The quest to protect Earth from threatening asteroids is about to get a boost, as "an absolute flood of new observations" comes from a new telescope designed to scan the sky, says Ed Lu, co-founder of the B612 Foundation, and a nonprofit organization devoted to the planet's defense.
The Large Synoptic Survey Telescope (LSST) in Chile is expected to have "first light" in 2020, meaning that the telescope's mirrors will be exposed to the sky for the first time. Then full operations for its decade-long survey of the southern sky will begin in 2022, if all goes to plan. Lu and the others shared the latest developments in the planet's defense just in time for the Asteroid Day, the annual celebration on June 30 to discuss the science of asteroids and the possible threat they pose to Earth. While we know of no asteroids that will imminently cause damage to our planet, the possibility always exists, the participants said in an Asteroid Day teleconference on Thursday (June 27).
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Between LSST and other already operational telescopes, Lu added, scientists anticipate they will quickly catalog 70% or more of the asteroids or space rocks has more than 460 feet (1
Lu said scientists should start thinking about how to frame new discoveries to the public. When LSST first places these objects, their observations will be so sparse that it will be difficult to constrain the orbits of the asteroids. In the time before scientists are confident of these objects' paths, more of them could be seen as posing a threat to Earth simply because scientists can not get read on where they are moving in space
But smaller asteroids pose a threat too, just on a more local scale, said Mark Boslough – who was the first US the scientist to visit Chelyabinsk after a six-story object exploded over the Russian city in 2013. Even objects in the 130-foot (40m) range range could pose a threat to cities.
Boslough cited the Tunguska Event, and a 1908 incident in which an asteroid shattered in the Earth's atmosphere and flattened 830 square miles of Siberian forest. This and other "airbursts" are quite capable of causing a lot of property damage, so asteroids of a smaller size should also be included in disaster planning, he said.
"I've always thought we should be more concerned about those we are [now]primarily because they are just so much more abundant. "
Boslough – a physicist at Los Alamos National Laboratory – said these smaller objects should not be cataloged, because there are so many of them. Instead, he recommends developing surveys that would note that they are imminently hurtling towards Earth. Then disaster planners could evacuate the cities that could be under the threat of the object, just like we do today for incoming hurricanes
There are other opportunities to look for these objects as well. This summer, the Beta Taurid meteor stream from Comet Encke will be passing a bit closer to Earth than usual. This swarm of objects is in a 7-to-2 resonance with the planet Jupiter, meaning they orbit the sun seven times for every time that Jupiter orbits twice.
Telescopes will monitor the swarm for Tunguska-size objects in the coming weeks, because the swarm will be passing through our planet orbit in late June, and continuing through August, he said. He added that evoking Tunguska is not a coincidence, because this object was "more than likely a Beta Taurid" based on the timing of it hitting Earth on June 30, 1908.
Asteroid missions ongoing
Another aspect of planetary defense is studying near-Earth asteroids up close. NASA's OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) mission is in orbit at asteroid Bennu, and Japan's Hayabusa2 is circling asteroid Ryugu. In the next few years, both spacecraft are expected to deliver samples to Earth.
And there's more to come. Patrick Michel, the co-investigator of the forthcoming asteroid mission Hera, talked about the progress for that European asteroid mission. Hera is expected to launch in 2024 for the double asymmetric Didymos. What makes Hera unique from past missions, it will work in tandem with a NASA spacecraft called DART (Double Asteroid Redirection Test). DART will try to change the orbit of the moon of Didymos, and Hera will examine any DART leaves behind.
Hera is still in the planning stages and will go through another milestone milestone in November, Michel said. He added that it is an important milestone for the European Space Agency, because it may be "the only asteroid mission possibly done by Europe in the next decade."
But asteroids are not just dangerous – Marc Serres, CEO of the Luxembourg Space Agency. Since they contain water and minerals – resources that can be used for space missions – he said the time to generate a catalog is now before we begin exploring the solar system. As people begin to move to the moon and other destinations, he said, it will be important to me as much as we can.
"Using the resources we can find in space will completely revolutionize the way we act in space, because we do not need to bring everything with us, "he said.