STS-123 launches Endeavour with couple of minor problems

William Atkins
Tuesday, 11 March 2008 19:49

Science - Space

On Tuesday, March 11, 2008, NASA's space shuttle Endeavour was launched from the Kennedy Space Center at 2:28:14 a.m. EDT, with two problems, one to its steering thrusters and another to a system that dissipates heat.      

The launch began a sixteen-day mission to install the Japanese Kibo and the Canadian Dextre onto the International Space Station (ISS) in orbit about the Earth.

Marcia Dunn, Associated Press writer, called the night blast off: “… a flash of light, giving a peach-yellow glow to the low clouds just offshore before disappearing into the darkness.” [AP: “Space Shuttle Endeavour Blasts Off”]

However, a couple of problems occurred on the early phase of the flight, which turned out to be only minor in severity.

Technical problems occurred with a part on the flash evaporator system (FES) and with two left reaction control system (RCS) thrusters.

The FES is activated about 125 seconds into the flight. It is used to remove heat with the use of boiling water through Freon-21 coolant loops. During orbital operations, the FES is used only if the shuttle exceeds its heat capacity.

Under normal orbital operations, the shuttle’s payload bay doors are open all of the time and special radiator panels are exposed to space in order to dissipate heat. The FES is activated only if the radiator panels can't remove heat fast enough to keep the orbiter cool. Many times, if the shuttle is very high in its orbit, more heat impinges on the orbiter, causing the FES to be activated.

The FES system is activated again during de-orbit and reentry operations, after the payload bay doors are closed. The system is closed down at about 100,000 feet from the surface of the Earth, when another coolant system is activated for the rest of the flight to landing.

To correct the problem the astronauts turned on the back-up FES when the primary one failed.

The reaction control system (RCS) comprises the forward and aft RCS. The forward RCS is located in the forward fuselage nose area and the aft (right and left) RCS is located near the orbital maneuvering system (OMS) within the OMS/RCS pods at the rear of the orbiter.

The RCS jets are used to provide thrust while in space for small velocity change maneuvers called attitude (rotational) maneuvers, and sometimes called pitch, yaw, and roll maneuvers.

The thruster problem to the two left RCS jets ended up being a defective electronics card.

The main job of the STS-123 crew is to perform five spacewalks--a record number for shuttle missions. Please read on for additional information on these spacewalks.