Boeing has unveiled the Heavy Lift Variant (HLV) of their Delta 4 booster, part of the Air Forces Evolved Expendable Launch Vehicle (EELV) program. This new booster will give the United States Air Force the ability to launch heavy payloads (up to 29,595 pounds)  into geosynchronous-transfer orbit, compared to 9,255 pounds from the Delta 4 medium version. The data gathered on a December 10 test flight will be used when a Delta 4 HLV carries a Defense Support Program missile-warning satellite (used for detecting ballistic missile launches) into orbit in September 2005.

The Delta 4 HLV will have the highest payload capability of any rocket currently in the Air Force inventory. The Delta 4 HLV will be a vital addition to the Air Force, since the Space Shuttle is being restricted for the International Space Station. The Shuttle had been seen as an option to refuel or replace spy satellites like the KH-11, Advanced KH-11, KH-12, and Lacrosse. The loss of the Challenger on liftoff in 1986 impeded past satellite operations (only one KH-11 was put into orbit in 1987). Now, the Air Force will not have all of its eggs in the basket of the Space Shuttle. The ability to put a large payload into orbit means that now, spy satellites will be able to carry a larger fuel load. This means the satellite has a longer life (meaning fewer have to be launched, saving money in the long run) and more ability to maneuver (thus making them harder to kill and also becoming more responsive in a crisis they can shift their orbit).

Boeing is hoping that commercial markets for the Delta 4 HLV will emerge. NASAs missions to the moon and Mars are the only likely non-Air Force mission as of now, but Boeing hopes that successful launches for the Air Force will also interest commercial launches. Harold C. Hutchison ([email protected])