The discovery of Tannhauser Gate effectively aborted much of the Soviet expedition in order to focus on both the Gate and Yggdrasil. The Soviets initially believed that the artifact was produced by inhabitants of Yggdrasil, but a survey of the world revealed no signs of native intelligent life or civilization capable of building something that large.
Tannhauser's purpose was discovered by scientists aboard the Soviet ship Xenu Express, who noticed the artifact responded when probed with radio pulses sent at the right frequency. The Xenu Express managed to establish communication with the artifact's control system and succeeded in activating it. Once active, the artifact generated an immense gravitational force within the inner diameter which stabilized after several minutes into the terminal point of a wormhole.
Tachikoma-19028 (aka "Serge") volunteered to transit the wormhole's event horizon and see where, exactly, it led. Armed with everything the Xenu Express crew could find about the Gate's activation and deactivation protocols, Serge launched from the GCU Yuri Gagarin on October 15, 2013 and entered the wormhole. Six hours later, Serge returned through the event horizon with star sightings and other measurements that allowed the expedition to locate the other end of the wormhole in the Zeta (1) Reticuli system.
The Stargate Network
|Sidebar: Gatemetal, Tannalloy and Interesting Times|
Samples were taken from the first gate, with a view to analyzing and replicating the materials it was made of. Thus far, reproduction is limited to atom-by-atom recreation in particle accelerators with no known way to recreate the full gatemetal mix. It is known that an organisation called The Interesting Times Gang is involved in directing the research surrounding gatemetal. The exact composition of the organisation is a closely guarded secret.
The discovery of the Iconian Gate has made larger amounts available, research has begun towards applications of Gate Metal - starting with energy storage. The first discovered use was in the Mz-23 Judy owned by R. Shinji Ikari, where two cells the size of AA batteries - in shielded cases the size and weight of a car battery filled with charging and discharging electronics - contained the equivelant of 5000kWhours of energy. 
Gatemetal, when used in power generation, is often referred to as tannaloy.
(for reference: Stargates, particularly ones close to Fenspace, get individual names)
|Tannhauser Gate||Delta Pavonis||Zeta (1) Reticuli|
|Night's Door||Zeta (1) Reticuli||Delta Pavonis, ??? (2 others)|
|Iconian Gate||Epsilon Eridani||unknown|
- Either shortly before or shortly after the last bombardment of Yggdrasil.
- This act earned Serge the Order of Lenin by unanimous acclimation upon the expedition's return to Sol.
- Revealed when Prim Snowlight detected Tannhauser Energy Emissions from inside Stellvia's employee hangar
- Presumed to have connected to Tannhauser Gate; the Iconian Gate was destroyed and crashed on the surface of Arcadia through unknown means *mumble* years ago.