WASHINGTON — A weather satellite is in good shape after experiencing a problem while 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 November 10 from Vandenberg Space Force Base in California, deploying the satellite into its planned polar orbit. While the agency initially said 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 to confirm the deployment.
In two subsequent updates later that day, NASA said controllers were still working to deploy the network, but provided few details on the specific issue. The spacecraft was “power positive,” meaning it generated power from the part of the undeployed array exposed to the sun, but the agency did not provide further details on why. which the network had not extended.
In an update released about 14 hours after reaching orbit, NASA said the JPSS-2 solar array had finally been deployed. “The operations team will continue to assess a previous solar array deployment issue, but at this time the satellite is healthy and functioning as expected,” NASA said.
Shortly after the update, 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 to provide 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 experience solar array deployment issues 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 insulating blanket on the Antares rocket was lodged in the solar panel deployment mechanism, but the spacecraft still had enough power from the single deployed panel to operate, reach the International Space Station on November 9.
The two spacecraft, however, have very different solar panel systems. The Cygnus uses UltraFlex dies that unfold into a circular shape, like a fan. JPSS-2 uses more traditional rectangular gratings. A NASA statement said the array has four panels, while a Northrop Grumman fact sheet said the network has five panels that collectively produce at least four kilowatts of power.
NASA’s post-launch statement also confirmed the success of a technology demonstration payload launched with JPSS-2 on the Atlas rocket. The Low Earth Orbit Flight Test of Inflatable Decelerator Payload (LOFTID) deployed from the Centaur upper stage 75 minutes after liftoff. Its inflatable heat shield, six meters in diameter, protected the spacecraft during its re-entry over the Pacific Ocean, splashing down 800 kilometers east of Hawaii. A boat recovered both LOFTID and a data logger ejected from the vehicle during its descent.
“We were delighted to work with our fellow scientists at ULA, NASA and NOAA to perform this technology demonstration in conjunction with the launch of JPSS-2,” said Jim Reuter, NASA Associate Administrator for space technology, in the release. NASA said it will share more details about the results of the LOFTID flight experiment after the project team reviews the data.