NASA may send smallsat mission to giant asteroid Pallas

Pallas, third largest asteroid in the asteroid belt and the second such object to be discovered, by the German astronomer and physician Wilhelm Olbers on March 28, 1802. The asteroid was named after Pallas Athena, the Greek goddess of wisdom.

Pallas is 512 kilometers (318 miles) in diameter, somewhat smaller than 4 Vesta. It is likely a remnant protoplanet. The asteroid’s orbit is unusually high in inclination to the plane of the asteroid belt, and its eccentric orbit is nearly as large as that of Pluto, making Pallas almost inaccessible to spacecraft.

NASA won’t make the final decision on funding this mission until mid-April. The so-called Athena mission will be competing with 11 other SmallSat and CubeSat mission proposals, according to Arizona State University planetary scientist Joseph O’Rourke, Athena’s principal investigator, reports Forbes.

If the mission is approved, it will follow in the path of the Dawn Mission that explored two other giant objects in the asteroid belt, Vesta and Ceres. The Dawn Mission ended last year.

Shadowy outlines of the terrain in Vesta’s northern region are visible in this image from NASA’s Dawn spacecraft. The image comes from the last sequence of images Dawn obtained of the giant asteroid Vesta as it departed the giant asteroid. The view looks down at Vesta’s north pole, which is in the middle of the image.

NASA

“Pallas is really the only other object in the main asteroid belt that’s like Vesta and Ceres … not just an asteroid, but a protoplanet, a real world,” said O’Rourke, reports Space.com. “I see this as a way to go do a lot of the same science that Dawn did, but at a dramatically cheaper price, and Pallas is the sort of place that might be worth sending a much bigger mission to someday.”

Athena would hitch a ride with Psyche Mission
If selected, Athena would launch in August 2022, riding piggyback along with the NASA Psyche Mission. Psyche is a very interesting mission in its own right. It will explore the origin of planetary cores by studying the metallic asteroid,16 Psyche. 16 Psyche is the heaviest known M-type asteroid and is thought to be the exposed iron core of a protoplanet.

This artist’s-concept illustration depicts the spacecraft of NASA’s Psyche mission near the mission’s target, the metal asteroid Psyche. The artwork was created in May 2017 to show the five-panel solar arrays planned for the spacecraft. Photo ID: PIA21499.

NASA/JPL-Caltech/Arizona State Univ./Space Systems Loral/Peter Rubin

“We would race Psyche to Mars, use Mars as a gravity assist, and then catch Pallas,” O’Rourke said. The Pallas flyby would come about a year after the launch.

Psyche is one of the ten most massive asteroids in the asteroid belt. It is over 200 kilometers (120 miles) in diameter and contains a little less than 1 percent of the mass of the entire asteroid belt.

A protoplanet is a large planetary embryo that originated within a protoplanetary disc and has undergone internal melting to produce a differentiated interior. Vesta is also a protoplanet. On January 4, 2017, the Psyche mission was chosen along with the Lucy mission as NASA’s next Discovery-class missions.