The impossible task of traveling 25.6 trillion miles to Alpha Centauri, our closest star, is now possible. Using a Directed Energy System for Targeting of Asteroids and exploRation (DE-STAR), a versatile, scalable phased-array laser system, it can be reached in a short 16 years. Our project entails carrying out both computational and experimental studies of specific uses of DE-STAR to investigate photon recycling and spacecraft propulsion. Photon recycling is a unique term used to describe a form of energy conservation relative to this project. This effect will greatly improve the efficiency of spacecraft making interstellar flight more plausible. What lies beyond our solar system is one of the biggest mysteries of mankind and it finally has the potential to be solved.
The DESTAR interstellar laser propulsion system is modular, scalable and on a very rapid development path. It lends itself to a roadmap.
There has been a game change in directed energy technology whose consequences are profound for many applications including photon driven propulsion. This allows for a completely modular and scalable technology without "dead ends".
Laser efficiencies are near 50%. The rise in efficiency will not be one of the enabling elements along the road map but free space phase control over large distances during the acceleration phase will be. This will require understanding the optics, phase noise and systematic effects of our combined on-board metrology and off-board phase servo feedback.
Reflector stability during acceleration will also be on the critical path as will increasing the TRL of the amplifiers for space use. For convenience we break the roadmap into several steps. One of the critical development items for space deployment is greatly lowering the mass of the radiators. While this sounds like a decidedly low tech item to work on, it turns out to be one of the critical mass drivers for space deployment. Current radiators have a mass to radiated power of 25 kg/kw, for radiated temperatures near 300K. This is an area where some new ideas are needed. With our current Yb fiber baseline laser amplifier mass to power of 5kg/kw (with a likely 5 year roadmap to 1 kg/kw) and current space
photovoltaics of less than 7 kg/kw, the radiators are a serious issue for large scale space deployment.
The same basic system can be used for many purposes including both stand-on and stand-off planetary defense from virtually all threats with rapid response, orbital debris mitigation, orbital boosting from LEO to GEO for example, future ground to LEO laser assisted launchers, standoff composition analysis of distant object through molecular line absorption, active illumination of asteroids and other solar system bodies, beamed power to distant spacecraft among others. The same system can also be used for beaming power down to the Earth via micro or mm waves for selected applications. This technology will give us transformative options that are not possible now and allows us to go far beyond our existing chemical propulsion systems.
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Consider a 1 gram payload attached to a 0.7 meter diameter sail. Image Adrian Mann
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Fiber solid state lasers (SSLs) are widely used in industry—tens of thousands are used by auto and truck manufacturing firms for cutting and welding metal. They are considered to be a very robust technology. One fiber SSL prototype demonstrator developed by the Navy, called the Laser Weapon System(LaWS), had a beam power of 33 kW.
Operational Maturation and Steps:
Step 1 - Ground based - Small phased array, beam targeting and stability tests - 10 kw
Step II – Ground based - Target levitation and lab scale beam line acceleration tests - 10 kw
Step III – Ground based - Beam formation at large array spacing –
Step IV – Ground based - Scale to 100 kW with arrays sizes in the 1-3 m size –
Step V – Ground based - Scale to 1 MW with 10 m optics –
Step VI – Orbital testing with small 1-3 class arrays and 10-100kw power – ISS possibility
Step VII – Orbital array assembly tests in 10 m class array
Step VIII – Orbital assembly with sparse array at 100 m level –
Step IX – Orbital filled 100 m array
Step X – Orbital sparse 1km array
Step XI – Orbital filled 1 km array
Step XII – Orbital sparse 10 km array
Step XIII – Orbital filled 10 km array
The more modest size systems can be completely tested on the ground as well as sub-orbital flight tested on balloons or possibly sounding rocket. While the largest sized systems (km scale) are required for interstellar missions, small systems have immediate use for roadmap development and applications such as sending small probes into the solar system and then working our way outward as larger laser arrays are built. The laser array is modular, leading to mass production, so that a larger array can be built by adding elements to a smaller array. Array testing and propulsion tests are feasible at all levels allowing for roadmap development rather than "all or nothing". Small array can also be used for orbital debris removal, ISS defense from space debris as well as stand-on systems for planetary defense so again there is a use at practically every level and funding is well amortized over multiple uses. This allows practical justification for construction. In addition there is an enormous leveraging of DoD and DARPA funds for Directed Energy systems that dramatically lowers the NASA costs.
Phase lockable lasers and current PV performance - New fiber-fed lasers at 1 μm have efficiencies near 40% (DARPA Excalibur program currently at 5 kg/kW with near term goal of 1 kg/kW). They assume incremental efficiency increases to 70% though current efficiencies are already good enough to start the program. It is conceivable that power density could increase to 10 kW/kg in 10-20 years given the current pace. Current space multi-junction PV has an efficiency of nearing 40% with deployable mass per power of less than 7 kg/kW (ATK Megaflex as baselined for DE-STARLITE). Multi junction devices with efficiency in excess of 50% are on the horizon with current laboratory work exploring PV at efficiencies up to 70% over the next decade. We anticipate over a 20 year period PV efficiency will rise significantly, though it is NOT necessary for the roadmap to proceed. The roadmap is relatively "fault tolerant" in technology develop. Array level metrology as a part of the multi level servo feedback system is a critical element and one where recent advances in low cost nanometer level metrology for space applications is another key technology. One surprising area that needs significant work is the simple radiators that radiate excess heat. Currently this is the largest mass sub system at 25 kg/kw (radiated). The increase in laser efficiency reduces the radiator mass as does the possibility to run the lasers well above 300K. Radiation hardening/ resistance and the TRL levels needed for orbital use are another area they are currently exploring.
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The DESTAR interstellar laser propulsion system is modular, scalable and on a very rapid development path. It lends itself to a roadmap.
There has been a game change in directed energy technology whose consequences are profound for many applications including photon driven propulsion. This allows for a completely modular and scalable technology without "dead ends".
Laser efficiencies are near 50%. The rise in efficiency will not be one of the enabling elements along the road map but free space phase control over large distances during the acceleration phase will be. This will require understanding the optics, phase noise and systematic effects of our combined on-board metrology and off-board phase servo feedback.
Reflector stability during acceleration will also be on the critical path as will increasing the TRL of the amplifiers for space use. For convenience we break the roadmap into several steps. One of the critical development items for space deployment is greatly lowering the mass of the radiators. While this sounds like a decidedly low tech item to work on, it turns out to be one of the critical mass drivers for space deployment. Current radiators have a mass to radiated power of 25 kg/kw, for radiated temperatures near 300K. This is an area where some new ideas are needed. With our current Yb fiber baseline laser amplifier mass to power of 5kg/kw (with a likely 5 year roadmap to 1 kg/kw) and current space
photovoltaics of less than 7 kg/kw, the radiators are a serious issue for large scale space deployment.
The same basic system can be used for many purposes including both stand-on and stand-off planetary defense from virtually all threats with rapid response, orbital debris mitigation, orbital boosting from LEO to GEO for example, future ground to LEO laser assisted launchers, standoff composition analysis of distant object through molecular line absorption, active illumination of asteroids and other solar system bodies, beamed power to distant spacecraft among others. The same system can also be used for beaming power down to the Earth via micro or mm waves for selected applications. This technology will give us transformative options that are not possible now and allows us to go far beyond our existing chemical propulsion systems.
Fiber solid state lasers (SSLs) are widely used in industry—tens of thousands are used by auto and truck manufacturing firms for cutting and welding metal. They are considered to be a very robust technology. One fiber SSL prototype demonstrator developed by the Navy, called the Laser Weapon System(LaWS), had a beam power of 33 kW.
Operational Maturation and Steps:
Step 1 - Ground based - Small phased array, beam targeting and stability tests - 10 kw
Step II – Ground based - Target levitation and lab scale beam line acceleration tests - 10 kw
Step III – Ground based - Beam formation at large array spacing –
Step IV – Ground based - Scale to 100 kW with arrays sizes in the 1-3 m size –
Step V – Ground based - Scale to 1 MW with 10 m optics –
Step VI – Orbital testing with small 1-3 class arrays and 10-100kw power – ISS possibility
Step VII – Orbital array assembly tests in 10 m class array
Step VIII – Orbital assembly with sparse array at 100 m level –
Step IX – Orbital filled 100 m array
Step X – Orbital sparse 1km array
Step XI – Orbital filled 1 km array
Step XII – Orbital sparse 10 km array
Step XIII – Orbital filled 10 km array
The more modest size systems can be completely tested on the ground as well as sub-orbital flight tested on balloons or possibly sounding rocket. While the largest sized systems (km scale) are required for interstellar missions, small systems have immediate use for roadmap development and applications such as sending small probes into the solar system and then working our way outward as larger laser arrays are built. The laser array is modular, leading to mass production, so that a larger array can be built by adding elements to a smaller array. Array testing and propulsion tests are feasible at all levels allowing for roadmap development rather than "all or nothing". Small array can also be used for orbital debris removal, ISS defense from space debris as well as stand-on systems for planetary defense so again there is a use at practically every level and funding is well amortized over multiple uses. This allows practical justification for construction. In addition there is an enormous leveraging of DoD and DARPA funds for Directed Energy systems that dramatically lowers the NASA costs.
Phase lockable lasers and current PV performance - New fiber-fed lasers at 1 μm have efficiencies near 40% (DARPA Excalibur program currently at 5 kg/kW with near term goal of 1 kg/kW). They assume incremental efficiency increases to 70% though current efficiencies are already good enough to start the program. It is conceivable that power density could increase to 10 kW/kg in 10-20 years given the current pace. Current space multi-junction PV has an efficiency of nearing 40% with deployable mass per power of less than 7 kg/kW (ATK Megaflex as baselined for DE-STARLITE). Multi junction devices with efficiency in excess of 50% are on the horizon with current laboratory work exploring PV at efficiencies up to 70% over the next decade. We anticipate over a 20 year period PV efficiency will rise significantly, though it is NOT necessary for the roadmap to proceed. The roadmap is relatively "fault tolerant" in technology develop. Array level metrology as a part of the multi level servo feedback system is a critical element and one where recent advances in low cost nanometer level metrology for space applications is another key technology. One surprising area that needs significant work is the simple radiators that radiate excess heat. Currently this is the largest mass sub system at 25 kg/kw (radiated). The increase in laser efficiency reduces the radiator mass as does the possibility to run the lasers well above 300K. Radiation hardening/ resistance and the TRL levels needed for orbital use are another area they are currently exploring.
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