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NASA's Lucy Spacecraft Prepares for Second Earth Gravity Assist

On December 12, at 11:15 p.m. EST, NASA's Lucy spacecraft, currently in a two-year orbit around the sun, will skim Earth's atmosphere, passing only about 220 miles (360 kilometers) above the surface. This close flyby will result in a gravity assist, putting the spacecraft on a new trajectory that travels through the main asteroid belt and out to the never-before-explored Jupiter Trojan asteroids, small bodies that orbit the sun at the same distance as Jupiter.

Overview of Lucy's Mission

The Lucy mission, named after the famous fossilized human ancestor, aims to study the Trojan asteroids that hold clues regarding the early solar system's formation. By examining these primitive bodies, scientists hope to gain insights into the processes that led to planet formation. Lucy's journey will span a total of 12 years, involving multiple gravity assists to modify its trajectory.

Significance of the Second Earth Gravity Assist

This second gravity assist occurs three years into Lucy's mission. Its first gravity assist on October 16, 2022, boosted the spacecraft from an initial one-year orbit onto its current orbital path. This assist allowed Lucy to approach the well-known asteroid Dinkinesh and its satellite, Selam.

Upcoming Trajectory

Trajectory Path

During this gravity assist, Lucy will approach from the direction of the sun. Thus, observers on Earth will not be able to see the spacecraft approaching due to the sun's glare. Lucy's trajectory will bring it closer to the Earth than the International Space Station

Safety Procedures

To ensure the spacecraft's safety as it flies through the congested region populated by Earth-orbiting satellites and debris, NASA has implemented robust protocols. These procedures will allow for the anticipation of potential collisions.

Pre-Collision Maneuvers

If necessary, Lucy will execute a small trajectory correction maneuver 12 hours before closest approach to alter the timing of closest encounter by 1 or 2 seconds—enough to avoid a potential collision.

Observation Opportunities

Shortly after sunset in the Hawaiian Islands, keen observers might catch a glimpse of Lucy as it approaches Earth before disappearing into Earth's shadow. It will speed over the continental U.S. at over 33,000 miles per hour (14.8 kilometers per second), reemerging from Earth's shadow about 20 minutes later.

Future Encounters

Following this gravity assist, Lucy's speed with respect to the sun will increase by more than 16,000 miles per hour (7.31 kilometers per second). The next asteroid encounter is targeted for April 20, 2025, with the small main belt asteroid Donaldjohanson.

During the first Earth gravity assist, the spacecraft had the opportunity to image the Earth and the moon as part of an instrument calibration. However, there are no further calibrations necessary at this time, and the instruments will remain off during the upcoming encounter.

Conclusion

The Lucy mission represents a significant scientific endeavor aimed at unraveling the mysteries of our solar system's past. As it prepares for this crucial second earth gravity assist, the science community anticipates the wealth of information that will emerge from its encounters with the Trojan asteroids

For More Information

For additional updates on the Lucy mission, please refer to NASA's announcements and subscribe to their newsletter for the latest news in space exploration.

References

For more information, please refer to the sources below:

• NASA Homepage
• NASA Lucy Mission Page
• Publish Date: December 12, 2024

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