Maneuvering with PLT In addition to propellant-free thrusting capability, PLT can provide “out-of-plane” maneuvering capability that enables unprecedented persistent formation flying that is needed for nextgeneration space endeavors. An example of such unprecedented formation flying configurations is shown in Figure 2. In this structure, pushing-out photon thrust is counter balanced by gravity gradient. In addition, PLT can enable propellantless “perpetual” station-keeping by beaming thrust from a resource vehicle to a mission vehicle.
Figure 3 illustrates two examples of the “perpetual” station-keeping. In the first example, north-south station-keeping of a resource vehicle in GEO is performed by beaming thrust from a resource vehicle in GTO, which is much less costly than GEO to reach. In the second example, a resource satellite orbiting in LEO beams thrust to multiple mission satellites in LEO for orbit drag compensation for station-keeping. Such PLT station-keeping emulates aerial fueling between a jetfighter and a fuel tanker and drastically reduces the amount of onboard fuel needed for mission vehicles.
Currently, we are developing a mNclass PLT capable of delivering photon thrust up to 5 mN by adapting an off-theshelf 1 kW class Thin Disk Laser. We are also developing space-qualified PLTs for a flight demonstration that will involve a small satellite and a CubeSat under the auspices of NIAC. In this scenario, the small satellite will be a resource vehicle that carries a PLT engine and a power source and the CubeSat will be a mission vehicle that carries with it an HR mirror with diagnostic and attitude control hardware. Such flight demonstration is predicted to be achievable in 3 – 5 years after completion of the present NIAC Phase II program.
If successfully implemented, PLT can Enable virtually unlimited mission lifetimes and expand operational capabilities, since advanced spacecraft maneuverings are no longer limited by onboard fuel;
• Enable unprecedented “out-of-plane” maneuvers that include persistent precision formation flying;
• Lower construction/operation costs by reducing the hardware required for higher orbit applications;
• Eliminate environmental contamination or damage to mission crucial elements during proximate operations from cross firing of traditional thrusters;
• End risks to personnel health, safety and environmental impact compared to current toxic propellants.
PLT, therefore, promises to enable innovative CONOPS to change how some current spacecraft endeavors are conceived, making the PLT spacecraft system a revolutionary departure from the “all-in-one” single-spacecraft app - roach, where a primary factor that dominates spacecraft design is a heavy and risk-intolerant science payload. Instead, PLT spacecraft maneuvering has evolved from a different path based on inter-body dynamics via thrust exchange. PLT spacecraft maneuvering really represents a technology push rather than a mission pull, and will enable an entirely new generation of planetary, heliospheric, and Earth-centric space endeavors.