February 18 2019
Katy recently accepted a communications position with the Satellite Servicing Projects Division (SSPD) of the NASA Goddard Space Flight Center. This past weekend I had the opportunity to visit her new place of employment. While there, a co-worker of my sister was kind enough to give us a private tour of the current happenings in their small corner of NASA.
What my sis failed to mention to me previously is that her division was working on a mission to refuel the infamous, Y2K defying Landsat 7 satellite! Landsat is a household name for most anyone that works in the geography/remote sensing realm. I probably spent half my undergrad career acquiring, stitching, and analyzing Landsat 5/7 imagery. Understandably when I walked into the vault and was greeted by a full sized replica of the bird I sort of geeked out.
What I came to learn during the tour is that current protocol for satellite end of life procedures is to reserve enough fuel to push the object into a graveyard orbit. Of course nobody is regulating this so what generally ends up happening is old satellites either become space junk and pollute low earth orbit, or they re-enter the atmosphere and burn up. The one constant of the two aforementioned strategies is that nothing is recycled. The goal of the SSPD is to kick this wasteful trend and begin designing the next wave of satellites which will take post-orbit contact into account.
The Landsat 7, which launched in 1999, is near EOL. It’s mission is superfluous with the addition of Landsat 8 and the soon-to-launch Landsat 9. Additionally it was never designed to be serviced. Given these constraints, the SSPD determined it would be a great candidate to test their newly developed tools. The plan, as it was explained to us, is to approach and capture the 7 autonomously using machine vision and a robotic gripper. From there, a custom developed arm with seven degrees of freedom will perform the necessary meanuvers to expose the fuel ports, and begin restocking. Unlike the capture portion of this mission, the arm will be piloted by an operator on the ground. Barring any unforeseen circumstances, like say a government shutting down, the mission is expected to launch in 2022.
Full size replica of the Landsat 7
Satellite capture test equipment
Robotic servicing arm