
Military Aircraft Hit Mach 20 Before Ocean Crash, DARPA Says - Shalle
http://www.space.com/12670-superfast-hypersonic-military-aircraft-darpa-htv2.html
======
51Cards
August 18th, 2011? Possibly a few tests after this have already happened?

Edit: Looks like no third flight yet. Found this followup:
<http://www.darpa.mil/threeColumn.aspx?pageid=2147485247>

Also found this paragraph to be interesting:

“The initial shockwave 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,” said DARPA
Acting Director, Kaigham J. Gabriel.

~~~
akavel
And this: "[G]radual wearing away of the vehicle’s skin as it reached stress
tolerance limits was expected. However, larger than anticipated portions of
the vehicle’s skin peeled from the aerostructure."

And, dated: April 20, 2012

~~~
iandh
The "gradual wearing of the vehicle's skin" is called is called ablation.

Its a standard way both hyper sonic and reentry vehicles manage heat.
Basically the skin boils off creating a pressure wave that the vehicle flights
behind.

Wikipedia has a good description of it.
<http://en.wikipedia.org/wiki/Atmospheric_reentry#Ablative>

------
Retric
Depending on what kind of impact angle they can achieve they may not need to
add high explosives to this. Mach 20 is 400 times the kinetic energy of mach 1
and 40,000x the kinetic energy of a 76mph collision. So, even a 100lb craft =
1,000 times the impact energy of a 4,000lb truck at highway speeds.

~~~
saosebastiao
Interesting perspective...I hadnt even thought of the possibility.

~~~
AUmrysh
Kinetic Bombardment has been a sci-fi concept for decades, and it's
interesting to see a real, possibly cost effective, technology that could make
it real. At those speeds, you don't need explosives, just a lot of mass to
slam into something.

~~~
Zarathust
According to project Thor, it would not be that cost efficient. The wikipedia
page states that the rods would need to be at around 8 tons. A ton of tungsten
is around 50k$ so 8 tons is rather negligible. What is very expensive is to
get 8 tons of material to space. During the space shuttles era, bringing a
kilogram of matter to space would cost around 20k$. A ton is 907 kilograms.

8 x 907 x 20 000 = 145M$ per payload.

I don't have the exact numbers for the cost of an ICMB with a nuclear warhead
but I'm pretty sure that it is less than that. We also didn't factor in the
cost of maintaining an orbital launcher, possibly manning that thing and other
costs which being in space incur.

Maybe with newer launch methods bringing goods to space will be cheaper, but I
don't think we'll see this kind of tech unless costs decrease to around
2000$/kg to space (1/10th of what it is now).

<http://en.wikipedia.org/wiki/Kinetic_bombardment>

~~~
duaneb
Well we are reaching an age (of asteroid mining) where it's probably more cost
efficient to manufacture in space and ship (or railgun, I guess) the mass to
earth. Probably not for a while, but I don't think it's science fiction
anymore.

~~~
AUmrysh
That gives me an interesting idea. Do you think it could be feasible to mine
ore from space and then drop-ship it to some low-depth (a few hundred feet at
most) part of the ocean? The heat from re-entry would likely turn the metal
into a molten blob, and the sea water would rapidly cool it.

~~~
duaneb
Can they guide things that accurately without assisting it mid-flight? If so,
that's a cool idea, dunno if it's actually practical.

------
zeteo
>HTV-2 is part of an advanced weapons program called Conventional Prompt
Global Strike, which is working to develop systems to reach an enemy target
anywhere in the world within one hour

They're getting really close. Mach 20 is about an hour and a half to the
opposite point on Earth.

~~~
lifeisstillgood
I read this too, but my first thought was "if this had been Iran we would have
invaded at midnight".

Its cool tech, yes, but really...

~~~
rayiner
Of course and that would've been the sensible thing to do. As Americans, we
want a world where the U.S. is the one that has this technology, not countries
who aren't the U.S. Our standard of living (1/4 of the world's resources for
5% of the world's population) literally depends on that state of affairs.

~~~
danielweber
The US doesn't need military dominance to have 1/4 of the world's consumption.
It needs to be able to pay people who have 1/4 of the world's production
enough that they sell it to us. And about 80% of that latter group are
Americans anyway.

~~~
rayiner
That works until the country that does have military dominance decides to
conquer you and take that production for itself. The market is meaningless
when force can be used to take what you can't purchase in the market.

It is possible to be a wealthy nation that doesn't have military dominance
(Switzerland, etc). The key is to be overall small enough that you can consume
a lot per capita but still fly under the radar of the big boys. A country as
big as the U.S. doesn't really have that choice.

~~~
danielweber
Okay, I think I misread you. The meme of "the US only has 5% of the world
people but consumes 25% of the world's resources!" is usually said by people
who think it's "unfair" that the US is consuming "so much."

If you are saying that the US needs military dominance because we need to
protect our own domestic production from invasion, that's something else. I
still disagree but not as forcefully as I would to the other characterization.

(If an invader tried to invade America for the purpose of seizing our wealth,
much of it would evaporate instantly. They can capture factories but more and
more of it is IP that a potential invader could just stay home and pirate
instead.)

~~~
duaneb
Why is it you do not care about the US consuming that much? Do you not care
that 96% of the world only has 75% of the world's resources? Are you really so
centered on yourself and your culture you literally want us to exploit the
rest of humanity?

I don't think it's unfair, just morally despicable.

~~~
rgbrenner
The US produces 22% of the world's GDP. There's nothing despicable about
consuming what you are producing.

What is despicable is people who think they are entitled to the labor of
others for free.

~~~
duaneb
> There's nothing despicable about consuming what you are producing.

I agree, what's despicable is ignoring the rest of humanity. No, there's no
entitlement (whatever that means really, a pejorative term for rights), but I
do think you have a moral obligation to help people who need it.

~~~
danielweber
I want China and India and Africa to have first-world standards of living,
with similar per-capita GDPs. That will be awesome, both for them as well as
for the US and Europe.

~~~
duaneb
Yes, standards of living is the big thing, and not just across china, india,
and africa. I would be fine with the US's dominance if I though other people
in the world could have satisfying lives where they don't have to worry about
employment (and the resulting food, shelter, health care). But, we are
probably decades from achieving that in even China and India, both of which
have a lot to offer the world even now.

Unfortunately, the US also has many inherent resource advantages (pretty
amazing farming, for instance), which much of the rest of the world doesn't
have. I really don't see at least the arid parts of Africa competing any time
soon on material goods, and they don't have the education or cultural draw to
attract production of intellectual goods. So at some point, the world does
need to help itself out. It's not just going to magically fix itself without
people helping each other.

I guess I should make this clear: I'm not advocating some kind of world
socialism thing. I'm pretty sure things like classes are inherent in human
societies. But I would like to drastically reduce the difference between the
poorest and the richest people, and I do want to make sure that the basic
things we take for granted in the US are available everywhere.

------
jvzr
Recent follow-up to the parent's old article:
[http://www.space.com/15388-darpa-hypersonic-glider-demise-
ex...](http://www.space.com/15388-darpa-hypersonic-glider-demise-
explained.html)

~~~
unwind
More recent, but still 11 months old. It's pretty cool to look at the
trajectory maps while remembering that the flight lasted 9 minutes Mach 20
(around 7000 m/s) is _fast_. :)

------
cadetzero
I found it really interesting to read about the underlying tech, scramjets:
<http://en.wikipedia.org/wiki/Scramjet>

~~~
hencq
I don't think the HTV-2 uses (or used rather, since this was in 2011) a
scramjet though, but uses a rocket engine. The HTV-3X was supposed to use a
scramjet it seems, but that was cancelled.

<http://en.wikipedia.org/wiki/DARPA_Falcon_Project>

~~~
cadetzero
As I understand, you can't hit those speeds with just a rocket engine. The
HTV-2 is considered a rocket glider - it needs a rocket to propel it to
altitudes and speeds where the SCRAMJET can kick in (as the scramjet itself
has no moving parts).

~~~
ballooney
You can hit those speeds and beyond with a rocket engine. They don't really
have a speed limit, they'll keep accelerating something (provided their force
is greater than the drag and any other retarding forces) until you turn them
off. Eg, a payload into earth orbit, which would be about Mach 25 if there was
some atmosphere. Or significantly faster if you're putting a probe on an
escape velocity, for example the Pluto probe New Horizons, which was launched
with a solar escape velocity that would be equivalent to about Mach 50 (all
sea level).

The advantage of the scramjet over a rocket is that you don't have to carry
the oxidiser in a tank with you (like a conventional rocket). You get it from
the atmosphere. But being inside an atmosphere making thermal management a big
challenge, as the article describes.

------
will_brown
I am almost positive I have video of this aircraft. I took night video
(1/13/13) of an aircraft near the Everglades, the aircraft moves so fast it
appears that I am moving, but I was stationary. When I get home I will upload
the video and add a link here to see if people agree.

~~~
iandh
There as yet to be a third flight. DARPA is surprisingly open about the Falcon
HTV-2 test flights. The releases have included more info that I would have
expected.

DARPA was actually live tweeting the 2nd flight.

~~~
will_brown
Here is the video:
[http://www.youtube.com/watch?v=f3VqiPhsnMM&feature=youtu...](http://www.youtube.com/watch?v=f3VqiPhsnMM&feature=youtu.be)

As "open" as DARPA is they are subject to confidentiality and are only allowed
to disclose what the DoD allows them to disclose. I am no conspiracy theorist
but compare the shape/light of the aircraft in my video to the artist night
time rendition from the OP article. Even if the aircraft in my video is
different, I can tell you I have never seen anything anywhere near as fast as
the aircraft in my video including F-15's, F-16's, F-18's or the space shuttle
when it lands (which breaks the sound barrier at very low altitude).

~~~
iandh
Thanks for sharing the video. Yeah, while its not Falcon there are tons of
classified launches coming from the Cape. Do you remember if the vehicle was
flying south or east?

~~~
will_brown
Sorry for the misunderstanding, the video is not from the Cape but the Eastern
edge of the Everglades around South Miami. The aircraft was traveling North,
seemingly along the edge Everglades.

There is a Air Force Base very near (10-15 miles)in Homestead, FL and a Navy
Base in the Keys (over 100 miles), still it not unknown for the Navy to do
exercises that far North, but I _think_ a single aircraft at night might be
unusual.

------
colinshark
If the US is going to field these weapons, we need to be cool with Russia and
China tossing around non-nuclear ICBMs- because that is what this is.

~~~
Thrymr
> non-nuclear ICBMs- because that is what this is.

Well, no, it's not. It's not a missile, it's not ballistic, and I don't know
if the range is truly intercontinental. Not that the Russians and Chinese
won't be concerned, but it is a rather different thing (and a much harder
engineering problem).

~~~
EwanToo
You're right it's not a ballistic missile, but it's end goal is in many ways
the same:

"Prompt Global Strike (PGS) is a United States military effort to develop a
system that can deliver a precision conventional weapon strike anywhere in the
world within one hour, in a similar manner to a nuclear ICBM"

<http://en.wikipedia.org/wiki/Prompt_Global_Strike>

------
ry0ohki
It did the equivalent of Boston to North Carolina in 3 minutes. Crazy testing
something that covers so much distance so fast.

------
will_brown
I commented earlier that I thought I recorded this aircraft at night on
(1/13/13), people already bashed me saying this aircraft has only flown 2
times blah, blah, blah... (ever hear of military testing? They don't tell the
public)

Here is the video:
[http://www.youtube.com/watch?v=f3VqiPhsnMM&feature=youtu...](http://www.youtube.com/watch?v=f3VqiPhsnMM&feature=youtu.be)

Why do I think it is same aircraft? When reading the OP article I immediately
identified the artists night time rendering as the same aircraft I recorded in
the video (video quality does not do it justice, but in person I can verify it
looked identical to the artist rendering). Separately, the aircraft I recorded
is by far the fastest thing I have ever seen, not in some UFO conspiracy way,
but that I fly aircraft, attend airshows (F-14, F-15, F-16, F-18), saw Space
Shuttles land (breaks sound barrier at low altitude) and I can saw I have
never seen anything move as fast as the aircraft in my video.

------
quarterto

      Darpa Maintains Control of Unmaned Aircraft at Mach 20 
    

...for three _whole_ minutes!

~~~
melling
Sounds like a lot to me. For the first DARPA Grand Challenge, for example, no
car finished the race. The farthest went 7 miles.

<http://en.wikipedia.org/wiki/DARPA_Grand_Challenge_(2004)>

The next year 5 vehicles completed.

<http://en.wikipedia.org/wiki/DARPA_Grand_Challenge_(2005)>

Also, consider all of the rocket failures in the 1960's and we still made it
to the moon by the end of the decade.

------
run4yourlives
Pretty sure this is 'old tech' because of the successful test of the Advanced
Hypersonic Weapon.

The Prompt Global Strike program seems to have moved on to other options.

<http://en.wikipedia.org/wiki/Prompt_Global_Strike>

------
axus
Watching that video feels like something out of Kerbel Space Program:
<http://www.youtube.com/watch?v=DWBgUnL_ya4>

------
baby
mach 20 = 24 500.88 kmh (~6800m/s)

This is incredibly fast. Distance New York to Paris : 5851km[1] it would take
14 minutes for this plane to do the distance.

[1] <http://www.wolframalpha.com/input/?i=paris+to+new+york>

~~~
pkfrank
Why do we even reasonably need something this fast?

Wouldn't it be much more cost-effective to merely link up with strategic
partners in other countries (Germany / Israel; Philippines; etc.) to give us
the distribution we need for "conventional" missiles that would hit in the
same timeframe?

~~~
mpyne
Missiles can be shot down by state actors, non-state actors can hide deep in
areas which are out of range of the U.S. or its allies. But launching anything
on an ICBM makes it almost impossible for other nations to distinguish from a
nuclear missile launch.

Of course, if Prompt Global Strike is capable of carrying cargo with it then
maybe countries like Russia or China would suspect it can _also_ carry a small
nuclear warhead, so it may be that concern doesn't completely go away.

~~~
duaneb
I don't think it's in any country's interest to do a nuclear attack with
anything but a blow that would cripple response, a small nuclear warhead seems
like an invitation to go from tolerated and accepted to hated.

------
sabertoothed
Why does it not have a mane?

~~~
metageek
It did have one, but it ablated.

------
tocomment
When is the next test?

