STSat-2B, orScience and Technology Satellite-2B, was a South Koreansatellite which was lost in the failure of the second flight of theNaro-1launch vehicle. It was to have been operated by theKorea Aerospace Research Institute (KARI), and was intended to demonstratetechnology for future spacecraft. The satellite had a mass of 100 kg (220 lb),^[2] and was expected to operate for at least two years.^[1]

STSat-2B was originally intended to operate alongside a second spacecraft,STSat-2A; however STSat-2A was lost in 2009 after the payload fairing of its carrier rocket failed to separate, leaving the rocket unable to achieve orbit.^[4]

The primary instrument aboard STSat-2B was theDual-channel Radiometer for Earth and Atmosphere Monitoring, or DREAM, which would have measured thebrightness temperature of theEarth at 23.8GHz and 37 GHz.^[5] The secondary payload, the Laser Retroreflector Array (LRA) was to have been used for theSatellite laser ranging experiment, which was intended to determine the parameters of the satellite's orbit with a greater degree of precision. Data collected by the secondary payload would have been used to calibrate DREAM, to conductgeodetic research, and to evaluate the performance of the launch vehicle.^[1] Due to lower manufacturing tolerance, the retroreflectors on STSat-2B would have provided greater precision than those intended on STSat-2A.^[6]

A series of technological experiments were also to have been conducted; investigatingattitude control systems, and testingpulsed plasma thrusters,star trackers, aSun sensor, as well as an experimental onboard computer, and data relay at rates of up to 10megabits per second.^[1]

STSat-2B was launched by a Naro-1 launch vehicle, flying from theNaro Space Center. The launch was the second flight of the Naro-1, which consisted of a modifiedAngara first stage manufactured byKhrunichev,^[7] and a South Koreansolid-fuelled upper stage. The previous Naro-1 launch was that of STSat-2A, which occurred in August 2009 and ended in failure.^[4]

The launch was initially scheduled to occur on 9 June 2010, during a two-hourlaunch window opening at 07:30UTC (16:30 local time). Further launch attempts were available at the same time each day until 19 June 2010.^[8] The launch attempt on 9 June 2010 was scrubbed after the launch pad's fire suppression system activated for no apparent reason.

Following the scrub, the launch was rescheduled for the next day, and took place at 08:01 UTC (17:01 local time) on 10 June 2010.^[3] During the first stage burn, around 137 seconds into the flight, contact with the rocket was lost.^[9] South Korean science ministerAhn Byung-man later told reporters that the rocket was believed to have exploded.^[10] If the launch had been successful, STSat-2B would have been deployed into an orbit with aperigee of 300 km (190 mi), anapogee of 1,500 km (930 mi), and around 80.0° ofinclination.^[2]

Wikinews has related news:

• South Korean Naro-1 space rocket explodes after take-off

• Satellites of South Korea
• Spacecraft launched in 2010
• Satellite launch failures
• Earth observation satellites

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