The probe Lucy of the NASA was developed for explore the Trojan Asteroids which lie near the Lagrange points of Jupiter. It was launched last year by a rocket ULA Atlas V. However, just 12 hours after liftoff, the probe encountered a problem. One of the two solar panels installed on the spacecraft failed to fully deploy and lock.
Lucy’s solar panels have been designed to generate energy at a very great distance from the Sun. Their deployment is therefore necessary for the success of the mission. On August 3, NASA announced that a team was able to find a means of mitigating the problem to allow the mission to continue.
A few hours after the discovery of the failure, NASA set up a team to propose a response to the anomaly detected. This team is made up of scientists from the Southwest Research Institute, NASA’s Goddard Space Flight Center, and Northrop Grumman.
To find the problem, the team had to use a trick. Indeed, none of the cameras is pointed in the direction of the solar panels. The engineers then had the idea of turning on the thrusters of the machine to detect abnormal vibrations. They then created a detailed model of the solar panel motor assembly to determine the rigidity of the latter. The results showed that a cord designed to open the array of solar panels was probably snagged on its reel.
The proposed solutions
Two solutions were proposed by the team. The first was to use the panel as is since it could generate 90% of the expected energy. The alternative was to try to pull harder on the lanyard using both the emergency deployment motor and the main motor at the same time, the aim of this maneuver being to succeed in engaging the lock.
These two engines, however, were never designed to run at the same time. The team therefore decided to do some modeling to test the possible results and the potential effects. Months of simulation were necessary and finally, the team decided to try solution number 2. They activated both engines simultaneously, 7 times in a row, and managed to open and stretch the solar panel a little more.
However, the engineers were not 100% successful since the maneuver did not activate the lock. But according to NASA, the panel is currently stable enough for the craft to continue normal operations.
The next step for the Lucy mission is to use Earth’s gravity to propel itself. This maneuver will take place next October. The probe is expected to reach its first asteroid in 2025.