Why Nasa is crashing a spacecraft into an asteroid – and how to watch it
An unprecedented and long-awaited deep-space venture will take place almost 7m miles from Earth on Monday night when a Nasa spacecraft will be deliberately crashed into an asteroid in an attempt to show humanity can avert an Armageddon-style impact to Earth. Here’s what’s happening, and why: What is the Nasa Dart mission?
The acronym stands for Double Asteroid Redirection Test, the first “planetary defense” experiment conducted by the US space agency, in association with scientists at Johns Hopkins University, to see if it can alter the trajectory of an asteroid in deep space if one ever comes close enough to threaten Earth.
What is Nasa planning to do?
The agency has targeted the nearEarth asteroid Didymos, more specifically its 525ft (160 metre) diameter moon Dimorphos, into which it will crash a small car-sized spacecraft at 7.14pm EST (12.14am BST, 9.14am AEST). The asteroid and its moon were chosen for their proximity of about 6.8m miles away, but neither pose a threat to our planet before or after the collision.
Why is the mission taking place? Anybody who has watched the recent Netflix comedy Don’t Look Up will be familiar with the threat, however remote, of an asteroid big enough to be world-ending hurtling towards, and one day colliding with Earth. Nasa wants to know if it has the capability to protect us if such a scenario ever occurs.
What does Nasa hope will happen? The plan is that the 15,000mph (24,140km/h) impact of the Dart spacecraft will be enough to nudge Dimorphos from its current trajectory and on to a different path. Children of the 1980s will recall the popular video game Asteroids in which the objective was to change the direction of menacing space rocks (and then destroy them, which is not the goal of Dart). There are also no lethal flying saucers.
How will we know if the mission is successful?
Nasa is livestreaming the mission with video and commentary on its website and social media channels. A press conference is also scheduled for about 45 minutes after the impact during which mission managers will discuss what happened. You can follow all the developments on the Guardian’s live blog starting at 5pm EST (10pm BST, 7am AEST).