NASA’s Mars Probe: Ejects Martian Pebbles

The team has made good progress in implementing the initial recovery measures outlined last week. Our first success: the top two pebbles were removed from the bit circuit during testing. This is great news, as this tiny splinter is believed to be the cause of the failed transfer of drill bits and sample tubes to the carousel again on December 29. Our second success: We appear to have removed most – if not all – of the remaining hollow rock in the 261 sample tubes.

Here are the latest…

Grind in circular bits

On Monday, January 17th, WATSON cameras recorded a carousel of cut and gravel – and also took pictures under the rover to determine what was there before the recovery strategy was implemented. Later that same day of Sol, we rotated the cut-off carousel about 75 degrees before returning it to its original position. WATSON imaging showed that the two upper stones had been removed during the procedure. We also received Tuesday night a second batch of images appearing below the rover, showing two new pebbles on the surface, showing that the ejected pebbles made it through the pie bits and back to the surface.

Mars is the second smallest planet in our solar system and the fourth planet from the sun. Iron oxide is prevalent in Mars’ surface resulting in its reddish color and its nickname “The Red Planet.” Mars’ name comes from the Roman god of war.

“>Mars As planned.

Rotate the circular bit for persistence: The annotated GIF depicts a bit-spin test of ductility in which two of the four rock fragments are removed. The five images that make up the GIF were acquired by WATSON rover imager on January 17, 2022. Credit: NASA/JPL-Caltech/MSSS

The other two pegs, which are located under the small circle, remain. It is interesting to note that some of the initial experiments carried out on our test bed on Earth indicated that the location of the two remaining gravel might not be much of a problem operating the bit carousel, but we are continuing to analyze and test to confirm this.

Sample remaining in the tube

On Saturday, January 15th, the team conducted an experiment using persistence rotary drill. After the robotic arm directs the auger with the open end of sample tube 261 at an angle of about 9 degrees below the horizontal plane, the rover’s axis of rotation rotates and then lengthens. Our awesome Mastcam-Z (which has video capabilities previously used to document some of Ingenuity’s journey) captures the action. The image from the experiment shows a small amount of sample material falling from the drill bit/sample tube. Later on the same Sol day, the bits were placed perpendicular to the ‘Isol’ (the rock that provided this final core) to see if any additional samples would fall under the influence of the gravitational force. However, imaging of the Mastcam-Z inside 261 after subsequent maneuvers showed that it still contained some samples.

Perseverance kicking rock shards

Perseverance of removing stone shards: A portion of the grained rock sample was removed from a rotary hammer drill aboard NASA’s Perseverance spacecraft on Mars. Image collected by the Mastcam-Z rover instrument on January 15, 2022. Credit: NASA/JPL-Caltech/ASU/MSSS

Since some of the samples had been lost, the team decided it was time to return the remaining samples to Mars and hopefully empty the tubes completely to prepare them for another sampling attempt. On Monday, January 17, the team ordered another operation of the rotary percussion drill in an attempt to remove more material from the tube. Since the open end of the tube is still pointing to the surface, we basically dump it for 208 seconds – via the drill tap function. Mastcam-Z images taken after the incident show that some parts of the sample were thrown to the surface. Is tube 261 free of rock samples? We have a new Mastcam-Z image looking at the bottom of the drill bit in the sample housing showing little, if any, debris from the grained rock sample. The sample tubes are cleaned for reuse by the project.

The persistence sample tube looks clean

The persistence tube sample looks clean: This image, taken by the Mastcam-Z camera aboard NASA’s Mars rover on January 20, 2022, shows that the rover managed to remove most of the rough rock remains from the drill-mounted sample tube. Source: NASA/JPL-Caltech/ASU/MSSS

future movements

The team is still reviewing the data and discussing next steps. Like all Mars missions, we faced some unexpected challenges. Each time, our team and rover have lived up to the occasion. We expect the same results this time – by taking additional steps, analyzing the results, and then moving forward, we plan to complete this challenge and return to exploration and sampling at Jezero Crater.

Written by Rick Welch, Deputy Project Manager at

Established in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States Federal Government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program, as well as aeronautics and aerospace research. It’s vision is “To discover and expand knowledge for the benefit of humanity.”

“> NASAJet Propulsion Laboratory.

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