WEBVTT

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JESSICA RYE: Joining us now is principal investigator for the mission, Dr. Vasillis Angelopoulis from the

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University of California-Berkeley. Good afternoon. We have a short animation video.

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If you'd like to talk over with us and tell us a little bit about the mission, that would be wonderful.

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DR. VASSILIS ANGELOPOULIS: I'd be happy to do that. RYE: Thank you.

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ANGELOPOULIS: Yes, indeed. This is the five-satellite complement of the THEMIS mission. The five satellites are equipped with,

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with instruments that measure the Earth's environment and the deploys to their respective positions in order to measure rapid

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and, in fact, explosive energy releases in the Earth's space environment.

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And by tracking those energy releases from one satellite to the other,

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they will be able to determine for the first time where they originate in near-Earth space.

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Those energy releases is something we call "substorms" in our field, and they're very important to understand.

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They're as fundamental for space physics as our storms and tornadoes are in order

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to understand large thunderstorms in meteorology.

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You can see here how the THEMIS spacecraft will finally end up in their final positions in space,

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and they're unique in the sense that they are, in orbit, they're multiples of each other,

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so they line up along this sun-Earth line as you see in this image now,

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and track the flow of energy in order to determine the origin of that trigger of the energy released in space.

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Now, where that energy originates, somewhere around half the way to the moon,

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all the way down to a sixth of the way to the moon, behind the Earth, along the sun-Earth line,

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it comes rushing towards Earth and energizes particles and creates large space currents that can be, on

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occasion, damaging to telecommunications satellites and the space radiation can be hazardous to humans in space.

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So, for this reason, we wanted to understand these elemental energy releases, these substorms,

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in order to better understand and predict eventually space weather effects that are important to us.

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RYE: So what kind of data are we hoping to get from these spacecraft?

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ANGELOPOULIS: The five identical satellites carry five instruments that measure electric and magnetic fields,

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as well as particles, electron and proton out in space. And when they measure those,

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they can then get a composite image, or picture, of the pressure waves and the, the heating mechanisms out in space,

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much like buoys out in the ocean track pressure waves and temperature changes of weather fronts.

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Now we're talking about space fronts, but really it's analogous to what meteorologists do on the ground.

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RYE: Well, I know we're looking forward, hopefully, to a launch this afternoon at

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6:05 and thank you for taking your time to join us today.

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ANGELOPOULIS: Thank you so much. RYE: At T-47 minutes and counting, this is Delta Launch Control.

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