L.Garde has been involved in Solar Sail propulsion for many years. The inflatable structure technologies L.Garde has developed over the years have naturally led designers to a lightweight structure suitable for use in Solar Sail propulsion systems. Inflatable rigidizable technology combined with conical packing techniques allow for a highly scalable solar sail system design. L.Garde solar sails are a truly propellantless propulsion system for future missions.
The L.Garde 20m x 20m solar sail that successfully deployed inside NASA’s PlumBrook thermal-vacuum chamber in Sandusky, Ohio. One of the major challenges of ISPSS program was to develop super light adhesive system that could be applied in extremely thin layers (e.g. less than 0.1 Mils) to seams of 0.2-Micron thick sail membrane. We succeeded in doing so. The deployment was carried out using four independently-controlled Sub-Tg conically-deployed composite booms specifically formulated and designed for ISPSS Program. After qualification testing, including the thermal-vacuum test, the TRL level of the solar sail system was raised to between TRL 5 and 6. Both the bonding system and the sub Tg resin of the composite used to fabricate the booms for the ISPSS program was developed by Dr. Koorosh Guidanean, the proposed PI/PM for this proposal.
With this Solar Sail Technology Demonstration Mission (TDM), L.Garde will advance the state of the art of solar sailing. The end goal of this mission is the deployment, flight, and navigation of a mission capable solar sail to demonstrably prove the efficacy of solar sails. This proposed mission will definitively advance the technology of solar sailing for use by future mission planners. Solar sails offer many potential game-changing mission capabilities including the following:
- Debris collection and removal from orbit. Debris can be captured and removed from orbit over a period of years using the small solar-sail thrust.
- De-orbit of spent satellites. Solar sails can be integrated into satellite payloads so that the satellite can be de-orbited at the end of its mission.
- Creating pseudo-Lagrange points by cancelling some solar gravitational pull with the sails. As an example, the GeoStorm project considers locating solar storm warning satellites three times further from the Earth increasing warning time from 15 minutes to 45 minutes.
- Providing synchronous satellites at non-equatorial latitudes, such as the “pole-sitter” project. This allows the northern and southern latitudes to gain the advantages of synchronous satellites.
- Providing deep space propulsion. Payloads free of the Earth’s pull can be accelerated to the other planets, or out of the solar system, such as those proposed for Project Encounter.
However, without a definitive demonstration of a mission capable solar sail the technology is relegated to the realms of conceptual design. This TDM aims to boost the Technology Readiness Level (TRL) of the L.Garde solar sail from ~6 to ~9. The four main objectives of the mission are:
- Demonstrate segmented deployment of a solar sail with ~4X the area of that vacuum tested at Plum Brook, “cookie cut” from the center of a much larger sail.
- Demonstrate attitude control plus passive stability and trim using beam-tip vanes.
- Execute a navigation sequence with mission-capable accuracy.
- Fly to and Maintain Position at L1 and pole sitter positions
JPL funded this program to develop a 1.5m x 3.3m rigidizable structure triple-plane synthetic aperture radar. The as-built SAR had an areal density of 2 kg/m2 with a plane separation tolerance of better than 0.75 mm between layers with flatness of ±0.28 mm rms. The three panel membranes were tensioned with edge cords at the “catenary” edges resulting in an isotensoid stress state in the membrane. JPL provided the antenna RF design and the etched thin membranes. The SAR operated in the L-band.