NASA’s OSIRIS-APEX spacecraft recently captured striking images of Earth and the Moon while executing a gravity-assist maneuver, propelling it toward the asteroid Apophis. This mission marks the next phase of the OSIRIS-REx program, which previously delivered a sample from asteroid Bennu in 2023, and now shifts focus to a vastly different celestial body.
Earth Flyby: A High-Speed Encounter
On September 23, OSIRIS-APEX passed just 2,136 miles (3,438 kilometers) above Earth, capturing detailed images of swirling clouds, blue oceans, and passing continents. The probe’s MapCam and StowCam imagers functioned flawlessly, confirming operational readiness after years in deep space. The spacecraft continued its journey and captured a dramatic shot of the Moon the following day, from a distance of approximately 370,000 miles (595,000 kilometers).
Why This Matters: Gravity Assists and Asteroid Studies
This flyby wasn’t just for show. It leveraged Earth’s gravity to accelerate OSIRIS-APEX toward its primary target: Apophis. Gravity assists are a crucial technique in deep-space exploration, allowing missions to reach distant destinations faster and more efficiently without expending excessive fuel.
Apophis is particularly interesting because of its close approach to Earth in 2029. The asteroid will pass closer than some satellites, exposing it to powerful tidal forces that could reshape its surface and even alter its orbit. The OSIRIS-APEX mission is designed to study this phenomenon directly.
The Apophis Mission: What to Expect
Once in orbit around Apophis (estimated arrival shortly after the 2029 close approach), the spacecraft will spend approximately 18 months mapping the asteroid’s composition and capturing high-resolution imagery. Mission planners intend to hover close to the surface and use thrusters to stir up dust, revealing previously hidden materials. This will provide unprecedented insight into how asteroids respond to gravitational stress and planetary proximity.
The contrast between Apophis and Bennu, the asteroid visited by the initial OSIRIS-REx mission, is also significant. Bennu is carbon-rich, while Apophis is metal-rich, offering scientists a comparative opportunity to study diverse asteroid compositions.
This mission represents a unique chance to witness and document an asteroid’s response to extreme gravitational forces, enhancing our understanding of near-Earth objects and potential planetary hazards.
The images from Earth and the Moon serve as an early confirmation of the spacecraft’s capabilities, setting the stage for a groundbreaking study of Apophis in the years ahead.
