A team of Italian scientists has drawn up a plan to achieve one of the most distant and enigmatic objects in our solar system: the Dwarf Planet Sedna .
Two options. Research, prepublished in Arxiv, details two concepts of spacecraft designed to drastically shorten the trip to Sedna. The goal is not only to reduce the travel time but also to arrive before the dwarf planet immerses itself in the darkness of deep space for thousands of years.
One design proposes a high-tech solar sail that could potentially make the journey in just seven years . The other concept involves a nuclear fusion rocket , which would take about ten years , but with a significant advantage: it could enter orbit around Sedna once it arrives.
The moment is key. Planet Sedna , discovered in 2003, has an incredibly eccentric orbit that lasts approximately 11,000 years . In 2076 , it will reach its perihelion, the closest point in its orbit to the Sun. Although “close” is a relative term—Sedna will be nearly 11 billion kilometers away, roughly three times the distance from Neptune to our star.
This presents a unique opportunity in millennia to send a probe. Current rocket technology would require between 20 and 30 years for such a mission, necessitating a complex and high-budget project to be developed rapidly.
The cheap alternative. The first option, the solar sail , takes advantage of solar photon thrust to propel the spacecraft. This concept has already been tested in missions like Lightsail 2 by the Planetary Society. However, this sail would further innovate by being coated with a material that, when heated by sunlight, releases molecules via a thermal desorption process, resulting in additional thrust.
Utilizing Jupiter’s gravitational assistance , this ultralight ship could reach Sedna in just seven years. The significant advantage is that it wouldn’t need to carry fuel, thus reducing overall weight. However, the downside is that it would only be able to perform a quick flyby—similar to what the New Horizons probe did with Pluto. While this would yield valuable data, the encounter would be fleeting.
The ambitious alternative. The second proposal is more ambitious: a rocket powered by a nuclear fusion engine currently being developed at the Princeton Plasma Physics Laboratory . This engine could produce both thrust and electrical energy from a controlled nuclear fusion reaction, offering continuous and powerful acceleration throughout the journey.
A trip with this nuclear engine would take about ten years . While it is slower than the solar sail, it has a major advantage: it could insert the spacecraft into Sedna’s orbit, facilitating a much more detailed long-term study of its surface, composition, and interaction with the surrounding space environment compared to the solar sail approach.
Why Sedna? The interest in Sedna is not solely due to it being a trans-Neptunian object , an icy body that orbits beyond Neptune. Its reddish surface and extreme orbit make it a pristine relic from the early formation of the solar system. Scientists theorize that Sedna may contain organic compounds and water ice , which are essentially the primordial “bricks” of planets.
Most of Sedna’s time is spent far away from the Sun, allowing its surface to remain largely untouched by radiation and heat. One of the more intriguing hypotheses posits that Sedna could be an exoplanet that was captured by our solar system during a past stellar encounter . Analyzing its composition in situ would provide an unprecedented opportunity to study material from another star system—all within our own solar system.
Image | CSWANCMU (CC)
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