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Another Notable 2017 Space Anniversary: I n this account of the rather incredible (in the true sense of the word) achievements of Cassini and Huygens in September this year it would be remiss of us NOT to mark an even more incredible anniversary also occuring this year – that of the launch of the first manmade Earth satellite, Sputnik 1, by the Soviet Union on October 4, 1957. Arguably the only comparison between Sputnik and Cassini is that they were both launched into space! Where (huge) Cassini has been responsible for virtually continuous transmission of data and pictures since its launch, the tiny Sputnik (a 585mm, 85kg sphere) was capable of “only” transmitting a series of beeps as it orbited the Earth. Thousands of amateur radio operators listened out for the faint signals from Sputnik on 20.005MHz (close to the 21MHz amateur band and well within the capabilities of most amateur equipment using that 22 Silicon Chip band) and 40.002MHz (a VHF signal requiring more specialised receiving equipment). What those thrilling at the sound of those 0.3s pulses didn’t know was that they were also listening to the first data from space: Sputnik’s radio signals from its one watt, 3.5kg transmitter were encoded with (quite elementary!) telemetry data, not only initially telling controllers of the satellite’s successful deployment but during the flight, information on the electron density of the ionosphere along with satellite temperature and pressure. After several unsuccessful test firings of R-7 launch vehicles, Sputnik was carried aloft on an 8K71PS rocket (itself a modified R-7) from Site No.1 at the 5th Tyuratam proving ground in Kazakh SSR (now known as the Baikonur Cosmodrome), at 19:28:34 UTC. The control system of the Sputnik rocket had an intended orbit of 223 by 1,450km, with an orbital period of 101.5 minutes; the actual orbit turned out to be 223 x 950km with an orbit every 96.2 minutes. There are several reasons for this difference – remember that even with the brightest minds in the Soviet Union working on the project, much of the work was theoretical, unproven technology. Not all to plan! Even the launch didn’t go exactly to plan: a booster failed to reach full power at lift-off, causing the rocket to tilt over at 2° just six seconds after liftoff. The booster reached full power just one second before the launch would have been automatically terminated. This would have caused the spacecraft to crash close to the launch pad. Then 16 seconds into the flight, a fuel regulator in the booster also failed, resulting in excessive fuel consumption and 4% higher than expected engine thrust. This resulted in termination of the thrust one second early – hence the siliconchip.com.au 60 Years since Sputnik different orbit than expected. However, at 19.9 seconds after engine cutoff, the second stage separated and the radio transmitter was automatically activated, indicating a successful deployment. Engineers listened to the “beepbeep-beep” for two minutes, until the craft disappeared below the horizon. They waited some 90 minutes until Sputnik was once again in “view” and confirmed radio reception, before calling Soviet premier Nikita Khrushchev. TASS, the Soviet news agency, then announced to the world the successful launch and deployment. Strangely enough (considering the times) it took some time for the Soviets to start making any real propaganda mileage out of Sputnik. But in the USA, the launch was met with some fear and trepidation with the realisation that they had, at least then, lost the lead in the “space race”. Three week life Sputnik had a design battery life of just 14 days – it continued to trans- mit for three weeks until its battery finally gave out. But the craft itself continued to orbit the Earth (where it could often be seen, depending on its height) for another three months, until it re-entered the Earth’s atmosphere and burned up on January 4, 1958, having completed 1,440 orbits. How many Sputniks? While there was only one Sputnik to claim the title of “the first”, there were at least three (and possibly more) duplicates built. One of these, a complete system, is in the “Energia” corporate museum just outside Moscow, where it is viewable by appointment only. Another is in the Museum of Flight in Seattle, Washington – while it has been authenticated (and even shows some signs of wear) it doesn’t have any internal components. And there are said to be at least two other duplicates in private collections. There are dozens of “replica” Sputniks in various museums and collec- tions around the world – one even in Australia at Sydney’s Powerhouse Museum. And there were three studentbuilt one-third scale Sputniks deployed from the Mir space station between 1997 and 1999 (the first launched to mark the fortieth anniversary of the original Sputnik). Yet another “went down with the ship” when Mir burned up on its controlled re-entry on March 23, 2001. SC Image Credit: http://unusualsuspex.deviantart.com/art/Sputnik-1-Tech-Readout-new-470662574 siliconchip.com.au September 2017 23