Lucy (spacecraft)


Lucy is a planned NASA space probe that will tour five Jupiter trojans, asteroids which share Jupiter's orbit around the Sun, orbiting either ahead of or behind the planet and one main belt asteroid. All target encounters will be fly-by encounters.
On 4 January 2017, Lucy was chosen, along with the Psyche mission, as NASA's Discovery Program missions 13 and 14 respectively.
The mission is named after the 'Lucy' hominin skeleton, because the study of Trojans could reveal the "fossils of planet formation": materials that clumped together in the early history of the Solar System to form planets and other bodies. The Australopithecus itself was named for a Beatles song, "Lucy in the Sky with Diamonds".

Overview

Lucy is planned to launch in 2021. In 2025, it will fly by the inner main-belt asteroid 52246 Donaldjohanson, which was named for the discoverer of the Lucy hominin fossil. In 2027, it will arrive at the Trojan cloud, where it will fly by four Trojans, 3548 Eurybates, 15094 Polymele, 11351 Leucus, and 21900 Orus. After these flybys, Lucy will return to the vicinity of the Earth whereupon it will receive a gravity assist to take it to the Trojan cloud, where it will visit the binary Trojan 617 Patroclus with its satellite Menoetius in 2033.
Three instruments comprise the payload: a high-resolution visible imager, an optical and near-infrared imaging spectrometer and a thermal infrared spectrometer.
Harold F. Levison of the Southwest Research Institute in Boulder, Colorado is the Principal Investigator, with Catherine Olkin of Southwest Research Institute as the mission's Deputy Principal Investigator. NASA's Goddard Space Flight Center will manage the project.
Exploration of Jupiter Trojans is one of the high priority goals outlined in the Planetary Science Decadal Survey. Jupiter Trojans have been observed by ground-based telescopes and the Wide-field Infrared Survey Explorer to be "dark with... surfaces that reflect little sunlight". Jupiter is from the Sun, or about five times the Earth-Sun distance. The Jupiter Trojans are at a similar distance but can be somewhat farther or closer to the Sun depending on where they are in their orbits. There may be as many Trojans as there are asteroids in the asteroid belt.

Development

NASA selected Lucy through the Discovery Program AO released on 5 November 2014. Lucy was submitted as part of a call for proposals for the next mission for Discovery Program that closed in February 2015. Proposals had to be ready to launch by the end of 2021. Twenty-eight proposals were received in all.
On 30 September 2015, Lucy was selected as one of five finalist missions, each of which received to produce more in-depth concept design studies and analyses. Its fellow finalists were DAVINCI, NEOCam, Psyche and VERITAS. On 4 January 2017, two of the five proposals—Lucy and Psyche—were selected for development and launch.
On 31 January 2019, NASA announced that Lucy would launch in October 2021 on an Atlas V 401 rocket from Cape Canaveral, Florida. The total cost for the launch is estimated to be.
On 11 February 2019, SpaceX protested the contract award, claiming that it could launch Lucy into the same orbit at a "significantly cheaper cost". On 4 April, SpaceX withdrew the protest.

Science payload

The science payload includes:
Targets with their flyby dates include:
DateTargetGroupDiameterType
20 April 202552246 DonaldjohansonInner main belt, member of ~130 Myr old Erigone family4 kmC-type asteroid. Lucy will flyby the asteroid from 922 km.
12 August 20273548 EurybatesGreek camp at 64 km C-type asteroid, largest member of the only confirmed disruptive collisional family in the Trojans. Has a small satellite.
15 September 202715094 PolymeleGreek camp at 21 kmP-type asteroid that may be a collisional fragment of a larger P-type asteroid. Its red color suggests surface is rich in organic compounds called tholins.
18 April 202811351 LeucusGreek camp at 34 kmD-type asteroid, slow rotator taking 466 hours per rotation.
11 November 202821900 OrusGreek camp at 51 kmCharacterized as a D-type and C-type asteroid by the Lucy mission team and by Pan-STARRS photometric survey, respectively. Possible binary.
2 March 2033617 PatroclusTrojan camp at Patroclus: 113 km
Menoetius: 104 km		They are binary P-type asteroids. The pair orbit at a separation of 680 km.

s every six years.