On May 9, NASA’s Lucy spacecraft carried out a trajectory correction maneuver to set the spacecraft on course for its close encounter with the small main belt asteroid Dinkinesh. The maneuver changed the velocity of the spacecraft by only about 7.7 mph (3.4 m/s).
Even though the spacecraft is currently travelling at approximately 43,000 mph (19.4 km/s), this small nudge is enough to move the spacecraft nearly 40,000 miles (65,000 km) closer to the asteroid during the planned encounter on Nov. 1, 2023. The spacecraft will fly a mere 265 miles (425 km) from the small, half-mile- (sub-km)-sized asteroid, while travelling at a relative speed of 10,000 mph (4.5 km/s).
The Lucy team will continue to monitor the spacecraft’s trajectory and will have further opportunities to fine tune the flight path if needed.
The Lucy team is also continuing to analyze the data collected from its spring instrument calibration campaign and make other preparations for the mission’s first asteroid encounter. This encounter will provide a valuable test of the spacecraft’s systems and procedures to make sure that everything operates as expected during the mission’s high-speed asteroid encounters.
UPDATE AS OF DECEMBER 15, 2022: The Lucy team updated the spacecraft’s attitude controller on Dec. 6, resolving the previously observed vibration interaction between the controller and the solar array structural modes. As previously reported, the vibration was too small to pose a risk and the spacecraft continues to operate safely.
The team resumed solar array deployment activities, with an attempt on Dec. 13 that did not result in a latch. Since the estimated progress in deployment has decreased to minimal levels, the likelihood of a latch in the current thermal environment is very low. The team has therefore made the decision to suspend additional re-deployment activities through 2022. Future opportunities may be considered after careful analysis of the data and as the thermal environment changes.
Now that NASA’s Lucy spacecraft has successfully carried out its first Earth gravity assist, it has resumed high-data-rate communication with Earth. The Lucy spacecraft continues to operate safely and progress toward its mission goals.
Earlier this year, the team executed a series of commands to further deploy the spacecraft’s unlatched solar array. While deployment attempts were paused during a period of low-data-rate communications, the team continued to analyze the spacecraft’s telemetry and carry out ground-based tests. Based on these analyses, the team decided to continue attempts to further deploy the solar array. The likelihood of mission success in the current unlatched state is high, however the team expects that additional deployment—or potential latch—only improves confidence in performance without jeopardizing the spacecraft’s safety.
On Monday, Nov. 7, the spacecraft was instructed to point toward the Sun and operate the array deployment motors for a short period of time. As expected, the latest attempt deployed the wing incrementally forward, but it did not latch. The operation did succeed in providing the team with data to evaluate the array’s status and ascertain any changes since the last deployment attempt on June 16. During this analysis, the team identified that a small vibration occurred as the unlatched array interacted with the spacecraft’s attitude controller while the array was pointed toward Earth and at a cold temperature. The vibration did not occur as a result of the deployment activity itself. While this vibration is too small to pose a risk to the spacecraft in its current state, further array deployment attempts have been paused while the attitude controller is updated to resolve this issue. In the meantime, the spacecraft was reoriented so that the array is warmer, and the team found that the vibration is not present. The team will re-evaluate further redeployment activities once the updates to the controller are checked out on the spacecraft.
All of Lucy’s instruments functioned as expected during the gravity assist and provided an excellent test of the spacecraft’s systems and mission procedures. The team is continuing to analyze the images of the Earth and Moon collected during the flyby.
NASA’s Lucy mission, the agency’s first to Jupiter’s Trojan asteroids, launched at 5:34 a.m. EDT Saturday on a United Launch Alliance (ULA) Atlas V rocket from Space Launch Complex 41 at Cape Canaveral Space Force Station in Florida.
Over the next 12 years, Lucy will fly by one main-belt asteroid and seven Trojan asteroids, making it the agency’s first single spacecraft mission in history to explore so many different asteroids. Lucy will investigate these “fossils” of planetary formation up close during its journey.
“Lucy embodies NASA’s enduring quest to push out into the cosmos for the sake of exploration and science, to better understand the universe and our place within it,” said NASA Administrator Bill Nelson. “I can’t wait to see what mysteries the mission uncovers!”
About an hour after launch, Lucy separated from the second stage of the ULA Atlas V 401 rocket. Its two massive solar arrays, each nearly 24 feet (7.3 meters) wide, successfully unfurled about 30 minutes later and began charging the spacecraft’s batteries to power its subsystems.
“Today’s launch marks a genuine full-circle moment for me as Lucy was the first mission I approved in 2017, just a few months after joining NASA,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate at the agency’s Headquarters in Washington. “A true mission of discovery, Lucy is rich with opportunity to learn more about these mysterious Trojan asteroids and better understand the formation and evolution of the early solar system.”
Lucy sent its first signal to Earth from its own antenna to NASA’s Deep Space Network at 6:40 a.m. EDT. The spacecraft is now traveling at roughly 67,000 mph (108,000 kph) on a trajectory that will orbit the Sun and bring it back toward Earth in October 2022 for a gravity assist.
Named for the fossilized skeleton of one of our earliest known hominin ancestors, the Lucy mission will allow scientists to explore two swarms of Trojan asteroids that share an orbit around the Sun with Jupiter. Scientific evidence indicates that Trojan asteroids are remnants of the material that formed giant planets. Studying them can reveal previously unknown information about their formation and our solar system’s evolution in the same way the fossilized skeleton of Lucy revolutionized our understanding of human evolution.
“We started working on the Lucy mission concept early in 2014, so this launch has been long in the making,” said Hal Levison, Lucy principal investigator, based out of the Boulder, Colorado, branch of Southwest Research Institute (SwRI), which is headquartered in San Antonio. “It will still be several years before we get to the first Trojan asteroid, but these objects are worth the wait and all the effort because of their immense scientific value. They are like diamonds in the sky.”
Lucy’s Trojan destinations are trapped near Jupiter’s Lagrange points – gravitationally stable locations in space associated with a planet’s orbit where smaller masses can be trapped. One swarm of Trojans is ahead of the gas giant planet, and another is behind it. The asteroids in Jupiter’s Trojan swarms are as far away from Jupiter as they are from the Sun.
The spacecraft’s first Earth gravity assist in 2022 will accelerate and direct Lucy’s trajectory beyond the orbit of Mars. The spacecraft will then swing back toward Earth for another gravity assist in 2024, which will propel Lucy toward the Donaldjohanson asteroid – located within the solar system’s main asteroid belt – in 2025.
Lucy will then journey toward its first Trojan asteroid encounter in the swarm ahead of Jupiter for a 2027 arrival. After completing its first four targeted flybys, the spacecraft will travel back to Earth for a third gravity boost in 2031, which will catapult it to the trailing swarm of Trojans for a 2033 encounter.
“Today we celebrate this incredible milestone and look forward to the new discoveries that Lucy will uncover,” said Donya Douglas-Bradshaw, Lucy project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
NASA Goddard provides overall mission management, systems engineering, plus safety and mission assurance. Lockheed Martin Space in Littleton, Colorado, built the spacecraft. Lucy is the 13th mission in NASA’s Discovery Program. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Discovery Program for the agency.
During its 12-year mission, NASA’s Lucy spacecraft will explore eight asteroids. It will explore more asteroids than any previous mission. On its way out to the Trojan asteroids, Lucy will fly by the main belt asteroid (52246) Donaldjohanson on April 20, 2025. There, Lucy will fly by five of these L4 Trojans: Eurybates and its satellite, Queta, on Aug. 27, 2027, Polymele on Sept. 15, 2027, Leucus on April 18, 2028, and Orus on Nov. 11, 2028.
The spacecraft’s orbit will then bring Lucy back to the vicinity of the Earth for another gravity assist, and will take it again out to the distance of Jupiter. Arriving on March 2, 2033, Lucy will fly by Patroclus and its near-twin binary companion Menoetius. While the flyby of this remarkable asteroid pair will be the expected finale of the mission. Lucy will remain on a stable orbit which will enable it to visit the Trojan swarms over and over again for many thousands, and possibly millions, of years.
Lucy’s twin solar arrays have deployed. Acquisition of the signal has been confirmed and health of the spacecraft is being checked. Lucy is now operating on its own power and begins its journey to reach the Trojan asteroids.
We have spacecraft separation! Cheers and applause can be heard from the launch teams as the Lucy spacecraft separates from the United Launch Alliance Atlas V Centaur upper stage to fly freely for the first time. In just a few minutes, the spacecraft’s solar arrays will deploy.
The Centaur upper stage main engine has started its burn following on-time booster engine cutoff and Atlas/Centaur separation. The first of two burns for the Centaur main engine start will last nearly eight minutes. The payload fairing has been jettisoned.