The number of known near-Earth asteroids (NEAs) has just surpassed the threshold of 15000. That is a 50% increase over the number known in 2013, when we posted a similar news item on our portal for the crossing of the 10000 threshold.

Asteroid 2016 RB1 has hit the news because of a peculiar close passage on 7 September 2016 at 19:20 CEST. About the size of a cottage, the asteroid flew past our planet at an altitude of 34000 km, roughly the same as the so-called "geostationary ring" where most telecommunication satellites reside. Yet it posed no hazard neither to our planet nor to the satellite operators.

ExoMars, the ESA/Russia mission en route toward the Red Planet, has turned into a remarkable observing opportunity for asteroid hunters. The post launch outbound trajectory of the spacecraft mimics, in a reverse mode, the challenging detection of a small Earth impactor. The NEO Coordination Centre has therefore organized an international observational campaign with the aim of obtaining ground-based optical observations of the spacecraft.

The end state for most near-Earth objects (NEOs) – asteroids and comets that may pose a hazard to the Earth's ecosystem –  has for the past two decades thought to be a collision with the Sun. A new study published on Thursday 18 February in the journal Nature finds that most asteroids are destroyed much farther from the Sun than previously thought and long before they would have hit the Sun. This surprising new discovery explains several puzzling observations that have been reported in recent years.

​​​​​​The impact of WT1190F in the Indian Ocean on 13 November (see our news item on 22 October) provided an excellent opportunity to simulate the observational sequence that needs to be triggered if an actual asteroidal impactor were discovered.

An object discovered on 3 October 2015, temporarily designated WT1190F by the observers, will enter the Earth's atmosphere on 13 November. It was discovered by the Catalina Sky Survey (http://www.lpl.arizona.edu/css).

One of the major goals of the ESA NEO Coordination Centre is to focus observations on objects with non-zero impact probabilities. When an asteroid quickly becomes very faint just after discovery and stays that way for decades, the only option is to use telescopes that can see faint objects. It is essential then to be ready to catch a favourable opportunity when the object, although faint, is slightly brighter than average.

Each year, astronomers worldwide discover over 1000 new asteroids or other space rocks that could strike our planet. And if one is spotted heading towards Earth, experts working in ESA and national emergency offices need to know who should do what, and when.

NELIOTA is an activity initiated by the European Space Agency (ESA), which was recently launched at the National Observatory of Athens. The project aims to count and characterise the number and distribution of near-earth objects (NEOs). NEOs are meteoroids, comets or asteroids found in the neighbourhood of the Earth.

ESA will host the International Academy of Astronautic's 4th Planetary Defence Conference (PDC 2015), entitled ‘Assessing Impact Risk & Managing Response', at the Agency's ESRIN establishment, near Rome, 13–17 April 2015. A media briefing will be held on 16 April 2015.

If an asteroid were spotted headed towards Earth, what could humanity do about it? ESA's latest mission is part of a larger international effort to find out. This month marked the start of preliminary design work on ESA's Asteroid Impact Mission, or AIM. Intended to demonstrate technologies for future deep-space missions, AIM will also be the Agency's very first investigation of planetary defence techniques.

ESA and national disaster response offices recently rehearsed how to react if a threatening space rock is ever discovered to be on a collision course with Earth. Last month, experts from ESA's Space Situational Awareness (SSA) programme and Europe's national disaster response organisations met for a two-day exercise on what to do if an asteroid is ever found to be heading our way.  

On 18th November, ESRIN and the heart of ESA's NEO activities, the NEO Coordination Centre (NEOCC), welcomed an elaborate group of people involved in NEO activities in Europe. About 40 NEO scientists, technical, and political experts followed the final presentations and status reports of four activities carried out for ESA over the last two years.

The recent claim that asteroid 2014 UR116 may be threatening the Earth shows how difficult it is to convey the right message about the NEO hazard. The no-news spread after statements from the discoverers: the asteroid was no imminent threat but if, in a not yet foreseeable distant future, it hit the Earth then due to its large size (400 m) the effects would be devastating.

The Large Binocular Telescope (LBT), of which the Italian National Institute for Astrophysics (INAF)  is a main partner, has successfully observed asteroid 2014 KC46 in one of the faintest Near-Earth Object (NEO) recoveries ever performed. This challenging observation, which pushed the limits of the telescope down to a visual magnitude of 26.3, was carried out on the nights of 28 and 30 October 2014 by a new collaboration between the Italian LBT team and the NEO Coordination Centre of the European Space Agency.

The ESA Optical Ground Station has quickly become a major asset for the NEO Coordination Centre, thanks to the many nights devoted to observing asteroids. It is located at an altitude of 2400 m on the slope of a volcano, in Tenerife, hosted at the Observatorio del Teide - Instituto the Astrofisica de Canarias.

After discussing what to do to ensure that an important NEO is adequately monitored (see "news archive"), we will now present a possible strategy to improve the orbit of old objects, that have not been properly observed in the past.

Spotting Earth-threatening asteroids is tough partly because the sky is so big. But insects offer an answer, since they figured out long ago how to look in many directions at once.

The observational component of NEO science is an extremely important part of the impact mitigation effort, since observations are the input data for all the computational models used to predict future collisions. This post will summarize our effort to ensure that enough data are obtained, especially on the most important and challenging objects, during the short time when they are observable.

In the evening of 07 September 2014, the newly discovered asteroid 2014 RC will have a very close fly-by of just above 30000 km to our planet. The object is estimated to be between 10 and 30 m in size. While the fly-by is very close, there is no chance that the object will hit the Earth.