【】The beginnings of the solar system

Two new missions selected by NASA Wednesday will help scientists understand the beginnings of our solar system.。

The missions -- called Lucy and Psyche and expected to launch in 2021 and 2023, respectively -- will send robotic spacecraft to asteroids thought to be leftovers from the dawn of planet formation billions of years ago.。

“Lucy will visit a target-rich environment of Jupiter’s mysterious Trojan asteroids, while Psyche will study a unique metal asteroid that’s never been visited before,” said Thomas Zurbuchen, associate administrator for NASA’s science mission directorate, in a statement.。

A very metal asteroid。

Psyche's target -- the asteroid 16 Psyche -- is thought to be a 130-mile-wide, metal-rich asteroid that might somewhat resemble Earth's core, according to NASA.。

Researchers have even suggested that the asteroid is actually the leftover core of a doomed Mars-sized planet that "lost its rocky outer layers" when a number of impactors slammed into it billions of years in the past, NASA added.。

The asteroid is also metal as hell ... literally.。

“This is an opportunity to explore a new type of world -- not one of rock or ice, but of metal,” Psyche principal investigator Lindy Elkins-Tanton said in the statement.。

“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.”

It won't be a short journey for NASA. The asteroid is located nearly 300 million miles from the sun.。

The beginnings of the solar system。

The Lucy mission, for its part, is going to be zipping around the solar system after its launch in 2021.。

Instead of staring deeply at one target, Lucy is designed to study a number of space rocks. The mission will visit one asteroid in the main belt between Mars and Jupiter and six Trojan asteroids -- rocky bodies trapped in two groups by Jupiter's gravity -- from 2025 to 2033, NASA said.
。

Lucy will make a stop at its main belt target in 2025 and then start studying its first Trojan asteroid in 2027, eventually ending its mission in 2033. 。

“This is a unique opportunity,” said Harold Levison, principal investigator of the Lucy mission, said in the statement.。

“Because the Trojans are remnants of the primordial material that formed the outer planets, they hold vital clues to deciphering the history of the solar system. Lucy, like the human fossil for which it is named, will revolutionize the understanding of our origins.”

The chosen few。

The two asteroid missions were chosen from five Discovery program finalists announced in 2015, beating out two missions that would have sent spacecraft to Venus and another asteroid probe.。

The other asteroid mission, called NEOCAM, didn't totally miss out, however. That spacecraft -- which is designed to hunt for potentially hazardous objects like asteroids near Earth -- will be funded for development for the next year by NASA. 。

Under the parameters of the program, Psyche and Lucy should not exceed $450 million in cost of development. 。

For perspective, that's on the low end of the cost spectrum for a NASA mission. Many of the space agency's flagship missions cost more than $1 billion.
。

NASA's Messenger mission to Mercury and the alien planet-hunting Kepler Space Telescope were both funded and launched under the agency's Discovery program as well.。

最新评论