The European Space Agency (ESA) has published an animation made by the Hera probe. Leaving its home planet, it looked back to show the Moon orbiting around it.
The Hera mission was launched on October 7. Its target is the double asteroid Didymos. In September 2022, a NASA probe crashed into its companion Dimorphos. The bombardment was part of an experiment to test methods of deflecting dangerous celestial bodies away from Earth. Hera will have to study the location of the impact and how it impacted a pair of asteroids.
Shortly after Hera launched, engineers activated its scientific instruments to test and calibrate them. One of them is the TIRI (Thermal Infrared Imager) instrument provided for the mission by the Japan Aerospace Exploration Agency.
TIRI is designed for mid-infrared imaging of Dimorphos. Based on a chart of the ‘thermal inertia’ of surface areas (i.e., the rate of change in their temperature), scientists will be able to estimate their physical properties such as roughness, particle size distribution, and porosity.
To test TIRI’s performance, mission specialists decided to target the Earth and the Moon. The instrument captured them between October 10 (when Hera was at a distance of 1.4 million km from Earth) and October 15 (by this date Hera had moved away to a distance of 3.8 million km). The animation published by ESA shows how the Earth gradually decreases in size, while the Moon, moving around our planet, changes phases and its disc from half-lit to fully lit.
Provided by ESA
