Dimorphos is a space rock far from the earth and we don't even know what it looks like - on Monday, we will smash it with a spacecraft. The Double Asteroid Redirection Test (DART) will travel at 14,000 miles per hour when hitting the asteroid, which must be one of the most metallic scientific experiments ever.
DART is an effort by NASA to see if it can change the motion of asteroids in space. It is advertised as the world's first "planetary defense test mission" - a test run to see if we have the ability to avoid serious asteroid impacts on Earth sometime in the future. You know, just in case.
It is very clear that neither Dimopos nor his larger companion Didimos pose any threat to the earth. In fact, we have not found any asteroids that that poses a direct threat to our planet. These two are just good goal exercises. Diffimos and Didimos are a binary asteroid system, and Diomos is Didimos' "satellite". When the small satellite orbits a larger asteroid, it passes between the larger asteroid and the earth. This means that telescopes both inside and outside the real world can monitor the system and see relatively quickly the impact of the crash on the speed and trajectory of Dimorphos. Shortly after the impact of
, telescopes from various continents on Earth will focus on the system to see the consequences. Outside the world, James Webb Space Telescope, Hubble Telescope, and even the asteroid-bound Lucy spacecraft will train their eyes to the asteroid system, waiting for what will happen when a rock meets a hard spacecraft. The impact is expected to change the speed of Dimorphos by a fraction, which will change the time it takes to complete its orbit for several minutes. This doesn't seem to be much, but for planetary defense scientists, the time is huge. “This demonstration is very important for our future on Earth,” Lindley Johnson, NASA planetary defense officer, said in a pre-mission press conference.
This demonstration is extremely important for our future on Earth
Johnson said this moment in history is unique. This is the first time that humans understand both the threat posed by asteroids and truly have the technology to act on it. If we do find a huge rock rushing towards the earth, it's a good thing to have a plan on how to stop the rocks or two - it might be better to do some exercises under our belt.
"DART is showing what we call kinetic energy impact technology to change the velocity of asteroids in space and thus change their orbits," Johnson said. There are other options in the
Planetary Defense Toolbox, including the Gravity Tractor, a spacecraft that can fly next to an asteroid, gently pulling it onto a safer path. It is also possible to launch ion beam to the asteroid for a long time, pushing it to different orbits. DART first try a more straightforward approach; go forward at full speed.
prepare for the impact
During the final entry process, DART will drive automatically. The control room will have about 44 people watching the telemetry and data, but starting about four hours before the impact, “the spacecraft has to do everything,” Elena Adams, DART mission systems engineer at Johns Hopkins Applied Physics Laboratory, said in a news release. It has an intelligent navigation system on board that guides it into the Didimos/Dimopos system. It discovered Didimos earlier this summer, but it could not see the actual target Diimos until about an hour before the impact.
When it discovers Dimorphos, this 163-meter-wide (530 feet) asteroid will be displayed as only one pixel. This would be enough for the navigation system to start tracking the rock itself, rather than its companion asteroid. Adams said that the navigation system that brought the spacecraft to that point would be turned off two and a half minutes before the impact. “We’re just going to aim at the camera and take the most amazing pictures of this asteroid we’ll see for the first time.
Scientists don't have a $250 million spacecraft crash every day, as Adams told before DART launch last November. Because this is a once-in-a-lifetime experience, the team will record the collision in detail.
Scientists don't have a $250 million spacecraft crash every day
In addition to the observatory that will be viewed on space and on Earth, DART's own camera will also send back images until the last moment, sending them back to Earth so that people can watch the dramatic ending of the mission.
In addition, a small companion spacecraft will record operations in space. Italy's LICIACube (the Italian light cube satellite used to image asteroids) was launched with DART on September 11 and separated from the larger spacecraft. It is following its companions and will record the consequences of the experiment, flying by Dimorphos about three minutes after the impact. It will also have a chance to see the other side of Dimorphos, which larger spacecraft will never be seen. What will happen next in
?
"This mission is divided into two parts. The first part is impacting the asteroid, and the next part is actually what happens after the measurements," Adams said. The team expects the asteroid to run faster after a collision and will track it over time.
"It's like you've thrown your watch and damaged it. It doesn't necessarily keep the same amount of time," said Tom Statler, a project scientist at DART. “You may not notice it right away, but over the next few weeks, days and weeks, you will notice your watch running very fast – We will notice that the binary asteroid system runs very fast. Statler says.
It's like you've dropped your watch and damaged it
While Statler and other researchers have a good idea of what might happen to after the crash, a big reason for this test is that we don't know what happens when we hit an asteroid. Information on how asteroid reacts to impacts can help calibrate future tests and ultimately tell us how to approach threatening asteroids.
"As a scientist, I totally hope to be surprised by the experimental results," Statler says. "Although as a planetary guard, I don't want to be too surprised."
