The Mars Rover Curiosity Digs a Little Deeper
Add another word to your vocabulary of Martian geological exploration: thwacking…repeat, not fracking, but thwacking!
Thwack: to strike with or as if with something flat or heavy. (Merriam Webster's.)
On Wednesday, NASA held a press conference to announce another first in our robotic exploration of Mars. On February 8th, the rover Curiosity (of the Mars Science Laboratory mission) used its drill to bore a hole (maybe more correctly, used its thwacker to thwack a hole) into a slab of flat bedrock. The boring tool uses vibrating impacts to speed up the rock penetration of the rotating drill bit, not unlike a handheld impact drill, or a tiny jackhammer with a spinning tip.
The hole, 6.4 centimeters deep (about the length of my pinky finger), is aimed at delivering a sample of pulverized rock powder to Curiosity's onboard chemical analysis laboratories–more specifically, a sample from deeper into the rock than 5 centimeters, rock which has not been chemically altered by the weathering effects that the material at the outer surfaces endures.
The patch of bedrock chosen for this micro-excursion is thought to be ancient, making a probing of mere inches an excursion of perhaps millions of years into Mars' past–maybe far back enough to probe a time when liquid water existed on its surface. Regardless of whether it finds the watery signature of ancient surface liquid in this sample, exciting though that would be, the rover's mission is to probe Mars' geology to assess the past habitability of the planet–so we'll get what we get.
Though a 6.4 centimeter hole in bedrock barely sounds like scratching the surface, this hole bears the distinction of being the deepest we've dug into solid rock on Mars. And it's really no small feat. Perhaps to get an idea of what it takes to do this sort of prospecting, try it yourself: get an impact drill (one of those hand drills that vibrates up and down as it bores) with a one-inch masonry bit and try drilling/thwacking a 2.5 inch hold into an old piece of concrete (disclaimer: make sure it's your own concrete, not someone else's paving stone or patio–and be sure you're wearing proper eye protection gear). Now, if you've managed to do this, think about the fact that NASA has done this by remote control on Mars. Curiosity is doing some amazingly challenging work out there!
At this moment the pulverized tablespoonful of pristine bedrock awaits being delivered to the instruments on Curiosity that will unlock all of its tantalizing chemical secrets–but maybe that can be the subject of a press release event in the near future.