Lockheed Martin Radiators Launched to International Space Station
DALLAS, TX, October 9th, 2002 -- Three Lockheed Martin Heat Rejection Subsystem (HRS) radiators were launched aboard the Space Shuttle Atlantis Monday as part of the S1 (first starboard) payload, and have arrived at the International Space Station (ISS). The HRS radiators serve as the "air conditioners" for the ISS by rejecting into space the excess heat produced by the equipment and people in the Space Station's pressurized modules.
When completed, the 10 segments of the truss system built by The Boeing Company will eventually span more than 300 feet and house the space station's solar arrays, along with carrying power, data and environmental services throughout the station. The girder-like S1 will be attached to the S0 (starboard zero) truss delivered in April 2002. The P1 (port one) truss will be delivered by space shuttle Endeavour in November 2002 and attached to the opposite side of the S0 truss.
Lockheed Martin Missiles and Fire Control is under contract to The Boeing Company to produce HRS and Photovoltaic Radiator (PVR) panels for ISS. Three PVRs have been functional on the Station for nearly two years, and three additional HRS radiators are scheduled for launch later this year.
"This is a very exciting time for our space program," said Dave Williams, director - Space Programs for Missiles and Fire Control. "It's been several years since we were first contracted to produce the HRS radiators, and we're pleased that they are now poised to be fully functional on the Space Station. We know that the Station is going to provide tremendous benefit to mankind over the next few decades, and it's gratifying to be part of that world-wide effort."
This HRS radiators work in a fashion similar to the way the radiator cools a car engine. Heat within the modules is collected at various points and transferred into fluid (99.9 percent pure liquid ammonia) that enters the radiator through pipes on one side and is distributed to 22 tubes crossing each of 8 panels in a radiator array.
As the fluid flows through each panel, heat is radiated off into space, thus cooling the fluid. The cooler fluid flows out the other side of the radiator and back to ISS, where it cools the astronauts and equipment. This process is repeated continuously to provide the required cooling.
The three HRS radiators on S1 weigh approximately 7,500 pounds, which is almost 30 percent of the payload on the Space Shuttle Atlantis.
Cinches on each HRS restrain the large "brilliant white" Z-93 radiator panels during the ascent to space. Once on-orbit, the S1 payload will be removed from Atlantis's Cargo bay by the new "Canadarm2" robotic arm, and installed on the starboard side of ISS.
The middle of the three HRS radiators will then have its cinches remotely released, and the HRS will be commanded to deploy from its launch configuration of less than three feet to its fully deployed length of 75 feet. This operation is presently scheduled for Sunday, October 13.
The remaining two HRS radiators will be deployed in the near future when the growing complex's demand for heat rejection increases to the final configuration. A similar operation will happen in November, when the second set of three HRS Radiators on P1 will be flown to ISS aboard the Shuttle Endeavour, and another HRS is deployed.
After the November launch of HRS radiators, Lockheed Martin will then have only one final Photovoltaic Radiator remaining to launch. That final PVR is at Kennedy Space Center being prepared for its journey to ISS in 2004.
With participation of 16 countries, the International Space Station is the largest international peacetime scientific program in history. Once complete, the Station will have a length of 360 feet and a width of 290 feet, and will be visible from Earth on a clear day or evening with the naked eye. The average orbit altitude is 220 miles, with an orbital speed of 17,500 mph. The station orbits the Earth 18 times per day. Once complete, the ISS will have 20,000 pounds of Lockheed Martin radiators aboard.
Lockheed Martin Missiles and Fire Control develops, manufactures and integrates world-class air defense, fire support, strike weapon, naval munition, combat vision, anti-armor and advanced product solutions and systems for U.S. and international armed forces. Boeing is NASA's prime contractor for the International Space Station and responsible for design, construction and integrating the components provided by 16 international partners. The company also supports NASA in operation of the ISS. A unit of The Boeing Company, Boeing Integrated Defense Systems is one of the world's largest space and defense businesses.