An artist's impression of the Lucy spacecraft performing a flyby of a Jupiter trojan.
|Names||Discovery # 13|
|Mission type||Multiple-flyby of asteroids|
|Operator||NASA Goddard · SwRI|
|Mission duration||12 years (planned)|
|Dimensions||Length: 13 m (43 ft)|
Each solar panel: 6 m (20 ft) in diameter
|Start of mission|
|Launch date||16 October to 5 November 2021 (planned)|
|Rocket||Atlas V 401|
|Launch site||Cape Canaveral, SLC-41|
|Contractor||United Launch Alliance|
Official insignia for the Lucy mission
Lucy is a planned NASA space probe that will complete a 12-year journey to seven different asteroids, visiting a Main Belt asteroid as well as six Jupiter trojans, asteroids which share Jupiter's orbit around the Sun, orbiting either ahead of or behind the planet. All target encounters will be fly-by encounters.
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".
Lucy is planned to launch in 2021 on the 401 variant of a United Launch Alliance Atlas V rocket. 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 L4 Trojan cloud (a group of asteroids that orbits about 60° ahead of Jupiter), where it will fly by four Trojans, 3548 Eurybates (with its satellite), 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 L5 Trojan cloud (which trails about 60° behind Jupiter), where it will visit the binary Trojan 617 Patroclus with its satellite Menoetius in 2033.
The mission may end with the Patroclus–Menoetius flyby, but at that point Lucy will be in a stable, 6-year orbit between the L4 and L5 clouds, and a mission extension will be possible.
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 5.2 AU (780 million km; 480 million mi) 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.
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(s) 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 US$3 million 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 28 August 2020, NASA announced that Lucy had passed its Key Decision Point-D (KDP-D) milestone. The Lucy engineers have a “green light” to assemble and test the spacecraft and its instruments. The spacecraft instruments are expected to arrive beginning in October, which will see the Mission Operation Review procedural milestone.
By July 2021, the spacecraft should be ready to head to Florida for its launch preparations. Lucy's launch window opens on Oct. 16, 2021, and the spacecraft will make its first asteroid flyby in April 2025.
|20 April 2025||52246 Donaldjohanson||Inner main belt, member of ~130 Myr old Erigone family||4 km||C-type asteroid. Lucy will flyby the asteroid from 922 km.|
|12 August 2027||3548 Eurybates||Greek camp at L4||64 km (satellite: 1km)||C-type asteroid, largest member of the only confirmed disruptive collisional family in the Trojans. Has a small satellite.|
|15 September 2027||15094 Polymele||Greek camp at L4||21 km||P-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 2028||11351 Leucus||Greek camp at L4||34 km||D-type asteroid, slow rotator taking 466 hours per rotation.|
|11 November 2028||21900 Orus||Greek camp at L4||51 km||Characterized as a D-type and C-type asteroid by the Lucy mission team and by Pan-STARRS photometric survey, respectively. Possible binary.|
|2 March 2033||617 Patroclus||Trojan camp at L5||Patroclus: 113 km
Menoetius: 104 km
|They are binary P-type asteroids. The pair orbit at a separation of 680 km.|
|Wikimedia Commons has media related to Lucy (spacecraft).|