GRAHAM WARWICK / WASHINGTON DC
NASA says reusable spaceplane "performed as expected" after structural upgrade
Boeing has completed structural testing of the X-37 reusable spaceplane, after strengthening the structure to overcome a design flaw. NASA says an initial review of the test data "indicates that the vehicle performed as expected".
Proof testing of the X-37 approach and landing test vehicle was conducted at Boeing's Huntingdon Beach, California, plant. After a detailed analysis of the tests, the unmanned vehicle will be returned to its assembly site in Palmdale, California, to be prepared for atmospheric drop tests planned for next year.
The approach and landing test vehicle is one of two X-37s being built by Boeing Phantom Works under a $301 million contract received late last year as a modification of its original 1999 agreement with NASA. An orbital test vehicle is in the early stages of design, and is scheduled for launch in 2006.
The main spar of the carbonfibre-composite wing on the atmospheric-test X-37 had to be modified after a design flaw was uncovered that reduced its calculated strength. The proof tests appear to indicate the wing's design strength has been restored. The vehicle is to be drop tested five times from NASA's Boeing B-52 at altitudes up to 40,000ft (12,000m), beginning late in the third quarter of next year, to demonstrate autonomous descent and landing capability.
The orbital-test X-37 is scheduled for launch on a Boeing Delta IV or Lockheed Martin Atlas V expendable booster in the third quarter of 2006. The unmanned vehicle will remain in orbit for two to three days before re-entering and landing, although NASA is reportedly talking to Boeing about designing into the X-37 the capability to stay in orbit for up to nine months.
The baseline programme is intended to demonstrate thermal protection systems, high-temperature structures and autonomous guidance, navigation and control. Extended on-orbit endurance would allow NASA to test systems for automatic rendezvous with the International Space Station, as well as using the X-37 as a reusable testbed for satellite and spacecraft technologies.
Source: Flight International
