Institutional timeline
1974 → present
A sparse chronology. Click an entry for related documents, technologies, and stations. The interesting years are often the ones that refuse to conclude.
1974 Founding Memorandum
The Continuity Office is established. The Reversibility condition is attached to the endowment over the board's reluctance. MERIDIAN begins as the vault of record.
1981 Observation 7A
A 1,270-second periodicity appears in clock-comparison residuals at a temporary northern emplacement that will later become Station LOWFIELD. No explanation is established.
1986 LOWFIELD commissioned
Formal commissioning of the northern station, years after first occupation. Radio quiet is chosen over access. The earlier 1981 record remains outside the station instrument log.
1991 Institution renamed SENTINEL
The Continuity Office takes the public name SENTINEL Research Group. The charter does not change. Observatory ASHEN is brought online the same year.
1993 ARGENT incident
Nineteen hours during which the primary site believed it knew the time and did not. No data was lost in the moment; months of prior data became unusable in review.
1998 Sentinel Grid
The institution's private compute and storage fabric enters service on the assumption that any site can vanish without warning for an unbounded period.
2006 Argus
Internal instrument-integrity monitoring is formalised. Argus watches SENTINEL's own sensors for confident falsehood, not people or public spaces.
2009 Protocol Sigma
The Disclosure Board publishes its decision procedure for uncertainty. Restraint and release both require a dated justification.
2011 Atlas Engine
The analysis platform that refuses unsourced synthesis enters institutional use. For eighteen months it is widely considered useless. The refusal stays.
2013 Open Instrument
Internal tools without strategic sensitivity begin to be released under permissive licences — only while still in use internally.
2016 Project Polaris
Distributed timing reference for long disconnection. Experiment Delta demonstrates that holdover can fail without looking like failure.
2020 Nexus
Secure interchange becomes the single controlled boundary for partner exchange and Archive publication. Withdrawal of a release is itself a record.
2024 Convergent independent results
Four groups with no contact reach related unusual results within nineteen months. The Board publishes a careful note and does not claim a cause.
2024 Period-1270 cross-index filed
SEN-24-128 binds Observation 7A, Recovered Signal 14, Tape Series M, and CASE-1270 under one public index term without claiming a mechanism.
2025 Current sealed entry
SEN-25-002 is listed as SEALED: existence acknowledged, contents withheld. The gap is part of the public record.