Mission:
My friends and I are tasked to find an optimal planet/asteroid/moon to be our new home, research about it’s environment, and design a vehicle to be used on said destination that can travel back and forth 5km. This post will be focused on defining our problem and researching the background of our destination.
Our chosen destination? Ceres.
Definition Statement: 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.
Background:
Ceres was first discovered by astronomer Giuseppe Piazzi on the first of January, 1801 from the Palermo Observatory in Italy. However, after Piazzi fell ill, Ceres was lost and remained undiscovered until almost a year later, when Carl Frederich Gauss took it upon himself to help rediscover Ceres.
Gauss used his very own least squares method, a statistical approach where he used data from Piazzi’s previous viewings of Ceres to find the best fitting curve to predict where Ceres’ current location was. He assumed that Ceres too had an eliptical orbit within the solar system, adopting Kepler’s laws of planetary motion. This image on the left is a depiction of what Gauss’ preliminary data may have looked like.
Gauss used a method called iterative refinement. As the name implies, this method repeats itself over many iterations to refine itself into a near-perfect line/curve similar to the image on the right. After over 100 hours of hard work, Gauss had finished his masterpiece.
Gauss’ contributions helped rediscover Ceres and with the rediscovery came an even more accurate orbital based on more observations. In addition, previous observations of Ceres were only made by Piazzi, so there was a margin of error in play and the increase number of astronomers viewing Ceres after it’s rediscovery helped lower that margin.
That data collected due to Gauss’ contributions include Ceres’ 4 degree axial tilt, 9 hour rotations, and 4.6 earth year solar orbit.
Ceres is located between Mars and Jupiter in our solar system in the asteroid belt and is the largest known object there. Ceres is currently classified as a dwarf planet and it’s mass contributes 25% to the overall mass of the asteroid belt. Additionally, Ceres’ radius is approximately 1/13th that of Earth’s and 1/4th of the Moon’s.
Ceres is similar to other planets such as Earth in that it’s surfaces are layered. Ceres likely has a solid core and a mantle made out of water ice. Chunks of ice and dirt are in abundance on the surface, and it’s fairly dusty as well.
Why Ceres?
We chose Ceres because it was a planet with low gravity and very low air density which could the reduce the restriction of being energy efficient, as outlined in our definition statement. Although Ceres has temperatures that can go below -105°C, other alternatives aren’t much better.
Due to Ceres’ placement within the solar system, Ceres is the most optimal research hub for asteroids since it’s the only dwarf planet in the asteroid belt and is right next to the closest cluster of asteroids near Earth. Additionally, NASA’s very own Dawn discovered deposits of salts on Ceres’ surface. These deposits are believed to be the remnants of evaporated water, indicating the presence of water underneath it’s surface.
As it turns out, just 25 miles below Ceres’ Occator Crater, researchers found that there could be a water reservoir that stretches hundreds of miles wide. The crater’s brightness is due to the density of salt on the surface.
Using infrared spectroscopy, NASA’s Dawn orbiter using it’s VIR (Visual and Infrared Imaging Spectrometer) detected the electromagnetic wavelengths (measured in µm on this graph) and measured the levels of reflection of each wavelength from Ceres. As you can see, the Occator Crater showed a significant decrease in spectral reflectiveness from 3.1-3.5 µm (measured in the ratio reflected light to incident light such as light from the sun).
In this range, water ice has strong absorption features, which lower the I/F, along with hydroxyl-bearing materials. Minerals with hydroxyl are known to be a byproduct of water altering minerals over time. This shows indirect evidence of water being on Ceres’ surface for a prolonged period of time.
This discovery is a clear sign that Ceres may have been habitable- and might still be.
Challenges/Limitations
The main challenge that we will have to face on Ceres is the rocky terrain which is much bigger of a problem when combined with the gravity on Ceres. Ceres has approximately 3% of Earth’s gravity so we will need to find a method of transportation that will either lock us onto the ground or be some sort of other alternative like an aerial based vehicle.
Unfortunately, Ceres’ low air density will make it so that any aerial-based vehicles will have way less lift than usual.
The lift equation where L is lift, p is air density, v is velocity, s is wing area, and CL is the coefficient of lift is a good example of how this could go wrong.
Due to the lower amount of air density, it will be very hard to generate lift even through upward thrust because to put it simply- there is no lift to push against. This almost completely eliminates aerial-based vehicles unless we find a breakthrough alternative. Adding on, keeping a constant upward thrust with 3 crew members inside the vehicle while also going forward may not be so energy-efficient.
Ceres’ mantle is made of solid ice so we can’t travel by water so we’re pretty much limited to a ground-based vehicle for now.
Another big challenge would be safety. The harsh climate of Ceres would mean that we would need a vehicle that can protect us from the constant changes of temperature and radiation from the sun due to the lack of an atmosphere. Extra features such as emergency/escape systems will also be a must, along with keeping the inside fully sealed and pressurised, again, due to the lack of an atmosphere.
Due to the dusty and rocky terrain of Ceres we will also need a way to stop the dust/rocks from wearing down the vehicle over time or malfunctioning the machinery. The machinery will also need some sort of way to be rechargeable since our mission is to make Ceres our new home.
Another huge challenge that we will have to face is finding the necessary fuel to power our vehicle. However, it’s most likely that whatever energy we use will need to be converted into mechanical energy since it’s the most conventional way of powering a moving vehicle. Like I mentioned previously, water ice has the formula H2O and through some sort of decomposition, we might be able to use liquid hydrogen and liquid oxygen to use as rocket fuel since these 2 elements are conventionally used as such.
Safety is another issue, but that can be easily solved with good preparation and the right equipment.
Since this post is mainly about empathising with the target audience (our crew) and starting to come up with ideas for the problem statement, it would make sense to keep actual decisions for another time as we aren’t 100% sure of anything yet and that will be decided once we finish our first prototype.
No AI was used to write this blog post.
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