Hera (space mission) facts for kids
Artist's impression of Hera in orbit around the asteroid Didymos
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| Mission type | Didymos orbiter |
|---|---|
| Operator | European Space Agency |
| Mission duration | Planned (science phase): 6 months |
| Spacecraft properties | |
| Manufacturer | OHB SE |
| Launch mass | 1,128 kg (2,487 lb) |
| Dry mass | 350 kg (770 lb) |
| Dimensions | 1.6 × 1.6 × 1.7 m (5.2 × 5.2 × 5.6 ft) |
| Start of mission | |
| Launch date | 7 October 2024, 14:52:11 UTC (10:52:11 am EDT) |
| Rocket | Falcon 9 Block 5 (B1061.23) |
| Launch site | Cape Canaveral, SLC‑40 |
| Contractor | SpaceX |
| Flyby of Mars | |
| Closest approach | March 2025 |
| Distance | 5,000–8,000 km (3,100–5,000 mi) |
| 65803 Didymos orbiter | |
| Orbital insertion | 14 December 2026 |
 Mission insignia |
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Hera is a special spacecraft built by the European Space Agency (ESA). Its main job is to study a pair of asteroids called Didymos. Four years before Hera arrives, another spacecraft, DART from NASA, crashed into the smaller asteroid, Dimorphos.
Hera will check out the crash site. It will measure the size of the crater and how much the asteroid's path changed. This helps scientists learn if we can push away a dangerous asteroid if it ever threatens Earth. Hera will also look at the dust cloud created by the impact.
The spacecraft launched on October 7, 2024, on a SpaceX Falcon 9 rocket. It will arrive at Didymos in 2026. Hera weighs about 1,128 kilograms (2,487 pounds). It carries cameras, an altimeter (to measure height), and a spectrometer (to study light). It also carries two smaller spacecraft called Milani and Juventas.
Hera will explore the asteroids' makeup and how they are built inside. It will also test new ways to fly spacecraft close to small space objects. It will practice sending and receiving messages from the small CubeSats in deep space.
Contents
The Story of the Hera Mission
Working with NASA to Protect Earth
Scientists from NASA and ESA started a project called AIDA in 2013. This was the first time they planned to test a way to push away asteroids that might hit Earth. The plan was to send two spacecraft to the binary asteroid Didymos.
NASA's spacecraft, DART, would crash into the smaller asteroid. ESA's spacecraft, called AIM, would watch the crash and measure its effects.
Hera's Beginning
In 2016, ESA decided not to build AIM because they didn't have enough money. NASA, however, kept working on DART. Ground telescopes would help watch the DART impact instead of AIM. DART later added a tiny satellite called LICIACube to film the first moments of the crash.
In 2017, ESA decided to restart the project. They named the new mission Hera, after the Greek goddess of marriage. Hera would do everything AIM was supposed to do. It would use as many parts from the old AIM design as possible.
Hera was planned to launch in October 2024. This timing was important to catch the asteroids at the right place. It would study the effects of the DART impact on Dimorphos, four years after it happened. ESA officially approved the Hera mission in November 2019.
In September 2020, ESA hired a group of companies led by OHB to build the spacecraft. The mission then moved to its final testing phase in March 2024.
What Hera Hopes to Achieve
The main goal of the Hera mission is to check if hitting an asteroid with a spacecraft can change its path. This method is called the kinetic impactor method. It means hitting an asteroid at high speed to push it away. This is one of the best ways we know to protect Earth from a dangerous asteroid.
To do this, Hera needs to find out:
- How much the asteroid's path changes based on its density, how porous it is, and what its surface and inside are like.
- How much of the crash energy breaks up the asteroid or pushes out material.
Hera also has important science goals. It will gather details about both asteroids. It will study their surfaces and, for the first time, look inside an asteroid. The JuRa radar on the Juventas CubeSat will help with this. Hera will map Dimorphos in great detail. It will also figure out the exact weight of Dimorphos. This helps scientists understand how well DART's impact worked.
The mission also has technology goals. A key goal is to create smart guidance software. This software will use data from different sensors to help Hera fly safely around the asteroid by itself.
Hera also carries two small CubeSats. They will be released once Hera reaches the asteroids.
- Juventas will measure the asteroid's inside and its gravity. It will also check how the surface reacts if it lands on Dimorphos.
- Milani will collect data on the surface of both asteroids. It will look for dust around them.
How the Mission Will Work
The DART mission launched on November 24, 2021. It reached the binary asteroid system (65803) Didymos on September 26, 2022. DART crashed into Dimorphos, the smaller asteroid, at about 6.6 kilometers per second (4.1 miles per second). This impact was meant to change Dimorphos's orbit around Didymos by at least 73 seconds. Telescopes on Earth watched for this change.
Hera launched on October 7, 2024. It will perform a deep-space maneuver in November. It will then get a boost from Mars in March 2025. During this time, Hera will observe Deimos, one of Mars's moons.
Hera will arrive at the Didymos system on December 28, 2026. This is four years after DART's impact. It will then spend six months studying the asteroids. Hera will be the first spacecraft to visit a binary asteroid system.
Once near the asteroids, Hera will follow five steps:
- Early study: First, it will get a general idea of the asteroids.
- CubeSat release: Then, it will let go of its two small satellites.
- Detailed study: After that, it will do a very close study.
- Close-up look: It will get even closer to observe.
- Landing: Finally, both Milani and Juventas will try to land on Dimorphos. The main Hera spacecraft might even try to land on Didymos.
The Hera Spacecraft
The main part of the Hera spacecraft is shaped like a box. It is about 1.6 x 1.6 x 1.7 meters (5.2 x 5.2 x 5.6 feet). It has two solar panels that stick out from its sides. A large dish antenna is on one side for talking to Earth.
When launched, the spacecraft weighed about 1,214 kilograms (2,676 pounds). Its solar panels cover about 13 square meters (140 square feet). Hera uses special engines to move around and control its direction. It also has two cameras called Asteroid Framing Cameras (AFC) to help it navigate.
Scientific Tools on Hera
Asteroid Framing Cameras (AFC)
Hera's main tools are its two AFC cameras. These cameras are identical and act as backups for each other. They take black and white pictures. They can see details as small as one meter (3.3 feet) from 10 kilometers (6.2 miles) away. These cameras will help map the surfaces of Didymos and Dimorphos. They will also look at the crater DART made and find a safe spot for Juventas to land.
Hyperspectral Imager – HyperScout-H
HyperScout-H is a special camera that takes images in many different colors, including light we can't see. It helps scientists understand what the asteroid's surface is made of.
Planetary Altimeter (PALT)
PALT is a laser tool that measures how far away Hera is from the asteroid's surface. It uses an infrared laser beam. It can measure altitude very accurately, within 0.5 meters (1.6 feet).
Thermal Infrared Imager (TIRI)
TIRI is a camera from the Japanese space agency, JAXA. It sees heat, not visible light. This helps scientists understand the temperature of the asteroid's surface.
X-Band Radio Science (X-DST)
Scientists will use radio waves to figure out the weight of the asteroids. They will also learn about their gravity, how fast they spin, and their orbits. This is done by measuring small changes in the radio signals between Hera and Earth. It also uses signals between Hera and the CubeSats.
Tools on the Small Satellites
Hera carries two small CubeSats, Milani and Juventas. They will be released before Hera gets to the Didymos asteroid system. These small satellites will do extra studies that help Hera's mission.
Both CubeSats are similar. They weigh about 12 kilograms (26 pounds) each. They can control their direction in space. They talk to Hera using radio signals. These radio signals also help measure the asteroids' gravity. They have cameras and special sensors to help them move and study the asteroids. If they land on Dimorphos, they have tools to check the surface properties.
CubeSat Milani
The Milani CubeSat is named after a mathematician, Andrea Milani. Its job is to take pictures and look for dust around the asteroids. It will map both asteroids and study their surfaces. It will also check the effects of the DART impact.
Milani has two main tools:
- The ASPECT hyperspectral imager takes pictures in many colors, including light we can't see. It helps understand the surface materials.
- The VISTA thermogravimeter looks for dust, water, and other light materials.
CubeSat Juventas
Juventas will study the physical features of Dimorphos. It will map its gravity and figure out what's inside the asteroid. It will also study the surface.
Juventas carries these tools:
- The JuRa radar is the first tool to look inside an asteroid. It uses radio waves to see layers beneath the surface.
- The GRASS gravimeter measures gravity very precisely.
- A camera to take pictures.
- Its radio link with Hera helps measure the asteroid's gravity.
See also
In Spanish: Hera (sonda) para niños
- Near-Earth Object Coordination Centre (ESA's NEOCC)
- Planetary Defense Coordination Office (NASA's PDCO)
- Double Asteroid Redirection Test (DART mission)
