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Cosmic Microwave Background Stage 4 (CMB-S4)

A white telescope dish is set in the desert with mountains and a colorful sky in the background.
CMB-S4 site in Chile
Credit: Debra Kellner

Telescope Details



South Pole and the Atacama Desert in Chile


CMB-S4 will be unique in the scale at which technology will be deployed, including the sheer number of detectors — a total of 550,000 — and telescopes and volume of data to be processed. The 21 telescopes will help measure the mass of the neutrino, map the growth of matter clustering over time in the universe, shed new light on mysterious dark matter and dark energy and aid in the study of powerful space phenomena such as gamma-ray bursts.

NIST’s role:

Will provide detector arrays and electronics. 

Significant discoveries:

The cameras are still under construction.

Other interesting facts:

The cameras will use mostly two-color detectors to cover 11 frequency bands. This design enables the removal of contamination such as dust, which has known signatures, from the target signals. 

Supported by:

U.S. Department of Energy and the National Science Foundation


236 members at 93 institutions in 14 countries and 21 U.S. states

Created October 7, 2021, Updated November 3, 2021