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NASA needs a camera to detect killer asteroids – quartz



Astronomers are usually patient people. When it comes to stars, much of what they did millions of years ago happened, and when it comes to space probes, even pre-launch preparation can take a decade or more.

But they become impatient when they launch an infrared space telescope called NEOCam. It has a very specific mission: to explore objects close to the Earth – astronomical bodies, mostly asteroids, whose orbits around the Sun might get close to Earth and possibly collide with our planet, some of which could damage or destroy civilization itself.

It is not speculative. a great meteoric influence is inevitable, and we need to keep an eye on the solar system.

"The question is, when will the next happen on a human timescale and on a geological time scale?" says Amy Mainzer, a scientist at the Jet Propulsion Laboratory of CalTech and the lead investigator of the NEOCam project.

It's not that the US government is not interested. NASA has already cataloged all near-Earth asteroids more than 1 km in diameter, and in 2005 the Congress passed a law requiring NASA to find 90% of near-Earth objects over 140 meters in diameter

One of the largest, well-documented asteroid air strikes in 1908 over Tunguska, Russia, landed 2,000 km² of forest. Scientists believe it had a diameter of 40 to 60 meters.

The Space Agency had a deadline of 2020 to find these near-Earth objects. It will not make it. In June 2018, NASA's Planetary Defense Officer Lindley Smith announced that about 8,000 such objects had been discovered. However, scientists expect that twice as many are undetected. To illustrate the urgency, Smith then said that if any of these unknown objects posed a threat to Earth, sending a spacecraft would require a 10-year warning.

There is still no plan to meet the Congress mandate. NASA says it is waiting for a panel from the National Science Foundation (NSF) to complete a study on the best methods of locating objects near Earth that are expected this spring before deciding on NEOCam.

You do not lose your sleep because of the risk of an undiscovered asteroid acting on Earth because of the low chances, but they are not zero, "says MIT planetary scientist Richard Binzel, who is not part of the NEOCam team, but it has been spoken out for the NSF panel. "We have the ability, the responsibility of an adult, to simply know what's out there. And NEOCam is basically ready to use.

Another space probe called IMAP will be launched in 2024 to study solar wind, which is also suitable for NEOCam. There is room for another payload on the rocket, and asteroid researchers say this is the best opportunity to launch NEOCam, which Maizer first proposed in 2005 and refined for 14 years. However, they will soon need a license and funding to build the telescope in a timely manner.

Another important source of near-earth object data will be the Large Synoptic Survey Telescope (LSST). It is funded by the NSF and will install a mirror in the form of tennis courts on a mountain in Chile. By 2023, the telescope will begin with a ten-year survey, which will often produce large format footage of the night sky. Asteroid researchers expect to gather enough data to find about 75% of the NEO objects with a diameter of 140 meters or more.

But achieving the 90 percent mandate requires space-based infrared observations – just like the ones NEOCam is supposed to collect. Infrared observations can do something that a ground telescope can not do: estimate the size of an asteroid. At visual wavelengths, astronomers find it difficult to distinguish between large, dark and small, bright objects, but infrared data can be used to solve this problem. This is especially important when LSST starts its work.

"I do not think anyone appreciates the hustle and bustle of the early part of [LSST Survey] when we start to see everything out there," says Binzel. "A 10-meter object orbits every week in the orbit of the Moon – and we'll see years and years of these" incoming "objects well before their close approach. The early orbit solutions will not be able to distinguish between hits and failures. We need to focus our attention on the largest objects in this incoming flow – and we need the characterization of IR [infrared] to find out. [19659002] A Fold in NEOCam's Plan is the work of Nathan Myhrvold, a physicist and former Microsoft manager, who has published research that argues that NASA data on near-Earth objects is more uncertain than their collectors believe partly because the source of this data, a space telescope called NEOWISE, was not originally intended to find objects so close to our planet 19659002] Mainzer, who is also the Chief Investigator of NEOWISE, says Myhrvold's analysis is and the asteroid data was confirmed against independent data and models by other independent researchers, and NEOCam has been optimized for detecting objects near Earth using special imaging chips that have been refined high-resolution infrared images at a temperature of 40 ° K (about -387 ° F) record, which is compared to toasty WISE chips, which at 8 ° K were operated. In this way, NEOCam can collect data over a longer period of time.

Apart from importing into civilization, the collection of asteroid data could serve other purposes for NASA. By cataloging asteroids, the agency – and its growing number of commercial partners – could set targets for future space missions, and public opinion polls suggest that Americans prefer NASA to spend more time asteroiding than for example sending people to Mars.
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