Pegasus Launches HETE

Ten years ago today — October 9, 2000 — a Pegasus rocket launched the High Energy Transient Explorer (HETE 2) over the Kwajalein Missile Range in the Marshall Islands.


(Front view of the HETE-2 spacecraft mounted on the Pegasus rocket, before shroud installation. NASA image.)

Including an array of instruments from the U.S., France, and Japan, HETE-2 was designed to investigate cosmic gamma-ray bursts, “the biggest explosions since the Big Bang” according to this press release. HETE discovered that

The distinctive signature [of a short gamma-ray burst] is that of two neutron stars or a neutron star and a black hole merging, followed by a colossal explosion.

You can read more about the HETE mission on this NASA page and this MIT page.

The first HETE spacecraft had been placed in orbit by a Pegasus rocket on November 4, 1996, but it did not separate from the third stage and so was unable to perform its mission. The Pegasus for this mission originated out of Vandenberg AFB and was launched over Kwajalein from its L-1011 carrier aircraft.

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A Space DART That Hit Its Mark Too Hard

Five years ago today — April 15, 2005 — the “Demonstration of Autonomous Rendezvous Technology” (DART) spacecraft was launched by a Pegasus-XL rocket from Orbital Sciences Corporation’s L-1011 carrier aircraft flying out of Vandenberg AFB.


(Technicians prepare the DART spacecraft for flight. Orbital Sciences Corporation image from http://www.msfc.nasa.gov/news/dart/. Click to enlarge.)

The DART spacecraft was meant to rendezvous with and maneuver around the Multiple Paths, Beyond-Line-of-Sight Communications (MUBLCOM) satellite; however, the mission was not successful.

From the mishap investigation report,

DART performed as planned during the first eight hours through the launch, early orbit, and rendezvous phases of the mission, accomplishing all objectives up to that time, even though ground operations personnel noticed anomalies with the navigation system. During proximity operations, however, the spacecraft began using much more propellant than expected. Approximately 11 hours into what was supposed to be a 24-hour mission, DART detected that its propellant supply was depleted, and it began a series of maneuvers for departure and retirement. Although it was not known at the time, DART had actually collided with MUBLCOM 3 minutes and 49 seconds before initiating retirement.

I don’t know if they characterized it as a “successful failure,” in that they learned something useful from it, but it’s important to try these things, even if some of them fail. As I heard Howard Hendricks say many years ago, “If you’re not falling down, you’re not learning to ski.”

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First Pegasus Launch, Twenty Years Ago

On April 5, 1990, the first live launch of a Pegasus rocket carried the PEGSAT experimental satellite into orbit.


(July 1991 picture of a Pegasus rocket being carried by NASA’s B-52. NASA image.)

PEGSAT was an interesting combination of an instrumentation package to monitor this first Pegasus launch; a small Navy communications relay satellite; and a science experiment involving the release of barium to observe “interactions of photoionized barium with magnetic and electric fields in the Earth’s magnetosphere and ionosphere.”

The Pegasus rocket was carried aloft from Edwards AFB and released by the same NASA B-52 that had conducted drop tests and launches of various experimental aircraft, including the X-15. Later, Orbital Sciences Corporation commissioned its own L-1011 carrier aircraft, which they kept at Vandenberg AFB.

FULL DISCLOSURE: I was on the Flight Readiness Review Committee for this launch, so this space anniversary is special to me. And somewhere I have a picture of me in front of Orbital Sciences’ L-1011/Pegasus combination….

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