Space Solar Power Demonstrator (SSPD) launched on January 3rd may be a breakthrough for harvesting solar energy from space.

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A Caltech-designed prototype satellite containing an experiment, the Space Solar Power Demonstrator (SSPD), was launched on January 3rd of this year in what could prove to be a breakthrough for harvesting the energy of the Sun from space. The satellite goes by the name Momentus Vigoride and hitched its ride into space on a SpaceX Falcon 9 rocket.

Solar energy from space has been the dream of science fiction writers beginning with Isaac Asimov back in 1941 in a short story called Reason which later was included in a collection that Asimov published in 1950 entitled I, Robot. In the story, Asimov described a space station that collected energy from the Sun and transmitted it by microwave beam to various locations. Asimov recognized the distinct advantage of building solar power generating stations in space out of the Earth’s shadow and therefore continuously being able to harvest the energy of the Sun.

When the first telecommunication satellites were launched into geosynchronous orbits around Earth, it became obvious that not just communications could be offered in a continuous stream using satellite technology. A photovoltaic array parked in a similar orbit would stream electrical energy to Earth ground receivers. And depending on the size of an array deployed at that altitude, a satellite or a few of them to ensure no single failure, could become an endless supplier of all the energy the planet would need. There were technical problems still to work out.

This month, NASA launched a new Earth-monitoring satellite that will observe fresh water systems across the planet. Now, the satellite has unfurled in space ready to begin science operations, and NASA has shared a video showing the unfolding process.

Named the Surface Water and Ocean Topography (SWOT) satellite, it had been folded up to fit inside the SpaceX Falcon 9 rocket which launched it from Vandenberg Space Force Base in California on December 16. Once the satellite reached space, it had to deploy its solar panel arrays, then unfold its mast and antenna panels. While deploying the solar panel arrays was a quick process, taking place shortly after launch, the unfolding of the antennae was much more involved and took four days.

As the SWOT satellite has a camera at the end of its long master, used for its Ka-band Radar Interferometer (KaRIn) instrument, these cameras were able to capture the unfolding process on video. This instrument is a new type of interferometer that will be able to see the depth of fresh water bodies such as lakes and rivers by using radar pulses. It sends two radar pulses down to the surface with a slight offset, allowing researchers to see the depth of these features. This is possible because of the wide spread of its two antennae, spaced 10 meters apart.

The Surface Water and Ocean Topography (SWOT) satellite launched into Earth orbit on Friday, Dec. 16, from Vandenberg Space Force Base in central California, and engineers are working to prepare the mission to begin measuring the height of water on over 90% of Earth’s surface, providing a high-definition survey of our planet’s water for the first time.

But before it can do that, the satellite would need to unfold its large mast and antenna panels (see above) after successfully deploying the solar panel arrays that power the spacecraft. The mission monitors and controls the satellite using telemetry data, but it also equipped spacecraft with four customized commercial cameras to record the action.

The solar arrays fully deployed shortly after launch, taking about 10 minutes.