The vehicles that will take astronauts into space in the next century are an oft-discussed subject, with various companies comprising presenting an array of designs.
But what about how the spacecraft will transport its passengers? The answer could be…electrifying.
Florida Tech astrobiology assistant professor Manasvi Lingam, alongside Harvard University science professor Abraham Loeb, recently published a paper in the journal Acta Astronautica that compared the effectiveness of electric sails to light sails.
Electric sails are a propulsion system that generate momentum via the deflection of stellar wind particles through electric forces, while light sails use radiation pressure exerted by sunlight to accelerate over time.
Using a multitude of formulas and examining factors such as deceleration caused by traveling between stars (and thus not receiving propulsion), Lingam and Loeb analyzed the properties of electric sails for different stellar systems. Electric sails were compared with light sails powered by stellar radiation, with the research finding electric sails outperformed light sails for most stellar systems.
For example, electric sails were capable of achieving terminal speeds of 0-500 km/s (1,118,468 mph) over a year for M-dwarfs, which are common stars comprising approximately 70 percent of all the stars in the galaxy. The sails’ speed also would be 20 to 50 times faster than current rockets, which travel at 10-20 km/s (22,369-72,000 mph).
Lingam noted under optimal conditions, with Earth and Mars at the shortest distance from one another, one could get to the red planet “in a few months” with an electric sail-equipped spacecraft. Unmanned spacecraft have taken up to 10 months to reach Mars previously.
The lighter design of the electric sail spacecraft also allows for faster travel than a shuttle or rocket.
“The bulk of the rocket’s mass is actually made of liquid fuel, whereas the electric sail gets its fuel for free, in a sense,” Lingam said. “It’s basically using all of the wind energy of the sun. It doesn’t have to carry the fuel on board because it uses the sun and can reach higher speeds without expending as much energy as a heavier object would.”
While the benefits of electric sails may have some seeking to use them soon, Lingam noted that sails have only been discussed for the last 13 years, compared to the over 60-year history of the modern rocket. However, a push to design sails is underway, with some analysts estimating spacecraft equipped with them within the next five to 10 years.
As the rocket made it possible for humans to explore the starts, electric sails may be the next breakthrough in space transportation. The opportunity to be part of spacecraft designs’ evolution is one that resonates with Lingam.
“The future for alternative propulsion technologies such as electric sails that do not require onboard fuel is decidedly promising and may become practical in the near-future,” Lingam said. “It is exciting to live in an era where humanity is taking its first serious steps toward becoming an interstellar species, and I consider myself very lucky to be contributing to such an endeavor.”