Planetary Radio: Space Exploration, Astronomy and Science - The Pioneer Anomaly: Changing the Laws of Physics?

Episode Date: September 10, 2007

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Closing in on the Pioneer Anomaly, 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. Why aren't Pioneers 10 and 11 where they are supposed to be? We'll check in with Slava Turashev, head of the Pioneer Anomaly Project, which is almost ready to release 30 years of mission data to

scientists around the world. Emily Lakdawalla will take a somewhat reluctant look at the end of the Cassini mission, and Bruce Vance will join us for a what's up look at the night sky, punctuated by science fiction silliness, and a Betts will join us for a what's up look at the night sky, punctuated by science fiction silliness, and a new space trivia contest. Just a couple of headlines from around the universe. By the time you hear this, Cassini will have completed a flyby of one of Saturn's

strangest moons. In fact, with one side black as coal and the other quite bright, Iapetus is one of the strangest bodies in the solar system. Bruce will have more to say about it during What's Up, and next week we'll talk with a Cassini scientist about the close encounter. Check Emily's blog for the latest news. She's at planetary.org. Our image of the week is also at planetary.org. It's a shot that looks out almost as far as the Hubble and Spitzer space telescopes can see,

just a billion or so years after the Big Bang. The big excitement is that you can make out itty-bitty galaxies. Current theory says it's these little guys with their young stars that later got together to form the big bruisers, like our own Milky Way. Here's Emily's Q&A. I'll be right back with Slava Turashev.

Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, what will NASA do with Cassini at the end of its mission? Personally, I think it's strange to focus on the death of a spacecraft that's only three years into a six-plus-year mission, but this question appears to be on many people's minds. So I asked Cassini project manager Bob Mitchell. He said that the mission's agreement with NASA headquarters is that they are officially not concerned about what happens at the end of the mission, at least not for now.

There's good reason for that. Because Cassini is only part way through its mission, a lot more discoveries are probably yet to be made, and some of these may affect the choice of the end of mission scenario. Also, there are as yet no mechanical problems that'll bring about the end of the mission anytime soon. The time to begin thinking about the end of Cassini will be when planning for Cassini's second mission extension gets underway early next year. So how might Cassini end? Stay tuned to Planetary Radio to find out.

Slava Turashev is a research scientist at the Jet Propulsion Lab. He and colleagues around the world would like to know why Pioneers 10 and 11 aren't where they're supposed to be. Launched way back in 1972 and 1973, the little craft have consistently fallen off course by about 5,000 kilometers or 3,000 miles per year. Is it because of some prosaic factor like more heat radiating from one side of the spacecraft? Or could it be that we don't know the laws of physics as well as we thought? Consider the recent discovery of dark matter and, even more recently, dark energy. The only way to find out is to conduct a painstaking review of ancient mission data,

a massive effort funded by the Planetary Society that is now almost complete. Slava, it is so good to have you back on the radio. And, of course, we want to start with a status report. Where do we stand on this project, the Pioneer Anomaly project? Well, it's nice to be back into the Planetary Society radio, and I'm very happy to provide the status report on the Pioneer Anomaly investigation. We had a very interesting progress recently,

and that's primarily relevant to the fact that we were able to recover most of the Pioneer 10 and 11 Doppler data. And that is a very unique achievement because no other mission in the history of the space science was able to collect all the data in one place for the entire duration of the space mission. For the Pioneer 10 and Pioneer 11, we were able to do so. For the Pioneer 10, for example, we have almost 30 years of data from the beginning of the mission to the very last data point received from the mission. And for Pioneer 11, we have almost 20 years of data.

So I'm talking about radiometric Doppler data. But in addition to that, we were able to recover a very significant amount of telemetry, which is just housekeeping information on electrical status of every instrument on board, on power. 114 sensors were installed on both of those vehicles, Pioneer 10 and Pioneer 11. Talk about the Doppler data, because I know that's particularly important to detecting what's going on with these spacecraft. Our previous analysis used only 11.5 years of Pioneer 10 data.

And so now we have increased the data duration. We should mention that we both have daughters watching us here today, and yours is sitting next to you, and that's who yawned a moment ago. I guess she's not interested in Doppler data. No, she's not, and she is four years and one month today. So it's like a little anniversary for her. Oh, that's wonderful. So, yes, going back to Doppler data,

it's a unique set of information which tells us the position of the spacecraft, the velocity of the spacecraft. And this is very important because Pioneer anomaly was discovered during the analysis of Pioneer 10 and 11 Doppler data. If the Pioneer anomaly is due to thermal mechanism generated on board of the spacecraft, we should be able to tell how much the thermal contribution actually contributes to the anomaly. And the longer the data we have, the more sensitivity we get in resolving this contribution. You mentioned to me before we started recording that, in fact, analyzing this thermal data,

you've actually made quite a bit of progress with that and have built a model. Yes. That, I think, is one of the major accomplishments for the last, I would say, year or so, because we were able to build a finite element thermal model for the spacecraft that includes information about geometry, about optical properties of the surfaces of the two spacecraft, essentially. And then we can use flight telemetry that we were able to recover for both of those vehicles. And flight telemetry, this is exactly the information on the status of these 114 sensors, This is exactly the information on the status of these 114 sensors, status of electrical charging of the battery, the status of power available through the RTGs, electrical and thermal. Radioisotope thermal generators.

Exactly, exactly. So we have all this information available, and we can benefit. We will greatly benefit from this information in studying the Doppler data. The idea being that you are in the process still of, or you will be when the data is complete, of eliminating these more mundane possible explanations for the anomaly. Yes. I think before Pioneer anomaly will take its proper place in physics, going from controversial status as it is today, we should be able to analyze and have a better understanding of how much thermal radiation on the spacecraft contributes to the onset of the anomaly. Because I think this is one of the major possibilities, that the Pioneer Anomaly is due to heat emitted by the anomaly. Because I think this is one of the major possibilities that the pioneer anomaly is

due to heat emitted by the vehicles. And so now with the amount of data and the sensitivity that we will be able to achieve with our models, we should be able to tell what percentage of the pioneer anomaly the thermal mechanism will contribute. Then we should be able to tell how much exactly, if there is a new physics, and what is the total contribution of thermal mechanism. How close are you now to having all of this data ready to begin analysis? We are in a very good status. We are in a very good state in terms of thermal analysis. I think in the next six months, we should be able to plug in the available flight telemetry and really understand

the thermal behavior of the vehicles. And then with Doppler analysis, we a little bit, we faced with a challenge. And the challenge was that the data that we recovered we had to condition the data what it means is that just take this in as a sort of as a big picture the pioneer spacecraft were launched with punch cards punch cards punch cards so in the 70s the computers in 70s uh many listeners probably remember how those computers looked like. Yeah. Major mainframe computers. And now we navigate the spacecraft with just desktop computers.

Usually what you saw, of course, when they wanted to show you a computer was a tape drive. Exactly. a picture just during the liftoff of Pioneer 10 where a number of navigators sitting in the room and looking at the magnetic tape and the stack of the punch cards with the top card saying, last card. So for those listeners who are familiar with punch cards, they would probably get some smile because, yes, that's what we deal with. And then taking this as, again, a big picture, it's 1970s. And now we are living in 2000.

And so in 2007, where our software evolved significantly from Fortran 66 to 77 to 99, now we use C++. And so those different software implementations are very significant evolution on the software. And it's not just obsolete software Slava Turashev has had to deal with. We'll hear more in a minute. This is Planetary Radio. Hey, Bill Nye the science guy here. I hope you're enjoying Planetary Radio. We put a lot of work into the 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.

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You can learn more about the Planetary Society at our website, planetary.org slash radio, or by calling 1-800-9-WORLDS. Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio t-shirt. Members receive the internationally acclaimed Planetary Report magazine. That's planetary.org slash radio. The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. JPL research scientist Slava Turashev is our guest.

He was just telling us about the challenges presented by long-obsolete software and data formats, but ancient computer hardware has presented yet another obstacle to completion of the pioneer anomaly project. There were several reincarnations of different navigation computers that were used for navigation. And so we have to be able to read not only the data, but also have to be able to reconstruct formats in which the data was read, written, and understood. Speaking of hardware, I have read that there is one mainframe left at JPL.

An old DEC, Digital Electronic Corporation, I think was what it stood for, which you hope to be able to get a hold of because it's like the last one available to run some of these tapes? At JPL, we are embracing technology as fast as we can. That is to say that if there is a new computer system that is available, we test it, and if we are happy, we embrace it and move on. So the DAC alphas that we used to navigate the deep space missions are no longer used for that purpose. But they used to understand legacy software and the data that was sent from the old missions such as Pioneer. And realistically, there is only one system left at JPL. So it is very important for us to keep this last remaining computer online, so to speak, because it is our gateway to understand the data that was received from Pioneer 10.

What this says to me as much as anything else is here is one mission or two spacecraft with this impressive effort being made to recover this long ago data. There are hundreds of missions where no such effort is being made to recover this long ago data. There are hundreds of missions where no such effort is being made. And I have to think an enormous amount of data that is basically lost to us. This is a sad lesson that we learned. And that sadness of that coming from the fact that, yes, Pioneer 10 got a significant attention, Pioneer 10, Pioneer 11, because of the Pioneer anomaly. So we were able to focus our efforts in extracting every possible available bit of information that was out there. So we collected files from JPL. We collected some files from other places like National Space Science Data Center.

And we're still missing some files. And I have no idea where to get these files, despite the fact that we mounted a very significant effort. So now coming back to other missions, I don't expect other missions would have a complete record as Pioneer is. Most of the files that would represent a certain mission would be either stored on local computers somewhere in the center. Let's say any center that navigates or manages this mission will be there.

The center equivalent of an attic in someone's house, maybe. You will be surprised. And those files are stored on magnetic tapes that are, you know, sensitive to temperature, humidity, and the storage is not very ideal. And it will be very difficult to read those tapes because you need to have a proper format, you need to have proper hardware, software to read those tapes. And the longer those tapes are not read, the less chances for anybody to actually get hold of those formats and to be able to understand.

So I guess what I'm saying is that I was surprised how much data is actually lost in the space exploration, because what data we are able to receive, taxpayers are paying a significant amount of money to support the deep space exploration. But then the data is analyzed by the team of investigators at the beginning of the mission. And then once the data is received, in maybe one or two years, the data is analyzed. But then very rarely that data is placed for public access. And who knows what of that data might have proved useful with new methods of analysis, with new theory, and so on. Talk about the international community of scientists, a small community, but it's there,

which is anxiously waiting for this data and, I guess, meets periodically. Right. Pioneer anomaly is actually a very interesting phenomenon that attracts an international community. We have a very significant group of people in Europe, in France, Germany, England, who are spending their time and they spend their money. They got some funding from their local space agencies and national science foundations, equivalents of those organizations. Those people are meeting regularly. They write papers. They try to understand the Pioneer anomaly. And the team of people that I'm referring to is called Pioneer Explorer Collaboration that meets regularly at the International Space Science Institute in Bern, Switzerland.

Last meeting was last February 2007. And the next meeting we are planning to have in the very end of February 2008. And so last time we were able to bring 35 people to that meeting. And realistically, this is a by invitation only meetings. There is a much more interest for other people to come to those meetings. But unfortunately, we are limited by the space available, sort of the room size available. But I imagine there are many more other researchers who would like to join us investigating the Pioneer anomaly. And once the data will be available, once the data will be conditioned and made easier to understand, then I think

we will enlarge our collaboration for many people to join and start working with us. And you're going to make that data available to anyone in the scientific community? Once we will make sure that this data doesn't have any errors. Anomalies. And what we refer to that as realistically, we need to understand this data in the proper context of hardware evolution, hardware on the deep space network. context of hardware evolution, hardware on the deep space network. You know, the DSN, the complex was built, commissioned, new stations were built, commissioned,

decommissioned, moved, earthquakes happened. So all the information about the deep space network evolution for the last 35 years had to be properly implemented in the understanding of the formats. And now we need to go back to the old logs, all these handwritten notes, and try to understand what was done back then in, let's say, in the early 1980s. So we need to properly understand, put it in the proper context, and correct for possible misrepresentation in the files. Once we condition the data, then we assemble entire data record in one place. And then this file, major file,

will be made available for the community. Excellent. And that description you just gave is such a good example of why this has taken the amount of time that it has and the effort that has gone into it. Congratulations on very nearly accomplishing this goal of conditioning this data so that it can be made available, as you said. I hope at the very latest we can talk again maybe right after or during that next session you'll be doing in Bern, Switzerland. Definitely. Thank you, Matt. And I should thank the members of the Planetary Society for the support

because without this support we will not be able to get the job done because it was a major contribution and major effort on the part of the planetary society supporting our effort. And without this support, this work would not be possible. Thank you. Thank you, Slava. Dr. Slava Turashev is a research scientist on the staff at the Jet Propulsion Laboratory, very close to where we're sitting now, outside of Pasadena, California. now outside of Pasadena, California. He also heads the Pioneer Anomaly project that is getting tantalizingly close to being able to make all that data available.

And we will, with any luck, once and for all know what's going on with the Pioneer Anomaly. We'll find out what's going on in the sky with Bruce Betts. It will be time for this week's edition of What's Up right after a return visit from Emily. I'm Emily Lakdawalla, back with Q&A. As Cassini's successful mission draws to a close three, four, or more years from now, the mission must decide what to do with the spacecraft. The last large spacecraft to orbit a giant planet, Galileo,

was intentionally plunged into Jupiter to ensure that it wouldn't crash into Europa and its potential biosphere, although there was disagreement about whether that was really necessary. Cassini may well dive into Saturn for the same reasons, although smashing into Saturn without hitting the rings first is a challenge. Cassini could also be sent on a collision course for one of the smaller and presumably lifeless icy moons such as Mimas or Dione, although Cassini project manager Bob Mitchell acknowledged that this may not be politically palatable. But scientists hope that this end won't come for a long time, if at all. In fact, one of the end-of-mission possibilities is to go out with a whimper rather than a bang. If the mission eventually decides that contamination of any moon of Saturn isn't a concern,

one option is to place Cassini into a stable orbit in the Saturn system, allowing it to monitor the long-term dynamics of Saturn's atmosphere and rings, and have occasional distant flybys of the moons for as long as they can keep the spacecraft ticking. Got a question about the universe? Send it to us at planetaryradio at planetary dot org. And now here's Matt with more Planetary Radio. Time for What's Up with Bruce Betts, the Director of Projects for the Planetary Society,

back in person from the Mars Society conference last week. Now we're sitting across the table at TPS headquarters. So welcome back. As always, lovely to see you, Matt. A little enthusiasm there. I mean, it's really nice to see you, Matt. Ah, give it up. At least it's nice to see your daughter.

That's right. Claire is here, and she's not going to say anything. You worked her in anyway. She already said she does not want to speak. She didn't say she didn't want to be mentioned. That's true. That's true. Nice being here, Claire.

Maybe we got some of the laughter. Tell her what's up in the night sky. Up in the night sky, you will find in the evening sky, Jupiter being the brightest star-like object. And you'll see it in the south. It is looking lovely. Always good with a small telescope, of course, if you want to check out Jupiter's moons, appearing as small points of light surround it. You can also see Mars rising around midnight and up high in the southeast before dawn. It is reddish, it is getting brighter,

and it will continue to get bright. It's to the left of Aldebaran, which is similarly colored, an actual star, but not as bright right at the moment. You'll also see Venus now in the pre-dawn sky if you look over there off in the east just above the horizon. Brightest star-like object there. And Mercury is a tough one, but it is in the deep glow of sunset. We go on to

this week in space history and I always like to mark this one for you, Matt. Lost in Space premiered in 1965. Best science fiction show ever danger Will Robinson danger danger Dr. Smith that guy really annoyed me but that's a whole other that's a whole other

discussion that's really not worthwhile he was the villain but anyway he was really good at it I know me too anyway on to something more significant Of course he did. He was the villain, but anyway. He was really good at it. Gosh, I hated that guy when I was... I know, me too. Anyway, on to something more significant. Mars Global Surveyor arrived at Mars 10 years ago. It almost made 10 years in orbit working.

It did make 10 years after its launch before finally giving out after, of course, having a much, much, much, much shorter primary mission doing all sorts of great stuff. Gave us a hell of a decade. It was. Now on to Random Space Facts! She couldn't help laughing. We're going to talk about Iapetus. Of course, there's some great things going on this coming week. We've got the Kaguya launch of the Japanese headed off to the moon.

Also, Cassini doing its one close flyby of Iapetus. Iapetus is a weird place. And we're going to try and cover that next week. So prepare us. Tell us about it. Which? Iapetus?

Iapetus. Oh, okay. We'll also have lots of coverage on the Planetary Society website of the Kaguya launch if you want to tune in. Someone in Japan reporting on it for us.

From there, Bud from Cassini, visiting Iapetus, a little weirdness about Iapetus. It's, of course, the highest contrast body in the solar system with one side very dark, as dark as asphalt, while its other side,

the trailing hemisphere, is really bright, kind of like other icy surfaces. And this is still kind of a mystery. People thought it was from dark Phoebe, but now the spectroscopy of Phoebe from Cassini doesn't really match right with the dark side. So we are still exploring the depths of the dark side of Iapetus. It's a giant black and white cookie.

Or as Emily says, it's the yin-yang moon. It's a weird place, and we'll talk about it more in future episodes. But now we should probably go on to the trivia contest. Was that the dark side you were doing there for a moment? I was trying to do the dark side. I know, it was pretty subtle. I am your father. I'm her father.

I'll put an echo on that, too. Okay, thank you. Did you want to scream, too too since it's sadly true for you no just oh we gotta just keep looking at the microphone don't look at her pay no attention all right we asked you dark shadows dark shadows that show was kind of creepy we asked you what do you call the darker central part of a planet's shadow which also usually comes up in the context of a lunar eclipse like we just had where the moon passed into that part.

How'd we do? We had one listener who will go unnamed who got it wrong, said, You're just cold-blooded. Penumbra. Wrong. It's the umbra, right? It is indeed the umbra. The penumbra is the lighter outer part.

The penumbra is if you're on the moon and you're looking up, then the Earth would be covering part of the sun. But the umbra is when the Earth is covering all of the sun. Craig Journet, a regular listener, pointed out that if you stand out on a sunny day, you can see that even we have an umbra and a penumbra, which I thought was pretty cool. We also, you know, we have our unofficial Planetary Society pastor, our chaplain, Reverend Brent, who said that he, you know, he knew there was a reason he learned all that Latin back in divinity school. And he mentioned not only umbra, but umbriferous, which means providing shade. That is a cool word. Isn't it? Umbriferous. Unfortunately, neither of them won.

Sadly, but proving the randomness of our process. We turn to Omaha, Nebraska for the random selection this week. Walt Burris, Walt Burris of Omaha, sure enough said it's the Umbra. And he's going to get a medium planetary radio t-shirt. Which is kind of sad since he requested an extra large. Yeah, that's right. But that's what we've got, folks. No, I'm just kidding, just kidding, just kidding.

All right, let's go on to this week's opportunity. What kind of animal? That's it? I'd just like to pause there. What kind of animal can eat a frog? Make me laugh. Elephant. You can't enter.

I keep telling you that. What kind of animal was launched into space by the U.S. on a V-2 and survived impact on august 31st 1948 this followed up a couple of rhesus monkeys that had been launched these are suborbital flights but meeting space by most definitions the one that was launched august 31st 1948 and survived what kind of animal was it planetary.org slash radio find out how to enter clearly not a monkey at least not a rhesus monkey. I'm not beyond trick questions.

But you wouldn't do that. You wouldn't do that to us. Oh, yeah, that's right. Apology accepted, Admiral. Impressive. Most impressive. Get that entry to us by the 17th of September. September 17, that's Monday at 2 p.m.

We hope it's your favorite animal. Everybody go out there, look out for the night sky, and think about being umbiferous for your friends. Thank you, and good night. Well, he's a shady character. It's Bruce Betts, the director of projects for the Planetary Society, and he does join us every week right here for What's Up. Well, he's a shady character. It's Bruce Betts, the Director of Projects for the Planetary Society, and he does join us every week right here for What's Up.

Next week, Cassini's flyby of Saturn's moon, Iapetus. Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week. Thank you.