SAN FRANCISCO — When NASA’s Glory climate-monitoring spacecraft plunged into the Pacific Ocean due to launch failure in March 2011, scientists were concerned they would have no way to prevent a lengthy gap in their observations of solar energy, the primary driver of Earth’s climate. Glory’s Total Irradiance Monitor instrument was designed to measure solar energy reaching Earth and extend a record of solar energy data spanning more than 30 years.
“When we lost the Glory mission, it sent a chill down everybody’s spine because we thought there was going to have an imminent gap in that data record,” said Jeff Privette of the U.S. National Oceanic and Atmospheric Administration (NOAA) National Climatic Data Center in Asheville, N.C.
Those concerns were put to rest Nov. 19 when the Total solar irradiance Calibration Transfer Experiment (TCTE), an instrument designed to measure solar light in all wavelengths, traveled into orbit as one of six payloads on the U.S. Air Force Space Test Program 3 satellite that launched along with 28 secondary payloads on an Orbital Sciences Corp. Minotaur 1 rocket that lifted off from NASA Wallops Flight Facility in Virginia.
“TCTE plays a critical role in extending the total solar irradiance record,” Privette said.
Since 2003, NOAA has obtained data on the sun’s energy from the Solar Radiation and Climate Experiment mission. The NASA-sponsored, Orbital Sciences-built spacecraft, designed to gather data for five years, began to show signs of its advanced age including battery degradation in 2011, Privette said.
In early 2012, the University of Colorado’s Laboratory for Atmospheric and Space Physics informed NOAA that it had a solar sensor that was scheduled originally to fly on a NASA space shuttle mission but was never used. Within weeks, U.S. Air Force officials approached NASA and NOAA to say that an instrument scheduled to fly on the Space Test Program Satellite 3 would not be ready in time so the service had room for an additional payload. “From that serendipitous moment in 2012, less than two years ago, we went from not having any way to carry this solar record forward to having something in space,” Privette said.