Drive Sails
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Drive Sails
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During the period 2400- 2600 a number of third singularity transapients began to develop a new form of reactionless drive. . The breakthrough demonstration is usually attributed to Hayleah Seabhac-Li of New L4 Translabs in 2570, but it mainly built on much previous work in the Sol System and Tau Ceti. Drive Sails use a combination of advanced techniques, all based upon advances in programmable matter and photoelectric effects. It is often forgotten that both electrons and photons are true elementary particles: Both are direct manifestations of strings, and they have near perfect energy conservation in their interactions. Drive Sails have three modes of operation, simple reflective lightsail, ramscoop with microwave photon drive, and selective photoelectric absorption/emission of ambient photons. To sustain acceleration the sheets have to be fed energy externally to retain their surface configuration, making them effectively solid state electricity-to-force converters.
In the early days many expected the sheets to enable "antigravity",
but they proved somewhat disappointing. They did not work inside an
atmosphere since the local matter disrupted their function, and in
order to get a decent acceleration a very large sheet was needed. It
mainly became used for interplanetary and interstellar spaceships,
where it had many advantages over reaction-based drives. Even for the
ships a problem was how to make the sails light and large enough at a
competitive price. They did not need reaction mass, but could not
compete in acceleration with the antimatter
and conversion
drive ships.
Drive sails are at their very most simple used as plain light sails,
often with laser boosting or with mass streams shot by spacetime
catapults. (Deepers make a good exchange providing mass streams and
lasers in this fashion to customers in more of a hurry than they are.
Drivesails are also usable as ramscoops, and have many miniaturized
matter furnaces scattered across their surface. Collected matter is
burned in the furnaces and the energy is used to power the rams and
control the programmable matter. In this mode, the programmable matter
is able to emit photons across the entire surface area of the drive
sail. While the power level per square meter is low, since Drive Sails
are often measured in light seconds the total power is very large. An
even more advanced drive mechanism involves selective
transmissivity/absorption/emissivity of ambient photons. Space is
filled with photons, and the programmable matter of a Drive Sail can
gain appreciable acceleration by absorbing photons on one side, moving
the excited electrons from that absorption to the other side, and
emitting the photons from that side. Using this technique, a Drive Sail
can even gain motive force from the Cosmic Background Radiation, which
is ubiquitous. Compared to conversion drive ships and Pitch
Drives,
Drive Sails are considerably slower and more difficult to maneuver in
tight quarters, but if enough energy is available can eventually reach
0.95c, one of the fastest designs available if you have the patience
for it.
Drive sail ships were used extensively in the Inner Sphere by the minor powers until the Displacement drive was developed. It was much more efficient, enabled far greater accelerations and did not have the sensitive sails to worry about. However, drive sail technology was given to various of the lower toposophic orders, and over the subsequent millennia have retained their popularity among many middletech societies. Drive sails are also possessed and used by many Backgrounders and other external groups. They found that the low-acceleration, mass conserving and stealthy sails were just what they needed, and quietly acquired the technology. Over a span of several millennial they further developed it on their own, perfecting it for their purposes. Instead of having to rely on expensive ultratech manufacturing plants they developed self-contained tradeable ultratech seeds which can grow workable sails from feedstock without outside supervision. These ultratech seeds, typically the size of a small car, can also produce dedicated transapient control systems to control the drive, and repair systems for the sails despite particle impacts and solar winds.
The largest improvement on the old backgrounder design is the Emple-Dokcetic ultratech sails (see image above). They employ a technique similar to their radiation shields: by keeping metallic hydrogen suspended on a particle beam framework they create a near-perfect flat surface. By oscillating the controller fields they create drive patterning. The result is extremely light-weight, disposable sails (when the beams are shut off the sail just dissolves into hydrogen) that can be made into extremely large sails. The only drawback is to keep them stiff enough; this is usually done by employing force-transfer particle beams and micromachinery.
In the current era drive sails are used surprisingly widely, not just by the Backgrounders. They are often regarded as a sign of belonging to a marginal group, and hence are associated with a certain charisma, romantic or fantasist appeal, but that is likely going to change as the Emple-Dokcetic sails arrive fully on the market.
Drive sails are usually visible on close range through bluish Cherenkov radiation from particles passing through their surface layer and into regions of Casimir vacua. However, this is only visible as long as the sail is accelerating and of course not from the side of the sail. By adding stealth patterning, angling sails or approaching along a vector from a bright star a sail-equipped ship can hide quite well as long as it is in the outer system or interstellar space.
Drive sails are sometimes confused with solar sails, but a drive sail is an active engine rather than a passive sail reflecting external directed energy. However, due to their low mass and large area they can act as a solar sail, although this is commonly undesirable and reduces their performance.
