Sun Scutter - Solar Thermal Bioship

Sun Scutter and Treehome

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Sun Scutter and Treehome Orbiting Lyrdis

The Sun Scutter is a type of low speed interplanetary bioship powered by a solar thermal rocket. These ships are small and usually only carry 1-3 human-size bionts. Sun Scutters are common in systems that favor biotechnology such as those in the Zoific Biopolity, however the basic design is also popular with Genetekkers and hobbyists due to its simplicity. Each ship is grown from a specialized seed which is capable of germinating in a variety of environs, from Earth-like worlds to airless planetoids. No two Scutters are exactly alike due to their organic nature and the fact that they are often grown using resources that are available in the local environment.


Sun Scutter seeds are semi-organic pods about 2 meters tall and weigh around 200 kilograms each. The outer shell of the seed can withstand vacuum, pressures of up to 80 atmospheres, and both freezing and boiling temperatures without damage. Each seed contains a bionano processor, a supply of feedstock, synsect caches, a smart membrane parachute, and a deployable solar array. Each seed contains a small set of hypergolic thrusters for basic course corrections during descent onto a planet or asteroid. The exact time frame and details of the ship's construction and orbital insertion depend on the available resources and solar irradiance. The following is an outline for the creation and launch of a Sun Scutter on a terrestrial world with a gravity of 1 g.

  • Seeds are usually dropped from orbit by a Scutter that is undergoing its reproductive cycle. However if none are available, a Scutter pod can be easily created using a bioforge and implanted manually. On worlds with atmospheres, the parachute slows the descent. If there is insufficient atmosphere for the parachute, the thrusters can be used instead.
  • The seed deploys sensory clusters that detect the environmental conditions and adapt the biology of the base organism in order to ensure survival. There is not a true AI but a simple library of biotemplates that proliferate in the proper conditions. Once the proper phenotype is fully devolved the outer shell decays and falls away.
  • The solar array expands along the ground in order to power the growth of the complex. If there is insufficient sunlight, banks of lithovoric bioreactors, thermophilic organism accumulator ponds, or other similar structures will grow in order to provide energy for the developing bio-complex.
  • Synsects and a network of resource gathering roots similar to a fungal rhizome network begin to collect needed materials and concentrate them in strategic areas.
  • Numerous bulbous semi-subterranean structures grow around the area, collecting and concentrating water and other volatiles from the network.
  • Treelike organisms, often called rocket trees, start to grow around the area. They will eventually transport materials into orbit for creation of a Sun Scutter.
  • Once the rocket trees are completed, expansion of the mining infrastructure slows and eventually halts. Energy from the solar collector is used to create reservoirs of hydrogen, oxygen, and ammonia from stored water and collected materials. The rocket trees fill with hydrogen and oxygen for fuel. Once the trees are fueled, they fill with materials needed to create the Sun Scutter, primarily ammonia, the main reaction mass for a Sun Scutter.
  • The original seed by this time has developed into the largest rocket tree, which contains the living quarters of the Sun Scutter. This tree lifts off first, followed by all of the smaller rocket trees, which soon launch en masse. Most of the lesser trees will not survive the journey into space, especially if this is a first generation Sun Scutter/rocket tree. However the rocket trees that make it to orbit will be the phenotypes most fit for launch off of this particular world. If the Scutter drops more pods on the same planet or at a similar location, the process will be much more rapid and less wasteful.
  • The entire group of surviving rocket trees rendezvous in orbit and fuse into a capsule/egg which absorbs the fuel and materials carried by each tree. After a period of time the capsule shell falls away, and a Sun Scutter is born.


Located in the center of the ship are the habitat areas. The habitat can accommodate 1-3 near-baseline human bionts comfortably and is equipped with a smart matter interior capable of providing any furniture or decor the passengers wish, from an underwater reef to a miniature forest complete with small animals. Several interior nodes can act as a xylem material which can express various kinds of food and drink. The habitat is typically not spun for artificial gravity. Bionts are able to enter several pods located in the center of the habitat in order to enter nanostasis and access the internal virch during a long journey.

Fuel and Defenses

A Sun Scutter is dominated by the bulbous fuel pod at the front. This pod contains the ammonia reaction mass for the solar thermal rocket. It also contains water and SiCHON feedstock for ship life support and the fabrication systems. The low speed of the craft requires only a simple navigational shield of layered ablative adamant and ammonia ice wrapped in spider silk. The ship is capable of partially regenerating the shield if there is enough ammonia and feedstock available. The habitation module contains heavy metals and reflective ceramics such as tungsten for passive radiation protection.

Power and Propulsion

A Sun Scutter is propelled by solar thermal rocket. The native system provides low thrust but is very efficient. Three to four semi-organic smart membrane reflectors about 200 meters across concentrate sunlight onto the rear fuel chamber of the rocket. The reflectors are capable of re-configuring in order to focus the light onto the main thermal chamber regardless of the direction of the sun. This superheats the ammonia reaction mass which is expelled out the rear of the rocket nozzle. Biotech thermocouples provide energy for the rest of the ship's biological systems. Superconducting lines connect the thermocouple generator with the ship's other organs.

Sun Scutters are also able to operate in a laser driven mode, if required. Using a high powered laser focused onto the its reflectors, the ship can operate in areas far from the local star. When the ship is not under acceleration, the reflectors can act as solar arrays for passive energy collection.

Sensors and Communications

The front of the Sun Scutter contains the primary sensor array. A combination of radar and lidar systems provide active sensing, while adaptive 60cm telescopes provide passive long range sensing across the visible and infrared spectrum.

The large reflectors for the propulsion system can also act as multiband radio antennae and also contain chromatophores which work in tandem with the telescope array to allow short range, low bandwidth optical communication. This system is usually used by Scutters to communicate with each other. Scutter occupants will generally make use of other, higher bandwidth communication systems while the ship is having a "chat" with one of its kin. Lastly a small tower located next to the habitat module contains secondary bio-radio transceivers as well as a monocular optical transceiver.

Symbiotic Organism: Scutterhome

After the launch of its primary payload of a single Sun Scutter, the biocomplex does not stop production. Rather production shifts in order to produce a different, but related, space faring organism. This is a biomechanical construct known as a Scutterhome. The Scutterhome is an organic satellite that serves as the keystone for a system's population of Sun Scutters and similar bioships. It uses solar mirrors in to power several long range laser systems in order to provide energy for Sun Scutters moving away from a system's primary. Rocket trees constantly journey to Scutterhomes and serve as raw material for the organism and therefore other Sun Scutters.

The Scutterhome is shaped like a roughly spherical tree, similar to an orwood, but with 6-8 large branches about 5 kilometers long. The branches are covered with solar collection sails that provide energy for the laser system and the Scutterhome itself. At the terminus of each major branch is an ovoid laser complex capable of turning through approximately 180 degrees. Each pod is equipped with a ring of multifaceted laser communication arrays and high powered bioradios. This system allows each pod to track and provide laser energy for a different Sun Scutter.

Rocket trees strong enough to reach a Scutterhome will be absorbed after being "tested". This testing is to ensure that the rocket tree has enough desirable material in its primary holding pod. Rocket trees that are too small, appear damaged, or do not contain the right feedstock will be rejected by the Scutterhome. Only when the Scutterhome senses a worthy organism will it allow the rocket tree to fuse into its structure. In exchange, the rocket tree has its genetic material incorporated into a new Sun Scutter pod. The Scutterhome gets materials needed to survive, while the rocket tree has its genes propagated.

The final phase of the lifecycle of the Sun Scutter ecosystem is the growth of pods to be transported into another location for planting by a Sun Scutter.

Scutterhomes that are harboring fertile pods will attract Sun Scutters with omni directional radio signals - although Sun Scutters already carrying pods are immune to the broadcasts. When they reach a Scutterhome, each attracted Sun Scutter will feed off of fruiting bodies that contain large amounts ammonia, water, and organic feedstock; these fruits also contain a fertilized pod.

As it feeds, the Scutterhome's fertile pod is transferred into the Sun Scutter. Rather than being consumed, the pod integrates itself into a section of the protected habitat section and splices into the Sun Scutter's communication organs. The pod emits signals that coordinate with the Scutterhome, allowing the laser complexes to track the Sun Scutter's reflector arrays. In this way the Scutterhome, Sun Scutters, and the rocket tree progenitors, ensure their propagation across a system.
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Development Notes
Text by Rhea47
Initially published on 26 February 2018.