Italian researchers have proposed two revolutionary concepts that could deliver a probe to the dwarf planet Sedna in just one decade — instead of the traditional 30–40 years. In a new preprint, the team examined the Direct Fusion Drive (DFD) thermonuclear engine and an ultra-lightweight solar sail enhanced by the thermal desorption effect.
Sedna, discovered in 2003 on the edge of the Kuiper Belt, completes one full orbit around the Sun in approximately 10,000 years. Its next perihelion will occur in 2075–2076, when the distance to the sun will decrease to “only” 11 billion km. The authors of the study calculated that this would be the most favorable launch window: the DFD probe could reach the planetoid in about 10 years, and the solar sail in a record 7 years, cutting the travel time by more than half compared to chemical rockets.
Direct Fusion Drive is based on the D-³He reaction and simultaneously generates thrust and electrical power (~1.6 MW). Continuous acceleration allows not only to fly by, but also to brake to enter Sedna’s orbit, which is critically important for long-term observations and delivery of a 50-kilogram scientific payload.
Solar sail (area of several hundred square meters) will receive additional momentum when a special coating evaporates molecules under the heat of the Sun. Combined with a gravity assist maneuver at Jupiter, this gives an average speed of >20 km/s, but only enables a high-speed flyby of Sedna and data transmission during the approach.
The quick mission to Sedna opens a “window” into the early history of the Solar System: ice, organic matter, and isotopes on the surface of the dwarf planet preserve the chemical composition of the protosolar nebula. Testing DFD and large sails will bring humanity closer to the Kuiper Belt and even objects in the Oort Cloud, as well as providing new platforms for deep space astrophysical instruments — from ultraviolet spectrographs to radio interferometers with a base extending beyond Pluto’s orbit.
If you are fascinated by the journey to the icy edges of the Solar System, the next step is to understand the extreme temperatures that exist in space and why even sunlight does not always protect against the extreme cold. Read our article “How cold is space?” to find out how cold it can be outside Earth’s atmosphere, why the Moon is both hot and cold at the same time, and how these conditions affect future missions to distant worlds.
