Perseverance at Mars

NASA’s Perseverance rover and its tagalong helicopter, Ingenuity, have been on Mars for a little more than one Earth year now. During that time, the rover has driven nearly 5 kilometers (3 miles) through Jezero Crater, doubling back on a V-shaped path. Its route took it along the boundary of two sections of the crater floor: Séítah, an older formation with rocks rich in olivine grains, and Máaz, a slightly younger, olivine-free formation that has rounded, spilled-pudding-like edges (the technical term for that is lobate).

The rover has scraped off six rocks, revealing complex, grainy textures beneath the worn surfaces. Samples stowed from these sites — six cores of rock and one (by mistake) of nothing but Martian air — will someday be brought back to Earth for detailed analysis.

Observations of these and other rocks along Perseverance’s path indicate that both Séítah and Máaz are igneous, formed by melted rock that slowly cooled, said Vivian Sun (Jet Propulsion Laboratory) during her overview presentation March 7th at the Lunar and Planetary Science Conference. It’s still unclear whether the formations are specifically volcanic in origin (they might be impact melt, for example), or how Máaz is related to Séítah. Before the rover’s arrival, origin hypotheses included both igneous and sedimentary processes.

The Perseverance team has also used one of the two microphones aboard the rover — the first to land successfully on Mars — to measure the speed of sound on the Red Planet: 240 meters per second (540 mph), slightly less than Earth’s sound speed of 760 mph.

The exceedingly thin, carbon dioxide-based Martian atmosphere leads to what Baptist Chide (Los Alamos National Lab) and team call “a unique listening experience,” because frequencies above 240 MHz travel 10 m/s, meaning that high-pitched sounds will arrive earlier than bass. (Not that astronauts would remove their suits long enough to notice!)

Ingenuity, the Mars Helicopter

Meanwhile Ingenuity, the Little Technology Demonstration That Could, is delighting team members. After proving that powered flight on Mars is possible, the helicopter is spending its time scouting for the rover, identifying safe traverses and interesting rocks.

“I was really impressed with how well it worked and how useful it’s been,” Justin Simon (NASA Johnson Space Center) said.

The helicopter can’t venture far, because it communicates with Earth through the rover, explained Matt Golombek (Jet Propulsion Laboratory) during a virtual roundtable with the press. Its longest flight has been 630 meters (about 2,000 feet). The helicopter’s flights have become more efficient, though, as it no longer needs to scout out new airfields before landing.

Even after several months and a dust storm, Ingenuity shows no signs of wear, Golombek said: Dust hasn’t impeded its solar panels (probably because it’s flying around), and the only change in performance is that it can’t fly quite as far because atmospheric pressure is dropping as the seasons change.  

Perseverance will take more samples in the next week or so, then set off to explore the ancient delta in Jezero.

Zhurong: China’s Mars Rover

Elsewhere on Mars, China’s Zhurong rover, which arrived with the Tianwen 1 mission that launched in 2020, has been driving since May 2021. It’s exploring Utopia Planitia, a large, flat plain in the planet’s northern hemisphere. Scientists have interpreted the surface that the rover now trundles over as the sediments left behind by lakes, rivers, or even an ancient ocean.

The primary goal of the mission is an engineering one, to field and test an orbiter, lander, and rover in a single package. But Zhurong also carries six scientific payloads, and the team has used some of these instruments to investigate interesting soil, rocks, ridges, and craters along the way. In particular, they report on several ridges near the rover’s path. Wind has shaped these crescent-shaped ripples. But after combining the rover’s data with orbital images, the team surmised that these features are dusty, suggesting that whatever wind did the shaping has since quieted down. These results and others are published in Nature Astronomy and were also presented at the LPSC.

Thanks to the exceedingly flat terrain, the rover could continue to drive a long way. Indeed, it has already outlived its primary 90-sol (92-day) mission. Zhurong will continue to examine interesting features along the way as it trundles toward what might have been the shoreline of an ancient ocean.

Chang’e 5: Lunar Sample Return

The Chang’e 5 mission, launched in late 2020, performed a quick roundtrip mission to the Moon and back, taking less than a month to return 1.7 kilograms of lunar soil to Earth. Now members of the Chang’e 5 team and others who have analyzed the fragments have presented their finds at the ongoing Lunar and Planetary Science Conference (LPSC).

Chang’e 5 landed in the northern part of Oceanus Procellarum, which was already known to have hosted the most recent volcanic eruptions on the Moon. Indeed, the samples collected indicate a volcanic origin, probably a single eruption that occurred some 2 billion years ago. Based on the sample analysis, that eruption drew magma from the shallow mantle not too far beneath the surface. The samples will ultimately help scientists understand how the Moon has cooled over time.

Meanwhile, a spectrometer aboard the lander made the first-ever in situ detection of water on the lunar surface. (Technically, what the instrument detected was the 2.85 micron absorption line indicating the presence of hydroxyl groups, usually associated with water.)

Interactions between solar wind particles and the lunar regolith probably created the water, though it’s worth noting that it’s likely chemically bound — otherwise it wouldn’t have stuck around, unlike the water ice thought to exist in permanently shadowed craters at the Moon’s poles. Chang’e 5’s detection confirms studies from orbit that suggested water could, in some form, survive on the Moon’s dayside.

…And More

Other missions continue apace elsewhere on and around Mars: The UAE’s Hope Probe is transmitting global data on the Red Planet. And the Insight lander’s SEIS instrument continues to collect seismic data, now at 1,300 shakes and counting. Most are detected at night, when the atmosphere is calmer and less wind shakes the SEIS housing. The vast majority of these (1,100) are nearby, noted as high-frequency quakes. But two were stronger, with magnitudes of 4.1 and 4.2, respectively. These could help inform models of the Martian core.

Camille M. Carlisle and Monica Young contributed to the reporting.

Advertisement