The newly proposed propulsion system could theoretically ferry a heavy spacecraft out of the confines of our solar system in as little as 5 years — a feat that took the historic Voyager 1 probe 35 years to complete.
The concept, known as pellet beam propulsion, received an initial grant of $175,000 from NASA for further development earlier this year.
To be clear, the concept currently doesn’t exist beyond calculations on paper, so we can’t get too excited just yet.
However, it has garnered attention not only because of its ability to take us into interstellar space in a human lifetime — something conventional chemical-fueled rockets use. It can’t – but also because he claims to be able to do it with a much larger craft.
“This proposal examines a new propulsion architecture for the rapid transit of heavy payloads (1 ton and above) through the solar system into the interstellar medium,” explains the principal investigator behind the proposal, aeronautical engineer Artur Davuyan of the University of California, Los Angeles.
The concept of the pellet beam was inspired in part by the Revolutionary Star initiative which operates on the “light sail” propulsion system. With the help of millions of lasers, the tiny probe will theoretically be able to navigate to nearby Proxima Centauri in just 20 years.
The new proposal starts with a similar idea — dumping fuel on a rocket rather than detonating it — but looks at how to move larger objects. After all, a small probe isn’t necessarily what we need if we ever want to explore or colonize worlds outside our solar system ourselves.
To operate, the concept propulsion system requires two spacecraft – one that launches into interstellar space and one that orbits Earth.
The spacecraft orbiting the Earth will shoot a beam of tiny microparticles at the interstellar spacecraft.
These particles will be heated by the laser, causing some of them to fuse into the plasma causing the pellets to speed up, a process known as laser ablation.
These globules can reach 120 km/s (75 mi/s) and strike the interstellar spacecraft’s sail or repel a magnet inside, helping propel the spacecraft to huge speeds that allow it to exit the heliosphere – the bubble of solar wind around our solar system.
“Using the pellet beam, the outer planets can be reached in less than a year, 100 astronomical units [astronomical unit] in about 3 years and solar gravitational lensing at 500 AU in about 15 years,” Davoyan said.
For context, the AU, which stands for “astronomical unit,” is roughly the distance between Earth and the sun, or about 150 million kilometers (93 million miles).
It took 35 years of travel for the Voyager 1 probe to cross interstellar space in 2012, at a distance of about 122 astronomical units.
According to current projections, a 1-ton pellet-beam spacecraft could do the same thing in less than 5 years.
Davoyan explained to Matt Williams of Universe Today in February that his team took the pellet approach, rather than just using lasers like other sailing projects, because the pellets can be propelled by relatively low-energy lasers.
In their current projections, only a 10-mW laser beam can be used.
“Unlike a laser beam, the grains do not diverge as quickly, which allows us to accelerate heavier spacecraft,” Davoyan told Williams.
“The pellets are much heavier than photons, carry more momentum and can impart a higher force to a spacecraft.”
Of course, this is all just speculation for now. But the first phase of the NASA Innovative and Advanced Concepts (NIAC) grant would help.
The project was one of 14 funded at this early stage, and the next step will be to show proof of concept using experiments.
“In the Phase I effort, we will demonstrate the feasibility of the proposed propulsion concept by conducting detailed modeling of the various subsystems of the proposed propulsion architecture and conducting proof-of-concept pilot studies,” Davoyan said.
We will follow developments closely.