K star
K-1 (reusable space vehicle)
K40506A
Kaba meteorite
Kagoshima Space Center
kakangariite
Kakeya needle problem
Kakehashi (a.k.a COMETS)
Kakkab (Alpha Lupi)
Kaliningrad
Kaluza-Klein theory
kamacite
Kamerlingh Onnes, Heike (1853–1926)
kampyle of Eudoxus
Kant, Immanuel (1724–1804)
kaolinite
Kapitza, Peter Leonidovich (1894–1984)
Kaplan, Joseph (1902–1991)
Kaposi's sarcoma
kappa curve
Kaprekar constant
Kaprekar number
Kapteyn, Jacobus Cornelius (1851–1922)
Kapteyn's Star (HD 33793)
Kapustin Yar
Kardashev, Nikolai S. (1932–)
Kardashev civilizations
Karin Cluster
Kármán, Theodore von (1881–1963)
karst
karyotype
Kasner, Edward (1876–1955)
Kaus Australis (Epsilon Sagittarii)
Kawasaki disease
Keck Interferometer
Keck Observatory
Keck Telescopes
Keeler, James Edward (1857-1900)
Keenan's System (NGC 5216 and NGC 5218)
Kekulé von Stradonitz, Friedrich August (1829–1896)
Keldysh, Mstislav Vsevolodovich (1911–1978)
Kelly, Thomas (1930–2002)
kelvin (K)
Kelvin, Lord (William Thomson) (1824–1907)
Kelvin-Helmholtz contraction
Klemplerer Rosette
Kennedy, John F. (1916–1963)
Kennedy Space Center (KSC)
Kepler, Johannes (1571–1630)
Kepler Mission
Keplerian orbit
Keplerian rotation curve
Keplerian telescope
Kepler-Poinsot solids
Kepler's conjecture
Kepler's equation
Kepler's laws of planetary motion
Kepler's Star (SN Oph 1604)
keratin
kerogen
kerosene
Kerr black hole
Kerwin, Joseph Peter (1932–)
ketone
ketone bodies
ketonuria
ketosis
Kettering Bug
Key Hole (KH)
Keyhoe, Donald E. (1897–1988)
Khayyáam, Omar (1048–1122)
Khintchine's constant
Kibalchich, Nikolai Ivanovitch (1854–1881)
Kibo module (Japanese Experiment Module on the ISS)
kidney
kidney machine
kidney stone
kieselguhr
Kiku (ETS, Engineering Test Satellite)
kiln
kilogram (kg)
kilohertz (kHz)
kilometer (km)
kiloparsec (kpc)
kimberlite
kinase
kinematics
kinesis
kinetic energy
kinetic temperature
kinetic theory of gases
kinetics, chemical
kingdom
kings problem
kinin
kinship puzzles
Kipp's apparatus
kipuka
Kirchhoff, Gustav Robert (1824–1887)
Kirchhoff's laws
Kirkman, Thomas Penyngton (1806–1895)
Kirkwood, Daniel (1814–1895)
Kirkwood gaps
Kiruna
kite
Kitt Peak National Observatory (KPNO)
Kitt Peak 12-Meter Telescope
Kittinger, Joseph W. (1928–)
KIWI (nuclear reactor series)
Klaproth, Martin Heinrich (1743–1817)
Klass, Philip J.
Klein, Christian Felix (1849–1925)
Klein, Harold P. ("Chuck") (1921–2001)
Kleopatra (minor planet 216)
Klumpke-Roberts, Dorothea (1861–1942)
K-meson
knee
knee disorders
knight's tour
Knoll, Andrew H.
knot
Knuth's up-arrow notation
Koch, Robert (1843–1910)
Koch snowflake
Kochab (Beta Ursae Minoris)
Kodiak Launch Complex
Kohoutek, Comet (C/1973 E1)
Kolmogorov, Andrei Nikolaievich (1903–1987)
Komarov, Vladimir Mikhaylovich (1927–1967)
Korabl-Sputnik
Kordylewski Clouds
Korolev, Sergei Pavlovich (1907–1966)
Koronis family (of asteroids)
Kourou
KPNO
Kraft, Christopher Colombus, Jr. (1924–)
Kramers' law
Kranz, Eugene "Gene" F. (1933–)
Kraus, John D. (1910–2004)
Krebs cycle
KREEP
Krieger, Robert L. (1916–1990)
Krikalev, Sergei Konstantinovich (1958–)
Kronecker, Leopold (1823–1891)
Krüger 60
Krunichev State Research and Production Space Center
krypton
K-T boundary
Kuiper, Gerard Peter (1905–1973)
Kuiper Airborne Observatory
Kuiper Belt
Kuiper Belt object
Kuiper Belt objects, largest
Kummersdorf
Kupon
Kurchatov, Igor (1902–1960)
Kurzweg, Hermann H. (1908–2000)
Kwajalein Missile Range
kwashiorkor
Kyokko