Halcyon-class light cruiser
From Halopedia, the Halo wiki
Summary
The UNSC Halcyon-class cruisers were designed by Dr. Robert Mclees in 2510, and served only a short while because their unique hull design was considered too costly and risky to use, as well as being too slow. They were subsequently replaced by the Marathon-Class cruisers. Their only noteworthy design feature was a series of cross bracings and honeycombs; however, these made the ships virtually indestructible. They can be operational after sustaining breaches to all compartments and losing 90% of their armor.
Some, however, were later pulled from long term storage after the Covenant War broke out. According to Covenant computers, the halcyon class cruiser is listed as a 'Human attack ship type C-11'.
