Hera Says Farewell to the Earth and Moon

Author: Andy Tomaswick

Published on: October 16, 2024

Testing the equipment on an interstellar mission is one of the first things operators do when the spacecraft successfully launches. In some cases, those tests show the future troubles the mission will face, such as what happened to NASA’s Lucy mission a few years ago. However, in some cases, the mission provides us with perspectives we might never have seen before, which was the case for Hera, ESA’s mission to Dimorphos. This asteroid was deflected successfully during NASA’s DART (Double Asteroid Redirection Test) mission in 2022.

Hera was successfully launched on October 7th and carries a series of instruments designed to peer at the asteroids using various wavelengths. Some instruments were turned toward the Earth and Moon from about a million kilometers away as part of the mission’s Near-Earth Commissioning Phase. The resulting pictures showcase the spacecraft’s capabilities and provide a new perspective of our “terraqueous globe,” as Carl Sagan once put it, alongside our much more sterile neighbor, the Moon.

First Images from Hera

The first images of Earth and the Moon, taken by Hera, highlight the spacecraft's innovative instruments. Here are three of the major capturing systems utilized during this initial phase:

1. Asteroid Framing Camera (AFC)

Earth and Moon from the AFC — Image of the Earth (left) and Moon from Hera’s AFC. Credit – ESA

This monochrome 1020×1020 image, the clearest of the three, effectively gives an idea of the scale between the Earth and the Moon, which can often be hard to gauge from the planet’s surface.

2. Thermal Infrared Imager (TIRI)

Thermal Imagery of the Earth and Moon — Image of the Earth (center) and Moon from Hera’s TIRI. Credit – ESA

TIRI captured this image from a distance of approximately 1.4 million kilometers, three times the distance from the Earth to the Moon itself. TIRI is designed to capture infrared wavelengths, which represent heat. Observing Dimorphos over time will help scientists understand the “thermal inertia” of certain regions, revealing vital physical properties of the asteroid.

3. Hyperscout H

Hyperscout H Image — Image of Earth (bottom left) and Moon from Hera’s Hyperscout H imager. Credit – ESA

Hyperscout H captures Dimorphos in wavelengths that are not visible to the human eye, specifically between 650 nm to 950 nm (near infrared). The imager employs a false color depiction, showcasing shorter wavelengths in shades of blue while longer wavelengths appear red.

Significance of the Images

The Earth and Moon have been imaged millions of times before in these wavelengths. However, these images serve an essential proof of concept for the operation of Hera’s systems. The three cameras make up significant components of Hera’s “asteroid deck,” which houses several essential instruments, including a laser rangefinder and antennas for deep-space communication with Earth.

Upcoming Missions and Future Studies

While many of the other instruments will have to wait until the craft's arrival at the binary asteroid system in December 2026, researchers hope that Hera will provide more images of its journey and the asteroid's surface composition.

Learn More:

The ongoing assessments and future missions involving Hera will open new pathways to understanding the complexities of asteroid interactions and the potential hazards they pose. As research unfolds, our perspective on these celestial bodies will deepen significantly.

Lead Image:
Image of Earth from the AFC
Credit – ESA

For more information, visit Universe Today