- How many expeditions attempted Everest before Hillary and Norgay's successful 1953 summit, and what happened to George Mallory in 1924?
Human Spaceflight
Crewed missions, astronauts, and life in space.
- What scientific question about spaceflight did Laika's mission actually answer?
- What major crewed spaceflight programs did NASA's first decade eventually include?
- How long did Yuri Gagarin's Vostok 1 flight last, and what altitude and orbital path did it follow?
- Why did Gagarin eject from the capsule and land separately by parachute rather than riding it down?
- Why were Vostok 1's automatic controls preferred over manual controls, given uncertainty about human function in weightlessness?
- What criteria did the Soviet space program reportedly use to select Gagarin from the cohort of twenty cosmonaut candidates?
- How did Alan Shepard's suborbital Freedom 7 flight differ from Yuri Gagarin's full orbital flight three weeks earlier?
- What points did American officials emphasize about Shepard's flight — manual control and live television broadcast — to contrast it with the Soviet flight?
- How did Shepard's flight lead directly to President Kennedy's announcement of the Moon landing goal before Congress?
- What altitude did Freedom 7 reach during its parabolic arc over the Atlantic?
- What warning did Glenn's telemetry sensors give about the Friendship 7 heat shield, and was it accurate?
- Why did mission control decide to keep the retrograde rocket package attached during re-entry?
- How many orbits of Earth did John Glenn complete, and how fast was Friendship 7 traveling?
- Why is John Glenn remembered as a first when Soviet cosmonauts had already orbited Earth?
- Why did Valentina Tereshkova's parachuting experience make her a strong candidate for the Vostok program?
- How long did Tereshkova spend in orbit aboard Vostok 6, and how did that compare to American astronauts' combined flight time?
- What was the relationship between the concurrent Vostok 5 and Vostok 6 missions?
- How long after Tereshkova's flight did it take for another woman to reach space?
- Why did Leonov's spacesuit balloon outward in the vacuum of space, and how did that nearly strand him outside Voskhod 2?
- What risky decision did Leonov make to fit back through the airlock, and what danger did it expose him to?
- Why did the Soviet press not report the near-disaster during Leonov's spacewalk at the time it happened?
- What device did Edward White use to maneuver during his spacewalk, and why did it stop working so quickly?
- How long did White's spacewalk last, and what route did he drift along above Earth?
- Why did White resist the order to return inside the capsule, and what did he later say about that moment?
- How did White's death in the Apollo 1 fire two years later change how his spacewalk photographs are viewed?
- How many structural problems had Soviet engineers identified with Soyuz 1 before it launched?
- Why did Yuri Gagarin's attempt to ground Komarov fail to stop the launch?
- What sequence of technical failures caused the Soyuz 1 capsule to crash during re-entry?
- How did the Soyuz spacecraft design change after the accident, and why has it remained in use for so long?
- Why did Armstrong take manual control of the lunar module during descent?
- How did cosmonauts transfer between Soyuz 4 and Soyuz 5 during their 1969 docking?
- Why has no later crew transfer between docked spacecraft used a spacewalk instead of an internal hatch?
- What Soviet lunar mission plans was the Soyuz 4/5 docking meant to test?
- What caused the oxygen tank inside Apollo 13's service module to rupture on 13 April 1970?
- How did the Apollo 13 crew improvise a working carbon dioxide scrubber from mismatched parts?
- How did Alan Shepard become the oldest person to walk on the Moon after being medically grounded for a decade?
- How did Alan Shepard's golf shots on the Moon behave differently than they would have on Earth?
- How did the docking adaptor used in Apollo-Soyuz allow incompatible American and Soviet spacecraft to connect?
- What did the astronauts and cosmonauts actually do during the 44 hours of joint operations in orbit?
- Why couldn't NASA boost Skylab into a higher, safer orbit before it fell?
- How did higher-than-expected solar activity speed up Skylab's reentry?
- Where did Skylab's debris land, and what was the Esperance council's response?
- How long did it take NASA to pay the littering fine, and who eventually covered it?
- What happened to volcanologist David Johnston during the eruption, and what was his final radio message?
- How did Sally Ride end up applying to NASA's astronaut program in 1977?
- What was Sally Ride's role during the STS-7 mission aboard Challenger in 1983?
- What robotic system did Ride help develop and then operate in orbit?
- What roles did Sally Ride take on after her spaceflights, including on shuttle accident investigations?
- How did the Manned Maneuvering Unit's nitrogen thrusters let Bruce McCandless II move away from the shuttle without a tether?
- How far did McCandless travel from the orbiter during the first untethered spacewalk?
- Why had every spacewalk before STS-41-B relied on a physical tether to the spacecraft?
- What was significant about McCandless having helped design the equipment he later used to make the first untethered spacewalk?
- What was Zarya's function as the first module of the International Space Station, before any other module arrived?
- Who made up the Expedition 1 crew that first occupied the ISS?
- What condition was the space station in when Expedition 1 arrived in November 2000?
- How long has the International Space Station been continuously occupied since Expedition 1?
- Why did NASA object to Dennis Tito's visit to the International Space Station while Russia agreed to fly him?
- How much did Dennis Tito pay for his trip and how long did he spend aboard the ISS?
- Who was Yang Liwei, and how was he selected for the Shenzhou 5 mission?
- How long did Yang Liwei spend in orbit, and where did he land?
- What made China the third nation to achieve independent human spaceflight?
- How did American astronauts reach the International Space Station after the shuttle program ended?
- When did continuous human habitation of the ISS begin, and how many astronauts and experiments has the station hosted since?
- What crewed spaceflight distance record did Artemis II set, and how did it surpass Apollo 13?