A single mission could orbit Pluto and explore the Kuiper Belt
By using multiple gravity assists and electric propulsion, a single mission could orbit Pluto and its moons, then continue on to conduct closeup studies of other dwarf planets and small Kuiper Belt Objects, according to a Southwest Research Institute (SwRI) study presented at a workshop of the 50th annual meeting of the American Astronomical Society (AAS) Division for Planetary Sciences (DPS) in Knoxville, TN.
Led by New Horizons principal investigator Alan Stern of SwRI, the study was funded by research grants aimed at exploring a return mission to Pluto, this time with an orbiter. While New Horizons sent back stunning images and a wealth of data about the Pluto system, its quick flyby allowed it time to image only one side of the planet in high resolution. The other side was photographed in low resolution on the spacecraft’s approach.
Data returned by the spacecraft raised a host of new questions about the Pluto system and quickly led scientists to consider a return mission with an orbiter.
Other scientists who took part in the groundbreaking study, all at SwRI include spaceflight engineer Mark Tapley, planetary scientist Amanda Zangari, project manager John Scherrer, and software lead Tiffany Finley.
A key provision of the new proposal is using gravity assists as a fuel-saving measure. New Horizons used one gravity assist from Jupiter to shorten its journey to Pluto. Similarly, an orbiter could use gravity assists from Pluto’s large moon Charon to change its orientation, allowing it to study different parts of Pluto’s surface, its atmosphere, each of its four small moons, and interactions between the system and the solar wind.
Once it arrives at Pluto, the spacecraft could enter orbit using electric propulsion, the same technology that powered NASA’s Dawn mission to Vesta and Ceres.
These methods would save fuel, enabling the orbiter to study the Pluto system for several years. After accomplishing its science objectives, the orbiter could escape the Pluto system entirely via a Charon gravity assist and head further out into the Kuiper Belt without using fuel, once again relying on electric propulsion.
According to Tapley, this technology could enable the spacecraft to enter orbit around a second, more distant dwarf planet after Pluto.
“This is groundbreaking. Previously, NASA and the planetary science community thought the next step in Kuiper Belt exploration would be to choose between ‘going deep’ in the study of Pluto and its moons or ‘going broad’ by examining smaller Kuiper Belt Objects and another dwarf planet for comparison to Pluto. The planetary science community debated which was the right next step. Our studies show you can do both in a single mission: it’s a game changer,” Stern emphasized.
Finley actually designed a hypothetical mission, relying on numerous gravity assists from Charon. “This tour is far from optimized, yet it is capable of making four or five more flybys each of Pluto’s four small moons, while examining Pluto’s polar and equatorial regions using plane changes,” she explained. “The plan also allows for an extensive close-up encounter with Charon one last time to escape into the Kuiper Belt for new assignments.”
In a separate but related study, Zangari researched potential missions to the 45 largest known Kuiper Belt Objects, including many dwarf planets, that could be done between 2025 and 2040 via gravity assists from one or more of the solar system’s gas giant planets.
Over the next several months, the SwRI team plan to explore the ideal spacecraft for a combined Pluto orbiter-Kuiper Belt exploration mission and expect to regularly publish their findings.
“Who would have thought that a single mission using already available electric propulsion engines could do all this? Now that our team has shown that the planetary science community doesn’t have to choose between a Pluto orbiter or flybys of other bodies in the Kuiper Belt but can have both, I call this combined mission the ‘gold standard’ for future Pluto and Kuiper Belt exploration,” Stern said.
Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.