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>At this point, NSF has invested approximately $1.1 billion in construction and upgrades, in operational costs, and in research awards to individual scientists,

• gooserock 10y ago
  But it's important to point out that 1) That $1.1 billion was for two facilities 2) LIGO underwent a huge upgrade over the last decade, making the instruments tremendously more sensitive, and the cost of this upgrade is included in there as well. So I suspect that building a third facility with the sensitivity of the two existing facilities would be a much more affordable endeavor. The first time around is always the most expensive.