To The Moon!

(Turns out the first ship I want to do isn’t one of the ones anyone asked for. Oh, well.)

SILVERFALL-CLASS LUNAR EXPLORER – BLOCK II

Operated by: Spaceflight Initiative
Type: Early exploration vessel.
Construction: Spaceflight Initiative.

Everyone’s heard of the Silverfall-class explorer, the starship that first carried eldrae from Eliéra to its moons. (A surprisingly large number of them have visited the museum out on Seléne where Silverfall Four — Moondancer — rests in state out on the regolith, where she was flown to her resting place by her original crew, and is kept in flight-ready condition by her many admirers.)

The design discussed here is of the Block II variant of the Silverfall-class, which incorporates the modifications made to improve performance and livability after studies performed on Silverfall Zero and Silverfall One, and whose two examples can be considered representative of the class, including as they do the actual craft, Moondancer, which made the first landing on Seléne; later design revisions included a number of specialized variants, but made no further changes to the basic design.

Length: 42.2 m, of which:

• Mission module: 12.2 m.
• Engineering frame: 18 m (overlaps with propulsion module)
• Propulsion module: 12 m
• Shock absorbers and pusher/ground plate: 12 m

Beam: 12 m (mission and propulsion module); 22m (widest point)
Mass (fueled): 616,200 kg

Gravity-well capable: Yes.
Atmosphere-capable: No.

Personnel: 2 required, as follows:

Flight Commander
Flight Director/Engineer

Accommodates 6 further mission specialists.

Drive: Silverfall-specific fission pulse drive with laser trigger; cold-gas attitude control and landing system.
Fuel: Plutonium coated fuel pellets.
Cruising (sustainable) thrust: 2.4 standard gravities
Delta-v reserve: 16,800 m/s

Drones: Simple automation only.

Sensors:

Star tracker
Inertial tracking platform
Passive EM array
Short-range collision-avoidance and docking radar
Mk. 1 Eyeball

Weapons: None, unless you count the drive.

Other systems:

Thorium pebble-bed power reactor
Omnidirectional radio transceiver
Communications laser
Whipple shield (habitable area only)
Canned (non-regenerative) life support; CO2 scrubbers
Redundant flight control systems
NaK pumped-loop high-power radiators and maneuvering heat-sinks
NH3 low-power radiators

Small craft: None.

DESCRIPTION

The original Phoenix-class orbiter was once described as an explosion in a girder factory, and its smaller cousin, the Silverfall, maintains much of that look, despite at least some improvements in elegance between the designs. That, and that unlike the Phoenix, the Silverfall was designed as a pure space vessel, intended to be built at and operate from Oculus Station in Eliéra orbit, and to land only on airless Seléne and Elárion.

The layout of the Silverfall-class can be divided into four sections: the upper mission module, the engineering frame which sits atop and wraps around the propulsion module, and the shock absorber/pusher plate section at the bottom.

At the top, the mission module is divided into three tail-lander decks with plenum space in between. The uppermost deck, topped by a blunt cupola and surrounded by the various navigational and communications antennae, contains semicircular bridge and mission management sections, surrounded by the ship’s avionics. From it, an axial passage descends through the next two decks, terminating in a small engineering space (housed in an aft projection) where the mission module connects to the primary thrust truss of the engineering frame. A secondary access tube, normally depressurized, runs down from this passage through the engineering frame.

The second deck houses three pie-segment areas; the ship’s laboratory, workshop, and main stowage area. Opposite the stowage area, between the laboratory and workshop, a secondary airlock provides maintenance access while in flight to the exterior of the ship (with a ladder down to the upper levels of the engineering frame), and is the main access point when the starship is docked.

(Opposite this airlock, centered on the mission module’s vertical axis, is the gold plaque bearing the Imperial Star and the stylized rocket-and-crescent-moon of the Spaceflight Initiative, with beneath them the various names and logos of the various contributors making the Silverfall mission possible.)

The third, lowermost deck contains the crew quarters, divided into a number of modular pods, along with the galley, central mess, ‘fresher, and a small medical bay.

Six meters below the mission module is the propulsion module, a heavy steel capsule containing the guts of the nuclear-pulse drive that powers the Silverfall. For the most part, however, it is hidden by the engineering frame which wraps around and atop it, a mesh of trusses containing, most notably, the six pellet silos, evenly spaced around the ship, containing the plutonium fuel pellets, and the spherical tanks of cold-gas propellant and life-support supplies.

The lower surface of the engineering frame (along with that of the propulsion module) is the solid sheet of the protective shadow shield, protecting the upper sections of the craft from radiation produced by the pulse drive. The secondary access tube descending from the base of the mission module connects to the primary airlock, located directly above the edge of the shadow shield vertically beneath the secondary airlock, and from which a descent ladder can be lowered once the drive shroud is in place.

At its edges, laser modules extend past the edge of the shield to trigger the explosive coatings of the fuel pellets; just within those edges, sealed slots permit the segmented drive shroud to be lowered after landing, surrounding the mechanics of the shock absorbers and pusher plate, to protect disembarked astronauts from residual drive radiation.