Human Tech Tree

Earth & Cosmos

Space & Astronomy

51 points from the earliest roots to the research frontier: 33 researched, 6 current research, 6 unsolved and 6 that become possible once they are solved. State of knowledge: October 2026.

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Antiquity3000 BC – 500 AD

  • Ancient astronomy~150 ADResearchedBabylonian records and Greek geometry produced models of the sky that predicted eclipses and planets for 1,500 years.

Middle Ages & Renaissance500 – 1700

  • Gunpowder Rockets (Fire Arrows)~1232ResearchedChinese defenders at Kaifeng (1232) use 'arrows of flying fire': the first documented rockets, driven by gunpowder.
  • Heliocentric world view1543ResearchedCopernicus put the Sun at the centre and Kepler found elliptical orbits; Earth became one planet among others.
  • The telescope1608ResearchedDutch lens makers sought the first telescope patents in 1608; from 1609 Galileo used one to see Jupiter's moons, lunar mountains and Venus's phases.
  • Reflecting Telescope1668ResearchedNewton builds the first working reflecting telescope in 1668, using a mirror instead of a lens to avoid colour errors.

Industrial Age1700 – 1900

  • Discovery of Neptune1846ResearchedLe Verrier calculates from Uranus's orbit where an unseen planet must be, and Galle finds Neptune there on 23 September 1846.

Machine Age1900 – 1945

  • Tsiolkovsky's Rocket Equation1903ResearchedKonstantin Tsiolkovsky derives (1903) how a rocket's speed depends on its exhaust velocity and fuel fraction, and proposes staging and liquid fuels.
  • Cepheid distance yardstick1912ResearchedHenrietta Leavitt found in 1912 that a Cepheid star's pulsation period reveals its true brightness, giving a yardstick across space.
  • Other Galaxies (Hubble)1924ResearchedEdwin Hubble finds Cepheid stars in the Andromeda nebula in 1923-24 and shows it lies far outside the Milky Way: the universe holds many galaxies.
  • Hohmann Transfer Orbits1925ResearchedWalter Hohmann shows in 1925 that the cheapest path between two circular orbits is an ellipse touching both, with two short engine burns.
  • Goddard's Liquid-Fuel Rocket1926ResearchedRobert Goddard launches the first liquid-fuel rocket (gasoline and liquid oxygen) in Massachusetts on 16 March 1926.
  • Radio astronomy1933ResearchedKarl Jansky detected radio waves from the centre of the Milky Way in 1932-33, opening a window beyond visible light.
  • Liquid-fuel rocket (V-2)1942ResearchedGermany's V-2 (1942-44) is the first rocket to reach space.

Atomic & Space Age1945 – 1990

  • First satellite (Sputnik)1957ResearchedOn 4 October 1957 the Soviet Sputnik 1 became the first artificial satellite and started the space race.
  • Apollo Guidance Computer1961-1969ResearchedMIT builds the Apollo Guidance Computer in the 1960s with integrated circuits; it lands crews on the Moon in 1969.
  • First human in space1961ResearchedYuri Gagarin orbited Earth once on 12 April 1961 in Vostok 1, proving that humans can survive spaceflight.
  • Pulsars1967ResearchedJocelyn Bell Burnell found regularly pulsing radio sources in 1967: spinning neutron stars, the densest stars known.
  • Moon landing1969ResearchedApollo 11 landed Neil Armstrong and Buzz Aldrin on the Moon on 20 July 1969; twelve people walked on it by 1972.
  • Black Holes (Cygnus X-1)1971-72ResearchedIn 1971-72 astronomers link the bright X-ray source Cygnus X-1 to a star with an unseen, very compact partner: the first strong black hole candidate.
  • Space stations1971ResearchedFrom Salyut 1 (1971) to the ISS (crewed continuously since November 2000), stations taught humans to live and work in orbit for months.
  • Deep-space probes (Voyager)1977ResearchedRobotic probes visited every planet; Voyager 1 and 2 (launched 1977) toured the outer planets and Voyager 1 entered interstellar space in 2012.
  • Space Shuttle1981ResearchedNASA's winged Shuttle (1981-2011) was the first partly reusable crewed spacecraft, but each flight cost far more than planned.

Digital Age1990 – 2015

  • Hubble Space Telescope1990ResearchedLaunched in April 1990, Hubble sees the universe without atmospheric blur and helped fix the age and expansion rate of the cosmos.
  • Segmented-Mirror Telescopes1993ResearchedKeck I (1993) joins 36 hexagonal mirror segments, adjusted continuously by computer, into one 10 m mirror.
  • Exoplanet discovery1995ResearchedMichel Mayor and Didier Queloz found 51 Pegasi b in 1995, the first planet around a Sun-like star, opening the era of exoplanet science.
  • Satellite navigation (GPS)1995ResearchedGPS reached full operational capability in 1995; atomic clocks on satellites let receivers fix their position anywhere to metres.
  • Mars rovers1997ResearchedFrom Sojourner (1997) to Spirit, Opportunity, Curiosity and Perseverance, rovers showed that ancient Mars was wet and habitable.
  • Ion Thruster1998ResearchedNASA's Deep Space 1 (1998) is the first probe to use an ion engine as main propulsion, with exhaust speeds several times that of chemical rockets.
  • Kepler Planet Census2009ResearchedNASA's Kepler telescope (launched 2009) watches 150,000 stars for the tiny dimming of passing planets and finds thousands.

Present2015 – Oct 2026

  • Reusable rockets2015Current researchFalcon 9 landed its first stage in December 2015 and now flies the same booster dozens of times; Starship aims for full reuse.
  • Gaia: 3D Map of the Milky Way2018–2022ResearchedESA's Gaia charted the positions, distances and motions of nearly two billion objects; its 2018 and 2022 data releases underpin studies of the Galaxy.
  • Far-Side & Polar Moon Landings2019-2023ResearchedChina's Chang'e-4 made the first far-side soft landing (3 January 2019); India's Chandrayaan-3 landed near the south pole on 23 August 2023, the…
  • Satellite mega-constellations2019Current researchSeveral competing constellations of thousands of satellites now crowd low Earth orbit; Starlink alone has more than 11,000 up, raising problems for…
  • Asteroid Sample Return2020–2023ResearchedHayabusa2 (December 2020) and OSIRIS-REx (September 2023) returned samples of asteroids Ryugu and Bennu; Bennu's held amino acids and all five…
  • Commercial Crew Spaceflight2020ResearchedOn 30 May 2020 SpaceX's Crew Dragon Demo-2 flew two NASA astronauts to the ISS, the first US crewed launch since 2011 and the first by a commercial…
  • James Webb Space Telescope2021Current researchLaunched in December 2021, Webb sees the first galaxies and probes exoplanet atmospheres in the infrared.
  • Chang'e-6 far-side samples2024Current researchChina's Chang'e-6 returned the first samples from the Moon's far side in June 2024, from the South Pole-Aitken basin region.
  • Artemis II lunar flyby2026Current researchIn April 2026 four astronauts flew around the Moon and back, the first crewed trip beyond low Earth orbit since 1972.
  • Rubin and Roman sky surveys2026Current researchRubin's 3.2-gigapixel camera began a 10-year repeated survey of the southern sky in June 2026, and NASA's Roman telescope launched on 30 August 2026.

Research Frontier · Todayunsolved as of Oct 2026

  • Beyond chemical rocketsopenUnsolvedNuclear thermal or nuclear-electric propulsion could cut travel time or fuel mass for deep-space missions, but no nuclear rocket has flown.
  • Finding extraterrestrial lifeopenUnsolvedNo life outside Earth has ever been confirmed; the best candidates are Mars, icy ocean moons and the atmospheres of exoplanets.
  • Humans on MarsopenUnsolvedLanding and living on Mars needs orbital refuelling, landing ships of tens of tonnes and protecting people for years; none is demonstrated yet.
  • Planetary defenseopenUnsolvedWe can nudge a small asteroid (DART, 2022), but have found fewer than half of the large ones and never tested on a big one.
  • Radiation and life supportopenUnsolvedBeyond Earth's magnetic field, cosmic rays and solar storms expose crews to radiation, and food, air and water must be recycled for years.
  • Space debris controlopenUnsolvedDead satellites and fragments are piling up in orbit; collisions create more debris, and there is no way yet to clean up at scale.

If Solvedbecomes possible

  • Permanent Moon Base2030s?If solvedA permanently staffed outpost near the lunar south pole; NASA announced a plan in March 2026 targeting a permanent presence by 2036.
  • Fast Solar System Transit2040s?If solvedNuclear-powered spacecraft routinely carry cargo and crews across the inner solar system faster and with less propellant than chemical rockets.
  • Operational asteroid defense2040s?If solvedA near-complete asteroid catalogue and ready interceptors able to deflect a threatening object years before impact.
  • Permanent Mars base2040s?If solvedA permanently staffed outpost on Mars making its own air, water and propellant from local resources.
  • Sustainable Earth orbit2040s?If solvedOrbits where debris is tracked, new satellites de-orbit reliably, and old wrecks are removed.
  • Proof of life beyond EarthopenIf solvedAn accepted detection of life, even microbes, on another world would show that life is not unique to Earth.