[ad_1]
The Arecibo observatory is huge the radio telescope collapsed; with it it has become a crucial tool for understanding asteroid risks to Earth – and it would take serious government action to replace it.
Before the facility suffered irreversible damage in a string of cable failures this year, Arecibo Observatory it was the most powerful planetary radar system on Earth. Astronomers cannot use radar to discover new asteroids, but the data provided by these systems can provide scientists with the details about the size, shape and position of an object they need to better and more quickly assess the threat facing them. individual asteroids could account for the Earth.
“This is a difficult thing to bear [down] an iconic structure like this that is provided so much for radio astronomy and planetary radar community in so many decades; it’s really sad to see, “Lindley Johnson, who heads NASA’s planetary defense coordination office, said during a virtual meeting of NASA’s Planetary Advisory Committee held on November 30, the day before the facility collapsed.” It’s certainly not an ideal situation, but I think it’s really time to start investing in a new planetary radar capability. “
Related: Losing the giant Arecibo plate makes humans more vulnerable to space rocks, scientists say
But that’s easier said than done. There are two key complications at play when it comes to investing in planetary radar capability.
One is bureaucratic: planetary radar must be run from the earth’s surface. And while NASA leads the country’s asteroid-centric work, the US National Science Foundation (NSF) is leading the federal government’s ground observations, as does the Arecibo Observatory; NASA simply paid for the observation time on the radar system. With the sole exception of NASA’s infrared telescope facility in Hawaii, all of the agency’s observation facilities are in space.
(This is also complicated. Technically, the other planetary radar facility in the world, a Gold stone in California, it is operated by NASA, but this is because its primary job is to communicate with spacecraft crossing the solar system. The radar rig recently completed an update and has returned to normal observations, although it has a less flexible schedule than Arecibo’s and cannot see objects that far from Earth.)
Related: Losing the Arecibo Observatory would create a hole that can’t be filled, scientists say
“The way our agencies are tasked, ground observations are the responsibility of the NSF,” Lori Glaze, who heads NASA’s Planetary Science Division, said at the same meeting. “It’s not NASA’s purview.”
A second complication is the cost. A powerful radar beam like Arecibo’s requires both a powerful transmitter and a huge radio dish, neither of which is cheap.
Taken together, the challenges mean that NASA would likely need to work out deals with one or more government counterparts before a new planetary radar system comes online.
“This kind of thing really requires an agency partnership,” Johnson said, adding that Arecibo itself has traced its roots to a partnership led by the Department of Defense. Something like this could speed up planetary radar, he said. “We definitely have an opportunity and an interest in partnering with US Space Force on a more capable radar system. “The military branch is interested in technology as a way to track satellites between the Earth and the moon, he added.
Related: Arecibo is not the first radio telescope to fail unexpectedly. Here’s what we can learn from the collapse of the Green Bank.
A reduction in planetary radar does not hit the heart of NASA’s planetary defense system, which focuses on the discovery and monitoring of relatively large asteroids that are approaching relative to Earth. The detection of such objects relies on structures that detect optical and infrared light and scan large swaths of the sky regularly enough to notice when a new fast moving point appears against the background of the stars.
Radar can’t do that; it requires scientists to have a good idea of where exactly the object they want to study is, so that they can point the narrow radar beam precisely enough to bounce off the object. Instead, planetary defense experts use radar to more quickly track the orbit of an object farther into the future and to determine features of the object such as its shape and density that could influence attempts to deflect an asteroid if it appears to be on track to impact Earth.
“Regarding planetary defense and NEO [near-Earth object] observations are concerned, it is only a slight negative impact, “Johnson said of the loss of the Arecibo radar system.” It doesn’t affect our rate of discovery of near-Earth objects at all, it only has some impact on the opportunities we have to characterize these objects. “
Still, radar data is nice to have – and certainly the kind of thing Johnson would want for the planetary defense community.
Green Bank Observatory in West Virginia it was already planning to add radar capability to its primary radio antenna prior to the loss of Arecibo, scientists say, although the system, like Goldstone’s, will not replicate Arecibo’s specific abilities. And even that new capability would build on an existing structure, rather than starting from scratch, which comes with benefits and risks.
“In a perfect world, I would like to pursue a new planetary radar capability,” Johnson said, even before the final collapse of Arecibo. “Trying to keep these old structures running – they require a lot of maintenance.”
But a new capacity wouldn’t mean a copy of Arecibo’s iconic dish, he pointed out. “It’s really time to look at the next generation of planetary radar capabilities,” he said, specifically speculating that a set of antennas might be a more attractive approach now than Arecibo’s single plate.
“The technology has been going on since 30 to 40 years ago radar capability was installed at Arecibo,” Johnson said. “We have to take advantage of it.”
Email Meghan Bartels at [email protected] or follow her on Twitter @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook.
Source link
