NASA suspends Lucy solar array deployment

NASA is suspending efforts to fully deploy a solar array aboard the Lucy spacecraft, at least until late next year, citing diminishing returns as the spacecraft moves away from the Sun. In a statement posted on NASA’s website Jan. 19, the agency said that the latest attempt more than a month ago to lock one of the two solar panels on Lucy had not completed the circular system’s deployment and locked it in place. This interference “caused only a small movement of the solar array,” according to NASA.

The mission is working on full solar panel deployment shortly after launch in October 2021. While one of the 7.3 meter diameter arrays opened and locked in place as desired, the other did not. Engineers spent months diagnosing the problem and concluded that the loss of tension in the cord used to insert the array was preventing the array from fully deploying and locking into place.

NASA downplayed the problem, stating that engineers believed the array was almost fully deployed and appeared stable. This was based on the array’s characteristics during its gravitational flight, which on October 16, less than 400 kilometers above Earth, passed smoothly through the thin upper atmosphere.

However, after this transition, the spacecraft controllers attempted to complete the deployment of the array and lock it in place. “It gradually opened the wing forward,” NASA said in a Nov. 7 trial, but the controllers also noticed a slight vibration in the system, which engineers concluded was the result of interactions between the engine and the system’s structural modes.

After adjusting the engine, NASA tried again on Dec. 13, but noticing that progress was “minimal”, engineers concluded that this was due to a drop in temperature as Lucy moved away from the sun.

“NASA’s Lucy mission team has decided to suspend further solar panel deployments,” the agency said in a recent statement. Said. “The team has determined that operating the solar panel mission in the current unlocked state carries an acceptable level of risk and that further deployment action will not be beneficial at this time.”

The agency isn’t denying any further attempts to disrupt the sequence, but only until the spacecraft makes its next close approach to Earth in late 2024 and warms it up enough to make progress more likely. These plans will also depend on the stability of the array during the first maneuver of the spacecraft’s main engine in February 2024.

Even if the array isn’t fully deployed and locked, NASA said the 98% deployed array could generate enough power for the spacecraft to complete its mission by passing a main belt asteroid and seven Trojan asteroids at Jupiter’s distance from the Sun. These flights will take place between 2025 and 2033.