Space Exploration Timeline, 1609–2030: From Kepler's Laws to Artemis

A liquid-fuelled rocket flies — 12.5 metres high

On a farm in Auburn, Massachusetts, Goddard launched a rocket burning gasoline and liquid oxygen. It rose about 12.5 metres, travelled about 56 metres sideways and came down in a snowy field. The numbers look like a toy's, but the principle of the liquid rocket — feeding fuel and oxidiser into a combustion chamber and burning them continuously, with the flow under control — worked in practice for the first time. The Saturn V that carried Apollo to the Moon is an extension of the same idea.

• Altitude ~12.5 m
• Distance downrange ~56 m

People and institutions: Robert H. Goddard

• Liquid-Propellant Rocket Development — Smithsonian Miscellaneous Collections 95(3) (1936), Smithsonian Research Online
• Robert Goddard and the First Liquid-Propellant Rocket — Smithsonian National Air and Space Museum (2016)

The V-2 — the first human-made object to reach space was a weapon

Nazi Germany's V-2 (A4) was a liquid-fuelled ballistic missile developed by a team including Wernher von Braun. A test launch on 20 June 1944 climbed to roughly 170-odd kilometres and is regarded as the first human-made object to enter space. It was built with concentration-camp labour. Michael Neufeld of the Smithsonian's National Air and Space Museum estimates that at least 10,000 people died producing it — twice the roughly 5,000 killed by its attacks. After the war its engineers and hardware were divided between the United States and the Soviet Union, and became the starting point of both countries' rocket programmes.

• Deaths in production (minimum estimate) ~10,000
• Deaths from attacks ~5,000

People and institutions: Wernher von Braun / Walter Dornberger

NoteSources put the altitude at roughly 174–176 km. No boundary of space had been defined at the time.

• "Wonder Weapons" and Slave Labor — Smithsonian National Air and Space Museum (June 2020), Michael J. Neufeld

The 23-centimetre Pencil rocket — where Japanese rocketry began

Hideo Itokawa and colleagues at the University of Tokyo's Institute of Industrial Science fired a tiny solid-fuel rocket 23 centimetres long horizontally, in a half-buried trench on a former factory site in Kokubunji, Tokyo. Firing it sideways was partly a matter of having nowhere else, but it also let them send it through a series of wire screens and measure its speed and attitude from the moments each wire broke. Japan had been barred from aeronautical research for some years after the war, so this was a restart from almost nothing. Fifteen years later Japan became the fourth country to put a satellite into orbit on its own rocket.

• Length 23 cm

People and institutions: Hideo Itokawa (糸川英夫) / Institute of Industrial Science, University of Tokyo

• 国分寺のペンシル (The Pencil rocket at Kokubunji) — ISAS/JAXA, History of Japanese Space Development
• ISASニュース No.289 (ISAS News no. 289), April 2005 — 50th anniversary of the Pencil rocket — Institute of Space and Astronautical Science, JAXA (2005)

Sputnik 1 — the first human-made object in orbit

The Soviet Union launched a polished metal sphere about 58 cm across, weighing a little over 83 kg and trailing four antennas, and sent it round the Earth once every 96 minutes or so. It carried nothing but a radio transmitter, and for the three weeks until its batteries died its signal could be picked up by receivers around the world. It came 270 years after Newton's thought experiment and 54 after Tsiolkovsky's equation. The political shock — the same rocket could carry a nuclear warhead to the United States — mattered even more than the technical feat, and led to the founding of NASA the following year.

• Mass ~83 kg
• Orbital period ~96 min

People and institutions: Sergei Korolev (Сергей Королёв) / OKB-1

• Sputnik and the Origins of the Space Age — NASA History Office, Roger D. Launius

Gagarin circles the Earth in 108 minutes

In Vostok 1, the Soviet cosmonaut Yuri Gagarin went once around the Earth, the first human being in space. The flight lasted 108 minutes, and almost everything was controlled from the ground or by automatic systems, because nobody knew whether a person could think clearly while weightless. On the way down Gagarin ejected from the capsule and came down under his own parachute, separately from it, because the capsule's landing was too hard to protect its occupant.

• Flight time 108 min

People and institutions: Yuri Gagarin (Юрий Гагарин) / Sergei Korolev (Сергей Королёв)

• April 1961 — First Human Entered Space — NASA (image article)
• The flight of Vostok 1 — European Space Agency; archived by NASA Safety and Mission Assurance

Apollo's guidance computer keeps the infant integrated-circuit industry afloat

A spacecraft bound for the Moon has to be able to work out where it is even when contact with the ground is lost. In 1962 Eldon Hall and colleagues at the MIT Instrumentation Laboratory decided to build the guidance computer from integrated circuits, which then had almost no track record. They restricted themselves to a single type of circuit, the NOR gate, bought it in bulk and tested it exhaustively. According to the Computer History Museum, in 1963 the programme consumed about 60 percent of all integrated circuits made in the United States. The volume of orders hardened the manufacturing process and drove prices down — a case of space exploration nurturing the semiconductor industry.

• Share of US IC output consumed in 1963 ~60%
• ICs in the Block II computer 2,756

People and institutions: Eldon C. Hall / MIT Instrumentation Laboratory / Fairchild Semiconductor

• Journey to the Moon: The History of the Apollo Guidance Computer — AIAA Library of Flight (1996), Eldon C. Hall
• Silicon Chips Take Man to the Moon — Computer History Museum (July 2019), David A. Laws

Apollo 11 — people land on the Moon and bring rocks home

Neil Armstrong and Buzz Aldrin set the lunar module down in the Sea of Tranquility and, in a moonwalk of about two and a half hours, collected 21.5 kg of rock and soil. During the descent the guidance computer repeatedly raised alarms that it was overloaded, but it had been designed to drop low-priority tasks and keep the essential calculations running, so the landing went ahead. It was only twelve years after Sputnik. That speed, though, was bought by a race that claimed a large slice of a national budget, and once the race was over no one went back to the Moon for more than fifty years.

• Samples returned 21.5 kg
• After Sputnik 12 years

People and institutions: Neil Armstrong / Buzz Aldrin / Michael Collins / NASA

• Apollo 11 Mission Report (MSC-00171) — NASA Manned Spacecraft Center (1969), NASA Technical Reports Server

Ohsumi — Japan's first satellite, put into orbit without a guidance system

The University of Tokyo's Institute of Space and Aeronautical Science put the 24 kg Ohsumi into orbit on the fifth L-4S rocket. It followed four failures and made Japan the fourth country, after the Soviet Union, the United States and France, to do so. The rocket had no guidance system to steer it. Instead, the launch angle and the natural gravity-driven arc of the flight were calculated so precisely that the top stage could be ignited at the moment it was pointing close to horizontal. Its radio lasted only about half a day, but the satellite stayed in orbit for 33 years.

• Mass 24 kg
• Time in orbit 33 years (re-entered 2003)

People and institutions: Institute of Space and Aeronautical Science, University of Tokyo / Hideo Itokawa (糸川英夫)

• 人工衛星「おおすみ」 (The Ohsumi satellite) — Institute of Space and Astronautical Science (ISAS/JAXA), past missions

Voyager — riding a planetary alignment that comes once in 175 years

In 1965 Gary Flandro, a graduate student at JPL, found by calculation that in the late 1970s Jupiter, Saturn, Uranus and Neptune would be lined up so that a spacecraft could hop from one to the next by gravity assist. Such an alignment comes round only about once every 175 years. The two Voyagers launched in 1977 took the chance, and Voyager 2 remains the only spacecraft to have visited all four giant planets. It reached Neptune in 12 years; a Hohmann transfer would have taken about 30.

• Alignment recurs every ~175 years
• Time to Neptune 12 years (~30 by Hohmann transfer)

People and institutions: Gary Flandro / NASA / Jet Propulsion Laboratory

NoteVoyager 2 was launched first, on 20 August 1977, and Voyager 1 on 5 September. Flandro's paper is Astronautica Acta 12, 329–337 (1966); its publisher record could not be reached, so his oral history is cited instead.

• Gary Flandro (PhD '67), Aerospace Engineer — oral history — Caltech Heritage Project
• The Voyager 2 Encounter with the Neptunian System — Science 246(4936), 1417–1421 (1989), E. C. Stone and E. D. Miner

A spacecraft is parked at a Lagrange point for the first time

NASA's ISEE-3 entered an orbit around the Lagrange point between the Sun and the Earth, about 1.5 million km from Earth. From this "halo orbit", designed by Robert Farquhar and colleagues, the spacecraft never passes into Earth's shadow and can watch the solar wind about an hour before it arrives at Earth. It was a practical use of Lagrange's calculation 206 years after he made it. Today the solar observatory SOHO sits at the same point, and the James Webb Space Telescope at the matching point on the far side of the Earth.

• After Lagrange's calculation 206 years
• Distance from Earth ~1.5 million km

People and institutions: Robert W. Farquhar / NASA

• The Flight of ISEE-3/ICE: Origins, Mission History, and a Legacy — J. Astronautical Sciences 49, 23–73 (2001), R. W. Farquhar

The Space Shuttle — reuse was supposed to make it cheap

NASA's Space Shuttle was built on the idea that flying a winged vehicle again and again would make launch cheap, with dozens of flights a year. In practice every flight required extensive inspection and refurbishment, and thirty years brought only 135 flights. Roger Pielke Jr. and Radford Byerly put the programme's total cost at roughly USD 1.5 billion per flight. The Challenger (1986) and Columbia (2003) disasters killed fourteen people. Reuse was the right idea, but the shuttle showed that it saves nothing if refurbishment costs too much.

• Flights (1981–2011) 135
• Programme cost per flight ~USD 1.5 bn

People and institutions: NASA

• Shuttle programme lifetime cost — Nature 472, 38 (2011), R. Pielke Jr. and R. Byerly
• The Recent Large Reduction in Space Launch Cost (ICES-2018-81) — 48th International Conference on Environmental Systems (2018), H. W. Jones, NASA Ames

The ion engine becomes a spacecraft's main propulsion in deep space

NASA's Deep Space 1 was the first deep-space mission to rely on an ion engine — one that accelerates xenon with electric fields — as its main propulsion. Its push is only enough to hold up about ten grams, yet for the same amount of propellant it delivers roughly ten times the change in speed of a chemical rocket, and it can run without stopping for months. Goddard had written down the idea of electric propulsion in a 1906 notebook; it took almost ninety years to put into service. Japan's Hayabusa used engines of the same kind for its round trip to an asteroid.

• Specific impulse ~3,100 s (chemical: 300–450 s)

People and institutions: NASA / Jet Propulsion Laboratory / Marc D. Rayman

• Results from the Deep Space 1 technology validation mission — Acta Astronautica 47(2–9), 475–487 (2000), M. D. Rayman et al.
• A Critical History of Electric Propulsion: The First 50 Years (1906–1956) — J. Propulsion and Power 20(2), 193–203 (2004), E. Y. Choueiri

IKAROS — a sail pushed by sunlight

JAXA's IKAROS unfurled a sail 20 m across, made of polyimide film about 7.5 micrometres thick, and demonstrated for the first time in interplanetary space that the faint pressure of sunlight can accelerate a spacecraft. Thin solar cells on the sail tested power generation at the same time. That light pushes on what it strikes follows from Maxwell's electromagnetism and was confirmed experimentally at the start of the twentieth century. Here a way of travelling without spending fuel went from theory to hardware.

• Sail span 20 m
• Film thickness ~7.5 µm

People and institutions: JAXA / Yuichi Tsuda (津田雄一) / Osamu Mori (森治)

• Flight status of IKAROS deep space solar sail demonstrator — Acta Astronautica 69(9–10), 833–840 (2011), Y. Tsuda et al.

Hayabusa — battered, but home with grains from an asteroid

After touching down on the asteroid Itokawa, JAXA's Hayabusa lost its attitude to a fuel leak and fell silent for seven weeks. With its chemical thrusters gone and its ion engines wearing out, the team kept it going by, among other things, running the working parts of different engines together, and it returned to Earth three years late. Analysis of the roughly 1,500 grains in its capsule confirmed that the most common kind of meteorite to fall on Earth — ordinary chondrites — comes from asteroids of this type.

• Grains returned ~1,500
• Return delayed by ~3 years

People and institutions: JAXA / Junichiro Kawaguchi (川口淳一郎) / Hitoshi Kuninaka (國中均)

• Hayabusa Asteroid Explorer Powered by Ion Engines on the way to Earth (IEPC-2009-267) — 31st International Electric Propulsion Conference (2009), H. Kuninaka et al.
• Itokawa Dust Particles: A Direct Link Between S-Type Asteroids and Ordinary Chondrites — Science 333(6046), 1113–1116 (2011), T. Nakamura et al.

An orbital rocket's first stage comes back and lands upright

SpaceX's Falcon 9 for the first time flew its first stage back after a satellite launch and set it down vertically, on rocket thrust, at a landing zone at Cape Canaveral. The first stage is the most expensive part of the rocket, so reusing it cuts the price of launch sharply. By Harry Jones of NASA's count, the cost of lifting a kilogram to low Earth orbit was about USD 62,000 on the Space Shuttle and about USD 2,700 on the Falcon 9 (in 2018 dollars). The cheap reuse the shuttle had promised was achieved by a design that did not need to be rebuilt after every flight.

• Cost per kg to low Earth orbit Shuttle ~USD 62,000 → Falcon 9 ~USD 2,700

People and institutions: SpaceX

NoteThe landing date is not stated in the cited papers (it is from SpaceX's announcement). Costs are Jones's figures in FY2018 dollars, rounded.

• The Recent Large Reduction in Space Launch Cost (ICES-2018-81) — 48th International Conference on Environmental Systems (2018), H. W. Jones, NASA Ames
• Autonomous Precision Landing of Space Rockets — Frontiers of Engineering: Reports on Leading-Edge Engineering from the 2016 Symposium, National Academies Press (2017), L. Blackmore (SpaceX)

DART — hitting an asteroid shows its orbit can be changed

NASA's DART spacecraft struck Dimorphos, a moonlet about 150 m across that orbits the asteroid Didymos, at about 6 km per second. Observations showed that its orbital period had shortened by 33 minutes. The impact's momentum alone should have changed it by only about seven minutes; the recoil from debris blasted off by the collision multiplied the effect several times over. It was the first experiment to show that deflecting a body headed for Earth — until then a defence that existed only on paper — actually works.

• Change in orbital period −33.0 ± 1.0 min

People and institutions: NASA / Johns Hopkins University Applied Physics Laboratory

• Orbital period change of Dimorphos due to the DART kinetic impact — Nature 616, 448–451 (2023), C. A. Thomas et al.

SLIM — landing within 10 metres of the target

JAXA's Smart Lander for Investigating Moon worked out its position during descent by matching camera images of the surface against an onboard map, and just before touchdown had brought its error relative to the target down to 10 m or less. Earlier lunar landings counted as successful if they came down somewhere within a few kilometres. One engine failed during the final descent, so the lander came to rest about 60 m east of the target, tipped over — but the technique of landing where you mean to land was demonstrated. Japan became the fifth country to land on the Moon.

• Landing accuracy (before hazard avoidance) 10 m or better

People and institutions: JAXA / Shinichiro Sakai (坂井真一郎)

• Moon landing results of SLIM: A smart lander for investigating the Moon — Acta Astronautica 235, 47–54 (2025), S. Sakai et al.
• Outcome for the Smart Lander for Investigating Moon (SLIM)'s Moon Landing — JAXA press release, 25 January 2024

Chang'e 6 — the first rocks brought back from the far side of the Moon

China's Chang'e 6 landed in the South Pole–Aitken basin on the far side of the Moon and returned 1,935.3 grams of material to Earth. Because the far side has no direct line of sight to Earth, the landing and sampling were carried out through a relay satellite launched beforehand. Sixty-five years after Luna 3 photographed the far side, the question of why the two hemispheres differ so much can now be studied with actual rocks.

• Samples returned 1,935.3 g

People and institutions: CNSA

NoteThe landing was on 2 June 2024 and the return to Earth on 25 June; the entry is dated by the return.

• Nature of the lunar far-side samples returned by the Chang'E-6 mission — National Science Review 11(11), nwae328 (2024), C. Li et al.

Artemis II — people go to the Moon's vicinity for the first time in 53 years

NASA's Artemis II flew four astronauts in the Orion spacecraft around the far side of the Moon and back in a test flight of about ten days. It was the first time people had gone beyond low Earth orbit since Apollo 17 in 1972. At its farthest the crew was about 406,800 km from Earth, beating the record set by Apollo 13. The crew included an astronaut from the Canadian Space Agency, the first non-American on a crewed flight to the Moon. The mission did not include a landing.

• Farthest distance from Earth ~406,800 km
• Mission length ~10 days

People and institutions: Reid Wiseman / Victor Glover / Christina Koch / Jeremy Hansen / NASA / CSA

NoteLaunched 1 April 2026 and splashed down 10 April (US Pacific time).

• NASA Welcomes Record-Setting Artemis II Moonfarers Back to Earth — NASA news release, April 2026