Since we realized our technology could rocket us from the surface of the Earth into the void, we've been building all sorts of vehicles to take us there. Apart from the Space Shuttle, and the X-Prize winning SpaceShipOne, they've all been describable using one word: capsule. This word describes a small but strong chunk of metal and composites surrounding a fragile bag of air, inside which human passengers are protected from the huge forces of launch, the harsh emptiness of space, and the perilous blazing descent back through the atmosphere to the surface. We've been building them for about fifty years now, and we'll be building them for decades more yet ... so here's a brief past and future history of the space capsule.

Early in 2010 Boeing got an $8 million grant to develop the design for a totally new crew-carrying space capsule: The Crew Space Transportation 100 vehicle. This week Boeing, confident in its initial plans and certain that the real capsule will one day soon rocket into space, signed a memo of agreement with Space Adventures to ferry paying space tourists aloft--their fees will pay for some of the huge costs of the flight. Size: Unconfirmed, but approx. 15 feet across, 8 feet tall. Crew: Up to 7. Payload: To be decided. Flying date: Within the next decade, atop the EELV or Falcon 9 rocket.

Vostok (Russian for East or Orient) was the most famous space vehicle ever when it launched and probably always will be if you're in the know. This is for one reason alone: On April 12, 1961, Vostok 1 launched Yuri Gagarin into space, going boldly where no one had ever gone before. Simple, rugged, with limited equipment--including very limited provision for maneuvers or even retro-burns to de-orbit--it orbited the Earth just once. Deeming the tech too unproven, the Russian authorities had Gagarin bail out of the capsule at 23,000 feet after it had decelerated: Man and capsule parachuted separately to the ground. Two years later, Vostok 6 was Valentina Tereshkova's ride--the first woman in space. Size: 15 feet tall, 7 feet across. Crew: One. Payload: 330 kilos, including pilot's unique seat. Flying date: April 1961 to June 1963, manned missions.

Mercury space capsules were so small and fitted around their astronaut passengers that it was commonly joked that they were not ridden in but worn. The project's goal was to achieve a man in orbit, and it ran from 1959 to 1963. On May 5, 1961, a Mercury capsule, callsigned Freedom 7 and worn by Alan Shepard, rode atop a Redstone rocket to take the first American, and the second human, into space. In February 1962 John Glenn, in a Mercury capsule and an Atlas rocket became the first American to orbit the Earth. Size: 11.5 feet by 6.2 feet. Crew: One. Payload: Almost zero. Flying dates: May 1961 to May 1963, manned missions.

Named after the heavenly twins, Gemini was all about developing the U.S. space effort by enabling two men to go aloft simultaneously. Altogether more sophisticated, some of the control electronics and other systems were outside the crew space, unlike Mercury's cramped interior. It could alter its orbit, used fuel cells for power, and tested out long duration (up to 13 days) missions--despite being only slightly roomier inside than its predecessor. Gemini was Neil Armstrong's, Buzz Aldrin's and Michael Collins' first ride into the void. Size: 18.6 feet tall, 10 feet across. Crew: Two, confined to their seats for the mission duration. Payload: Supplies for two men for up to two weeks in space. Flying dates: March 26 1965 to November 15 1966, manned missions.

Apollo, quite apart from its mythical Greek origins, will be forever famous: It was the culmination of J. F. Kennedy's plan to land men on the Moon and the pinnacle of the space program that started with Mercury. Each Apollo Command Module flew mated to a much larger Service Module, which supplied it with power, propulsion, and expendables like oxygen. A malfunction inside the SM nearly destroyed Apollo 13, shown here being recovered after splashdown, in a mid-space explosion. The conclusion of Apollo 13 is regarded as one of NASA's finest moments, but it's the landing of Armstrong and Aldrin on the Moon that has cemented its place in history. Size: 36.2 feet tall, 12.8 feet across--including Service Module. Crew: Three. Payload: Supplies for three men for up to 100 kilos of Moon rock. Flying dates: October 11th 1968 to December 7 1972, primary manned missions. July 15 1975, modified mission for Soyuz rendezvous in-space.

Soyuz was conceived in the 1960s as a successor to the Voskhod program, and modified and uprated versions of the same technology are flying today--Europe is even soon to launch its own version of the system. Based on Voskhod, it was sophisticated and rugged. Its first manned flight in 1967 sadly resulted in the death of cosmonaut Vladimir Komarov in a crash landing, and three more crew died in Soyuz 11 due to depressurization. It remains, however, the safest and most reliable ride into space. Size: 25.5 feet tall, 8.9 feet across, including service module. Crew: Up to three. Payload: Varies, based on version, but can return many kilos of samples, waste and equipment to Earth in addition to the crew. Flying dates: October 1968 to present, and probably the next 10 years--manned missions.

Shenzhou, which means Divine Craft, is China's capsule for manned space flight. It's based upon the Russian Soyuz design, but uses China's own touches and is very much a new spacecraft that's bigger than its inspiration. Carried along a Long March 5 rocket, its first unmanned flight was in November 1999, and on October 15 2003 a Shenzhou capsule carried the first Chinese astronaut Yang Liwei into space. Many more flights are planned, and the capsule will be integral to China's ambitions for space stations and Moon missions. Size: 30.3 feet tall, 9.1 feet wide including service module. Crew: Up to three. Payload: Unknown. Flying dates: October 15 2003 to present.

Dragon will be the first non-government-sponsored traditional space capsule to fly with people aboard, built by the private company SpaceX. In its initial configuration it's a pure cargo vessel, designed to supply the International Space Station in the post-Shuttle era, but SpaceX is proceeding with the complex process of getting it man-rated. Size: 9.5 feet tall, 11.8 feet across (without service module). Crew: Up to seven. Payload: Up to 6,000 kilos on launch, 3,000 on return to Earth. Flying dates: Stripped-down qualification version, June 2010.

Orion is the last viable element of Project Constellation--the ambitious project initiated by President George W. Bush to return humans to the Moon, and then go beyond. The Obama administration has slashed Constellation's budget, and redirected NASA's efforts away from most of its core plans, but Orion remains as a NASA-directed crew transport capsule which will be the hub of manned space flight after the Shuttle retires. Orion unashamedly takes much of its design inspiration from the Apollo era spacecraft, with materials developed during the Shuttle program. Technology demonstrator mock-ups have been constructed, and several key components, including the powerful rocket launch abort system, have been designed and tested to satisfaction. Size: 10 feet 10 inches tall, 16 feet 6 inches in diameter (crew module alone). Crew: Four to six astronauts. Payload: Still to be determined (dependent on final vehicle mass). Flying dates: A manned mission could occur in 2015, assuming Orion continues to attract funding.