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Sample Handling System of Mars 2020 Perseverance Rover

Adaptive Caching Assembly of the Mars 2020 Perseverance Rover – part 1

The Mars 2020 Perseverance Rover‘s adaptive caching assembly is one of the three main components of the sample caching system. The other two main components are the robotic arm and the turret assembly, which are introduced in more detail in [Robotic Arm the Mars 2020 Perseverance Rover] and [Turret of the Mars 2020 Perseverance Rover].

The Mars 2020 Perseverance Rover‘s adaptive caching assembly is located inside of the rover and on the front of the body. There are mainly 6 sub-assemblies of the Mars 2020 Perseverance Rover‘s adaptive caching assembly: the sample tube storage assembly, the sample handling arm, the dispenser, volume, tube assembly, the vision station, the sealing station, and the bit carousel. For our 1:2 Mars Rover Replica, we will replicate the part on the front of the body, and we will try our best to perfectly replicate the part that is inside of the rover’s body.

The Mars 2020 Perseverance Rover‘s adaptive caching assembly’s sample tube storage assembly is for storing both empty sample tubes and filled sample tubes. Although they are placed together, there are sheaths to protect them from contaminating each other. There are a total of 39 sample tubes in the sample tube storage assembly.

The Mars 2020 Perseverance Rover‘s adaptive caching assembly’s sample handling arm is for transferring the sample tubes to different stations in the adaptive caching assembly or for moving the sample tubes to the bit carousel so that the sample tubes are inserted into the drill bits for sample caching purposes.

The Mars 2020 Perseverance Rover‘s adaptive caching assembly’s dispenser, volume, tube assembly is to calculate the number of samples collected and to reduce possible contamination. There are 3 sample tubes in the dispenser, volume, tube assembly. There are 7 seal dispensers, and each seal dispenser has 7 seals, so there are 49 seals in total, 7 of which are spares.

The Mars 2020 Perseverance Rover‘s adaptive caching assembly’s vision station not only takes photos of the sample cached but also performs a second-time calculation for the amount of each sample collected.

The Mars 2020 Perseverance Rover‘s adaptive caching assembly’s sealing station is to seal a sample permanently by triggering seals in the sample tubes.

The Mars 2020 Perseverance Rover‘s adaptive caching assembly’s bit carousel is to keep all the drill bits and helps to insert a sample tube into a drill bit for sample caching.

For our 1:2 Mars Rover Replica, we will try our best to perfectly replicate these 6 sub-assemblies. Although they will not have the same functions as the real Mars 2020 Perseverance Rover‘s adaptive caching assembly, they will be fully motorized and you can simulate the sample handling movement with the remote control.

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Sample Handling System of Mars 2020 Perseverance Rover

Robotic Arm the Mars 2020 Perseverance Rover

The Mars 2020 Perseverance Rover‘s robotic arm is located on the front of the rover’s chassis. It has a length of 7 feet or 2.1 meters, which is the same length as its predecessor, the Curiosity rover.  Our 1:2 Mars Rover Replica‘s robotic arm has a length of 3.5 feet or 1.05 meters. The Mars 2020 Perseverance Rover‘s robotic arm wields a rotating 45kg (or 99 lbs) turret assembly, which is 15kg (or 34 lbs) heavier than the Curiosity rover’s turret assembly because it carries bigger science instruments and a bigger corer for drilling compared to the Curiosity rover. The weight of our Mars Rover Replica‘s robotic arm will not be that heavy, because the instruments on it will only be decorations (but ultra-realistic decorations), and the material we use will be lightweight.

The purpose of the Mars 2020 Perseverance Rover‘s robotic arm is to help with exploring the Martian surface and collecting valuable Martian samples. It mimics the human arm – it has joints at its “shoulder”, “elbow” and “wrist” for maximum degrees of freedom. Our Mars Rover Replica‘s robotic arm will also have as many degrees of freedom as the real Mars 2020 Perseverance Rover‘s robotic arm. If the Mars 2020 Perseverance Rover is a human scientist, then the robotic arm is his human arm. At the end of the robotic arm, there is a turret assembly or a hand, and on the hand, there are the science instruments (SHERLOC, WASTON, PIXL), the gDRT, the Corer, and the ground contact sensor which are for Martian rock and soil sample caching. The gDRT and the ground contact sensor are introduced in [Turret of the Mars 2020 Perseverance Mars Rover].

There are some small motors or rotary actuators on the Mars 2020 Perseverance Rover‘s robotic arm, and with these actuators, the Mars 2020 Perseverance Rover‘s robotic arm has 5 degrees of freedom or 5 flexible joints: the shoulder azimuth joint, the shoulder elevation joint, the elbow joint, the wrist joint and the turret joint. Our Mars Rover Replica‘s robotic arm will also have these motors – not the same type or the same size, but the function of the motors is the same –  so that the Mars Rover Replica‘s robotic arm is also 5 degree of freedom. The flexibility of the Mars 2020 Perseverance Rover‘s robotic arm allows it to rotate the turret accurately to a location of interest so that the corer can start its initial abrading operation for the later sampling process, or for the science instruments analyzing process.

After the science team on Earth decides which rocks or regolith to sample, Mars 2020 Perseverance Rover will give the robotic arm the “go” for sample caching. The Mars 2020 Perseverance Rover’s robotic arm will rotate the corer to an angle that is best for the drill bit to operate. Depending on the condition of the drilling site, the drill will choose the rotary mode or the percussive mode for the sample caching. After the sample rocks or regolith are collected, the Mars 2020 Perseverance Rover’s robotic arm will transfer the sample tubes to the bit carousel for the later processes. Although the Mars Rover Replica‘s robotic arm doesn’t have the function like the real Mars 2020 Perseverance Rover, users can control the Mars Rover Replica to drive and mimic the movement of the robotic arm.

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Sample Handling System of Mars 2020 Perseverance Rover

Drills of the Mars 2020 Perseverance Rover

There are 3 types of drill bits that the Mars 2020 Perseverance Rover‘s bit carousal carries. The first type is the coring bit, the second type is the regolith bit and the third type is the abrading drill bit – or the abrader. The three types of drill bits are interchangeable depending on what the target samples are or the purpose of the specific operation. There are 6 coring bits,1 regolith bit, and 2 abraders in the Mars 2020 Perseverance Rover‘s bit carousal. In addition, there is one more launch abrading bit which is located in the Corer on the end of the turret assembly.

The Mars 2020 Perseverance Rover‘s drills are designed to have a rotary percussive motion as an efficient way to extract scientifically selected rock and soil samples from the Martian surface. Our 1:2 Perseverance Mars Rover Replica‘s drills will simulate the rotary percussive motion, but the drills cannot actually drill and collect rock samples like the real Mars 2020 Perseverance Rover‘s drills.

The Mars 2020 Perseverance Rover‘s coring drill bit has a height of 228 mm or 8.98 inches, and the diameter of each of the Mars 2020 Perseverance Rover‘s drills is 1 inch or 27mm. The drill bit’s body material is custom 465 stainless steel coated with titanium nitride. The coring bits collect coring samples – cylindrical-shaped rock samples and will preserve the stratigraphy layers as they are so that in the future if the samples are returned to Earth, scientists can study the stratigraphy of the collected Martian rocks. For our Mars Rover Replica, the coring drill bits will have a height of 114mm, and a diameter of 0.5 inches. The material for our Mars Rover Replica‘s coring drill bit will also be stainless steel but we might not replicate the titanium nitride coating.

Each sample core the Mars 2020 Perseverance Rover collects has a length of 60mm or 2.4 inches, the sample core’s diameter is 0.5 inches or 13mm, and the Martian sample itself is around 10 to 15 grams every tube. For our 1:2 Perseverance Mars Rover Replica, the sample tubes will be empty, and you can put some rocks or sands in them for decoration.

Unlike the Mars 2020 Perseverance Rover‘s coring drill bits, the Mars 2020 Perseverance Rover‘s regolith drill bits, with a height of 185.2mm, or 7.29 inches, collect regolith, which means broken rock materials and dust, but the sealing, transferring, and storing processes are the same as the coring drill bits. For our Mars Rover Replica, the regolith drill bits will have a height of 92.6 mm or 3.645 inches.

Different from both the Mars 2020 Perseverance Rover‘s coring drill bits and regolith drill bits, the Mars 2020 Perseverance Rover‘s abrading drill bits don’t collect any samples. The abrader has a height of 130.7mm or 5.15 inches and its job is to abrade or scrape off the top layer of the rocks in order to expose the surface feature that is not exposed to weathering. Then the science instruments will study the exposed rocks and soils for scientific purposes. The two abraders are planned for 74 missions, and they have an optimized pattern design for the teeth so that when scaping the top layer off of the rocks, the exposed surface will be smooth, which is more convenient for the later analysis. Our Perseverance Mars Rover Replica‘s abrading drill bits will perfectly replicate the appearance structure of the Mars 2020 Perseverance Rover‘s abrading drill bits and our Perseverance Mars Rover Replica‘s abrading drill bits have a height of 65.35 mm, or 2.575 inches.

The Mars 2020 Perseverance Rover‘s launch abrading bit has a height of 108.1mm, or 4.26 inches. The launch abrading bit is pre-installed into the Corer chuck at the center of the end of the turret. It provides a sealing cover for the Corer chuck, and additional abrading power if needed. Our Perseverance Mars Rover Replica‘s launch abrading bit will perfectly replicate the appearance structure of the Mars 2020 Perseverance Rover‘s launch abrading bit and our Perseverance Mars Rover Replica‘s launch abrading bit will have a height of 54.05 mm, or 2.13 inches.

Structurally, the Mars 2020 Perseverance Rover‘s three types of bits have mostly the same features such as the percussion interface and bit sleeve. The coring bits and regolith bits will drill into the Martian surface and collect samples, so they have a sample tube interface for exchanging tubes. However, the Mars 2020 Perseverance Rover‘s abraders don’t have the sample tube interface since they don’t collect actual samples. For the same reason, the coring bit and regolith bit can house a sample tube inside but the abrading bits don’t have this feature. Our 1:2 Perseverance Mars Rover Replica will perfectly replicate the drill bits’ appearance structure but they won’t have the actual functions that the real Mars 2020 Perseverance Rover‘s drills do.