Keystone-SDA
(Keystone-ATS) After being impacted by a NASA spacecraft aimed to alter its trajectory, the asteroid Dimorphos will undergo close examination by the European Hera probe. The launch is set for Monday, with the goal of discovering how to safeguard humanity against potential future threats.
In a scenario reminiscent of Hollywood, the Dart mission spacecraft intentionally collided with the asteroid Dimorphos in 2022, which is a “moon” of a larger asteroid known as Didymos. This unique “planetary defense” test aimed to determine whether it is feasible to change the trajectory of an asteroid if one were to threaten Earth in the future.
It is believed that a one-kilometer object, capable of causing a global catastrophe akin to the extinction of the dinosaurs, strikes Earth approximately every 500,000 years. Additionally, a 140-meter asteroid, which could lead to a regional disaster, impacts every 20,000 years.
Among these near-Earth objects—most of which originate from the asteroid belt located between Mars and Jupiter—all known one-kilometer asteroids pose no imminent threat to our planet over the next century. Furthermore, no direct threats have been identified for those measuring 140 meters; however, only 40% of them have been classified.
Validate the technique
While this natural risk is considered “among the least probable,” we have “the advantage of being able to take measures to protect ourselves,” stated Patrick Michel, scientific manager of the Hera mission at the European Space Agency (ESA).
Dimorphos was situated approximately 11 million kilometers from Earth at the time of impact, with a diameter of around 160 meters, and it posed no threat to our planet. The NASA device, roughly the size of a large refrigerator, successfully altered its orbit, reducing it by 33 minutes.
However, the specific effects of the impact on the small asteroid remain unknown, as does its internal structure prior to the collision. Although the Dart experiment (Double Asteroid Redirection Test) demonstrated the technique’s feasibility, further understanding is needed to validate it and ascertain the energy required, if necessary, to effectively deflect a threatening asteroid.
Swiss participation
Numerical simulations indicate that Dimorphos is an aggregate of rocks held together by gravitational forces, a body into which “we sink like in cohesionless sand,” according to Mr. Michel. As a result, the Dart impact would have “completely distorted” Dimorphos, he added.
There are, however, “other possibilities,” as scientists grapple with comprehending these bodies with very low gravity, “whose behavior defies intuition,” according to Mr. Michel. The Hera mission, costing 363 million euros and equipped with 12 instruments, will carry two nanosatellites, Juventas and Milani.
The first nanosatellite aims to land on Dimorphos, marking a first for such a small object. It is outfitted with a low-frequency radar and a gravimeter to examine the asteroid’s structure and measure its gravitational field. The second nanosatellite will analyze the composition of Dimorphos utilizing a multispectral camera and a dust detector.
To determine whether the Dart mission was successful, “we first need to ascertain the mass of Dimorphos,” stated Martin Jutzi from the University of Bern, who is involved in the mission alongside astrophysicist Sabina Raducan.
Bernese researchers developed a model simulating the NASA spacecraft’s impact. According to their findings published last February, Dart not only created a crater but also completely deformed the asteroid. The research team expects to refine its conclusions based on measurements taken during the Hera mission.
Launch window
The probe is expected to be launched on Monday at 4:52 p.m. (Swiss time) from Cape Canaveral, United States, using a Falcon 9 rocket. However, a recently detected anomaly on the SpaceX launcher may necessitate a postponement of this launch. The ESA is hoping for approval from American authorities by Sunday.
The launch window extends until October 27. Following a flyby of Mars next year, Hera is scheduled to arrive near Dimorphos in December 2026, initially for a duration of six months.
At the conclusion of its mission, the Hera team hopes to provide the probe with a finale akin to that of its predecessor Rosetta, which explored the Tchourioumov-Guérassimenko comet from 2014 to 2016, by gently landing it on Dimorphos or Didymos before it ceases operations.
The Hera Probe’s Mission to Dimorphos: A New Era in Planetary Defense
(Keystone-ATS) Following the historic impact by NASA’s Dart mission, the European Space Agency’s (ESA) Hera probe is set to closely study the asteroid Dimorphos. Slated for launch on Monday, this mission aims to enhance our understanding of asteroid trajectories and planetary defense systems to protect Earth from potential future threats.
Background on the Dart Mission and Dimorphos
In a dramatic feat reminiscent of a Hollywood blockbuster, the Dart spacecraft made headlines in 2022 when it intentionally collided with Dimorphos — the smaller Moon of the larger Didymos asteroid. This pioneering “planetary defense” test was designed to explore whether we can alter an asteroid’s trajectory if one poses a threat to Earth.
Statistically, large asteroids can be dangerous; a one-kilometer object has a catastrophic potential akin to the event believed to have led to the extinction of the dinosaurs, impacting Earth every 500,000 years. In contrast, a smaller 140-meter asteroid, capable of regional devastation, strikes every 20,000 years.
Understanding Risks from Near-Earth Objects
Near-Earth objects, primarily from the asteroid belt between Mars and Jupiter, warrant monitoring. While we currently know of most asteroids over one kilometer wide, only 40% of the 140-meter asteroids have been detected, meaning potential risks remain unidentified.
Asteroid Dimorphos: Key Features
- Distance from Earth during Dart impact: Approximately 11 million kilometers.
- Size: Approximately 160 meters in diameter.
- Significance: No immediate threat to Earth.
- Result of Dart’s impact: Successfully reduced Dimorphos’s orbit by 33 minutes.
Goals of the Hera Mission
The Hera mission, with an estimated cost of €363 million, is equipped with 12 scientific instruments and will deploy two nanosatellites, Juventas and Milani. These satellites are designed to gather crucial data to assess Dimorphos’s composition and internal structure.
Key Objectives for Hera
- Validate asteroid deflection techniques.
- Investigate the internal structure of Dimorphos.
- Improve risk assessment models for larger asteroids.
The Role of Nanosatellites
Juventas will endeavor to land on Dimorphos, marking the first attempt on such a small celestial object. It is equipped with a low-frequency radar and a gravimeter to probe the asteroid’s structure. Milani, on the other hand, will analyze Dimorphos’s surface composition using a multispectral camera and a dust detector.
Simulation Insights and Predictions
| Study Aspect | Findings |
|---|---|
| Impact Dynamics | Dart’s impact likely caused complete deformation of Dimorphos. |
| Gravity Behavior | Low gravity leads to unexpected outcomes in asteroid behavior. |
| Mass Determination | Understanding Dimorphos’s mass is critical to evaluate deflection techniques. |
Timeline of the Hera Mission
The Hera probe is scheduled for launch on Monday at 4:52 PM (Swiss time) from Cape Canaveral, Florida, onboard a Falcon 9 rocket. Recent anomalies detected in the SpaceX launcher could delay this mission, with a launch window extending until October 27.
Mission Phases
- Initial Launch: Scheduled for October 2024.
- Flyby of Mars: Planned for 2025.
- Arrival at Dimorphos: Scheduled for December 2026.
- Mission Duration: Initial observations set for six months.
Long-term Impact of the Hera Mission
Ultimately, the goal is to conclude the Hera mission in a manner similar to its predecessor, the Rosetta probe, which explored comet Tchourioumov-Guérassimenko. The plan includes a soft landing onto Dimorphos or Didymos before the spacecraft’s mission concludes, providing valuable data for future planetary defense initiatives.
