Tag Archives: drill

Drill issues at Curiosity

The recent failure by Curiosity to drill has caused engineers to stop the rover in its tracks while they analyze the cause of the problem.

The rover team learned Dec. 1 that Curiosity did not complete the commands for drilling. The rover detected a fault in an early step in which the “drill feed” mechanism did not extend the drill to touch the rock target with the bit. “We are in the process of defining a set of diagnostic tests to carefully assess the drill feed mechanism. We are using our test rover here on Earth to try out these tests before we run them on Mars,” Curiosity Deputy Project Manager Steven Lee, at NASA’s Jet Propulsion Laboratory in Pasadena, California, said Monday. “To be cautious, until we run the tests on Curiosity, we want to restrict any dynamic changes that could affect the diagnosis. That means not moving the arm and not driving, which could shake it.”

Two among the set of possible causes being assessed are that a brake on the drill feed mechanism did not disengage fully or that an electronic encoder for the mechanism’s motor did not function as expected. Lee said that workarounds may exist for both of those scenarios, but the first step is to identify why the motor did not operate properly last week.

Though they do not say so, the problem is almost certainly related to a fundamental design flaw in the drill’s design that causes intermittent short-circuits when they use it, and has the possibility of shorting out the entire rover if they are not careful.

Drill design flaw source of short circuit on Curiosity

NASA engineers have confirmed that the rover’s drill is the source of the intermittent short circuit that forced them to shut down Curiosity temporarily.

“The most likely cause is an intermittent short in the percussion mechanism of the drill,” Erickson said in a statement. (Curiosity’s drill doesn’t simply rotate; it hammers into rock, via that percussion mechansism, as well.) “After further analysis to confirm that diagnosis, we will be analyzing how to adjust for that in future drilling.” A brief short occurred during a test on Thursday (March 5) that used the drill’s percussive action, NASA officials explained.

This is not a surprise, as it has been known since before launch that a design flaw in the drill could cause short circuits, possibly serious enough to permanently shut down the rover. They have thus used the drill much less than they had originally planned, and with great care.

Once they get a handle on the specifics causing this short, they say that Curiosity will go back into operation. However, I suspect that they may no longer use the drill, or if they do, they will use it under very very very limited circumstances.

Engineers commanded Curiosity to drill its third drill hole on Tuesday on what looks like an outcrop of sandstone in Gale Crater.

Engineers commanded Curiosity to drill its third drill hole on Tuesday on what looks like an outcrop of sandstone in Gale Crater.

This hole is shallow and is merely a test to see if a deeper full bore would be worthwhile geological.

That Curiosity has only drilled three holes, and is now only doing a test bore first is partly because engineers fear that using the drill too much will cause a short circuit that will disable the rover entirely. This fear is because of a design flaw in the construction of the rover and the drill.

After resuming drilling in Seattle — and only going four feet — Bertha has been stopped again.

After resuming drilling in Seattle — and only going four feet — Bertha has been stopped again.

High temperatures near the machine’s cutting face prompted contractors to stop mining after the drill advanced a total of 4 feet in test runs Tuesday and Wednesday. And that ended Bertha’s attempt to resume mining after an eight-week layoff.

The earlier stoppage remains unexplained. They found some concrete chunks and steel pipe sections in the way, but nothing that could have explained why the drill was blocked. Now the high temperatures pose a more significant problem, as they suggest there is something technical wrong with the giant drill.