SOLAR-POWERED STRUCTURAL PRINTING USING IN SITU DESERT SAND
Barren desert landscapes are difficult venues for construction due to low water supply, elevated temperatures, lack of a stable building foundation, and accessibility issues.
A low-cost, self-sustaining, solar-powered system is proposed, which automates large-scale 3D printing of roads and other structures, transforming sand, in situ, to a glassy, opaque and sterile solid as the construction material for roads, dwellings, drift walls etc..
There have been numerous NASA publications in which the regolith of the moon is sintered with microwave (RF) energy. Though the lunar regolith is well suited for this, it requires a significant amount of electrical power.
This approach employs focused solar energy for sintering, requiring much less photovoltaics (PV) to power the electromechanical subsystems exclusively.
Referring to the amateur drawing, the major system components are:
1. A PV array and minimal storage cells for communications, and/or storing additional relocation power. Heliostatic control is optional, likely not necessary for the PV arrays, given sandy sites tend to have ample sunlight.
2. An optionally mobile Printhead platform providing 3-Axes of controlled printhead motion. This must be lightweight and energy efficient. Every mechanism in this system can be pulsed, reducing PV power requirements.
3. A small-gauge "flexible screw conveyor" (a known substance delivery mechanism) feeds the printhead with surrounding sand for sintering. It self-bores into the sand, eliminating complex scoops and conveyors, and only requires one geared motor drive.
4. A heliostatic Fresnel lens assembly provides the sintering heat source. Note that this lens is readily scaled, which accelerates the additive manufacturing process proportionally.
5. A support "flap" can hold the sintering sand from underneath in order to create ceilings without any supporting matrix. It can be angled to regulate the deposition as needed, or out of the way to create foundations and walls.
Note that existing large-scale 3D printing concepts may be retrofitted with this printhead and delivery system.
LOW ELECTRICAL POWER REQUIREMENTS
A PV array and battery subsystem maintains the necessary motion control power, which is significantly lower than for typical construction tools, given the following:
· The actual work output (power over time) is very low, given the slow mobility required, both in terms of printhead motion, as well as raw material delivery rate.
· This is an ideal application for torque-multiplying gear reduction of low output power electric motors.
Thus construction operations are sustained without the need for external fuels to expend nor structural materials to be delivered to the construction site.
Enhancements to deal with safety, locomotion slip, and remote monitoring/guidance of the platform may be added.
A network of these "constructor robots" could be monitored and controlled from a remote central point.
Though this system is only conceptual, it's intuitively readily feasible, introducing no weird science nor "miracle black boxes" into its parts list.
This system can bring comparatively slow, but relentless construction of retaining walls, roads, dwellings and sheltering structures with complex floor plans using near zero materials and labor cost.