Engineers and researchers around the world have been putting significant effort into making satellites smaller. Smaller satellites cost less to develop and cost less to put into orbit. The trick is creating a small satellite that can serve a useful purpose once it’s in space. Engineers from the University of Michigan built a satellite that was set to head into orbit over the weekend specifically to explore the feasibility of a new propulsion method that could help small satellites move around Earth’s orbit without carrying fuel.
If the propulsion method works, it could allow tiny cubesat satellites to stay in orbit for long periods and operate in swarms allowing them to perform functions such as monitoring storms and natural disasters. Small cubesats roughly the size of a loaf of bread, and their smaller stature allows them to hitch a ride in the space with larger missions. Traditional cubesats are low cost and allow the testing of new technology in orbit.
The cubesat developed by the engineering team is called MiTEE and was scheduled to launch Sunday from the Mojave Air and Space Port aboard the Virgin Orbit Launch Demo 2. Small satellites are affected by drag in the upper atmosphere more so than large satellites. The drag slows the orbit of small satellites and causes them to drop towards the Earth.
For that reason, smaller satellites don’t last long, with their lifespan is typically measured in days, weeks, or a few months. Small satellites are unable to oppose the drag because their size doesn’t allow additional weight for carrying propulsion systems. The engineering team is attempting to harness the laws of electromagnetism to help keep small satellites in space.
The idea is to tether two small satellites with a wire 10 to 30 meters long that can drive a current in either direction using power from onboard solar panels. The Earth’s ionosphere would close the electrical circuit. When the wire conducts a current in a magnetic field, the magnetic field exerts a force on the wire. The engineering team hopes to use the force of the Earth’s magnetic field to push the satellite higher in orbit and compensate for the atmosphere’s drag.
The satellite has a deployable rigid boom that is one meter long between one small satellite about the size of a breadbox in another that’s about the size of a large smartphone. Researchers will measure how much current can be drawn from the ionosphere under different conditions. Data gathered during the mission will be used to create future satellites with a longer tether in the area of 30 feet or more.