According to statistics, asteroids of this size collide with Earth approximately every 50-100 years. Larger asteroids are much rarer, but – ask the dinosaurs – they do much more damage. Fortunately, they are much easier to detect. In fact, we have discovered almost all asteroids larger than 1 km. Small to medium-sized asteroids are more common and can still cause a lot of damage, but a few days of warning may be enough for local officials to tell the public to stay away from windows and even evacuate the area.

We will be ready with NEOMIR

ESA’s NEOMIR will fill a gap in our current asteroid detection capabilities, whether it’s preparing for a mission to deflect a large asteroid years ago, or providing data to local authorities to inform communities about aerial flares weeks in advance.

Asteroids appear because they reflect sunlight that we can detect from Earth. But the closer you get to the Sun, the harder it is to see them. Asteroids passing through the Sun’s surface are particularly difficult to detect, but we also cannot see asteroids near the Sun from Earth because they are obscured by their brightness. Lagrangian points are places in space where the gravity from the Earth equals the gravity from the Sun, and satellites may be in lower “orbit maintenance” than those orbiting the Earth or flying into deep space. Copyright: ESA

ESA’s future NEOMIR mission will orbit around the first Lagrangian point (L1) between the Sun and Earth and remain in the same position relative to the two bodies. This will allow the telescope to see asteroids that may approach Earth from the Sun.

NEOMIR will observe a tight ring around the Sun, unobservable from Earth, from outside Earth’s corrupted atmosphere and using an infrared telescope. By observing in the infrared part of the light spectrum, NEOMIR will detect heat from asteroids emitted by the asteroids themselves, not drowned out by sunlight. This thermal radiation is absorbed by Earth’s atmosphere, but NEOMIR will be able to see the Sun from space closer than it can from Earth.

Asteroids 20 meters (66 feet) or larger heading toward Earth must be detected by NEOMIR at least three weeks in advance. In the worst-case scenario, when an asteroid is detected passing near a spacecraft, we get at least a three-day warning – that’s the fastest time an asteroid can travel from L1 to Earth.

The current situation

Details of the Space Security Program’s NEOMIR mission are currently being finalized and are scheduled to launch on an Ariane 6-2 rocket around 2030.

The initial study to assess the feasibility of the NEOMIR mission was conducted in 2021 by ESA’s Concurrent Design Facility in the Netherlands. Research focused on identifying a mission to complement NASA’s NEO Surveyor mission. The US-funded mission is to fulfill the mandate of the US congress to detect 90% of near-Earth objects greater than 140 meters (460 feet) in diameter; NEOMIR is designed to focus on close strikes of all sizes.

NEOMIR is currently in the early stages of mission work. This would require a half-meter telescope with a large corrected focal plane, as well as two infrared channels covering light in the 5-10 micrometer wavelength range. The detector technologies and related electronics required for this new mission are currently under development. In parallel, industrial research and development projects are planned as ancillary measures.