Dyaush Interstellar Colony Ship
Early interstellar colonisation efforts used many different techniques to bridge the enormous gulf of empty space between the Solar System and nearby stars, including fusion pulse drive, catalysed fusion and antimatter/fusion hybrid, while many probes and other craft were propelled to interstellar speeds by a variety of light sails or magsails. All these systems have associated drawbacks and inefficiencies, and all craft travelling at interstellar speeds needed shielding from high speed impact with the interstellar medium.
Many craft were hastily assembled during the Great Expulsion era from 620 a.t. onwards, but these ' backyarder' vessels often failed to reach their destination or did not provide adequate life support for all on board.
By 910 the Dyaush, the first colony ship launched toward Eta Cassiopeia, was a combination of several different technologies, and successfully reached its destination a hundred and ten years later. The Dyaush was fairly typical of the craft launched in the first years of the Federation, and was the first member of a numerous class of similar ships, which were almost all seedships carrying zygotes or DNA data.
Launched from Surya, a vulcanian class asteroid near the Sun, the 2.5km long, pencil thin Dyaush was constructed almost entirely from carbon-fibre reinforced cometary ice. For several years the solar powered terawatts laser banks of the Keralan Power Combine had been creating matter/antimatter pairs in huge amat farms and sorting, combing and storing the antimatter using magnetic fields. Several tonnes of frozen antihydrogen were carried by the Dyaush to catalyse the amat/ fusion reaction drive, with an iron shell surrounding the centrally placed payload, protecting it from gamma radiation.
The payload included thousands of frozen human zygotes. and a collection of synthetic human robots known as Parental Vecs, intended to nurture the new-born humans at the colony. Over time the new-born humans would either displace the synthetic Parentals, or develop a hybrid culture. The limited agricultural genetic library available to the Keralans was also included.
On launch, the Dyaush briefly fired its amat/fusion motors to enter a low energy transfer orbit to Mercury, then executed a slingshot manoeuvre around Venus and Jupiter. Leaving the plane of the solar system using the gravity of that giant planet the ship coasted until it was two million kilometres above the ecliptic, then extended a magnetoplasma sail filled with fine iron particles. A series of particle beams based on various moons of Jupiter (but owned by the Keralan Power Combine) now accelerated the craft by exerting pressure against the extended magsail. As the ship rose away from the solar system, this magnetic field was carefully controlled so that it did not encroach on the sovereign territory of any space colony: eventually the sail expanded to a tenuous one million kilometres in radius by the time the ship left the heliopause and switched it off. The Keralan power masers were used to launch many thousands of interstellar craft in this period and the amat combine became one of the most powerful political players in the Solar System.
The Dyaush now began to accelerate using anti-matter catalysed fusion, with each three hundred kg of hydrogen extracted from the water ice activated by 0.1 kg of amat in the main fusion/amat reaction. This fusion reaction then expelled steam as reaction mass, gradually consuming the icy body of the craft, the steam produced introduced as an outer cooling jacket for the fusion reaction and producing a little more efficiency in the conversion of matter to thrust. Periodically left over oxygen and carbon from the ice and support structure were fused at a higher temperature, and the ship grew shorter until the drive was extinguished at a velocity of 0.2c.
As the craft coasted into interstellar space, its long cylindrical iceshield was eroding from contact with interstellar dust and molecular gas at high speeds. A scanning lidar watched out for larger particles, giving minutes of warning for avoiding action to the unsleeping synthetic human crew. A side effect of the strong laser scan was excitation of much of the interstellar material, allowing a certain amount of deflection by magnetic shields.
At 1.5ly from Eta Cassiopeia the ice shield was nearly eroded, and the secondary motor was revealed, which was now fired to brake the much lighter ship on approach to its destination. As the ship hit the heliopause of Eta Cassiopeia B, an orange K7 dwarf, a magnetoplasma parachute was extended, and a small amount of velocity was also transferred to this star in a reverse slingshot orbit. 50 AU from the B star was the A star, Achird, which the ship approached with reaction drive and parachute as brake.
Using such a sacrificial structure for the construction of the ship allowed the relatively small payload vessel to move around the target system with little requirement for fuel.
Although the Parental Vec seedship strategy did not work quite as intended at Eta Cassiopeiae (Diwali), it was successful elsewhere (as at Uoaguanyu). Many broadly similar ships were built, some using RAIR and Seeded RAIR drives instead of sacrificial ice construction, and often with hundreds or thousands of colonists in Nanostasis, rather than using the Parental strategy employed on the Dyaush. The centuries after the establishment of the First Federation saw several million humans leave Old Sol for the new worlds of what later became the Inner Sphere.
Text by Steve Bowers
Initially published on 05 November 2003.