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Perseverance weighs about one ton, it is as big as a car. But what is inside the vehicle that weighs so much? Is the payload only the instruments hanging from the arm? Is all the remaining hardware (cameras, wheels, suspensions, RTG, ...) there just to move this payload on the surface?

I'm thinking that in the case of a one ton car, the payload is... 75 kg of driver, all the remaining hardware is to allow moving him from a place to another.

How well does that analogy apply to the Mars rover?

jumpjack
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  • I think it's a little weird to talk about a rover as a vessel for a payload. It's more analogous to an astronaut. We don't talk about a human astronaut being a vessel for its arms and brain. – called2voyage Mar 22 '21 at 16:20
  • Unless we're talking about something like the LRV whose primary function is carrying a human or separable cargo. – called2voyage Mar 22 '21 at 16:22
  • This is very broad, and also you can find lots of information on this topic with some simple web research. – GdD Mar 22 '21 at 16:22
  • That said, Perseverance is carrying several items intended for permanent offloading to the Martian surface. – notovny Mar 22 '21 at 17:09
  • A cars payload is much more then 75kg, though. My car can fit five people and has a large trunk where I can put a lot of cargo. That being said, even for a car, the most mass is in the car itself, not the payload -- chassis, fuel, tires, electronics, motors, AC, radio, lights, cables, fuel lines, brakes and whatnot. – Polygnome Mar 22 '21 at 20:37
  • There is enough information about this topic that it could fill an entire book (and perhaps someday it will). That is way too much for the space of a StackExchange answer, so this question is too broad and needs more focus. – DrSheldon Mar 22 '21 at 23:46
  • I always ask myself this question about spacecraft (Why the heck is this thing so big and heavy?) I am glad you've asked this and sorry if people choose to prevent it from being answered. I think it will be well and readily answered if given even a few days. Insta-closing will prevent those answers and become a self-fulfilling prophesy. Voting to keep open! and to allow for answers to be posted. – uhoh Mar 23 '21 at 02:56
  • Personally, I'd love to see a photo of "under the hood" - Perseverance with its chassis open. – SF. Mar 23 '21 at 08:58

2 Answers2

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There's quite a few devices installed inside the chassis.

  • Rover's own "essentials" necessary for the rover to operate - the computer, radio electronics, batteries for burst power usage, power supply units, inertial sensors etc.
  • MOXIE - the 'oxygen maker', a test article, downscaled device that would supply Mars base with oxygen made from atmospheric CO2.
  • RIMFAX (Radar Imager for Mars' Subsurface Experiment) - A ground-penetrating radar that will provide centimeter-scale resolution of the geologic structure of the subsurface.
  • electronics "backend" for most of scientific payload devices - Supercam, SHERLOC, PIXL, Mastercam-Z all have the electronics for processing the sensor data and controlling the sensors housed inside the chassis.
  • the sample storage carousel and the robot arm that services it (thanks Organic Marble).
  • and in the end, 6.27 kilograms of dead weight ballast that brings the center of mass where required. source

Locations of the respective parts can be found on the diagram published by JPL.

enter image description here

Compi provided a link to the photo of the inside of the chassis, from NASA:

enter image description here

SF.
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Like a car body, the rover body is a strong, outer layer that protects the rover's computer and electronics (which are basically the equivalent of the rover's brains and heart). The rover body thus keeps the rover's vital organs protected and temperature-controlled. The warm electronics box is closed on the top by a piece called the Rover Equipment Deck. The Rover Equipment Deck makes the rover like a convertible car, allowing a place for the rover mast and cameras to sit out in the Martian air, taking pictures with a clear view of the terrain as the rover travels.

Alexis Rogozinski
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  • Welcome to Stack Exchange! This is an interesting and informative answer! Do you think you can add some supporting links or cite some sources? Stack Exchange answers should include those to help readers determine if the information is correct and to do to further reading. Thanks! – uhoh Mar 23 '21 at 03:01