In the unyielding pursuit to shorten and enhance the safety of journeys to Mars, Russian researchers have recently sparked interest with a daring assertion: A plasma-based propulsion system could decrease the Earth-Mars transit time to merely 30 to 60 days. This represents a significant reduction from the usual estimate of around 9 months to reach the Red Planet, potentially extending up to a year for crewed missions.
Plasma, or electric propulsion, is not a novel concept. For many years, spacecraft have utilized variations such as ion thrusters and Hall-effect thrusters for tasks like station-keeping, orbital maneuvers, and deep-space explorations. NASA’s Dawn mission implemented ion propulsion to investigate the asteroid belt, while several commercial communication satellites leverage electric thrusters to sustain their orbits. All these systems function by accelerating charged particles (ions) with electric or magnetic fields, providing remarkable fuel efficiency, though they produce comparatively low thrust. What distinguishes the Russian initiative is its potential to advance plasma propulsion far beyond current applications. If it proves successful, it could herald a new era in interplanetary travel, transforming plasma engines from mere orbital stabilizers into primary propulsion systems capable of traversing vast distances within the solar system.
Functionality of the new plasma engine
The researchers from the state-owned Rosatom developed a laboratory prototype of a plasma electric rocket, utilizing a magnetic plasma accelerator. Essentially, rather than combusting chemical fuel and oxidizer to generate hot gas for thrust, this engine ionizes a working fluid (hydrogen, in Rosatom’s example) into plasma (charged particles). It then harnesses electromagnetic fields to accelerate these charged particles to extremely high speeds and expel them, thereby propelling the spacecraft forward.
This configuration enables the exhaust velocity of particles to reach approximately 100 km/s (about 62 miles per second), significantly exceeding the 2 to 4.5 km/s exhaust speeds typical of chemical rockets. The prototype reportedly operates in a pulse-periodic manner with an average power of around 300 kW. The thrust is currently modest (approximately 6 newtons), which is lower than that of chemical rockets, but in plasma propulsion, the goal is to provide continuous acceleration over extended periods to gradually achieve high velocities. The Rosatom team asserts that the prototype could function for over 2,400 hours, which they consider adequate for a Mars mission according to their theoretical framework. They aim to create a flight-ready version of the engine by 2030.
In comparison to chemical rocket engines, the primary consideration is the balance between thrust and efficiency. Chemical rockets can produce exceptionally high thrust, which is essential for launch and swift maneuvers. However, they utilize propellant inefficiently and face limitations related to the chemical energy constraints of fuel-oxidizer reactions. Plasma engines, in contrast, deliver significantly greater propellant efficiency and higher exhaust velocities, making them more appropriate for prolonged, sustained acceleration in space. The Russian design will depend on conventional rockets to elevate the spacecraft into orbit, subsequently transitioning to the plasma engine for the Mars journey phase.
Traveling to Mars now and in the future
Achieving Mars in 30 to 60 days would necessitate average speeds much higher than what current spacecraft can manage. Presently, missions to Mars require up to 9 months on average, depending on planetary alignment, fuel limitations, and orbital transfer tactics. Key challenges include limited thrust, the inefficiencies linked with chemical propulsion, and the hazards faced by astronauts from cosmic radiation during prolonged exposure.
NASA’s Deep Space 1 mission, launched in 1998, utilized ion propulsion to attain a specific impulse (a gauge of thrust efficiency) of 3,100 seconds. This is roughly ten times greater than that of chemical rockets. This efficiency emphasizes the significance of plasma engines for the future of deep-space exploration. In 2023, NASA employed Hall-effect thrusters to travel to the metal-rich asteroid Psyche. This mission is projected to arrive at its target in 2029, demonstrating the viability of electric propulsion for extended space travel.
Building on this progress, a new Russian plasma engine promises even greater efficiency and sustained thrust, potentially facilitating much shorter travel durations to Mars and beyond. If successful, such technology could signify a pivotal moment in deep-space propulsion, enabling faster, more ambitious missions throughout our solar system.
