NASA’s Trojan Asteroid Mission Suffers a Setback: Here’s How Engineers Are Trying to Fix It

NASA’s Lucy mission, scheduled to explore a group of asteroids that follow behind and ahead of Jupiter’s orbit, ran into a problem recently when one of its solar panels failed to deploy. On Thursday, Lucy’s team announced that it would perform two maneuvers to fully deploy its solar panels.

The Lucy mission will study leftover crumbs from the early Solar System and needs to get to Jupiter’s orbit, where two gravitational rifts have picked them up. Operating farther from the Sun requires large solar panels to capture diminishing sunlight for energy, so Lucy was equipped with two peeper-like solar wings.

Shortly after its launch in October 2021, NASA officials noticed that something was wrong with one of the solar panels. His readings were unusual, and staff soon realized that the cord around a solar panel had not fully retracted, preventing sunlight from reaching the panels. An engineering model suggests that upon retraction, “the lanyard may not have wound onto the spool as intended,” NASA reported a month after launch.

According to NASA officials, the faulty array is between 75 and 95 percent deployed.

The space agency has been monitoring the situation for the past half year and on April 18 they decided on a future plan that they hope will solve the problem.

They will take two steps in the coming months to see if the solar array can be fully implemented.

The first will occur on May 9, when they will try to wind up part of the cord in a quick maneuver. The team anticipates that this one operation alone will not be enough, so they are planning a second array deployment task for a month later, which will hopefully successfully engage the solar array. The month between each task will give the teams time to analyze the best way to perform the second maneuver.

“The solar array was designed with a primary and backup motor winding to provide an additional layer of reliability for mission critical solar array deployment. Lucy’s engineers will take advantage of this redundancy by using both motors simultaneously to generate higher torque than was used on launch day. Tests on the ground show that this additional torque may be enough to pull the entangled lanyard the remaining distance needed to engage it,” NASA officials shared in a mission update released last Thursday.

So far, the issue hasn’t affected the mission too much. “That solar array is generating almost the expected power compared to the fully deployed wing. This level of power is enough to keep the spacecraft healthy and operating,” NASA officials shared three days after launch.

Having fully charged batteries is important. Lucy is headed for Jupiter at a speed of about 67,000 mph (108,000 kph) to study Trojan asteroids, peculiar rocks significantly different from those found between the orbits of Mars and Jupiter in the asteroid belt.

Trojans are leftover pieces from the formation of the Solar System that were placed in Jupiter’s orbit and thus avoided being ejected into deep space. The Trojans are trapped in two gravitationally stable points called Lagrange Point 4 and Lagrange Point 5, created by the interaction of the Sun and Jupiter.

Lucy will study seven asteroids for 12 years, so having fully functioning batteries will be essential. The team also hopes that if the cord cannot be retracted and the solar panel has to remain as it is, the main motor burns will not affect the solar panel.

Lucy will reach her first target in 2025, an object in the asteroid belt named Donaldjohanson. After its encounter with that asteroid, the ship will continue on to the group of Trojans residing in front of Jupiter, aiming to arrive in 2027. After that, a maneuver will bring it back to the inner Solar System to use Earth for assistance. gravity in 2031, only to return for a second Trojan voyage in 2033 to the asteroids that follow.

The mission is named after the three-million-year-old hominid fossil discovered in Ethiopia in 1974. Donaldjohanson is named after Lucy’s discoverer. “Lucy” is both an homage to origins science and likely a nod to the Beatles song that inspired the fossil’s name, “Lucy in the Sky with Diamonds.” Hal Levison, principal investigator for Lucy, has previously likened Trojans to jewels for their “immense scientific value.”