| 1970 | Feasibility Studies and early work on laser interferometer gravitational- wave detector | |
| 1979 | National Science Foundation (NSF) funds Caltech and MIT for laser interferometer R&D | |
| 1989 | December |
Construction proposal for LIGO submitted to the NSF
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| 1990 | May |
National Science Board approves LIGO construction proposal
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| 1991 | March |
LIGO project receives 19 site proposals from 17 states |
| LIGO 40-meter interferometer operated with LIGO displacement sensitivity | ||
Fall |
Congress approves first year funding for LIGO | |
| 1992 |
February
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NSF selects LIGO sites: in Hanford, Washington, and Livingston, Louisiana.
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May |
LIGO Cooperative Agreement signed by NSF and Caltech | |
| 1993 | Spring |
Congress funds LIGO for the second year of construction |
Summer |
NSF review panel endorses technical status of LIGO |
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Start of LIGO vacuum system engineering design |
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August |
Contract for beam tube design signed | |
| 1994 | Spring |
Congress funds LIGO for the third year of construction |
July |
Groundbreaking at Hanford site | |
Summer |
Congress funds construction in FY95 | |
October |
Louisiana site land transfer and leasing agreement executed | |
Fall |
NSF approves new cost/schedule management review | |
| 1995 | July |
Groundbreaking at Livingston site |
Fall |
Congress approves FY96 funding for LIGO construction | |
Fall |
Contract for vacuum equipment and for vacuum beam tube fabrication signed | |
| 1996 | Summer |
Contracts for construction of buildings and concrete slab at Hanford signed |
September
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Contract for construction of beam tube enclosures at Hanford signed |
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October |
Installation of vacuum beam tubes begins at Hanford site
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December |
Raw glass for mirrors received by LIGO | |
Contract for construction of buildings, concrete slab, and beam tube enclosures at Livingston site signed |
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| 1997 | June |
First polished glass received by LIGO |
July |
LIGO prototype demonstrated “splitting a fringe” at LIGO sensitivity goal | |
August |
Buildings at Hanford accepted and occupied by Caltech | |
| First of four 10-Watt lasers received by LIGO for testing | ||
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October
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Installation of vacuum beam tubes begins at Livingston site | |
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December
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LIGO receives final shipment of raw glass
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| 1998 | February | All vacuum beam tube modules at Hanford accepted |
| May | First completed mirrors arrive at LIGO | |
| September | 40-Meter interferometer operated with LIGO optical configuration | |
First 10-Watt stabilized laser installed at Hanford |
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Installation of seismic isolation system begins at Hanford
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| October |
Buildings at Livingston accepted and occupied by Caltech |
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| First beam tube module at Hanford is baked to remove excess water and other chemicals | ||
| November | Vacuum system at Hanford accepted by Caltech |
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| All vacuum beam tube modules at Livingston accepted by Caltech | ||
| December | First fully characterized mirror arrives at Hanford
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| 1999 | January |
Vacuum system at Livingston accepted by Caltech
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February |
Installation of seismic isolation system begins at Livingston | |
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April |
Polishing of mirrors complete | |
| May | All beam tube modules at Hanford are baked
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June |
Coating of mirrors complete | |
| September | First vacuum beam tube module at Livingston completes bake |
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| November |
LIGO Inauguration Ceremony |
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| 2000 | May |
Completed installation of interferometer components for Hanford 2-km interferometer |
June |
Completed bake of the beam tube(s) at Livingston | |
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October |
Achieved “first lock” on Hanford 2-km interferometer in power-cycled configuration | |
| 2001 | February |
Earthquake in Washington State disrupts commissioning |
December |
E7 Engineering Run, first coincident operation of all three LIGO interferometers plus GEO600 interferometer in Germany and LSU bar detector | |
| 2002 | August |
First scientific operation of all three interferometers in S1 run operating with GEO600 and TAMA300 (Japan) interferometers |
Fall |
Continued commissioning leading to improved sensitivity
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| 2003 | Feb-April |
Second science run (S2) operating with TAMA300 interferometer |
| Summer | Continued commissioning leading to improved sensitivity | |
| Nov-Dec | Third science run (S3) operating with GEO600 and TAMA300 interferometer | |
| 2004 | Mar - June | Installation of active anti-seismic system at Livingston |
| Upper limits papers using S1 data published in Physical Review | ||
| 2005 | November | Begin year long data run at design sensitivity ("S5") |
| 2005- | Improved upper limits uing data from S2-S4 published | |
| 2006 | November | Open LIGO Science Education Center in Livingston |