NASAs many science missions now include learning how to deflect killer asteroids

But don't forget about the robots. They are having a landmark year, too.

Late Tuesday night, NASA is poised to embark on another groundbreaking mission - this one designed to eventually save Earth from a killer asteroid by testing whether a spacecraft can nudge a celestial body in a way that will alter its orbit. It's just the latest in a series of missions that this year have included a rover looking for signs of life on Mars, a small helicopter that continues to fly through the Red Planet's skies, and the possible launch of the most powerful telescope ever to go to space, capable of looking back in time to the early days of the universe.

Tuesday's launch at 10:21 p.m. Pacific time - 1:21 a.m. Wednesday on the East Coast - is set to see a SpaceX Falcon 9 rocket lift off from Vandenberg Space Force base in California. On its tip it will carry a refrigerator-sized spacecraft that will fly 6.7 million miles, hunting a small asteroid about the size of a football stadium before going kamikaze and crashing into it at 15,000 mph, likely next September.

If everything goes as planned, the impact will slow the asteroid by a fraction of a millimeter per second. That, scientists hope, will be enough that over time, in the vastness of space, it will alter the asteroid's trajectory significantly.

Dimorphos, the asteroid in NASA's sights, poses no danger to Earth. But it was chosen as the target for the so-called DART mission (that stands for Double Asteroid Redirection Test) by members of an elite NASA team known as the Planetary Defense Coordination Office - whose task isn't exploring space but defending Earth.

It is a "first test of planetary defense," Thomas Zurbuchen, the associate administrator of NASA's science mission directorate, told reporters Monday. "What we're trying to learn is how to deflect a threat that would come in."

There are lots of rocks hurtling through space large enough to survive the fiery plunge through Earth's atmosphere. NASA does its best to track them, but estimates it only knows of about 40% of the asteroids that could pose a danger. It's working on adding more space rocks to its catalogue, and in the meantime, trying to figure out how to make sure none hit Earth.

Unlike other natural disasters, such as hurricanes or earthquakes, humans could, NASA says, do something about killer asteroids.

In an interview, NASA administrator Bill Nelson said that an asteroid impact could have enormous consequences, even threaten humans' ability to live on earth. "We know a six-mile wide asteroid hitting what is today the Yucatán Peninsula was what wiped out much of life on earth, including the dinosaurs," he said.

The redirect mission follows another program that last year reached another near-Earth asteroid. After studying the Bennu asteroid for about two years, a spacecraft grabbed a sample from the surface with a robotic arm and is now on its way back to Earth. It would be the first time NASA has ever grabbed a sample from an asteroid, which could shed light on how the universe was formed.

This week, NASA also celebrated the 16th flight of Ingenuity, the four-pound helicopter that flew the first powered flight of an aircraft on another planet earlier this year in what NASA said was a "Wright brothers moment." Though it was only supposed to fly a handful of times, the sprite of a chopper has kept going, to the delight of NASA engineers.

Nelson said he was "very pleasantly surprised" and proud of "this little helicopter that we didn't even know would fly in an atmosphere that is 1 % of Earth's atmosphere. And now it's not only a demonstration, it's a scout."

Those events came in a year when NASA's astronauts were launching with regularity from United States soil for the first time since the space shuttle was retired in 2011. They were joined by a series of suborbital tourism flights from Richard Branson's Virgin Galactic, and Jeff Bezos' Blue Origin, which announced Tuesday that it would add Michael Strahan, the TV personality, to the ranks of its space passengers in December. (Bezos owns The Washington Post.)

"I'm super excited about all the successes on the human spaceflight side," Zurbuchen said. "We at science are huge champions for that and we sit there glued to the TV, just the same way as everybody else." But he said that "this has been a year of science, though, in an amazing fashion."

He noted that NASA landed its Mars Perseverance rover on Mars, and it is gearing up not only to return astronauts to the lunar surface, but first send a series of robotic spacecraft there. By the end of 2023 it intends to send the first mobile robotic mission there to analyze ice at the lunar south pole to help NASA create maps of the resource.

It is also scheduled to launch the James Webb Space Telescope, which would be stationed about 1 million miles from Earth and "explore every phase of cosmos history - from within our solar system, to the most distant observable galaxies in the early universe, and everything in between," NASA says.

After years of delays, the telescope was set to launch on an Ariane 5 rocket from French Guiana on Dec. 18. But NASA has delayed that flight until at least Dec. 22 after "a sudden, unplanned release of a clamp band" that was securing the telescope to its spot inside the nose cone of the rocket. NASA is now investigating to make sure "the incident did not damage any components," the space agency said in a statement.

Zurbuchen said they were taking every precaution to ensure the $10 billion telescope is safe before launching, and he said he hoped that "in a few days we'll be in good shape."