NASA has developed an innovative new solar technology that can accelerate to speeds of up to three times that of the famed Voyager simply by harnessing the electrical power of the Sun.
NASA believes that it’s new E-Sail technology will allow us to reach the edge of our solar system in just 10 years. In comparison, the Voyager, the famed space probe that has just reached interstellar space, took 35 years to leave the cosmic neighbourhood. What is most interesting, is that the E-Sail won’t be making use of jet propulsion, but a newly developed technology that rides the waves of our Sun’s Solar wind. It seems ironic that sailing through space, rather then jetting our way around as we currently do, turns out to be a much more efficient, and powerful mode of transportation.
The E-Sail is a curious creature. To be able to capture as much of the Sun’s energy, the small space probe will spider and expand out to be 40km. Once in space the E-Sail or the HERTS (Heliopause Electrostatic Rapid Transit System) will begin unveiling long, positively charged aluminium wires designed to harness the free flying electrons and protons that emanate from the Sun’s volatile surface. To go into more detail, the wires are positively charged so as to repel any protons that might come into contact with it, while capturing electrons, only to fire them from the vessels ‘electron gun’.
Touching on the ever-reliable Laws of Motion, the momentum within a closed system must at all times be conserved. So, when energised protons bounce off the E-Sail and lose some of their ‘kinetic energy’ it is transferred to the space probe. Electrons on the other hand are collected before being fired in the opposite direction to that which the ship wishes to travel, however due to the relativity miniscule weight they will not contribute greatly to the momentum of the craft. The same way a jet engine is provided with thrust by firing burning gas in the opposing direction of intended travel, the E-Sail fires and reflects electrically charged particles to gain additional momentum. Due to their being no friction in space, applying Newton's law again, once in motion the vessel tends stay in motion.
However, due to the sails being constantly bombarded with the continuous stream of protons and electrons, the vessels momentum begins to slowly accumulate and increase, without any resistance to slow it down. After about three years the humble E-Sail will have accumulated enough kinetic energy to reach speeds of 100-150/sec.
NASA is currently testing the technology using a High Intensity Solar Environment Test system, in an attempt to analyse the actual rate in which protons and electrons will come into contact with the aluminum wires, essentially determining the efficiency of the technology. NASA is also testing how effective the electron gun is when ejecting negative charge. This is important because the wires needs to remain positively charged at all times to be effective. Surprisingly the wires will only be around a millimeter thick. The vessel will rotate at on revolution an hour to create centripetal force, similar to the ship from Interstellar. This will mean that the wires, despite their flexibility, will remain in position, and due to the slow rate of acceleration, each wire should maintain its position.
The original sail like technology was devised by Dr. Pekka Janhunen from the Finnish Meteorological Institute and received the quality innovation award for 2010. Five years later and the potential for this unique spacecraft is being taken seriously, but it may be a while before we see a HERTS vessel traversing the galaxy. Right now, the technology is predicted to be available by 2025, and that's only if the tests being conducted now show potential for its use.
A quick comparison against other space tech however, shows that the HERTS spacecraft shows the greatest potential. For example, previous solar sails that rely on photons instead, which happen to look more closely related to their ocean bound cousins, only cover an area of 200m by 200m. Whereas Ion propulsion systems are only able to accelerate up until the thrusters give out. The newly hypothesised E-Sail however can expand to an effective area of 600-1200 sq km. The ship will also be powered by traditional solar panels, which will aid in generating the required electricity for the ship.
The greater diameter allows the probe to accelerate for distances far beyond that of any other propulsion systems. The Solar Sail technology for example stops accelerating just beyond Mars as the density of photons begins to decrease. Bruce Wiegmann, and engineer for the Advanced Space Concepts division of NASA and the head investigator of the E-Sail technology said:
“The same concerns don’t apply to the protons in the solar wind,” he said. “With the continuous flow of protons, and the increased area, the E-Sail will continue to accelerate to 16-20 AU -- at least three times farther than the solar sail. This will create much higher speeds.”
Essentially to objective of the HERTS vessel is to get us into deep space quickly, and more efficiently. While we might not be entering hyperspace and travelling at light speed just yet, using advanced solar technology we might be able to reduce the waiting time of space travel significantly. It seems even in space, harnessing the energy from the sun is a more efficient and practical way to power transportation, instead of relying on finite fuels. Forget about electric cars, solar energy is powering space travel too.