Project Ceres Ep. 2: Prototype

This new project tasked me, as well as my two partners Matthew and Josh, to create a vehicle that will travel 5 kilometers in total to and back two points on the surface of any celestial body of our choice, and we chose Ceres.

Our definition statement is: A team of astronauts need a form of transportation that is able to efficiently cover a minimum round trip distance of 5km from point A to point B. This form of transportation must be able to overcome the 3% Earth gravity of Ceres, below -105°C temperatures, rocky terrain and make the most of its limited power sources.

–

Ideation

To create a vehicle that fulfills these requirements, our team brainstormed many potential ideas. These are a few of my favourites that we considered but did not decide to go with, and why.

1. Jet propulsion

This idea is pretty logical and has been used by vehicles before to explore other extraterrestrial surfaces. Since Ceres has almost no atmosphere and is an extremely low-gravity environment, about 3% that of Earth’s, levitating a vehicle off the surface and moving it requires minimal energy. The idea was to lift the vehicle with small rocket boosters when it had to move and use these to change directions, slow down, and control its motion.

This idea was scrapped for two reasons. Even though a very small amount of fuel is consumed, rocket boosters still burn through much more fuel than an efficient engine. Since fuel has to be made through water found as ice inside Ceres’ rocks, and this process takes a long time and produces limited results, relying solely on rocket boosters would be inefficient. Furthermore, rocket boosters are less reliable than traditional engines. They take more steps to start up and are much harder to maintain between uses. Having the vehicle break down in the middle of nowhere on a cold, barren exoplanet is definitely not ideal. Also, if the boosters malfunction in flight, it would cause much more damage than a vehicle malfunctioning on the ground, since it would crash. Because of these two main restraints, we decided to scrap this idea.

2. Spider legs

Another idea we heavily considered was giving the vehicle spider-like legs. This would come with many benefits. For example, if the vehicle were to encounter rough, uneven surfaces or a hill, it could more easily traverse them than wheels could. We also discussed adding tools to each one of the legs. For example, one leg could have a spectrometer to measure wavelengths or radiation if something interesting is found. Another leg could have a microscope to inspect any unique rocks the rover finds. This would be an efficient use of the vehicle’s components since we’re making the parts multipurpose.

The reason why this idea was abandoned is because of the sheer number of moving components. Each leg would need at least three joints, which, with eight legs, would be a minimum of 24 joints. If even one of the joints broke down, it would be very difficult to repair in the middle of nowhere on Ceres and would slow down the entire trip. Because of the unpredictability, this idea was given up on.

3. Pogostick

This idea involves moving the vehicle through ejecting it upwards and forwards, letting it land naturally. This idea was a personal favorite because of how efficient it is. It barely consumes any fuel and leverages Ceres’ low-gravity environment to travel. But with these great advantages comes a great compromise: predictability. After launching the vehicle up, there’s not really any reliable way to change directions or choose the landing spot. If you accidentally land in a space with lots of jagged rocks, it will probably damage the vehicle and make it hard to recover. The risk that comes with not being able to steer the vehicle made this idea redundant.

Other ideas we had:

• Tank tracks
• Rolling spheres as wheels
• Track-wheel hybrid
• Drill based anchor system (Drags itself forward)

–

Prototype

After more discussion, we settled on a traditional 4 wheel car design – but with a twist. Here is a intial sketch of our prototype:

Our vehicle has two major changes that separate it from a normal car: squishy tires and overpowered suspension. These two features help tackle issues we anticipate with navigating on Ceres, mainly the rough surface. The squishy tires will mold over jagged rocks on the surface without damaging the wheels. The great suspension will allow it to drive smoothly, preventing obstacles from scraping parts of the vehicle due to how elevated the suspension makes it. Basically, it’s a monster truck on steroids.

–

What are we testing?

Our vehicle is intended to test the mobility and navigation, energy efficiency, durability and material integrity, and communication systems of crewed vehicles in extreme extraterrestrial environments.

That means experimenting with everything from how nimble it is at crossing jagged surfaces like those found on Ceres to how little energy it consumes compared to its output.

–

How will we test it?

In short, we will measure our success based on the functionality and overall efficiency of our vehicle in simulated environments.

The simulated environment means we will do our best to recreate the rough surface of Ceres, which is the main obstacle this vehicle prototype is trying to overcome. We plan to build a surface with simulated hills and rocks, which will allow us to see how much damage is done to the vehicle and how smoothly it can drive through observation. To measure energy efficiency, we will see how much distance our vehicle can cover compared to other designs. We will track this by seeing how much energy is consumed relative to the distance traveled through measuring the amount of power used by the motors in total. We can also test if the tires are efficient and if the enlarged wheel design creates extra friction that dissipates a lot of mechanical energy by seeing how efficiently potential energy from the battery converts to kinetic energy. To test the reliability of our communication system, we will measure how far we can remotely control the vehicle before it loses connection. We will do this most likely with tape measurers and distance markers, which will allow to track distance accurately down to the centimeter.

–

Mechanical Drawings and BOM

List of materials to be purchased here!

–

AI Transparency Statement

Dall-E was used to generate one image above, intended to give the reader a better idea of what our prototype might look like.

–