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Last July, a unique event occurred. Not the right kind; the almost-almost-asteroid type of soccer field size. And this near-collision is the catalyst for a new NASA effort to detect more dangerous space rocks that could threaten the Earth.
The near-miss asteroid of last summer was named 2019 OK, and it passed about 77 000 km from the Earth. He managed to override all our detection methods and within 0.19 lunar distance from the Earth. In astronomical terms, it's remarkably close.
We only had 24 hours of notice that the asteroid would arrive, thanks to a small telescope in Brazil that spotted it. This near miss has sparked a renewed conversation about global defense and NASA's role in this regard.
It has also left people wondering how this could happen.
"I wonder how often this situation has occurred without the asteroid being discovered."
Paul Chodas of NASA's Jet Propulsion Laboratory, in an email.
Most of our asteroid detection telescopes are located on Earth, where weather and atmospheric conditions can limit detections. They also depend mainly on visible light. By 2019, OK was about to reach its near-accident with Earth. The brightness of the moon made it difficult to see. This, combined with the bad weather and low speed of the object, meant that we simply had not seen it.
WISE was reactivated in 2013 and named NeoWISE. NeoWISE used its infrared capabilities to identify asteroids in Earth's orbit. It was a success and discovered about 34,000 new asteroids, including 135 Near Earth Objects (NEO). NeoWISE still works.
But even NeoWISE missed 2019, prompting people to tackle the problem. The solution is twofold:
- We need a space system to find asteroids.
- We need a system that detects infrared.
In NASA emails published due to a request for access to Buzzfeed information, you can see the frustration felt by NASA about 2019, OK and all the problems who surround it.
In an email, Paul Chodas of NASA's Jet Propulsion Laboratory wrote: "This object has slipped through a whole series of our capture nets. I wonder how often this situation has occurred without the asteroid being discovered. "
Enter NEOCam
NEOCam (near-Earth object camera) has been under construction since the Congress set itself the goal in 2005 of detecting 140-meter asteroids. But he continues to bog down in the bureaucracy. As it is a global defense mission and not a scientific mission, it is increasingly ignored by NASA's other Discovery missions.
It has been stuck in the design and technology phase for years. He was never killed, he sat there for a while, while the promoters pleaded for its completion and launch.
In June 2019, National Academies of Science, Engineering and Medicine issued a statement acknowledging the problem:Recommendation: Missions meeting high priority global defense objectives should not be required to compete with missions that meet high priority scientific objectives.It may have been a defining moment.
Now, it seems that NEOCam could finally go from the front, and we could have the asteroid 2019 OK to thank him. Nothing motivates as much as fear.
On September 23, NASA embarked on a new asteroid-hunting space craft. Although they have not signed up specifically for NEOCam, many have advocated for this system and its design is already established. It could be ready by 2025 if it receives the necessary funding: between $ 500 and $ 600 million.
A presentation by Thomas Zurbuchen, Associate Administrator, Scientific Mission Directorate, provides some details.
NASA is calling this new spaceship asteroids "Neo Surveillance Mission". He sits in a Sun-Earth orbit L1. From this point of view, it will be freed from blind spots and gaps in a ground system. Using a 50 cm infrared sensor, he would find 65% of undiscovered PLHA> 140 m in 5 years (target: 90% in 10 years).
A system that detects infrared will be more effective than a visible light system because some asteroids are too dark to be detected in visible light. But they all emit infrared because of the energy that they receive from the sun. Generally, a sensitive infrared telescope must be cooled by cryogenics to work, but at point 1 of LaGrange, it is sufficiently cold without cooling. All he will need is a sunshade, much like the James Webb Space Telescope will use it.
If funding is in place and NASA commits to it, NEOCam could be operational for too long. He reports to the Planetary Defense Coordination Office (PDCO), which also works on the Double Asteroid Redirection Test (DART) mission. But DART eats the PDCO budget. DART will be launched in 2021 and its mission will cost $ 313 million. If Congress does not find a lot of new money, NEOCam will have to wait afterwards.
After all the quarrels and administrative and bureaucratic maneuvers, NEOCam, or a mission very similar to it, can finally come out of its extended design phase. It's better because asteroid impacts are a serious threat.
Remember the Chelyabinsk meteor? It exploded over Chelyabinsk Russia in 2013, causing extensive damage and injury. He slipped by undetected. And if she had been bigger? And if 2019 OK had taken a slightly different course?
"This one is sneaking on us …"
Lindley Johnson, NASA Global Defense Officer, in an email.
"This one apprehended us and it's an interesting story about the limitations of our current survey network," said Lindley Johnson, NASA's global defense officer in an email on July 26th.
In a press release issued several weeks after OK's overflight, he said: "If 201 OK had entered the earth's atmosphere above the Earth, the shockwave could have created a devastation located in a region of about 80 km ".
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