The European Space Agency's (ESA) Hera mission has successfully embarked on its bold adventure, launched on October 7 aboard a SpaceX Falcon 9 rocket from Cape Canaveral, Florida. This mission is fundamentally about protecting Earth from potential asteroid threats, and it marks ESA's first planetary defense endeavor.
The Hera spacecraft is on its way to the Didymos binary asteroid system, which consists of the larger Didymos body and its moonlet, Dimorphos. Previous measurements have suggested this system presents the perfect opportunity to investigate asteroid redirection after NASA’s recent historic Double Asteroid Redirection Test (DART). During this test, which occurred on September 26, 2022, DART collided with Dimorphos, successfully altering its orbit around Didymos.
The Hera mission, part of ESA’s contribution to the international Asteroid Impact and Deflection Assessment (AIDA) collaboration, aims to gather comprehensive data about Dimorphos. It hopes to provide insight on how effective DART's impact was, alongside other metrics like Dimorphos' mass, texture, and internal structure. Such knowledge is pivotal for potential future asteroid threats, serving as foundational data to refine our asteroid deflection capabilities.
Unlike any prior mission to asteroids, Hera will operate closely with two ‘CubeSats,’ shoebox-sized satellites equipped with various scientific instruments. This configuration will allow for more detailed close-range observations without having the main spacecraft risk much closer encounters. The mission is expected to provide unprecedented data on asteroid dynamics and structure.
Manufactured by OHB System AG, Hera's spacecraft and its complementary CubeSats are being supported by various technological advancements spearheaded by Thales Alenia Space, the contract holder responsible for developing key systems aboard Hera. The spacecraft's communications are capable of reaching humans on Earth from distances up to 500 million kilometers, showcasing the cutting-edge technology embedded within this mission.
A particularly intriguing aspect of Hera involves measuring the impact of DART's collision on Dimorphos. Analysts are curious to learn whether the collision created any craters or altered its physical structure significantly. Observations from earthbound telescopes, coupled with imaging from Hubble's and James Webb Space Telescopes, first hinted at the collision's success by highlighting alterations to Dimorphos’ orbit around Didymos.
Asteroids, remnants from the early solar system, have orbits bringing them close to Earth. Of the 1.3 million known asteroids, those classified as near-Earth asteroids pose the most risk, with approximately 30,000 thousands being larger than 100 meters. While smaller asteroids impact Earth frequently, typically with no noticeable explosions, mid-sized asteroids represent the most significant threat due to their destructive potential—capable of destroying entire cities if they were to collide with populated areas.
The Didymos system is significant because it replicates characteristics of other potentially hazardous asteroids; Didymos measures about 780 meters across, whilst Dimorphos is around 150 meters. Their orbits were successfully altered through human interaction for the first time, providing invaluable data for future planetary defense strategies.
Hera is scheduled to reach Didymos by October 2026, following its two-year trip. It will arrive approximately 195 million kilometers from Earth, ready to relay groundbreaking insights about this asteroid system.
While the immediate future will dictate what exactly Hera discovers, the data it returns will serve as the foundation for our planetary defense strategies, addressing the ever-present concern surrounding near-Earth asteroids. The collaboration between ESA and NASA potentially sets the stage for how humanity handles extraterrestrial threats moving forward.
The successful launch of Hera on October 7 reflects the increasing emphasis on planetary defense as scientists and space agencies around the world recognize the importance of averting potential asteroid impacts. This mission aims not only to expand our knowledge of asteroids but also to establish procedures and technologies we may need to repel future asteroid threats to Earth. The collaboration between ESA, NASA, and the private sector marks just the beginning of what's possible when international space agencies work together.
