On its fourth and final flight, the X-51A Waverider made history last week: the longest flight ever for an air-breathing scramjet engine.

An Air Force B-52 dropped the unmanned test vehicle from about 50,000 feet over the ocean off southern California, after which it flew more than 230 nautical miles in about six minutes. Top speed: Mach 5.1.

The Air Force has no immediate plans for follow-on tests. But in this Boeing promotional video, Joseph Vogel, the company’s director of hypersonics, explains the technology’s promise:

Now DARPA has had more time to go over test data collected by more than 20 sensors positioned on the ground, sea, and air during the August flight. And while still stingy with details about the cause of the premature shutdown, an agency press release says that the Falcon did in fact achieve stable, aerodynamically controlled Mach 20 flight for nearly three minutes, as initial data suggested.

DARPA even produced video, taken from a tracking ship in the Pacific.

And just for fun, here’s an animation showing how easily the HTV-2 would blow past an F-18 poking along at Mach 1.5.

Well-earned retirement: Atlantis heads into the hangar after its last spaceflight.

For the Memorial Day weekend, an assortment of news from the world of air and space:

►  The field of hypersonic flight has a new record: The Air Force’s X-51A Waverider reached Mach 5 in a 200-second scramjet engine burn over the Pacific on Wednesday. Video below:

►  What looked at first like a small asteroid circling the sun may in fact be an old Soviet rocket stage from the failed Luna 23 sample return mission in 1974. It may come back to hit us in 2036 (the nerve!) but it’s too small to do anything but burn up in the atmosphere.

►  The Stratospheric Observatory for Infrared Astronomy (SOFIA), an airborne telescope created by NASA and the German Aerospace Center, registered “first light” Wednesday night. Here’s a video of some of the pre-flight preparations and the takeoff. And here’s a shot of Jupiter taken during the flight.

► Tomorrow is the 23rd anniversary of 19-year-old Mathias Rust’s daring (dumb?) landing in Red Square, still one of the most talked-about aviation stunts in history.

►  And after racking up more than 120 million miles during 32 orbital flights over 25 years, the space shuttle Atlantis came back to Earth for the last time on Wednesday, capping the STS-132 mission to the International Space Station. Commander Ken Ham made a particularly soft touchdown:

Mach 20! Yee-hah!

The field of hypersonic flight research is about to get a boost—actually, two boosts. DARPA’s Falcon Hypersonic Technology Vehicle, or HTV-2, is due to launch Thursday on a Minotaur rocket from Vandenberg Air Force Base in California (after two days of weather delays).

The unpowered glider will be released from the rocket to fly back through the atmosphere, and is expected to reach at least Mach 20 before slamming into the Pacific Ocean near Kwajalein Atoll. On the way down, it will send back lots of data on basics like structural heating, navigation and aerodynamics. The flight should last just 30 minutes, and will be followed by a second Falcon test early next year.

Then, later this spring (no sooner than the end of May), the U.S. Air Force’s X-51 WaveRider is due to begin a series of flights from Edwards Air Force Base. Here’s a preview: