Curiosity pioneers new drilling technique on Mars
Sen—Curiosity's next few tastes of the mountain it is drilling into at Mars will use a new "low percussion" drilling technique to better preserve the underlying rock.
The NASA rover, which has been exploring Gale Crater since August 2012, tested out the new procedures on a sample known as Mojave 2. Mission managers noted that layered rocks such as this one appear quite fragile in the pictures, leading to ideas on how best to take samples without breaking them.
"This was our first use of low-percussion drilling on Mars, designed to reduce the energy we impart to the rock," stated John Michael Morookian, the team's surface science and sampling activity lead for the Pahrump Hills campaign at the Jet Propulsion Laboratory in California. "Curiosity's drill is essentially a hammer and chisel, and this gives us a way not to hammer as hard."
Curiosity drilled into this rock target, called Mojave 2, in January 2015. Image credit: NASA/JPL-Caltech/MSSS
The new drilling procedures essentially call for the rover to use its lowest energy setting right from the beginning, rather than starting with a setting a few levels up. Curiosity has six settings on its drill that have a nearly 20-fold range in energy. The drill has only been used three times before Curiosity reached Mount Sharp (Aeolis Mons), its ultimate science goal, late last year.
On those three occasions and when the drill was used once at Mount Sharp, Curiosity began its investigations at the drill's Level 4. The first rock probed at Mount Sharp broke under this pressure. The new algorithm instead starts at Level 1 and only progresses upwards if drilling proves too slow.
At its first target under the new protocol, Curiosity pushed into Mojave 2 in only 10 minutes, using Levels 1 and 2 on the drill. The resulting hole is 2.6 inches (6.5 centimeters) deep. Managers are still figuring out what intriguing crystals in the rock mean for its formation history. They are not sure if the crystals are salt from a long-ago drying lake, or represent other substances.
Curiosity has spent the last few weeks exploring an outcrop at the base of Mount Sharp called Pahrump Hills. It has done three rounds of investigation: a survey where the rover took pictures of the area, a more close-up examination of certain areas using tools such as a brush, and the drilling—usually considered the most complicated step, and justified only at areas of the most scientific interest. Samples from the drill are typically placed into a small "oven" in the rover that breaks it down into elements for analysis.
The rover's goal is to better understand if the Red Planet had or has habitable environments. It has already uncovered evidence of past water in its travels, but Mount Sharp is considered the keystone element in that quest. By better understanding how the mountain was formed, scientists hope to better generalize the climate in that region over time.
As Curiosity continues through its first extended mission, another concern is making sure that the rover remains healthy for its investigations. Controllers have already had problems with wheels tearing up faster than planned, which is forcing them to pick routes carefully to avoid accelerating the damage. In a few more years, power will need to be rationed as the rover's nuclear generator loses potency.