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Aura Webcast: Michael Tanner, Aura Program Executive
Host Tiffany Nail: Our webcast of Aura: A mission to understand and protect the air we breathe continues live from Vandenberg Air Force Base in California! Our question and answer session isn't over yet. Joining us now in the NASA Direct! studio is Mike Tanner, the Aura Program Executive.

Mike, welcome.

Tanner: Thank you for having me. It's good to be here.

Nail: First of all, tell us about your important role in the Aura mission.

Tanner: Well, as the program executive from NASA Headquarters, I'm responsible for the overall programmatic and technical direction to help develop the Aura project.

The Aura spacecraft provides the essential services for operating the four scientific instruments over the life of the mission. Fully deployed, the spacecraft is about 15 feet tall, 7 feet wide and about 23 feet long, with a 50-foot solar array extended.

A team of integration and test specialists assembles the observatory and tests it as a system, simulating the launch and on-orbit environments as closely as possible. For example, the spacecraft is exposed to vibrations similar to what it would experience during launch. The four science instruments on Aura are the High-Resolution Dynamics Limb Sounder (which is also known as HRDLES), the Microwave Limb Sounder (also known as MLS), the Ozone Monitoring Instrument (also known as OMI), and finally the Tropospheric Emmissions Spectrometer (also known as TES).

The High-Resolution Dynamics Limb Sounder (or HRDLES) is an advanced scanning, 21-channel, infrared, limb-scanning radiometer, measuring trace gases, temperature and aerosols in the upper trophosphere, stratosphere and mesosphere. The instrument will provide critical information on atmospheric chemistry and climate.

The Microwave Limb Sounder (or MLS) is an advanced limb-scanning, emission microwave radiometer. MLS measures radiation in the gigahertz and terahertz ranges, which is millimeter and sub-millimeter wavelengths. In addition, MLS has a unique ability to measure trace gases in the presence of ice clouds and volcanic aerosols.

The Ozone Monitoring Instrument (or OMI) is an advanced nadir-viewing, hyperspectral imaging spectrometer that measures solar reflection and backscattered light in selected ultraviolet and visible regions. The instrument's 1,600-mile viewing swath is perpendicular to the orbit track, providing complete daily coverage of the sunlit portion of the atmosphere. OMI is Aura's primary instrument for tracking global ozone changes and will continue the high-quality ozone records done by NASA's TOMS instruments in 1978.

The Tropospheric Emmissions Spectrometer (or TES) is a high-resolution, infrared imaging Fourier transform spectrometer observing the thermal emissions of the Earth's surface and atmosphere, night and day. TES will measure, for the first time from space, tropospheric ozone and other gases important to tropospheric pollution, which is the air we breathe.

By 2006, Aura will be a member of a constellation of satellites flying in formation. This formation is referred to as the "A-Train." Flying with Aura in the A-Train are Aqua, Cloudsat, Calypso and the Orbiting Carbon Observatory. The French Space Agency, CNES, plans to send a sixth satellite, Parasol, to join the A-Train.

While each satellite has an independent science mission, these complimentary satellite observations will enable scientists to obtain more information than they could using the observations of any single mission.

The Aura observatory will be launched on a Delta II-7920 rocket from Vandenberg Air Force Base in California, into a near-polar, Sun-synchronous orbit of 438 miles. The spacecraft repeats its ground track every 16 days. Mission operations are based at NASA's Goddard Space Flight Center in Greenbelt, Md. The flight operations team at the operations center will command and control the Aura spacecraft and instruments, monitor the health and safety, and perform mission planning and scheduling.

Researchers, government agencies and educators will have unrestricted access to the Aura data by the EOS data gateway. Data seekers can search for and order data from any of the EOS satellites through the DAAC (Distributed Active Archive Center).

So you can see, building a spacecraft, getting it into orbit and having it collect and send us incredible science takes hundreds of dedicated scientists and engineers spending thousands of hours designing and testing it to make it all work beautifully. But you know what? It sure is a lot of fun.

Nail: Our first question comes from Junichi from Niihama-city. What is the most distinguished equipment or feature of the Aura spacecraft among a lot of ozone-layer observing satellites in orbit at present?

Tanner: Well, you know, we have a number of Earth-observation satellites in orbit -- roughly 17. By the end of the decade, we'll have almost 20. The thing that's most exciting about Aura is the fact that Aura is really a chemistry lab in space. For the first time, we're going to have a suite of instruments will to measure, literally, the air we breathe. As Dr. DeCola mentioned earlier, we have four really revolutionary instruments that'll be able to look at the actual air we breathe right now in the troposphere, as it's known, from space.

It's really this chemistry lab looking at the dynamics of the atmosphere, being able to look at the chemical makeup, that's really going to make this very exciting.

Nail: Our next question also comes from Junichi from Niihama-city. In spite of a lot of Earth-observing satellites, how come NASA is supposed to launch the Aura mission and spacecraft? He'd like to know why!

Tanner: That's a very good question, because you know Aura is the last launch of the EOS Program, which is the Earth Observation System Program. What we want to do is look at the Earth as a system from space. Now, we've taken measurements all around the Earth from aircraft, from the ground, scientists going out on boats, for example, doing field trips just like you do field trips in your biology class, for example, or your chemistry class.

Well, what we're doing is a field trip from space, and our last of the three flagship missions of the EOS Program is Aura. We started out with Terra, that mainly looked at the land; that was launched about four years ago. We had Aqua that was launched about two years ago; that was the second mission of the EOS Program and as the name suggests, we're looking at primarily the water aspects of the Earth as a system.

And now Aura is going to launch, looking at atmospheric composition, the air we breathe, the ozone, as Dr. DeCola talked about earlier, and also climate change. And the reason that's so important is because ? I don't know if you realize it or not, but in the last 50 years, the population of the Earth has doubled, so we now live among 7 billion people almost, and we're all still competing for the same amount of resources we had when there was only half of us. Not only that, but our grain yields, our agricultural crops, have tripled in the last 10 years; so we're competing for less resources, if you will, and we need to understand from a system, what are we doing to our Earth, and how can we continue to survive as a human race?

Nail: Let's go back to our questions from the question board. Our next question comes from Yavor from Swarthmore. How long will Aura remain in operation? How is NASA going to dispose of it after its mission is over? If it is simply left in orbit, as is common practice with other satellites, and will it just create more potential "space junk" hazards for future orbiters.

Tanner: Wow, those are good questions. Well, let's see, the first question, we've designed Aura to last five years with a goal of six. We have enough expendables on board though to last anywhere from seven to eight years. But if you look at the history of the way we've been building our satellites over the years, we have satellites that have been up there for about 10 or 15 years.

After the five or six year life, though, if we decide we've gotten all the science we could out of our chemistry lab in space, we have an orbital debris plan where we actually lower the orbit of Aura with our propellant that we have on board, and Aura starts to degrade and burn back into the atmosphere. By the time it hits our atmosphere, it will be completely depleted, therefore there will be no space junk left in space, as you're concerned about, and Aura basically burns up, and you'll see it as a shooting star one night about ten years from now.

Nail: Patrick from St. Paul would like to know: Will Aura be looking at Earth, or Mars?

Tanner: Actually, we'll start out looking at Earth, because it is an Earth-observation satellite. But as Dr. DeCola mentioned earlier, everything that we do here on Earth and everything we learn from Aura about our Earth's atmosphere will be great information that we can leverage when we start looking at Mars and other planets, looking for life, if you will. Because how we define life here on Earth will help us to define life on other Solar System bodies, on other planets.

Nail: Rich from Elk Grove: From what I read, the Aura spacecraft is based on the EOS Common Spacecraft design. What exactly is the EOS Common Spacecraft design? What other missions have used the EOS?

Tanner: Boy, I tell you, Rich has done his homework. The EOS common design is a common spacecraft that we design that we've used to build both Aqua and Aura. The EOS common bus, as we call it, is the bus that we use and you saw it in our video that we rolled earlier. We used it on Aqua and it was built by the Northrup Grumman Space Technology Company in Redondo Beach. It used to be the old TRW. We used that exact same design, that exact same spacecraft, to build Aura.

Now, the reason we did that is, we wanted to launch on the Delta II, to use the same spacecraft we know we can fit into the envelope of the payload fairing, and we adapted it for the other four instruments that we launched on Aura. And because we did that, we were able to cut the cost of our design by exactly one half from our Aqua design, which was extraordinary.

Nail: Wow. Our next question comes from Robert from Tucson. What main points could be made about Aura, that would stimulate the interest of young potential Earth scientists and engineers in our schools, that would like to get involved with NASA programs such as this in the near future?

Tanner: Wow, that's a great question because you know one of our NASA missions and visions is to inspire the next generation. And to build a spacecraft like Aura, to be able to build it, to be able to operate it and to be able to look at the science and determine what the science is telling us takes all kinds of people. We have people who have science degrees, people who are engineers, people who are math majors; but then we have people who are in public affairs, people who are writers, people who take photographs.

So, if you have the least bit of science inspiration in your blood, but you don't want to be a science or math major, you still can be involved with NASA, you still can be involved in any of the companies that build these kind of spacecraft. So, if you love this kind of stuff, no matter what you study in college, you can get involved if you like.

Nail: That is great. Billy from Miller: Will Aura be able to help meteorologists make more accurate predictions by watching the climate changes and the ozone?

Tanner: Absolutely. You know, one of the things that we want, one of the three major things we want to do with Aura, besides looking at the stratosphere and ozone, besides looking at the air we breathe, but we also want to look at how climate changes, what are the impacts on this Earth's system?

Right now, if you look at some of our weather satellites, if you look at the great work of NOAA and the EPA and some of our sister agencies, they can predict weather about three to five days ahead. You've seen the images on the Weather Channel, for example, of hurricanes coming to the east coast, or tropical storms moving to the west coast, and we can predict them from about three to five days. With the information that we're going to learn from Aura, and the modeling techniques and the science, we'll be able to predict even longer out, maybe seven, maybe ten days out, so that if you have a long vacation, you can plan it long in advance and not worry about the weather.

Nail: Our last question from the question board is from Azra from New York City. What kind of evidence from this mission are we expecting to find?

Tanner: Well, as Dr. DeCola talked about earlier, there are things that we are going to learn about Aura that we have not even dreamed about yet. You know, we have designed these instruments, these four revolutionary instruments, to do some very revolutionary science. But as always, when we start to look into the science and we start to look at the data that comes back, we always find a golden nugget somewhere, in almost every single mission we've ever done. So there are aspects of this mission -- we're going to be able to measure the air we breathe, for the first time from space -- there are aspects of this mission that we're going to find out about that we never even dreamed about. So, wait till the data starts coming down in about 60 to 90 days and we'll let you know.

Nail:: Mike, I had a couple of questions I'd like to ask you. The first one is, how long did it take to build Aura?

Tanner: Well, the actual time that it took to build Aura is roughly about four years. But of course, we've been in the planning of the EOS Program for about 15 years. So again, we learned a lot of things we did on the Aqua Program that helped reduce the time to build Aura.

Nail: How long will it be able to collect and send home science?

Tanner: We'll probably, like I said before, we designed it to last about five years and the goal is six. We'll be up there for a long time, as long as we keep the funding and the mission operations going, we'll be able to collect for a long time.

Nail: My last question is, what makes Aura different from NASA's other Earth-observing spacecraft?

Tanner: Well, this is the first time from space that we will be able to actually study the air that we breathe in the troposphere, which is right here, right outside, where we are. We're going to look at pollution like we have never looked at pollution before, and watch how it can transport across the continent.

For example, the air that we breathe in California, right here where we are today, tomorrow a farmer in Ohio is going to be breathing that very same air. Two days from now, the folks in Washington, D.C., will be breathing the air that we're breathing right now. So, if we don't take care of the air that we're breathing today, it's going to impact those folks in the Midwest, as well as the folks that are on the east coast, as well as all of our friends and neighbors that are on other continents. We know this happens; we've modeled it, and now we're looking for the explicit data that's going to give us all those golden nuggets that really will help our models be more correct.

Nail: That is so fascinating, and yet so true. Thank you, Mike, and thanks to all of you for those great questions!

Tanner: Well, thank you very much for asking me to be here, I really enjoyed it.

Nail: Two lucky winners are about to find out that they will be getting Aura mission gift packs. Gift packs include an Aura Mission Poster, patch, fact sheet and a lapel pin. Our winners for today's webcast are Rich from Elk Grove and Yavor from Swarthmore. Thanks to everyone who submitted questions for today's webcast. Stay tuned to the NASA Direct! Web site for future missions and even more chances to send us your questions and have them answered live on NASA Direct!

Don't forget to join our virtual launch control center at 1 a.m. Sunday Pacific time to see live coverage of the Aura launch.

I'm Tiffany Nail, and thanks for joining us on NASA Direct!.