The Didymos system made DART's deflection test easier to measure because Dimorphos completes a short orbit around a larger asteroid. Researchers could compare that moonlet's orbital period before and after impact, rather than wait to detect a tiny change along a much longer solar orbit. DART itself struck Dimorphos; the separate LICIACube spacecraft observed the impact and ejecta.
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Before the impact, Dimorphos completed an orbit around Didymos in roughly 11 hours and 55 minutes.
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18:27of this podcast released on Thursday, I'm giving a talk. So you know, if you're going, just look me up on the schedule and come check out my talk on Thursday. I'm still, you know, doing doing stuff and and talking to people about all the research that I'm doing. And if you want to know about the research that he's doing, which is very interesting, make sure if you're at APS, you go see it and embarrass Krishna by asking for an autograph in front of all the scientists and academics. >> Okay, let's get back to the story, please. >> All right. The target of the Dart mission was the Ditimus Dorphus binary system. Just to show how the two
19:08asteroids compare, the moon, the moonletit that we were trying to target is a bit bigger. It's in between the Statue of Liberty and the Eiffel Tower in terms of how big it is. Ditimus is like Bourj Khalifa type >> in terms of how big it is, like the diameter. >> Um, and what we're trying to kamicazi is the moonlight. Yes. The little the the little small one. Yep. >> Okay. So in during the mission actually the main dart like asteroid or sorry the main dart probe the satellite actually stood behind to watch this unfold and it let out a little like >> uh >> kamicazi satellite drone >> one go.
19:49>> Yeah, exactly. And and so this gu this guy's job was to go and bomb >> Yes. >> Dorphice. Let's say let's say make contact. >> Make contact. Sorry, I I shouldn't. Yeah, in today's world, let's let's rephrase that. We're trying to make contact with Dorphis and the other the the main ship, the mother ship is watching this all in action because it wants to see what is the effect. >> Yes. >> Of that contact on the system. Why binary? It's because we want rapid measurement of deflection, right? >> We want to the orbit is going one way. We want to see if it's slowed down or sped up. Okay? Whatever. And with a with a dual orbit system, it is easier to
20:31ascertain the answer to that than a single object moving. >> Yes. Exactly. And here's why. >> Okay. >> The mutual orbit velocity of Dorphis and Ditimus is about 17 cm/s. >> Okay. >> Okay. Which means that if we were to impact some momentum, 17 cm/s, even for something as large as, you know, a rock, a mountain, let's say, I can reasonably try and discern some change because I'm going at it at 6 km/s. So reasonably, some of my momentum is going to get transferred and then I'm going to be able to see a change. And they were able to see a change. They saw that the mutual orbit period of was altered by 33
21:13m. And this is something that we can rapidly measure. The orbit got smaller. It got shorter by 33 m. And the dart system, which is monitoring this, >> can calculate that, measure it, no problem. M >> make makes total sense. We set up an observer and uh a a probe to make contact. the the initial data point that was going to be captured is is the local orbit going to change from 17 centimeters per second to something else. Because by making contact, going back to our car analogy, if you're in two-lane highway and you're one car and you swerve to the right and make contact with the other car, your momentum in
AstrophysicsOrbital MechanicsPlanetary DefensePrecision Measurement