After this, they can start a more comprehensive study of the planet
NASA’s Curiosity rover has conducted a new drill method on Mars, marking the first operation of the rover’s drill since a motor problem began acting up more than a year ago.
This early test produced a hole about a one-centimetre deep at a target called Lake Orcadie — not enough for a full scientific sample, but enough to validate that the new method works mechanically, NASA said on Wednesday.
This was just the first in what will be a series of tests to determine how well the new drill method can collect samples. If this drill had achieved sufficient depth to collect a sample, the team would have begun testing a new sample delivery process, ultimately delivering to instruments inside the rover.
Curiosity has used its drill to collect samples 15 times since landing in 2012. Then, in December of 2016, a key part of the drill stopped working.
If the previous method was like a drill press, holding the drill bit steady as it extends into a surface, it is now more freehand. The rover is using its entire arm to push the drill forward, re-centring itself while taking measurements with a force sensor. That sensor was originally included to stop the rover’s arm if it received a high-force jolt, NASA said.
It now offers Curiosity a vital sense of touch, preventing the drill bit from drifting sideways too much and getting stuck in a rock.
“We’re now drilling on Mars more like the way you do at home,” said Steven Lee, Deputy Project Manager at NASA’s Jet Propulsion Laboratory, Pasadena, California.
“Humans are pretty good at re-centring the drill, almost without thinking about it. Programming Curiosity to do this by itself was challenging — especially when it wasn’t designed to do that,” Lee added. IANS
Giant rocks from space are falling from the sky more than they used to, but don’t worry.
For the past 290 million years, large asteroids have been crashing into Earth more than twice as often as they did in the previous 700 million years, according to a new study in Thursday’s journal Science.
But no need to cast a wary glance up. Asteroids still only smack Earth on average every million or few million years, even with the increased crash rate. NASA’s list of potential big space rock crashes shows no pending major threats. The biggest known risk is a 4,200-foot (1.3-km) wide asteroid with a 99.988 percent chance that it will miss Earth when it whizzes very near here in 861 years.
Tell that to the dinosaurs. Most scientists think dinosaurs and a lot of other species went extinct after a huge space rock crashed into Central America about 65 million years ago.
“It’s just a game of probabilities,” said study lead author Sara Mazrouei, a University of Toronto planetary scientist. “These events are still rare and far between that I’m not too worried about it.”
Mazrouei and colleagues in the United Kingdom and United States compiled a list of impact craters on Earth and the moon that were larger than 12 miles (20 km) wide and came up with the dates of them. It takes a space rock that’s half a mile (800 meters) wide to create holes that big.
The team counted 29 craters that were no older than 290 million years and nine between 291 million years and 650 million years old.
But we can see relatively few big craters on Earth because the planet is more than 70 percent ocean and past glaciers smoothed out some holes, said University of Toronto planetary scientist Rebecca Ghent, a study co-author.
Extrapolating for what can’t be seen brings the total to about 260 space crashes on Earth in the last 290 million years. Adding in other factors, the science team determined that the current space crash rate is 2.6 times more than the previous 700 million years.
Craters older than 650 million years are mostly wiped off on Earth by glacial forces so the scientists used impact craters on the nearby moon as a stand-in for holes between 650 million and 1 billion years old. The moon is a good guide for estimating Earth crashes, because it is close enough to be in the same bombardment path and its craters last longer.
So what happened nearly 300 million years ago?
“Perhaps an asteroid family was broken up in the asteroid belt,” Mazrouei speculated. The space rocks then headed toward the Earth and moon, and the planet got slightly more because it is a bigger target and it has higher gravity, Ghent said.
Outside scientists are split about the research. Jay Melosh at Purdue said he found the number of craters too small to come to a reasonable conclusion, but Harvard’s Avi Loeb said the case was convincing.
Humans might not have emerged without mass extinctions from space rocks about 250 million and 65 million years ago, Loeb said in an email, adding, “but this enhanced impact rate poses a threat for the next mass extinction event, which we should watch for and attempt to avoid with the aid of technology.”
“This demonstrates how arbitrary and fragile human life is,” Loeb wrote. (VOA)