ScienceJuly 14, 2026

microradian

/ˌmaɪkroʊˈreɪdiən/

Definition

A unit of angular measurement equal to one-millionth of a radian, used to quantify extremely precise pointing or directional accuracy.

Etymology

The word is a compound of the Greek prefix 'mikros' (small) and the Latin 'radius' (spoke or ray). It follows the standard scientific convention of using the SI prefix 'micro-' to denote a factor of one-millionth.

In the news

In this article, the term describes the pinpoint precision of NASA's ground-based lasers, which must be aimed with extreme accuracy to hit a distant spacecraft. This level of precision is vital for maintaining a stable optical connection across millions of kilometers of space.

IEEE study presents operational results from NASA’s Deep Space Optical Communications Project

Read the full article ↗

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