18 December 2019
Humanity has always been fascinated by the infinite expanse of space and its stars. The theoretical basis for trips into space, however, was only provided by rocket science from the 1920s onwards, and it was the competition between the superpowers in the Cold War which provided the necessary fuel. If you want to know how space flight is developing, what has changed since the moon landing, and how scientists ensure that probes reach their destination after a journey of billions of kilometres, then read on in our brief history of space travel.
As soon as night falls on Earth, all eyes have trained themselves on the heavens since time immemorial. Our ancestors revered the enigmatic stars as astral deities and began in their astronomical observations to make the first tentative sense of the laws of the heavens and their objects. The possibility of travelling to far-off worlds also occupied the minds of people back in the Ancient World. In “A True Story” written by Roman satirist Lucian around 200 AD, a sailing ship is carried up by the wind to the moon – where its crew becomes embroiled in an interplanetary war between the Moon King and the Sun Ruler. Some 1,400 years later, the astronomer and natural philosopher Johannes Kepler chooses the imaginative framework of a fictional lunar journey to promote the scientific truth of the Copernican empire: In his story “Somnium” from 1608, the father of astrophysics describes what the Earth must look like from the moon. It is clear to Kepler even at this early stage in the science that overcoming earthly gravity will require tremendous force – which is duly provided in his narrative by some helpful demons. The first attempts to set out the technological basis for space travel are made in the 19th century. In his 1865 novel “From the Earth to the Moon”, Jules Verne catapults two Americans, a Frenchman, two dogs and various chickens into space. The space capsule for the interplanetary tour group is fired from a 300-meter super-cannon loaded with 200 tons of explosives. Just like the astronauts of the Apollo missions some 100 years later, the astronauts take off from Florida and use chemical processes to renew their oxygen supply during on the flight. And as with real space projects, huge sums of money must first be raised and various experiments and test flights carried out before the launch can take place.
Rockets instead of cannon
Verne’s vision strikes a chord in the century of the dawn of industrialisation with its infatuation with technology. This should hardly come as a surprise: As the white parts of the map of the Earth continue to melt, our boundless curiosity and desire to discover have led homo sapiens to set its sights on new extra-terrestrial goals – which technological progress will surely allow us one day to achieve.
This, at any rate, is the firm belief of Hermann Oberth. Born in Transylvania in 1894, he devours Vernes “From the Earth to the Moon” as an eleven-year-old. Oberth soon works out for himself that a cannon will not be suitable to transport humans to the moon: the travellers would not survive the gravitational pressure exerted by the enormous acceleration. His alternative solution is a machine that generates its own propulsive forces in accordance with the recoil principle – in short, the rocket.
A rocket starts comparatively slowly and accelerates to top speed only at the edge of the atmosphere. This spares the crew and reduces the friction that slows the spacecraft down. Like the Russian Konstantin Tsiolkovsky (1857-1935) a few years earlier – who, like Oberth, was a passionate Jules Verne fan – he formulates the “ideal rocket equation”, thereby playing his part in laying the scientific and technical foundations of space travel.
Independently of each other, the two pioneers of space travel also develop the principle of the multi-stage rocket: During the flight, the rocket quickly gets lighter as it consumes its heavy fuel, which allows it to fly faster and faster. Once a stage has burned out, the empty shell is jettisoned to further reduce the weight – only in this way can the speeds of 28,000 kilometres per hour that are required to overcome the Earth's gravitational pull be reached. The space capsule itself is just the tiny “tip of the iceberg” on the rocket, which is made up of 90 percent fuel, 9 percent rocket body and only 1 percent payload.
Oberth's 1923 book “The Rocket into Planetary Space” summarises the basics of rocket science and makes them comprehensible to a wide audience. The first liquid-fuel rocket, however, is ignited by Robert Hutchings Goddard in Massachusetts in 1926. Oberth’s first rocket engine for liquid fuel does not fire up until three years later. Young engineers and other rocket enthusiasts, including the student Wernher von Braun, help him with his further experimental work on the conical nozzle.
The latter will go on to become technical director of the first rocket testing centre in Berlin-Kummersdorf, which later relocates to Peenemünde. The “Aggregat 4” is developed here under his supervision in the years after 1939. Under the name “V2”, the world's first functional liquid-fuel missile is intended to secure victory for Nazi Germany as a “miracle weapon”. After the defeat of Germany, the US takes possession of various missiles, construction plans and the expertise of Wernher von Braun and other German rocket scientists. The Soviets must depart largely empty-handed – and yet, it is by the Soviet Union that the Space Age is officially launched only ten years later in what is now Kazakhstan.
The “Sputnik” shock
In October 1957, the whole world is astonished to hear a series of faint beeps from space – and the US is plunged into a state of shock. These are being transmitted by the “Sputnik” satellite, which the Soviets have just launched into space on a rocket of the same name. Just 58 centimetres in diameter and weighing only 84 kilogrammes, the spherical satellite nonetheless has an enormous impact on the United States: its assumed predominance in space and military security in the Cold War back on Earth now seem to be under critical threat from Russian missiles. And the Russians will go on to flex their technological muscles once again in the following month.
© NASAA replica of Sputnik 1 showcased at National Air and Space Museum in Washington D.C.
To find out whether living beings can withstand weightlessness, the Soviets send a mongrel bitch by the name of Laika into space on 3 November 1957. Laika is the first living creature to orbit the Earth but dies of stress and overheating a few hours after take-off. The US founds the National Aeronautics and Space Administration, better known by the acronym “NASA”, in 1958 and begins its own animal experiments to launch its “Mercury” programme. In 1959, it uses a Redstone rocket to shoot Rhesus monkey Sam up to the suborbital edge of space. In other words, the rocket doesn't make it into orbit – but Sam survives the landing. The aim of the “Mercury” programme, named after the Roman messenger of the gods, is to take the first astronaut into space. But here, too, the Soviets pip the Americans to the post.
Yuri Gagarin, the first man in space
On 12 April 1961, army officer Yuri Gagarin is launched into orbit in “Vostok 1” from the Baikonur Space Station. Statistically speaking, his chances of survival are less than 50 percent, according to Russian rocket scientists. But against the odds, the mission succeeds: Gagarin takes 106 minutes to orbit the globe once in his spherical space capsule and lands safely near the south-western Russian city of Saratov, having become the first man in space. A milestone in the early stages of the history of space travel – and a significant victory over the archenemy from across the Atlantic in the first leg of the race into space.
© Finnish Museum of PhotographyJuri Gagarin in a press conference in Finland.
Ten months later, on 20 February 1962, the United States manages to catch up with the Soviet Union with her first manned orbital flight in the “Mercury Atlas 6”, although the Russians are still ahead in terms of the number and duration of space missions.
Kennedy and the moon mission
It is the idea of US President John F. Kennedy that one spectacular success will make up for all the previous defeats in the space race. Only six weeks after the Soviet Union's Gagarin coup, the president announces to Congress that he expects an American astronaut to land on the moon and return safely to Earth before the decade is out. "No other space project will impress humanity more or be more important for the exploration of space,” the president says, at the same time committing the American public to an race against the Soviets whose duration and cost will be without precedent.
In 1965, with the participation of Wernher von Braun, the “Gemini” project, the intention behind which is to prepare for the flights of the “Apollo” missions to the moon, is launched. At its peak, “Apollo” will consume 4 percent of the national budget – with 400,000 people working directly or indirectly on the lunar mission.
A spacewalk is not a walk in the park
Before the first successes are recorded, however, the USSR notches up a few more prestigious firsts: In 1963, the Soviet Union sends the first woman into space. On a journey lasting almost three days, Valentina Tereshkova orbits the Earth 48 times aboard “Vostok 6”. For almost 20 years she remains the only woman in space – and is still the only female astronaut in the history of space flight to have made the trip solo.
In October 1964, the Soviet Union launches three cosmonauts at once into space for the first time in the “Voshod” space capsule. In the “Voshod” mission the following year, Alexei Leonov became the first person to step out of a spacecraft into space. He spends twelve minutes and nine seconds out in space on the end of a five-metre safety cable. But the re-entry is a nail-biting affair: Leonov's spacesuit has expanded so that the cosmonaut no longer fits through the airlock. At the risk of running out of oxygen, he releases some of the pressure and, with a herculean effort, pushes himself back into the airlock. It is not until the Gorbachev era that this brush with death at the end of the first spacewalk is made public.
“Gemini 7” - two weeks in space
In 1965 and 1966, the United States carries out a total of ten space flights under the “Gemini” programme, during which the techniques which will be important for lunar flight are developed and tested. The crews gain experience in handling the craft’s computerised controls, performing docking manoeuvres and working outside the spacecraft. With “Gemini 7”, NASA sets a new endurance record for space flight: Frank Borman and Jim Lovell spend almost 14 days in space, conducting various experiments and proving that astronauts can remain subject to microgravity without medical problems for longer than is required for a lunar flight.
In 1966, NASA launches the final and decisive phase of its journey to the moon with the “Apollo” programme. This begins with an unimaginable catastrophe: on 27 January 1967, the three astronauts in the command module burn to death during preparations for the “Apollo 1” mission. Even so, there is no question of vacating the field to allow the Soviets to reach the moon first. Unmanned missions go on to test the massive “Saturn V” launcher and the lunar module. In October 1968, “Apollo 7” is NASA's next manned space mission and sets off into space in a fundamentally reworked second-generation “Apollo” spacecraft.
© NASAThe crew of Apollo 1 during a training in a simulator. From left to right: Roger Chaffee, Ed White, Roger Grissom.
Final flights before the moon landing
Two months later, on 21 December, a team of astronauts sets out in “Apollo 8” for the first manned flight into lunar orbit. James Lovell, Frank Borman and William Anders orbit the moon ten times, test the lunar module and become the first humans to see the dark side of the moon with their own eyes. The first grainy black-and-white photos of the dark side of the Earth's satellite had already been sent to Earth by the Russian probe “Lunik 3” in October 1959.
© ESA / NASAEarth captured by ESA-astronaut Luca Parmitano from ISS.
But it is the snapshot taken by astronaut Anders on 24 December that will fundamentally change our view of the Earth: In the foreground is the bare grey lunar landscape, in the background the “rising” Earth: blue, white and fragile in the pitch blackness of space. For historian Robert Poole, “Earthrise” marks the birth of the environmental movement. Time Magazine includes the image in its selection of the 100 most influential photographs in history.
Giant leaps in the Sea of Tranquillity
A seminal chapter in the history of space travel will be written the following year. On 16 July 1969, Neil Armstrong, Michael Collins and Edwin “Buzz” Aldrin take off for the moon, going into orbit around the satellite after three days and nearly 400,000 kilometres. On 20 July, they are finally ready: Collins holds the fort in orbit in the “Columbia” command module. Armstrong and Aldrin land in the Sea of Tranquillity in the “Eagle” lunar module. It is Armstrong who first makes his giant leap for mankind, followed onto the lunar surface 20 minutes later by Aldrin.
600 million people watch from their living rooms on Earth as the two astronauts spend two and a half hours on the lunar surface, conducting experiments, planting the American flag in the dust and collecting 21 kilogrammes of lunar rock. Ten more American astronauts will follow Armstrong and Aldrin before the “Apollo” programme is discontinued. On 14 December 1972, Eugene Cernan becomes the last crew member of “Apollo 17” to board the lunar module. He is the last human being to set foot on the moon to date.
Where the race leads, science follows
With the end of the costly “Apollo” programme, the enormous budgets of the space agencies in the US and the Soviet Union are also drastically cut back. Where the race to the moon was above all a question of honour in the battle of the systems, the attention now shifts increasingly to expanding human knowledge of the cosmos: for example, with spacecraft such as the “Pioneer 10”, which sets off for gas giant Jupiter in March 1972. On board is an interstellar “message in a bottle” in the form of a gilded plaque. The intention is to show extra-terrestrial intelligences what we look like and where to find us in the solar system. The probe measures the strength of solar storms, crosses the asteroid belt on the far side of Mars, and reaches Jupiter's system in November 1973. Its nominal mission time is set at 21 months. But the “Pioneer” is more robust than was thought and will become the first man-made flying object in our solar system to send signals for 31 years.
© Getty ImagesSince 1971, space stations are a common feature in outer space.
The USSR quietly ditches its manned lunar programme in the early 1970s after various setbacks. It is more successful with its unmanned lunar flights. For example, in 1971, the Soviets succeed in dropping the first ever remote-controlled rover, the “Lunochod 1”, on a foreign celestial body. At the same time, the USSR has also launched a new programme: The new vision is one of “living and researching in space”. The idea is to construct a space station in orbit around the Earth.
Researching in orbit - Russian space stations and US space shuttles
In 1971, “Soyuz 10” launches the “Saljut 1” station into space. At 16 metres long and weighing 19 tons, it, like its successors, is designed from the outset for a limited service life. In the coming years, the Soviets will amass experience with the aid of a total of seven generations of temporary space stations. On 26 August 1978, East German army officer Sigmund Jähn becomes the first German to go into space, paying the “Saljut 6” a visit that lasts about eight days.
The US is also looking to conduct research in space. To this end, she develops the space shuttles – reusable shuttles designed to make flight into orbit more affordable than the earlier disposable rockets. Compared to the lunar rockets, they have a much smaller range. But, on the positive side they can transport up to eight astronauts and about 24 tons of payload into low orbit to release probes or collect satellites and take them back to Earth.
The European Space Agency (ESA), founded in 1975, also gets involved in the programme for the first time. The European Space Agency provides research astronauts and develops the “Spacelab” for the space shuttle. On his maiden flight in November 1983, physicist Ulf Merbold became the first ESA astronaut to crew a shuttle. The second German in space also symbolises the changing of the guard in space: until now, astronauts and cosmonauts have been recruited primarily from a pool of experienced test pilots. In addition to stress resistance and flying expertise, there is now also a need for scientific skills if you want to book your seat into space.
Cooperation instead of competition - the International Space Station (ISS)
For the first time, the political thaw at the tail end of the Cold War also allows cooperation across system boundaries: In 1988, French astronaut Jean-Loup Chrétien spends three weeks on the Russian space station “Mir”. Following the fall of the Iron Curtain, ESA starts playing a larger part in the Russian space programme. In 1994, Ulf Merbold spends a month doing research on “Mir”. In 1995, astronaut Thomas Reiter spends six months on the Russian space station, with which US space shuttles are now docking more regularly. Two years before Reiter’s stay, the US and Russia are already laying their first plans for a joint space station. By 1998, 13 other countries will join the project – Canada, Japan and 11 European countries. In November 1998, the first component for the International Space Station (ISS) is launched into space, and the station is expanded year on year.
© NASAThe ISS orbits earth at an altitude of 400 km. One orbit around the earth takes 92 minutes.
Material and modules are mainly transported by American space shuttles. Although the reusable spacecraft has proved considerably more expensive than originally planned, NASA's workhorse can once again play to its strengths – until the space shuttles are retired in 2011 for cost and safety reasons.
Electronics for space flights
Someone now has to ensure that the wide range of electronic devices on board the ISS function reliably even after decades under extra-terrestrial conditions - and it is Alter Technology which steps forward. The TÜV NORD subsidiary was founded in 1986. Before long, the expertise of its safety experts is being actively sought for most scientific earth-observation and manned space missions across Europe and around the world. They are involved, for example, with the “Envisat” weather satellite – the largest satellite ever built in Europe –, with the construction of the European “Meteosat” weather satellite system and with the Planck and Herschel space telescopes which furnish researchers with new insights into the formation of stars in distant galaxies and about our own solar system between 2009 and 2013. The specialists are also involved in the mission around the “Curiosity” Mars rover, which has been searching for traces of life for NASA on the Red Planet since 6 August 2012.
The “Rosetta” mission and the cradle of the cosmos
Two years later, in August 2014, the “Rosetta” spacecraft reaches comet 67P/Churyumov-Gerasimenko, known for short as “Chury”. After a journey of ten years, five months, four days and 6.4 billion kilometres, the spacecraft becomes the first in the history of space travel to deploy a robot lander on a comet. The scientific question behind what is arguably ESA's most spectacular mission is this: did comets once bring water and life to our Earth?
© ESA / John KrausIn November 2019 Ariane 5 departed the spaceport in French Guiana with two satellites on bord.
All 21 scientific instruments on board work perfectly – after years of deep sleep in icy darkness. Also successful is the complicated landing on the “cradle of the cosmos”, which has been a huge challenge for the experts from Alter Technology, who were responsible for ensuring the reliability of the devices on board before and during the mission.
After all, space is a hostile environment not only for humans, but also for technical devices: The devices must withstand radiation from the sun and the stars, the airlessness of space, extreme temperature fluctuations and the vibrations, shocks and enormous acceleration of the launch. Repairs are impossible in space. In order to ensure that the devices function even after years under extreme extra-terrestrial conditions, the experts first subject them to extreme stress tests by simulating the conditions in space.
Space in your pocket
Today, man-made spacecraft have flown around every planet in our solar system. And while the technological eyes trained on space are increasing our knowledge of the universe with every flight, their near-Earth siblings have long since become indispensable to our everyday lives. Whether it is used in navigation systems, mobile phones or weather services, we can hardly imagine a life without the blessing of satellite technology.
© Getty ImagesWith his company SpaceX, Elon Musk strives to bring man to mars.
In order to satisfy the global appetite for broadband, new companies are increasingly taking to sending satellites into space. “SpaceX” supplies the ISS with its Falcon rocket and has recently placed its first 60 satellites into orbit. Up to 12,000 satellites are planned with which the company run by Tesla founder Elon Musk aims to connect even the most remote parts of the Earth with fast and inexpensive Internet. However, unlike NASA or the ESA, these newcomers in space can’t call on decades of experience.
It’s for this reason that Alter Technology has developed a Big-Data-based search engine for satellite components. New space agencies can use it to draw on the accumulated knowledge of their predecessors in the construction of artificial satellites.
For their part, the latest development from the space mission test experts is based on the Internet: an online platform via which space tests can be carried out remotely. In this way, complex space projects can be launched in a shorter time, so that our hunger for high-speed Internet, but above all our boundless curiosity for distant planets, can be satisfied, if only to some extent.