Africa-Press – Eritrea. Most mission scientists would wince at the thought of their spacecraft being smashed to smithereens.
But for those behind Nasa’s Dart probe, anything short of total destruction will be chalked up as a failure.
The $330 million spacecraft is due to slam head-on into an asteroid about 11m kilometres above the Indian Ocean soon after midnight on Monday.
The impact, at nearly seven kilometres a second, will obliterate the half-tonne probe, all in the name of planetary defence.
Astronomers will use ground-based telescopes to observe the asteroids before and after Dart collides.
Among them, a new telescope installed at the Turkana Basin Institute in northern Kenya aims to capture the moment of impact and the dust cloud Dart kicks up.
Not that Dimorphos, the asteroid in question, poses any threat to humanity.
The Dart, or double asteroid redirection test, is an experiment, the first mission ever to assess whether asteroids can be deflected should one ever be found on a collision course with Earth.
A well-placed nudge could avert Armageddon, or so the thinking goes, and spare humans the same fate as the dinosaurs.
“It’s a very complicated game of cosmic billiards,” Prof Alan Fitzsimmons, an astronomer and member of the Nasa Dart investigation team at Queen’s University Belfast said.
“What we want to do is use as much energy [as we can] from Dart to move the asteroid.”
With telescopes constantly scanning the skies, scientists hope to have some notice if an asteroid were ever to present a major threat.
“If we are able to see far enough in advance and know that an asteroid might be a problem, pushing it out of the way will be much safer than the big Hollywood idea of blowing it up,” Catriona McDonald, a PhD student at Warwick University said.
The Dart mission launched from Vandenberg space force base in November last year.
On Monday night, mission controllers will hand control to Dart’s software and let the probe steer itself into oblivion.
The collision, at about 3:14 am on Tuesday, Kenyan time will be recorded by Dart’s camera and two more onboard a small Italian probe called LiciaCube, which Dart released last week to witness the spectacle from a safe distance.
The Dart mission has been planned so that it does not inadvertently knock Dimorphos onto a collision course with Earth.
The 160-metre-wide rock orbits a second, larger asteroid called Didymos. When Dart collides, the impact will do nothing more than raise a cloud of debris and slow Dimorphos down, adding a few minutes to its orbit around the larger body.
“There’s no danger in this whatsoever,” Prof Colin Snodgrass, an astronomer and member of the Dart mission science team at Edinburgh University said.
“We are only changing its orbit around the bigger asteroid, we’re not changing its orbit around the sun. It cannot come towards Earth.”
The amount of debris will depend on the energy of the impact, the type of rock Dimorphos is made from and whether the material is loosely or tightly bound.
“The primary mission is a test of planetary defence, but at the same time, we can learn a lot about the asteroid,” Snodgrass said.
In the aftermath of the collision, scientists will work out how much Dimorphos has been slowed down by the impact. To do this, they will monitor the brightness of the larger asteroid, Didymos, which dims slightly every time Dimorphos crosses in front to complete a lap.
Dimorphos currently takes about 12 hours to orbit Didymos, and it is expected to take a few minutes longer once Dart has struck.
Astronomers track about 30,000 asteroids and comets that pass close to Earth’s orbit.
None of the big ones – those comparable in size to the 7-mile-wide asteroid that helped wipe out the dinosaurs 66 million years ago – are going to hit Earth in the next couple of hundred years.
But smaller ones are harder to spot and can still cause considerable damage. The meteor that exploded over Chelyabinsk in Russia in 2013 was less than 20 metres wide but created a shock wave that injured 1,600 people, mostly from flying glass and falling walls.
(Edited by Tabnacha O)
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