In order to reach the outer edges of our solar system as fast as possible, NASA's Marshall Space Flight Center is in the process of developing a plan for massive solar sails that will allow humans to reach the heliopause - the edge of our solar system - in about 10 years.
Current propulsion technologies are neither fast nor efficient enough to reach the heliopause in this time frame due to the limitations of chemical fueled rockets and ion engines. Solar sails are an ideal alternative due to the minimal fuel requirements and their ability to continuously accelerate.
"Our investigation has shown that an interstellar probe mission propelled by an E-Sail could travel to the heliopause in just under 10 years," said Bruce Wiegmann, engineer and principal investigator for the project. "This could revolutionize the scientific returns of these types of missions."
The project is called the Heliopause Electrostatic Rapid Transit System (HERTS) E-Sail and the main drive is planned to have 10 to 20 electrically charged aluminum wires extending from its central hub. These wires will measure up to 20 millimeters in length and one millimeter across, giving the drive a surface area of 600 square kilometers when close to the Earth and as much as 1200 square kilometers when fully deployed due to centrifugal force.
The HERTS system will take advantage of solar wind just like all other solar sails. It will utilize the constant stream of photons and electrons released into the solar system by the sun, allowing it to ride them with the sail.
"The sun releases protons and electrons into the solar wind at very high speeds - 400 to 750 kilometers per second," said Wiegmann. "The E-Sail would use these protons to propel the spacecraft."
The positive electrical charge of the aluminum wires will create a repulsion force when the electrons in the solar wind strike the sail, creating acceleration strong enough to bring the spacecraft to the edge of the solar system.
The only downside to NASA's ambitious model is that it will not have the ability to turn around, meaning any trips to the heliopause would be one-way. Furthermore, engineers are still trying to figure out how to control potential interference from the electrons that drive the propulsion in order to prevent the sail from losing the proper charge.
