Space Launch Initiative's flight mechanics project begins wo

by Marshall Flight Center

NASA's Marshall Space Flight Center in Huntsville, Ala., in conjunction with Universal Space Lines LLC of Newport Beach, Calif., have created a software tool called Integrated Development and Operations System (IDOS) to enhance flight mechanics technologies for second generation reusable launch vehicles. Flight Mechanics includes the guidance, navigation and control operations on the space vehicle.

IDOS provides a software development environment to design, develop, test and validate the "brains" of the vehicle - the guidance, navigation and control algorithms. These algorithms - a sequence of steps designed for programming a computer to solve a problem - are being developed by Ohio University in Athens. Once tested and validated, the algorithms will be loaded on board the reusable launch vehicle flight computer.

The algorithms will enable the vehicle flight computer to determine, in real time, variables such as actual trajectory, acceleration, attitude, attitude rate, accurate position and velocity. The vehicle flight computer can then determine the best flight path for the vehicle. If the vehicle system detects a significant problem that would affect its flying qualities, it can engage other systems on the vehicle - such as propulsion - to keep the vehicle on a safe course to its planned destination or an alternative landing site.

Advancing guidance, navigation and control capabilities within the vehicle will allow for more automatic vehicle processes and thereby increase safety and reliability for second generation reusable launch vehicles. In addition, this advancement will speed up calculations and mission development analysis, reducing time involved and operating costs.

COBRA engine completes milestones; on track toward prototype

Taking one step closer to a second generation reusable engine, NASA's Marshall Space Flight Center in Huntsville, Ala., and Pratt & Whitney-Aerojet Propulsion Associates recently completed two major milestones for the Space Launch Initiative: a subscale preburner test and a fabrication and proof test of a subscale milled channel wall nozzle for the COBRA engine.

COBRA, short for Co-Optimized Booster for Reusable Applications, is a reusable, hydrogen-fueled liquid booster and second stage engine with a thrust level of 600,000 pounds of force developed by Pratt & Whitney of West Palm Beach, Fla., and Aerojet of Sacramento, Calif.

Aerojet successfully completed testing the first of three subscale preburners for the COBRA engine. Preburners are used to start the engine by burning a fuel and oxidizer to provide power. The COBRA engine will feature a liquid fuel and oxidizer preburner unlike the traditional gas fuel and oxidizer to help lower temperatures and smooth ignition of the rocket engine.

Pratt & Whitney-Aerojet Propulsion Associates completed fabricating and proof testing of an approximately 40 percent scale, milled channel wall nozzle for the COBRA engine. The nozzle is the component connected to the thrust chamber that converts energy produced by hot gases of the ignited fuel and oxidizer into velocity for ascent. The nozzle, capable of withstanding extreme temperatures and pressures, was structurally tested at pressures up to four times higher than normal operation. The tests assist in validating the nozzle design, which will improve safety, cost and reliability while reducing traditional fabrication time from four years to one year.

For more information, please contact June Malone at the Marshall Media Relations Department at (256) 544-0034 or by e-mail at june.malone@msfc.nasa.gov

For additional news and information on the Space Launch Initiative, please see these recent news releases:

* KSC tests smart umbilical mating system for NASA's Space Launch initiative, 4/23/02; available at

http://www-pao.ksc.nasa.gov/kscpao/release/2002/35-02.htm

* Milestone review brings NASA one step closer to new launch vehicle, 4/30/02; available at

http://www1.msfc.nasa.gov/NEWSROOM/news/releases/2002/02-108.html