Concept of NASA’s diffractive solar sail project. NASA: “When the sun sneezes, the Earth catches a cold.”
This is how scientists commonly describe the solar wind. This means that the negative impact on the Earth is that great. Scientists are seeking ways to overcome this negative impact and utilize solar wind positively.
According to the science and technology community on the 18th, the National Aeronautics and Space Administration (NASA) is carrying out the ‘Diffractive Solar Sailing Project’. The goal is to develop technology that uses the solar wind, which spreads from the sun throughout space, as power for spacecraft. Just like a sailing ship that uses the wind to cross the ocean, a spacecraft will use the solar wind to travel through space.
To achieve this, a solar sail to utilize the solar wind is needed. Existing sails that use solar wind are very large and are not suitable for spacecraft. There is also a limitation in that power is limited depending on the direction of sunlight. The NASA research team develops a sail that uses the ‘diffraction’ phenomenon. Diffraction is a phenomenon in which waves bend at the edges of a boundary. When a wave passes through a very small gap, it spreads around. It does not exist only on a path that passes through the gap in a straight line, but spreads.
Diffraction sails use tiny gratings embedded in thin films to create a diffraction effect. This will allow the spacecraft to use solar wind as power more efficiently. NASA’s analysis is that unlimited fuel can be supplied.
NASA had already launched a small test satellite powered by solar wind using a diffraction sail in 2011. By placing it in Earth’s orbit, it proved the possibility of using solar wind as spacecraft power.
Afterwards, after going through a technology development process, solar sails were applied to the mission for the first time in November last year. The ‘Near-Earth Asteroid Scout (NEA Scout)’ equipped with a solar sail was launched. NEA Scout is approaching the asteroid ‘GE 2020’ using solar wind as power. GE 2020, which orbits the sun, will be closer to the Earth at a distance of 659,949 km in September next year. NEA Scout heads to the sun after exploring GE 2020. The plan is to fly close to the sun and carry out a mission to monitor space weather.
Solar winds also bring unintended positive effects. It is to dispose of space debris, which has recently emerged as a nuisance to humanity.
Space junk is trash floating around in outer space. Since humanity launched its first satellite in 1957, more than 10,000 satellites have been launched into space. Among these, there are about 6,700 satellites currently in operation. This means that all remaining satellites that have reached the end of their lifespan have become space debris. As satellite launches become more frequent, space debris is increasing. Garbage is interfering with the launch of new satellites and astronomical research. Sometimes they fall to Earth and cause direct harm to humanity.
Scientists analyze that space debris is removed from orbit when strong solar winds occur. The solar wind expands the atmosphere, creating more friction on pieces of space debris in orbit, and eventually the space debris enters the Earth’s atmosphere and burns up. NASA explained, “We are tracking more than 22,000 pieces of space debris,” and “the solar wind is one of the big factors affecting the location of space debris.”
[고재원 기자]
