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 Questions about rockets
 Questions about balloons
 Questions about satellites

 

GENERAL

What does Esrange stand for? Is it a name or an abbreviation? Actually both. When it was started in 1966, the full name of the facility was ESRO Sounding Rocket Launching Range. ESRO stands for European Space Research Organisation. ESRO's facilities all had short names starting with ES, so the rocket range in northern Sweden was called Esrange. Nowadays, Esrange is actually the name of the geographical place and the facility is called Esrange Space Center. Is it a military facility? No. Esrange is a civilian facility, working with the peaceful exploration of space. It is, however, classified as a protected area in the Swedish civil defence, as it houses telecommunications facilities. For how long has Esrange existed? It was built 1964–66, and the first rocket was launched in late 1966. What is Aurora? The sun constantly sends out particles, together with the light we can see. Actually it also sends out light that we cannot see. Some of the particles will be caught by the magnetic field of the Earth, and travel towards the North- and South Pole. As these particles collide with the atmosphere, small flashes of light are emitted. One Aurora can consist of billions of small flashes. The flashes only last for a very short time, but more particles will collide directly afterwards, but not in the same places. This makes the Aurora move and shift as you look at it. The collisions take place around 100 – 250 km above the surface. How many scientists work at Esrange? From 0 to 50, depending on the time. There are no scientists employed by Esrange. Scientists that work at Esrange will come from research institutes and universities from all over the world. They bring their experiments during campaigns, and the technical staff at Esrange launch the experiments with the help of rockets or balloons. Campaigns usually take place during the period September–May, and can be from 2 weeks up to 3 months long. Can I visit the area?  See our page about Public visits How is the Esrange facility paid for? Esrange is the property of the Swedish Space Corporation, a state-owned company under the Ministry of Enterprise, Energy and Communications. A special agreement with ESA, the Esrange-Andöya Special Project, says that Sweden, Germany, France and Switzerland all put a certain amount of money into the scientific rocket and balloon work at Esrange. The Swedish contribution represents around 50%.

ROCKETS

Do you reach space? Yes. Our rockets fly up to 800 km altitude. Space begins at 100 km. A Space Shuttle flies at around 250 km and the Space Station at 400 km. Do you send up people or animals? People no, animals yes. But nothing larger that a sea-urchin has ever been sent up. Quite a few viruses and cells have been flown. When is the next launch ? Better check the Launching Programme. How many launches do you have per year? Normally 5 to 10. We have launched as many as 54 in one year (2003). In 2007 there was no launch at all. How many rockets have you sent up?  Around 500 (as of April 2008). 152 during the time ESRO was in charge and the rest as a part of SSC. What does a rocket consist of? A rocket is made up of at least two parts; the payload and one or more rocket motors. The payload contains all experiments and equipment that makes it possible to see what happens on the rocket. The rocket motor will burn and push itself and the payload upwards. As soon as the motor is empty it is separated from the payload. The payload comes down by parachute, while the rocket motor falls down without a parachute and smashes into the ground at around 300 km/h. What are the rocket motors made from? Steel and composite materials. Inside them is fuel. The fins? Often aluminium, but also steel. What fuel do you use? We use solid fuel, a rubber-like substance, sometimes mixed with aluminium and with ammonium-perchlorate as an oxidizer. Where do the rocket motors come from? From Brazil and the US. Can you steer the rockets? Well, no-one sits with a joystick, flying the rockets. Some of the really high-flying rockets we use are guided by an internal system, so a computer steers them. Most of the rockets, however, are just pointed in the right direction and launched. Are the rockets environmentally friendly? Well ... actually not. As the fuel burns, carbon dioxide and hydrochloric acid (HCl) will be produced, and chloride compounds are released into the stratosphere. On the whole, we are talking about negligible amounts compared to the world's all emissions, but still, it is regrettable. Nevertheless, at this point, it is necessary if we are to send up sounding rockets to make measurements and perform important research. Hopefully there can be a shift towards more environmentally friendly liquid fuels when newer rockets come into production. How many rocket launchers are there at Esrange?  5 in all. 3 permanent (stationary) and 2 mobile. How much does a rocket cost? A complete rocket, with experiments and all is hard to estimate, since experiments can vary a lot in costs. The latest Maxus cost around 100 million SEK, of which the rocket motor cost 10 million SEK. A medium sized research rocket might be launched for 15 million SEK in all. Can I come and watch a rocket launch? Normally, no. For safety reasons, we try to have as few people as possible in the area when we launch rockets.  Sometimes there are special occasions when VIPs can watch the launches from special places at Esrange. In March 1998 a 5th grade school class were VIPs, since they had built an experiment for a rocket. How do you find the rocket afterwards? Usually we want to find the payload first, since it contains the experiments. The payload is tracked by radar and radio receivers so we know approximately were it is. In the payload part of the rocket there are, together with the experiments, systems with GPS and radio transmitters that transmit the position of the payload so you can find it. There is also a radio-beacon ( a here-I-am signal ) on the payload so it can be found even if the other system fails. A helicopter then flies to the place and fetches the payload. The rocket motor is just junk, since it falls down without a parachute and smashes into the ground at around 300 km/h. Normally it is buried in deep snow, so it cannot be seen. When people go into the impact area during summer and autumn, they can find the motors sticking up from the ground. They call us, get a small reward for finding it, and we fetch the motor. Can the rocket fly in a direction it is not supposed to? Yes. If a rocket system error occurs, or the wind changes the rocket's direction at start, the rocket might miss its intended impact point. That is one of the reasons for placing Esrange in the northern part of Sweden. There are no people living permanently in the area where the rockets fall. If a guided rocket suffers a computer error, we could loose control over the rocket, which could be really bad. The Castor 4B motor can fly 2000 km if the computer points the rocket at a 45 degree angle. This means that all the Scandinavian capitals could get hit. The guided rockets can therefore be destroyed before that happens. An unguided rocket can normally fly only a little bit away from its intended impact point, since the wind cannot redirect it more than a couple of degrees. For how long does a rocket fly? The largest rockets we launch are aloft just over 20 minutes, a middle-sized rocket around 10 minutes. What kind of experiments are launched? The early flights normally studied the Aurora (the northern lights) or the atmosphere. Such rockets are still flown, but most of the experiments are intended to study physical, chemical and biological processes in microgravity (near weightlessness). The processes are easier to study when the effect of gravity is eliminated. What countries come here to make research on rockets? Anyone can come, but most scientist come from European countries. German and French scientists are the most frequent.  Where do the rockets come down? They come down in the Esrange Impact Area. This is a large uninhabited diamond shaped area north of Esrange, 120 km long and 75 km wide. The reason for the large area is that the wind and irregularities in the motor can cause the rocket to miss the target point. We aim at a point in the middle, 60 km from Esrange. If everything goes as planned the rocket impacts within a couple of km of the target point. Is the Esrange impact area fenced? No. Anyone can enter most of the area at any time. It is an excellent area for fishing, hunting or outdoor activities, so people are often there. You are not allowed to build any permanent dwellings there, since they might get hit by falling rockets. Before a launch, we inform the public to make sure no-one visits the area at the time of the launch. We also survey the impact area by helicopter before launch. Are rockets launched all the year around? If the scientists want to, yes. Normally they prefer to launch during winter, when there is ice and snow on all the lakes in the Impact Area. The payloads could otherwise be lost in a open lake. What happens with the rockets afterwards? The payload is often re-used. There is one experiment that has flown 7 times. The motor is put on the "rocket graveyard", since it is just a piece of junk. What kind of education do you need to work as a rocket technician? The educations are different, but all personnel that work with rocket launches at Esrange have a technical background, for example Space Engineers.

BALLOONS

How high can a balloon fly? The balloons Esrange launch normally fly at 30 - 35 km altitude, but they can reach altitudes up to 45 km. It is very hard to fly balloons higher than that, due to the fact that there simply is not enough air left to lift it much higher. For how long does a balloon fly? Normally 2 – 5 hours. There have been flights that lasted 22 days, circling the North Pole five times. What are the balloons filled with? Hydrogen or helium. Due to the explosive nature of hydrogen, really big balloons are filled with helium. Helium is, however, not as efficient as hydrogen, and much more expensive. Which countries do the scientists come from? Most come from European countries, but also from the US, Russia and Japan. How do the balloons fly? If a balloon is launched during the period September-May, it will fly eastwards due to the prevailing winds. If it is launched in summer the winds will take it out over the Atlantic. During late May and during August, the winds turn from east to west (or the opposite way) which means that a balloon launched during these periods will more or less stay stationary over Esrange. During this "turn-around period", balloons can fly for 2 days and still land near Esrange. Do you have to land in the impact area? No. The balloons are not dangerous, as nothing heavy falls down, like the rocket motor. That means that we can land almost anywhere. We often land in the east part of Sweden, in Finland or in Russia. We have flown a balloon as far south as Dalarna, a region in the middle of Sweden, north-west of Stockholm. NASA has flown balloons from Esrange to Canada. Can you steer a balloon? Well, up to a point. Balloons fly with the wind. If the wind blows the way you want to go, everything is fine. Since the winds blow differently at different heights, the balloons can be steered by changing altitudes. By releasing gas you make it sink, and by dropping ballast you make it rise.

SATELLITES

What is a satellite? A satellite is a body that orbits another body. That means that the Moon is a satellite to the Earth, just as the Earth itself is a satellite to the Sun. When people talk about satellites, they normally mean the man-made objects that circles the earth providing services such as television or accurate weather forecasts. Which was the first satellite of the Earth? Well, from the definition above; the Moon! The first man-made satellite however, was the Russian satellite Sputnik 1, launched October 4, 1957. How many satellites are there? Ouch ! That’s a tricky question. There are quite a lot of satellites, since everything that orbits the Earth by definition is a satellite. Every little thing that is dropped by an astronaut will be a satellite. A Hasselblad camera that was dropped during a space-walk in the 60’s is regularly called the first Swedish satellite. There are around 2000 satellites that orbit the Earth, of which about 500 are still in use. There are a lot of discarded objects in space that, by definition, are also satellites. There are around 9000 pieces that are larger than 10 cm, and 150,000 that are bigger than 1 cm. Some of them can be very dangerous for an astronaut, a Space Shuttle, a Space Station or a working satellite. What orbit does a satellite fly in? That depends on the satellite's purpose. Satellite orbits are normally either polar or equatorial. A polar orbit goes, as the name suggests, over the poles. An equatorial orbit goes over the equator. There are also orbits that are tilted so they fly somewhere in between. The orbit could either be circular or elliptical. An elliptical orbit will take the satellite to different altitudes, while a circular orbit will keep the satellite at a specific altitude all the time. Altitude also differs depending on the mission. It takes more time to orbit the Earth if you are at a higher altitude. At 850 km altitude one orbit takes around 100 minutes, while it at 36 000 km takes 24 hours. You also see more or less of the Earth depending on the altitude. If you fly on a Space Shuttle at 250 km, the area of the Earth you will see is around 3000 km across. If you fly at the altitude of a Remote Sensing Satellite (850 km up) the area is around 6000 km across and a telecommunication satellite will see the whole side of the Earth that it is above, as it is flying at 36 000 km altitude. Remote sensing satellites are put in polar orbits at around 800 – 900 km altitude. Since the Earth spins the satellite will fly over new areas on every orbit. It will always fly over the poles but eventually it will also have flown over all parts of the Equator. Telecommunications satellites are put in an equatorial orbit at approx. 36 000 km altitude. At that altitude it will take 24 hours to orbit. Since the Earth takes 24 hours to spin one revolution, the satellite will seem to stand still in the sky. It is easy to point your antenna towards it and get signals. How do you contact a specific satellite? Each satellite uses a specified radio frequency for receiving commands and to send data to the Earth. Since several satellites can use the same frequency, the transmissions are normally coded. If the satellite does not recognise a specific sequence at the beginning of the control signal, it simply ignores it. It is possible to listen to signals from satellites, even spy satellites, but it is hard to understand them. Some satellites do send free information, so the only thing you need is a radio with antenna in the right frequency, a computer and a program. Amateur radio clubs might help you. How big are the satellite antennas at Esrange and what type are they? The satellite antennas that are at Esrange are parabolic dishes ranging from 3 to 13 metres. What can a remote sensing satellite see? The satellites that we work with can see objects as small as 10 x10 metres, in some cases even smaller. They can look in different wavelengths (colours) which means that different vegetation can be discerned. A wheat-field looks quite different than a corn-field, if you look at it in a specific colour. How small things can you see with a satellite? The best civilian satellites that are under development right now will be able to see things as small as 0,5 metre. Such small objects will just be dots on the computer screen, though, so you cannot say if it is a stone, a concrete block or a gravel pit. But you can see that there is something there. The best military spy satellites can see even smaller objects - less than 10 cm for the best sensors, with 1-2 cm as the optimum according to rumors. Are satellites launched from Esrange? No. Esrange has no capability to launch satellites at present.