Universe Today
It's a New Year, with new challenges and new opportunities! And NASA, looking to kick things off, has announced the two new missions that will be launching in the coming decade. These robotic missions, named
Lucy
and
Psyche,
are intended to help us understand the history of the early Solar System, and will deploy starting in 2021 and 2023, respectively.
While Lucy's mission is to explore one of Jupiter's Trojan asteroids, Psyche will explore a metal asteroid known as 16 Psyche. And between the two of them, it is hoped that they will answer some enduring questions about planetary formation and how the Solar System came to be. More than that, these mission represent historic firsts for NASA and human space exploration.
NASA's Discovery Program
, of which Lucy and Psyche are part, was created in 1992 to compliment their larger "flagship" programs. By bringing scientists and engineers together to design missions, t
he Discovery Program's focus has been to maximize scientific research by creating many smaller missions that have shorter development periods and require less in the way of operational resources.
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Artist's concept of the Lucy spacecraft flying by Eurybates, one of the six diverse and scientifically important Trojans it will study. Credit: SwRI
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The Lucy mission is scheduled to launch in October of 2021, and is expected to arrive at its first destination (a Main Belt asteroid) in 2025. It will then set course for Jupiter's Trojans, a group of asteroids that are trapped by Jupiter's gravity and share its orbit. These asteroids are thought to be relics of the early Solar System; and between 2027 and 2033, Lucy will study six of them.
In addition to being the first mission to explore Jupiter's Trojan population, Lucy is also of historic importance because of the number of asteroids it will visit. Throughout the course of its mission, it is will investigate six Trojans, which is the total number of Main Belt asteroids that have been studied to date. The nature of these six asteroids is also expected to tell us much about the early history of the Solar System.
As Harold F. Levison - the principal investigator of the Lucy mission from the Southwest Research Institute (SwRI) in Boulder, Colorado - explained during a NASA call-in briefing:
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Illustration of the Lucy spacecraft's orbit around Jupiter, which will allow it to study its Trojan population. Credit: SwRI
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The six Trojans that Lucy is intended investigate were selected because the diversity of their physical characteristics show that they are from different locations throughout the Solar System. As Levison put it, "These small bodies really are the fossils of planet formation, and that's why we named Lucy after the human ancestor known as Lucy."
In addition, Lucy will build on the success of missions like
New Horizons
and
OSIRIS-REx
., which includes using updated versions of instruments they used to explore Pluto, the Kuiper Belt, and the asteroid Bennu -i.e. the
RALPH and LORRI instruments
and the
OTES instrument
. In addition, several members of the New Horizons and OSIRIS-REx science teams will be lending their expertise to the Lucy mission.
Similarly, the Psyche mission will of be immense scientific value since it will visit the only metal asteroid known to exist. This asteroid measures about 210 km (130 mi) in diameter and is believed to be composed entirely of iron and nickel. In this respect, it is similar to Earth's metallic core, as well as the cores of every terrestrial planet in the Solar System.
It is for this reason why scientists believe it may be the exposed core of a Mars-sized planet. According to this theory, 16 Psyche experienced several major collisions during the early history of the Solar System, which caused it to shed its rocky mantle. The robotic probe will launch in 2023 and is expected to arrive by 2030 - after receiving an Earth gravity-assist maneuver in 2024 and a Mars flyby in 2025.
By measuring its composition, magnetic field, and mapping its surface features, Lucy's science team hopes to learn more about the history of planetary formation. As Lindy Elkins-Tanton - the Principal Investigator of Psyche and the Director of the
School of Earth and Space Exploration
at Arizona State University - said during the NASA call-in briefing:
Not only are planetary cores thought to be where magnetic fields originate (which are necessary for the emergence of life), but they are entirely inaccessible to us. The very edge of Earth's outer core is roughly 2,890 km (1790 mi) from our planet's surface. But the deepest humanity has ever dug has been to a depth of 12 km (7.5 mi), which took place at the
Kola Superdeep Borehole, in Russia.
In addition, within the Earth's core, temperature and pressure conditions are estimated to reach 5700 K (5400 °C; 9752 °F) and 330 to 360 gigapascals (over three million times normal air pressure). This makes exploring the core of our planet (or any other planet in the Solar System, for that matter) completely impractical. Hence why a robotic mission to a world like Pysche is such an opportunity.
And since Psyche is the only rounded body of metal that is known to exist in the Solar System, the asteroid is as improbably as it is unique. And since no missions have ever taken place to explore its surface, and no pictures exist that can tell us what its surface features would look like, the Psyche mission is sure to shed some serious light on what a metal world looks like.
"What do we think it might look like?" asked Tanton. "Does it have surface sulfur lava flows on its surface? Is it covered with towering cliffs created when solidifying metal shrank and the exterior of the body broke into fault? Is its surface a combination of iron metal and green mineral crystal as iron meteorites are? And what does an impact crater in metal look like? Could its edges or its metal flashes become frozen in the cold of space before they fell back on the surface. We don't know."
Jim Green, NASA's Planetary Science Director, expressed enthusiasm for the Discovery 13 and 14 missions in a recent NASA
press release
:
Lucy and Psyche were chosen from five finalists that were selected for further development back in September 2015. These in turn were chosen from 27 mission concepts that were submitted back in November of 2014. Examples of past and present Discovery missions include the
Kepler space probe
, the
Dawn spacecraft
, the
Mars Pathfinder
, and the
InSight lander
(which is scheduled to launch in 2018).
Further Reading: NASA