Fifty Years In Space: Listen to the lecture
The Open University's 2007 Annual Lecture by John Zarnecki reviews some nail-biting...
The Open University's 2007 Annual Lecture by John Zarnecki reviews some nail-biting moments from the first 50 years of mankind's journey into space
- Duration: 1 hour
- Published on: Tuesday 12th June 2007
- Introductory Level
- Posted under: Astronomy
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Can you believe that we have been in Space for fifty years? It's incredible. I find it hard to believe. Fifty years! But half a century ago a lot of people doubted that it could actually happen. In 1956, Sir Richard van der Riet Woolley was Astronomer Royal and Advisor to the government on Space. Everybody was listening very carefully to what he had to say on the subject.
"Space travel is utter bilge."
Which just goes to show – never believe the experts. The following year he might have thought very differently because on October 4
(space sound effects)
It had four aerials transmitting this characteristic sound and it orbited the Earth once every ninety-six minutes. A month later the Soviets are at it again when Sputnik 2 is launched. It's bigger. It carries more instruments and this time there is a dog on board – Laika. Although there is enough food and water on board for ten days we believe that Laika actually died within a few hours in Space when the insulation in the cabin failed. But Laika was a national heroine and the Soviets had put a living creature into orbit.
(space sound effects)
(space sound effects)
(space sound effects)
The triumphs, the disasters, the impossible achieved. It was a truly incredible time when one event could pull together entire nations in a breath-holding moment. I have to confess that for me it was the drama of the whole thing that grabbed me as much as the science and the technology of it.
Now I’ve called this lecture because, when I step back and think about it, despite all the fabulous technology, all of the testing that we do to make sure that things go right, sending missions across the Solar System is an incredibly risky business because we don't always know what the conditions are going to be like at our targets until we actually get there. That was certainly true in those early days and it’s still sometimes true today. Over the years as a space scientist, I have had my share of good fortune and bad fortune, with some great successes but equally the occasional problem along the way. And I would like to share some of those moments with you tonight.
Now, my first slice of good luck, I think, happened just to be growing up in the 1960s. It wasn't just the Beatles, the Rolling Stones, Pink Floyd,
So every Russian dignitary had to come and pay their respects. We were given the afternoon off school. Now most of my friends went off to play cricket or football, play with their Game Boys or whatever it was you did in 1961. But for some reason I decided to go to
But let’s just digress for a minute and ask ourselves, as astronomers, as planetary scientists, why is it we want to go up there? If we take a look at the sky – this is a picture taken by my colleague Phil Rosenberg from his back garden in Wolverton here in
But if, instead of going a few hundred miles south to a nice site, you actually go a few hundred miles up above the atmosphere, this is what happens. This is the same object taken from a telescope on a satellite. You are seeing much more detail there. You are beginning to see the structure in the Galaxy and that lane of dust in the plane of the Galaxy. Now, I have been saying “see the Galaxy” but when we say “see” we don’t always mean “see” – as we do with the eye – in visible light, because visible light is only a tiny part of the entire gamut of radiation that exists. There is radio, radiation, X-rays, infra red, ultra violet – many, many types of radiation – and these are conveying lots of information about objects in our Universe.
Now most of this radiation is absorbed by our atmosphere, which is great for us as human beings because a lot of this radiation of course is very harmful. But it's not so great if you are an astronomer. You want to see this radiation because it's telling you so much. So lets have a look at this Sombrero Galaxy in other radiation, in other light. This is an image in infra-red light, taken again from above the atmosphere. It's beginning to look a little bit different and that dust lane as we call it around the Galaxy is now glowing rather brightly. That’s the region in red because dust emits lots of infra-red radiation. Now here it is again, seen in X-rays. And now it's looking very, very different. That’s because normal stars and dust – they just don’t emit in X-rays. We are now seeing completely different objects and processes – in fact some of the most exotic and violent events in the Universe. We are seeing massive stars and we are seeing material being sucked into black holes, being heated to incredible temperatures. So by being able to see different radiation we see a whole range of different processes and different types of objects. Now remember, these images, these last few images, would be inaccessible from the Earth. So we need to go above the atmosphere. How? Well, we put our telescopes on orbiting satellites and get rid of the effect of the atmosphere.
Now, back in the seventies it wasn’t so easy I was a student then. There I was. Trying to look like John Lennon, I think. And there weren’t too many opportunities to launch satellites just for astronomy. So we did the next best thing, we used something called a sounding rocket. It's really a glorified Guy Fawkes rocket. You light the blue touch paper; the motor fires for about forty seconds and, if you are lucky, you go two or even three hundred miles above the Earth, above the atmosphere. And if you put your telescope on that and point it and do everything right you can do your astronomy in just a couple of minutes. Back in the early 1970s, after I got my degree, I found out that, if I went to
So I was riding the crest of that new wave of astronomy. So I signed up and I was given the task to build a particular x-ray telescope. This is what we built. This is called an x-ray spectrometer. What it was going to do was to take in x-ray radiation and to split it up into the different x-ray colours and analyse how many x-rays there were in each of those colours. We were going to point it at a particular object called a supernova remnant. This was a, had been a star. It had exploded cataclysmically, four thousand years before, and it threw out a vast cloud of material, which was still so hot that it was glowing – not in light – it was much too hot to emit light – it was emitting x-rays. And that was what we were trying to look at. So there we were at Woomera, a bunch of young scientists. Between us we had precisely zero years of Space experience. Luckily there were a couple of very experienced engineers on the project. I think they had been working for all of five years in space research. They were the veterans. Between us we got the instrument and the rocket to the launch pad. Now, in a minute I am going to play to you my recording of the last twenty-five seconds or so of the countdown. It's not a very good quality because this was an illicit recording. Woomera was a high security Ministry of Defence site so I had to smuggle the tape recorder in. Now, remember, this was my first ever launch. Let’s hear it. We were in a bunker about a hundred metres away, just under the ground,
and at about minus fifteen seconds I had to make a decision as to whether we would launch or not. I’ve just said “Gas Okay, Jackie”. So that was the Okay. I was terrified. Everything crossed. That’s ten seconds to go, I think. Fingers crossed, toes crossed. Five … It was absolutely fabulous! I mean that sound, that blast wave went through your body. The rocket is already three miles up. It went up with enormous acceleration. It got above the atmosphere. The x-ray telescope pointed at the correct source on the sky to an accuracy of about a hundredth of a degree. It was a very, very challenging task and it pretty well worked. Well, up to a point.
I should say the data was sent by radio link back down to the ground, to the receiving station. And that was lucky because our luck ran out on the way down. The parachute should have opened so that our payload gently floated down. We could have used it again then on subsequent flights. Well, the parachute never opened. The payload hit the ground at about a hundred and twenty miles an hour. It was a mangled pile of metal. Still, I was able to get one small souvenir from that flight and I have got it here. I managed to smuggle it back under my jacket and I would like to show it to you. (laughter)
This is the nose cone from the rocket. This is one of two nose cones that fitted over the top to give it an aerodynamic shape so that it could get up through the bulk of the atmosphere. It was got rid of at about forty seconds by explosive bolts and it sort of fluttered down and landed on the desert floor. And so I managed to get that back home. It looked rather good. It made a difference from all the Che Guevara posters on the wall that we usually had. (laughter)
So what happened? Four years of designing and building this and then analysing the data. What was the result? Well here it is. (laughter) You are speechless I know. (laughter) But to me this meant everything.
This is what we call a spectrum. To my colleagues not a high-resolution spectrum I admit. And the critical part, which I am sure you have noticed, is this bump. That was it. That was the detection of oxygen from this particular super nova remnant. It was glowing; the oxygen was glowing and giving out one particular x-ray colour. I was very, very proud of that. It was predicted but it had never been done before. An element had never been detected by x-rays from beyond the sun. And we did that. So this was published in a journal called , a very prestigious journal. And it is one of the papers that I still look back on with some pride. I can't say that about all the papers that I have written, I have to say. (laughter)
Now, every good lecture I feel, as we all know, has to have a picture of a kangaroo. And here is mine. (laughter) So why have I got a kangaroo? Well, rockets are actually quite dangerous objects. You know – lots of high explosive and there are all sorts of precautions that you have to take. And at Woomera they were very proud that in thirty years of operation they didn’t have a single fatality – well, at least a human fatality. There was one fatality and it was a kangaroo. Not this one. One of the payloads was found in the desert, was recovered, it was another mangled heap of metal. And about thirty meters away was a kangaroo – dead – absolutely dead. Not a single mark on it. And the assumption was that it had been sitting there, minding its own business and this rocket had crashed down a few feet away from it and the poor thing had died of a heart attack. Poor old thing.
Okay. Well, hopefully, the Woomera experience gives you some idea of how I fit in to the fifty years of space exploration. I had my first five minutes in space.
Now let me move forward a few years, in fact to 1978. It was hard to get jobs in the late Seventies in the academic world so I moved to a company called British Aerospace in
Now Hubble has been absolutely vital to astronomy because it has enabled us to see further and with greater clarity than ever before. At the time, the camera that we built was the most sensitive camera on Earth or in Space. And it turned out to be the longest-serving camera in orbit. It was only removed in 2002 after twelve years of operation. It is still a world record. It could measure, for example, the width of a human hair at a distance of one kilometre and it was so sensitive it could have detected a candle at half the distance to the moon.
(space rocket sound effects)
Now after a successful launch in 1990 – there it is going up on the Shuttle – Hubble was deployed from the cargo bay of the Shuttle. There it is with those enormous solar arrays to give it power. And we sat and we waited. Now I don’t have to tell you that Hubble had a few teething problems.
All right. Which bloody fool left the lens cap on!
Well, it wasn't quite like that. It was more a problem with the mirror, beautifully manufactured and figured – to the wrong shape. Nothing to do with me, Guv, honestly! My bit worked perfectly from the start.
So this is obviously an example of where our fingers weren't crossed tightly enough. Now by that time I had moved on to other projects but still I was desperately disappointed that it appeared to have failed. Well, as we know, eventually NASA launched a rescue mission three years later in 1993. They put on a correcting lens in front of the mirror and it worked fabulously. It was really worth the wait. Here, for example, is one of the early images from the Faint Object Camera that I worked on. This is Pluto and its satellite Charon, beautifully resolved as never before. And also, for the first time, we were able to see Pluto and to see some structure rather than just a blur of light. But of course Hubble is best known for some of the beautiful images that it produces, some of the visual images. Let’s have a look at a few of them. This is a spiral galaxy. You can see some of the stars and some of the beautiful structure there. A nebula with different colours representing different elements, different temperatures. The famous Orion Nebula. You can see Orion’s Belt and Sword with the naked eye. This is a region where stars are forming out of gas and dust before our very eyes. And one of the most breathtaking achievements of Hubble was something called the Ultra Deep Field. What Hubble astronomers did was to choose a tiny part of the sky – in fact it was the size of a pinhead held at arm's length – a perfectly anonymous piece of sky and we are homing in on it. And Hubble stared at it for one million seconds to build up an image.
And what did it find? Well, as it stared and built up the image it found that this apparently anonymous piece of sky actually was filled with thousands of galaxies. Each of these is a galaxy and each galaxy contains literally billions of stars. There are some people who believe now, I think with some confidence, that of these stars, maybe as many as ten per cent of them, also possess planetary systems. So I think you can see there the implication is pretty mind-boggling. And there is something else. You know that, when we look at the Sun, we are actually seeing the Sun as it was about eight minutes ago. That’s how long it takes light to reach us. If we look at some of the nearby stars they are light years away so we are seeing them as they were a few years ago. With some of these objects in the Hubble Ultra Deep Field, these are some as far as thirteen billion light years away. So we are seeing them as they were thirteen billion years ago. And, as I am sure as you all know the Universe is merely fourteen billion years old. So we are really looking back with Hubble, far, far back to close to the origin of our Universe. So Hubble really is the closest thing that we have to a time machine. It really does help us to look back in time.
Now my speciality for the last twenty years or so has actually been going to other planets and other objects in the solar system rather than merely, if I might say that, observing from orbit around the Earth. The first such object that I went to was Halley’s Comet – Halley, named after Sir Edmund Halley, the famous astronomer. And this was the destination for
Now, what was Giotto going to do? Well, this is a typical image of a comet from the Earth. We see a head or a coma, as it's called – a bright condensation of light – and the characteristic feature of a comet, which is this tail which spreads thousands, tens of thousands, hundreds of thousands of kilometres across the sky. Gas and dust reflecting light. But what we didn’t know is what's at the heart of it all? What creates this? What causes this? What is at the centre of the cometary coma? We can't tell from the Earth, we are blinded by the light, the scattered light, and we just don't have the resolution, the ability, to peer in there. So the answer was to send a spacecraft to have a look. Now our instrument, the one that I was helping to design and build, was actually to look at the dust – the dust making up much of the structure. And we wanted to measure the size of the dust particles; its mass and also how it was distributed about the comet.
Now there was a problem. The closing speed, the relative speed between the spacecraft and the comet, was sixty-eight kilometres per second. That’s a hundred and fifty thousand miles an hour or from here to the centre of
Anyway, how are we going to collect, with our instrument, our dust impact data? Well this is a cartoon of Giotto travelling through space. And you might be able to see that, at the front of the space craft, there is something called a bumper shield. Here we can see it in more detail. It had never been tried before in space. At the front there was a shield, quite thin, aluminium, a few millimetres thick, that would protect us against the very smallest particles. But the larger ones (large, remember, is thousandths or even less of a gram) would punch straight through and we then had a second shield here made of Kevlar, that’s the material that you make bullet-proof vests out of. The act of going through the front shield would spread the particles out and they’d impact over a wider area and that, we thought, would give us a chance to protect ourselves against all but the worst particles. Here we can see the team working on a flight spare of the front shield and what we did was to put our sensors on the rear side of that front shield. Here you can see some of them. And what these are essentially is very sensitive microphones. Every time a dust particle hit the shield it essentially set up an acoustic wave, a sound – it created a sound and our very sensitive detectors would pick up that sound. We also put some sensors on the rear shield to pick up those ones that punched through the front and got through the rear shield.
(launch sound effects)
Well, the launch was in 1985, summer 1985. Nine month journey to get to Halley's Comet. So I would like you to imagine the scene. We are now March 1986. We are in Mission Control, Europe’s version of
Our predictions had said that we would detect our first dust impact between minus ninety and minus eighty-five minutes. The clock kept on ticking. The minutes passed. Nothing. We were the only one not working. So there we are: the DIDSY team – we were the Dust Impact Detection System – sitting there at our monitors, very, very quiet. We were watching a row of zeros literally passing through our screen. Was DIDSY going to become DUDSY? Had our instrument packed up? Important scientific thoughts were going through my brain – such as, “Where could we hide?” (laughter) “Who was responsible?” “Who could I blame” Then, thank the lucky stars, (ping) the sweetest “1” I had ever seen. It happened at minus seventy-two minutes. We had the first dust impact. It was wonderful. Fingers uncrossed, cheers went up. We were happy too. My goodness were we happy!
But we were still more than a hundred and fifty thousand kilometres away from the target but closing fast. We converted the data into a sound file so you could hear it as if you had been sitting on the front shield of the spacecraft. This is how it would have sounded when we were far out (sound effects) – just the occasional hit on the shield. We moved in. The hits started to build up. Twenty minutes to go and the spacecraft is beginning to take quite a battering. In fact, we now start to get the occasional impact on the rear shield, so bigger particles are beginning to bombard Giotto. Will the shields hold, Scotty? (laughter) We are now only minutes away from the closest approach. Whatever happens, it doesn't matter. It's a success. We have got lots of data. But how close could we get? Moments later and some of the data channels started to saturate, we are getting so many hits. We are within one minute from closest approach. And then – it happened. (silence) We lost everything. Screens go blank. We assumed a big particle – the spacecraft had been lost. But it had exceeded our wildest dreams. Cheers, hugs, the champagne started to flow. The end.
Well was it? No. We hadn’t finished the first glass of champagne before a voice piped up from the other side of the control room. We have still got some data. What’s going on? But there is something strange about it. It wasn't like before. (sound effects) It was coming through in bursts. We were getting a burst of data then a blank, then a burst of data again. What we think happened was that a particle had hit, probably on the very edge of the shield, and it had set the spacecraft nutating – or wobbling. Now the radio transmission back to the earth was in a narrow beam so, with the spacecraft wobbling, this meant that the beam was waving around. So it was literally going backwards and forwards across the Earth and we were just picking up bursts of data. But there was actually an on-board system to damp out the wobbling and, over the next twenty minutes the wobbling gradually died down. And so we had the situation about twenty minutes later that we were actually receding from Halley’s Comet still taking data, which we never imagined could happen. But actually, Giotto was not quite as before. The camera was blind. It wasn't sending any pictures. The temperatures were all over the place and actually fifty per cent of the instruments were dead. But DIDSY was alive, or at least ninety per cent of it was alive. Well, what do you do with a half-working comet-probe? Well, you send it to another comet of course.
But hang on. One small problem. We had virtually no fuel left. Well there is a way around that because in space there is something, we do have something, that is very close to a free lunch and it's called the gravity assist manoeuvre. If you send your spacecraft to fly past a planet or a large body, and if you get everything just right, the geometry,the speed and so on, you can actually use that planet to sling you off in another direction. You can change the course for free. And the clever people who were controlling the Giotto spacecraft realised that the orbit, it was actually an orbit that would bring it back to Earth, about four years later. So in 1990, Giotto flew over the rooftops. About a thousand kilometres. And it was shot off towards another comet – Grigg-Skjellerup – a comet that you will never have heard of – totally anonymous. But that is what we wanted. We wanted to compare it with Halley.
Well, what happened? We got there. At Halley we got about fifteen thousand impacts that we measured. At Grigg-Skjellerup we got three. A lot less active a comet and we were also travelling more slowly, relatively speaking, which meant that we had less sensitivity. Anyway, it was wonderful. We got more scientific papers. European taxpayers got wonderful value for money. (laughter) Giotto survived that too. We built it well. But what to do with it next? Well I actually formally suggested to ESA, because I worked out that we could actually crash it into the moon, not for a bit of fun – well it would have been fun to be honest – but I think we could have got some good science out of it. But that was a step too far for ESA. So it was sadly turned off. And where is it now? Well, it's trogging around the solar system, forgotten by almost everybody but certainly not forgotten by those who worked on it over twenty years ago. Actually I think this mission was very, very important for the European Space Programme. It really put
Well, what other instruments have been dear to my heart? Well, I would like to say something about my involvement in the mission to Mars, led of course by my colleague Colin Pillinger from the OU. It's something that I am very proud of but, as you know, our fingers weren't crossed tightly enough on that occasion. Now of course got as far as being released from orbit around Mars. Everything was functioning well then. But we heard nothing more from it. We don't know what happened but surely some day we’ll find out.
Nevertheless my team built a meteorological station or a weather station to go on . That was our contribution to it. It was to measure temperature, pressure, wind speed – I don’t know if you can see at the top sticking up there – that’s the wind sensor. It would have measured wind speed and wind direction on Mars. We would have measured dust impact and we would also have measured for the first time the ultra violet radiation. And all of that for 160 grams. What was tremendous about was the way that everybody managed to miniaturise their instruments – most of them are shown there – to fit in a very tight space.
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Copyright & revisions
Originally published: Tuesday, 12th June 2007
Last updated on: Tuesday, 26th June 2007
- Body text - Copyright: The Open University
- Audio - Copyrighted: The Open University
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