November 2024 Newsletter

The first edition of the Planetary Defense Conference (PDC) managed by the International Academy of Astronautics happened exactly 10 years ago,in the week of 27-30 April 2009 (before the IAA became involved, there were two other PDCs, both in the USA). The conference was held in Granada, Spain, and was the first of a biennial IAA series that is continuing this month, with the 6th conference being held in College Park, USA.

September 2020 Newsletter

May 2023 Newsletter

March 2023 Newsletter

June 2023 Newsletter

September 2022 Newsletter

April 2021 Newsletter

February 2021 Newsletter

The month of December this year marks the fifth anniversary of the launch of ESA’s Gaia spacecraft. The mission, now operating continuously near the Earth-Sun L2 Lagrangian point, has already revolutionized many fields of astronomy, thanks to the broad and exquisite quality of the data it is producing.

December 2020 Newsletter

July 2020 Newsletter

June 2020 Newsletter

January 2021 Newsletter

April 2020 Newsletter

This year on 8 February marks the 50th anniversary of the fall of the Allende meteorite, the largest carbonaceous chondrite ever found. The atmospheric entry and impact happened at night local time, and were therefore well observed over the entire Northern Mexico. About 2 tonnes of fragments were later collected on ground in a strewn field of about 50 km size.

February 2020 Newsletter

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.

September 2015 Newsletter

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.

The closest approach distance is not the only important parameter for assessing the asteroid hazard. The velocity plays a crucial role in shaping the outcome of a close encounter as well as in evaluating the consequences of an impact. The speed at which an asteroid flies by the Earth results from geometrical and dynamical considerations characterizing its pre-encounter orbit.

The Fly-Eye Telescope is an innovative project of ESA‘s SSA-NEO Segment that will focus on survey and follow-up of NEOs. Another important milestone on the way to build the telescope was achieved: from 30 July to 1 August ESA attended the acceptance test of the equatorial mount at its production site in Verona, Italy.

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.

July 2022 Newsletter

The month of June 2002, 15 years ago, marked the kick-off of six parallel preliminary studies carried out by ESA’s General Studies Programme (GSP) in order to analyse possible asteroid missions. Three of those studies were devoted to in-orbit telescopes for NEO discovery and characterization, other two were devoted to asteroid rendezvous missions and finally one for asteroid rendezvous and impact.

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.

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.

For the first time in the history of NEA observations more than 2 000 new NEAs have been discovered in one calendar year, resulting in a monthly average of nearly 170 new asteroids. In addition, 2017 was the fifth year in a row with NEA discoveries above a thousand.

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.

Current NEO statistics About 4% of the known NEO population is in the risk list. This value has remained roughly constant over the past years even if the discovery rate has increased.

Two large objects have been observed in the month ofJuly. (85989) 1999 JD6 had a distant encounter with the Earth, while the newly discovered asteroid 2015 OL35 entered our priority list for follow-up observations.

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;

Some media attention was given to the distant fly-by of asteroid (1566) Icarus. Although the event in itself posed no collision threat whatsoever,Icarus is indeed an interesting object for the history of NEOs.

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.

April 2025 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.

On 1 February 2019 a bright daytime fireball was seen by multiple eyewitnesses around the area of Gulf of Mexico. It exploded over the western tip of Cuba, producing a significant shockwave felt by local residents, and the fall of a large number of stony meteorites, mostly near the village of Viflales.

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.

The number of known NEAs reached the round total of 20 000 at the end oflast month. This group of asteroids is steadily growing at a pace of roughly 160 new discoveries each month, thanks to the work done by the main asteroid surveys.

Ten years ago, on 6 October 2008,Richard Kowalski, an observer of the Catalina Sky Survey, spotted the first-ever asteroid found on an imminent collision course with the Earth. Over the following hours, hundreds of astrometric observations, plus light curves and spectroscopic data, were collected by observers all over the world.

March 2020 Newsletter