A new plasma engine design developed by Francesco Romano as part of his Ph.D. thesis at the University of Stuttgart could revolutionize how satellites stay in orbit. The engine uses thin air as fuel, which is a major departure from traditional systems that rely on costly gases like xenon. This innovation is part of a class of propulsion technologies known as atmosphere-breathing electric propulsion (ABEP), which aim to sustain satellites in very low Earth orbit (VLEO), where atmospheric drag is strongest. VLEO ranges from 100 to 450 kilometers (62 to 280 miles) above the Earth's surface, and maintaining a stable orbit in this region requires continuous propulsion. The engine works by drawing in air molecules from the upper atmosphere, converting them into plasma using an electric field, and then expelling the plasma to generate thrust. However, this process faces significant challenges. The upper atmosphere contains atomic oxygen (AO), a highly reactive molecule that can corrode parts of the propulsion system. AO also poses a risk to the cathodes used in the "electron gun" that neutralizes the spacecraft to prevent it from becoming electrically charged, which could interfere with the propulsion system's effectiveness. To tackle these issues, Romano designed a radio-frequency (RF) helicon plasma thruster that doesn't require a neutralizer, inspired by medical devices like MRI machines. The thruster uses a birdcage-like antenna to efficiently channel electrical power into the system. Additionally, he developed an optimized intake system to collect air particles more effectively. In wind tunnel tests, a "specular intake" design, resembling a parabolic mirror coated with graphite or silicon dioxide, proved most efficient, capturing about 94.3% of air particles. The design showed only an 8% drop in efficiency when tilted by 15 degrees. Romano's engine design could operate indefinitely at altitudes between 190–250 km (118–155 miles) using less than 1.6 kW of power, which is well within the capabilities of standard spacecraft solar panels. This could allow satellites to stay in orbit much longer without refueling. The design also shows promise for future missions around Mars, where it could support spacecraft at altitudes of 120–160 km (75–99 miles), much closer than current satellites. While it is unclear whether Romano plans to commercialize or test the engine in actual missions, the design represents a significant advancement in sustainable space propulsion.