NASA made contact with one of its missing spacecraft Sunday night, over 22 months after researchers lost communication. The long-lost spacecraft, known as STEREO-B, is one half of NASA’s Solar Terrestrial Relations Observatory mission.
The other half of the mission involves spacecraft STEREO-A. Both probes were launched in October 2006, tasked with studying the sun from different vantage points and reporting back to Earth. The mission was only scheduled to last two years, but the STEREOs have lasted longer than expected. STEREO-A has continued to operate on its mission to study the sun.
After a massive search, contact was reestablished on Aug. 21, 2016 – nearly two years after losing communication on Oct. 1, 2014. NASA’s Deep Space Network, or DSN, established a lock on the STEREO-B downlink carrier at 6:27 p.m.
What happened to STEREO-B? According to NASA, the two STEREOs slowly drifted away from Earth as they orbited the sun, one ahead and one behind our home planet. This gave scientists awesome views of the sun’s far side – allowing us for the first time to see the whole sun at once!
Unfortunately, the same slow drift that gave NASA incredible images also pulled each spacecraft to the other side of the sun from Earth. This lead to a three-month period where communication was impossible due to the sun’s interference.
The STEREO spacecraft were designed with a command loss timer, an automatic reset button that restarts the spacecraft after 72 hours without contact. The hard reset happened as expected, 72 hours and 20 minutes after operators stopped communications with the spacecraft. After the reset, STEREO-B was supposed to power itself back on, but it gave barely a glimmer and faded into darkness.
Finding STEREO-B is just half the battle. Now researchers must conduct a slew of tests to decide if the craft is healthy and fully-functioning. They must assess the spacecraft’s subsystems and instruments to determine if it’s recoverable. Hope to hear from you soon, STEREO-B! 🛰