Nail: Now that we've learned a bit about the mission and heard from members of our launch team, we're pleased to introduce our final two guests.
Steve Pszcolka is the NOAA-N observatory manager for NASA, and Bill Mazur is NOAA's polar satellite acquisition manager.
Steve and Bill, welcome to our webcast. Bill: Hello Pszcolka: Thank you. Pleasure to be here.
Nail: Steve, let's start with you. NASA and NOAA are partners in the Polar Operational Environmental Satellite Program with NASA
responsible for designing and launching the satellite. Can you tell us a bit about your role at the observatory and what your
responsibilities are for this mission? Pszcolka: Being observatory manager for NASA has got to be the best position in the world.
I work with a talented group of individuals, both at NASA Goddard Space Flight Center and at Lockheed-Martin Space Systems Company.
I lead the spacecraft team, multi-disciplined group of engineers. And I work with Lockheed-Martin both as independent review and side by side
in somewhat of a badgeless environment in the fabrication, integration, tests and launch of the spacecraft.
Nail: Thank you, Steve. Bill, NOAA's role in this partnership is to manage the operational side of the program which includes
as I understand it, global weather forecasting, wildfire detection and several other services.
Can you tell us about your involvement with this mission? Mazur: I'd be happy to talk about some of the exciting applications of those data,
a list of which grows just about every day. Today we don't call them weather satellites any longer.
They're environmental satellites, but certainly weather monitoring and forecasting is still a very important part of our overall mission.
Today, nearly all weather forecasts originate from a bank of state-of-the-art super computers at the
National Center for Environmental Predictions in Maryland.
And 99 percent of the data that goes into those numerical weather prediction models comes from satellites, most of it from POES.
Next, other importance is the whole host of remote sensing applications that monitor from the top of the atmosphere down to below the ocean
for coral monitoring and other applications and everywhere in between, temperature and moisture, ozone, up high.
All of the data that's collected for that purpose is used for a variety of applications in near real time as well as longer term,
climate-type activities. And all of it is archived at the National Climatic Data Center in Asheville, North Carolina.
And there it's available for long-term studies to evaluate trends and data.
And last, but certainly not least, are the real-time applications. Our imagery is monitored by thousands of ground stations around the world.
They use it to monitor hazards, such as volcano eruptions, of course, severe weather and fires, as you talked about.
Additionally, we have the search and rescue application you heard about, which has thrust NOAA into a new role,
one of being the coordinator between detecting people in distress and making sure that the proper authorities are monitor
-- are notified to send people out for rescue. It's a very gratifying program to be part of.
Nail: Thank you, Bill. As you know, the NASA Direct question board has received numerous questions from people all over the world.
So with your help, let's try to answer some of them. Bill, our first question is for you. It's from Rich, from Elk Grove.
Current weather satellite images I see on TV fade a lot when the sun drops over the horizon. Will the NOAA-N
and its six channel imaging radiometer make these images clearer with and without sunlight?
Mazur: Well, what Rich is referring to probably are imagery from GOES, time lapse images, in the visible spectrum.
Those images are particularly good for monitoring and observing the buildup of thunderstorms in the afternoon.
But, unfortunately, when the sun sets, the picture gets darker. NOAA-N carries an imager, the advanced, very high resolution radiometer
that has three infrared channels in addition to three visible channels. The infrared channels allow you to monitor clouds
and everything that has a temperature, both day and night. Additionally, it's got a one-kilometer resolution in the infrared,
which is quite a bit better than the GOES satellite. Nail: Our next question is from Junichi from Niihama City.
I've been wondering whether or not we will be able to lengthen the life of satellites forecasting the weather of the Earth.
Is NOAA-N equipped with much advanced devices capable of producing enough electricity to run the battery systems
of the satellite longer than NOAA-M? Mazur: Well, actually, battery power isn't the weak link in the lifetime of our satellites.
Mostly, our experience shows that mechanical mechanisms like scanners tend to wear out soonest.
Because of that kind of problem, we've made several important changes to NOAA-N. The scan motor on the imager, the AVHRR ,
I talked about, has been replaced with a powerful new motor, which should last much longer. Our tape recorders,
digital tape recorders that we used to fly on previous satellites have been replaced by solid state recorders
that have more capacity and will last a lot longer. Our moisture censor, the microwave humidity sounder is an updated,
new instrument that should provide much longer lifetime than the previous instrument.
Additionally, the launch vehicle we're on, as Omar talked about, the Delta II, is a much more accurate rocket and will put,
place us into a much better, more stable orbit. So the satellite will be more useful for a longer time.
Nail: Our next two questions are for Steve. First one comes from Rich from Elk Grove. The NOAA-N satellite has tons of equipment on it.
How was each of the instruments tested before launch? How much bandwidth does the NOAA-N use in sending information back to Earth?
Pszcolka: You're right, Rich. Good question. There is quite a lot on this spacecraft. There are 8 science instruments on the spacecraft.
And they are the boxes that support the data collection system and the search and rescue system.
There are additional boxes that make up the spacecraft subsystem that's needed for operating the spacecraft.
There are 16 antennas on this spacecraft as well. Many of them transmit, others receive. Those that do transmit to the ground,
they have different data rates, different frequencies, different output power.
Defining a bandwidth, addressing the bandwidth part of your question, really isn't a practical thing for this spacecraft.
We have frequencies that range from UVF all the way into S band. So you talked about the instruments.
And that's a big part, because there is a challenge involved in testing instruments on the ground. You have to put it in the right --
have the right operational conditions as well as the right stimuli to produce a meaningful result from the instrument.
We receive our instruments from vendors - vendors from across the United States as well as from Canada, France and from EUMETSAT in Europe.
And each of these programs -- these test programs that the vendors do have certain things in common.
And the environmental test campaign has similarities to it. But the instruments themselves are all different.
So the test program has to be tailored to it. We have instruments that measure in the visible, infrared, ultraviolet and microwave.
So in tailoring these, each of the vendors come up with test data and calibrate their instruments. Upon calibrating the instruments,
they give this data with the instrument as it's delivered to the spacecraft.
And let me take the spacecraft after populating it with the instruments and take it through environmental test campaign.
In the environmental test campaign, there is one test that probably closest emulates launch conditions and, therefore,
is a favorable operational condition for these instruments. And that's thermal vacuum testing. And that's where,
we actually take the spacecraft and put it in a very large chamber and we pump it down into vacuum. And we run --
but we run a systems test. Before we even get there, one of the standard tests that we run in environmental testing is
called a systems test. Performance test, electrical performance test for the spacecraft.
So we run that at ambient. And then we put the spacecraft in a chamber, we pump it down into a vacuum.
We have targets in the chamber that are known sources, calibrated sources that we have a predicted result for the instruments.
And we then cycle the spacecraft through hot and cold plateaus. In this case we run three each, three hot and three cold.
And we run the systems test at these plateaus And we collect that data. We take the data that the vendor had at his facility
and we match that against the data that we had in the environmental test and at the spacecraft level. And we look
to make sure that everything operating (out there is) fine and predict the performance of the instruments on the ground.
We then hold on to that data and we create trend data from it. And when we launch, we have an operational verification of these
instruments once it's on orbit. They come on at various times. And we use the data that's coming down,
that's telemetered to the Earth and we match that against the data that we received at the spacecraft level against
the vendor data that's received when we first got the instrument, and make sure that the health and wellness of the spacecraft
or the instruments are operating perfectly. Nail: Our next question comes from Junichi from Niihama City.
What is the weight of NOAA-N? How much electricity is needed for NOAA-N to observe nominally Earth and polar orbit?
How long is the duration of NOAA-N? Pszcolka: Junichi, good question.
At first glance, when you talk about weight, you think that it's just an interesting factoid.
But it's actually a very important value to have. And we accurately measure the weight of the spacecraft.
We need to because we need to tell the launch vehicle how much mass they're actually lifting so that ensures that they
inject us into the right orbit. The mass for this spacecraft, it weighs 3,149.34 pounds.
You talked about the electricity. Yes. We have ten-panel solar ray. We have three NiCad batteries. We have the rest of the boxes
that make up the power subsystem. The worst case spec to the power subsystem is 915 watts, of which we usually use
about 700 watts for nominal operation. In the duration of the orbit, if you mean the orbital parameters of the spacecraft,
the spacecraft orbit period is 102 minutes, in which 72 are in sunlight and 30 are in eclipse of the Earth, in the darkness.
It is a sun synchronous orbit, circular, polar. The inclination is 98.7 degrees. And the altitude is 470 nautical miles.
If your question is a duration of how long they last in orbit, these spacecraft typically outrun their design life.
The number that we use for an operational center is 3.75 years,
although many of them last far longer than that and serve in a backup role in the fleet. Nail: Our next two questions are for Bill.
Junichi from Niihama City. What is the advantage of polar orbit weather satellites comparing to those in geostationary orbit?
NOAA-N is to be in polar orbit, isn't it? Mazur: That's right. It is a polar orbiting satellite.
The main advantage is that it can monitor the entire world versus for a geostationary satellite,
only less than a third of the Earth at a time. This makes the POES satellites an important resource for users worldwide.
It's also very important for weather forecasting, in that if you want to predict the weather more than about three days
in advance, you need information from locations thousands of miles away from the area of interest. And that requires
you to begin looking over vast areas, in fact; the whole globe is what is used.
Our polar orbiting satellites monitor the Earth actually twice a day as the Earth turns under it.
And since we have a two satellite constellation, a morning and an afternoon satellite,
we actually monitor the globe four times a day. Nail: Our next question comes from Joey from San Luis Obispo.
Do you anticipate the potential environmental data collected on this mission can help
accurately evaluate the hole in the ozone theory?
Mazur: Well, the ozone hole is quite real. It occurs over the South Pole in the wintertime, there about September in the year.
Almost every year it occurs. We've been mapping the ozone hole since 1984 when NOAA-9 carried the first
solar backscattered ultraviolet radiometer, SBV. There is a similar but lesser effect over the North Pole occasionally.
But the effect we believe is caused largely by the extreme cold in the Antarctic winter, coupled with chlorine
and other gases in the atmosphere that destroy the ozone. It's a complicated process and we're still learning more about that.
But that is the reason why an international convention some years ago established restrictions on chlorofluorocarbons,
Freon and other materials to prevent the formation of these gases that destroy the ozone.
The ozone hole should dissipate with time. It will be many, many years before we'll see a major improvement.
But it's a contribution. Nail: Thank you. Our next question comes from John from Capac.
Mr. Pszcolka, the testing of the spacecraft seems to be a never ending challenge.
What is the time frame of this project from when you first began on NOAA-N to the fruition of launch on May 11th?
Pszcolka: Good question, John. You know, when you get to this phase of the program, the focus is on the mission itself
and the science involved in it. You work for NASA, you think about being associated with the science of the mission.
Everybody wants to know what the spacecraft does and what data comes down to the Earth and what it's used for.
But there's a whole other work ethic that goes on with building the spacecraft, or at least getting to this point and launching it.
And there's a lot of talented individuals that work for NASA that work in integration and test.
When you look at integration and test -- I mentioned it before on the instruments you kind of have the same thing.
You go through environmental test campaign. But a lot of talented people work and put this together.
And for NOAA-M, back in '99 and 2000, we began integration for NOAA-N. And I caution you from doing the math on this
because it's not quite that simple. We traditionally on this program have multiple spacecraft in high bays at the same time.
Back at '99 and 2000, we had three spacecraft on the ground, in the high bay, which we were juggling working between.
So as we progress in time, then, we're moving these three spacecraft forward.
In 2001, we introduced the instruments. We integrated the instruments and we started the environmental test campaign.
The environmental test campaign usually has four major tests in it. I talked before about the system test,
which is something that we run either eight or nine times over the life of the environmental test campaign.
We also do dynamic testing, in which we literally take the spacecraft and we put it on top of a big shaker table and we shake it.
And we shake it in all three axes to make sure that the spacecraft can survive launch loads and check the integrity
of the boxes and the structure. We also put it in an acoustic chamber and we bombard it with sound waves,
again to check the integrity of the spacecraft. And we do thermal vac, as I mentioned before, with the instruments.
We have targets in the thermal vac chamber; we cycle the spacecraft through a number of different cycles, hot and cold,
both stressing the electrical solder joints, boards, all the connections, all the boxes.
And we're ensuring that performance is constant and consistent throughout the cycle of an orbit.
Also in thermal vac, we also are checking the subsystems on the spacecraft. Very important and very needed in order to maintain
control of the spacecraft and communication with the ground.
Fourth major test that's running in the test campaign is EMI in which we place the spacecraft in a chamber, it's a Faraday cage,
very quiet inside, and we turn everything on, all the transmitters, all antennas, all the boxes and we make sure that
the spacecraft subsystems, the antennas and the instruments all play well together and we don't have any radiated
emissions or any problems with the operation of the spacecraft.
Bringing us up to, from now, I guess from '99 to 2000, we delivered the spacecraft on the 20th of April.
We went into Aliveness test, which is not as comprehensive a test as the SEPET test that I talked about earlier.
This Aliveness test was run on the 22nd and went from the 22nd to the 24th.
Were we verified the operation and the Aliveness the spacecraft and the instruments.
And the last testing would have been on April 28th, which we did flight programs and stray voltage in which we
turned on the launch vehicle and the spacecraft and made sure of compatibility between the two, check out interfaces.
So from '99 to here in 2005, we're waiting to launch this thing. Nail: Chris from Little Rock.
Why does the POES and GOES satellite start out with a letter after their names and then change to a number after launching into orbit.
Pszcolka: Okay, letters and numbers. Yes, you do absolutely need the secret decoder ring, because you're not going to get there without it.
On the ground, we give them letters. And this kind of goes back to more of a contractual answer,
in that we have a series of spacecraft on this current contract. This series of spacecraft are Tiros N and they are -- and -- well,
I should say N is the 15th out of 16 spacecraft contractually under this. Way back when, we started giving them successive
letters on the ground. As I mentioned before, we have multiple spacecraft in high bay at the same time.
The letters differentiate between the spacecraft that are on the ground. In orbit, we give that a number. And in this case,
at thirty-nine and forty seconds, that separation from the launch vehicle, NOAA-N will become NOAA-18; the 18 representing
the 18th satellite in orbit for NOAA. Now, trying to match up the numbers and letters -- this is where you need the secret decoder ring,
because the first of the series of spacecraft that starts this numbering and lettering campaign actually had neither.
It was just called TIROS-N. So then A became six. And this is where it falls apart a little bit. A was the sixth satellite in orbit.
B had a launch vehicle failure; therefore it never made it to orbit and therefore never became a number.
Then C and D and the rest that followed suit, with D actually leapfrogging out, having some problems, didn't launch in the same sequence,
so some of the other letters came up first. Nail: Our next two questions go to Bill.
The first one is from Arvid from Oslo. Can you tell me about the European involvement with the NOAA missions?
Mazur: Sure Tiffany. Since 1978, we've been flying sensors from that have been provided to us from Great Britain, France and Canada.
More recently, though, we've expanded our international cooperation by signing an agreement with the
European Organization for the Exploitation of Meteorological Satellites, or EUMETSAT.
This is a coalition of some 20 countries in Europe. And together with NOAA, we're going to fly a constellation of satellites
in the future where Europe will be building their own polar satellites, the first of which will be launched next year.
They'll be providing three satellites and we'll be providing NOAA-N and NOAA-N Prime as our contribution to that program.
In addition to flying all our entire payload of instruments on that op., the Europeans will also be developing and flying a scatterometer,
a GPS sounder, a new ozone instrument and a very advance infrared interferometric sounder.
We're looking forward to that new data as well. The U.S. taxpayers should be happy to hear that Europe is going
to be paying for their entire satellite, the launch and they're also providing the microwave humidity sounder,
which we're flying on NOAA-N for the first time. So NOAA-N is actually inaugurating this new agreement.
And we're looking forward to the European's launch next year.
Nail: Next question comes from Harriet from Baton Rouge.
What information can we expect to get from the polar orbiting satellites and what is it used for?
Mazur: Well, that's a big question. I think you heard earlier from Karen Halterman some of the applications
and saw some pretty good graphics of some of the products. Basically, it's three dimensional temperature and
moisture information for the whole globe, imaging of land and cloud and forest fires, volcanoes, aerosols and vegetation.
We also have a space instrument that monitors electron and proton flux in outer space, we're monitoring ozone,
Earth radiation in multiple wavelengths. And then we're doing data collection from remote sensors that are unfixed and drifting,
or moving platforms on some animals that we track. You heard about search and rescue.
There are just hundreds of applications that aide in timely and accurate weather predictions,
climate monitoring and in many ways, saves lives and reduces property damage.
Nail: Steve, back to you. Our next question comes from Fortunato from Tuscany.
Are there any changes to the NOAA-N compared to the previous satellites and if so, what are they?
Pszcolka: Yeah, that's a good question. And yes, Fortunato, there are changes, many of them driven by technological advancements,
parts issues, component issues honorable performance or system contributing impacts, like the switch of a launch vehicle.
So we do have some things that are firsts. The IMS, the initial measurement system, it's new.
It's a ring laser gyro replacing mechanical gyros from the past. So this is a first flight for it.
We have the MHS instrument, the microwave humidity sounder that we were just talking about.
It's a new instrument for the NOAA mission, the NOAA-N mission. We have the MIU, which is MHS interface unit,
a box that allows the MHS to interface with the spacecraft.
Because of the switch of the launch vehicle, we used to be on and fly on Atlas and Titan's both of which were ballistic missiles.
So it would take us up and drop us off. So we had to fly ourselves into orbit. So we had a hydrogen system and an average kick motor.
And we flew ourselves into orbit, injected ourselves. We do not need that now because we're on a Delta II launch vehicle.
The launch vehicle will take us up and inject us right into orbit. So we don't fly the AKM. We don't have a hydrazine system.
We do have new nitrogen thrusters that we're flying for the first time.
With these changes, we have changes in flight software. Again, because we don't need to fly ourselves into orbit,
we have different flight software. I hasten to say not simpler but just simply different flight software.
There are a number of other minor things that probably aren't worth going into. I mean, we've made some changes to --
some STX transmitters. Batteries are now SAFT cells as opposed to Gate cells. I think I've hit the highlights.
per second that are coming down. This is free to anybody. It's a direct broadcast. And so with just a moderate
Nail: Okay. Mike from Mount Waverly. On which rev, at what time and on what frequency will the APT VHF transmitter be first turned on?
Pszcolka: All right. Good inside use of the terms and the lingo's. A rev means in orbit.
Orbit, first time go-around, first rev, second rev, so on. APT is automated picture transmission.
APT is selected two channels from the AVHRR instrument. This is reduced resolution telemetry: it's every third scanline.
The AVHRR has six revolutions per minute. This takes every third scan line, so it produces six scan lines per minute.
The APT uses two of these scan lines -- I'm sorry, per second; six cycles per second. So you have two scan lines
antenna and computer system, you can collect this data that is the footprint of the spacecraft as it travels overhead.
What rev, when -- what frequency? I am aware of the issue that pagers in England have somewhat of a problem with the APT frequency.
And we are sensitive to this issue. I can answer the question on what frequencies. There are two transmitters.
Transmitter one is 137.1 megahertz. Transmitter two is 137.9125. But I can tell you that on rev two, Fairbanks --
over Fairbanks at that 15:10:10 zulu we'll turn on one of those transmitters. It's scheduled to be transmitter two,
so that will be the frequency of 137.9125. But I caution you that I'm not in the operations and there might be
It was launched in 1991. Its AVHRR imager is still working just fine and it's very popular
problems with on orbit assets or other issues that might cause us to switch transmitters to a different frequency.
But for right now, that's the plan. Nail: Thank you, Steve. The last two questions are for Bill;
first one, Steve from Indianapolis. What is the oldest TIROS weather satellite still working?
Also, are there any of these weather satellites that are just turned off and could be turned back on and used to
provide additional coverage if needed? Mazur: Well, the oldest satellite we're currently using is NOAA-12.
with literally thousands of direct read-out users.
That satellite was actually called NOAA-D as Steve was mentioning, and its age is actually older than the launch date would imply.
In 1983 we had two satellites that had been built and ready for launch, NOAA-D and NOAA-E but NOAA-E
had the new search and rescue feature built into it. And we're anxious to get that into the orbit, so we launched it before "D"
and then NOAA-F came along with other instruments, Earth radiation budget and ozone instrumentation so we launched "F"
before "D" and "G" and "H" before "D." For awhile there we were thinking about giving the satellite to the Smithsonian
but finally in 1991 we decided to launch it and we certainly have gotten our money's worth out of it.
As far as other satellites that are turned off, when we finally decided to turn them off we want to prevent them from interfering
with other satellites later on, so we do try to permanently turn them off. But if they have any value at all,
we'll turn some of the transmitters off, and keep them running for as long as we can.
Nail: Our final question comes from Junichi from Niihama City. Regarding the weather forecasting mission of NOAA-N,
I'm anxious to know if the NOAA-N is able to catch up with the latest information on dangerous hurricanes
or typhoons which grow bigger and move very quickly. I'd like you to comment on this matter for me?
Mazur: Sure, the hurricanes and typhoons are a major focus for weather satellites, both geostationary and polar.
The geostationary satellites are particularly good for identifying fully developed storms and tracking them.
But it's the polar satellites with their high resolution radiometers that are capable of measuring conditions in and
around the storms, helping to predict the future development and the direction of the storms and do so with some level of accuracy
even weeks ahead of time. The interaction between various conventional weather systems is an area of continued interest, trying to
figure out how these storms will react to other large low-pressure systems and that sort of thing. We update the global
and regional models just about every year to improve the intensity and movement predictions.
Nail: Thank you both so much for being a part of NASA Direct broadcast
Pszcolka: Thank you. Mazur: Enjoyed it.
Nail: We really appreciate your answers and what you helped us learn about the POES program and the NOAA-N mission.