By Lucy Intern David Dezell Turner
As with any hero’s journey, the story of the Lucy Mission begins with a call to adventure. It came this time in the form of the Planetary Science Decadal Survey. Every ten years, NASA and the US National Research Council survey the planetary science community in order to determine the most interesting science questions that NASA should pursue over the next ten years, and what missions it should support. For the 2013-2022 Decadal Survey, the community wanted a mission to explore the diversity of the Trojans, a group of primitive asteroids left largely unchanged since the formation of the solar system. No mission has ever visited these “fossils” of the early solar system before. Who would dare look the Decadal Survey in the metaphorical eyes and accept this challenge? Hal Levison and Cathy Olkin, who would lead their proposed mission as Principal Investigator and Deputy Principal Investigator. Levison is a co-author of the Nice Model, so he had already been researching the origins of the Trojans, and Olkin was an instrument lead on New Horizons (the mission responsible for the most detailed photographs of Pluto’s surface) and the Principal Investigator of a highly rated mission proposal from 2010 called Lucy. Named after a primate fossil that was instrumental in helping humankind understand our own origins, Olkin’s mission would have explored one Trojan and one Centaur, which would have helped us better understand the origins of our solar system.
This time, however, Levison and Olkin ambitiously set out to visit a variety of Trojan asteroids, each interesting for different reasons. They knew they wanted to observe the peculiar (3548) Eurybates, which is a part of the Trojans’ largest collisional family, and the much more typical (219000) Orus, which is dark red and possibly full of organics. The mission would also have to abide by NASA’s Planetary Protection policy, which states that a spacecraft cannot collide with Mars or Europa for at least 50 years. As Levison checked the spacecraft’s planned trajectory for possible collisions, he noticed Lucy also passed by (617) Patroclus and Menoetius, a pair of nearly equal-size asteroids that orbit each other. (Over the course of mission development, three more asteroids would be added to the mission’s path, and a satellite of Eurybates would be discovered, bringing the total to a record-shattering eight asteroids.) Building on the mission concept that nearly was, Levison and Olkin decided to call their new mission Lucy, and they began working on the proposal in March of 2014. They planned for Lucy to be a Discovery class mission, meaning the cost before launch could not exceed $450 million.
To build the spacecraft, the team partnered with Lockheed Martin, the company behind the spacecraft for the OSIRIS-REx mission to asteroid Bennu. Since the mission concept was still in its early stages, the team created a rough spacecraft design that Levison christened a “LEGO spacecraft” (a nickname he suspects might annoy the engineers), so called because it was made up of successful parts from existing spacecraft. During this stage, the team focused more on the scientific purpose of each part than whether the parts could form a cohesive whole. If they advanced to the next round, NASA would provide funding for development of a more robust design. (The current design retains this LEGO spirit somewhat, as the instruments are heavily based on instruments from New Horizons and OSIRIS-REx.) The team then decided to partner with a NASA center. Though some smaller, less expensive missions choose not to, the Lucy team knew that their mission was large enough that they would benefit immensely from a NASA partnership. They selected Goddard Space Flight Center, known for its incredible track record in the field of planetary science. Goddard was behind OSIRIS-REx, New Horizons, the Hubble Space Telescope, and the Curiosity Rover, to name a few.
In February of 2015, the team submitted their 250-page proposal — along with 27 other teams — and waited. On September 30, 2015, NASA announced that Lucy and four other finalists would move on to the next round of selection. Each team was awarded $3 million to continue developing their missions. During this time, the Lucy team added three new asteroid targets to the spacecraft’s trajectory (bringing the total to seven, for those of you counting at home; the eighth, Eurybates’ satellite, was not discovered until January 2020). Then in August 2016, the team submitted their Concept Study Report, an extremely technical 929-page behemoth that Olkin calls “a proposal on steroids.”
That November, the Lucy crew faced their biggest trial yet: the Site Visit. For nine-and-a-half intense hours, the team was interrogated by a panel of 40 experts from NASA. The panel’s areas of expertise ran the gamut from propulsion to instruments, from scheduling to communications. “You need to know everything and have all the [Lucy team’s] experts lined up, because no one knows everything about [the mission]…” Olkin explains. The team also had to prepare presentations. They were given a set of questions beforehand, then grilled with questions throughout the day. By putting the team in a high-stress situation, the panel was also able to assess how well they worked together, Levison explains. He admits the Site Visit is the most difficult thing he has ever done, but since his team was prepared, he was surprised to find that he enjoyed it.
Finally, on January 4, 2017, NASA announced that it would select two Discovery class missions from the five candidates: Psyche (a mission to a metallic asteroid) and Lucy. It seems surviving the Discovery gauntlet together has fostered a kinship between Psyche and Lucy, as Olkin affectionately refers to Psyche as Lucy’s “sister mission.”
But as with any hero’s journey nowadays, that was only the first adventure, a setup for a multitude of sequels. Getting selected simply meant the completion of Phase A, the first film in the six-phase Lucy Cinematic Universe. It didn’t take a post-credits scene for the Lucy team to know that their work wasn’t over just yet.