GREEN BANK, W.Va. – The National Science Foundation’s Green Bank Telescope (GBT) will play a role in the upcoming mission of NASA’s Mars 2020 Perseverance rover. The GBT will receive communications from the rover as it arrives on Mars on February 18 and pass these on to NASA’s Jet Propulsion Laboratory (JPL) in southern California.
The GBT will track the faint communication signal transmitted by Perseverance at a frequency of just over 400 MHz. As the rover enters the Martian atmosphere the total descent, known as the Entry-Descent-Landing phase (EDL), will take about seven minutes. Referred to as the “seven minutes of terror,” Perseverance must slow down from 12,000 miles-per-hour to just a few feet per second. This rapid change in speed generates a lot of heat, creating a shield of ionized particles around the rover, temporarily obscuring its communication signal to Earth. To reach to surface safely, Perseverance uses a heat shield to protect itself during entry, deploys a supersonic parachute to slow down, and executes the “skycrane” maneuver to slowly touch the rover down on its wheels.
Will Armentrout, Green Bank Observatory project scientist for Perseverance, recalls, “I remember exactly where I was when NASA landed Curiosity on Mars in 2012, curled up at home with a bag of popcorn and getting ready to start as a physics graduate student the next week. For the 2018 Insight landing, I was a post doc at Green Bank peeking over the shoulder of another scientist. There’s such a human component to all of these NASA missions, and they have a way of sticking in our memory.” When asked what he will be doing for the 2021 Perseverance landing, Armentrout replied, “Supporting the GBT controls, praying we see that signal.”
Since it will take nearly 12 minutes for signals to get from Mars to Earth, Perseverance will have already landed before the GBT receives the signal that the rover has entered the Martian atmosphere. The Effelsberg telescope in Germany will also be monitoring Perseverance as it lands on Mars.
Green Bank Observatory scientist Toney Minter carefully manages the GBT’s dynamic scheduling system to make time for these lander observations. “The GBT is in demand – each year we receive three times more requests than we are able to schedule from scientists around the world for observing time.”
As NASA/JPL has shared, while on Mars the Perseverance rover will collect carefully selected and documented rock and sediment samples for future return to Earth, search for signs of ancient microbial life, characterize the planet’s geology and climate, and pave the way for human exploration beyond the Moon.
This is not the first time that the Green Bank Telescope has supported a NASA mission to Mars. In 2018, the GBT received direct signals from the Mars InSight Lander. This provided backup information to NASA during the critical landing stages of the spacecraft and confirmed its successful descent. The GBT was also used to support the Phoenix landing in 2008.
Science Center manager Amanda White coordinated a live stream of the NASA and GBT control rooms during the 2018 landing, viewed on site in Green Bank and at the Clay Center for the Arts and Sciences in Charleston, West Virginia. Says Amanda, “Visitors were very excited to witness this historic science, and to learn that West Virginia plays an important role in these NASA projects. We’re excited to be a part of this again in 2021, and to share even more educational resources with the public.”
The Green Bank Observatory Science Center and the Clay Center for the Arts and Sciences will be offering STEM education programs from late January through mid-February, when the lander will touch down on February 18th. The Clay Center will be sharing in-person programs on Saturdays during their public hours at 10:00 AM – 12:30 p.m. and 1:30 – 4:00 p.m., along with activities and videos through their social media. Visit theclaycenter.org to make your reservation. The Green Bank Observatory will be sharing activities, videos, and livestreams through our website and social media.