When did you last use a by that time the Earth has curved away by missions/index.html that same five metres. So it keeps going. satellite? The Hubble Space Telescope orbits at 600 Eventually (after about 92 minutes) it would km, circling the Earth every 96 minutes. It is probably a lot closer than you think. get all the way around the Earth and hit you This allows it to be serviced by the Space Satellites do a lot of jobs, they help us in the back of the neck (if you were stupid Shuttle. talk to one another, they monitor our enough to still be standing there). weather and let us know where we are. We The GPS navigation satellites fly in a use them to map our world and some help Where are they now? number of orbits at 20200 km, each at an to rescue ship wrecked sailors or get aid to angle of 55º to the equator. This means that Satellites fly in different orbits, depending on disaster areas. there are always at least four satellites in the what they do. The International Space Station sky from any point on the ground. orbits at about 340 km above the Earth, at an Orbits Communications satellites fly at an altitude angle of 51.6º, so that the Space Shuttle and of 35845 km above the equator. They take the Russian Soyuz launcher can reach it. You How do satellites stay in orbit? precisely 24 hours to circle the Earth, so can find out where it is now at: Why don’t they fall down? that they appear to hang in a fixed point in http://spaceflight.nasa.gov/realdata/tracking/ They do fall, but they fall around the the sky. Earth. If you drop a stone over a cliff it Envisat, the European Space Agency’s You can sometimes see one of the nearer falls Earth Observation satellite, has an orbit 783 satellites just after sunset, because while km going over the poles, so it gets to see about five metres in the first second. If you are in darkness the satellite can still everywhere on Earth twice a day. ESA has a you throw it horizontally at 7900 metres be in sunlight. Use one of the tracking site tracking all its satellites at: per second (that’s some throw) it still sites to find out when one is going to go falls five metres in the first second, but http://www.esa.int/SPECIALS/Track_ESA_ over you. • Earth Observation satellites like Envisat and Meteosat provide us with accurate data used for weath- er forecasting.

• In the wake of the Tsunami in 2005 satellites provided vital information to emergency services detailing the areas most affected and helped get aid to those areas. • Earth observing satellites are continually monitoring our planet and the recording the changes If you thought GPS was just about SatNav occurring due to global warming, you were mistaken! Look deeper and you’ll this data is used to try and help cut find GPS has many applications… emissions and try to prevent further damage to our planet. • GPS is used to timestamp all transactions made at our cash machines and in our banks • GPS timing is used in telephone networks • GPS is used by Taxi companies not only to help them find the quickest route to a des- tination but also to track them from the call centre such that when someone calls for a taxi the nearest one to the pick up can be sent. And somethings you might not realise initially came from technology developed for use in space… • Lightweight blankets – these “foil” blankets often used by runners at the end of a race and by emergency services were originally developed for protecting satellites in space. • Smoke Detectors – originally developed for use on the Skylab Space Station, they are now found in virtually every home. • Cordless Tools – now used everyday, items like cordless drills were developed for the Apollo astronauts and used during the Moon landings. • Do you have Sky TV at home? The SKY service is broadcast via satellites. The signal is then relayed to your home via the small “sky” dish (receiving antenna) on the side of your house. • All television channels are also broadcast initially via satellites – without the satellites there would be no TV! • Satellite based communications help us to keep in touch with one another wherever we are in the world or in space! All images credited to NASA and ESA

In every issue of Voyage some of your frequently asked questions relating to space and space technology will be asked by our space experts. Send in your questions for our experts and yours might appear here. 1 Which was the first ever satellite in space? The first satellite to be launched was Sputnik 1. Launched on 4 October 1957, Sputnik 1 was built by the Russians. It was the creation of Sergi Korolov. Sputnik remained in orbit for 91 days before Victoria Hodges burning up in the earth’s atmosphere.

2 How many satellites are orbiting the Earth? Astrium Ltd, Stevenage, UK, It is estimated that there are approximately 8000 satellites in orbits Graduate Development Programme. around the Earth.

3 How much does a satellite cost? Different satellites cost different amounts. The large communications I’m a graduate engineer, recruited into the Attitude and Orbit Control satellites that broadcast our TV signals cost around $100 million GPS Systems, Guidance Navigation satellites cost around £150 million whereas scientific satellites like the Control & Flight Dynamics Group Hubble telescope can cost around $2000 million. Stevenage, UK, working on formation 4 How do satellites get into space? flying studies. I spent three months Satellites are put into space by large rockets. These working in Toulouse, France in the rockets usually have stages, the first stage is used at Advanced Studies group (formation the beginning of launch to give the rocket the initial flying) and currently working on the Aeolus project doing Systems boost into space. The second stage is then ignited Engineering and Operations support. and finally the third stage is used to put the satellite In my final year of university I decided into it’s desired orbit. to apply to EADS Astrium, and was taken onto their graduate programme, a two year scheme designed to allow new graduates to experience a wide range of roles within the industry.

Find the words in the word search below Although I always had an interest in describing space in your daily life. space, it wasn’t until I was in my final year at secondary school (aged 15) Z­ W­ I­ B­ V­ S­ N­ E­ P­ L­ that I really thought about a career in B­ K­ E­ O­ E­ L­ I­ L­ A­ G­ the space industry. This was mostly thanks to my physics teacher at the K­ A­ T­ A­ H­ V­ P­ M­ W­ P­ time who encouraged my enthusiasm M­ E­ S­ L­ T­ C­ I­ Y­ K­ S­ for the subject. Not knowing much W­ I­ A­ E­ L­ H­ G­ H­ J­ K­ about engineering, I decided to follow the physics route into space. R­ O­ T­ G­ I­ T­ E­ V­ A­ N­ S­ U­ N­ Q­ P­ O­ K­ R­ I­ A­ Send in your questions to our U­ D­ A­ B­ R­ A­ D­ I­ O­ D­ space experts at: E­ N­ V­ I­ S­ A­ T­ W­ A­ B­ Voyage, Y­ O­ I­ S­ I­ V­ E­ L­ E­ T­ BIS, 27/29 South Lambeth Rd, London, SW8 1SZ SATNAV GALILEO WEATHER Email: [email protected] SKY DAB RADIO TELEVISION Web: www.bis-space.com/education GPS ENVISAT

Edited by Victoria Hodges (Astrium) and Bob Parkinson, Designed by Melanie David-Feveck Published by the British Interplanetary Society. Registered Company No: 402498. Registered Charity No: 250556.