Discovery & Preparation supported a study that explored using star trackers – already on board many spacecraft for orientation calculation – to search for NEOs.Īnother challenge we face from extraterrestrial objects is that dust on their surfaces may affect visiting spacecraft, landers and astronauts. To mitigate this threat, the first step is to search for NEOs and map their orbits. Several Discovery & Preparation studies have investigated different elements of possible future missions to explore small extraterrestrial objects.Īsteroids and comets whose orbits come close to or even cross that of Earth are known as near-Earth objects ( NEOs), and they can pose an impact threat. Laying the groundwork for ESA’s future activities, Discovery & Preparation supports exploratory research into new concepts. For all these reasons, and many more, it is important to study these objects and find out more about them. Such objects may also have brought organic matter to other planets and moons, some of which – Jupiter’s moon Europa or Saturn’s moon Enceladus, for example – may possess the right conditions for hosting some form of life. Such collisions were more common in the early Solar System, but small objects can still impact Earth, damaging life, nature and infrastructure. What’s more, these objects may have played a vital role in the development of our planet and terrestrial life by colliding with Earth in catastrophic impact events, bringing life-sparking organic compounds.

Asteroids and comets are believed to be leftover debris from the formation of the Solar System, meaning they can help trace its history.

Comet vs asteroid