The Henry Lamb Research outpost was the base of a UNSC scientific research expedition to learn about the Ark, both in the interest of scientific advancement and self-preservation from future Halo threats.
The expedition was spurred on by the re-activation of the existing Halo array in 2555 by the Ark's rampant Monitor, Tragic Solitude. A team travelled to the Ark and stopped Tragic Solitude's plan to aggressively mine the Earth for materials to rebuild the Ark, which had been damaged as a result of the battle that ended the Human-Covenant War.
In 2557, a new team travelled through the portal in New Mombasa in their ship Eden Rising to set up base and activate dormant Retriever Sentinels in order to start repairing the Ark. These researchers established an outpost expansion in February of 2558. In October of that year, the portal back to Earth closed, followed shortly thereafter by the arrival of the Banished fleet. The base and it's outlying facilities were all razed by the Banished attack.