Vesta is the the oldest, and as far as I can tell, the leader of the Amazon Quartet. The Quartet are in a Circus which is controlled by Zirconia, who was under the command of Queen Nephrenia.|
How ever the Amazon Quartet was created by NeoQueen Serenity to protect ChibiUsa. Before they were captured (In balls that they now fight with while, they were sleeping.) by Queen Nephrenia, they were known as the Asteroid Senshi. Vesta was named after the asteroid Vesta. Her amazon name is VesVes
Anyway, the Amazon Quartet was to gather Golden Dream Mirrors and Pegasus. Pegasus protected these Mirrors.
VesVes is the animal trainer in the Dead Moon Circus
The Asteroid Senshi are never seen in the anime.