With its positive charge, each tether acts like a huge barrier to the solar wind, giving the spacecraft an effective surface area of 600 square kilometers once it launches from the Earth. By slowly rotating the spacecraft, the centrifugal forces will stretch the tethers out into this circular shape. The Heliopause Electrostatic Rapid Transit System, or HERTS spacecraft would extend 20 of these electric tethers outward from the center, forming a huge circular electric sail to catch the solar wind. Pekka Janhunen and his team to explore how this technology could be used to reach the outer solar system in less time than other methods. In 2015, NASA announced that they had awarded a Phase II Innovative Advanced Concepts grant to Dr. It's not just the Finns who are considering this propulsion system. We should find out if the technique is viable later this year. The Finnish Aalto-1 satellite was launched in June 2017, and one of its experiments is to test out an electric sail. An Estonian prototype satellite was launched back in 2013, but its motor failed to reel out the tether. It's an incredibly versatile propulsion system, and the sun does all the work.Īlthough this sounds like science fiction, there are actually some tests in the works. ![]() But you could also strike the other side and lower its orbit, allowing it to journey down into the inner solar system. Strike the sail on one side and you raise its orbit to travel to the outer solar system. Interstellar space is dominated by plasma, ionized gas (illustrated here as brownish haze), that was thrown off by giant stars millions of years ago. This artist’s concept shows the Voyager 1 spacecraft entering the space between stars. Depending on which side of the sail the solar wind hits, it either raises or lowers the spacecraft's orbit from the sun. Just like with solar sails, a electric sail can be pivoted. I'm sure you're wondering if this is a one-way trip to get away from the sun, but it's actually not. So an electric sail-powered spacecraft would need to be carried by a traditional rocket away from the Earth before it could unfurl its sail and head out into deep space. One of the downsides of the method, actually, is that it won't work within the Earth's magnetosphere. So, much faster, definitely on an escape velocity from the solar system. Just for comparison, the fastest spacecraft out there, NASA's Voyager 1, is merely going about 17 km/s. Over the course of a year, this spacecraft could be going 30 km/s. In the first second it travels 1 mm, and then 2 mm in the next second, etc. For example, if a 1000 kg spacecraft had 100 of these wires extending out in all directions, it could receive an acceleration of 1 mm per second per second. The amount of acceleration is very weak, but it's constant pressure from the sun and can add up over a long period of time. As the negatively charged particles from the sun encounter the positively charged tether, they "see" it a huge obstacle 100 meters across, and crash into it.īy imparting their momentum into the tether and spacecraft, the ions accelerate it away from the sun. ![]() Credit: JPLīy shooting electrons off into space, the spacecraft maintains a highly positive charged state. The layers can be squeezed tightly enough to reconnect and deliver solar electrons (yellow sparkles) directly into the upper atmosphere to create the aurora. Clouds of southward-pointing plasma are able to peel back layers of the Sun-facing bubble and stack them into layers on the planet’s nightside (center, right). ![]() Visualization of the solar wind encountering Earth’s magnetic “defenses” known as the magnetosphere. As you probably know, there's a steady stream of charged particles, mainly electrons and protons, zipping away from the sun in all directions. That deadly ball of radiation in the sky. To understand how this works, I'll need to jam a few concepts into your brain.įirst, the sun. Pekka Janhunen, has proposed building an electric sail that will use these particles to carry spacecraft out into the solar system. A team of engineers from Finland, led by Dr. In addition to light, the sun is also blowing off a steady stream of charged particles – the solar wind. Although photons are massless, they do have momentum, and can transfer it when they bounce off a reflective surface. But there's another propulsion system that keeps coming up, and I totally forgot to mention, but it's one of the best ideas I've heard in awhile: electric sails.Īs you probably know, a solar sail works by harnessing the photons of light streaming from the sun. A few weeks ago, I tackled a question someone had about my favorite exotic propulsion systems, and I rattled off a few ideas that I find exciting: solar sails, nuclear rockets, ion engines, etc.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |