wp-content/uploads/2010/04/d...

* Tim Berners Lee got the ball rolling on www decades after the ARPANET investment, that doesn't help your point.

* The English have large military R&D spending, given their GDP, and always have.

The technological feat seems amazing! But .. my English parser crashes here:

“The initial shock wave disturbances experienced during second flight, from which the vehicle was able to recover and continue controlled flight, exceeded by more than 100 times what the vehicle was designed to withstand,” DARPA Acting Director Kaigham J. Gabriel said in a statement. “That’s a major validation that we’re advancing our understanding of aerodynamic control for hypersonic flight.”

Is he saying that (my understanding) the shock wave disturbances exceeded the designed/expected maximum by a factor of 100? And claims that this is supporting the idea of understanding hypersonic flight so much better?

I _think_ he wants to say 'In spite of these troubles we were able to recover, due to our good understanding of the underlying principles' but I parse it as 'The outcome of the experiment showed that we greatly underestimated the forces involved and this clearly validates our understanding'.

Can some native speaker point out were I stumbled?

I believe he is trying to say their ability to recover from such a large variation from their initial expectation is proof that they truly understand/are advancing in their knowledge of hypersonic flight. That said, since there is a break between the two quotes the second could have come 10 sentences later and the writer could have unknowingly dropped context/information in some omitted statements. It is a bit of a hard to parse statement, but that is what you get from people, rarely do people speak in memorable, concise sound bites 'off the cuff'.

He didn't say that it validates our understanding, he said it validates that "we're advancing our understanding." It sounds like they learned quite a lot from this experiment, including some big surprises.

Native speaker here. I think you're correct that it's somewhat contradictory. Gabriel says two things: 1) They were off by a factor of 100 in predicting the shock wave disturbances, and 2) The vehicle was able to recover.

I think his comment about advancing understanding is more referring to (2) than (1), although now that you point it out, it's hard to say you understand something well if you're off by two orders of magnitude...

Here's a TED talk by Regina Dugan that discusses these flights as well:

http://www.ted.com/talks/lang/en/regina_dugan_from_mach_20_g...

Great talk, thanks for the link.

The juxtaposition of toddlers and the "DARPA" logo is not jarring, given the benefits DARPA has produced for humanity due in part to its unleashed creativity, but certainly 'weird' given the context of its mission statement.

In the video it looks lik the htv is controlled by two flaps on the bottom. Even if this program is in fact finished the research will be useful at some point when rockets are cheaper. A 12 minute flight coast to coast would be nice.

I still can't even fathom a 12-minute separation between Los Angeles and New York.

Plus two hours getting to and waiting at the airport.

Maybe that'll be solved by the time I can afford a hypersonic flight between NY and LA.

It is a solved problem. At least getting to the airport. Now we just need to make it more affordable.

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

I think the OP is instead refering to the standard disclaimer to arrive 1-2 hours before your flight to get through baggage check, security, and sitting at the gate.

Don't forget about the time sitting on the tarmac.

That would be amazing. I'd imagine it would be something like the difference between transatlantic travel by sailboat and today's jets.

The technologist in me says that is pretty awesome.

The cynic looks at $320M price tag and wonders why I don't have better schools for my kids and DARPA doesn't have a better video of this thing.

What makes you think they don't?

Would $320M make much of a difference? The city of LA just spent $500M on a single school building.

I wager had the money gone towards education, we would either have a $820M school building or a second one worth $320M.

When the technology does start to work, could this have civilian applications one day?

In theory, yes. But the fastest civilian plane, the Concorde, was shut down years ago. There's cost/benefit ratio that needs to be met.

Let's not forget the concord was shut down mostly because one of them ran over a 17 inch bit of titanium that sent pounds of debris flying at the plan at 500mph rupturing a fuel tank and causing it to blow up. The next year some a-holes flew into buildings in NY and the pentagon and put the airline industry and economy into a tailspin.

http://en.wikipedia.org/wiki/Air_France_Flight_4590

I think that crash was more the excuse they were waiting for. Economically, it was past its prime, a prime at which I do not think it ever brought in much money, if at all. http://en.wikipedia.org/wiki/Concorde#Operational_history, for example, claims "By around 1981 in the UK, the future for Concorde looked bleak. The British government had lost money operating Concorde every year, and moves were afoot to cancel the service entirely". It also says "It is reported that British Airways then ran Concorde at a profit, unlike their French counterpart", so there may have been years it was making a profit, but Concorde was flying for prestige, not for the money.

I also think that 500mph figure you give is incorrect. Wikipedia lists Concorde take off speed as 250mph, and http://en.wikipedia.org/wiki/Air_France_Flight_4590 talks of 500kph, or 310mph.

Of course. Concorde was shut down for economic reasons.

But it was also the first interaction of the concept, and built with very inefficient technology. The Space Shuttle flew for the first time 5 years after Concorde began commercial service.

How many improvements have we seen in commercial aviation technology: better engines, better aerodynamics (and CFD), lighter materials, fly-by-wire

If a new SST is ever designed it will probably sill be inefficient, but ahead of the original Concorde. You probably wouldn't need it to go Mach 2 for example, maybe Mach 1.5 saves enough time on a trip to justify it.

Not to mention the issue that Concorde had Economy class seats with First class price.

> The Space Shuttle flew for the first time 5 years after Concorde began commercial service.

That just blew my mind. I had no idea the Concorde was so old.

There is also the related problem of reducing the sonic boom. One of the reasons why the Concorde was so expensive was because there are so few routes that it actually makes sense to use the Concorde on. Even today, we can add a few more routes that makes sense (thanks to China's growth), but even then, the limited route options would mean a relatively low demand for airframes, thus an inability to take advantage of economies of scales (which are super important in aviation, since R&D costs so goddamn much).

It's possible that Concorde was given a mission, for political reasons, that made no sense.

Cut the flight time NYC > London in half. Big deal: it's only seven hours. Three or seven the day is pretty much spent in travel.

Where they - my opinion - should have aimed Concorde was the Pacific.

LA to Sydney is a 14 and 1/2 hour flight. Cut that to seven? Put another shrimp on the barbie.

Granted, the actual Concorde we got did not have the range. I wonder if the designers could have done something about that.

Accelerating the human body to mach 20 has its own set of problems. Namely, the g-force involved. A mach number is dependent upon altitude, but they mention 13,000 MPH in the article. This is a little bit slower than the orbital velocity of the Space Shuttle (around 18,000 mph), but at these speeds, rocket launches are the neighborhood we're operating in.

Wikipedia says Shuttle astronauts experience around 3 Gs. This isn't intolerable, but g-force tolerance is heavily related to time spent at a specific level. Astronauts are screened for tolerance to g-forces as part of their selection criteria. It is unlikely that the general public would ever ride in aircraft that subject passengers to the forces commonly felt during the launch of an orbital vehicle.

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