Did the historic NASA DART crash change the orbit of asteroid Dimorphos?

Just a few hours ago, the historic NASA DART mission came to an exciting and successful conclusion as the designated spacecraft, moving at the speed of 22,500 kilometers per hour, smashed into the asteroid Dimorphos. The mission was being conducted to test the planetary defense capabilities of NASA. While the asteroid itself was not a threat to the Earth, the test mission is supposed to help the space agency in collecting data in real-world conditions to see by what margin can the orbit of an asteroid be shifted if a high-velocity spacecraft crashes into it. But this data may not be fully available in the next few days. So, when can we realistically expect to know whether the spacecraft was able to change the asteroid’s orbit or not? Read on to find out.

Dimorphous is a 160-meters wide asteroid which orbits around a larger (780-meters wide) asteroid called Didymos. One of the reasons why this asteroid was selected was due to its smaller and observable orbit which makes it easy to assess and see the changes that can be caused by the spacecraft. It is expected that the spacecraft impact will push Dimorphos towards Didymos, both changing its orbit and increasing its orbital time. But it will be a while before we can truly observe this change.

“It’s like if you damaged your wristwatch and it started running a little bit fast. You might not notice it in the first day or two, but after a few weeks, you will begin to notice that it’s just not keeping the correct time anymore,” Tom Statler, the DART program scientist at NASA’s Planetary Defense Coordination Office explained in a news conference, reported Space.com.

When will we be able to see the impact of the NASA DART mission

The reason for the time taken is obvious. Only after the asteroid has moved considerably in its trajectory, will it be possible to determine whether its path has changed. And the observation is crucial. That is because NASA only has a very rough idea about the change that might cause. Rest will depend on the properties of Dimorphos. For example, if the asteroid is a solid block of rock, it will see a great impact but if it is made of loosely packed pebbles and dirt, then some of the impact might be absorbed by the asteroid. NASA has said that if the impact can increase the orbital time of Dimorphos by 73 seconds, it will be considered a successful mission. However, it is believed that the spacecraft might have taken close to 10 minutes off its orbital time.

“The telescopes will be watching the timing of the eclipses, when Dimorphos goes in front of Didymos, as we see it from Earth. Within a few days or weeks, we would see that those start happening off-schedule. I personally would be surprised if a month went by and we did not have a clear detection of that change. But we can’t say exactly,” said Statler.

So, it appears that it might take us close to a month to truly understand the extent of the spacecraft’s impact. If successful, it will no doubt become one of the most powerful tools to protect ourselves from dangerous space rocks.