In its decision, NASA states, “No alternate site matches the scientific capability of the W. M. Keck Observatory on Mauna Kea, which hosts the world’s two largest and most powerful telescopes. The W.M. Keck Observatory is found to offer the highest overall scientific potential, as well as the lowest technical and programmatic risk.” Rising above 40 percent of the Earth’s atmosphere, the dry, cloud-free summit of Mauna Kea is used as a platform for the world’s largest observatory for optical, infrared, and submillimeter astronomy. There are currently 13 working telescopes near the summit of Mauna Kea, and four to six Outrigger telescopes are proposed.
NASA retains the option of taking the Outrigger telescopes project to an alternative site in the Canary Islands if, for any reason, the project is unable to proceed at Mauna Kea.
That reason might come from the courts as several lawsuits against the siting of the Outrigger Telescopes are pending.
The Sierra Club, Hawaii Chapter, the Royal Order of Kamehameha and several other plaintiffs are challenging the state Board of Land and Natural Resources permit to construct and operate the telescopes.
In the eyes of many Hawaiians, human constructions on Mauna Kea’s summit constitute a desecration of their deeply held cultural and spiritual beliefs.
The Outrigger Telescopes Project is still being reviewed by the University of Hawaii (UH) Office of Mauna Kea Management, and requires UH approval before it can proceed.