# Hera

> ESA spacecraft which will study the effects of the DART Impactor on the asteroid moon Dimorphos

**Wikidata**: [Q60965184](https://www.wikidata.org/wiki/Q60965184)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Hera_(space_mission))  
**Source**: https://4ort.xyz/entity/hera

## Summary
Hera is an ESA space probe launched on October 7, 2024, designed to study the effects of NASA's DART Impactor on the asteroid moon Dimorphos. As part of the Asteroid Impact and Deflection Assessment (AIDA), the mission will analyze the crater created by the impact and measure the asteroid's mass to help validate planetary defense strategies. The spacecraft carries two CubeSats, Juventas and Milani, to conduct detailed close-up observations.

## Key Facts
- **Launch Date:** October 7, 2024, at 14:52 UTC.
- **Operator:** European Space Agency (ESA).
- **Manufacturer:** OHB System AG.
- **Launch Vehicle:** Falcon 9 Block 5 (SpaceX).
- **Launch Site:** Cape Canaveral Space Launch Complex 40.
- **Mass:** 1,214 kg (launch weight); 696 kg (dry weight).
- **Dimensions:** 2.153 m (length) x 2.162 m (height) x 11.446 m (solar array span).
- **Destination:** The binary asteroid system comprising Didymos and its moon Dimorphos.
- **Payload:** Two CubeSats named Juventas and Milani.
- **Mission Milestone:** Scheduled orbit insertion at the target asteroids in November 2026.

## FAQs
### Q: What is the primary purpose of the Hera mission?
A: Hera's primary goal is to perform a detailed post-impact survey of Dimorphos, the asteroid moon struck by NASA's DART spacecraft. It aims to transform the kinetic impact experiment into a well-understood and repeatable technique for planetary defense.

### Q: When did Hera launch and when will it arrive?
A: The spacecraft launched on October 7, 2024, and is scheduled to arrive at the Didymos asteroid system for orbit insertion in November 2026.

### Q: What components make up the Hera spacecraft?
A: The mission consists of the main Hera spacecraft manufactured by OHB System AG and two piggyback CubeSats, Juventas and Milani, which will be deployed to perform closer observations.

## Why It Matters
Hera represents a critical step forward for planetary defense and space exploration safety. Following the successful impact of NASA's DART mission, Hera serves as the "crime scene investigation," providing essential data to verify if deflection is a reliable method to protect Earth from hazardous asteroids. By precisely measuring the mass and internal structure of Dimorphos, Hera will close the loop on the kinetic impactor test, ensuring that scientists fully understand the mechanics of the collision.

The mission is also significant for its technical complexity and international collaboration. As part of the Asteroid Impact and Deflection Assessment (AIDA), it combines data from both NASA and ESA to create a comprehensive model of asteroid deflection. Additionally, the deployment of the Juventas and Milani CubeSats demonstrates advanced multi-spacecraft operations in deep space, testing technologies that will be vital for future autonomous missions.

## Notable For
- **Planetary Defense Validation:** It is the first spacecraft to rendezvous with a binary asteroid system specifically to assess the results of an asteroid deflection attempt.
- **Binary Asteroid Study:** It provides the first detailed in-situ analysis of the Didymos-Dimorphos system, offering insights into the formation and properties of binary asteroids.
- **Deep-Space CubeSat Deployment:** The mission is notable for carrying two smaller spacecraft (Juventas and Milani) to perform specific scientific tasks, a capability that expands the scope of deep-space observation.
- **Mars Flyby:** The spacecraft utilizes a gravity assist at Mars in March 2025, which is a significant navigation milestone on its journey to the outer solar system.

## Body

### Mission Overview
Hera is a space probe operated by the European Space Agency (ESA) and manufactured by OHB System AG. It serves as the European contribution to the international Asteroid Impact and Deflection Assessment (AIDA). Launched on October 7, 2024, from Cape Canaveral Space Launch Complex 40 atop a SpaceX Falcon 9 Block 5, the spacecraft follows the DART (Double Asteroid Redirection Test) mission. While DART successfully impacted the asteroid moon Dimorphos, Hera’s role is to characterize the effects of that impact in detail.

### Spacecraft Specifications
The Hera spacecraft has a launch mass of 1,214 kg and a dry weight of 696 kg. Its structure measures 2.153 meters in length and 2.162 meters in height. Power is generated by two solar arrays, which span a total width of 11.446 meters and provide up to 712 watts of electricity. The spacecraft's propulsion and navigation systems are designed to support deep-space travel and precise maneuvering near small celestial bodies.

### Trajectory and Timeline
Hera’s journey to the Didymos system involves a complex trajectory:
- **Launch:** October 7, 2024.
- **Mars Flyby:** Scheduled for March 12, 2025, the spacecraft will perform a gravity assist at Mars, passing at a distance of approximately 5,000 km. This maneuver will also allow for observations of Mars and its moon Deimos.
- **Orbit Insertion:** Hera is scheduled to arrive and enter orbit around the target asteroids in November 2026.

### Payload and Scientific Operations
The mission includes two companion CubeSats:
1.  **Juventas:** Designed to study the deep interior of Dimorphos.
2.  **Milani:** Tasked with surface composition analysis.

These CubeSats will be released by Hera to conduct closer observations, eventually landing on the asteroid's surface. The main Hera spacecraft will perform a comprehensive survey, measuring the crater left by DART and determining Dimorphos's mass and structure to understand the efficiency of the kinetic impact deflection technique.

## References

1. [Source](https://www.esa.int/Safety_Security/Hera/Hera)
2. [Source](https://www.esa.int/ESA_Multimedia/Images/2020/10/After_the_crash_comes_Hera)
3. [Source](https://space.skyrocket.de/doc_sdat/hera.htm)
4. Jonathan's Space Report
5. [Source](https://www.nasaspaceflight.com/2024/10/hera-launch/)
6. [Source](https://www.esa.int/Safety_Security/Hera/Facts_and_figures)
7. [Planetary defence mission Hera heading for deflected asteroid](https://www.esa.int/Newsroom/Press_Releases/Planetary_defence_mission_Hera_heading_for_deflected_asteroid)
8. [Source](https://www.esa.int/Newsroom/Press_Releases/Planetary_defence_mission_Hera_heading_for_deflected_asteroid)
9. [Source](https://www.dlr.de/en/latest/news/2025/asteroid-mission-hera-close-flyby-of-mars-and-martian-moon-deimos)
10. [Source](https://www.esa.int/Space_Safety/Hera/Hera_asteroid_mission_spies_Mars_s_Deimos_moon)
11. [Source](https://www.esa.int/Space_Safety/Hera/ESA_s_Hera_targets_early_arrival_at_Didymos_asteroids)
12. [Source](https://www.esa.int/Enabling_Support/Operations/Hera_operations)
13. [Source](https://www.esa.int/Space_Safety/Hera/Hera_facts_and_figures)