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Flyeye Telescope in ESA's SSA Program for NEO (Near Earth Object) Detection

Asteroid Impact Exercise     ESA Coordinates Efforts    Space Safety     References

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. As part of the global effort to hunt out risky celestial objects such as asteroids and comets, ESA is developing an automated telescope for nightly sky surveys. 1)

This telescope is the first in a future network that would completely scan the sky and automatically identify possible new near-Earth objects, or NEOs, for follow up and later checking by human researchers. But a web of traditional telescopes would be complex and expensive because of the number required. Adding to the problem, the system must be able to discover objects many times fainter than the naked eye can perceive.

While no network can spot all potentially hazardous objects, under favorable conditions it should detect everything down to about 40 m in diameter at least three weeks before impact.

The answer is a new, European telescope nicknamed ‘Flyeye’ that splits the image into 16 smaller subimages to expand the field of view, similar to the technique exploited by a fly’s compound eye.

The design is modular, and allows for mass and cheaper production and lower maintenance costs. It will be used to build the prototype, to be fielded by ESA’s Space Situational Awareness (SSA) program. “This novel technology is key to the future NEO survey network,” says Gian Maria Pinna of the SSA office.

Performance equivalent to large telescope

In the telescope, a single mirror of 1 m equivalent aperture collects the light from the entire 6.7º x 6.7º field of view [about 45 square degrees; 6.7º is about 13 times the diameter of the Moon as seen from the Earth (roughly 0.5º)] and feeds a pyramid-shaped beam splitter with 16 facets. The complete field of view is then imaged by 16 separate cameras. The red caps in the image are the covers over the 16 cameras that contain the 16 detectors. The tubes contain a set of secondary lenses.

“The new telescopes would provide the resolution necessary to determine the orbits of any detected objects,” says Gian Maria. “If the prototype confirms the expected performance, it will pave the way to full procurement and deployment of the operational network of telescopes.”

In the summer of 2014, ESA signed a contract for about €1 million with a consortium led by CGS S.p.A (Italy), comprising Creotech Instruments S.A. (Poland), SC EnviroScopY SRL (Romania) and Pro Optica S.A. (Romania) for the detailed design of the advanced telescope. 2)

It is expected that the detailed design will be followed by several additional contracts with European companies valued at up to €10 million for building and deploying the first survey prototype telescope.

“The development of the first optical sensor specific to ESA’s NEO search and discovery activities is a fundamental step toward Europe’s contribution to safeguarding our planet from possible collisions by dangerous objects,” notes Nicolas Bobrinsky, Head of the SSA Program.

The first Flyeye telescope is expected to be ready for installation at its final location on Mount Mufara in Sicily at the end of 2019.


Figure 1: Artist's rendition of the Flyeye telescope spotting an asteroid in the night sky (image credit: ESA, A. Baker) 3)

Flyeye Telescope


Figure 2: Artist's view of the ground-based Flyeye telescope on Mount Mufara in Sicily (image credit: ESA, A. Baker, CC BY-SA 3.0 IGO) 4)


Figure 3: Schematic view of the Flyeye telescope design (image credit: ESA, A. Baker)

ESA’s automated Flyeye telescope will help Europe discover risky celestial objects such as asteroids and comets during its nightly sky surveys. It will automatically identify possible new near-Earth objects for follow up and later checking by human researchers as part of Europe’s SSA (Space Situational Awareness) Program. 5)


Figure 4: The equatorial mount that will hold the Flyeye telescope orients the direction of view around the right ascension and the declination axis – the celestial coordinates. By doing so, it compensates for the rotation of the Earth by movement of one axis only and avoids image rotation during exposures (image credit: OHB Italia)

Legend to Figure 4: The black structure at the center of the mount in this picture is for testing purposes and will be replaced with the Flyeye telescope. The mount and telescope are now being integrated in Milan, Italy, by OHB Italia ready for installation at the final location on Mount Mufara in Sicily at the end of 2019.


Figure 5: The Flyeye telescope infographic illustrates how ESA will use first-ever ‘flyeye’ telescopes to support the UN and international efforts to respond to asteroid risks (ESA) 6)

ESA is developing new ‘flyeye’ telescopes to conduct automated nightly sky surveys. Up to four Flyeye Telescopes will be located worldwide. Together with sightings from European and international astronomers, Flyeye data will be sent to the IAU (International Astronomical Union) Minor Planet Center (USA), the world’s central clearing house for all asteroid sightings.

ESA asteroid experts work with other space agencies and European civil protection authorities to devise mitigation measures. ESA also supports asteroid warning and risk assessment activities at the United Nations, in cooperation with experts from the IAU and worldwide.

Asteroid Impact Exercise

• 19 June 2019: ESA will be participating in this year’s Asteroid Day, the UN-endorsed global awareness campaign day on the small rocky bodies scattered across space, taking place on Sunday, 30 June. 7)

- The Agency will share with media and public its various activities related to asteroids, which it regards as a vital subject for scientific study, as ‘time capsules’ from early in the history of the Solar System and the birth of the planets.

- Asteroids have influenced Earth’s development, as seen by the millions of impact craters scarring our world. They are also a promising source of future resources and – last but not least – they pose a proven threat to Earth and human civilization. ESA is taking action as part of an international effort to mitigate this risk.

- Over the last two decades, ESA has been performing detection and analysis of asteroids whose orbits bring them close to Earth, known as near-Earth objects (NEOs). There are an estimated 10,000,000 NEOs out there larger than 10 m – the threshold above which damage on the ground could happen.

- As part of its space safety activities, ESA coordinates observatories and astronomers worldwide through its NEO Coordination Center, located at ESA’s ESRIN facility in Italy.

- Building on this experience, ESA has developed a new type of automated telescope for nightly sky surveys. This ‘Flyeye’ telescope splits its image into 16 smaller subimages to expand the field of view, similar to the technique exploited by a fly’s compound eye.

- A network of these Flyeye telescopes would completely scan the sky and automatically identify possible NEOs for follow up and later checking by human researchers.

- The first Flyeye telescope is being installed atop the 1865-m Monte Mufara mountain in Sicily; the same island where the very first asteroid was discovered back in 1801.

- A network of Flyeye telescopes is being proposed for approval by Europe’s space ministers at Space19+ this November as part of ESA’s Space Safety initiative.

• 29 April 2019: In a fictional dramatization, ESA has been monitoring an asteroid en route to strike Earth, although a crucial piece of information - where it might hit - is not yet clear. It’s the year 2028, and the European Space Agency has been carefully monitoring a worrying situation: an enormous asteroid is en route to strike Earth, although the exact point of impact is not yet clear. 8)

- National governments are planning to evacuate millions of people, an undertaking that will cause untold human misery and disruption on a gigantic scale. If the asteroid’s impact zone can be fixed, perhaps such chaos can be avoided.

- As precious hours pass, find out how ESA’s Planetary Defence Office is able to obtain crucial information on this potential disaster as part of the Agency’s Space Safety activities.

- Back to the present day: Find out more about how ESA is preparing to protect our pale blue dot, its inhabitants and the vital satellite systems on which we have become so dependent.

Figure 6: Asteroid impact 2028: Protecting our planet (video credit: ESA)

• 26 April 2019: For the first time, ESA will cover a major international asteroid impact exercise live via social media, highlighting the the actions that might be taken by scientists, space agencies and civil protection organizations. 9)

- Every two years, asteroid experts from across the globe come together to simulate a fictional but plausible imminent asteroid impact on Earth. During the week-long scenario, participants – playing roles such as ‘national government’, ‘space agency’, ‘astronomer’ and ‘civil protection office’ – don't know how the situation will evolve from one day to the next, and must make plans based on the daily updates they are given.

- For the first time, ESA will cover progress of the hypothetical impact scenario from 29 April to 3 May live via social media, primarily via the @esaoperations Twitter channel.

- The exercise is being produced by experts from NASA's Planetary Defence Coordination Office working together with the US Federal Emergency Management Agency at the 2019 Planetary Defense Conference, Washington DC. The conference is the world’s most important gathering of asteroid experts, and is strongly supported by ESA, NASA and other agencies, organizations and scientific institutions.

- “The first step in protecting our planet is knowing what’s out there,” says Rüdiger Jehn, ESA’s Head of Planetary Defence.

- “Only then, with enough warning, can we take the steps needed to prevent an asteroid strike altogether, or to minimize the damage it does on the ground.”

20,000 asteroid milestone

- As of April 2019, 20,000 asteroids whose orbit brings them near Earth have been found. At the current rate of roughly 150 new discoveries every month, this number is set to rapidly increase.

- With the planned deployments of ESA’s new Flyeye and Test-Bed Telescopes, Europe’s ability to discover, confirm and understand the ancient rocks that hurtle through space will grow – fundamental to implementing mitigation measures.

Figure 7: Visualization of asteroid Itokawa. This artist’s impression, based on detailed spacecraft observations, shows the strange peanut-shaped asteroid Itokawa. By making exquisitely precise timing measurements using ESO’s New Technology Telescope a team of astronomers has found that different parts of this asteroid have different densities. As well as revealing secrets about the asteroid’s formation, finding out what lies below the surface of asteroids may also shed light on what happens when bodies collide in the Solar System, and provide clues about how planets form [video credit: JAXA, ESO/L. Calçada/M. Kornmesser/Nick Risinger (,Published on 26 April 2017]

Follow asteroid impact exercise live

- The @esaoperations Twitter channel will share updates on the asteroid impact exercise in realtime, including daily press releases revealing how the asteroid impact scenario will evolve, so followers will find out the ‘news’ as the experts do.


Figure 8: Estimated risk corridor for the impact of a hypothetical asteroid. The graphic is showing the hypothetical impact risk corridor of asteroid 2019 PDC (Planetary Defense Conference), when its orbit is still not fully known (image credit: 2019 PDC Exercise)

Legend to Figure 8: The asteroid’s uncertainty region at the time of the potential impact is much longer than the diameter of the Earth, but its width is only about 70 km (45 miles). The intersection of the uncertainty region with the Earth creates a so-called “risk corridor” across the surface of the Earth. The corridor wraps more than halfway around the globe, spanning from the Hawaii on the western end, across the US and Atlantic Ocean, and all the way to central and southern Africa on the eastern end. The red dots on the Google Earth image trace the risk corridor.

On ESA Facebook, join us for two live-stream videos straight from the Planetary Defense Conference. The first will be on Sunday, 28 April, at 14:00 CEST (08:00 EDT) with Rüdiger Jehn, ESA’s Head of Planetary Defence, and the second on Thursday, 2 May, at around mid-afternoon European time.

For daily updates on the asteroid impact scenario, check out “Rolling coverage: Brace for hypothetical asteroid impact”, beginning on the first day of the conference, Monday, 29 April, over on ESA's Rocket Science blog.

Asteroid 2019 PDC hypothetical impact scenario: The scene has been set for this year’s hypothetical impact scenario. Although realistic, it is completely fictional and does not describe an actual asteroid impact.

• An asteroid was discovered on 26 March 2019 and was given the name '2019 PDC' by the Minor Planet Center.

• Very little is known about this newly discovered asteroid’s physical properties. With a magnitude (brightness) of 21.1 – invisible to the naked eye but viewable by professional astronomers – it has been classed as a ‘Potentially Hazardous Asteroid’, and experts have determined its average size could be anywhere from 100-300 meters.

• The day after 2019 PDC was discovered, ESA and NASA’s ‘impact monitoring systems’ identified several future dates when the asteroid could hit Earth. At this early stage, with not many observations yet recorded, both systems agreed that the asteroid was most likely to strike on 29 April 2027 – more than eight years away – with a probability of impact of about 1 in 50,000.

• Astronomers continued to monitor the asteroid for a month after its initial detection, which provided them more information about the object’s trajectory, and have now discovered that the chance of impact is rapidly increasing. By 29 April 2019, (the first day of the Planetary Defence Conference), the probability of impact has risen to 1 in 100.

ESA coordinates European efforts

The 2019 Planetary Defence Conference will be the sixth such conference that the International Academy of Astronautics (IAA) has held; and ESA has been closely involved with all of them.

As in previous years, ESA is sponsoring the event and providing a conference co-chair. A large team of ESA experts will also be present, including members of the Agency’s Near-Earth Object Coordination Center and the Hera asteroid deflection mission.

During the hypothetical asteroid impact scenario, ESA experts will participate in discussions on the possible risks posed by asteroid 2019 PDC, and what responses could be considered.

“Fortunately, impacts from medium and large asteroids are not very common,” explains Detlef Koschny, senior asteroid expert at ESA who will be involved in the hypothetical scenario.”

“However, this means we have little opportunity to practise our response to this very real – though unlikely – danger. This year’s impact scenario is a very unique chance to run through, in real-time, an asteroid impact.”


Figure 9: ESA's planned Hera mission will test asteroid deflection techniques. Using its laser altimeter Hera scans Didymoon's surface. ESA’s Hera mission concept, currently under study, would be humanity’s first mission to a binary asteroid: the 780 m-diameter Didymos is accompanied by a 160 m-diameter secondary body (image credit: ESA -

Space Safety at ESA

Solar activity, asteroids and artificial space debris all pose threats to our planet and our use of space.

SA's Space Safety activities aim to safeguard society and the critical satellites on which we depend, identifying and mitigating threats from space through projects such as the Flyeye telescopes, the Lagrange space weather mission and the Hera asteroid mission.

As asteroid experts meet for the international Planetary Defense Conference, ESA is focusing on the threat we face from space rocks. How likely is an asteroid impact? What is ESA doing to mitigate impact risks? Follow the hashtag #PlanetaryDefense to find out more.


Figure 10: As we discover more about the brilliant scale and nature of the Universe, planet Earth’s blue oceans, green forests and glistening city lights appear even more unique, and even more fragile. Many hazards have been identified originating in space, which although unlikely, continue to pose real dangers to our way of life, and in the worst cases to human health and safety. Only in the past decades have we had the opportunity to understand the potential perils of our position in our Solar System, and as technologies continue to advance we are entering a period in which we can actually act. However, as technologies advance, so too does our dependence on them, making us more vulnerable to both human-made and natural threats in space. Find out more about ESA's space safety and security activities, here (image credit: ESA)

1) ”ESA’s bug-eyed telescope to spot risky asteroids,” ESA, 10 September 2014, URL:

2) ”CGS awarded ESA Contract for NEOSTEL – July 2014,” CGS, July 2014, URL:

3) ”Flyeye telescope,” ESA, 27 October 2016, URL:

4) ”Flyeye Observatory,” ESA, 14 Feb. 2017, URL:

5) ”Steady Pointing,” ESA, 03 May 2018, URL:

6) ”Flyeye telescopes infographic,” ESA operations image of the week, 14 June 2018, URL:

7) ”ESA celebrates Asteroid Day on 30 June,” ESA, 19 June 2019, URL:

8) ”Asteroid impact 2028: Protecting our planet,” ESA, Asteroid impact 2028, 29 April 2019, URL:

9) ”The day the asteroid might hit,” ESA, 26 April 2019, URL:

The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: ”Observation of the Earth and Its Environment: Survey of Missions and Sensors” (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (

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