Lucy is a NASA space probe on a twelve-year journey to eight different asteroids. It is slated to visit two main belt asteroids as well as six Jupiter trojans – asteroids that share Jupiter's orbit around the Sun, orbiting either ahead of or behind the planet. All target encounters will be flyby encounters. The Lucy spacecraft is the centerpiece of a US$981 million mission. On 4 January 2017, Lucy was chosen, along with the Psyche mission, as NASA's Discovery Program missions 13 and 14 respectively. It was launched on 16 October 2021. In November 2023 and in April 2025 it flew by and photographed asteroids Dinkinesh and Donaldjohanson, respectively. Lucy will reach its first main target, the Jupiter Trojan asteroid Eurybates, in August 2027. The mission is named after the Lucy hominin fossils, because study of the 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 hominid itself was named after the 1967 Beatles song "Lucy in the Sky with Diamonds". The spacecraft carries a disc made of lab-grown diamonds for its L'TES instrument.
Overview Lucy was launched from Cape Canaveral SLC-41 on 16 October 2021, at 09:34 UTC on the 401 variant of a United Launch Alliance Atlas V launch vehicle. It gained one gravity assist from Earth a year later on 16 October 2022, and after making a flyby of the asteroid 152830 Dinkinesh in 2023, gained another gravity assist from Earth in 2024. In 2025, it flew by the inner main-belt asteroid 52246 Donaldjohanson, which was named after the discoverer of the Lucy hominin fossil. In 2027, it will arrive at the L4 Trojan cloud (the Greek camp 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 Earth in 2031 for another gravity assist toward the L5 Trojan cloud (the Trojan camp 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 Simone Marchi of Southwest Research Institute as the mission's deputy principal investigator. NASA's Goddard Space Flight Center executes the mission under the direction of the Planetary Missions Program Office at Marshall Space Flight Center for the Planetary Science Division-Science Mission Directorate at NASA HQ. 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 (780×10^6 km; 480×10^6 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 Main-belt asteroids.
Development
NASA selected Lucy through the Discovery Program Announcement of Opportunity (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, 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 launch vehicle from Cape Canaveral, Florida. The total cost for the launch was estimated to be US$148.3 million. 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 2019, SpaceX withdrew the protest. On 28 August 2020, NASA announced that Lucy had passed its Key Decision Point-D (KDP-D) with a "green light" to assemble and test the spacecraft and its instruments. The spacecraft instruments arrived beginning with L'LORRI on 26 October 2020. On 30 July 2021, the spacecraft was transported on a C-17 transport aircraft to Florida for launch preparations, and Lucy was encapsulated into the rocket fairing on 30 September 2021. Lucy was launched on 16 October 2021 at 09:34 UTC at the opening of its 23-day launch window.
Scientific instruments In order to reduce costs and improve reliability, many of Lucy's scientific instruments are derived from previous spacecraft with similar scientific missions, most notably New Horizons and OSIRIS-REx.
L'LORRI The Lucy LOng Range Reconnaissance Imager (L'LORRI) is a high-resolution visible camera built at the Johns Hopkins University Applied Physics Laboratory. Derived from the LORRI instrument on New Horizons, It will provide the most detailed images of the surface of the Trojans. L'LORRI uses the same detector and has the same optical design as New Horizons LORRI. The primary mirror has a diameter of 20.8 cm, the system has a focal length of 262 cm, and the detector is a 1024 × 1024 thinned back-illuminated frame transfer CCD from Teledyne e2v. Each pixel subtends 5 μrad (1.03 arcseconds) and will have a point-spread function with a FWHM of less than 15 μrad (<3.09 arcseconds). Differences from the heritage instrument worth noting are the addition of redundant electronics, memory to store LORRI data, and the difference in the instrument accommodation. On New Horizons, the LORRI instrument is inside of the spacecraft, but on Lucy L'LORRI is mounted on an Instrument Pointing Platform (IPP).
… excerpt ends here. Continue reading the full article.
