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After climate change, the next 100-year threat is asteroids. But NASA has a plan: a mission called DART. DW met with Thomas Zurbuchen of the Space Agency.

If an asteroid threatens the Earth, NASA’s DART spacecraft will test the technology to deflect the asteroid

DW: There are asteroids of different sizes, structures and materials-some are essentially metal balls, while others are "gravel pits". But let's focus on size first: the Double Asteroid Redirection Test (DART) mission is heading to a pair of asteroid Didymos and its moon Didymoon. They are called binary near-Earth asteroids. Didymos has a diameter of approximately 780 meters (2,559 feet), while Didymoon has a diameter of 160 meters. But you think that asteroids like Didymoon pose a greater threat to life on Earth. why is that?

Thomas Zurbuchen: Yes, that's right. Smaller asteroids pose a much greater threat to the Earth. If you look at the "crater history" of the moon or the "crater history" of our own environment, you will understand this. We have experienced similar asteroid bombardments for millions of years, but you just can’t see it because we have such active geology on Earth.

We are aware of some [larger] events, such as the asteroid that wiped out the dinosaurs. That is 10 kilometers (6.2 miles) in size. That kind of asteroid will change the entire planet, or change the life on it, but we don’t know of any asteroid of this size today. If a 160-meter-high asteroid hits a city, it will be a bad day for the city, but it will not change the entire planet.

Now, we don’t know that any asteroid of this size will pose a threat in the next 100 years, but having said that, we have only observed one-third of them. 

Wait a minute, let's roll back a bit. If an asteroid lands on a city, "this is a bad day for the city." When an asteroid lands on a city, what are its bad days? 

It depends on the size of the crater. As I said, the asteroid that wiped out the dinosaurs was 10 kilometers wide, but the craters it left behind were 100 or 200 kilometers—10 times or more the size. Therefore, a 160-meter-high asteroid will leave more than one kilometer crater. If that asteroid hits a city, the crater it formed is basically the city it used to be.

So, what prevents us from discovering these asteroids? 

Well, we are working hard. There is an observatory around the earth, and you can see the sky at night. The two most productive telescopes are in Hawaii, and they will observe two to three new asteroids every night.

But we still need to go to space to reach 100%. We are starting a mission called NEO surveyor-or low-Earth orbit surveyor-at NASA, and this is its purpose. It will be launched in a few years.

But now, you are starting DART. Tell us this idea of ​​causing a "dynamic shock deflection" to Didymoon at a speed of 6.6 km/s. As far as I know, this will push the asteroid enough to change its orbit for a few minutes. Is this enough to prevent asteroids from hitting the earth?

Usually, it depends on some variables. First, it depends on how early we observe the asteroid before the impact. The sooner we observe it, the smaller the deflection-the less we need to get out of what we call "keyholes" or dangerous areas.

Secondly, it depends on the mass of the asteroid. We want to change its speed, and the mass ratio of asteroids and spacecraft is important for this. Third, the orbit of the asteroid is important-you want to make a frontal collision to use the energy of the asteroid. So, it all depends. But this is exactly why we tested this technology, because at this time all these variables are unknown.

What distance are we talking about, and how early is "early"?

Ideally, we want to know what asteroids will be many years later, the reason is simple, we need to launch missions and put them into orbit. Or we can have a space technology and be ready. Generally speaking, we can calculate the chance of an object hitting the earth on a time scale of 10, 20, or even 100 years. But if it is a few weeks or a month later, it will be difficult to use this technology.

Many of these objects are within the distance between the sun and the earth (Editor's Note-149,600,000 kilometers or 92,900,000 miles) or farther. It can be anywhere, from the orbit of Mars or beyond, all the way to Venus. It's the whole range.

How did Europeans get into it? They will start part of their mission in 2024, the HERA detector.

Therefore, DART will hit the asteroid, transmit power and form a crater. ESA's HERA probe will then investigate the crater and find out why our impact produces such a large momentum and crater.

The space agency’s mission has visited many asteroids and comets

Because there are different types of asteroids...

If the asteroid is a metal ball, you can use entry-level physics to understand momentum transfer—that is, mass multiplied by speed. But if it's a gravel pit, it's a different matter. Therefore, Europeans will help us in many basic sciences.

They are also working on a forward-looking project to park a technology in space so that it is readily available, which means we don’t have to launch an impactor from the earth.

How healthy is the support for planetary defense? What I mean is that we are facing climate change on a time scale of less than a few decades, not on the time scale of the centuries where asteroids exist. Do you have the support you need, or before we study how to save it from the asteroid, does anyone say "Let us see if we have a planet that can be saved in 100 years"?

At NASA, we believe that we should support research on different time scales. Consider these numbers: The proposed budget for Earth Science, which is at the center of the climate crisis, is US$2.5 billion (2.2 billion euros) per year. The current planetary defense budget is $150 million per year. But if there is a threat, we will increase the budget.

I have children. I will do my best to ensure that the planet remains healthy for 100 years. This is why we are committed to climate science, but at the same time, we want to look at the less imminent threats and build tools to have them when they arise.

Space is a common thing that all of us use, and we need to be able to rely on it. Europeans are our main partners in this area, but we can easily imagine collaborating with others. Global challenges require global cooperation.

Dr. Thomas Zurbuchen is the Deputy Administrator of NASA’s Science Mission Directorate.

Zulfikar Abbany conducted an interview.

Fly over? Nothing new. But fly over the same planet twice a day? That's very special. In August, two probes flew over Venus. This was the first space probe—BepiColombo flew to Mercury, and the solar orbiter flew to the sun. Without overflight and gravity assistance, they would not be able to achieve their goals. Sadly, the two men did not bite into each other. They are 575,000 kilometers (357,000 miles) apart!

BepiColombo took this cool picture of Venus. But shooting is secondary. The probe flew over Venus to help it slow down. It needs to match its "orbital energy" with Mercury's "orbital energy" to enter the planet's orbit. Bepi starts with the (larger) orbital energy of the earth and is trading off excess energy. Simply put, it gave it to Venus, and it was aided by gravity—a slingshot, the planet swings.

It started with the Cold War-the first space race. The Soviets first tried to fly over Venus in 1961, but failed. The United States did it with their Mariner 2 detector a year later, and it must be very hurtful. By the time the Soviet Union achieved its first success in 1978, the Americans had completed the exploration of Mercury, Mars, and Jupiter. But the Soviets were the first to go to the moon, which is a bigger problem.

Voyager 1 and 2 spacecraft were launched into space in 1977 and were sent to explore the outer solar system. Each of them carries a golden record of the voice of the earth: Our story is told for aliens. Flybys include Jupiter, where V1 captured the Great Red Spot (storms that raged for hundreds of years), Saturn, Uranus, and Neptune. They are now beyond our solar system in interstellar space, so they are the "farthest man-made objects".

People often talk about our lonely, cheesy moon with love and surprise. So why not? If we have 79 satellites like Jupiter, the situation is different. Voyager 2 discovered one of them (there are five on Neptune). It also discovered that Jupiter’s moon Europa may have some form of life outside the Earth. We are very interested in its Aral Sea. NASA hopes to learn more through its probe Europa Clipper.

If you think 79 satellites are cool, try 82. This is Saturn. The Cassini spacecraft is a joint mission of the United States and Europe to detect Saturn and its satellites. It made 162 targeted overflights of Saturn's moons, including Titan and Enceladus, where it discovered the ocean world. After 13 years of exploring the planetary system, Cassini dived into Saturn for the last time, and did not observe until the end.

Voyager 1 and 2 have a companion on the edge of our solar system: New Horizons. After orbiting Jupiter to increase gravity, it made a six-month flyby to study the dwarf planet Pluto. It then ventured to the Kuiper Belt, where it filmed Voyager One with a camera. Pioneer 10 and 11 are the only other detectors that have come this far. These missions help us answer questions about space geology and life.

There are many other notable flyby missions-Rosetta completed the Earth and Mars flybys before heading to Comet Curry, Giotto on Halley’s Comet, Deep Space 1, Deep Impact, Stardust, the first to return to the comet Sample return mission...and in the future: Hera, this will be the first human probe to rendezvous with Didymos, the double asteroid system. Why? It all depends on our identity and position in the universe.

The moon is just one of India's space ambitions. These range from telecommunications to telemedicine, from remote sensing to rockets, and planetary science. These are India’s seven extra-planetary targets.  

On Monday, the seven current passengers of the International Space Station had to enter the docked spacecraft twice, worrying about the possible impact of space debris.  

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