NASA’s DART Mission Successfully Alters Asteroid’s Orbit Around the Sun

In a landmark achievement for planetary defense, NASA’s Double Asteroid Redirection Test (DART) mission has not only altered the orbit of the asteroid Dimorphos around its companion asteroid Didymos, but has similarly measurably shifted the orbit of the asteroid pair around the Sun. This marks the first time humanity has demonstrably changed the path of a celestial body’s orbit around our star.

The DART Mission and its Impact

The DART spacecraft intentionally collided with Dimorphos in September 2022, a feat captured by the Italian Space Agency’s LICIACube. Observations following the impact revealed a change in the 770-day orbital period of Didymos and Dimorphos around the Sun, a change measured in fractions of a second [NASA]. Prior to the impact, the mission successfully shortened Dimorphos’s orbit around Didymos by 32 minutes [ScienceNews].

How the Change Was Measured

Astronomers utilized a technique called stellar occultations to precisely measure the orbital shift. This involves observing the asteroids as they pass in front of distant stars, momentarily dimming the starlight. By analyzing these “blinks,” researchers were able to determine the asteroids’ position, shape, and speed with remarkable accuracy. Twenty-two such eclipses were captured over several years [ScienceNews].

Significance for Planetary Defense

While the change in orbital velocity is currently small – approximately 1.7 inches (4.3 centimeters) per hour – scientists emphasize that even a minor intervention can accumulate over time, potentially altering an asteroid’s trajectory enough to prevent a future impact with Earth [ScienceNews]. The DART mission demonstrates the viability of the kinetic impactor technique as a method for defending our planet against hazardous asteroids.

Future Planetary Defense Efforts

NASA is continuing to develop planetary defense strategies, including a telescope designed to detect demanding-to-observe objects like dark asteroids and comets [NASA]. The DART mission, launched in November 2021, is a key component of the agency’s broader efforts to protect Earth from potential asteroid threats [Wikipedia].

Key Takeaways

• The DART mission successfully altered the orbit of an asteroid pair (Didymos and Dimorphos) around the Sun.
• This is the first time a human-made object has measurably changed the path of a celestial body around the Sun.
• The change was measured using stellar occultations, a technique involving observing the dimming of starlight as asteroids pass in front of stars.
• The mission validates the kinetic impactor technique as a viable planetary defense strategy.
• NASA is continuing to develop additional planetary defense technologies.