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The X-33 was scheduled to complete its first flight by March of 1999. As of early 1999 the projected date for the X-33 rollout was May 1999, with its first flight planned for that July. The program is scheduled to be completed by the year 2000. The baseline test program would include a combined total of approximately 15 flights beginning in July 1999 and concluding in December 1999. The baseline test flight plan includes three short-range, seven mid-range, and five long-range test flights. Actual numbers of test flights to any range may vary due to changing plans and/or actual test flight data evaluation.
Test flights involve: (1) launching the X-33 from a vertical position like a conventional space launch vehicle閠his reduces the weight of the landing gear and wheels to only that required to support an unfueled vehicle (baseline dry weight of vehicle is approximately 29,500 kg (65,000 lb) and fueled weight of X-33 is approximately 123,800 kg (273,000 lb)); (2) accelerating the vehicle to top speeds of Mach 15 (15 times the speed of sound or approximately 18,000 km/hr (11,000 mph) and reaching high altitudes up to approximately 75,800 m (250,000 ft); (3) shutting down the engines; gliding over long distances up to 1,530 km (950 mi) downrange of the launch site followed by conducting terminal area energy maneuvers to reduce speed and altitude; and (4) landing like a conventional airplane.
Optimally, the flight test plan to meet Program objectives would involve flights of approximately 160, 720, or 1,530 km (100, 450, and 950 mi). Landing sites meeting the above criteria and providing 3,050 m (10,000 ft) of hard surface are referred to as short-, mid-, and long-range landing sites, respectively. The X-33 Program prefers to land the vehicle on a dry lake bed at least for its first flight in order to have a wider and slightly safer landing area than conventional runways offer. The same philosophy was used for the Orbiter's and most X-planes' first landings.
The launch site is located within Edwards Air Force Base, California. A total of fifteen launches are scheduled over a period of approximately one year. The X-33 will blast off from the site near Haystack Butte, located at the eastern edge of the Base near the AFRL/PR. Predominantly local NASA and USAF tracking and command assets will be utilized to support this phase of flight. Construction of the X-33 launch site at was completed in December 1998, just a little more than 12 months after groundbreaking.
Once the X-33 is readied for flight, the engines will be fired two times on the launch pad, with the second firing having a duration of 20 seconds. The longest flight will be approximately 20 minutes at an altitude of about 55 miles. The plan is to demonstrate a 2-day turnaround for the vehicle. Landing sites include Silurian Dry Lake Bed, Michael Army Air Field and Malmstrom Air Force Base. One of NASA's 747s will be used to carry the X-33 from its landing destinations back to Edwards.
Silurian Dry Lake Bed near Baker, California is approximately 3000 feet wide and 12000 feet long. The lake bed will be the site of the first landing attempts for the X-33 vehicle. Three flights are scheduled to Silurian Lake that will include vehicle speeds in excess of Mach 3. The flights are scheduled to start in mid 1999.
Michael Army Airfield will be the second landing site for the X-33. This will also be the first downrange runway landing. Michael Army Airfield is part of the Utah Test and Training Range, located south of Salt Lake City. This airfield is located on the eastern boundary of Dugway. The airfield has a 3,960 m (13,000 ft) long by 61 m (200 ft) wide hard surfaced runway. Immediate surrounding terrain is relatively flat. It is a secure facility with a long history of flight operations. The airspace above Dugway Proving Ground is restricted military airspace controlled by Hill Air Force Base which manages and approves use of the Utah Test and Training Range (UTTR). Seven flights are scheduled to Michael with vehicle speeds in excess of Mach 10. Flights are scheduled to start in the latter part of 1999.
Malmstrom Air Force Base will be the third and final landing site for the X-33. The airfield was closed on Decmeber 31, 1996, except for the area used by helicopters of the Malmstrom's Air Rescue Flight. The airfield has a hard surface runway approximately 3,500 m (11,500 ft) long and 61 m (200 ft) wide with a 305 m (1,000 ft) overrun at each end. Since closure of the airfield, the USAF has no plans or budget to operate the runway. Five flights are scheduled to the Malmstrom runway with vehicle speeds in excess of Mach 15. Flights are scheduled to start in the spring of 2000. |
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發表於 07-5-19 09:58:20
