Definitions

from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun The point in an orbit around the moon where the orbiting body is closest to the moon.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun astronomy The point of an elliptical lunar orbit where the distance between the satellite and the Moon is at its minimum.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun periapsis in orbit around the moon

Etymologies

from The American Heritage® Dictionary of the English Language, 4th Edition

[peri– + Latin lūna, moon; see lune.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From peri- ("near") + Latin lūna ("moon").

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Examples

  • China's first lunar probe, Chang'e-1, successfully completed its first braking at perilune and entered the moon's orbit Monday morning, becoming China's first circumlunar satellite.

    Asia Now Controls Lunar Orbit - NASA Watch 2007

  • China's first lunar probe, Chang'e-1, successfully completed its first braking at perilune and entered the moon's orbit Monday morning, becoming China's first circumlunar satellite.

    NASA Watch: November 2007 Archives 2007

  • China's first lunar probe, Chang'e-1, successfully completed its first braking at perilune and entered the moon's orbit Monday morning, becoming China's first circumlunar satellite.

    NASA Watch: Keith Cowing: November 2007 Archives 2007

  • A standard altimeter could not tell the astronauts when they reached their perilune because an altimeter was an instrument that determined altitude based on changes in atmospheric pressure and the Moon has no atmosphere.

    First Man James R. Hansen 2005

  • Aldrin reported that DOI had come off extremely well, and that it had put Eagle into almost the exact, predetermined perilune from which it was to start its final, powered descent.

    First Man James R. Hansen 2005

  • A standard altimeter could not tell the astronauts when they reached their perilune because an altimeter was an instrument that determined altitude based on changes in atmospheric pressure and the Moon has no atmosphere.

    First Man James R. Hansen 2005

  • Aldrin reported that DOI had come off extremely well, and that it had put Eagle into almost the exact, predetermined perilune from which it was to start its final, powered descent.

    First Man James R. Hansen 2005

  • A standard altimeter could not tell the astronauts when they reached their perilune because an altimeter was an instrument that determined altitude based on changes in atmospheric pressure and the Moon has no atmosphere.

    First Man James R. Hansen 2005

  • Aldrin reported that DOI had come off extremely well, and that it had put Eagle into almost the exact, predetermined perilune from which it was to start its final, powered descent.

    First Man James R. Hansen 2005

  • A standard altimeter could not tell the astronauts when they reached their perilune because an altimeter was an instrument that determined altitude based on changes in atmospheric pressure and the Moon has no atmosphere.

    First Man James R. Hansen 2005

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  • "Aldrin, from the July 31, 1969 Technical Debrief - 'We had two methods of computing altitude: one based on relative motion from the CSM and the other based on angular rate track of objects observed on the ground. We superimposed the two of them on one graph and re-arranged the graph a little bit with some rather last minute (pre-flight) data shuffling to give us something that the two of us could work on at the same time and to give indication of what the altitude and its time history appeared to be. With the communications difficulties that we were experiencing in trying to verify that we had a good lock-on (with Earth) at this point, I had the opportunity to get only about two or three range-rate marks (on the CSM). They appeared to give us a perilune altitude of very close to 50,000 feet, as far as I could interpolate them on the chart.'"

    - 'The First Lunar Landing' transcribed by Eric M. Jones, hq.nasa.gov.

    October 8, 2008