Steve Gribben is a NASA/JohnsHopkins APL employee.
Humans have had nightmares about comets and asteroids hitting the Earth. The mass extinction 66 million years ago that killed off most of the dinosaurs is thought to have been caused by an object from space. It's true that a similar impact could end civilization.
The Double Asteroid Redirection Test is set to launch in November and NASA hopes to stop it. The plan is to crash into the smaller asteroid in the fall of 2022, trying to get it to move. That little nudging could make an asteroid miss Earth completely.
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NASA/JohnsHopkins APL/ Ed Whitman
DART was assembled and tested at the Applied Physics Laboratory. It will cost NASA $330 million for a probe that's leaving Earth.
DART is powered by the sun and will be testing NASA's NEXT-C ion drive in addition to using its 12 small thrusters. DART has one camera that will provide data to the system of algorithms that help the craft to steer itself autonomously. DART will be helped by DRACO to find a target that is the size of a building.
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The image is from NASA/Don Davis.
Planetary defense is the science of keeping asteroids out of the atmosphere. NASA is concerned about planetary defense, which may sound like science fiction. There are bits of space material on Earth. Most burn up in the upper atmosphere. Larger objects can make it closer to the surface.
A large house-sized meteorite exploded in the air above the Russian city of Chelyabinsk in January of 2013). The explosion was more powerful than a nuclear bomb and it injured over 1,000 people, mostly due to shattered glass. There are many undiscovered objects in our solar neighborhood that could cause a lot of damage.
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The image is from NASA/JPL-Caltech.
Most of the solar system's asteroids are in the asteroid belt, which is between Mars and Jupiter. The space rocks are pushed out of the belt by Jupiter's massive gravity, and are able to travel much closer to the sun.
Astronomers call them asteroids. They are appealing to scientists because of their close approaches to Earth. NASA's OSIRIS-REx spaceship visited one near-Earth asteroid, Bennu, to collect a sample of its surface and return it to Earth with delivery scheduled for 2023.
Near-Earth asteroids could pose a threat. There are an estimated 25,000 near-Earth asteroids larger than 500 feet in size, which have yet to be discovered. It would be enough to ruin a large city.
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The image is from NASA/Bill Ingalls.
DART will launch from a Space Force Base on the California coast.
Since the beginning of the Space Age, Vandenberg has been an important launch site. Satellites are usually launched around the Earth's poles, rather than the equator. The space shuttle was supposed to launch from Vandenberg, but that never came to fruition.
The mission faces a series of 84 different instantaneous launch opportunities.
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The image is from the Arecibo Observatory.
Dimorphos is an asteroid that is a little larger than the Great Pyramid of Giza. It's curious that it's in close proximity of a second asteroid, Didymos, which is about the size of a very tall skyscraper. There are two asteroids that are 0.75 miles apart. DART will be aiming for a system that is small. DART and its fellow missions will get the chance to study the two asteroids up close and personal.
Dimorphos and Didymos are not far from our part of the solar system. The two asteroids circle the sun in a highly elliptical way, taking them from beyond Mars to near the Earth's equator every 2.11 Earth years. When the asteroids are closest to Earth, DART will hit in 2022. The two asteroids pose no threat to Earth, so DART's test is just that.
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The image is from NASA/JHU-APL.
In the coming months, there will be other probes bound for Dimorphos and Didymos. A cubesat, a small satellite that's roughly the size of a shoebox and light enough that you could pick it up, will be on the main spaceship. The Italian Space Agency brought this companion to DART. DART's mission will be helped by the Light Italian Cubesat.
LICIACube will wake up before impact. Once free, it will adjust its own path, and it flies past Dimorphos three minutes after DART's crash. With two cameras on board, LICIACube will be able to autonomously track the larger spacecraft and let Earth see both DART's impact and its aftermath.
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The image is from the NASA/JohnsHopkins Applied Physics Lab.
When DART reaches Dimorphos, it will plunge into the asteroid at a gentle 15,000 mph. It takes 15 minutes from New York to Paris. DART will make a mark at that speed.
DART is a finely calculated and finely engineered operation, according to NASA. Everything from the asteroid to the angle and speed of impact has to be plotted out to get what mission leaders want. The asteroid could be destroyed by going too fast.
Scientists have been doing simulations for a long time in preparation for the big day. Depending on what day DART launches, that date will happen in late September or early October of 2022.
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The image is from NASA/JohnsHopkins APL.
How will scientists know if DART did its job? LICIACube will be right there, watching DART's crash landing and sending the results back to Earth. LICIACube will watch the crater and the dust left behind after the collision.
Astronomers will also be watching. When DART strikes the asteroid, it will be close enough that telescopes can see Dimorphos making circuits around Didymos. Scientists on Earth will be able to observe any changes to the space program after impact.
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The image is from the science office.
DART will not be the end of the story. The European Space Agency will launch a follow-up mission called Hera in 2024 and arrive at Didymos in 2026. Hera will look at Didymos four or so years after DART's impact and see what it looks like. Both missions are part of a larger, international program.
Hera will include more cubesats. Milani will study the dust around the asteroid. Juventas will attempt to land on Dimorphos to study what's inside the asteroid.
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