In collaboration with the Jet Propulsion Laboratory, physicists Andrew Lange, Jamie Bock, Brian Keating, and William Holzapfel began the construction of the BICEP1 telescope which deployed to the Amundsen-Scott South Pole Station in 2005 for a three-season observing run.

[12] Immediately after deployment of BICEP1, the team, which now included Caltech postdoctoral fellows John Kovac and Chao-Lin Kuo, among others, began work on BICEP2.

The telescope remained the same, but new detectors were inserted into BICEP2 using a completely different technology: a printed circuit board on the focal plane that could filter, process, image, and measure radiation from the cosmic microwave background.

BICEP2 was deployed to the South Pole in 2009 to begin its three-season observing run which yielded the detection of B-mode polarization in the cosmic microwave background.

[15][16] Reports stated in March 2014 that BICEP2 had detected B-modes from gravitational waves in the early universe (called primordial gravitational waves), a result reported by the four co-principal investigators of BICEP2: John M. Kovac of the Center for Astrophysics | Harvard & Smithsonian; Chao-Lin Kuo of Stanford University; Jamie Bock of the California Institute of Technology; and Clem Pryke of the University of Minnesota.

[15] In part because the large value of the tensor to scalar ratio, which contradicts limits from the Planck data,[20] this is considered the most likely explanation for the detected signal by many scientists.

[22][23] On January 30, 2015, a joint analysis of BICEP2 and Planck data was published and the European Space Agency announced that the signal can be entirely attributed to dust in the Milky Way.

[25] A March 2015 publication in Physical Review Letters set a limit on the tensor-to-scalar ratio of r < 0.12.

[6] The Keck Array consists of five polarimeters, each very similar to the BICEP2 design, but using a pulse tube refrigerator rather than a large liquid helium cryogenic storage dewar.

[7] In October 2018, the first results from the Keck Array (combined with BICEP2 data) were announced, using observations up to and including the 2015 season.

One consequence of the large focal plane is a larger 28° field of view,[33] which will necessarily mean scanning some foreground-contaminated portions of the sky.

[37][38] According to the project website: "BICEP Array will measure the polarized sky in five frequency bands to reach an ultimate sensitivity to the amplitude of IGW [inflationary gravitational waves] of σ(r) < 0.005" and "This measurement will be a definitive test of slow-roll models of inflation, which generally predict a gravitational-wave signal above approximately 0.01.