ESA Study Solar Sailing SPS reports and presentation on ResearchGate
k.a.c...@sympatico.ca
FYI:
Several of us in Toronto (myself, Steve Horvath, Henry Spencer) recently (in 2022/23) carried out a small study for ESA, on the topic of using solar radiation pressure to perform station-keeping of an SPS in GEO. This was done in response to an “ESA OSIP Campaign” on the topic of “Clean Energy - New Ideas for Solar Power from Space” from 2021:
The idea of using solar radiation pressure for this purpose is one that we’d seen suggested from time to time over the past few decades, by various SPS enthusiasts --- the idea being to reduce, or hopefully even eliminate, the on-going consumption of propellant for station-keeping, thus reducing the on-going ops costs for an SPS --- but as far as we knew nobody had actually done an analysis of this before. As we were all fairly knowledgeable about SPS and about solar sailing, and were somewhat interested in digging into this. Proposed this to ESA, and got a bit of funding as a result.
Net result: the concept can reduce the amount of SK propellant needed (at the cost of adding solar sailing equipment to the SPS, adding its own up-front cost, plus probably its own maintenance cost). But you can’t completely eliminate the need for SK propellant…*if* your goal is to control an SPS’s orbit in the same was as GEO commsat orbits are controlled (i.e., keeping them in a very narrow “longitude box”). This is because the unavoidable “leeward thrust” due to solar radiation pressure unavoidably causes some orbit ellipticity, and a solar sail can’t use SRP to get rid of this. You *can* use propellant to get rid of this, although it’s expensive. One of our main recommendations is to design your SPS constellation to just live with the resulting ellipticity --- in which case the solar sailing idea *can* pretty much eliminate the need for SK propellant consumption.
(Another concept is to not use GEO, but instead use a Laplace-plane orbit…that could result in the solar sail size maybe being much smaller.)
(It turns out that someone at Rockwell actually did look into this, in the 1970s, and published a very brief note on their study at one of the NAS/DOE SPS workshops. Maybe we dug into it a bit further than they did. In any case, their idea sank almost entirely without a trace since then, so at least we’re bringing it back to life…)
FYI, I have uploaded the Final Report and Executive Summary from last year, and the CASI Astro presentation from last week, to ResearchGate, here:
Final report:
Executive summary:
One of us (Steve) gave a presentation summarizing this at the CASI Astronautics conference in Toronto a few days ago, here are the slides for that:
- Kieran