The Allied Worlds Survey Ship Zheng He is wormhole-going long-range fusion ship. Together with sister ship Marco Polo, the Zheng He was designed to explore space beyond that of the Allied Worlds.

History

The Zheng He is a refit of Buraq, the lead ship of a class high-performance spacecraft used to respond (relatively) quickly to distant emergencies in Allied systems. Compared to the Buraq, the Zheng He has had its armor reduced and weapons eliminated in favor of additional supplies, fuel, and landing craft. (It should be noted that the Buraq class was not intended to fight purpose-built warships at technological parity, and as such would not be competitive with them in open combat. This goes double for the Zheng He and Marco Polo which do not even have anti-ship weapons.)

Propulsion

To accommodate their long-range rapid-response role, the Buraq-class patrol spacecraft use deuterium/helium-3 fusion. (Most ships use deuterium/deuterium fusion) Helium-3 is considered a strategic resource by the AW; the same resolution of tensions in the Dirac system that has enabled the reexploration of connected space beyond it also makes the AW's Helium-3 extraction and production capacity more available for other purposes.

The drive of the Zheng He is a highly advanced fusion reactor with a direct electrical conversion system to supply both its own confinement magnets and other electrical service needs. The versatile drive can trade off efficiency and thrust to accommodate a variety of missions. Using only the fusion plasma as propellant, it can attain exhaust velocities in excess of 8% of lightspeed (20 000+ km/s). Alternately, thrust up to 0.1g can be realized with the use of supplementary water propellant. The Zheng He is outfitted with equipment for in situ propellant extraction and refining; combined with its high energy-density fuel (D/He3 fusion), this gives it outstanding effective range and independence from infrastructure.

Mission

The Zheng He is intended to establish peaceful contact with the wormhole-connected worlds beyond the Dirac system, hitherto impassable to the Allied Worlds and separating them from the rest of connected space. Of course, the mission is fantastically expensive, and the AW are counting on the Zheng He and Marco Polo not only to establish diplomatic relations and collect geographical information, but to encourage the development of economically viable trade, identifying high-value resources of interest to the newly contacted planets or to the AW. Where appropriate to local techno-industrial development, the construction of infrastructure facilities to support interstellar trade will be encouraged.

The cargo space of the ships is being loaded with high-value objects believed to likely be of interest. They can be traded or dispensed as gifts to secure the cooperation of the civilizations visited. The ships' computer networks are loaded with a great variety of scientific, technical and cultural publications, as well as manufacturing instructions and programs, to be exchanged for their counterparts from other technologically advanced cultures, or for correspondingly precious material goods.

The ships will also have a scientific mission, to investigate the effects and scope of cultural divergence that took place in the long centuries since the fall of the Empire. Much of the centrifuge space added in the refits of the survey ships has been to accommodate scientific facilities and personnel, and expectations are accordingly high. A particular focus has been placed on the onboard medical and quarantine facilities, in light of the risks of encountering unusual pathogens. The advanced medical facilities will allow artificial hibernation to be applied in non-emergency situations to personnel who would not normally be considered medically qualified for hibernation.

The Zheng He is unarmed except for a pair of point-defense lasers sufficient to protect it from small space debris or primitive weapons. Its powerful fusion drive, though not optimized for the purpose, is necessarily quite deadly if pointed in the direction of a relatively nearby enemy structure, but this is a basically unavoidable property of any high-performance propulsion system.

The AW strongly wishes the expedition not to start any wars. It is thought that the unarmed ship will seem less threatening to advanced civilizations that might be encountered, reducing the odds of a hostile reaction.

Small arms are stored onboard for the defense of landing parties in primitive conditions (e.g. wild planets or those where the existing civilizations may not have a well-developed respect for the customs of diplomacy.)

Layout

There are two habitat centrifuges contained within the huge main pressurized compartment, which contain most of the living and working space. Having the centrifuges within pressurized space simplifies their design greatly, and the large pressurized volume, realized as an inflatable structure, provides a good atmospheric buffer capacity in case of fire or leaks. A garden and freefall recreation area are contained in the rest of the pressurized compartment, with the exterior configuration of the slowly-rotating centrifuges designed to avoid the possibility of catastrophic trauma caused by colliding with them in freefall. Other pressurized sections run axially on the ship. At the forward end is an observatory copula. Aft of this is the hangar bay pressurized staging and airlock area, a central passageway, a command center and radiation shelter, the pressurized engineering spaces, and the engineering airlock opening into unpressurised machinery spaces.

Each of the habitat centrifuges has an outer (lower) deck of radius 32m, and an inner (upper) deck of radius 29m. Width 5m. Ceilings ~ 2.2m

The forward centrifuge contains mostly facilities related to the ship's exploratory mission.

The after centrifuge contains mostly facilities related to the operation of the ship, though it has been refitted from its original condition.