class M planet n.

an Earth-type planet

Associated chiefly with the US TV series Star Trek.

Memory Alpha


Star Trek

  • ?a1965 G. Roddenberry Original outline for โ€˜Star Trekโ€™ in S. E. Whitfield & G. Roddenberry Making of โ€˜Star Trekโ€™ (1968) i. i. 24 Gene Roddenberry

    You will confine your landings and contacts to Class โ€˜Mโ€™ planets, approximating Earth-Mars conditions.

  • 1968 G.L. Coon Errand of Mercy in J. Blish Star Trek 2 (1968) 41

    Strategically it was the only Class M planet in the disputed zone.

  • 1980 J. C. Haldeman II Perry's Planet ii. 21

    The planet he was referring to is a class M one.

  • 1999 M. J. Friedman My Brotherโ€™s Keeper ii. viii. 124 Michael Jan Friedman bibliography

    โ€˜Sheโ€™s class-Mโ€™, Lieutenant Lynch said of the red-orange world depicted on their main viewscreen.

  • 2021 J. Swallow Dark Veil 71 James Swallow bibliography

    The next nearest habitable Class-M planet is two light-years away, in the middle of the Neutral Zone.


Research requirements

any evidence 1964

Earliest cite

Gene Roddenbery

Research History
Suggested by Mike Christie on 9/15/02: "This is speculative since it may be just Star Trek, but googling '"class M planet" -trek' leads to quite a few hits."

Ben Ostrowsky submitted a 2021 cite from a Star Trek novel by James Swallow.

Last modified 2022-01-15 12:10:10
In the compilation of some entries, HDSF has drawn extensively on corresponding entries in OED.