Three separate space missions from the United States, Europe, and Japan are preparing to study the asteroid Apophis during its remarkably close, but safe, flyby of Earth on April 13, 2029. The event offers a rare scientific opportunity to observe how a planetary body's gravity affects a near-Earth asteroid.
The 340-meter (1,100-foot) wide asteroid, sometimes called the 'God of Chaos,' will pass closer to Earth than many geostationary satellites, making it visible to the naked eye for an estimated two billion people.
Key Takeaways
- Asteroid 99942 Apophis will safely pass by Earth on April 13, 2029.
- Three missions are planned to observe the event: NASA's OSIRIS-APEX, ESA's Ramses, and JAXA's DESTINY+.
- The flyby is a unique chance to study the effects of Earth's gravity on an asteroid's structure and orbit.
- Some missions face funding and logistical uncertainties but are proceeding with preparations.
A Rare Celestial Event
On Friday, April 13, 2029, the asteroid Apophis will make a close approach to Earth. While there is no risk of impact, the pass will be exceptionally near, providing scientists with an unprecedented research opportunity. The asteroid's trajectory will bring it within 32,000 kilometers (about 20,000 miles) of our planet's surface.
This proximity is significant because it is inside the orbits of geosynchronous satellites that circle Earth at approximately 36,000 kilometers. The close encounter will allow for detailed observation from both ground-based telescopes and dedicated spacecraft.
What is Apophis?
Discovered in 2004, Apophis initially caused concern among scientists due to a small probability of it impacting Earth in the future. Subsequent observations have definitively ruled out any impact risk for the foreseeable future, including the 2029 flyby. The asteroid is classified as a stony S-type asteroid.
An International Observation Campaign
Space agencies from around the world are planning to capitalize on the 2029 flyby. A coordinated effort involving three distinct missions aims to gather comprehensive data on Apophis before, during, and after its encounter with Earth's gravitational field.
The goal is to understand how planetary encounters, known as tidal forces, can alter an asteroid's internal structure, rotational state, and surface. This information is crucial for planetary defense strategies and our understanding of solar system formation.
NASA's OSIRIS-APEX Mission
NASA is repurposing its successful OSIRIS-REx spacecraft for a new mission called OSIRIS-APEX (OSIRIS-Apophis Explorer). After delivering a sample from the asteroid Bennu to Earth in 2023, the spacecraft was redirected toward Apophis.
The mission is already in space and on its way to the 2029 rendezvous. However, its continuation has faced budgetary challenges. According to Michael Nolan, the mission’s deputy principal investigator, the team is proceeding with preparations under the assumption that funding will be secured by the U.S. Congress.
"The spacecraft have different strengths. With the science teams talking to each other, we can say, 'If you make this observation, we can make that observation,' and that's a better thing than either of us could do separately." - Michael Nolan, OSIRIS-APEX Deputy Principal Investigator
ESA's Ramses Mission
The European Space Agency (ESA) is developing the Ramses mission, which stands for "Rapid Apophis Mission for Space Safety." This mission builds on the technology and expertise from ESA's Hera mission, which is currently en route to the Didymos binary asteroid system.
Scheduled for a spring 2028 launch, Ramses aims to arrive at Apophis before its close encounter with Earth. Its primary objective is to characterize the asteroid in great detail, including its orbit, surface composition, and internal structure. The mission's final funding approval is pending a decision from the ESA Ministerial Council in late November.
Ramses Mission Details
- Launch Target: Spring 2028
- Key Goal: Study how Earth's tidal forces affect Apophis.
- Payload: May carry two small cubesats. One could potentially land on the asteroid with a seismometer and magnetometer.
- Collaboration: Includes a thermal infrared camera provided by the Japan Aerospace Exploration Agency (JAXA).
Monica Lazzarin, a professor at the University of Padua in Italy, provided an update on the mission's progress at the Europlanet Science Congress, highlighting its readiness pending final approval.
JAXA's DESTINY+ Adds New Target
Japan's space agency, JAXA, also has plans to study Apophis with its DESTINY+ mission. The spacecraft's primary destination is 3200 Phaethon, the asteroid responsible for the Geminid meteor shower. However, delays in the development of its intended launch vehicle, the Epsilon S rocket, created a new opportunity.
The updated plan involves DESTINY+ launching alongside ESA's Ramses on a more powerful Japanese H3 rocket. This revised trajectory allows the spacecraft to perform a flyby of Apophis in 2029 before continuing its journey to Phaethon.
A Coordinated Scientific Effort
The teams behind all three missions are coordinating their activities to maximize the scientific return from this unique event. By combining the different instrument capabilities of OSIRIS-APEX, Ramses, and DESTINY+, scientists will be able to create a much more complete picture of Apophis and the effects of the flyby.
This collaborative approach will yield insights into the physical properties of near-Earth asteroids, which is vital for assessing potential future threats and developing effective planetary defense measures. The 2029 Apophis encounter represents a natural experiment on a scale that cannot be replicated in a laboratory, and the global scientific community is poised to watch closely.
