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Earth will soon lose a key tool in the fight to spot potentially dangerous asteroids – and NASA has decided to fund a custom replacement.
NASA wants to build a space telescope to monitor the sky in infrared light, which would be a boost in its asteroid identification and tracking program in the immediate vicinity of the Earth. These activities are the cornerstone of planetary defense, and the direction of NASA's science mission have created a separate budget, worth $ 150 million for the current fiscal year, in the budget, for the global defense, announced the ### Agency today (23 September).
This budget line is intended to increase flexibility and responsiveness in global defense, said Thomas Zurbuchen, associate director of the Science Mission Directorate, at a meeting of the Planetary Science Advisory Committee in Washington. . "The goal is not to do everything for eternity," he said. "The goal is to do the right things as they appear."
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For now, the good thing, according to Zurbuchen, is to build a new space telescope capable of detecting and tracking objects close to Earth: the NASA Reaction Propulsion Laboratory will lead the project. Mr Zurbuchen said the new instrument could be launched as early as 2025, although he stressed that it was not an official deadline, which would depend on the amount of funding received by the program.
The new initiative is strongly based on a project called NEOCam, a concept of mission that the global defense community has been discussing for years. NEOCam was formally proposed as a scientific mission, but was not selected for funding, in a decision that Zurbuchen today called "one of the biggest failures I've ever seen. have committed in my work ".
When the NEOCam proposal was first considered, it was examined in the context of science and not of global defense. And although asteroids are interested in both sides of the fracture, they need different types of information. Scientists want a statistical sampleThey do not need to see all the asteroids, they just want to get an idea of what the asteroids are.
Planetary defense is very different: these experts must see every object that is perceptible and understand precisely where it is and where it is going. Ideally, scientists should also know the size and structure of each object. Indeed, if a the asteroid is indeed a threatThese factors determine the impact of an impact.
Zurbuchen said today that the new budget system responds to this distinction by putting global defense in competition with science. He also confirmed that the new NASA telescope would be closely inspired by the NEOCam project.
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NEOCam itself has its roots in the NEOWISE project, which is the second life of a former astrophysics mission called Wide field infrared survey explorer. The telescope focused on asteroids in 2013 under the new name NEOWISE. Since then, the telescope has spotted tens of thousands of space rocks, 135 of which are traveling in the immediate vicinity of the Earth.
But the success of NEOWISE in his second career was due to luck, not to design, and luck runs out. "This has proven to be good enough to recover the asteroids," said Amy Mainzer, who was NEOWISE's lead investigator at NASA's Jet Propulsion Laboratory in California, at the time. Lunar and planetary scientific conference in the woodlands, Texas. "Because he's never been designed for this purpose, he's nearing the end of his life."
Mr. Zurbuchen said today that the NEOWISE mission is expected to be completed by the middle of 2020, although he pointed out that the timeline is an estimate and that the validity period of the NEOWISE mission is about instrument could last longer.
Mainzer and his colleagues spent eight years thinking about how to take what worked for NEOWISE and design a new mission dedicated exclusively to monitoring asteroids. It means continuing to see the sky by thermal infrared, which is the heat that asteroids, fed by the rays of the sun, emit. Such a technique allows scientists to spot dark and reflective asteroids, which is an improvement over approaches that use visible light and therefore find it difficult to spot dark asteroids.
"There is a famous saying:" Why are we stealing banks? Well, that 's where the money is, "said Mainzer in March." In this case, we are looking for asteroids in these wavelengths because it is there that is the energy. "
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But there are some key changes in the design of NEOCam. It enjoys many years of camera and electronics development, and can scan the sky much faster than NEOWISE.
Most importantly, the device will be stationed at "parking spot"Balanced between the attraction of the Earth and that of the sun.This place is much colder than the outpost of NEOWISE, which means that NEOCam does not need cryogenic fluid. (When NEOWISE went into its coolant, the instrument lost the ability to measure a few key wavelengths.)
"It will sit in the cold darkness of space," Mainzer told NEOCam. The main mission of this project being designed to last five years, the team thinks that it could plausibly be twice as long. Today 's comments from Zurbuchen do not allow to know exactly how much NASA' s new mission will follow the specifications set by the NEOCam team.
Zurbuchen confirmed that the main mission of the new project would last five years and could be extended to ten years. This long life is essential: in 1998, Congress charged NASA with the identification of 90% of near Earth asteroids measuring at least 140 meters by 2020, but the government has not offered much money to help achieve this goal. According to current estimates of the number of asteroids around the Earth, scientists believe they have spotted about 30% of objects of this size.
The recently announced instrument will greatly increase this number, especially at the beginning of the mission, as the telescope flexes its improved muscle. According to Zurbuchen, the instrument will be able to recover 65% of undisclosed objects within five years, and it should be able to locate 90% of it within 10 years if the mission is extended.
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These detections would be a crucial addition to planetary defense efforts, which Zurbuchen noted NASA Director Jim Bridenstine judge important intersections between science and societal value. "This is a subject in which space reminds us from time to time that, indeed, on a historical time scale, global defense is something we need to look at regularly," said Zurbuchen.
The new budget format and NASA's decision to build a new space telescope to support global defense has been good news for the scientists who have looked into the issue. "NASA's commitment to a survey of asteroids in space is a huge step forward for anyone concerned about human destiny," said Richard Binzel, scientist in planetary sciences at MIT, at Space .com. "We will finally rely on knowledge, rather than luck, because our management plan dangerous asteroids. "
NASA staff present at today's meeting confirmed that prioritization was a long-overdue decision. "I think it's a big step forward, it's something we want to do for a long time," said Lori Glaze, director of the planetary sciences division at the science mission's directorate. "It looks like we are finally able to say we are ready to go ahead."
Zurbuchen reiterated this feeling. "The initiative for which I spent the most my balls is this one," he said.
And he is delighted to finally be able to launch the project. "Let's go do this mission," said Zurbuchen.
Email Meghan Bartels at [email protected] or follow her. @meghanbartels. Follow us on twitter @Spacedotcom and on Facebook. As long as you are there, you can get 5 issues of our partner "All About Space" Magazine for $ 5 for the latest amazing news from the last frontier.
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