|Swift Webcast: Spacecraft and Launch Preparation|
Question and Answer with Chuck Dovale|
Tiffany Nail: Thank you, Omar. Chuck Dovale is here with us now to go over the final preparations of the launch and to answer some of your questions. Chuck, thanks for joining us.
Chuck Dovale: Thank you, Tiffany. Thanks for having me.
Nail: Chuck, could you tell me how things -- I'm sorry -- How are things looking as we prepare for the Swift launch?
Dovale: I sure can. Things are ready to go. As you all, as you're probably aware of, Swift has been at the Cape for quite awhile. It's been a very patient launch team. It's had to endure two major hurricanes coming through the area as well as competing launches: one on the east coast and one on the west coast. So, it's been quite awhile for us to get ready to launch, but I can tell you today that we are ready to go. We are completed through all of our launch readiness reviews. We're not working any issues at this point. We've loaded the second stage with propellant and the NASA, Boeing, and the Air Force team are ready to go.
Nail: Great. Could you also take us through the final phases of the vehicle preparation and launch.
Dovale: Sure. I would like to describe how we got to this point. I have a quick videotape that describes the processing if we can roll that.
OK. This is the Swift first stage. It is being hoisted into the mobile service tower at Complex 17. It's about 86 feet tall, 8 feet in diameter, weighs about 225,000 pounds. Boosters are hoisted into the tower and then the tower is rolled towards the launch mound, as you see there. Booster provides 200,000 pounds of thrust.
There is one of three solid rocket motors going up into the tower. They are used to augment the first stage thrust. Each solid is 43 feet tall, three feet in diameter, and weighs about 29,000 pounds. They each produce about 100,000 pounds of thrust. There's a picture of them being attached to the base of the booster. Here's a shot of the fairing halves, the composite material, 10-foot diameter fairings. They are being cleaned in this view and then a black/white inspection just to verify the cleanliness.
There's a shot of the fairing halves being hoisted at the complex into the mobile service tower and they will be used at a later date; once the spacecraft is mated, they will be installed around the spacecraft. This was occurring on October 4.
This is a shot of the second stage. It's about 20 feet tall, eight feet in diameter, weighs about 15,000 pounds and its thrust is almost 10,000 pounds. It contains, or will contain, a hypergolic propellant, meaning its propellant that will ignite on contact and propel the second stage to orbit. Here it's being mounted onto the inner stage of the launch vehicle. This is the Swift spacecraft coming out in its environmental-controlled transport can, wrapped in an inner bag, as well.
Swift weighs approximately 3,265 pounds and is 20 feet tall. This is the morning of November 8 in preparation for a November 17 launch date. Goes into the white room, as we call it, of the tower where it is brought in and unbagged and sat down on top of the second stage, as you see there. You'll see the transport can unbagged there and now they're removing the segments out of the can, exposing the bagged Swift spacecraft.
We'll unbag the Swift spacecraft and then bring the fairings in and install them around the spacecraft. There's a shot. One side of the fairing is already installed and here is the other side closing in. As it's closing you'll get one last view of the Swift spacecraft. Just a little bit about the countdown. Actually, this evening we are going to have a weather briefing at 8 p.m., just to ensure that the weather is safe to roll the tower. And the rolling of the tower will occur between 1 a.m. and 3 a.m. tomorrow morning. The countdown is approximately 12 hours in duration, although the total countdown is about 4 hours. So, the senior management will come on station at about 8 a.m. tomorrow morning.
The countdown has two built-in holds and we've also got a one-hour window, which is a little bit unusual for NASA launches. So, we certainly welcome as much time as we can to get the launch off on time. And we're planning to do so at 12:09 tomorrow.
Nail: OK. Chuck, you have so kindly agreed to answer some questions from our NASA Direct viewers about Swift, but before we do that, we'd like to mention that one lucky question board participant will be winning a mission gift pack. I'll announce the winner at the end of the webcast. Let's get started.
Nail: Our first question comes from Marc from Bowie, Maryland. He wants to know: Why is a Delta II rocket being used for the Swift payload and, also, could you use a Delta IV rocket for this kind of a payload?
Dovale: OK, Marc. Good question. I'll answer the second part first. Yes, we could use a Delta IV if we needed to, but the way I look at it, to use a Delta IV would be like if you had a dump truck and you filled it halfway with cargo to deliver to its destination. You could do it, but is it the most economical way to go about it? Not really. So, that's why we chose the Delta II. And just a little background as to how we choose rockets for our launch services program. We choose them basically on three criteria: performance, cost, and previous history or past history. Performance -- can it list the spacecraft weight and deliver it to the proper orbit? Does the spacecraft fit onto the rocket? Does it fit in the protective shroud, the fairing? So those are things we ask about performance. Past history -- has the rocket been performing well on its previous flights? Has it had any failures? What caused the failures and have they been fixed satisfactorily? So we look at that. And then we also look at cost. Does the cost of the launch service fit in the mission's budget? Is it the best deal for the taxpayers? So, those are things we look at for every mission and, in all cases for Swift, the answer came up that the Delta II was the right fit. It is the workhorse of our fleet.
Nail: Marc also has another question: How long does it take for the solid rocket boosters to separate from the Delta II rocket? Also, can you tell me why is this being launched from SLC 17A?
Dovale: OK. There are three solid rocket motors, as I mentioned before. They're all lit from the ground and they will burn for 63 seconds, and three seconds later we will separate them to get rid of unwanted weight, basically. The other part is: Why Complex 17A? And actually, the three solid configuration for Delta II can only go off from Pad A. The Delta II with three solids actually lifts off a little bit slower then the other configurations on a Delta. So, there are concerns on other pads for possible recontact because it's lifting up a little bit slower. So, Pad A gives us the best chance and minimizes any kind of recontact while launching.
Nail: Our next question comes from Junichi: In terms of observing gamma-ray bursts, what is the most advantageous orbit for Swift? Could you tell me Swift's orbit?
Dovale: OK. Good question. Swift's normal orbit is expected to be circular, 600 kilometers by 600 kilometers, or 325 nautical miles by 325 nautical miles, inclined to the equator by 22 degrees. The most optimal orbit for viewing gamma-ray bursts, I'm told, is anywhere from the equator to 25 degrees. So, Swift obviously fits in there, being at 22 degrees. And this affords Swift the greatest chance to examine the widest, clearest part of the sky.
Nail: Our last question comes from Ed from Los Angeles. How is the envelope, or window of opportunity for launching, determined?
Dovale: OK, Ed. In Swift's case, as I mentioned, the window is an hour long, which is almost unheard of in my world. Typically, we have instantaneous or one-second windows, or something very tight, because we are either trying to catch up with another satellite or we're trying to catch up with another planet, you know, and needing some escape velocity. So, in Swift's case we are pleased that we have an hour window to work with. The reason that is, is Swift is viewing a wide spectrum of the sky. It's viewing about one-sixth of the sky at any time. So, it was not vital that we had a tightly prescribed launch window. The main driver of the one-hour window was driven by thermal constraints. They wanted to deploy the arrays in sunlight, so the project made sure that within their one-hour window, their spacecraft was only rotating 15 degrees in that one hour. And that gives them plenty of time to deploy the arrays in sunlight so they can be power positive, where the arrays will be charging almost instantaneously.
Nail: Chuck, thank you for all your insight and being with us today. Good luck on launch day.
Dovale: Thanks. Thanks for having me.
Nail: I mentioned earlier, we have a question board winner to announce. The winner is Ed from Los Angeles. Ed will receive a mission gift pack. Everyone else whose questions were read will also receive a prize.
That's the end of today's webcast for Swift,:a mission to study gamma-ray bursts, but keep checking with NASA Direct! for details about our next mission, Deep Impact, set to launch on December 30. Thanks to Delta weather officer Joel Tumbiolo, launch manager Omar Baez and launch director Chuck Dovale for joining us today.
Don't forget, you can track the Swift launch from a live virtual launch control center beginning tomorrow morning at 10:30 Eastern time. I'm Tiffany Nail and we'll see you next time.