JPSS-2 deploys solar array after delay

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WASHINGTON — A weather satellite is in good condition after suffering a problem deploying its solar array immediately after launch Nov. 10.

NASA launched the Joint Polar Satellite System (JPSS) 2 spacecraft on a United Launch Alliance Atlas 5 rocket early Nov. 10 from Vandenberg Space Force Base in California, deploying the satellite into its planned polar orbit. While the agency initially stated that the spacecraft extended its single solar array shortly after reaching orbit, the agency said about three hours after liftoff later that telemetry was unable to confirm the deployment.

In two subsequent updates later in the day, NASA said that controllers were still working to deploy the array, but provided few details on the specific problem. The spacecraft was “power positive,” meaning that it was generating power from the part of the undeployed array exposed to the sun, but the agency didn’t provide additional details on why the array had not extended.

In an update issued about 14 hours after reaching orbit, NASA said the JPSS-2 solar array had finally deployed. “The operations team will continue to evaluate an earlier solar array deployment issue, but at this time, the satellite is healthy and operating as expected,” NASA stated.

Shortly after the update, both NASA and Northrop Grumman, the prime contractor for JPSS-2, issued press releases celebrating the successful launch, with no additional information about the solar array issue.

The spacecraft, which will be renamed NOAA-21 when it enters service for the National Oceanic and Atmospheric Administration, will join the first JPSS satellite, NOAA-20, as well as Suomi NPP in providing weather data from polar orbit. JPSS-2 is the first of three such satellites that Northrop Grumman is under contract to produce for launch over the next decade.

JPSS-2 is the second Northrop-built spacecraft to suffer solar array deployment problems this week. The company’s NG-18 Cygnus spacecraft, launched Nov. 7, failed to deploy one of its two solar arrays after reaching orbit. The company later said debris from an insulation blanket on the Antares rocket lodged in the solar array deployment mechanism, but the spacecraft still had enough power from the one deployed array to function, reaching the International Space Station Nov. 9.

The two spacecraft, though, have very different solar array systems. The Cygnus uses UltraFlex arrays that unfold into a circular shape, like a fan. JPSS-2 uses more traditional rectangular arrays. A NASA statement said that the array has four panels, while a Northrop Grumman fact sheet said the array has five panels that collectively produce at least four kilowatts of power.

The post-launch NASA statement also confirmed the success of a technology demonstration payload that launched with JPSS-2 on the Atlas rocket. The Low-Earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) payload deployed from the Centaur upper stage 75 minutes after liftoff. Its inflatable heat shield, six meters across, protected the spacecraft as it reentered over the Pacific Ocean, splashing down 800 kilometers east of Hawaii. A boat recovered both LOFTID and a data recorder ejected from the vehicle during its descent.

“We were pleased to work with our ULA, NASA science and NOAA colleagues to perform this technology demonstration in conjunction with JPSS-2’s launch,” Jim Reuter, NASA associate administrator for space technology, said in the statement. NASA said it would share more details about the outcome of the LOFTID flight experiment after the project team reviews data from it.