Planetary Radio: Space Exploration, Astronomy and Science - The Pioneer Anomaly... Solved!

Episode Date: April 23, 2012

After decades of mystery and investigation, after the recovery of gigabyte after gigabyte of data stored in obsolete computer formats, the whatdunit surrounding Pioneers 10 and 11 has finally reached its conclusion.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

The Great Pioneer Anomaly, solved this week on Planetary Radio. Welcome to the travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. Now we know what was ever so slightly pushing the Pioneer spacecraft off the courses that Isaac Newton said they should be on. It wasn't some new twist on physics, but JPL scientist Slava Turashev will tell us how the answer will be useful to many current and future missions of exploration. Bill Nye the Science and Planetary Guy is just back from the annual National Space Symposium where he hobnobbed with his fellow space wizards. We'll get a report from him in a minute. And Bruce Betts will help me give away another Skype buddy video chat pack to someone who enters this week's space trivia contest. Here's Emily Lakdawalla to get us started

and she arrives with her new guide to craters on asteroid Vesta, currently being studied by the Dawn spacecraft. Emily, I love your cheat sheet, and I would just bet you that there are people at the Dawn project office who are enjoying this as well. Well, probably they are, although I think that the people on the Dawn project have a much more intimate relationship with these craters on Vesta than I have. project have a much more intimate relationship with these craters on Vesta than I have. I made this cheat sheet of images of some of Vesta's more interesting craters, and they are very interesting. They're unusual. Some of them have black streaks, some of them have white streaks, some of them have both. Some of them have sharp edges, some of them have dull edges, and some of them have both. It's really quite an amazing varied surface. And they all do have

names. And I kept on looking at this one particular black and white streaked one and thinking, God, I really ought to know the name of this one. And it's Cornelia. And hopefully with my cheat sheet, I will quickly learn that that creator's name is Cornelia. And I'll be able to discuss Vesta's appearance a little bit more intelligently in the future. They're all shown to scale. I wouldn't do it any other way, she says in the blog entry, which happens to be a blog entry for April 19, by the way. But not only that, they're all oriented properly and apparently more or less arranged geographically. Yeah, you know, if it's a cheat sheet, I might as well go whole hog and try to make sure that I can get as much information out of it as possible.

Really, if it's worth doing, it's worth doing right. Anyway, this is pretty cool. You should take a look at it. And by the time you do take a look at it, you may very well be looking at the Planetary Society's brand new, long overdue website, which Emily has devoted hundreds of hours to along with some of our other staff. What should we expect? Well, what you should expect is a website that looks spectacular. It's going to be very pretty. And of course, it's helped along by the fact that space images are themselves so pretty. We plan to make full use of that with the new site design.

The other thing that I am the most thrilled about, and it's kind of a geeky mechanical thing to be thrilled about, but my blog will finally have keywords. so that means that if you see a picture that you like of Vesta and you think gosh there must be some other pretty pictures of Vesta you're going to be able to click on a little link that's going to take you to all my blog entries on Vesta and I cannot tell you how excited I am about this stupid mechanical upgrade to the to the back end of the blog so stay tuned for that next week we've been working incredibly hard and it means that I haven't been giving very much attention to the to the front end of the blog in the last couple of weeks, but it's all going to be worth it. Yeah, it has really been an awesome effort and well worth the trouble. I've seen some of the pages, and oh my gosh, what a wonderful transition this will be.

And by the way, when she says next week, that's of our talking about it. It could very well be up by the time you hear this. You know what else may be up by the time you hear this? It could very well be up by the time you hear this. You know what else may be up by the time you hear this? The USA Science and Engineering Festival, which, Emily, I'm very glad to say, you'll be joining us in the booth in the Washington, D.C. Convention Center, Saturday and Sunday, the 28th and 29th of April.

It's free, but you'll also be with us again for Planetary Radio Live, Saturday evening at the National Air and Space Museum. It's going to be exciting. It's going to be busy, and I'll get to be a booth babe again, which is something I haven't done for a long time. Well, do try and make it by if you're in the area at one of these events, and say hi to Emily and the rest of us. She is the Science and Technology Coordinator for the Planetary Society and a contributing editor to Sky and Telescope magazine.

Emily, keep up the great work. I'll try, Matt. Bill Nye. Bill, I'm used to saying that you're just back from someplace. This time it's the National Space Symposium, and I am especially envious. Sounded like a really great event. Oh, it was great. COO Jennifer Vaughn and I went out to this high school, a middle school, where the Space Foundation has built a Mars yard with Lego rovers. It was just fantastic pedagogy, I thought, teaching techniques. And then

you meet everybody who's involved in building rockets and watching the Earth from space, making Earth observations. And a lot of people from NASA who were involved in planetary missions. It was fantastic. I was on a panel talking about the future of space exploration with Amy Meisner and Lisa Randall. These are people that think big about physics and deep space. It was really a great event. And moderated by Scott Hubbard, an old friend of the Society, right? He's a board member, full disclosure, and he's the Mars czar. He's the guy that is generally credited with turning the U.S. Mars exploration program,

getting it back on track. It was great having him leading the way. Didn't you also get to hang out with your old buddy, Neil deGrasse Tyson? Oh, yes. Neil threw out a big idea. Instead of having the NASA budget be four-tenths of a percent of the federal budget, he said, let's make it one percent. Let's double it, at least the NASA budget.

And that, of course, was very well received at this event. So when I was on the panel, I pointed out that the NASA 49, this letter that got circulated by 49 NASA employees and retired employees who don't believe in climate change. And this puts them at odds with other factions in NASA who are doing research revealing the relationship between humans and climate change. Oh, man. It was fun, though. And then the band comes out. so they played and I jumped up to the microphone for a few turns of phrase yes it was big fun it's quite a thing to discover a band named after you and what did you sing? you know when I met Thomas Dolby a few weeks ago

at the TED so it was a heck of a thing for the Planetary Society this week in Colorado Springs and next week is going to be at least as crazy an event at the USA Science and Engineering Fest. We hope to see a lot of you there in Washington,

D.C. It's all free. And we'll be there in force along with Bill Nye, the CEO of the Planetary Society. He'll be speaking in our booth and on the big stage and at Planetary Radio Live, which we'll be bringing to you right here on the show before too long, just a few weeks away. Thanks, Bill. Thank you, Matt. Up next, the Pioneer Anomaly, solved.

After years of reporting on the so-called Pioneer anomaly, have we reached the end? That's what it looks like. A paper published in the April 11 edition of Physical Review Letters says the mystery has been solved. That paper's lead author is Jet Propulsion Lab research scientist Slava Turashev. Slava and his colleagues are now convinced that the unexpected trajectories of the twin Pioneer spacecraft were not caused by some kind of exotic, unexplained physics. The real explanation could only be discovered thanks to the painstaking and often frustrating recovery of data stored in obsolete computer formats since the beginning of the Pioneer missions 40 years ago. It turns out the probes were slowing more than expected because of their

own heat or thermal radiation, some of it bouncing off the back of the big communication antennas that remain pointed at Earth. It's a revelation that will no doubt assist teams operating or planning other deep space probes. For more on the solution to this decades-old puzzle, I talk once again with Slava via Skype. Slava, congratulations. How long have you been working to figure out this mystery? Oh, Matt, thank you very much for your warm congratulations. congratulations. And I started working on this problem in 1996, together with John Anderson and Eunice Lau, who were at JPL. And John led this investigation beginning early 80s. And basically, I joined JPL and worked with John, started working with John on this exciting problem. So how does it feel to actually have now a solution that solves this problem, this anomaly?

You know, I felt responsibility of completing the study because I did recognize that I have the unique position in the sense that we at JPL have the data, we have the tools, we have expertise, and the community of experts and colleagues around the world who contributed to this work were very instrumental in this study. And if I personally would not continue with this effort, and Victor Toth would not play his role as he did, very instrumental role, and Victor Toth would not play his role as he did, very instrumental role, then probably we will still be chasing some unknown or new physics in this investigation. And honestly, it feels very good because almost 50, over the 15 years of my life,

I devoted to this anomaly, to the study of this anomaly. It was exciting, and then I feel very good that this study is complete. Now, wouldn't it have been even more exciting if you had come up with some new, strange physics, maybe some corollary of dark energy? Clearly, that would be an amazing outcome, and as we always said in the past, it would be a win-win situation because if the nature of the Pioneer anomaly would be revealing us something about new physics that we would be interested to learn, then this would be an amazing outcome. Because what Pioneer anomaly was is the apparent violation of the gravitational inverse square law. It's a violation of Newton's gravity even, not talking about Einstein's. And so then connecting it to other possible mechanisms of such a physics, such a new physics such as dark matter or other exotic possibilities,

that would be an amazing, tremendous outcome for the modern physics. But then also realizing that the standard physics that we know and we rely on in navigating our spacecraft and studying the solar system, if that standard physics that we trust still works, that's also a very good revealing result that we can now, we learned something along the way. We need to now, if you want to do some precise investigations in the deep space, we need to carefully account for every possible anomaly, such as the Pioneer anomaly, which is now related to the thermal mechanism. It's a photon rocket. In one of the interviews, we discussed sort of the analogous situation. if you drive your truck with your head beams on, what pioneer anomaly means in this case is that you have to account for the recoil force produced by the light leaving the high beams of your car, and so that your car will be diverting its

direction. So that's the very tiny force that is acting on your vehicle, but you would notice it. And so that's completely a complete analogy with the Pioneer anomaly, because the thermal force that was emitted by the radioisotope thermal generators. And so those thermal photons, which were living in the spacecraft, were pushing it very little, but very consistently for the number of years that it became obvious. It's an interesting study, very interesting, and I think we are very happy that we identified this, clearly identified this mechanism, and so we can put this story aside, but there are many lessons learned. It sounds like this is a gift, will be useful to other planners of very long duration, very deep space missions?

Clearly. Missions that attempt to measure tiny variations of space time, such as gravitational waves, mission to study gravitational waves, they will be sensitive to forces that we observed on the Pioneer anomaly. So in designing those instruments, one would have to account for the forces that we dealt with studying the pioneer effect. And so there are many other instances of such tiny forces. But that's all sort of, it's all tribute to the current level of technology that we rely on. Better technologies we have, the more precise measurements we try to make with them,

the more strange effects are coming into the picture which we need to learn about and account them in a future data analysis. And the Pioneer anomaly is a good example of that. That's JPL's Slava Turashev revealing the just-announced explanation of the Pioneer anomaly. He'll tell us more when Planetary Radio continues.

I'm Robert Picardo. I traveled across the galaxy as the doctor in Star Trek Voyager. Then I joined the Planetary Society to become part of the real adventure of space exploration. The Society fights for missions that unveil the secrets of the solar system. It searches for other

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That's the conclusion reached by JPL scientist Slava Turashev and his colleagues, who have been investigating this interplanetary mystery for 16 years. That's less than half the time Pioneers 10 and 11 have been in space. Both spacecraft are now headed out of our solar system, but scientists have long puzzled over why they are leaving us a touch slower than physics said they should be. The explanation turns out to have been the ever so slight but steady radiation of heat from the probe's own systems. Tell me, how important to reaching this conclusion was the recovery of this ancient data that at one point everyone thought we might never be able to recover? I love the word ancient. It's amazing.

It was space archaeology, in a sense, because the spacecraft was launched on punch cards. And today we navigate our spacecraft using c plus plus it's in terms of software hardware think about mainframe computers alpha dec alpha hps and all of this are hardware that used to process the data receive the data and process it and the data actually sent to us by spacecraft starting early 1970s, we were able to collect a significant fraction of it. Without this data, this investigation would not be possible. And as we all know that this data recovery was initiated by the Planetary Society, for which I'm very grateful to the members of the Planetary Society who miraculously gave a very helping hand contributing to our initial study. So thanks to the member of Planetary Society, we were able to collect not only Doppler data,

but we were able to collect also tele investigation of the Pioneer effect using all wealth of data that we were able to recover. Doppler data, which relates to navigation and telemetry, which relates to housekeeping, sort of the health of the spacecraft throughout the years of its flight. We covered a significant amount of data that was very instrumental in our understanding how the pioneer vehicles behaved through the years and how they contributed to the formation of a fact that we know now as pioneer anomaly. I love your reference to archaeology. I'm thinking of these ancestors of ours all of 40 years ago, managing to reach Jupiter and beyond thanks to punch cards. Right.

We jokingly refer to ourselves as Sherlock Holmes. You know, we were looking at some evidence of somebody else's, you know, smoking gun, and we were looking through, sifting through tons of data and looking through magnetic tapes and recovering the data, understanding the sort of the data, and we really were looking for something, for some pattern to emerge. And then little by little, this pattern emerged. And so the thermal recoil force, now we know a lot about it. It's not only one mechanism of the spacecraft, it's

actually two mechanisms, and there are some little ones as well that we're contributing to the force. And so we know a lot how these forces can be created. And this is, again, as I said, thanks for the new data that we were able to recover together with a member of Pantry Society. And I was just reading before we spoke the blog entry from April 19 by our colleague Bruce Betts that you contributed to.

In there, Bruce mentions another bit of data, well, more than one bit of data, over the course of this mission, which I wasn't aware of, but obviously played an important role, that you had a record of temperature from six sensors on the spacecraft itself. How important was this data? It's not just six sensors. I think when I was talking about the telemetry, essentially spacecraft had 114 sensors on the spacecraft. Really? Wow. So we have 40 gigabytes of data from the launch to the last data point for both spacecraft. And these 40 gigabytes of data contain the data streams

relevant to each of these 114 sensors. So those sensors were for the thermal sensors on the spacecraft, then the power dissipated within each instrument, then pulse counts for the propulsion system, the communication system. Every subsystem on the spacecraft sent to the ground controllers information about its health status. So for the analysis of the Pioneer anomaly, we actually used all this information. And most of the information that we relied on is relevant to the power and thermal information on the spacecraft. We use that actually to predict the temperature of the spacecraft

and the power dissipated by it through each point of their flights. So this data was very, very important. With only about a minute left, can you now say that with the data you've collected, that we pretty much have 100% solved the Pioneer anomaly? I think this data enabled us to study the Pioneer anomaly. I think this data was able, it enabled us to study the Pioneer anomaly. And what we were able to do,

we built a finite element thermal model for Pioneer 10. And the Pioneer 10 spacecraft is telling us that we don't need to account for, we don't need to invoke any new physics to explain the Pioneer anomaly. It is likely that the Pioneer 11 will contribute additional information about the

properties of the Pioneer anomaly, but already with the analysis of Pioneer 10 data, I think we can say that we understand very well what is the Pioneer anomaly. Slava, once again, congratulations to you and the entire team. Again, there is a great description of this in the Planetary Society blog.

It's an April 19 entry, which you may be finding either on our old website or our brand-new website, depending on when you look for this, but it should be easy to find. Please pass along our congratulations to all of the other folks who've worked on this for so many years. One might hope somewhere in the universe, Isaac Newton is smiling right now and thanking you for this result. Wonderful. Thank you, Matt. Thank you very much.

Our pleasure, as always. Slava Turashev is at the Jet Propulsion Laboratory. He's been there for nearly 20 years. He currently is a research scientist in the Astrophysics and Gravitation Group. He's been doing that particular job since 2004. But he has been leading this work to figure out the pioneer anomaly for much longer than that. And it has now been solved. Well, we'll see what else we can solve as we look at the night sky with Bruce Betts in What's Up.

So, Bruce, just moments ago we finished talking with Slava Turashev. You have been working on this project yourself for a lot of years, trying to coordinate between Slava and his team and the members of the Planetary Society and the rest of the world. So congratulations to you, too. Thank you. It's an exciting, exciting time after many, many years. And obviously, he and his team were doing a little more work than I on it, but I've been involved for many, many years. Tell us now about the night sky. Well, it all is moving away from us, but a little bit slower than expected.

I like to call it the night sky anomaly. Thank you. I knew to call it the night sky anomaly. Thank you. I knew it needed theme music. Now it's so much more interesting. But we do have Venus still cranking awesome high in the west in the evening sky, looking super bright. We've got Mars also high overhead in the evening sky, reddish getting dimmer. We've got Saturn rising over in the east just past opposition. Always a nice telescope object.

All sorts of good stuff. So tell us what happened this week in space history. It was the flight of Soyuz 1, the launch of Soyuz 1 45 years ago. It was the first flight of the Soyuz spacecraft, actually rendezvoused with Soyuz 2 in orbit. Very unfortunately, it crashed on return, causing the first ever in-flight fatality for space, Vladimir Komarov. It's a very sad story. I've read this narrative, which, you know, now that all this stuff has become public. And, you know, he was able to send a message to his wife. I mean, they were pretty sure that he was not going to be able to survive this. Really a tragic thing. Yep.

I should have come up with a happy one, but we will go on to a happy segment next, which is Random Space Fact. That was cheery. Thank you. Too much? No, no, no. You can never have too much cheer in your life. Speaking of cheer, it really has nothing to do with cheer, but the largest trans-Neptunian object, Eris, out there in the outer solar system, has 17 times the mass of the largest asteroid, Ceres. Those Kuiper Belt objects, those other trans-Neptunian objects, they've got some big guys out there compared to the asteroids. I'm still hoping that Mike Brown or somebody is going to find, you know,

something really hulking out there. Maybe it won't be a big Jupiter. He said we'd have found that already. But, you know, maybe there's a well chilled earth uh analog out there someplace that we will name matt that'd be cool well you know they've gone with quar war war war and maki maki and sedna and matt why didn't i think to suggest this to mike well you probably still have time all right we move on to the the contest. Speaking of Kuiper Belt stuff. Speaking of stuff coming from out there, what is the source of the Lyrids meteor shower?

Lyrids meteor shower just having peaked shortly before this radio show aired. And I have to make a little side comment. The Lyrids meteor shower, for being a mediocre meteor shower, I mean, it's, you know, moderate, and it had a new moon, has got a new great publicist. I did a radio spot, and I just noticed it got picked up a lot of places. So I think the big showers, the Geminids, the Perseids, they need to invest a little heavier.

I think they need to hire you, and I think you should get your usual 10%. Wow. That's brilliant. 10% of dust and plasma. Indeed. So what is the source of the Lyrids meteor shower? You know what's interesting? We got a lot of responses to this one. I was sure that Pietro Carboni had been a winner more recently than 2006, but that was the most recent that I could find. Time flies when you're having fun.

Especially in Chester, New York. And that's where Pietro sent in his entry from. He said it was Comet C-1861-G1, otherwise known as Comet Thatcher. It was indeed. Stuff, stuff, debris spewed out of the comet going into that comet's orbit. And this is when every year we pass through that debris stream. Not surprisingly, a lot of references to Margaret Thatcher in the responses to this. But my favorite came from Todd Yampole, who pointed out that the comet was discovered well over 100 years ago

by actress and comet hunter Meryl Streep, one of her lesser-known accomplishments. I don't think that's true. No, I don't think it is either. Oh, okay. Anders Borland said, no, it was A.E. Thatcher, by some odd coincidence, who discovered it on April 4, 1861, though I guess the meteor shower has been documented for thousands of years. Yep. At least I think it was 2600.

Wow. They've seen this one documented way back in history. In fact, I believe it is the first meteor shower which we have documentation for. Oh, cool. I'm sure people noticed before then. Maybe it was bigger 2600 years ago. Maybe, maybe. It was huge in Sumerian.

You know why? Because they had an agent. Exactly. You're kind of like the Green Lantern, you know? This is being passed down from generation to generation. So lay a new one on us. All right. We haven't talked about animals in space for a while.

What were the first types of amphibians in space? And what year did it or they launch? Go to planetary.org slash radio. Find out how to enter this amphibious question. You have until the 30th of April, Monday, April 30, to get us the answer to this one. And you know what? I think we're going to give away. Let me grab it.

this one. And you know what? I think we're going to give away, let me grab it, we are going to give away the second and last of our free talk and Skype buddy video chat packs that was given to us by Skype. So you have this cool set, webcam for you, a webcam for your buddy, your mom, you name it, a couple of headsets,

and 60 minutes of free international calls to telephones. All right, everybody go out there, look up the night sky and think about what amphibian you'd like to buddy chat with on Skype. Thank you, and good night. Is it possible that when the French astronaut went up on the shuttle, he brought frog's legs? He's Bruce Betts, the director of projects for the Planetary Society.

He joins us every week here for What's Up? Sacre bleu! Planetary Radio is produced by the Planetary Society in Pasadena, California, and made possible by a grant from the Kenneth T. and Eileen L. Norris Foundation, and by the members of the Planetary Society. I hope to see you at the

USA Science and Engineering Festival. Clear skies! Thank you.