It would be the fastest aircraft in the world - flying from Auckland to London in less than an hour.
But the hype may just have flown faster than the glider itself.
The Falcon Hypersonic Technology Vehicle was launched today from Vandenberg Air Force Base, 200 kilometers northwest of Los Angeles.
It was supposed to be launched to the edge of space, separate from its booster and maneuver through the atmosphere at 21,000 km/h before intentionally crashing into the Pacific Ocean near the Marshall Islands.
Shaped like the tip of a spear, the small craft is part of a US military initiative to develop technology to respond to threats at 20 times the speed of sound or greater, reaching any part of the globe in an hour.
But shortly after the experimental craft began flying on its own today - contact was lost, the Defence Advanced Research Projects Agency (DARPA) said.
Today's mission was the second of two planned flights. Contact was also lost during the first mission.
Defence analyst John Pike of Globalsecurity.org wasn't surprised with the latest failure because the hypersonic test flight program is still in its infancy.
"At this early stage of the game, if they did not experience failures, it's because they're not trying very hard," he said.
DARPA used Twitter to announce the launch and status of the flight.
The agency said the launch of the Minotaur 4 rocket was successful and separation was confirmed.
It next reported that telemetry the transmission and measurement of data from the glider had been lost.
"Downrange assets did not reacquire tracking or telemetry," the agency added. The craft has "an autonomous flight termination capability," it noted.
No further details were immediately reported. There was no immediate response to an email request to DARPA for information on the mission.