Insights from Martian Conditions for Hyperloop Pressure Management

This past week, our depressurization research team focused on the electronics aspect of how to control our pressure in case of any accidents. Whether it was looking at specific sensors that could detect even the most minute changes, or finding if Raspberry Pis worked in low-pressure environments, I thought it would be interesting to research a specific case study where people have controlled their own pressurized environment. I specifically focused on a paper, Hypobaric Chamber for Wind Sensor Testing in Martian Conditions, that researched the Marslab-UPC hypobaric chamber, a pressurized chamber made to replicate conditions on Mars. I was particularly interested in how the lab had handled pressure management, which is similarly what we are looking into right now.

The first thing that stood out to me was how simple their vacuum chamber setup was. The lab used a stainless steel chamber and a standard wind tunnel, but what made it impressive was the level of control achieved through thoughtful engineering. Every valve, gauge, and sensor was placed deliberately to ensure the system could maintain stability despite rapid pressure shifts. Additionally, there is the pumping system that the lab uses. At first, they used solely a rotary pump, which wasn’t effective until they added a roots pump. The roots pump was used to reduce the system's pressure to 0.001 mBar, making the pressure in the chamber significantly lower than what the rotary pump could have achieved. The rotary pump took most of the work, whereas the roots pump allowed the system to reach such low pressures. It reminded me of how our system is only going to be successful by layering multiple different technologies.

Another aspect I found really interesting was the cycle time of bringing the system back to atmospheric pressure. For the small MARSLab Chamber, it took around 17 minutes to bring the system down to low pressure and fill it up with normal air. Although 17 minutes sounds like a short amount of time, in the scenario of the vacuum chamber breaking, our team would be working with less than one second to bring the system back to normal pressure while keeping the health and safety of all of our passengers. By decreasing the time used to bring the system to normal pressure, we would be compromising the structure and the safety of the Hyperloop (and the people inside). By reading into this case study, I was able to gain insight into how a highly controlled system like the MARSLab was able to control its pressure, but also learn that the reaction time needed for our project needs to be smaller than expected.

One of the things the lab did that I thought was interesting was how they used the Reynolds number and adjusted it to recreate aerodynamic conditions. The Reynolds number is a standard ratio that compares inertial forces to viscous forces in a fluid, and this ratio is used in predicting liquid flow patterns in different environments, like a vacuum chamber or Mars, in this case. They showed that by tweaking pressure and velocity, you could test airflow under Martian-like situations right here on Earth. It would be interesting to use that same equation to help us predict how air would behave inside the tube during a rapid depressurization.

In terms of preventing depressurization, we have started the process of designing a sensor network to first detect last-minute pressure changes. From there, it would be interesting to explore how multi-stage pumping systems would help prevent/mitigate the effects of depressurization. It would also be interesting to see if we can use the sensors to anticipate a pressure drop, and by that point the pumping system would be able to pump in extra air or adjust the valves to stabilize the system before anything actually happens. By better understanding different cases in which pressure plays a role in a vacuum, we can take their findings to help advance our current depressurization research.