Bilskirnir-class ship

"An Asgard mothership. I've heard them described in Jaffa legend."

- Teal'c

The Bilskirnir-class, also known as an Asgard mothership, was a series of spaceships used by the Asgard at the height of their power.

Overview
Bilskirnir-class motherships were the primary type of ship used by Asgard race. They had a distinctive shape with a hammer style front with wings by the side and a grayish hull. The sensors of these ships were quite accurate and capable of detecting movements within the vessel should intruders board the craft. This included a type of thermal sensor which allowed for the detection of warm blooded organisms moving about the ship in case the primary internal sensors were disabled.

They possessed an automated medical system that allowed for the healing of injured crewmen. However, it was possible to tamper with the system which was capable of killing an Asgard in the process. It included at least one medical stasis pod that can be used by the ship's Asgard commander in the event of a dire emergency.

The ship also contained a phase generator which emitted a subspace field which was deflected by certain systems in the ship. This in turn meant that the ship was incapable of tolerating an uncontrolled re-entry into a planet's atmosphere. Bilskirnir-class vessels were powered by a series of four neutrino-ion generators which produced an engine output of a maximum of one billion Earth kilojoules.

Such ships were more than a match for several standard Goa'uld Ha'tak motherships, although warships modified with Ancient technology by Anubis have been known to pose a greater threat.

Defenses
A powerful shield protected the Asgard ships from external threats. This included powerful shockwaves from vessels that detonated some distance away; however the shield was incapable of protecting the vessel from explosions already inside the shield barrier and close to the hull itself.

Internally, the Bilskirnir-class utilized internal dampening fields which activated in the event of an explosion. This prevented the use of explosive devices inside the ship and dampened the impact they had if they were triggered inside the vessel.

The ship also included a form of cloaking which did not distort the appearance of the vessel but rather made it invisible to primitive scanning technology.

Engine system
The Bilskirnir-class had the capability of crossing the galaxy in a matter of minutes and were even capable of crossing the intergalactic void to travel between galaxies. The speed of this was hampered if the vessel was towing another vessel along with it through hyperspace.

Forward propulsion was achieved through the use of two rear thrusters. A specific engine within the vessel allows for re-entry and was known as the deceleration drive.

Transporter array
Like most Asgard vessels, the Bilskirnir-class possessed a number of Asgard transporter arrays located on the ship. These were all aimed in different directions and allowed for maximum coverage. After entering a specific code into a computer terminal, the transporter array activated and the targeted material will be transported to an indicated cargo hold.

The limits of the transporter technology remains unknown, though the Prometheus was capable of transporting an entire skyscraper into orbit. Daedalus-class vessels are capable of at least equal feats. It is obvious that such feats were easily performable on the Bilskirnir-class as well, since it was capable transporting an entire army of Jaffa and three incomplete Goa'uld ships.

The array included an outbound transporter technology allowing for crew to escape the ship and move to external locations such as a planet. In case of Replicator infestation, the ships outbound transporter was destroyed to prevent the Replicators from escaping the ship. It was capable of being pre-programmed by the crew in order to aid others who use the system in the future.

The Asgard were capable of using the transporter array against armies on a planet, dematerializing them and removing them as a threat.

Weapons
They were equipped with a forward firing energy based weapon which served as its primary armament. These were more then capable of dealing with Goa'uld Ha'taks until Anubis began modifying his ships with Ancient technology.

Bridge
The primary control center of the ‘’Bilskirnir’’-class was the bridge. It resembled a large pillar of light with numerous platforms present through which the ship was commanded by the crew. The bridge was also the home of the navigational computer allowing for the alteration of the vessels position.

The Replicators were known to infest the bridge of these ships in order to take control of them and disable the internal sensors, preventing their detection by the crew.

Computer Room
It was possible through the use of the computer terminal to chart the progress of crew inside the vessel and detected hostile threats to the crew. Locations of the ship that were disabled flashed on the screen. It further allowed for magnification to certain areas in order to gain a better view of certain locations of the ship. It also allowed for the manipulation of the transporter array through the use of the stones on the central terminal.

In addition to this, a user in the control room was capable of manipulating the stones to activate the vessels Asgard holography allowing them to appear on a planet and communicate with others. Furthermore, the computer room was capable of being programmed to provide instructions to crew who were not familiar with Asgard technology.

Airlock
The ship contained a number of airlocks allowing for crew to enter or exit the vessel. Internally, the chamber had a doorway which was closed and had a control by the side which resembled Asgard stones.

The top stone controlled the inner door, the middle stone depressurized the chamber and the bottom stone opened the external hatch. A similar set of controls existed on the outside allowing for individuals in space suits to open the hatch and enter the ship.

History
"Ladies and gentlemen, I think this is…Thor's chariot."

- Daniel Jackson

The first sighting of a Bilskirnir-class vessel was on the protected planet of Cimmeria, which had been invaded by the Goa'uld Heru'ur. SG-1 managed to inform the Asgard of the invasion of the planet, a cry for help that was answered by Thor, who made an impressive entrance and used his vessel to easily remove the assembled army's presence; forcing Heru'ur to retreat through the Stargate.

During the Asgard-Replicator war, many Bilskirnir-class ships were infested by Replicators, who took control and turned them against their own creators. A fleet of three such vessels were on a course for the Asgard homeworld, but were destroyed when the prototype of the O'Neill-class self destructed in hyperspace, destroying the ships.

By the time of Anubis' re-emergence, this design was slowly being phased out in favor of the much more powerful O'Neill-class.