[logo for Project Solaris by Nembo Buldrini]
Energy from the Sun
When it comes to space exploration, energy supplying is surely one of the most limiting issues. Our Sun is the largest energy source in our solar system and probably will stay unrivaled for the next several centuries. The amount of power it radiates is daunting, and being able to manage even a fraction of it would enable a huge step forward in space exploration and exploitation.
[Image Credit: Nembo Buldrini]
All we Need is a Large Mirror…
Other forms of energy production methods are expected to be developed over the next decades, the most anticipated of them being controlled nuclear fusion. However, the Sun is already producing about 1026 J every second. Being able to manage a given amount of this power means finding a way to direct and concentrate light radiation. In other words, we need a large mirror or refractor: let’s call it, in general, a light deflector. Several space mirror concepts have been designed and tested in space: all of them rely on the use of a metalized continuous surface kept in place by scaffolding material structures (for example: Znamya 2). While the design and deployment of this kind of system are relatively straightforward for small structures, it becomes to an issue when the dimensions are too large.
… Or Several Small Ones!
The main intent of Project Solaris is to address this issue. The idea is to use a distributed system composed of a multitude of small light deflecting units (cm-sized to µm-sized). These units will be uniformly scattered over a disc shaped plane and kept in place using different techniques (radiation pressure and/or electric fields and/or magnetic fields, or other methods). Easy deployment, fault tolerance and live scalability are some of the advantages that this system could provide.
[Image Credit: Nembo Buldrini]
Asteroid Course Deflection And Asteroid Mining
Large distributed light deflectors can be used for correcting the orbit of asteroids on collision course with Earth: the solar radiation can be focused on a spot, where the asteroid material will be vaporized and ejected into space, pushing on the asteroid by reaction effect.
In the same way, asteroid mining can be accomplished. The ejected material can be condensed on suitable orbiting collectors. The vaporization process, modulated by varying the spot temperature, can also serve as a first refining step.
[Image Credit: The Planetary Society]
Antimatter Factories
An additional exciting possibility that the availability of high energy densities would enable, is the mass production of the material with the highest known energy storage density, that is antimatter. Antimatter factories could be setup as close as possible to the Sun, and would be able to deliver antimatter for powering space vehicles and other space appliances.
[Image Credit: Adrian Mann]
Light And… Shadow!
Other than using a large deflector for directing light towards a point, one can use it to deflect light away from a point, thus creating a shadow. This implementation can be very useful for several futuristic concepts, like large space habitats, planet terraforming and climate modulation.
[Image Credit: NASA]
Fast Space Travel
The pressure of light radiation can be used to propel a spacecraft equipped with a light sail, which would reflect the solar light concentrated by a large distributed deflector. Because the spacecraft will not need to carry the propellant and the energy source, it can be made very light and high accelerations can be possible, thus allowing fast traveling between solar system locations. Alternatively, depending on the method used to keep the mirror units in place, a distributed deflector can be part of the spacecraft, the mirror units providing the momentum directly to the vehicle.
Going Interstellar!
Beaming power to large distances, as it would be needed in the case of supplying a spacecraft for propulsion, would require converting the solar light into laser light. Solar pumped laser would then be the natural choice. However, in order to reach “interstellar” distances, additional relay optics will be necessary, the structure of which can also be based on the distributed deflector concept. An example of this arrangement is the interstellar lightsail concept made famous by Robert Forward. The power collected by a 28 km radius deflector placed at 1/10 of the distance of Mercury from the Sun would be about 1PW, enough, considering also the solar light-to-laser conversion efficiency, to enable fast interstellar travel.
[Image Credit: Adrian Mann]
Not Only For Energy: Distributed Scalable Space Telescopes and Antennas
Large space distributed mirrors can work as the primary optical component of a telescope, provided high precision in controlling the position/tilt of the mirror units is achieved. Baselines of several hundred meters and beyond will be capable of bringing the newly discovered worlds and the universe closer to us.
[Image Credit: Nembo Buldrini]
Project Solaris Main Steps
The main steps of Project Solaris can be briefly described as following:
1. Brainstorming with definition and selection of the best sounding distributed light deflector concept(s)
2. In-depth study of the selected concept(s), which will include:
a. Simulation of self-organizing unit swarms in space, using different actuation approaches. For example:
• EM interactions
• Radiation pressure
• Interaction with fast particles (ions)
b. Development of algorithms for controlling attitude and position of the single mirror units in order to form a steerable beam. Software and hardware implementation
c. Study and simulation of optical configuration(s) for creating a system capable of short/long distance energy beaming. This includes the possibility of using multiple optical components and converting the solar light into laser light (solar pumped laser)
3. Conception, preparation and execution of one or more ground based experimental tests
4. Conception, preparation and execution of a preliminary space based experimental test
5. Conception, preparation and execution of an advanced mission, where a large sized distributed deflector will be deployed and tested in space. If the previous preliminary mission has been designed to be scalable, then the advanced mission can serve as a complement in order to expand the number of elements/units of the first mission.
Project success will be defined by milestones:
I. First important milestone is to produce a sound model of distributed light deflector.
II. Second milestone is to build and deploy a minimal version of such a model in space: a distributed deflector of about 5 meters diameter capable of directing and concentrating at least 10 kW of solar light power (at the distance of Earth from the Sun: about 1300 W/m2). A rough estimate of the deflection efficiency of a distributed mirror is about 45%. This considers a distance between the units equal to their extension (which means a total of 50% deflecting area) and a 90% mean light deflection efficiency of the single units.
III. Third milestone is to test the modularity and the scalability: build and deploy in space a 50 meters diameter distributed deflector capable of managing more than 1 MW. And so on.
IV. The final fantastic target is to reach the PW power levels needed for interstellar missions.
Note that the W/m2 solar radiation figure used above is referred to a mirror at the same approximate distance of the Earth from the Sun. For more ambitious missions (TW, PW power levels), it is preferred to set the deflector in the vicinity of the Sun, in order to reduce the overall dimensions.
[Preliminary animations of one possible embodiment of Project Solaris]
For more information: Distributed Solar Light Deflector Presentation
Would like to volunteer with Project Solaris? Drop an email at nbuldrini(at)icarusinterstellar.org!