DARPA: Hypersonic strato-ship crackup was no biggie
Preps second Shuttle-envelope-buster for 2011
Radical Pentagon boffins say they now understand why their hypersonic aeroplane/missile prototype, the Falcon HTV-2, cracked up in flight above the Pacific in April - and say they are on course for another trial flight next year.
Talk about a hot ship
Regular followers of the Register's hypersonics coverage will no doubt recall that the HTV-2 was fired out of the Earth's atmosphere atop a "Minotaur IV Lite" booster rocket stack from the US military's Vandenberg space base in California. The HTV-2 unmanned test vehicle had no propulsion of its own, being intended rather to try out new airframe and control technologies for use in hypersonic weapons or aircraft of the future.
It had been intended that the HTV-2 would then re-enter the atmosphere and make a hypersonic glide under autonomous control to splash down in the vicinity of Kwajalein Atoll, nearly 5,000 miles from the Californian launch site. During the flight, Pentagon boffins from DARPA would learn if their new hypersonic tech - intended to be a major leap forward from that used in existing airframes like that of the space shuttle - worked as expected.
In the event, communications with the HTV-2 were lost shortly after it entered the upper atmosphere as the ambitious craft broke up into blazing supersonic wreckage. Since then, an independent review board of experts - not drawn from the team which designed the Falcon - have been analysing telemetry from the doomed hypercraft.
According to a military statement (pdf) released this week:
Detailed analysis conducted by the [review board] revealed that the most probable cause of the HTV-2 flight anomaly was higher-than-predicted yaw, which coupled into roll thus exceeding the available control capability at the time of the anomaly. The analysis concluded that knowledge of several key aerodynamic parameters in this flight regime was limited.
HTV project chiefs say this means that relatively minor adjustments should make the next Falcon atmo-plunge successful. According to the overseeing bigwig, David Neyland:
“The conclusions of the ERB indicate that no major changes to the vehicle or software are required to mitigate the first flight anomaly. Engineers will adjust the vehicle’s center of gravity, decrease the angle of attack flown and use the onboard reaction control system to augment the vehicle flaps when HTV-2 flies next summer.”
One need hardly add that the agency in charge of the radical speedster is none other than DARPA, the Defense Advanced Projects Research Agency. DARPA is more than just proverbially nutty - mere fruitcakes or even the maximum possible amount of nut containable in a three-dimensional space using powerful squashing machinery do not do justice to the federal warboffinry outfit.
Perhaps one might postulate a gigantic accreted body of nuts many times more massive than our entire solar system floating in space, which would naturally collapse under its own gravity in a cataclysmic snack-based supernova and leave behind a ultradense neutron star made up of collapsed matter originating entirely from nuts. That's how nutty DARPA is.
Taking that into account, readers will realise that there remains a serious chance of another disastrous hypersonic upper-atmospheric prang next year. Even if DARPA's crafty carbon-carbon airframe and nifty new flight regime can be made to work, we may be waiting a while for our brilliant new reusable spaceplanes and Antipodes-in-four-hours hyperliners - there's been trouble with the engine project as well. ®