Telstar-1 at 50
What part did Telstar-1 really play in the history of communications satellites?
‘Goonhilly Ariel 1’ possessed a 26-m diameter antenna weighing 870 tonnes, rotating on a turntable
Goonhilly earth station in the 1960's
Telstar-1 was the first private-sector space mission, entirely financed by US telephone monopoly AT&T
In the summer of 1962 Telstar-1 helped ignite the white heat of technology that burned throughout the rest of the decade. Fifty years on, how well deserved is its reputation as a global comms game changer?
A media star in its own right, the first Telstar had something special. Half a century ago, on 10 July 1962, that 88cm-diameter sphere relayed the first instantaneous television and telephone signals across the Atlantic – and promptly became an icon. Millions of Britons viewed its shaky first pictures. "The invisible focus of a million eyes" became the Queen's description in her next Christmas Day address.
For the public, the Telstar experiment showed that Space could be useful, single-handedly kick-starting the multi- billion pound satellite telecommunications industry – up to a point, at least, for the historical truth is somewhat more nuanced, for arguably Telstar-1 was both a great leap forward – and a technological cul-de-sac.
Nasa actually had little to do with Telstar-1 (or Telstar-2) other than receiving $6m for launch services, and claiming patent rights over mission discoveries. Telstar-1 was the first private-sector space mission, entirely financed by US telephone monopoly AT&T, and designed by its renowned research arm Bell Telephone Laboratories. An experimental prototype, it was also a solid commercial investment – planned as the first step in an ambitious 'Telstar belt' to rapidly connect the world; this vision was not to be, as much for political reasons as technical.
Telstar's father was John R Pierce, head of Bell Labs' communication division (and a science fiction author). On 4 October 1957 Sputnik-1 brought these pursuits together. "It's like a writer of detective stories going home and finding a body in his living room," Pierce remarked later. "Space had suddenly changed from science fiction to a technology that could be put to some sensible use."
Pierce calculated the same microwave technology linking telephone towers could bounce off a satellite – given a sufficiently powerful amplifier. The Second World War had introduced just such a device. Austrian émigré Rudolf Kompfner worked for the British Admiralty at Birmingham University, where he invented the low-noise, high-bandwidth, high-gain 'travelling wave tube' amplifier, applying electron beams to boost microwave signals. Pierce rapidly grasped its potential, and in 1951 recruited Kompfner to Bell Labs. Now Pierce and Kompfner set their sights on space.
Arthur C Clarke had made the case for geostationary communications in 1945, but 15 years later it still seemed decades away. No available rocket could reach the 36,000km equatorial belt where a satellite remains fixed relative to Earth. Alternatives ranged from late 1950s 'Moon bounce' experiments to 1958's SCORE, the first, 12-day-lifetime communications satellite – re-broadcasting taped messages. The US Air Force settled on flying millions of tiny copper needles into medium orbit through Project West Forda failed deployment in October 1961 was followed by success in May 1963. And in 1960 Pierce and Kompfner worked with Nasa on the Echo-1 mission – a 30.5m-diameter orbital balloon served as a cross-continental reflector. It proved the concept – but the team concluded television relay would require a 300m-diameter balloon.
The first trans-Atlantic telephone cable TAT-1, laid down by AT&T and the UK Post Office in 1956 possessed only 36 telephone channels. An active relay satellite, transmitting either television or hundreds of telephone channels, therefore represented a hugely lucrative bandwidth boost.
Bell Labs accordingly developed Telstar independently, lacking a government contract. In 1961 Pierce declared AT&T was willing to spend $500m (about $3.6bn in 2012 terms) on a Telstar system of "between 50 and 120 simple active satellites in orbits about 7,000 miles high", covering most of Earth.
AT&T was no ordinary company in 1962. A descendant of Alexander Graham Bell's original 1876 firm, AT&T – overseeing the so-called 'the Bell System' – operated 80 million US telephones, had almost a million employees. Bell Labs itself was a technology powerhouse, lately devising the transistor and solar cell – both Telstar essentials. The initial 77kg satellite itself was studded with 3,600 solar cells, coated with radiation-resistant sapphires, producing just 14W. Its internal electronics – including its travelling wave tube - were sealed within a canister suspended inside its shell by nylon cords. 'Spin-stabilised', Telstar rotated at 200 revolutions per minute. Six Telstars were constructed, though only two flew.
More sats please – we're British
Placed into an elliptical 954km by 5,638km orbit on 10 July 1962 (delayed two weeks by a loose wire) Telsta transmitted a mere 2W – or a millionth of a millionth of a watt to Earth; and it was only visible for an average 20 minutes per two-and-a-half hour orbit – and then only when tracked. Sophisticated 'earth stations' had to compensate Bell Labs' Andover in Maine linked to Pleumeur-Bodou in north west France, along with the Post Office Engineering Department's Goonhilly Down facility on the Lizard peninsula in Cornwall. Alton Dickieson of Bell Labs (famously devising the mobile phone in 1946) later mentioned his surprise that the Post Office already possessed a Space Communications Systems branch"The British had been doing quite a bit of thinking on satellite communication'. They were waiting for someone to put up a satellite... The French agreed as soon as they heard the British were coming in!"
The French purchased a replica of the Andover station: a horn-shaped antenna housed in a 64m-high inflatable radome. The Post Office preferred home-made. It selected the Lizard in Cornwall for its ground station, close to where Guglielmo Marconi made the first trans-Atlantic radio transmissions in 1901, for much the same reason: a clear westward view. But Bell Labs' balloon-like radome would not survive Cornwall's Atlantic winds. Instead the Post Office went with an open parabolic design, a scaled-down version of Jodrell Bank built by the same architect. Nevertheless, 'Goonhilly Ariel 1' possessed a 26m-diameter antenna weighing 870 tonnes. It rotated on a turntable manoeuvred by what the press called a bicycle chain, controlled by computer punch tape based on Nasa orbital calculation.
Its single most essential technology involved was a supercooled maser directly behind the dish. The Post Office proudly boosted that every component in Goonhilly was British-made (a US klystron valve was added for Nasa's subsequent Relay satellite testing). Going it alone brought consequences howeveron that famous first night on 10 July the French received perfect pictures while British TV viewers saw ghost-like vertical tumbles, commentator Raymond Baxter declaring unconvincingly"There, clear as a bell!" Miscommunication meant a polarisation filter was fitted the wrong way round – corrected the next day.
A dizzying succession of firsts followed two-way telephony, fax transmission, colour television and white-noise simulation of 600 one-way telephone conversations. Less heralded were the first synchronised timings via satellite, bringing the US Naval Observatory and UK National Physical Laboratory to within one microsecond of each other, and the first satellite data transmissions, exchanging audio-converted bits between IBM computers in Endicott, New York, and La Gaude, France.
What goes up...
Beyond the hurrahs Telstar-1's days turned out to be numbered. It had launched one day after a US high-altitude nuclear test, but radioactive particles persisted along magnetic field lines, exposing the satellite to a hundred times higher radiation than planned. Telstar-1 gradually lost performance, its mission ending in February 1963. Telstar-2 replaced it in May 1963 (to be switched off two years later).
Even as Telstar-1 flew, plans for a full-fledged Telstar constellation had faded. The incoming Kennedy Administration had no wish to extend AT&T's terrestrial monopoly to orbit. The Communications Satellites Act, introduced in spring 1962 and signed that August established the new Communication Satellites Corporation (Comsat) would commercialise future US communication satellites. "The Bell System was legislated out of the satellite business," Pierce complained. To continue working with satellites Telstar's inventor had to leave Bell Labs – but chose to stay. Dying in 2002, Pierce outlived the Bell System – the monolith being finally fragmented by anti-trust legislation in the early 1980s.
Telstar also, alas, orbited on the wrong side of technological history. In 1963 Nasa launched a Hughes-built satellite called Syncom-2. It was even lighter than Telstar, attaining a 36,000km altitude. It adopted a drifting geosynchronous rather than true geostationary orbit, but the writing was on the wall for lower-orbiting communication satellites. The next Syncom-3 managed geostationary orbit, followed by Comsat's Early Bird in 1965. The two Telstars will remain in orbit for hundreds of years (the brand-name remains active, with Telstar-18 launched in 2004). Travelling wave tubes remain vital for comsats, while masers are still employed for deep space communications. The 'Telstar belt' concept of low-orbiting satellites became briefly fashionable again for 1990s mobile telephony – though the resulting 66-satellite Iridium network was only saved from financial ruin by the Pentagon (now backing the forthcoming Iridium NEXT second generation).
In the UK, Goonhilly's parabolic dish set the standard for ground stations worldwide, while in the 1990s the site grew to be the largest satellite earth station worldwide, with more than 60 dishes. Its first antenna – renamed 'Arthur' – was made a Grade 2 listed building. Since the 1980s most telephone traffic switched to broadband submarine fibre optic cables however, and in 2008 BT announced Goonhilly's closure. But three years later a new company, Goonhilly Earth Station Ltd, announced plans to convert the site into a science centre.
Furthermore, Arthur's Telstar-driven manoeuvrability – rendered redundant as immobile geostationary satellites became the order of the day – will once again be routinely employed, to pinpoint tiny objects deep in Space.
Satellite station achievements remembered
IET members John Walling and David Paxman worked together on designing and installing Goonhilly's essential maser amplifier. The maser was the most sensitive – lowest noise – microwave amplifier ever designed, using synthetic ruby as a wave guide, and operated in a high magnetic field at just 2' above absolute zero. John received an MBE for leading the maser team, while David, just graduated from Cambridge, researched maser material properties, later moving to installing and testing it.
John Walling: "I was at Goonhilly on 11 July 1962 when the pictures came through properly. I'd watched the BBC keenly the night before, but it clearly wasn't working well. Raymond Baxter sounded concerned. I was anxious there was something wrong with the maser so I felt I had to go and find out. A maser was always essential because the satellite signal was so tiny – it needed amplification 600- to 1,000-fold. Our workplace Mullard Research Laboratories in Redhill in Surrey was the only site in Europe constructing masers. We were given the assignment in September 1961. It had to be ready by end of April 1962 – in the event we installed it in June. Goonhilly was a building site, with everyone taking turns to test their bits. Everything had to work together properly, but our bit really had to work. It was attached right behind the aerial in a cabin to avoid any loss of gain. The aerial tilted at up to 45' and the maser tilted with it, 50ft in the air. You couldn't be inside the moving cabin, you had to wait below and hope for the best.
"The device could only work at liquid helium temperatures, so we had regular deliveries of liquid helium from the British Oxygen Company (BOC) via British Rail and Post Office vans. Later the Mullard Lab designed larger Dewar vessels for longer operating times. When I made it back to Goonhilly on 11 July a colleague met me at the station, and gave me the good news [that] it wasn't the maser after all! I stayed the evening, hearing Raymond Baxter talk."
David Paxman: "I'd just graduated when I joined the maser team and soon realised an awful lot of important things depended on us making this work. The maser involved various technical challenges: we needed just the right amplitude at just the right frequency. It was as much mechanical as electrical engineering because we had to keep the maser aligned. It was later the significance really dawned, that Telstar was the seed of [today's] global telephone and communications network."
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