WASHINGTON — The U.S. Defense Department’s first test flight of a new hypersonic glider ended abruptly as communications with the vehicle ceased mid-flight, a setback in the Pentagon’s pursuit of a highly precise long-range strike weapon.

The Defense Advanced Research Project Agency (DARPA)’s Falcon Hypersonic Technology Vehicle (HTV)-2 program is one of three designs in the running to serve as the basis for the Conventional Prompt Global Strike weapon the Pentagon wants to build in order to hit a target anywhere in the world within an hour with a non-nuclear munition. The first of three planned HTV-2 flight tests took place April 22.

The delta-wing-shaped carbon fiber aircraft was launched to the edge of space aboard a Minotaur 4 rocket that also was making its maiden flight. The Lockheed Martin-built HTV-2 craft separated properly from the rocket’s faring and began a screaming glide over the Pacific Ocean intended to cover some 5,700 kilometers in less than half an hour. Nine minutes into the flight, contact with the vehicle was lost, and the cause of the failure is still under investigation, according to an April 23 DARPA press release.

Plans to launch the second HTV-2 craft in early 2011 have not changed, DARPA spokeswoman Johanna Jones said April 26. The second craft will fly a faster and more demanding flight profile.

The administration of U.S. President Barack Obama has made clear its intention to maintain the nation’s strategic deterrent while reducing its dependence on nuclear weapons. As such, the New START nuclear arms reduction agreement signed with Russia on April 8 will not constrain any current or planned conventionally-armed ballistic missiles, according to an April 8 fact sheet posted on the U.S. State Department’s website.

The Defense Department for several years has sought a new non-nuclear weapon that can carry out precision strikes anywhere on the globe. One recent effort to place conventional warheads on submarine-launched Trident D5 missiles was scuttled by Congress over concerns that they could be mistaken for nuclear-armed ICBMs.

The Air Force and Army are each designing different options for Conventional Prompt Global Strike with funding from the Office of the Secretary of Defense. Congress appropriated a total of $165.6 million for the projects this year, and the Pentagon has requested $239.8 million for 2011 and a total of $1.7 billion through 2015, budget documents show.

The Air Force Space and Missile Systems Center is leading one development program called the Conventional Strike Missile. In addition, the Air Force will pick up where DARPA leaves off with HTV-2. In 2008 the service tapped Lockheed Martin to build a third HTV-2 aircraft that will carry a conventional weapon in a flight test.

“Right now we’re in demonstration mode, but the signs I’m reading tell me we will probably move forward ultimately with a conventional strike missile program,” Air Force Lt. Gen. Tom Sheridan, commander of the Space and Missile Systems Center, said in an April 14 media briefing at the National Space Symposium. “The demonstration we’re being asked to do, that we’re working on at this point in time, is to take an HTV-2 and then to put a conventional warhead in the front end of it and launch that downrange and plan to be able to hit a specific point with the munition.”

When the contract for the third HTV-2 craft was issued, Lockheed Martin was required to have it ready for flight testing in 2010. Defense Department spokeswoman Wendy Snyder was unable to say when this test is now planned to take place.

The Army Space and Missile Defense Command is leading a competing effort called the Advanced Hypersonic Weapon, which also would use a hypersonic glider to deliver a conventional payload, but would have a shorter range than HTV-2 and thus have to be forward-deployed. The Advanced Hypersonic Weapon has not yet been flight tested, and Army spokesman John Cummings could not provide any details about the test plan.

Regardless of the type of payload delivery vehicle that is chosen for Conventional Prompt Global Strike, the system will need booster rockets. Orbital Sciences Corp.’s Minotaur family of space launch vehicles, which are based on excess ICBM motors, are a likely candidate for the weapon, according a government source.

Another option the Pentagon may consider are the Athena rockets Lockheed Martin and Alliant Techsystems recently announced they plan to reintroduce. The companies said in March that upgraded versions of the solid-fueled rockets originally developed in the 1990s will be made available to launch small satellites.

In January, Lockheed Martin responded to an Air Force solicitation for small launch vehicles and identified the Athena rockets as a viable platform for Conventional Prompt Global Strike, company spokeswoman Joan Underwood said in an April 20 e-mailed response to questions. Lockheed Martin believes Athena can sufficiently “accommodate the required payload mass and volume and provide ample range capability,” she said.

The Defense Department is now studying all options for a U.S.-based Conventional Prompt Global Strike weapon within the context of a portfolio of non-nuclear strike weapons that includes land- and sea-based missiles and long-range and standoff bombers, according to the State Department fact sheet. This analysis will conclude this summer in time to inform the Pentagon’s 2012 budget submission, it said.