JPL engineers follow the testing of the Perseverance Rover’s Sample Caching system in this video clip. See below for the full video. Credit: NASA / JPL-Caltech
Two astronauts collected moon rocks on Apollo 11. It takes three robotic systems working together to collect the first one Mars rock samples for return to Earth.
The monsters that Apollo 11 brought to Earth from the Moon were humanity’s first from another celestial body. NASAThe Mars 2020 Perseverance rover mission collects the first samples from another planet (the red one) to return to Earth on subsequent missions. Instead of astronauts, the Perseverance rover will rely on the most complex, capable and cleanest mechanism ever sent into space, the Sample Caching System.
The last 39 of the 43 sample tubes at the heart of the sampling system, along with the storage unit that will contain them, were loaded aboard NASA’s Perseverance rover at Kennedy Space Center in Florida on May 20. (The other four tubes were already loaded at different locations in the Sample Caching System.) The integration of the final tubes was one of the last important steps in preparation for the Mars Perseverance Rover launch.
“While you may be amazed at what was accomplished in the days of Apollo, they had one thing ahead of them that we don’t: boots on the ground,” said Adam Steltzner, chief engineer of the Mars 2020 Perseverance rover mission. at NASA’s Jet Propulsion Laboratory in Southern California. “To collect the first samples from Mars for return to Earth, instead of two astronauts, we have three robots that have to work with the precision of a Swiss watch.”
The first samples from the moon were collected by two astronauts. The first samples to be collected for the eventual return to Earth from Mars will take three robots aboard the Perseverance rover operating as one. Together they form the mission’s Sample Caching System described in this video. Image credit: NASA /JPL-Caltech
While many people think of the Perseverance rover as one robot, it actually resembles a collection of robots working together. The Sample Caching System itself, which is located at the front of the Perseverance rover, consists of three robots, the most visible of which is the 2 meter long (2 meter long) robotic arm. The five-armed arm is bolted to the front of the rover’s chassis and carries a large dome with a rotary percussion drill to collect core samples of Martian rock and regolith (fractured rock and dust).
The second robot looks like a small flying saucer built into the front of the rover. Called the bit carousel, this device is the ultimate middleman for all Mars monster transactions: it delivers drills and empty sample tubes to the drill and will later move the sample-filled tubes to the rover’s chassis for review and processing.
The third robot in the Sample Caching System is the 1.6-foot (0.5-meter) sample-handling arm (known by the team as the ‘T. rex arm “). It is located in the abdomen of the rover and continues where the bit carousel ends, moving sample tubes between storage and documentation stations and the bit carousel.
Clocklike Precision
All these robots have to turn with a bell-shaped precision. But where the typical Swiss chronometer has fewer than 400 parts, the Sample Caching system has more than 3,000.
“It sounds like a lot, but you start to realize the need for complexity when you consider that the Sample Caching System’s job is to autonomously drill into Mars rock, extract intact core samples, and then seal them hermetically in hypersterile vessels that are essentially free of any organic matter from Earth that could impede future analysis, “said Steltzner.” In terms of technology, this is the most complicated, most advanced mechanism we’ve ever built, tested and prepared for space flights. “
The objective of the mission is to collect a dozen or more monsters. So how does this labyrinthine collection of motors, planetary gearboxes, encoders and other devices of three robots, the size of a steamer trunk, all meticulously work together to accommodate them?
“Essentially, after our rotary percussion drill takes a core sample, it will turn around and dock with one of the bit carousel’s four clutch cones,” said Steltzner. “Then the bit carousel spins that Martian-filled drill and a sample tube down into the rover to a location where our monster-handling arm can grab it. This arm pulls the filled sample tube out of the drill and frames it for a camera in the sample caching system. “
After the sample tube is imaged, the small robotic arm moves it to the volume assessment station where a ramrod is pressed into the sample to measure its size. “Then we’ll go back and take another picture,” said Steltzner. “Then we take a seal – a small plug – for the top of the sample tube and go back to take another picture.”
The Sample Caching System then places the tube in the sealing station, where a mechanism hermetically seals the tube with the cap. “Then we’ll take the tube out,” added Steltzner, “and we’ll take it back to the store where it first started.”
The design and manufacture of the system and its integration into Perseverance has been a seven-year venture. And the work is not finished yet. As with everything else on the rover, there are two versions of the Sample Caching System: a technical test model that will stay here on Earth and the flight model that will travel to Mars.
“The engineering model is identical to the flight model in every way, and our job is to break it down,” said Kelly Palm, the Sample Caching System integration engineer and Mars 2020 test lead at JPL. “We do that because we would rather see things wear out or break on Earth than on Mars. That’s why we put the technical test model to the test to inform our use of its flight twin on Mars. “
To this end, the team uses different rocks to simulate types of terrain. They drill them from different angles to anticipate every conceivable situation the rover might be in, where the science team might want to collect a sample.
“Every now and then I have to take a moment to think about what we are doing,” said Palm. ‘Just a few years ago I was at university. Now I am working on the system that will be responsible for collecting the first samples from another planet for return to Earth. That’s pretty cool. “
About the mission
Perseverance is a robot scientist who weighs about 2,260 pounds (1,025 kilograms). The rover’s astrobiology mission will look for signs of past microbial life. It will characterize the planet’s climate and geology, collect samples for future return to Earth, and pave the way for human exploration of the red planet. Perseverance increased on July 30, 2020 and will land in the Jezero Crater on Mars on February 18, 2021.
The two subsequent (follow-up) missions needed to return the collected samples from the mission to Earth are currently being planned by NASA and the European Space Agency.
The Mars 2020 Perseverance rover mission is part of a larger program that includes missions to the moon as a way to prepare for human exploration of the Red Planet. NASA is tasked with returning astronauts to the moon by 2024 and will establish a sustainable human presence on and around the moon by 2028 through the agency’s Artemis lunar exploration plans.