Planetary Radio: Space Exploration, Astronomy and Science - Ulysses Mission Operations Manager Nigel Angold on the End of the Solar Polar Journey

Episode Date: August 25, 2008

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Traveling to the Sun with Ulysses, this week on Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. For 18 years it has circled the sun following a lonely path. Now the Ulysses spacecraft is nearing its end. We'll look back with Nigel Angold, Mission Operations Manager for the European Space Agency. Emily Lakdawalla will answer another of your questions in this week's installment of Q&A, and she'll get the job done in

barely more than 100 Martian seconds, while Bruce Betts will help you pick a new name for a Saturn, a Saturn car, that is, belonging to a listener. That will be right after we take a look at the current night sky. Bill Nye the Science and Planetary Guy is on vacation this week. We come to you as the American Democratic and Republican parties are finally making their choices of presidential candidates official. But how do John McCain and Barack Obama feel about space exploration and development? Fortunately, both have just issued space policy position papers. You can read them at planetary.org.

And I hope you know that planetary.org is the place to find what I firmly believe is the best collection point for all news planetary. Emily's space blog has put up links to some of Don Dixon's newest space art. You may remember that ace artist Dixon was a guest on this show a while back. Emily also provides her critique of Twitter in Space, or should I say, Twitter in Space. or should I say, Twitter in space. Turns out the Phoenix lander isn't the only probe using the ultra-brief online tool to provide mission updates. Ulysses was one of the first space exploration missions to depend on an international partnership.

The solar power orbiter was only supposed to last five years. Now, at 18, failing power is likely to spell the end of the spacecraft that showed us the north and south poles of the sun for the first time. Nigel Angold has been working on the Ulysses mission for every one of those 18 years. Though he works for the European Space Agency, his office all of that time has been at NASA's Jet Propulsion Lab near Pasadena, California. That's where I found him a few days ago. Nigel, first of all, thank you for joining us on Planetary Radio, and congratulations as a representative of the Ulysses mission,

which is going on 18 years of observing the solar environment. Yes, thank you very much. Officially, we were supposed to end the mission July 1st this year because we were expecting the hydrazine July 1st this year because we were expecting the hydrazine fuel on board the spacecraft to freeze. However, we've managed to keep it from freezing up until now, and we are continuing to take scientific data on a daily basis. So we are still going, although we are not sure how much longer we can continue. So the rumors of your death were greatly exaggerated, obviously.

Absolutely. And yet I was getting those releases. Apparently you guys were as surprised as anyone? Well, yes, I suppose we were surprised. But one of the problems we have on the spacecraft is that we don't actually have very good temperature monitoring of certain areas of the spacecraft. And where we are expecting the fuel to freeze is one of those areas where we don't have good monitoring. So although we can model the thermal environment

on board the spacecraft, we don't have absolute measurements where we really need them the most. So difference of a few months is quite usual for a particular event to occur. And in actual fact, we haven't ever had any good, hard data for freezing hydrazine because for 18 years we've been trying to avoid freezing it, and we've managed to do that successfully.

What is the outlook? I guess it's hard to say without that additional data. Well, the outlook isn't particularly rosy because in order to keep the hydrazine from freezing, we are actually flowing fuel through the pipes every two hours. We move shift fuel through a cold spot just a few centimeters at a time, but that uses up about a half a kilogram of fuel every month. So within a few months, if we don't freeze, we will actually run out of fuel anyway. So not very many more months to go.

You've been with us from the beginning. In fact, you've been here at JPL as a representative of ESA. Did you have even the slightest inkling, I bet you've been asked this a million times, that you'd still be here 18 years later with a spacecraft that's alive and kicking? Absolutely not. I mean, the mission was designed to last for five years, basically. We managed to do that very successfully. And then

bit by bit, we've been extending the mission a few years at a time. And now it's 18 years, and it seems remarkable that we've come this far. As we have found at Mars, as Cassini is finding in the Saturnian system, there are huge advantages in terms of science if you can keep a spacecraft out there for a long time. That certainly seems true with Ulysses. That's absolutely true for Ulysses. The beauty of a mission like Ulysses is it's making unique measurements because it's flying over the poles of the sun. It's the only spacecraft to do that and there are no plans for another one to do it. So it's taking a unique perspective of the sun. Because we have extended for 18 years, we've managed to go through one

11-year solar cycle and seen a reversal of the magnetic fields of the sun, which reverses every 11 years. So that's a 22-year cycle. So we've got about three-quarters of that so-called hail cycle recorded. Why do we go over the poles of the sun? And an analogy is that if you were limited to exploration of the Earth around its equator, you would never be able to see what was over the poles. You would think everything was covered in rainforest or whatever, but you wouldn't ever predict the polar ice caps. Just the old blind man and the elephant story. I don't know if that's a big story

where you grew up, but here, if you just feel one piece of the elephant, you don't know what's going on at the other end. Exactly. So the idea was because every other measurement was made essentially in the ecliptic plane where all the planets are and where all the other satellites are located, going over the poles of the sun would give us a different perspective. So we have three orbits of that. So we are measuring at each latitude three times as opposed to once and each time at a slightly different condition of the sun. And in fact, you were able to get through solar minimum and take it all the way to solar

maximum. I guess that was even lent its name, the solar maximum mission to the continuation of the Ulysses mission. That's right, yes. Prior to Ulysses, measurement of the solar wind was, as I said, based upon observations in ecliptic. And typically you would see a solar wind of around 400 kilometers per second, which is actually the slow solar wind. When you get up to higher latitudes, it's around 750 kilometers per second.

And these originate from the coronal holes. The high solar winds were thought to be unusual, and as it turns out, it's the slow solar wind which is the unusual. For the most part of the solar cycle, it's the high solar wind which is around for most of the time. We're not here really to talk science, because you're more on the engineering side, but I do want to at least mention about the magnetic field.

Ulysses also made some tremendous revelations about how that magnetic field is structured and its relationship to the magnetic field. Ulysses also made some tremendous revelations about how that magnetic field is structured and its relationship to the solar wind. Yes, essentially, I mean, there are two observations made. Firstly, I mean, the field reversal is kind of like just a dipole rotating, a bar magnet, if you like, rotating. So at one point, the north pole is facing upwards and then it flips so as it's facing downwards. So it acted very much like a dipole. But in other respects, the magnetic

field of the sun is more complex than was originally thought. So this will lead to new models of sun's magnetic field and hence the whole of the dynamics of the heliosphere. Back to the longevity of this spacecraft. Space is a nasty, nasty place. How do you design a machine like this, over-design it? In fact, I think you called it, Ulysses, an engineering over-achiever. Still, to be able to put up with those kinds of conditions for that long seems quite an achievement.

It's true. One of the things in our favor, I think, was the fact that in order to get out of the ecliptic plane and get into this unique orbit over the poles of the sun, we had to have a large amount of energy to change its orbit. We launched on board the shuttle, which got us into low Earth orbit, and then we had two very large booster motors. But even then, that's not enough to get us out of the ecliptic plane. So these booster motors took us out to Jupiter, and then we flew past Jupiter and used its gravitational field to sling us out of the

ecliptic plane. So it kind of tilted our orbit by almost 90 degrees by flying past this huge planet. But because we flew past a very big planet such as Jupiter, which has a very harsh radiation environment, the spacecraft had to be designed to cope with that. So you have to have radiation-hardened components. And that has meant that it's been a very robust spacecraft. On the other hand, given that we are dealing with a spacecraft

that was designed in the late 1970s and early 1980s, it's not terribly complex, and therefore, in some respects, it's not particularly adaptable to various different situations. We can't change lots of software on board the spacecraft the way you can with modern spacecraft. But on the other hand, it's very robust. There's not so much to go wrong, if you like.

Simple is good in many respects for spacecraft, and it's obviously done well for Ulysses. We'll hear more from Ulysses Mission Operations Manager Nigel Angold in one minute. This is Planetary Radio. Hey, hey, Bill Nye the Science Guy here. I hope you're enjoying Planetary Radio. We put a lot of work into this show and all our other great Planetary Society projects.

I've been a member since the disco era. Now I'm the Society's Vice President. And you may well ask, why do we go to all this trouble? Simple. We believe in the PB&J, the passion, beauty, and joy of space exploration. You probably do, too, or you wouldn't be listening. Of course, you can do more than just listen. You can become part of the action, helping us fly solar sails,

discover new planets, and search for extraterrestrial intelligence and life elsewhere in the universe. Here's how to find out more. You can learn more about the Planetary Society at our website, planetary.org. Here's how toorg slash radio. The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. After visiting Jupiter, the Ulysses mission has been circling our sun pole to pole. And Mission Operations Manager Nigel Angold has been watching over it. After 18 years, the spacecraft is finally running down. In a sense, you're up against a wall.

The spacecraft is finally running down. In a sense, you're up against a wall. There's nothing you can do about the decay of that little piece of plutonium in the radioisotope thermal generator. But otherwise, mechanically, is this spacecraft still in pretty good shape? The spacecraft mechanically is in excellent shape. The only problem we've had mechanically with the spacecraft is the mutation anomaly which we got when we first deployed an axial boom, which was part of one of the instrument experiments.

It was an antenna. This antenna is illuminated by the sun, and as the spacecraft rotates, it flexes. It's kind of like a bimetallic strip, if you like. And because it flexed, it transmitted motion into the spacecraft body itself, and that caused the wobble or mutation. Now, this was a problem because we have a high-gain antenna on board the spacecraft because the transmitter on board the spacecraft is not very large, not very many watts,

and therefore you need a big antenna in order to get data back from the spacecraft to earth and this antenna has to be a big power it's a big parabolic dish it has to be pointed very accurately at the earth and if the spacecraft wobbles then the pointing of that antenna is compromised and you lose your data that's really the only issue we've had fortunately we found some techniques which we could use to damp the mutation by firing thrusters on board the spacecraft in an unusual way. This phenomenon occurs once an orbit as we come into perihelion as we get closer to the sun, and it lasts for about a year. So we've had three periods where we've had this problem to overcome,

and we've managed to keep this wobble down to low levels so that we've managed to have essentially a complete data set, a continuous data set from beginning of the mission until now. I want to turn to your experience. You are an employee of ESA, the European Space Agency, and yet you have spent 18 years here in the wilds of Pasadena, or actually La Cunada, Flint Ridge, where JPL is really located. That just strikes me as such an interesting cultural experience. It can't have always been fun to be so far from home.

I'm not so sure about that. I think it's always been quite a lot of fun here. In the early days, there were a number of cultural issues to resolve, and not so much actually living here but working here, different ways of working between both ESA and NASA or JPL, some very clear cultural differences, which over time we've worked through and we now have an extremely nicely integrated team.

But in the early days, there was not necessarily friction, but the way things were done from the JPL side didn't quite mesh with the way things were done from the ESA side. But from the point of view of living in Southern California, well, I wouldn't say it's too much of a hardship. I think there are worse places in the world to work and live, so I'm not going to make it out like I'm in any real hardship here. No argument from me. I'm a native. This really was, though, I think, a pioneering mission in many ways, one of them being that it was the result of this international

collaboration, which nowadays is almost far for the course, instruments from various nations and agencies ending up on one spacecraft. But that also seems to have been sort of a pathfinding role for Ulysses. Do you get that sense? Yes, it's true. I think we were one of the early missions to be involved with international collaboration on such a large scale. To some degree forced upon us by the fact that originally the program was two spacecraft and one of the spacecraft was cancelled and one was meant to be a US spacecraft and one was meant to be a European spacecraft that all got combined into one so we have an odd mix of operations where the spacecraft is provided by Europe for the most part but the radioisotope thermal thermoelectric generator was provided by

the US space shuttle discovery which is obviously provided by the US, tracking provided by the Deep Space Network, and operations done by a European team located at JPL. It's a very strange mix, but yes, we were pioneers in that regard. And also, it's been made a lot easier, I think, by the fact that we have grown up into the age of the Internet. Certainly, I think we were one of the first missions which actually used email as opposed to faxes as its primary interface with its scientific community. We weren't originally using the Internet, but eventually, obviously,

our interface with our community became through the Internet as opposed to trying to find files on a server somewhere. It has evolved. International collaboration has become a lot easier from a logistical point of view. Politically, sometimes it is, sometimes it isn't, but I'm not going to get into that too much. That's not one you can engineer away, unfortunately. Not true. But I would have to say that on a working level, I've been very lucky to have been in an international environment all my working life.

That's a privilege. Are you headed home once that hydrazine freezes up? And we've heard from Ulysses for the last time. That's an interesting question. The only answer I have is another question, and that's for me, where is home? I don't know that yet. I will figure that out in the next few months. Well, I hope it's not a decision you have to make for a very long time, and that Ulysses continues to do what it has done for nearly 18 years, and that is

provide really groundbreaking science data back to all of us here on Earth about the sun. Thanks so much again for joining us on Planetary Radio. Thank you very much. It's been my pleasure. Nigel Angold is and has been over the entire course of the Ulysses mission, the mission operator. Were you mission operations manager from the start?

No. How did you start out? I was the spacecraft operations manager from the start? No. How did you start out? I was the spacecraft operations manager. Ah, well now he's the mission operations manager, still working for the European Space Agency, but based here at the Jet Propulsion Laboratory outside of Pasadena. We will be back with this week's edition of What's Up? and our friend Bruce Betts after a visit from Emily with this week's Q&A. Hi, I'm Emily Lakdawalla with questions and answers.

A listener asked, If a Martian's sol is 40 minutes longer than an Earth day, yet they still use a 24-hour clock, how long are Martians' seconds? When do they use the Mars clock and when do they use the Earth clock? Most space missions operate using Earth time based on universal time. Spacecraft computers are equipped with clocks that count up the seconds of mission elapsed time, and all spacecraft operations are conducted according to this internal clock using Earth seconds.

The steady ticking of the spacecraft's own clock prevents confusion about when events are planned, particularly when most missions operate so far from Earth that there is a lag of minutes or even hours between the time that signals are sent from Earth and when they are received by a spacecraft. In addition to spacecraft time, landed Mars missions also have to keep track of local solar time. The local rising and setting of the sun influences power availability, causes changes in lighting for images, and is related to daily weather changes, all of which are important. So mission planners keep track of local solar time using the 24-hour clock that they are familiar with. This works well for Mars, whose days, minutes, hours, and seconds are only about 3% longer than Earth ones. The mission's plans are organized according to this local solar time, but before commands are sent to Mars, they are converted to spacecraft clock time. So for the most part,

the rovers and Phoenix don't know what their local time is, except in one instance. Opportunity keeps track of the number of clock ticks since local midnight in order to wake up from its deep sleep power conservation mode. Got a question about the universe? Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio. Time for What's Up on Planetary Radio. Bruce Batts, the director of projects, is here, ready to tell us about the night sky and come up with the name for kirby runyon's car we we have all the candidates not a whole bunch there weren't a lot

but their choice their choice their choice as spencer tracy said in woman of the year welcome it's good to see you it's lovely to see you. It's lovely to see you, Matt. Night sky, Jupiter dominating the evening. Check it out, rising. It's up in the east in the early evening, south by middle of the evening. Check it out, ideally, with a telescope. Look for those little dots that represent the Galilean satellites, the big moons of Jupiter. Even with steady binoculars, you can see that. That's the big thing to look at. We went from where I just was reading off 6,000 things to do to where things are a little thin.

So check out some of those constellations. Also, let me remind people, I can't tell you when you can see a satellite going by, an Earth spacecraft satellite, because we've got listeners all over the world, and it's rather specific. But you can check it out on websites, including www.heavens-above.com and look for things like the International Space Station, Hubble Space Telescope, looking like bright lights passing over in the night sky and you can predict exactly where they'll be when. On to Random Space Fact! Okay, it'll do.

You're tired. I am a little tired, I'm sorry. Did you want me to try again or just train for next week? You can do it quickly, yeah. I mean, just really... Yeah, just train. Just start working out again. Come on.

All right, I will. Just these Olympics, ironically, have been tiring me out watching them. So I haven't done my usual 30 minutes a day training saying random space fact. All right. Well, it's time to get back on the bike. All right. Random space fact. Mars.

The Phoenix mission. I was just talking, including with my kids, about the mythical Phoenix, which, of course, bursts into flames. I can guarantee you the Phoenix spacecraft will not be able to burst into flames on the Martian surface. And that is because Mars has no oxygen. To be more accurate, it has no molecular oxygen. And so now it's possible that the Phoenix, like some rocket repellents, got to keep those rockets away,

rocket propellants includes an oxidizer within the bird itself, but I don't the spacecraft does not, so minus the oxygen in the atmosphere the free oxygen molecules. No bursting into flames most of the Martian atmospheres of course. Carbon dioxide

which has lots of oxygen atoms, but totally not helpful for making fire, which is why it's used in fire extinguishers. I wonder if that Journal of Irreproducible Results is still out there, because that would be a great piece for them, wouldn't it? You know, a hypothesis on how the Phoenix, the chemical structure of the Phoenix bird. Oh, that would be.

Wouldn't that be cool? That would be nerddom at its best. Mark that one down. All right. All right. Just a second. Okay. Marked it down. On to the right. Just a second. Okay. Marked it down.

On to the trivia contest. He didn't really. Gosh, I can't get away with anything with you. On to the trivia contest. And, of course, last time we asked you to name a car. Not just any car. As we have never done. Indeed.

Listener Kirby Runyon has bought a Saturn brand car and wants to name his car after one of the moons of Saturn. So we did one of our occasional creativity contests, inviting people to submit names, not only names of the moons, but also reasons why it should be named that. Take it away, Matt. Here's one from Thomas Janukta in Poland, Warsaw, Poland. And this is one I don't think you'd heard of. I certainly had not. Kiviuk. Very elegant orbit.

11,111,000. In other words, 111,000 kilometers. Interesting Inuit name. Easy to pronounce. Kiviuk. Apparently it's not easy to pronounce. No not for me. It's not for you. Not for yours truly. I'll go with something a little shorter here. Steve Witte a regular listener from Michigan suggests Iapetus because not all decisions are

black and white but he says his Saturn is white with black interior and of course Iapetus being the high contrast object in the solar system, one side white, one side black. Yeah. And Tom Hendricks also put Iapetus in. He said because especially if the car is two-toned and way out there, he says. I've got a couple more. I've got Enceladus. Okay.

And because it would be the water-powered comes standard with really cool tiger stripes. And it's plume wonderful, that. Plume wonderful. I love that. It's plume wonderful. That from Rick Qualls, Texas. I got one more, and it's from Lindsay Dawson, our friend from Down Under, who sends us candy. Well, this time he sent us a poem.

Here it is. Ain't no why when a car is named. Cars, they are, just all the same. Saturn's moon for Saturn's name is only certain to inflame. This is what its name will be, one from Norse mythology. Herokon, wolf-riding

hag of winter storms. With this name, your car is born. I do enjoy the wolf-riding hag of winter storms. And another norse uh god apparently from uh torsten zimmer ymir why mir ymir uh however it's pronounced translates as gravel yeller which is good so that's something a car would do so he says you imagine starting it up on a gravel road creating a crunching sound, and heading off into the distance.

Sounds like a good commercial for Saturn right there. So what did Kirby think of all these? Kirby went through all of them. So who's our winner? He gave them very careful consideration. And after doing so, he liked Iapetus. And he particularly liked Steve Woody's entry, Steve Woody from Michigan. But now Tom Hendricks did come up with the same moon. so I think we may have to give out two posters this week.

Well, that's very nice of you. That's fair. I think it's fair. All right. I'll charge you for the second. But congratulations to all of our entries. They're delightful, and we really appreciate it. And, you know, for those of you who weren't quite up to coming up with a name for Kirby's car, we're going to give you another chance now. No car naming this time. We're going back to solid facts. And in this case, we're going back to a Planetary Society mission from a couple of

years ago. Planetary Society tried to fly the first ever solar sail mission, Cosmos 1. Unfortunately, suffered launch failure. Had nothing to do with spacecraft, had to do with the rocket. But tell me about Cosmos 1. How many blades did that solar sail have? So if they had been able to deploy it, how many blades would the solar sail have had? Go to planetary.org slash radio. Find out how to get your entry to us and try to win another glorious Explorer's Guide to Mars poster.

And get that entry to us by 2 p.m. on Monday, September 1st. 2 p.m. Monday, September 1. We're done. All right, everybody. Go out there. Look up the night sky and think about turtles with socks on. Is this something you were just doing with the boys? That was an input from the boys.

I solicited what people should think about, and that's what they came up with, Turtles with Socks On. I think it's a good thing to think about when you look up the night sky. Thank you, and good night. Oh, wait, that's your line. Thank you, and good night. He's Bruce Betts, the director of projects for the Planetary Society, crawling our way with Socks On for another edition of What's Up.

They're so quiet when they're on. Next time, a great new guide to the night skies for amateur astronomers. Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week. Thank you.