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Science Instrument of Mars 2020 Perseverance Rover

MOXIE of the Mars 2020 Perseverance Rover Part 1

Mars’ atmosphere has around 96% carbon dioxide and there is only 0.13% oxygen. Therefore, it is not suitable for humans to breathe. To find out if it is possible for human exploration on Mars, one of the most important things is to figure out how to make oxygen, not only for humans to breathe but also for helping with burning rocket fuel. The Mars 2020 Perseverance rover‘s MOXIE (short for the Mars Oxygen In-Situ Resource Utilization Experiment) is the instrument that will make oxygen from Mars’ atmosphere. It is like an artificial plant, breathing in carbon dioxide and breathing out oxygen (also some byproducts such as carbon monoxide).

The Mars 2020 Perseverance rover‘s MOXIE instrument is located on the inside of the Mars 2020 Perseverance rover‘s right front belly. It has a mass of 17.1 kg, but due to different gravitational forces between Earth and Mars, MOXIE weighs 37.7 lbs on Earth but 14.14 lbs on Mars. The Perseverance Mars Rover’s MOXIE is expected to operate its first mission within 30 sols after it lands on Mars and passes all the health checkups.

The Mars 2020 Perseverance rover‘s MOXIE is inside of the rover’s body, and you cannot see it from the outside, so our 1:2 Perseverance Mars Rover Replica might not replicate it, or we will replicate it after all the other components are completed. If we do replicate the PMars 2020 Perseverance rover‘s MOXIE instrument, our Mars Rover replica‘s MOXIE will not actually make oxygen, but the appearance structure will be replicated.

Interestingly, the Mars 2020 Perseverance rover‘s MOXIE has 2 microphones so we can hear it making oxygen on Earth. The reason for the microphones is because MOXIE runs by a motor. By listening to the motor running, engineers will know MOXIE is working. Even though our 1:2 Perseverance Mars Rover Replica might not replicate the MOXIE instrument, we may add a speaker inside of the Mars Rover Replica‘s body and make the motor running sound effects to simulate the MOXIE’s working sound.

The Mars 2020 Perseverance rover‘s MOXIE instrument only has a size of a car battery but once it is operating. If we replicate it on our Perseverance Mars Rover replica, it will be half the size of the real Mars 2020 Perseverance rover‘s MOXIE. When operating, the Mars 2020 Perseverance rover‘s MOXIE will use up to around 30% of the Mars 2020 Perseverance rover‘s power, and the heat generated will be so hot that the scientists had to insulate it. Otherwise, the instrument on board or even the whole of Mars 2020 Perseverance rover will get damaged. However, how hot it will get or how much voltage will be used are still to be found out during real operations on Mars.

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1:2 Perseverance Mars Rover Replica Design and Building Diary

Why 1:3? – Choosing the Size Ratio of the Perseverance Mars Rover Replica

When we first had the idea to build the Perseverance Mars Rover replica, we set the goal as making the Perseverance Mars Rover replica ultra-realistic – looks the same and moves the same as the Mars 2020 Perseverance Rover but with no science instruments.

We had some arguments about the size ratio at the beginning. 1:1, 1:2, and 1:3 seemed to be the three natural candidates.

1:1 Perseverance Mars Rover replica was eliminated first because it is too heavy and too expensive.  The Mars 2020 Perseverance Rover is 1,025 kg or 2,260 lb. The 1:1 Perseverance Mars Rover Replica will not as heavy as the real one but should be around 600 kg or 1,322 lb. The most tricky part is the spokes. The Mars 2020 Perseverance Rover’s spokes are made of titanium, however, it will be way too expensive for us to build the 36 spokes that way. If we use other materials, the building cost is still too high. Moreover, the heavyweight is a big challenge for all the connection structures which requires material and processing and assembly techniques up to a certain high level which is not proper for our first Perseverance Mars Rover replica project.

Unless we spent tons of effort doing simulations and tests in the physical world so as to be 100% sure that it is feasible for all the critical structures to bear the weight of the 1:1 Perseverance Mars Rover replica, any further effort in designing and building the 1:1 replica might be a waste of time. After all, we are not as rich as NASA. We cannot endure waste and risk more than we can afford at this stage.

Then the competition was between 1:2 and 1:3. We hesitated between these two options because each has its advantages and disadvantages and the scores were close. Technically speaking, the difficulties of building Perseverance Mars Rover replicas of these two ratio sizes were very close although the 1:2 did prevail a little bit on most aspects. However, since the 1:2 Perseverance Mars Rover replica is approximately 2.4 times larger than the 1:3, the cost of everything is at least doubled or even more.

On the other hand, the main challenge of the 1:3 comes from its relatively small size against its motorized parts, especially the iconic long arm that carries multiple sensors and cameras and the heavy drill set. Although it is not our goal to build any functional science instruments on our Perseverance Mars Rover replica, we do set the goal to build all the visible parts move the same way as those components of the Mars 2020 Perseverance Rover do. That’s saying that since the Mars 2020 Perseverance Rover can drill on Mars, our Perseverance Mars Rover replica should have the ability to drill on Earth, or at least drill like real.

There is a possibility that the weight of the 1:3 Perseverance Mars Rover replica’s arm was too heavy to be motorized without compromising the joint shapes simply because the arm joints need larger motors to lift the weight but its internal space won’t allow them to accommodate motors of such sizes. Of course, we did estimations and simulations about the torques required and the torques could be provided by the motors of suitable sizes. It turns out that the required and the provided are close. Therefore, we need the exact weight of the component which highly depends on the exact structure design. therefore, the only way to make sure we can make the 1:3 arm for the Perseverance Mars Rover replica was to complete the exact design if not build it physically. But we believe there is a good chance for the 1:3 Perseverance Mars Rover replica to achieve the pre-set goal.

Therefore, we decided to choose the 1:3 Perseverance Mars Rover replica as a start. It is the cheapest among the three candidates, and it is very likely to hit the goal.

Well, cheap is relative. Even the 1:3 Perseverance Mars Rover replica should cost us at least 200,000 USD before we can complete the first prototype. The 1:2 replica is around 300,000 USD while the 1:1 is around 500,000 USD.

>> Related Information

The original dimensions of the body box of the Mars 2020 Perseverance Rover are as follows.

  • Length 10 feet (3 meters)
  • Width 9 feet (2.7 meters)
  • Height 7 feet (2.2 meters)

Therefore, the dimensions of the body box of the 1:3 Perseverance Mars Rover replica are as follows.

  • Length 3 feet 4 inches (1 meter)
  • Width 3 feet (0.9 meters)
  • Height 2 feet 4 inches (0.73 meters)