Will Monitor Heat Shield Tiles For Launch Impacts, Transition Experiment

Researchers at NASA's Langley Research Center will be back on the job watching over the space shuttle Discovery during its last mission, scheduled Feb. 24 to March 7. Some are part of the impact assessment and aerothermodynamic heating teams, and others will be watching during the orbiter's return to Earth.

Discovery's STS-133 mission is set to launch shortly before five in the afternoon, Thursday, Feb. 24, and return 11 days later. The shuttle is rocketing to the International Space Station to deliver a multi-purpose module and spare parts and storage capacity to the orbiting complex. Discovery also will transport Robonaut 2 – the first humanoid robot in space. During the mission NASA Langley researchers participate on damage assessment and impact dynamics team. Those teams identify and evaluate if there's any risk to the shuttle if the orbiter's wing leading edges, nosecone and fragile tiles get hit from debris.

Engineers also play a lead role in managing the Boundary Layer Transition Experiment, which records temperature changes from a small "speed bump" installed on Discovery's lower left wing. The idea of the bump, which is about the size of a piece of gap filler that might shake loose in flight, is to "trip the boundary layer" or disrupt airflow across the shuttle's belly, turning it from smooth to turbulent. Turbulence creates extra heat. How much heat is something engineers need to know to design safe spacecraft.

Discovery Fuselage And Fuel Tank On Launch

Another group from Langley, the Hypersonic Thermodynamic Infrared Measurements or HYTHIRM team, is keeping an eye specifically on the heat of the shuttle's re-entry into Earth's atmosphere. They're working to improve computer models and designs for future spacecraft thermal protection systems. "We're hoping to successfully capture thermal images of the shuttle for the sixth time," said aerospace engineer and principal investigator Tom Horvath in the Aerothermodynamics Branch at Langley. "We plan to once again place a Navy aircraft under the shuttle flying 18 times faster than a bullet so the crew can use a special infrared optical system to record Discovery's heat signature during re-entry."

The HYTHIRM team has been successful in acquiring thermal images of re-entry during previous shuttle missions including STS-119, STS-125, STS-128, STS-131 and STS-132. So far they have captured calibrated thermal imagery ranging from Mach 8.5 to Mach 15.5.

Discovery On Landing

The US Navy NP-3D Orion aircraft and the long-range infrared optical system are called "Cast Glance" and are operated by the NAVAIR Weapons Division, Pt. Mugu, CA. The Orion, which can stay aloft for about 11 hours, stays over international waters until it's time for the shuttle to re-enter. At closest approach, the aircraft and its crew will be approximately 25-40 miles from the shuttle. Because the orbiter is banking on descent the plane will not be directly under it. Mission planners say the aircraft location and flight maneuvers proposed for the observation have been carefully planned to ensure safety to the orbiter and the respective crews.

A team from NASA Langley will be in mission control during re-entry to collect the most up-to-date shuttle re-entry information and make recommendations to the P-3 flight crew regarding adjustments to the camera settings and aircraft position for optimal viewing. The data will be recorded and downloaded post-mission once the P-3 Orion returns to its base of operations.

In a first for the HYTHIRM team, infrared optical systems on the ground will simultaneously join the aircraft in snapping thermal pictures. Crews using technology called the Mobile Aerospace Reconnaissance System will also try to capture an image of Discovery as it returns to Earth. They will be stationed on the west coast of Florida to capture infrared measurements after the shuttle has slowed down to approximately six times the speed of sound.

The HYTHIRM team plans to take a thermal snapshot of the space shuttle Endeavour, which is scheduled to launch for the last time April 19. It is also working with other military and DOD and commercial space organizations to expand capability and to apply imaging technologies to other hypersonic flight test programs.

FMI: www.nasa.gov/langley