WEBVTT

00:00:00.000 --> 00:00:07.000
NAIL: Launch Service Program Launch Director Chuck Dovale joins us to talk about the Pegasus rocket preparation for flight.

00:00:07.000 --> 00:00:10.000
Welcome to NASA webcast, Chuck. DOVALE: Thanks, Tiffany. It's great to be here.

00:00:10.000 --> 00:00:17.000
NAIL: Chuck, you take us through the rocket processing flow tape and address how the Pegasus differs from other NASA rockets?

00:00:17.000 --> 00:00:25.000
DOVALE: Sure. If we could have the tape start. OK, this is a view of the aft end of the Pegasus in its vehicle assembly building.

00:00:25.000 --> 00:00:35.000
The technicians are working on the aft skirt, torqueing it down. The aft skirt holds the fins, as you see being installed there.

00:00:35.000 --> 00:00:46.000
The fins are responsible for controlling the Pegasus launch vehicle during the first-stage burn. Here's a shot of the stages being mated.

00:00:46.000 --> 00:00:57.000
This is the third stage and the second stage coming together. This operation occurred between Jan. 10 and 19 of this year.

00:00:57.000 --> 00:01:07.000
These are Orbital technicians and engineers you see in the photos, and it's taken about 100 or so Orbital and NASA personnel

00:01:07.000 --> 00:01:16.000
to process the Pegasus launch vehicle and ST5 spacecraft for launch.

00:01:16.000 --> 00:01:24.000
Here's a shot of the payload support structure and the three payloads for ST5.

00:01:24.000 --> 00:01:32.000
It's being mated to the third stage of the Pegasus. Again, this took place in the third week of January.

00:01:32.000 --> 00:01:41.000
Here's a technician going through black-light inspections, as the fairing, the protective shroud is being installed around the spacecraft.

00:01:41.000 --> 00:01:50.000
This protects the spacecraft during atmospheric conditions as the launch vehicle's burning.

00:01:50.000 --> 00:02:02.000
It's in a clean room in Building 1555 on North Vandenberg. This helps keep their cleanliness levels to the proper level for ST5.

00:02:02.000 --> 00:02:06.000
Here's the second half of the fairing coming in. It's coming into the clean room.

00:02:06.000 --> 00:02:17.000
It'll be cleaned and verified to a class 100,000 clean room. It's very important that we keep the instruments for ST5 clean.

00:02:17.000 --> 00:02:25.000
Technicians performing an alcohol wipe.

00:02:25.000 --> 00:02:31.000
Here's a shot of the L-1011 on the flight line, as it awaits the Pegasus launch vehicle to be rolled out.

00:02:31.000 --> 00:02:39.000
Pegasus was rolled out last Friday. You can see quite inclement weather, but there was enough break in the clouds for

00:02:39.000 --> 00:02:49.000
us to get the Pegasus out to the flight line and mate it with the L-1011. The L-1011 is jacked up so the Pegasus

00:02:49.000 --> 00:02:55.000
will fit underneath it, and in doing so, the rudder has to be removed so it would fit under that.

00:02:55.000 --> 00:03:03.000
The rudder is subsequently mated to the Pegasus afterwards, and then aligned.

00:03:03.000 --> 00:03:08.000
The combined systems test follows to make sure that the mating procedure was done correctly,

00:03:08.000 --> 00:03:18.000
and that both electrically and mechanically, the L-1011 and the Pegasus are operating satisfactory.

00:03:18.000 --> 00:03:26.000
And now we're back. I can tell you, so far the technicians are finishing their work today, and other than some weather

00:03:26.000 --> 00:03:37.000
issues that we have, all technical issues have been resolved, and we've got a review in the morning just to check on the weather.

00:03:37.000 --> 00:03:45.000
Right now, it's not very favorable, but we'll see what the, what the morning brings. As far as the countdown,

00:03:45.000 --> 00:03:52.000
it's a four-and-a-half-hour count, and technicians and the team will come to the control center about 1:30 in the morning.

00:03:52.000 --> 00:04:01.000
We're targeting a 6:02 drop. The plane and the aircraft will take off 58 minutes prior to that and go to its preprogrammed

00:04:01.000 --> 00:04:06.000
racetrack conditions and hopefully drop Pegasus and ST5 on time at 6:02.

00:04:06.000 --> 00:04:10.000
NAIL: Chuck, we have a couple questions for you from our viewers. DOVALE: OK.

00:04:10.000 --> 00:04:18.000
NAIL: Our first question comes from Mark from Bowie: How fast does the Pegasus travel after it drops from the L-1011?

00:04:18.000 --> 00:04:25.000
DOVALE: Good question, Mark. The L-1011 is traveling at 39,000 feet at about 500 miles an hour.

00:04:25.000 --> 00:04:32.000
It drops Pegasus and Pegasus goes into a freefall for about five seconds before the first stage ignites.

00:04:32.000 --> 00:04:42.000
The first stage will burn for about 77 seconds, and at that point, it's going about 5,700 miles an hour.

00:04:42.000 --> 00:04:47.000
Second stage will light and burn, third stage the same. At the end of third-stage cutoff,

00:04:47.000 --> 00:04:57.000
the vehicle is going 19,500 miles an hour. Just to put that further in perspective, that's about 5 miles per second.

00:04:57.000 --> 00:05:04.000
NAIL: Our last question is from Ikaika from Laupahoehoe: What kind of fuel is used to power the engines of the Pegasus?

00:05:04.000 --> 00:05:12.000
DOVALE: OK. The, the Pegasus motors are all solid-motor propellants, as opposed to liquid. If you've seen the space shuttle

00:05:12.000 --> 00:05:22.000
launch before, the space shuttle main engines are liquid but the two twin solid rocket boosters along the sides are solids and there's

00:05:22.000 --> 00:05:28.000
quite a bit of difference in how they burn. If you've, if you look at the shuttle main engines, the liquid main engines,

00:05:28.000 --> 00:05:36.000
they burn very cleanly, kind of like a blue smoke and flame. The solids are completely different. The solids are bound

00:05:36.000 --> 00:05:43.000
in a rubber compound. The fuel is bound in a rubber compound, and it actually burns quite dirty;

00:05:43.000 --> 00:05:53.000
it's like a burning old tire. So, you see that grey, billowy smoke. And another difference in solid motor propellants as opposed to

00:05:53.000 --> 00:05:58.000
liquid is once you ignite them, they burn until they burn out. There's no way of shutting them off,

00:05:58.000 --> 00:06:04.000
unlike a liquid propellant that you can shut down an engine. So that's the main difference.

00:06:04.000 --> 00:06:07.000
NAIL: Well, thanks for joining us today, Chuck, and good luck on launch day. DOVALE: Thank you. Thanks for having me.

00:06:07.000 --> 00:06:10.000