NASA Take an In-Depth Look at Space Based Solar Power

NASA's Innovative Advanced Concepts (NIAC) program has started a Phase I effort to explore the overall viability and advance the Technology Readiness Level (TRL) for an orbital power station project called "SPS Alpha", or Solar Power Satellite - Alpha.

Last August, Artemis Innovation Management Solutions was selected for a NASA NIAC award to dive into the details of what Artemis leader John C. Mankins callls "the first practical solar-power satellite concept."  Mankins published his pdf report March 27th and we're now able to download the file. It runs 24 pages and is quite graphic rich.

SPS-Alpha Artists Rendition.

After the first few pages of what and who plus a couple historical views of graphics of old ideas Mankins gets to work on the state of the art as his firm sees it.

SPS-Alpha is a new idea inspired by biology similar to a hive of bees.  This idea brings together a large number of modules assembled to form an enormous satellite. The advantage is there is no single point of failure.  In orbit, at great cost and costly access, a near failsafe operation is key to the project being able to stand for financing.

Modular also offers individual elements, where no part is over 150kg in weight and manufacturability at scale and en mass.

Perhaps of even more import is SPS-Alpha uses a new optical configuration.  In the new iteration no large mirrors are needed, eliminating weight and points of failure.  Each element is intelligent, being its own local solar power generator using local power management and distribution, with a Wireless Power Transmission (WPT) system based on the 'retro-directive' phased array approach, local thermal management and built with a small 'flat' spacecraft bus formed in a hexagon to interconnect the modules.

The point of the Phase I study is to establish the technical and economic viability the SPS-Alpha idea to bring it up to a point where an analytical proof of concept can start to provide a framework for further study and develop technology.

Next common sense, in a bureaucratic sort of way, is applied.  Analyse the system end-to-end to see if it's feasible, identify and assess in more detail the key technology challenges needed with a measure of the critical technologies, get some selected technology into research and development, conduct a starting economic evaluation for viability and get a preliminary 'roadmap' for the research and development.

It seems NASA has thought this out.  The Phase I project has eleven steps and some have substeps.  Over three graphic representations, the report shows how over three stages the bureaucratic process can arrive and concluding analysis.

The report also looks at the main parts of the Solar Power Satellite including the hexagonal bus, a boom for the structure, the solar energy harvesting reflector, the interconnects, a power generation module, the WPT unit, plus a "PushMe-PullYou robot and ultimately the propulsion and attitude control system.

There's a lot to do.  NASA has already started assessing the risk.

So far NASA has held two workshops already this year with no 'Show-Stoppers" in evidence. The principle technologies issues centre on the wireless power transmission, end-to-end power, thermal, and system intelligence. It's now clear the hexagonal bus and the interconnects are the key systems.

The work is underway for mass estimates of refined systems and technologies and that has started the technology roadmap.

SPS-Alpha Operation Concept Graphic.

Early results show that a SPS-Alpha could be built using the modular design, a one thousand meter array would need 80,000 modules at a mass between 10 to 12,000 mt.

At this early date, the modelling shows that to size a system the time between refuelling platform propulsion and attitude control is a key parameter.

The new NASA study shows as have other private work that the technology risks are not significant and orbital stations are feasible.

The open questions remain, what does it cost and how much net power gets to the surface of the earth?  These are questions that are going to need demonstrations.  Those alone are very costly enterprises.  At the end what will ratepayers have to pay?

Orbital power is a fantastic idea and the new NASA report is as interesting as many already seen. Still that cost for power to consumers is an elusive number that has to come soon for credibility.

Have a look at the report.  Page 23 looks at some stunning cost to revenue numbers.

By. Brian Westenhaus

Source: NASA Starts to Get Serious On Space Based Solar Power