‘Basically a bullseye’: Nasa crashes spacecraft into asteroid to test Earth’s defenses – as it happened

The Guardian
The Guardian

2.07am BST

Closing summary

We’re closing our live blog of Nasa’s Dart “planetary defense test” now after what scientists have hailed a “game-changing” achievement in crashing a spacecraft into a faraway asteroid.

  • Nasa chief Bill Nelson said the mission would “teach us how one day to protect our own planet from an incoming asteroid. We are showing that planetary defense is a global endeavor and it is very possible to save our planet.”

  • Mission managers at Johns Hopkins University’s applied physics laboratory say it could be up to two months before telescope observations will show whether the impact had sufficient force to alter the trajectory of the asteroid Dimorphos , 6.8m miles from Earth.

  • But the first part of the mission was successful, Dart’s crash landing 17 meters from its intended target on the asteroid the width of a football stadium close enough to count as “basically a bullseye”, according to deputy program manager Elena Adams.

  • Ralph Semmel , director of the Johns Hopkins applied physics laboratory, hailed the “game-changing” nature of the mission, adding that his team knew they had been successful when the video blacked out. “Normally, losing signal from a spacecraft is a very bad thing. But in this case, it was the ideal outcome,” he said.

Thanks for joining us. You can read our news story about the Dart mission here:

Related: Nasa successfully crashes spacecraft into asteroid in planetary defense test

Updated at 2.17am BST

1.40am BST

Dart scientists: 'ideal outcome' for first planetary defense test

Scientists say it will be about two months before they know if the Dart spacecraft has altered the trajectory of the asteroid Dimorphos, but hailed the “ideal outcome” of the first stage of the planetary defense test.

Dart scored “basically a bullseye” on the asteroid about 6.8m miles from Earth when it crashed head-on at 7.14pm EDT, Dart deputy program manager Elena Adams said at a post-mission press conference:

We knew we were going to hit. All of us were holding our breath. I’m kind of surprised none of us passed out.

She said the craft had landed 17 meters from its target, which she said mission managers knew because “the asteroid was not completely lit from all the sides”. It was, she said, close enough to represent a complete success:

It was basically a bullseye. I think, as far as we can tell, the first planetary defense test was a success, and we can clap to that.

Whether the impact had enough force to move the asteroid from its trajectory remains to be seen. If it has, the second goal of the mission, to show humanity’s capability of diverting an Earth-bound large asteroid, will also have been achieved.

But scientists will spend at least two months monitoring the asteroid’s speed and movements, and making calculations.

Even so, Adams said:

Earthlings should sleep better, and I definitely will.

Other managers expressed their “absolute joy” at the successful collision.

Ralph Semmel , director of the Johns Hopkins applied physics laboratory, hailed the “game-changing” nature of what had just been achieved, adding that his team knew they had been successful when the video blacked out:

Normally, losing signal from a spacecraft is a very bad thing. But in this case, it was the ideal outcome.

Dart has now joined a long list of [Johns Hopkins’] applied physics laboratory’s firsts in space. The first photos of Earth from space, creation of satellite navigation with the transit system, the incredible New Horizons flyby of Pluto, and the record setting Parker Solar Probe that has touched the sun ...

We can now add to this this our world’s first planetary defense test mission. Congratulations to the Dart team and to Nasa on this historic accomplishment and first demonstration of a game changing planetary defense capability.

Updated at 1.44am BST

1.07am BST

The Dart mission press conference is under way:

12.59am BST

Nasa chief: Planetary defense 'a global endeavor'

Bill Nelson, a former astronaut who is now Nasa’s administrator, commended the Dart scientists, managers and workers, thanking the “international team” that worked on the project.

In a recorded statement broadcast after impact was confirmed, Nelson said:

Hey, congratulations. Boy, the Dart team … you really did this one very well.

It’s been a successful completion of the first part of the world’s first planetary defense test. And there were years of hard work. There was a lot of innovation and creativity that went into this mission.

And I believe it’s going to teach us how one day to protect our own planet from an incoming asteroid. I really look forward to learning all about what’s happening from the observatories, so they can tell us about the changes in this asteroid’s orbit.

So thank you to this international team. We are showing that planetary defense is a global endeavor and it is very possible to save our planet.

Updated at 1.06am BST

12.50am BST

The part of the Dart mission in which the spacecraft collided with an asteroid has been successfully concluded, but how will Nasa know if the impact has accomplished its twin goal of shifting the space rock from its trajectory?

The answer will come from Earth-bound telescopes monitoring the twin asteroids Dimorphos and Didymos , checking on their speed and movements.

Johns Hopkins’ planetary scientist Nancy Chabot explained:

This is a double asteroid system. So all we’ve done here actually is changed slightly how Dimorphos goes around Didymos. The telescopes on Earth have studied this for years.

We knew [one orbit] used to be 11 hours and 55 minutes. What is it going to be now? The telescopes are gonna measure that period of change, and they’re so good at this. They’ve done it for decades already to get us to that point, and they’re gonna work for the next weeks and make that measurement.

And when we have it, we’re going to be sure to share it with everybody to see how much we did deflect this asteroid with the Dart collision.

Updated at 12.56am BST

12.30am BST

Nasa: 'New era' for humankind

Nasa has embarked on a “new era of humankind” by sending a spacecraft hurtling into an asteroid almost 7m miles from Earth, its scientists say.

Lori Glaze , Nasa’s planetary science division director, made the statement shortly after confirmation that the agency’s Dart spacecraft had successfully impacted Dimorphos on its first “planetary defense mission”:

We’re embarking on a new era of humankind, an era in which we potentially have the capability to protect ourselves from something like a dangerous hazardous asteroid impact.

What an amazing thing. We’ve never had that capability before.

Teams of Nasa and Johns Hopkins University scientists hugged each other as Dart’s successful impact with Dimorphos was confirmed .

Samson Reony , Johns Hopkins’ mission commentator was equally as exuberant about the “game changing” achievement:

This is when science, engineering and a great purpose, planetary defense, come together, and, you know, it makes a magical moment like this.

Updated at 12.48am BST

12.16am BST

Dart spacecraft collides with asteroid in successful 'planetary defense test'

Nasa’s Dart spacecraft has crashed into the asteroid Dimorphos 6.8m miles from Earth in the space agency’s first “planetary defense test”.

Confirmation came shortly after its 7.14pm EDT collision at 15,000 mph.

It is humanity’s first attempt at moving another celestial body, the goal being to see if a large asteroid hurtling towards Earth could be diverted.

The lag from deep space provided video confirmation 38 seconds after impact, plus a few more seconds for image processing.

Updated at 12.23am BST

12.09am BST

Six minutes to impact on what is one of Nasa’s coolest missions of recent history.

It has taken Dart 10 months and 470m miles to get here, since launch last year.

“It’s a truly global effort,” Nasa’s livestream commentator says:

Usually Nasa spacecraft are intended to operate for many years, or even decades, but not Dart.

Dart was built to be destroyed. Dart is a mission of firsts, proving that a spacecraft can autonomously seek, find and approach a target in space that’s so far away we don’t even know what it looks like.

11.58pm BST

"Precision lock" and final poll give Dart a green light

A final poll by mission managers has given Dart the green light to crash into Dimorphos at 15,000mph (24,140km/h) in a little less than 20 minutes’ time.

The supervisors of ground systems, image quality, smart navigation, guidance, navigation and control (GNC) and deep space network (DSN), all gave a final go-ahead, reporting that all systems were working “nominally”, which in space terms means normal.

We’ve also just received confirmation of a “ precision lock ” by Dart on its target asteroids, Didymos and Dimorphos, an additional, final step to the earlier confirmed lock by the SmartNav navigation system.

Looks like it’s going to happen!

Updated at 11.59pm BST

11.45pm BST

Fictional movies such as Deep Impact to Armageddon and Don’t Look Up would have us believe that the best way to deal with an asteroid hurtling towards Earth is to obliterate it.

But scientists at Johns Hopkins University say that’s just what we shouldn’t do.

Andy Rivkin , of JPL’s ’s applied physics laboratory, and Dart investigation team lead, has just been explaining the reasoning behind it:

Conventional wisdom for planetary defense is that you don’t want to disrupt an object and blow it into a million pieces, but you want to keep it intact and just move it all as one piece.

Because if you move it all in one piece then you can keep track of it a lot easier. If you blow it into a million pieces, then some of them might still [collide with] Earth, and you don’t want to miss a thing.

The twin asteroids of Didymos and its moon Dimorphos , Rivkin says, were the perfect test subjects:

We needed something with a moon that was small enough that we could move it with a strike from a spacecraft, but not so small that we wrecked the moon.

So when you kind of tick off all the possibilities, Didymos ended up as the best choice, and really the only choice, that would provide a mission in this time period.

Updated at 12.33am BST

11.34pm BST

Dart's smart navigator locks on to Dimorphos

Dart’s SmartNav navigation system is now locked on to its target of Dimorphos, mission managers have just announced.

It’s another crucial step towards successful completion of the mission, and validation of the technology that was tested using Jupiter and its four moons .

Meanwhile, the little white dot in the center of the screen on the livestream of the mission is growing ever larger as Dart closes in on Dimorphos at four miles per second.

Everything appears still on track for impact at 7.14pm EST (12.14am BST).

“Now we wait for history,” JPL commentator Samson Reiny says.

11.19pm BST

Nasa 'optimistic' of Dart mission success

We’re a little less than one hour away from the collision of the Dart spacecraft with the asteroid Dimorphos, at 7.14pm E DT.

Mission managers have just conducted a status poll to ensure everything is on track. Everything appears to be progressing smoothly towards the moment of impact, and the spacecraft is behaving as expected.

A final poll will be taken 30 minutes from impact.

Dr Thomas Zurbuchen , associate administrator of Nasa’s science mission directorate, says the agency is “optimistic” that tonight’s mission will be successful:

I always think it’s the world is made out of a box. There are things we know that we can use and a large space of things that are unknown. In that large space are solutions for problems of the future.

There’s new research, new understanding of nature. And we at Nasa are all about moving that boundary back to make more things useful for us, like Dart, but also understanding nature in a new fashion.

This is a step in that direction. We’re very optimistic.

Updated at 12.23am BST

11.09pm BST

Not everyone at Nasa will be focused on tonight’s asteroid mission. As the full fury of Hurricane Ian closes in on Florida , mission managers of Artemis 1 , the space agency’s first crew-capable lunar mission in half a century, also have an eye on the sky.

Earlier today they made the decision to send the giant Space Launch System moon rocket back to the safety of Kennedy Space Center’s vehicle assembly building from its oceanfront launchpad.
Artemis 1 on the launchpad at Florida’s Kennedy Space Center. Photograph: Brynn Anderson/AP

It’s another frustration for the space agency, which has seen two launch attempts from Cape Canaveral thwarted in recent weeks because of technical issues.

The rocket’s 4.2 mile journey atop one of Nasa’s giant crawlers will take about 11 hours, and will further delay the next launch attempt into at least mid-October.

Bloomberg’s space reporter Loren Grush wonders if tonight’s Dart mission might prove somehow cathartic:

10.58pm BST

Here’s a few more details from Nasa about the target of tonight’s “planetary defense test”, the 525ft (160 metre) diameter Dimorphos.

It’s length is about the same of 1.5 football fields, and is the smaller of two asteroids in a double-asteroid system that the agency deems perfect for the mission. Dimorphos orbits the larger asteroid, Didymos (Greek for “twin”), every 11hr 55min.

According to this helpful account of the science behind the Dart mission from Nasa’s Jet Propulsion Laboratory:

Neither asteroid poses a threat to our planet, which is one reason why this asteroid system is the ideal place to test asteroid redirection techniques.

At the time of Dart’s impact, the asteroid pair will be 6.8m miles (11m km) away from Earth as they travel on their orbit around the Sun.

Regardless of how much or how little the orbit of Dimorphos is changed by Dart, the asteroid will not become a threat to Earth.

Which is certainly a huge relief.

Updated at 10.59pm BST

10.44pm BST

We’re (hopefully) going to be able to watch the Dart spacecraft’s collision with Dimorphos live, or at least on a few minutes’ delay, thanks to what Nasa calls the mission’s own “mini-photographer”, the L iciaCube (short for Light Italian CubeSat for Imaging Asteroids).

The satellite craft will fly past Dimorphos about three minutes after Dart crashes, Nasa says, aiming “to confirm the spacecraft impact, observe the evolution of the ejected plume, potentially capture images of the newly formed impact crater, and image the opposite hemisphere of Dimorphos that Dart will never see”.

The cameras have already been busy. Earlier this week, as part of the calibration process, LiciaCube captured images of a crescent Earth, and the Pleiades star cluster, also known as the Seven Sisters.

The image part of the project is managed by the Italian space agency’s robotic exploration mission office, while overall responsibility for managing Dart rests with Johns Hopkins University’s applied physics laboratory in Laurel, Maryland, for Nasa’s planetary defense coordination office.

You can read more about LICIACube here .

Updated at 12.25am BST

10.21pm BST

And here’s an explainer we published earlier about the Dart mission, which Nasa is running in association with scientists from Johns Hopkins university.

It’s important to point out that there is no current threat to Earth from an asteroid … this test mission is taking place to assess our readiness if such a peril ever materialized.

But it’s a subject that’s been in the public eye recently, notably through last year’s Netflix comedy Don’t Look Up , in which Earth faces impending doom from a menacing asteroid and barely anybody seems to care or notice.

Related: Why Nasa is crashing a spacecraft into an asteroid – and how to watch it

Updated at 10.44pm BST

10.11pm BST

Good afternoon blog readers, space enthusiasts, and those who just want to know if humanity can be saved from the apocalypse of a giant asteroid slamming into Earth.

In about two hours from now, at 7.14pm ET, Nasa will take the first steps towards finding out. The space agency will intentionally crash a spacecraft the size of a small car into Dimorphos, the moon of the asteroid Didymos, orbiting about 6.8m miles away.

The aim of the Dart (double asteroid redirection test) mission is to see if the asteroid’s trajectory can be altered by the force of the impact, thereby suggesting humankind has the capability of at least attempting to avert such an Armageddon-style event.

The unprecedented “planetary defense test” is a venture several years and $325m in the making, and is the first of what Nasa intends to be a series of missions to assess our readiness for the threat of a large asteroid impact.

We’ll bring you all the developments as they happen over the next few hours, but before we get started, let’s take a look at the mission itself:

Related: Nasa to crash spacecraft into asteroid in planetary defense test

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