Frequently Asked Questions

Frequently Asked Questions about NEOs and the NEOShield Project

Below are some FAQs. If you have other questions please contact us and we will try to help, as well as update this list.

For explanations of specific terms, see the Glossary.

General NEO FAQs
NEOShield Project FAQs

General NEO FAQs

When is the next big impact likely to happen?

    It is all a question of probabilities. As you can see in the table here, small impacts happen rather often, with big impacts that would cause major damage every several thousand to millions of years. But the impact frequency is an average. Therefore, even though the Tunguska impact in Siberia was in 1908, that doesn't mean that the next 50m asteroid will impact in 3908. It is an average, based on analyses of the known and expected NEO populations. There is no substitute for observation campaigns designed to detect and monitor NEOs.

If an asteroid was discovered now, how long would it take to plan a mission like the ones discussed here?

    The planning and implementation of a mission depends on its complexity and the amount of resources available to implement it, as well as the amount of risk that is willing to be accepted for a mission failure. For a mission of this complexity implemented through the standard (e.g. ESA or NASA) processes, a development time of 6-10 years would be normal. However, the NEOShield project will perform a lot of the initial mission design and planning work, so that a mission could be implemented faster if a threat were detected. Also, if a demonstration mission were to be implemented following the current NEOShield project, there would be less time required in future to develop and test critical technologies, further reducing the time required. The exact development roadmap will be analysed during the current NEOShield project. Watch this space.

How are NEOs and PHOs tracked and will we see one in time to plan to deflect it?

    NEOs and PHOs are tracked mainly by ground-based observatories. There are networks of mainly optical telescopes, but also radar telescopes, around the world. Amateur astronomers also make a significant contribution to the discovery and tracking of NEOs.
    There are some space-based observatories, however there are arguments for funding a new, dedicated, NEO survey spacecraft.
    The Minor Planet Center gathers and analyses the new findings.
    In general, large NEOs, which are the dangerous ones, are discovered with sufficient warning to prepare for a mitigation method, however some NEOs are not observable, as they may be for example on the other side of the Sun from Earth.  This is an argument for a NEO-observation spacecraft that would be placed in an orbit closer to the Sun that could survey all sides of the Solar System.

Is there a risk that the nuclear solution could lead to a weaponisation of space?

    No. The nuclear solution will only be used if it is absolutely necessary, and if so the mitigation attempt would probably be controlled by a multinational organisation such as the UN. The political structures are also currently being put in place, by the UN as well as through the NEOShield Project.

What are NEOs made of?

    Asteroids are essentially rocky small bodies. The asteroids are often divided into different classes based on their material composition. Most common are C-type, which are carbon-rich and darker asteroids, and S-type, which are silica rich stony asteroids and slightly lighter. There are also asteroids that have a higher metallic content.
    Comets are usually rocky cores with ice around them. It is the melting of this ice streaming behind comets that gives them their well-known tails.

What is the naming convention for Asteroids?

    Asteroids and Comets are named by committees of the International Astronomical Union (IAU). The discoverer can suggest a name to these committees. 
    However, most asteroids only have provisional names. The convention for theses is that the first four digits are the year of discovery, followed by a space, followed by a letter representing the half month within that year in which it was discovered, followed by another letter representing the order of discovery within that half month. If there is a number after the second letter, it represents the number of times that the second letter has been repeated in that half month.  For example, 2005 GO21 was discovered in the 7th half month of 2005 (G is the seventh letter), and was the 539th new asteroid named in that half month (21 repetitions of the alphabet and then O is the 14th letter, without "I").

Why are the total number of NEOs and PHAs different on different websites?

    Different organisations use different definitions for both NEO and PHA. The size is usually calculated from the Absolute Magnitude, however this method is often approximate. Also, make sure that you are comparing numbers from the same dates, as new NEOs are always being discovered!

NEOShield Project FAQs

How long will the project last?

    NEOShield is a three and a half year project, running until the middle of 2015, but a proposal will be made to build a demonstration mission after that.

Who is involved in the NEOShield project?

    Please visit our Partners page for information on the project team.