Astronomers are usually patient people. When it comes to stars, many of what they are researching happened millions of years ago, and when it comes to space probes, even pre-launch prep can take ten years or more.
But they become impatient about launching an infrared space telescope called NEOCam. It has a very specific mission: locating near-earth objects: astronomical bodies, usually asteroids, whose orbits around the sun can come close to the earth and possibly collide with our planet, some of which can damage or destroy civilization itself.
It is not speculative; a major meteoric impact is inevitable and we must keep a closer eye on the solar system.
"The question is, when will the next take place on a human scale and in a geological time scale?" Says Amy Mainzer, scientist at the CalTech Jet Propulsion Laboratory and the principal investigator of the NEOCam project.
It is not that the US government is not interested. NASA has already cataloged nearby asteroids that are larger than 1 km (diameter) and Congress adopted a law in 2005 requiring NASA to find 90% of near-earth objects larger than 140 meters (460 ft) in diameter .
One of the largest well-documented asteroid air storms, across Tunguska, Russia, in 1908, cleared 2,000 square kilometers of forest. Scientists think it has a diameter of 40 to 60 meters.
The space agency was given a 2020 deadline to find these near-earth objects. It doesn't make it. In June 2018, NASA planetary defense officer Lindley Smith said about 8,000 such objects have been detected, but scientists expect twice as many are still undetected. To illustrate the urgency, Smith then said that if one of those unknown objects is a danger to Earth, sending a spacecraft to intercept it would require a 10-year warning.
There is still no plan to fulfill the mandate of Congress. NASA says it is waiting for a panel at the National Science Foundation (NSF) to finalize a study of the best methods to find near-earth objects expected sometime in the spring before it makes its decision about NEOCam.
"I am not losing sleep because of the risk of an undiscovered asteroid affecting the Earth because the odds are small but they are not zero," says MIT planetary scientist Richard Binzel, who is not part of the NEOCam team, but arguments for its necessity for the NSF panel. "We have the ability, the responsibility for adults, to easily know what's beyond. And NEOCam is basically ready for use."
Another space probe called IMAP starts in 2024 to study solar wind, en route to a job that is also ideal for NEOCam. There is room on his rocket for an additional payload, and asteroid researchers say this is the best opportunity to launch NEOCam, which Maizer first proposed in 2005 and refined for 14 years. But they will soon need approval and financing to build the telescope on time.
Another important source of near-Earth object data is the Large Synoptic Survey Telescope or LSST. Funded by the NSF, it will install a large mirror on the tennis court on a mountain in Chile. By 2023, the telescope will begin a ten-year study that repeatedly captures widescreen images of the night sky. Asteroid researchers expect it to collect enough data to find around 75% of NEO objects of 140 meters or more.
However, to achieve the 90% mandate, space-based infrared observations are required, such as those for which NEOCam is intended. Infrared observations can do something that a telescope cannot do on the ground: estimate the size of an asteroid. At visual wavelengths, astronomers struggle to distinguish between large, dark objects and small, clear objects, but infrared data can be used to solve that problem. That will be especially important when the LSST starts working.
"I don't think anyone appreciates how hectic the early part of the [LSST Survey] will be, when we begin to see everything there is, "Binzel says." A 10-meter object passes every week within the orbit of the moon – and we will begin seeing years and years-value of this & # 39; incoming & # 39; objects well before their approach. The solutions for the early job will be & # 39; hit or miss & # 39; cannot distinguish. We need to focus our attention on the largest objects in that incoming flux – and we need the IR [infrared] characterization to find out. "
A wrinkle in NEOCams plan is the work of Nathan Myhrvold, a physicist and former Microsoft CEO. He published research in which he claimed that NASA data about objects near the earth are more uncertain than collectors think, partly because the source of that data, a space telescope called NEOWISE, was not originally designed to spot objects so close to our planet layers.
Mainzer, who is also the main investigator of NEOWISE, says Myhrvold's analysis is flawed and that the asteroid data has been confirmed by independent investigators using independent data and models. And NEOCam is optimized for spotting near-earth objects, with specialized imaging chips refined for recording high-resolution infrared images at a temperature of 40 ° K, around -387 ° F, which is pleasant compared to WISE & # 39; s chips, operating at 8 ° K. This allows NEOCam to collect data for a much longer period.
Beyond import to civilization, collecting asteroid data could serve other purposes for NASA. Asteroid cataloging could provide the agency – and the growing number of commercial partners – with targets for future space missions, and opinion polls suggest that Americans would prefer NASA to spend more time creating asteroid effects than sending people to Mars, for example.