Exactly 7 Years From Today A Massive Asteroid Will Get Closer To Earth Than Some Of Our Satellites. Should NASA Visit It?

Exactly seven years from today—on April 13, 2029—the “Potentially Hazardous Asteroid” (PHA) called Apophis will pass inside the orbits of our geosynchronous satellites.

That’s about 23,000 miles/37,000 kilometers from Earth’s surface.

That’s close.

Apophis is enormous. Discovered in 2005, it’s reckoned to be about 1,100 feet/340 meters in diameter. That’s about as tall as the Empire State Building in Manhattan, New York.

It’s reckoned that an asteroid as big as that coming as close to Earth as Apophis will is a one-in-a-thousand-years event.

We are safe … for now.

Apophis isn’t going to strike our planet on April 13, 2029, but scientists think that the effect on it of the close pass could be to alter its trajectory—and dangerously so. It’s possible that Earth swing-by could put it on an Earth-resonant impact trajectory that come 2060 or 2068.

NASA doubts that, but given that Apophis just might cause a catastrophe in 40 years should we use the 2029 close shave to find out more about it?

That’s the theory behind the Apophis 2029 Planetary Defense Mission (PDM), a concept published last year and which is currently being considered as part of the Decadal Survey for Planetary Science and Astrobiology, a report compiled by the National Academy of Sciences that will set out the priorities for NASA for the next 10 years. It will be published on April 19, 2022.

The close pass in 2029 of Apophis is a rare opportunity to visit it, say the authors, who propose NASA launch a spacecraft to make vital measurements in the name of planetary defense.

“To be able to observe the changes that may be induced by the close approach to Earth, the Apophis 2029 PDM must rendezvous with Apophis some months in advance of the close approach,” reads the paper. It would remain at Apophis for several months afterwards.

Any spacecraft would need to launch in late 2027 and arrive at Apophis in late 2028, says the paper.

The main mission objectives for Apophis 2029 PDM would be to:

  • make impact risk assessments.
  • determine its physical properties.
  • determine its interior structure.
  • map its entire surface before and after the Earth flyby.

After all, if there’s even a small chance that Apophis could be nudged into a new trajectory that sees it collide with Earth in 2068 then we’d better now what it’s made of—and exactly how best to deflect or disrupt it on to a new trajectory.

It’s also an unmissable opportunity for astronomers and planetary scientists to get a close-up view of true relic of the Solar System’s formation.

Either way, the Apophis 2029 PDM would be an intriguing follow-up mission to the Double Asteroid Redirection Test (DART), the first-ever planetary defense mission from NASA and the European Space Agency (ESA). It smash a 500kg spacecraft into binary asteroid 65803 Didymos and its moonlet Dimorphos (also called, rather cutely, “Didymoon.”

DART launched in November 2021 and will arrive at Didymos and Dimorphos this September and during October will crash into Dimorphos at about 15,000 miles per hour.

The plan is to change its orbital velocity by 0.4 mm/s, which will in turn slightly alter the trajectory of Didymos—not because it’s dangerous to Earth, but because it could be a skill that NASA has to use one day to nudge a huge PHA … like, possibly, Apophis.

Wishing you clear skies and wide eyes.


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