Asteroid 2012 TC4, discovered five years ago by the Pan-STARRS survey,will come back close to Earth on 12 October 2077.It will fly-by at 44 000 km from the surface, providing a rare chance to carefully observe a small known object during its entire approach to our planet.

We took the opportunity of the ExoMars 2016 launch to organize a ground-based observational campaign. The goal was to test, in a reverse mode, the observational scenario needed to monitor the approach of a small Earth impactor. The spacecraft and other hardware related to the launch was successfully imaged;

November was a month of close approaches of many small objects. A particularly interesting case was 2015 VY105, which came to less than 30 000 km from the Earth’s surface on 15 November.

In the month of December, (29075) 1950 DA, an old NEA, entered the risk list in a peculiar way: the addition is not based on new observations but it is the combined result of an already existing good observational coverage for this object, together with a newly implemented dynamical model now available at NEODYS.

The newly discovered asteroid (469219) 2016 HO3 has been attracting the interest of the NEO community becauseof its peculiar orbital path. Having the same period of revolution of the Earth but a higher eccentricity and being properly phased, this object appears to circle our planet in a retrograde “quasi-satellite” orbit with period one year.

This month, while reading this newsletter, you will find an object designated with a “non-standard” name: XDg2F93. Labels like this, not following the standard form of year + letters + numbers,are called “temporary designations”.

On 9 May the planet Mercury will transit the Sun as seen from Earth. Although not an asteroid event, this gives us a chance to talk about how transits have been used in the past to probe the population of small asteroids extremely close to the Sun (the so-called Vulcanoids).

Over the past few days there has been a significant media interest in 2015 TB145, a large asteroid that flew past Earth on the night of Halloween. Apart for the popularity of the event generated by the date,the fly-by itself is interesting from a scientific perspective, because it was discovered only three weeks before its closest approach.

The number of known near-Earth asteroids has just surpassed the threshold of 15000. That is a 50% increase with respect to 2013, when the 10000th object was found, highlighting the ever increasing success of ground-based NEO detection surveys.

The month of September was unusually rich of close approaches. Nine objects,all with a diameter of about 10 metres, flew by our planet closer than about the distance of the Moon.

The NEO Coordination Centre web portal is an evolving environment: new services are added whenever ready to be made publicly available. This is the case for two software packages addressing key issues in NEO science: an updated NEO population model and an NEO propagator.

Over the past few weeks some media outlets discussed the future impact possibilities of asteroid (101955) Bennu, the target of the ongoing NASA mission Osiris-REx. Bennu is indeed ranked near the top of our risk list, but the earliest year when an impact is possible is 2175, not 2135 as some reports stated.

On 27 June 2018, after a cruise phase of 3.5 years, the Japanese Hayabusa 2 spacecraft rendezvoused with its target, near-Earth asteroid (162173) Ryugu. The first images sent back by the mission's cameras show a nearly spherical object, much more symmetric

On 10 February 1896 at 09:30 a large fireball appeared in the sky over the Spanish capital, Madrid. The bolide exploded at high-altitude and an air-burst was reported by many observers. Slightly more than one minute after the explosion the shock wave reached the city, causing quite some fear among the population.

During 2015-2016 ESA funded the development of two small robotic observatories, called the Test-Bed Telescopes (TBTs). The main goal is to develop and test a fully automated telescope control system to observe NEOs and space debris.

In October 2017 the Pan-STARRS survey discovered the first known interstellar object transiting through our Solar System. Named ‘Oumuamua by the discoverers, it soon became the focus of numerous observations by the world's largest professional telescopes.

Just a few days before the edition of the present newsletter a large bolide crossed the Italian northern sky. The event was observed by many people and in particular by a newly installed fireball network PRISMA (see next page). Such images have been used to determine the trajectory of the entering object.

During the past year ESA funded the refurbishment and modernization of the 0.8 m Schmidt reflector located at the Calar Alto Observatory in Spain. The telescope, identified with the MPC code Z84,is now operational and can be remotely controlled.

In our newsletter of December last year, we devoted this section to the discovery of asteroid 1997 XF11. Twenty years ago, on 11 March 1998, astronomer B. Marsden released an IAU Circular stating that the asteroid would pass within 0.002 au of Earth on 26 October 2028.

On 25 April 2018 ESA’s Gaia Data Processing and Analysis Consortium published the second release of the mission data products (known as Data Release 2, or DR2 for short). For the first time, Gaia astrometry of more than 14 000 known asteroids was made public, showing that the spacecraft can achieve astrometric precisions at the milliarcsecond level.

On 22 June 2019, around 21:26 UT (17:26 local time), a roughly 5-metre object entered the atmosphere over the Caribbean Sea, and exploded at an altitude of about 25 km over the sea surface, releasing an energy roughly equivalent to 3 kt of TNT. The explosion was first detected by the Geostationary Lightning Mapper (GLM) instrument on board the GOES-16 geostationary satellite.

For the first time since 2012 the year that just ended did not break all records of annual NEO discoveries. This was mostly due to unusually poor weather in Hawaii, where many current NEO discovery surveys are located.

September 2020 Newsletter

May will likely be the last month before summer with an average rate of NEO discoveries. Starting in June, most surveys in the South-West of the United States will likely temporarily decrease their productivity due to the summer monsoon season.

March 2020 Newsletter

On 19 October a very small asteroid, designated as 2018 UA, was discovered by the Catalina Sky Survey, and quickly flagged as a potential very close approacher. Immediate follow-up observations by both Catalina and the Spacewatch project led to a much more accurate orbit solution.

ESA's Optical Ground Station (OGS) is a facility built by ESA to support tests of optical communication between Earth and orbiting satellites. The instrument is routinely used by ESA's Space Safety...

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Summary 2022 WJ1 was the sixth impactor discovered while still outside Earth's atmosphere. Found by the Mt. Lemmon station of the Catalina Sky Survey, it impacted Earth near the Great Lakes region...

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2024 YR4 has scored the highest Torino Scale in the last 20 years

Summary 2022 EB5 was the fifth object to be detected before impacting the Earth. The meteoroid was discovered at Konkoly Observatory (Hungary) on 11 March 2022 and impacted the atmosphere over the...

Summary 2024 UQ is the tenth imminent impactor observed in space before hitting the Earth. It was first observed by ATLAS, but reported after the impact had already happened. It was subsequently...

Albedo The ratio of reflected sunlight to incident sunlight. Given an albedo and the distance of the asteroid from the Sun and the observer, the size of an object can be estimated from its...

Introduction The European Space Agency (herein the “Agency” or “ESA”) is an intergovernmental organisation established by its Convention opened for signature in Paris on 30 May 1975 having its...

Last update: 2024-08-02 14:00 UTC Exercise     Exercise    Exercise This document does not describe a real asteroid impact threat. The information here is fictional and provided only to support...

Warning: the NEO Toolkit is undergoing maintenance activities. Some functionalities might not work as expected.

Summary 2008 TC3 was the first object detected in space prior to impacting the Earth. Discovery occurred at 06:39 UTC on 7 October 2008 by the Catalina Sky Survey and the meteoroid entered the...

Summary 2018 LA was the third object to be detected before impacting the Earth. The meteoroid was discovered at 08:22 UTC on 2 June 2018 by the Mount Lemmon Survey and impacted the atmosphere over...

Summary 2014 AA was the second object to be detected before impacting the Earth. The meteoroid was discovered on 1 January 2014 by the Mount Lemmon Survey and impacted the atmosphere over the...

This table contains a list of NEAs with confirmed 100% Earth impact. The columns provide key parameters used in the assessment, including nominal impact time, absolute magnitude, and estimated size...

Providing orbital data through VO protocols.

The NEOCC is ESA's centre for observing and computing asteroid orbits and assessing their impact risk.

Close Approach Fact Sheet for asteroid 2024 YR4 (version 1.0)

Our search engine provides a comprehensive exploration of the entire asteroid database, offering a wide range of filtering options based on object group, risk class, orbital parameters,...

Summary 2019 MO was the fourth object to be detected before impacting the Earth. The meteoroid was discovered by ATLAS in Mauna Loa on 22 June 2019 and impacted the atmosphere over the Caribbean...