Astronomy events are few and far between these days as clubs cope with stay-at-home restrictions and institutional closures in response to the coronavirus pandemic. Most meetings and public star parties have been canceled for March and April while a few wait to see how events unfold.
Like some in arts and entertainment, astronomy clubs are looking for ways to take at least some of their activities online. Case in point, the Seattle Astronomical Society last week held its monthly meeting using the Zoom videoconferencing platform. Members enjoyed a presentation by SAS president John McLaren, who also is a NASA Solar System Ambassador, about the upcoming Perseverance mission to Mars.
A history of Mars exploration
McLaren gave a quick history of Mars exploration, from Mariner 4 which sent 21 photos back from Mars after a fly by in 1965 to the present work of Curiosity. He noted that Viking 1 in 1976 sent back the first photo from the surface of Mars. It was no accident that it shot its own foot.
“If we can only get one picture back, this is the most important picture, because they want to see how well the landing gear performed,” McLaren explained. “If they can see how the landing gear did, it gives them an idea of how they can improve the next lander.”
Unfortunately, experiments conducted by Viking were thought to rule out the possibility of life on Mars, though McLaren noted that there’s still some discussion about whether those experiments were conducted and interpreted properly. In any event, the zeal for Mars exploration cooled somewhat until the mid-1990s, when a Mars meteor discovered on Earth was found to contain what could be fossilized bacteria. This sparked new scientific interest in the Red Planet.
We returned to the surface of Mars in 1997 with Sojourner and Pathfinder, which proved we could land and drive around a rover on Mars.
“It truly was the Pathfinder that led us to design more sophisticated vehicles,” McLaren said. Spirit and Opportunity followed in 2004 and Curiosity landed in 2012.
Same car, new features
Perseverance, known as Mars 2020 until a recently concluded naming contest, will be something of a souped-up version of Curiosity. It’s based on the same design, but they’ve re-engineered the wheels, as those on Curiosity showed heavy wear unexpectedly early in its mission. Perseverance will also carry different instruments more specialized for astrobiology and geology. It will drill core samples and leave them cached on Mars awaiting a possible future return mission. And its cameras in general are more powerful and versatile than those of Curiosity. It’s mission is different, too. While Spirit and Opportunity were sent to follow the water and Curiosity is trying to figure out if Mars could have supported microbial life, Perseverance will actually be looking for evidence of that life.
A big challenge for the engineers will be delivering Perseverance to its landing site, which is in a crater called Jezero on the edge of what appears to have once been a lowland sea. There’s what looks like a former river delta on the edge of Jezero crater.
“The hope is that water was here for a long time, water flowed down here building this silt, that this is the most likely location where they hope to find any signs of life,” McLaren said.
A small target
The challenge is that the landing ellipse, the target they need to hit, is ten times smaller by area than that of Curiosity and some 300 times smaller than Pathfinder’s. They’ll used a technologically enhanced version of the sky crane technique that worked for Curiosity to try to hit that target.
The window for a possible launch opens on July 17 this year and McLaren said NASA expects to land Perseverance on Mars on February 18, 2021.
You can watch a recording of McLaren’s presentation on the Seattle Astronomical Society website.
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