In the mid-24th century, Angosia III was embroiled in the Tarsian War. The planet was able to recover remarkably quickly after the war's end, though the Angosian veterans of the war had difficulty reintegrating into civilian life and were exiled indefinitely to a penal colony on Lunar V. Apparently, no serious effort to reverse the soldier's enhancements was attempted due to a combination of the medical difficulty to do so and the decision of keeping them as a reserve military resource for a possible future need.
In 2366, the Angosian government petitioned for membership in the Federation, and the USS Enterprise-D was dispatched to conduct a follow-up visit. During the visit, Roga Danar escaped his confinement and when the crew of the USS Enterprise-D captured him in space at the request of the Angosian government, the fugitive revealed how he and his fellow soldiers were treated. Captain Jean-Luc Picard attempted to inquire about this revelation, but the Angosian government refused to discuss the matter citing it was a matter of internal security.
Eventually, Danar escaped and the crew of the Enterprise-D attempted to address the matter again, but found the Angosian government's intransigence on the matter frustrating. Eventually, Danar led his fellow veterans from Lunar V in an armed uprising. Despite the earlier stance of the Angosian government on the issue, it with brazen hypocrisy suddenly pleaded for the Starfleet crew to intervene on their behalf. Captain Picard refused, citing that since the government made it clear that this was considered an internal matter previously, Starfleet was not about to step in just because that earlier stance was now inconvenient. Instead, Picard noted that his report is complete and he will be sure to mention the blatant sentient rights violation that the Angosian government had committed with the implication that he would recommend that Angosia's entry into the United Federation of Planets be rejected.
With that, Captain Picard presented a choice to the Angosian government: either attempt to force the insurrectionists back into their confinement or treat them properly as fellow citizens who need proper medical assistance. With that, the petition was at least considered postponed while the Federation offered their assistance to treat the soldiers after the domestic political dispute was resolved. (TNG: "The Hunted")
"ang-GO-sha" was the pronunciation for this planet's name from the script pronunciation guide.
The planet model for Angosia III was first used for Starbase Montgomery planet ("The Icarus Factor"). It was used again for Surata IV ("Shades of Gray"). It was used later for Risa ("Captain's Holiday"), Malcor III ("First Contact"), Starbase 112 planet ("Identity Crisis", Kaelon II ("Half a Life"), Starbase 234 planet ("Redemption II"; "Unification I"), Ruah IV ("The Chase"), Kesprytt III ("Attached"), and Dorvan V ("Journey's End").