WEBVTT

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GEORGE DILLER: This is Pegasus Launch Control at T-25 minutes, 5 seconds and counting. With us now in the Mission Director's

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Center is our project manager from the Goddard Spaceflight Center for ST5, Jim Slavin. Dr. Slavin, welcome, and I guess this is a

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moment of anticipation for you, because once the spacecraft has separated, why, you're, what you've been working for some time for

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is off and under way. And we'd like you to tell us something about that now. We've got some animation that will walk us through the

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launch sequence with the Pegasus and then run into the science. So, if we could roll that tape, Dr. Slavin, if you'll explain about ST5.

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DR. JIM SLAVIN: OK. You're looking at the initial drop that starts ST5 on its way into orbit. The total duration all the way through

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to deployment of the last spacecraft is only 16 minutes. Each of these three stages burn for two or three minutes. So it's actually quite

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quick. That was the fairing coming off. As soon as they clear the atmosphere, you no longer need the fairing to protect your payload.

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There we go, we've got the top stage now. So this is the last. And we should be in our initial orbit. And they're doing these rotations.

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These rotations are to keep the sun from shining just on one side of the payload, and maybe making the metal on that side expand to

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the point where something might bind. So we've got two of the three spacecraft out of the way.  Another thermal roll, keep the

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temperature nice and even. There goes out the third one. Now the appendage that you see coming off of the spacecraft, that's the

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magnetometer boom. These spacecraft, no matter how clean that you make them, they still perturb the local magnetic field a little bit.

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So you like to have your magnetic field sensor as remote as you can from the body of the spacecraft. Now there's the sun, that's the

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source of all the space weather systems that permeate the solar system. It just, it just underwent a coronal mass ejection, and that's why

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you see all of that ionized gas streaming off of the sun. Now those lines, those lines of force you see emanating from the Earth, that's

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the Earth's magnetic field, and it gets kind of stirred by this interaction with the coronal mass ejection.  And you saw the, you saw the

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magnetic field lines basically being, we would say eroded and pulled back into the tail, and so you get this, this intense circulation.

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And as a result of that, you wind up with, you could say secondary space weather systems being spawned, actually within the geomagnetic

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field. One of them produces the auroras, and that's actually what ST5 is going to be investigating, exactly how the magnetosphere

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drives those auroral lights. What you're looking at right here is one of the modern numerical simulations, or computer models of the

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magnetosphere. Those clouds, those colored regions upstream, that was actually the bow-shock. That gas comes off of the sun so fast that you

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actually, the Earth actually has a sonic boom, if you like, that forms all the way around it. And that's what they were trying to

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represent there.  DILLER: Tell us a little about the so-called "lights-out" part, where the spacecraft's kind of on their own. How does

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that work?  SLAVIN: Well, that's actually one of the more exciting aspects of the mission, from a technical standpoint. You'd like to,

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ideally we'd like to have these little spacecraft be as autonomous as possible. In fact, some people, some engineers actually believe

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that one day we're going to be able to design these little spacecraft so that they're smart enough that they may never need intervention

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from the ground. But we're not there yet. So, at the level of technology we're at right now, we hope to leave the little spacecraft on

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their own for periods of time at least up to one week. We may even go a little bit beyond that. It's basically a measure of the ability of

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the spacecraft to diagnose and correct anything that might go wrong or anything that the environment might do to them.

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DILLER: Now, are these, is this happening with autonomous commands on the spacecraft, or is the ground station computers, are they

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doing this on their own, or is it some combination?   SLAVIN: It's a bit of a combination. The spacecraft can only store so much data.

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So the entire time that the lights are out, which just means there's no human present, there's no human supervision, the spacecraft are

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going to be identifying science events. Whenever they do identify a science event, they are going to be storing the data. And that data

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has to come down, and the ground system is going to, again, autonomously decide that it's time that some of these spacecraft need to

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be milked, so to speak. And that data needs to be taken down in order to make room for, to collect data for more events.

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DILLER: Well, Jim, thank you very much. And I think you're, you're about to have a very exciting three months and most of this will

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be going on at Goddard, I gather. Is that correct? Goddard Spaceflight Center?  SLAVIN: Yes, Goddard Spaceflight Center is the lead

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for this aspect of the mission and you're absolutely right, it's going to be really exciting.  DILLER: Jim, thanks very much. At 19

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minutes, 50 seconds now, before the launch of Pegasus and ST5, this is Pegasus Launch Control.

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