Answer: U.S., Japan, China, Canada, and India
Notes: A delegation from the Department of Science and Technology recently visited Mauna Kea to address challenges facing the Thirty Meter Telescope (TMT) project. The TMT, a collaborative effort among the U.S., Japan, China, Canada, and India, is set to be the world's most advanced ground-based observatory. With a 30-meter segmented mirror at its core, the telescope, located on the inactive volcano Mauna Kea in Hawaii, will enable groundbreaking optical, near-infrared, and mid-infrared observations into deep space.
