Space-based Solar Power

Space-based solar power (SBSP) (or historically space solar power (SSP)) is a system for the collection of solar power in space, for use on Earth. SBSP differs from the usual method of solar power collection in that the solar panels used to collect the energy would reside on a satellite in orbit, often referred to as a solar power satellite (SPS), rather than on Earth's surface. In space, collection of the Sun's energy is unaffected by the day/night cycle, weather, seasons, or the filtering effect of Earth's atmospheric gases.

Average solar power per unit area outside Earth's atmosphere during any given time period is about 136%[citation needed] that available on Earth's surface during direct sunlight (1336 W/m2). A major interest in SBSP stems from the length of time the solar collection panels can be exposed to a consistently high amount of solar radiation. For most of the year, a satellite-based solar panel can collect power 24 hours per day, whereas a land-based station can collect for only 12 hours per day, yielding lower power collection rates around the sunrise and sunset hours.

The collection of solar energy in space for use on Earth introduces the new problem of transmitting energy from the collection point, in space, to the place where the energy would be used, on Earth's surface. Since wires extending from Earth's surface to an orbiting satellite would be impractical, many SBSP designs have proposed the use of microwave beams for wireless power transmission. The collecting satellite would convert solar energy into electrical energy, which would then be used to power a microwave emitter directed at a collector on the Earth's surface. Dynamic solar thermal power systems are also being investigated.

JUPITER'S TEMPORARY MOON

 Jupiter's Temporary Moon For 12 Years:


Jupiter snared a passing comet in the middle of the last century, eventually releasing it 12 years later, astronomers reported on Monday.


Data presented at the European Planetary Science Congress in Potsdam, near Berlin, showed that the biggest planet of the Solar System gained a temporary satellite, a comet called 147P/Kushida-Muramatsu, between 1949 and 1961.

It is only the fifth captured comet to be identified, a press release said.

Comets are lonely wanderers of the Solar System, sometimes taking decades or even centuries to complete a long orbit around the Sun.

On rare occasions, though, these enigmatic bodies of ice and dust can wander into the vicinity of a planet, where they are netted by its gravitational pull.

Sometimes, the comet breaks up and smashes into the planet, as was famously the case with Comet Shoemaker-Levy 9, whose fragments smashed into Jupiter in 1994.

Most of the observed temporary captures have been flybys, in which a comet does not complete a full orbit before wresting itself free.

Kushida-Muramatsu, though, completed two full revolutions of Jupiter, following an irregular orbit, before it gained its freedom, according to calculations led Katsuhito Ohtsuka of the Tokyo Meteor Network.

"The results of our study suggests that impacts on Jupiter and temporary satellite capture events may happen more frequently than we previously expected," said David Asher of Northern Ireland's Armagh Observatory, who presented the data in Potsdam.

The study has a bearing for understanding the risk of a cometary impact on Earth, an event that would wreak catastrophic damage. A colliding asteroid or comet is believed to have ended the long reign of the dinosaurs some 65 million years ago.

Jupiter is often seen as a "goalkeeper" that takes hits from comets that could possibly endanger Earth.
But it can deflect passing comets, too, altering their track around the Sun.

Thus understanding how this process works will help astronomers trying to evaluate the risk to Earth from rogue rocks.
Comet Kushida-Muramatsu appears to have avoided the fate of Shoemaker-Levy 9 "for the foreseeable future," said Levy.