from the dogged-determination dept.
Scientists, including New Horizons principal investigator Alan Stern, met in Houston on April 24th to discuss the possibility of a Pluto orbiter mission. The mission would likely cost $1-2 billion, compared to around $700 million for New Horizons and $467 million for the Dawn mission to Vesta and Ceres. A launch date in the late 2020s is possible, with a 2030 launch coinciding with the 100th anniversary of Pluto's discovery:
[A] Pluto orbiter mission is a long way from becoming reality, Stern stressed. He said he and his fellow researchers aim to mature the concept in time for it to be considered during the next Planetary Science Decadal Survey, a U.S. National Research Council effort that sets exploration priorities for NASA every 10 years. The next decadal survey will start in 2020, finish in 2022 and be published in 2023, Stern said.
Using the Space Launch System (SLS) could reduce travel time compared to the nine-and-half-year journey of New Horizons, but braking would be required to orbit the Pluto-Charon system, increasing the total travel time back to around seven to nine years. Other missions being considered include flybys of more distant Kuiper Belt dwarf planets (Eris, Sedna, etc.) and exploration of Neptune's moons Triton and Nereid, which are likely captured Kuiper Belt Objects. Triton has about a 14% larger radius and 64% more mass than Pluto. Voyager 2 observed 40% of Triton's surface in 1989.
Astronomers are still hoping for another mission to Pluto, or perhaps another Kuiper belt object:
A grassroots movement seeks to build momentum for a second NASA mission to the outer solar system, a generation after a similar effort helped give rise to the first one. That first mission, of course, was New Horizons, which in July 2015 performed the first-ever flyby of Pluto and is currently cruising toward a January 2019 close encounter with a small object known as 2014 MU69.
[...] Nearly three dozen scientists have drafted letters in support of a potential return mission to Pluto or to another destination in the Kuiper Belt, the ring of icy bodies beyond Neptune's orbit, Singer told Space.com. These letters have been sent to NASA planetary science chief Jim Green, as well as to the chairs of several committees that advise the agency, she added. "We need the community to realize that people are interested," Singer said. "We need the community to realize that there are important, unmet goals. And we need the community to realize that this should have a spot somewhere in the Decadal Survey." That would be the Planetary Science Decadal Survey, a report published by the National Academy of Sciences that lays out the nation's top exploration priorities for the coming decade.
New Horizons 2 was already cancelled due to a shortage of plutonium-238, which still reportedly persists. One proposed target was 47171 Lempo, a trinary system. The trans-Neptunian dwarf planets Eris, Haumea, Sedna, Orcus, Salacia, Makemake, and 2007 OR10 (the largest known body in the solar system without a name - with an estimated 1,535 km diameter) have all been discovered since 2002. Several of these TNOs have moons and Haumea was recently found to have a ring system.
Now that Cassini is dead, most new NASA missions are focused on Mars and Jupiter, leaving the solar system's "ice giants" relatively unstudied: