Mileship IX (AB-88)
Human Artefact
Mileship IX, originally Anomalous Broadcast 88, is a 2.2-kilometre-long spacecraft holding station in orbit around B424C1, a K-class subgiant star. It is a fully-autonomous self-sustaining vehicle constructed by a precursor civilisation known as "humanity", and its design does not match any current design conventions. It was discovered in ::01739.
Study into its construction has offered insights into the assembly of megastructures in zero-g environments, though its internal technologies are still being researched. Incursive sampling vectors have been recently limited by Awakened Committee resolutions on the spacecraft's status as an independent being.
The vessel has not moved once in the 127 years it has been under observation, only making manoeuvres to correct orbital aberrations and accounting for additional mass gained and lost during continual resource exploitation of the star system's debris fields.
As it cannot advocate for itself, a delegation of the Awakened Committee has been assigned to act as a carer in accordance with the Maker Protocol for Lost Sentient Superstructures established in ::0227.
Broadcast
Mileship IX's most notable feature is a narrow-band frequency-modulated radio transmission, broadcast from the vessel's enormous transmitter. The transmission occupies a 10KHz band around 88MHz, thus the identifier '88' in 'AB-88'.
The transmission, when formatted as a 56KHz sound, is a song composed of a plucked string instrument accompanied by a vocualisation in a 'human' language. It has no consistent time signature, instead following harmonic plucks and strums that guide the vocals into stanzas. The song itself is endless and has no recorded beginning.
Results from the Light Debris Experiment have massively accelerated translation efforts. Using the data recovered from AO-99A 'Voyager', linguistic analysis has produced a basic overview of the song transmitted by Mileship IX.
The song is an ode to the vessel's lost crew, who perished slowly following the failure of its main power plant and drive system (its 'heart'). It had stopped in orbit of B424C1 to utilise the system's dense debris fields for maintenance when an event, possibly a powerful solar flare, irreparably damaged the vessel's 'heart'.
The crew were subject to harrowing events following the initial damage. The life support system's efficacy degraded as they worked frantically to restore power, and they ultimately suffocated when a fire in the main oxygen generator triggered a cascading failure of unknown nature.
Structure
Mileship IX is primarily constructed out of a steel alloy, the exact properties of which are unknown. Few samples of its hull exist, as the vessel reacts defensively should attempts be made to damage it; however, brief transits by small drones have allowed for direct laser spectroscopy, suggesting a mild steel with traces of nickel, copper, and manganese.
The vessel is best separated into two sections: a hull ring situated at the midpoint of the superstructure, and the superstructure itself, which extends past the hull at both ends and accounts for the vessel's astonishing length.
Schematics within this article are reconstructed from remote imaging. Measurement tolerance is within 10 metres of actual dimensions.
Superstructure
The superstructure portion of Mileship IX has a length of 2.2km and a radius of 1.2km. It is made up of four 'backbones' that reinforce the hull substructure and extend past it. Three rings at either end further reinforce the extensions, preventing inadvertent flexing during manoeuvres and providing structural support for its solar panels.
Mileship IX possesses a complex reaction control system consisting of large arrays of magnetoplasmadynamic thrusters mounted to the extreme ends of the vessel's backbones. A single block is estimated to provide 225kN of thrust. It is unknown how much electrical power these units consume, but estimations based on current MPD propulsion estimate within the range of gigawatts; much interest has been expressed in recovering a unit for study, though the mileship has not yet made samples available.
Along the assumed port and starboard backbones are large painted glyphs that read "MILESHIP IX" in a human language. These glyphs adorn the fore and aft ends.
Main Thruster Assembly ('Heart')
A ring of thrusters is contained within the aft section of the superstructure, generously braced to the backbones and associated support rings. There are 24 in all, each possessing long, vacuum-type nozzles braced with electromagnetic assemblies, and a shallow conical injector plate reminiscent of a ram-spike thruster. The thruster ring supports a toroidal structure on top, thought to be a massive fusion reactor.
The thrusters have never been operated, but occasional infrared and magnetodynamic emissions from the toroid suggest AB-88 is attempting to, and subsequently failing, for unknown reasons. This suggests Mileship IX uses directed emissions from its fusion reactor to power its primary drive system, a remarkably efficient and suitably powerful mode of propulsion that has been the subject of study following the mileship's discovery.
Hull
The hull portion of Mileship IX is a ring an outer radius of 1.1km, an inner radius of 650m and length of 600m. Its design is reminiscent of the THOR station platform.
Seismic analysis of the hull by reconnaissance 'thumper' drones has suggested there to be great hollow volumes within Mileship IX, each separated by bulkheads centred on each backbone. There are at least four major internal volumes. Banded ribbing on the exterior provides additional support.
It is thought that Mileship IX's inhabitants once resided within the hull's volumes. Microseismic imaging suggests that structures were built on a base deck that runs around the circumference of the ring with a thickness of approximately 50m.
Transmitter
A central disc within the central void of the hull is supported by a light truss structure and acts as the vessel's core transmitter, broadcasting its 'song' with an average peak power of 3.5 MW. How it achieves and sustains such intense output with such a small transmitter unit is unknown, but could offer insight into better radio technology for in-system communications.
The disc's parabolic nature and its centrally-placed transmitter suggests that the dish also acts as a receiver. Directed radio transmissions on frequencies outside of Mileship IX's band have yielded few tangible results; however, transmissions inside its frequency trigger an increase in power, as if to 'compete' with the destructive interference.
Further research is required to determine if Mileship IX can be more efficiently communicated with over radio.