Hal Levison was likely to rest when he got the bad news.
NASAs Lucy spacecraft rocketed off our world at 5: 34 a.m. on October 16, 2021, so Levison and his team have been up forever preparing. It had been a magnificent, picture perfect launch, recalls Levison, who’s the Lucy mission principal investigator from the Southwest Research Institute in Boulder, Colorado. The spacecraft would soon be coming to the Trojan asteroids, unexplored fossils of the solar system that sit roughly exactly the same distance from sunlight as Jupiter. Those small space rocks, which are believed to possess formed from exactly the same processes that created the planets, could reveal how the world had become.
But, just a couple hours after launch, the team received data from Lucy that revealed that certain of her two solar arrayswhich power the spacecrafts systemshadnt fully opened. Without both solar arrays deployed, the team wasnt sure Lucy would ensure it is to her intended destination.
The essential mission was in danger, Levison says. There will be virtually no time for a nap. It had been an extremely hard day.
The team jumped into action to determine what went wrong also to devise a remedy. After months of sleuthing through the info, testing ideas on computer models and spare parts on the floor, and considering alternative trajectories for the scientific mission, the Lucy engineering team developed a plan, that they set into action earlier come early july. Now, the spacecrafts troublesome solar array is nearly completely unfurledenough so the mission can continue as planned.
Hawaii of the spacecraft is a lot, more healthy, Levison says, calling the feat pulled off by the teams engineers totally amazing and brilliant.
Once the mission engineers first discovered the issue, they didnt immediately know very well what had opted wrong. All of the data showed them was that among the solar arrays hadnt completely unfurled and latched into place. The engineers couldnt get yourself a visual because Lucys cameras point outward. Everything came through data concerning the spacecrafts performance.
Lucys solar arrays are like large folding fans. Once the spacecraft launched, the arrays were folded up. To deploy them, a motor pulled on a lanyard mounted on each array. Then, if it had reached full deployment, a latch could have held the edge of the array set up, keeping it from moving.
What we think happened is somewhere along in the deployment, that lanyard got misaligned and arrived of the spool that brings the lanyard toward the latching mechanism, explains Mark Effertz, spacecraft lead engineer for Lucy at Lockheed Martin, which built the spacecraft. The team had no direct data concerning the lanyard being tangled, he adds, however they extrapolated that it began to snarl on either side of the spool and develop a sort of bundle of lanyard because the motor kept pulling.
With the energy supply in danger, the engineers determined they had two main choices, Effertz says: They might fly Lucy as-is, and change the span of the mission. Or, they might keep tugging on the lanyard.
If the team made a decision to keep carefully the solar array partly furled, Levison says, the science team could have likely had to choose a fresh, less power-hungry trajectory for the spacecraft. And that could mean not likely to the band of eight, hand-selected Trojan asteroids.
Instead, he says, the spacecraft would travel a shorter distance to three small Trojans. Levison doesnt mince words about this alternative plan, saying those asteroids are significantly less interesting, scientifically.
Thats as the original trajectory took Lucy by way of a richly diverse band of asteroids. They range in proportions and in color from gray to red, and so are close together, allowing for the spacecraft to review many in a single trip. Its their diversity that piqued Levison among others interests, since it likely implies that these asteroids formed in far-flung regions of the solar system. Some probably hail from the outer solar system.
Levison loves to call the Trojan asteroids fossils, and also named the mission Lucy following the famous hominin fossil which has contributed significant insights to your current knowledge of early human ancestors. This mission, he explains, aims to answer questions about our origins in different ways.
Planets dont form, if youll excuse the pun, in vacuum pressure, Levison says. Planetary systems form within an ecosystem where in fact the growing planets are competing for food, theyre knocking one another around gravitationally, they maneuver around. The Trojan asteroids are remnants of the first elements of that evolutionary process and for that reason windows into our planetary origins.
Therefore the team decided the initial trajectory for the Lucy space mission was worth rescuing and devised an idea to yank the lanyard a little harder so that they can fully deploy the snagged solar array. The spacecraft had a backup motor included in its system in the event the principal motor to pull the lanyard failed.
We hardly ever really designed both motors to perform simultaneously. But we discovered that there was ways to tell the spacecraft to accomplish it anyway, Effertz says. Using both motors simultaneously gives it more torque, or pulling power, he explains. Although this maneuver doesnt detangle the snarled lanyard, it could find yourself more of the lanyard onto the spool on the tangle, pulling the array open and holding tension at risk.
The team estimates that Lucys troubled solar array is currently nearly fully open, though it isnt secured set up with the latch. That configuration appears to be generating enough capacity to get Lucy to its original target Trojans.
The engineers remain considering pulling further on the lanyard in the hopes to getting it to latch. But you can find risks associated, Effertz says. The tangle would increase and bigger, that could rub contrary to the spacecraft and that may cause new problems. They will have time and energy to decide, however, as Lucy happens to be flying by way of a region where in fact the team cant utilize the crafts antenna to download the required data, Effertz says. So any more tweaks will need to wait until around November.