Coming soon: more telescopes to discover asteroids
In the coming years, the American space agency, NASA, is expected to store piles of data on near-Earth celestial bodies (NEOs), including asteroids and comets. Unfortunately, there is nothing to protect us from a meteor similar in size to the one that crossed the skies of the Russian city of Chelyabinsk (see below) in February 2013, injuring more than 1000 people. The diameter of the bone was 17 meters, too small to be detected by any systematic scanning. Asteroid detectors naturally concentrate on larger objects, the ones that hit harder. Fortunately, impacts of a similar magnitude to the Chelyabinsk impact happen once every century, so perhaps humans will be able to perfect their prediction techniques by the time the next impact occurs.
Here is an overview of some of the best tools available to researchers today for detecting and protecting against asteroids:
Since the middle of the previous decade, the "Catalina" survey has been the main project for the discovery of NEOs, and today it discovers about 600 such sky grams per year with the help of observatories in Arizona and Australia. The project helped NASA reach the goal of cataloging 90% of the NEOs whose diameter exceeds one kilometer.
Not long ago, the first of the four facilities in the planned Pan-STARRS array began broadcasting from Hawaii. The array, which stands for "panoramic survey telescope and rapid response system" is already the second largest NEO discovery project in terms of the number of objects discovered per year. It can be assumed that it will help in the discovery of many asteroids with a diameter of several hundred meters, but most objects smaller than that will also remain outside its range.
The "Large Synoptic Survey Telescope" (LSST), whose construction will be completed in Chile at the end of the decade according to the plan, will be a powerful survey tool. The telescope, whose mirror diameter is 8.4 meters, will be equipped with a digital camera with a resolution of three giga-pixels, and will eventually pick up the vast majority of much smaller objects, 140 meters in diameter and more. In doing so, it will achieve NASA's next asteroid discovery goal.
The "Last Warning System Before an Asteroid Hits the Earth" (ATLAS), whose completion is expected in 2015, is designed to provide a warning time long enough to evacuate areas expected to be hit by an asteroid. The system planners estimate that an array of small telescopes that will be placed in Hawaii will be able to detect a "city-destroying" asteroid with a diameter of 50 meters about a week before its possible impact.
The non-profit organization B612 Foundation recently removed the lot from its plans to build a space telescope called Sentinel, which will scan the inner regions of the solar system while sailing in an orbit similar to the orbit of Venus. It will be launched in 2018 and should provide immediate information about the really dangerous asteroids in the area. The goal is to catalog 90% of the NEOs whose diameter is greater than 140 meters in the 5.5 years of its activity.
