Around 8,000 years ago, it is believed that the Ancients arrived on the planet and built a massive structure on the planet. This structure, known as the Temple, was later reconstructed by the Hammer of Light which used the Temple as its headquarters. The eventual fate of the Temple is not known. Altair is one of several planets on which Ancient artifacts are found.
Not much is known of Altair V's climate or terrain, though it is described as at least habitable by Vasudans. Its proximity to Vasuda Prime as well as its status as habitable probably means it was heavily colonized by the Vasudans at some point due to the inhospitable conditions of their homeworld. However, since Altair was not completely explored at the time of the Great War, it was probably not colonized until the Reconstruction era, possibly as a replacement for the devastated Vasudan homeworld.
In the intelligence animations, a heavily forested planet located in Altair is highlighted, which also contains Ancient remnants, which may or may not be Altair V (this planet, however, is depicted as being the first planet from the Altair star, not the fifth). Additionally, in the FreeSpace 1 mission briefings, a group of Vasudan scientists made planet fall on a previously uncharted planet, Altair IV. Ancient ruins were also found on this world. This gives rise to the possibility of several habitable planets in the Altair system, at least three of which contain Ancient ruins. This is a possible canon inconsistency.
Little else is known about the planet except what is mentioned in the FreeSpace Reference Bible. Given that it is not mentioned in any other source, its canonicity is questionable. It may have been retconned and replaced with Altair Prime (as shown in the intelligence animation) or Altair IV (as mentioned in the game itself).