The landing of NASAs Endurance Mars Rover next month will create severe waves, some of which may help scientists better understand the structure of the red planet.
Endurance, the centerpiece of NASA’s $ 2.7 billion. Life-hunting, test-caching Mars 2020 mission, is scheduled to stir inside the 28-kilometer (45 km) Jezero Crater on February 18th. The epic landing will generate seismic signals that one of the rover’s cousins, NASAs InSight Mars lands, will attempt to detect more than 3,200 kilometers away, reports a new study.
If that happens, it will first be a spaceflight: No spacecraft has ever “heard”
In photos: NASA’s Mars Perseverance Rover mission to the red planet
InSight’s hypersensitive seismometer package has been taken up hundreds of earthquakes since the lander touched down in November 2018 on a Mars plain known as the Elysium Planitia. InSight team members use these measurements to map the interior of the red planet in unprecedented detail, the main goal of the mission.
However, such interpretive work can be difficult.
“Unlike on Earth, where you can independently find out when and where one [seismic] source happened, and of course how big it was March, we have a single station and we are both trying to identify the mechanics of the source and structure of the planet through which the waves spread, “studies lead author and InSight team member Ben Fernando, a PhD student at the University of Oxford in England, told Space.com.
“Removing these two from each other is not necessarily trivial,” he added. “In the simplest explanation, if you were in a room and could not see, it’s hard to see if someone was talking loudly far away or quiet close to you. And besides, if you did not know what the shape of the room was, it would be even harder. “
The landing of endurance therefore represents a great opportunity for InSight scientists – a chance to collect seismic data generated by an impact whose details are known in advance, Fernando and his colleagues wrote in the new study.
A decent chance
March 2020 will apply the same approach to entry, descent and landing (EDL) as its predecessor, the Curiosity Mars Rover, down safely in August 2012.
March 2020 hits the thin Mars’ atmosphere hard, be braked significantly by friction and then insert a supersonic parachute to brake further. About seven minutes after atmospheric entry, a rocket-powered sky crane will gently lower endurance to the floor of Jezero on cables and then fly off to deliberately land down a safe distance.
The last step does not generate seismic waves of appreciable strength. But two other points during the EDL sequence are likely to produce relatively strong signals, according to Fernando and his team.
Such a signal will be generated by a sound barrier that will occur when Mars 2020 comes within approximately 100 miles (100 km) of Mars’ surface, an altitude at which the atmosphere is close enough “for significant compression to occur”. the researchers wrote in the new study.
Some of the energy from this boom – which will peter out when the spacecraft goes under sound, about three minutes before the touchdown – will hit the surface of Mars and transform into seismic waves. But this signal will not be strong enough to be picked up by InSight, which sits about 3,145 miles (3,452 km) from Perseverance’s landing site, Fernando and his team calculated, citing the scattering effect of Martian winds as a key factor.
The second signal comes via an actual impact on the surface – actually two impacts. Shortly after Mars 2020 hits the atmosphere, the spacecraft replaces two “Cruise Mass Balance Devices” (CMBDs) to change its mass center. The CMBDs, each weighing 170 kg. (77 kg), will be dropped from very high up at an altitude of about 1,450 km and will hit the ground at an estimated speed of 8,700 mph (14,000 km / h), Fernando said.
Mars InSight in Photos: NASA’s mission to study the Mars core
It is unclear how strong the seismic waves from the CMBD impacts will be; InSight has not yet registered any confirmed impacts on Mars, so predictions are difficult. But Fernando and his team generated estimates based on data collected here on Earth and beyond the moon, and these numbers suggest that InSight has a decent chance of measuring the waves.
“In realistic best cases (and assuming identical weather and noise spectra for the same period a martian year earlier), the required signal-to-noise ratio would be sufficient for a positive detection 40% of the time,” the researchers wrote in the new study, which has been submitted to (but not yet accepted by) the journal Earth and Space Sciences. You can read a free pre-print of it here.
There’s some luck involved in this relatively rosy figure: The CMBD-generated waves arrive at InSight’s location early in the evening, Elysium Planitia time, the quietest part of the day, Fernando said.
A detection would be a pretty big deal for InSight team members. They wanted to know exactly how far and how fast the seismic waves traveled.
“If you know how fast they went, you can start figuring out what the structures they spread through were,” Fernando said.
Endurance, by the way, will aim to document its own landing in an unprecedented way. March 2020 carries two microphones, one of which will try to capture the dramatic sounds of the EDL on February 18th. (The other is part of Perseverance’s rock-zapping SuperCam system.) No Mars spacecraft has ever detected the raw sounds of the red planet before.
Endurance is not the only spacecraft planned to land on Mars this year. China The Tianwen-1 mission arrives in orbit on February 10th and drop a lander and rover on the red planet about two months later if all goes according to plan.
The InSight team would love to listen to the Tianwen-1 landing, Fernando said. But details about the mission – specifically its exact landing time and location – are difficult to obtain, so “it is not possible to predict the detectability of this signal” at the moment, the researchers wrote in the newspaper.
The Euro-Russian ExoMars program launches one lander-rover duo to Mars in 2022. InSight will almost certainly not be able to detect seismic signals from that landing sequence, given that the ExoMars duo will be moving down the other side of the planet from InSight, Fernando said.
SpaceX aims to soon fly its next generation Starship spacecraft to Mars – perhaps as early as 2024, company founder and CEO Elon Musk has said. If InSight lives long enough, it could possibly document the touchdown of one or more of these 165-foot (50-meter) stainless steel spacecraft.
“It’s not out of the question,” Fernando said. “It just depends on where they decide to land.”
Mike Wall is the author of “Out there“(Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.