On January 28, 1986, Space Shuttle Challenger exploded 73 seconds after takeoff. It was then the most severe accident in NASA's space program. Challenger was the third of what would eventually become five space shuttles. Before it exploded, the shuttle had completed nine flights.

Space Shuttle Challenger takes off from the Kennedy Space Center in Cape Canaveral. Spectators are applauding. Only seconds later enthusiasm turns into horror. Numerous family members and colleagues of the astronauts are among the viewers.

These seven astronauts were killed in the accident (from left to right): Aerospace engineer Ellison Onizuka, pilot Mike Smith, elementary school teacher Christa McAuliffe, test pilot and aerospace engineer Dick Scobee, payload specialist Greg Jarvis, physicist Ron McNair and electrical engineer and specialist for telemetry Judith Resnik.

McAuliffe was supposed to become the first teacher in space - and an inspiration for many other students and teachers. In subsequent years, many astronauts carried on with the idea of bringing science and technology back from space into the classroom. Here, McAuliffe is talking to Barbara Morgan during astronaut training. Morgan stayed behind as a backup for McAuliffe.

One or more o-ring seals failed after a very cold night with freezing temperatures and then high temperatures during takeoff. Exhaust gas came out at the side of the rocket, rather than through the engine. Here the head of the presidential investigation commission William Rogers is testifying at a Senate committee. His deputy, astronaut Neil Armstrong, is listening.

Germany grieved for the dead astronauts as well. Only three month before the accident, the two first West German astronauts Reinhard Furrer and Ernst Messerschmid (first and fifth from left) flew with the same space shuttle. They launched the German-built Spacelab D-1, the first big space exploration project of the Federal Republic of Germany.

Two and a half years after the tragedy, NASA resumed shuttle flights. On December 29, 1988, Space Shuttle Discovery took off from Cape Canaveral. Again there were glitches: Parts of a tank's insulation broke off. Nevertheless, Discovery became one of the most successful space shuttles, and the most used one, too - between 1984 and 2011, it took off 39 times.

17 years and 87 space shuttle flights after the Challenger tragedy, criticism of the program had nearly died down. Then a second catastrophe happened: Space Shuttle Columbia broke apart during reentry into Earth's atmosphere on February 1, 2003. All seven crew members died. The likely cause was damage a wing had suffered during takeoff, when it was hit by a piece of fuel-tank insulation foam.

Despite the two accidents, NASA's shuttle program can look back on a proud history: 133 flights were concluded successfully. Here, Space Shuttle Atlantis is approaching the International Space Station (ISS). Without the shuttles, it would have been almost impossible to build the ISS. The Russian Soyuz capsule in the foreground is today's standard vehicle for human space travel to the ISS.

In comparison to the ISS, Space Shuttle Endeavour looks almost tiny on this picture. It is one of very few photos ever taken of a docked space shuttle at the station. Italian astronaut Paolo Nespoli had the opportunity to take the shot in 2011 from inside a Soyuz space capsule on the way home from the ISS.

Space shuttle Atlantis is docking on to the ISS for the second to last time in May 2010. Its last flight took place one year later. By then, space shuttles had delivered uncountable telecommunication-, navigation- and research satellites into their orbit, including space telescope Hubble. They retrieved and repaired satellites and even visited the Russian space station Mir.

Space Shuttle Endeavour flies for the last time - mounted on a special Boeing 747 Jumbo Jet. The plane took the shuttle to its retirement home, the California Science Center in Los Angeles. They took a detour to do a final flyby over the Golden Gate Bridge and several cities along the West Coast. Endeavour had seen its last space flight in May 2011, Atlantis' was in July of the same year.

The future of human space travel looks somewhat like the past: The newest NASA spaceship will be Orion. Its design recalls the first Apollo spaceships. The European Space Agency (ESA) will deliver important components for Orion. The new spaceship will be bigger than the Soyuz spacecrafts and also travel farther - to the moon or maybe even to Mars one day.

Dennis Tito was and always will be the first civilian to travel to space. Tito had been a NASA engineer before turning to finance. He had always dreamed of a trip to space and is said to have paid $20 million to have his dream come true. It was hard convincing the big space agencies, but on April 28, 2001, Tito took a ride on a Soyuz rocket and spent six days at the International Space Station.

So, the name's fitting — shuttle-worth. But beyond that you'll quickly see a bias emerge. The first space tourists were all nerdy engineers… and all but one were MEN. South African Mark Shuttleworth, an internet and software engineer, flew a year after Tito and is celebrated as the first African in space. We're still waiting for the first Black African to make it — not for want of trying, though.

There's never been a Black African astronaut, neither agency-based nor a tourist. Mandla Maseko, a DJ from a township in Pretoria, South Africa, was due to be the first "Afronaut" until he died in a road accident at the age of 30. Maseko had won his chance through a private venture called Ace Apollo Space Academy. Seen as an inspirational figure, he said: "Defy gravity in everything that you do."

The third "official" space tourist was millionaire scientist Gregory Olsen. As Tito and Shuttleworth before him, Olsen bought his ticket through a company called Space Adventures and flew on a Russian Soyuz rocket. Olsen sold his own company, Sensors Unlimited, which under new owners Collins Aerospace is a NASA contractor, to pay his way. And he says he'd sell another firm to do it all again.

So, it's not only boys who dream of the stars. Anousheh Ansari dreamed of space as a child as well. An engineer, internet technologist and co-founder of the XPRIZE Foundation, Ansari spent 11 days in space in 2006. She is described as the first astronaut of Iranian descent and the first Muslim woman in space. Her foundation champions itself as having "ignited a new era for commercial spaceflight."

In 1991, Helen Sharman became the UK's first astronaut. Sharman conducted scientific experiments on the Soviet/Russian space station Mir, so hers was a mission in the traditional sense. We're including Sharman because her mission started as a commercial venture, but the company failed. The Soviets, whose idea it was anyway, paid in an act of bettering relations between them and the West.

Charles Simonyi is the first space tourist to have taken two trips. The billionaire software engineer first flew in 2007 and then again in 2009. But Simonyi holds other records, too. At the age of 13, he was selected as a junior astronaut in his native Hungary, and he developed the world's first WYSIWYG (what-you-see-is-what-you-get) text editor, Bravo. He thinks humans will live in space one day.

British-American Richard Garriott (left) had an early interest in space travel due to the fact that his dad, Owen, was a NASA astronaut. Family friends and neighbors were astronauts, too. But he became a computer games developer and that's how he paid for his trip in 2008 — but he was also an investor in the space tourism company, Space Adventures. He's known to dress up as a medieval knight.

A native of Quebec, Guy Laliberte is the original creative mind behind the world-famous circus company, Cirque du Soleil ("Circus of the Sun"). He spent 10 days at the International Space Station in 2009 and is the last of the old-school space tourists. Following Laliberte's trip, no tourists flew for over a decade. This shot of a Soyuz capsule returning to Earth was almost the end of it. Until…

Boys and their toys: Virgin Galactic's Richard Branson just had to pip Amazon-man Jeff Bezos at the post. His reward? The US Federal Aviation Administration grounded Branson's SpaceShipTwo for deviating from its flight path as it descended from the edge of space on July 11, 2021. Got to hand it to Branson, though — he's been at it for decades. SpaceShipOne won the Ansari XPRIZE in 2004.

Branson and Bezos (in hat) are competitors. They're also in a private space travel clique with common goals and would get nowhere without each other — or early test pilots Brian Binnie and Mike Melvill and investors like Microsoft co-founder Paul Allen or Peter Diamandis, co-founder of Space Adventures and XPRIZE. On July 20, 2021, Bezos and three others took a suborbital flight. Will you be next?