PAUL LEWIS /WASHINGTON DC
Vehicle set to be joined by second demonstrator ready to begin Block 2 multi-vehicle testing in mid-2003
The Boeing X-45A unmanned combat air vehicle (UCAV) is poised to resume flying and will be joined shortly by a second demonstrator in preparation for the start of Block 2 multi-vehicle testing.
The US Air Force is defining an initial capability for the first operational A-45 Spiral 2 version, due to enter service in 2008.
The X-45A has been grounded since June for a planned software update. With just two flights completed and no more than 1h flight time, the remaining Block 1 test programme is intended to "clear the flight envelope to complete the remainder of the demonstration through to Block 4", says Jim Martin, Boeing director X-45 system test. This will cover nine or 10 more flights each lasting 60-90minand include exercising the basic communications, including the vehicle and operator interfaces, guidance and control.
The second X-45A Spiral 0 demonstrator is in the final stages of vehicle-ground control system testing and is due to fly by November, but has no Block 1 objectives.
It will instead clear the way to begin Block 2 multi-vehicle testing starting in mid-2003, which will include beyond line-of-sight UHF and satellite communications and relaying messages between X-45s. The two UCAVs will also conduct co-ordinated taxiing and flying.
A modified Lockheed T-33 will be used to validate guidance and control software before the first Block 2 vehicle flies. From late next year it will begin supporting the Block 3 programme, which will include dynamic mission replanning on the ground and in the air, increasingly complex station keeping and finally a "peacekeeper demonstration" simulating an onboard sensor and the dropping of an inert weapon.
Block 4 will run for nine months to the end of 2004 and focus on the gradual transfer of decision-making capability from the ground to the air, including en route and attack planning, and target selection, culminating in a bomb release. The software incrementally developed on the X-45A will used to support the two larger Spiral 1 X-45Bs planned to fly in 2005.
The USAF aims to minimise major changes between the X-45B and A-45, although the latter will have a wet wing, and a missionised sensor and weapons capability. The air force is asking for an initial Spiral 2 capability to attack and strike enemy defences electronically. "We're probably looking at one vehicle capable of doing both," says Lt Col Earl Whyte, DARPA UCAV programme manager.
Source: Flight International
