NEO Coordination Centre


Precursor services

Current number of known NEAs:
Current number of NEAs in risk list:
Last update: 2018-12-16 10:16:00 UTC


Learning from lunar lights

7 December 2018

Every few hours observing the Moon, ESA’s ‘NELIOTA’ project discovers a brilliant flash of light across its surface – the result of an object hurtling through space and striking our unprotected rocky neighbour at vast speed. Based at the Kryoneri telescope of the National Observatory of Athens, this important project is now being extended to January 2021.

From the Moon’s past, to Earth’s future

Location of the impact flashes detected so far by NELIOTA

Impact flashes are referred to as ‘transient lunar phenomena’, because although common, they are fleeting occurrences, lasting just fractions of a second. This makes them difficult to study, and because the objects that cause them are too small to see, impossible to predict.

For this reason scientists are studying lunar flashes with great interest, not only for what they can tell us about the Moon and its history, but also about Earth and its future.

By observing lunar impacts, NELIOTA (NEO Lunar Impacts and Optical TrAnsients) aims to determine the size and distribution of near-Earth objects (NEOs) – meteoroids, asteroids or comets. With this information, the risk these space rocks pose to Earth can be better understood.

The world’s largest eye on the Moon

In February 2017, a 22-month campaign began to observe lunar flashes with the 1.2 metre Kryoneri telescope, the largest telescope on Earth to monitor the Moon.

The flashes of light caused by lunar impacts are far dimmer than the sunlight reflected off the Moon. For this reason, we can only observe these impacts on the Moon’s ‘dark side’ – between New Moon and First Quarter, and between Last Quarter and New Moon. The Moon must also be above the horizon, and observations require a fast-frame camera, such as the Andor Zyla sCMOS used in the NELIOTA project.

To date, in the 90 hours of possible observation time that these factors allowed, 55 lunar impact events have been observed – a detection rate of about 2x10-7 flashes per hour, per square kilometre. Extending this to the entire surface of the Moon gives a final rate of almost 8 flashes per hour. With the extension of this observing campaign to 2021, further data should improve impact statistics.

The NELIOTA system is the first to use a 1.2-metre telescope for monitoring the Moon, and as such is able to detect flashes two magnitudes fainter than other lunar monitoring programs, which typically use 0.5-metre telescopes or smaller.

Another unique feature of the NELIOTA project is its ability to monitor the Moon in two ‘photometric bands’, which recently enabled the first-ever refereed publication to determine the temperature of lunar impact flashes – ranging from 1300 to 2800 C.

A modern approach to an ancient phenomenon

For at least a thousand years, people claim to have spotted flashes lighting up regions of the Moon, yet only recently have we had telescopes and cameras powerful enough to characterise the size, speed, and frequency of these events.

While our planet has lived with the risk, and reality, of bombardment from objects in space for as long as it has been in existence, we are now able to monitor our skies with more accuracy than ever before.

The NELIOTA project relies on funding from ESA’s Science programme, and is one exciting part of ESA’s Space Situational Awareness programme, which is building infrastructure in space and on the ground to improve our monitoring and understanding of potential Earth hazards.

The programme is currently in the process of setting up a network of Flyeye telescopes across the globe, to scan the skies for risky asteroids, including those that could hit the Moon.

In the future, ESA will move towards mitigation and active planetary defence, and is currently planning the ambitious Hera mission to test asteroid deflection.

Read more at the NELIOTA programme:




NEOCC Newsletter: December 2018

05 December 2018

The ESA SSA-NEO Coordination Centre has released the December newsletter summarising the most relevant data and events on asteroids and comets approaching the orbit of the Earth. Please, feel free to forward it to potentially interested people.

You can download the newsletter by clicking on the button below; to subscribe to the service, please fill in the form on page




Close Approach Fact Sheet


NEOCC Close Approach Fact Sheet: 2018 WV1

30 November 2018

The ESA SSA-NEO Coordination Centre has released a Close Approach Fact Sheet (CAFS) for asteroid 2018 WV1, passing by Earth on 02 December. Please, feel free to forward it to potentially interested people.

You can download the CAFS by clicking on the button below; for subscribing to our releases, please fill in the form on page





Andrea Milani (1948-2018)

29 November 2018

Andrea Milani, professor of mathematics at Pisa University, passed away unexpectedly last Wednesday while cycling near Pisa. With his deep knowledge and understanding on the Solar System dynamics, Andrea was a pioneer in a discipline started by him and a few others at the end of the past century: asteroid impact monitoring. His precursor activities at the end of the 1990s and beginning of this century were fundamental in establishing the first automated system to compute the probabilities that an asteroid could impact the Earth in the future. That information was made publicly available though the well known NEODyS service at the University of Pisa.

In line with those activities, he and some colleagues founded the SpaceDyS company in 2011, producing software for orbit determination and impact monitoring.

Shortly afterwards, Andrea promoted the creation at ESA of a centre to monitor NEOs, resulting in what today is our NEO Coordination Centre.

In the last 20 years, he has been a passionate advocate of the Planetary Defence discipline, in order to ensure that our society is prepared to face the threat posed by the near-Earth asteroids.

Sadly, our NEO community has certainly lost one of its key players.



Conference call

ESA NEO and Debris Detection Conference - Exploiting Synergies

22-24 January 2019

Registration is open for the ESA NEO and Debris Detection Conference - Exploiting Synergies, which will be held at ESA/ESOC, Darmstadt, Germany, 22 - 24 January 2019.

The deadline for the submission of abstracts is 1 October 2018.


The conference will highlight all classical and new disciplines of NEO and Debris Detection Research, including:

• Observation strategies - technology improvements of radar, passive optical, and laser systems
• Instrumentation component developments (CCDs, CMOS, ...)
• New telescope and radar projects (e.g. fly-eye telescope)
• Space-based observation concepts
• Space surveillance system architectures and applications
• Detection systems for fireball and other events
• Orbit prediction and determination
• On-orbit and re-entry risk assessments
• Data processing concepts
• Data exchange mechanisms and standardisation





Details on the conference venue, scope, registration, accommodation and abstract & paper submission can be found on the conference website.

We are looking forward to meeting you in Darmstadt!

With best regards from the local organisers,
Rüdiger Jehn and Tim Flohrer |
Robert-Bosch-Strasse 5,
64293 Darmstadt,

Programme committee:
Vladimir Agapov (ROSCOSMOS), Ricardo Bevilacqua (IAA), Nicolas Bobrinsky (ESA), Richard Crowther (UKSA), Pascal Faucher (CNES), Moriba Jah (University of Texas at Austin), Lindley Johnson (NASA), Stephan Mayer (FFG), Manuel Metz (DLR), Ettore Perozzi (ASI), Thomas Schildknecht (COSPAR), Makoto Yoshikawa (JAXA)


Download the call for papers: