- Cornwell, Bryce
- Ibn Al- Khattâb, Omar
- Kaczynski, Theodore
- Kaplan, Joseph
- Kardashev, Nikolai Semenovich
- Katchen, Lee
- Kaufmann, Frank 🤥
- Kayal, Hakan
- Kazantsev, Alexandr N.
- Kean, Leslie
- Keel, John
- Keel, John A.
- Keldysh, Mstislav V.
- Kelleher, Colm
- Kennedy, John Fitzgerald
- Kennedy, Robert
- Kepler, Johannes
- Keyhoe, Donald E.
- Khadidja
- Kilgallen, Dorothy
- Killian, Peter
- King, George
- Kirkpatrick, Sean
- Kirkwood, Guy
- Kisling, Jean
- Kissinger, Henri
- Klass, Philip J.
- Kleyweg, RH
- Klinn, Robert B.
- Klotz, James
- Knowles, Herbert
- Koi, Isaac
- Korff, Kal
- Korolev, Serguei
- Kottmeyer, Martin S.
- Krine, Jack
- Kudou, Masaaki
- Kuettner, Joachim P.
- Kuhn, Thomas Samuel
- Kuiper, Gerard
- Kurchatov, Igor
- Kurth, Douglas
- Mel Noel
- Noall
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