WASHINGTON — After weather and equipment delays earlier in the week, NASA’s Soil Moisture Active Passive (SMAP) successfully launched Jan. 31 aboard one of the last remaining United Launch Alliance Delta 2 rockets.

SMAP launched at 9:22 a.m. from California’s Vandenberg Air Force Base and separated from Delta 2’s upper stage about an hour after liftoff. NASA began picking up transmissions from SMAP through its Tracking and Data Relay Satellite network shortly after separation.

SMAP_Deploy
SMAP, seen in the background deploying its solar arrays, separated from the upper stage of Delta 2 at 10:18 a.m. Eastern time, about an hour after launch. Credit: NASA TV frame capture.

Previous launch attempts the week of Jan. 26 were scrubbed because of high-altitude winds, and a minor issue with the rocket, which needed repairs to core-stage insulation that keeps its cryogenic oxidizer from boiling off.

SMAP will operate from a 685 kilometer near-polar sun-synchronous orbit to observe the moisture level of soil around the globe to a depth of five centimeters over a three-year primary mission. SMAP cost about $915 million to build, launch and operate, according to NASA’s launch-day press kit.

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Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.