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Known alternately as Gray Monday, the Blackout saw unknown perpetrators disable some 75-80 percent of the Hyperpulse Generator network in simultaneous attacks and acts of sabotage, effectively crippling interstellar communications.


On Sunday, 7 August 3132 many HPG stations in the Inner Sphere, the Clan Occupation Zones and the Periphery[1] were taken down by what appeared to be some sort of system-virus which caused the HPG core to overload and burn itself out with little collateral damage. A few HPG stations didn't burn out but suffered different, sometimes bizarre failures which also discount a virus being the cause.[2]

A number of stations (at one point referred to as "more modern ones"[citation needed]) appeared to be immune to whatever affected the rest, but most of these were taken out in a combination of internal attacks of sabotage and swift and efficient military strikes concurrently with the burnout of the others. With the saboteurs either escaping or dying before interrogation, and the surprise of the military assaults, nobody was able to prevent the attacks or learn who was behind the Blackout. The sole piece of identifying information was a strange insignia worn by some of the attackers: a snake coiled around a sword and set against a blood-red disk.[2]

As a result of the Blackout, interstellar communication by and large collapsed, and was reduced to relaying messages via JumpShip in "pony express"-style. The communications blackout had widespread and far reaching ramifications, plunging the Inner Sphere into chaos. Civil unrest grew when it became apparent that the Blackout would not be quick or easy to fix.

Despite the considerable differences between Clan and ComStar HPG protocols and years spent by ComStar's programmers trawling through centuries of kludged-together code updates and patches nothing was found, and even newly manufactured cores showed the exact same symptoms before burning out themselves. ComStar, whose primary reason for existence was the operation and maintenance of the HPG network, threw everything at the problem, but save for restoring the HPG on Wyatt in 3135, and Millungera in 3137, temporary in the last case, nothing has worked, threatening the organization with irrelevancy, bankruptcy and total collapse.

"Black Box" faster-than-light communication was apparently not affected by whatever caused the Blackout, using a fundamentally different working principle.[citation needed]

Clarion Note

Tucker Harwell discovered references to a "Clarion Note" emergency protocol, which was considered by the Word of Blake to be a weapon of mass destruction that would somehow use a Super-HPG to disrupt interstellar communication.[3]

Evidence gathered by Harwell indicated that Devlin Stone's Republic of the Sphere had acquired the technology, and the protocol had been initiated.

"Gray Monday"

It has been speculated[4] that the appellation "Gray Monday" for a date that is actually a Sunday comes from the fact that the full impact of the event was not felt until the following day (Monday, 8 August 3132).

Known attacks

The Vega HPG was one of the first to be attacked by force of arms.[5]

Surviving HPGs

Only a handful of HPG stations throughout the Inner Sphere survived. The HPG's ability to send messages to places up to 50 light years away considerably boosted the strategic importance of the worlds with functional HPGs (a working HPG is required to send messages, but not to receive them as HPGs effectively "jump" radio waves which can be received with regular radio equipment). Known worlds with working HPGs after the Blackout include:


  • In the BattleCorps PDF edition of the novel A Bonfire of Worlds, the date of Gray Monday is given as 1 August (instead of 7 August) which, being a Monday, may originally have been the correct date. However, according to the Line Developer, the date is corrected to 7 August in a proof of the novel which is in line with virtually all other Dark Age era publications (save one novel by Blaine Pardoe).


  1. confirmed by Line Developer Herbert A. Beas II in an official chat on 24 February 2013; see also this article's Talk page
  2. 2.0 2.1 Era Report: 3145, p. 12 "History and Review - The Fall of Darkness - What about the Clans?"
  3. 3.0 3.1 A Bonfire of Worlds, Ch. 10
  4. By Line Developer Herbert A. Beas II; see Bibliography section
  5. A Call to Arms p. 143
  6. A Call to Arms
  7. 7.00 7.01 7.02 7.03 7.04 7.05 7.06 7.07 7.08 7.09 7.10 7.11 7.12 7.13 Era Digest: Dark Age, p. 4 "Functional Republic HPGs as of 01 January 3135"
  8. 8.0 8.1 8.2 8.3 By Temptations and by War
  9. 9.0 9.1 Fire at Will
  10. 10.0 10.1 10.2 10.3 10.4 LinkNet
  11. 11.0 11.1 Flight of the Falcon
  12. Fire at Will; restarted by ComStar during timeframe of novel, but A Bonfire of Worlds mentions that it didn't last
  13. 13.0 13.1 Era Report: 3145, p. 34
  14. A Call to Arms, Fortress Republic
  15. Target of Opportunity
  16. Functional HPG available according to LinkNet articles "Swordsworn, Highlanders Representatives on Towne", dated 01/18/3133; "Jurik: Centauri Lancers Coming to Towne", dated 08/03/3133; Blood of the Isle while LinkNet articles "HPG Working on Achernar?", dated 07/26/3133, and "Message From Achernar", dated 08/02/3133, plus several other INN articles suggest otherwise
  17. A Bonfire of Worlds, The book indicates it's still operating in 3143.