Nasa successfully crashes spacecraft into asteroid in ‘planetary defense test’ – live

Nasa chief: Planetary defense ‘a global endeavor’

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.

Nasa: ‘New era’ for humankind

Dart spacecraft collides with asteroid in successful ‘planetary defense test’

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.

“Precision lock” and final poll give Dart a green light

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.

Dart’s smart navigator locks on to Dimorphos

Nasa ‘optimistic’ of Dart mission success

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.

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:

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.

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 LiciaCube (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.

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.

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: