Science and Exploration

NASA Selects Two Discovery Missions to Explore Solar System History

By Keith Cowing
Press Release
January 5, 2017
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NASA Selects Two Discovery Missions to Explore Solar System History
Psyche Spacecraft

ASA selected two missions to explore the earliest history of our solar system, a time less than 10 million years after the birth of our Sun.
The Discovery missions Psyche and Lucy were selected from five finalists, and will each cost approximately $450 million to develop.

The Near Earth Object Camera (NEOCam) proposal, which would discover 10 times more near-Earth objects than all discovered to date, was given extended funding for an additional year by NASA. Planetary Science Institutes’ Mark Sykes and Tommy Grav are part of NEOCam.

Psyche will help scientists understand how planets and other bodies separated into layers – including cores, mantles and crusts – early in their histories.

Planetary Science Institute Senior Scientist Thomas H. Prettyman is a Co-Investigator on the Psyche mission, where he is a member of the Gamma Ray and Neutron Spectrometer (GRNS) team. The data acquired by the GRNS at Psyche will be analyzed to determine surface elemental composition, providing constraints on planetary evolution and core formation.

“This is an opportunity to explore a new type of world – not one of rock or ice, but of metal,” said Psyche Principal Investigator Lindy Elkins-Tanton of Arizona State University in Tempe. “16 Psyche is the only known object of its kind in the Solar System, and this is the only way humans will ever visit a core. We learn about inner space by visiting outer space.”

The Psyche mission will explore the origin of planetary cores by studying the metallic asteroid 16 Psyche, one of the most intriguing targets in the main asteroid belt, located about three times farther way from the Sun than is the Earth. The asteroid measures about 130 miles in diameter and is thought to be comprised mostly of metallic iron and nickel, similar to Earth’s core. This asteroid is likely a survivor of a violent hit-and-run with another object that stripped off the outer, rocky layers of a protoplanet.

“Psyche is thought to be the exposed core of a planetary embryo – perhaps like Vesta – that initially melted and later cooled to form a central metallic core, silicate mantle, and basaltic crust. The outer layers may have been removed in a violent collision, leaving the core exposed,” Prettyman said. “Psyche will provide a close-up look at a planetary core, providing new insights into the evolution and inner workings of terrestrial planets.”

Psyche, a robotic mission, is targeted to launch in October of 2023, arriving at the asteroid in 2030, following an Earth gravity assist spacecraft maneuver in 2024 and a Mars flyby in 2025.

Visit for an image of a model of the Psyche spacecraft.

“Selecting two proposals is an important first step towards rebuilding the critical Discovery program,” said PSI CEO and Director Mark Sykes. “Ten of the 12 previous selections were made more than 15 years ago, and those missions have largely come to an end. A renewed investment in these lower cost, competed missions is great news for American Solar System exploration.”

“It is good news that NEOCam continues to be supported for an additional year,” Sykes said. “It is necessary to satisfy the Congressional mandate to find 90 percent of NEOs 140 meters or greater, that may threaten the Earth. It is has also been identified as essential to future human exploration activities, identifying potential resource targets in accessible orbits and human mission targets that allow for quick round-trip missions – avoiding the radiation load issue. Hopefully, resources will be identified this year to fund NEOCam and support these important objectives.”

Lucy, the other Discovery mission selected, will visit the target-rich environment of Jupiter’s mysterious Trojan asteroids. The robotic spacecraft is slated to launch in 2021.

Created in 1992, NASA’s Discovery Program sponsors cost-capped Solar System exploration missions with highly focused scientific goals. The program has funded and developed 12 missions to date, including MESSENGER, Dawn, Stardus, Deep Impact, Genesis and Grail, as well as InSight, slated to launch for Mars in 2018.

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