|Affiliation:||Starfleet Space Cadet Corps|
|Stationed:||USS Dauntless Fleet Space Cadet Corps Unit|
|Rank:||FSC 2nd Class|
|Father:||Peter J. Koester|
Gem Koester was born aboard Starbase Pennsylvania to Lieutenant Peter J. Koester and his wife Mickey in September 2369. Her parents divorced several years later, with Peter Koester gaining custody of the young girl when his ex-wife moved on. When Koester was assigned to Starfleet's Preliminary Survey Program and placed in command of the Gamma Quadrant survey vessel USS Hudson (NCC-72075), he placed his daughter in the care of his own parents on Earth.
In 2372, Captain Koester was assigned command of the Intrepid class starship USS Dauntless (NCC-74658). Shortly after assuming command, the Captain sent for his young daughter, who moved onto the starship with her father.
In 2374, as hostilities opened between the Federation and the Cardassian/Dominion alliance, Captain Koester sent his daughter back to live with his parents, a retired Starfleet admiral and his wife, on Earth, where she remained until the end of hostilities in late 2375. She returned to live with her father aboard the new starship Dauntless (NCC-75310).
In early 2377, Commodore Koester was awarded the post of Presidential Aide-de-Camp and Commanding Officer of Starfleet-One and promoted to Admiral. Young Gem Koester moved with her father aboard the USS Sagan until Admiral Koester resigned his Starfleet commission in 2378. She moved to Tycho City, Luna with her father.
In 2380, Peter Koester petitioned the Federation Council for reinstatement of his commission on the condition he return as a captain and in command of a starship. In June 2380 Koester was assigned command of the Dauntless once again. Shortly after returning to the Sovereign class starship, the Captain enrolled his pre-teen daughter in the Starfleet Space Cadet Corps program, in part to provide the girl with an activity aboard the starship and keep her away from excessive holovid and holodeck use. While reluctant to participate at first, Gem has become deeply involved in the Cadet Corps, rising in rank to Lead Cadet for the Dauntless unit and taking opportunities to participate in away missions and to learn to be a pilot on several of the starship's auxiliary craft, most notably the Captain's Yacht.
Fleet Space Cadet Gem Koester's first real away team mission came in late 2380, when the Dauntless received a garbled communique' from former Command Master Chief Pono R. Kyman, who had settled among the Ba'ku in the Brier Patch. Upon arrival in the Ba'ku village, the away team which included Gem realized the planet was once again under attack by Son'a forces intent on driving the Ba'ku off the planet. While Gem was hidden among the village children, the rest of the away team conducted guerrilla actions against the invading Son'a forces until the Dauntless returned with a Starfleet armada.
Later that same year, Cadet Gem Koester and three fellow Fleet Space Cadets were on a planetary survey aboard the science vessel Akademik Sechenov when the vessel suffered severe problems with its propulsion systems. The Sechenovs captain decided to issue a general distress call and evacuate all unnecessary personnel from his ship. The first vessel to respond was the IKS qul'maS, under the command of Captain Kargoth, who agreed to transport the four human Fleet Cadets back to the Dauntless at starbase Deep Space 9. En route to the Bajor Sector, the qul'maS fell under attack by a trio of Tholian spinner class vessels. Overpowering the Neg'Vahr class battle cruiser, it appeared the ship would be destroyed in the Tholian's web until a suggestion by Cadet Koester, to simply abandon the battle and warp away, not only allowed the qul'maS to escape, but destroy the Tholian vessels by overloading their web spinners as well. For her bravery and resourcefulness during battle, Gem was adopted into the House of Koloth by Captain Kargoth. Since that day, she often wears a Klingon baldric sash with the emblems of the House of Koloth on her cadet dress uniform.
In mid-2381, while Starfleet Academy class of '82 was aboard the Dauntless, Gem Koester and four of her fellow Fleet Cadets participated in another away mission with twelve of the Academy midshipmen to survey the surface of what was believed to be an uninhabited class-M planet designated Temeklia IV. However, due to atmospheric ion interference, the shuttlecraft September 11 lost power in the planet's stratosphere. Quick actions on the part of Cadet Koester, based on knowledge her father had taught her about shuttlecraft systems, re-routed power allowing the shuttle to land hard but survivably on the planet's surface.