by This week’s announcement of fusion ignition is a major scientific breakthrough, one that has been in the works for decades. More energy was produced than the laser energy used to trigger the first triumph of controlled fusion.
The result: reproduce the fusion that powers the sun.
On December 5, a team from the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory passed the milestone. As noted by Kim Budil, director of the lab: “Crossing this threshold is the vision that has driven 60 years of dedicated pursuit – a continuous process of learning, building, expanding knowledge and capability, and then finding ways to overcome the new challenges that have emerged,” said Budil.
The feat of nuclear fusion has wide-ranging implications, fueling hopes for unlimited clean energy. As far as space exploration is concerned, one of the results of this historic research is the realization of the long-held dream of future rockets powered by fusion propulsion.
But is this perspective still a chimera or is it now considered accessible? If so, what future do we envision?
Related: Major breakthrough in pursuit of nuclear fusion unveiled by US scientists
Data points
This fusion breakthrough is good news for physicist Fatima Ebrahimi of the US Department of Energy’s (DOE) Princeton Plasma Physics Laboratory in New Jersey.
Ebrahimi said the success of the NIF is extraordinary.
“All of the data points obtained showing the achievements of fusion energy science are fantastic! A fusion energy gain greater than one is quite an achievement,” Ebrahimi said. However, technical innovations are still needed for the NIF to be commercially viable as a fusion reactor, she added.
Ebrahimi is investigating the best way to propel humans to higher speeds to Mars and beyond. The work involves a new concept rocket booster, which harnesses the mechanism behind solar flares.
The idea is to accelerate particles using “magnetic reconnection”, a process found throughout the universe, including the surface of the sun. This is when magnetic field lines converge, suddenly separate, then rejoin, producing charges of energy. By using more electromagnets and more magnetic fields, Ebrahimi envisions the possibility of creating, in effect, a way to turn the knob to fine-tune the speed.
As for the NIF victory impacting space exploration, Ebrahimi said that for space applications, compact fusion concepts are still needed. “Heavy components for space applications are not favorable,” she said.
Necessary precursor
Paul Gilster, writer/editor of the informative Centauri Dreams website, is similar in thought.
“Naturally, I celebrate the NIF’s accomplishment of producing more energy than was originally put into the fusion experiment. It’s a necessary precursor to integrating fusion into the game as an energy source. “, Gilster told Space.com. Building on the notable breakthrough is going to take time, he said.
“Where we’re going as this evolves, and it looks like it’s several decades away, is towards actual fusion power plants here on Earth. and the weight constraints of a spacecraft,” Gilster said.
There’s no doubt in Gilster’s mind that fusion can be handled for space exploration purposes, but he suspects it’s still more than a few decades in the future.
“So this work is encouraging, but it shouldn’t diminish our research into alternatives such as radiant energy as we consider missions beyond the solar system,” Gilster said.
Escape Velocities
Richard Dinan is the founder of Pulsar Fusion in the UK. He is also the author of the book “The Fusion Age: Modern Nuclear Fusion Reactors”.
“Fusion propulsion is a much simpler technology to apply than fusion for energy. If fusion is feasible, which people are finally starting to see, then fusion energy and propulsion are inevitable,” said said Dinan. “One gives us the ability to power our planet indefinitely, the other the ability to leave our solar system. That’s a really big deal.”
The escape velocities generated from a fusion plasma, Dinan said, are calculated to be about a thousand times greater than those from a Hall-effect thruster, an electric propulsion device that uses electric and magnetic fields to create and eject a plasma.
“The financial implications that come with it make fusion propulsion, in our view, the most important emerging technology in the space economy,” Dinan said.
Pulsar Fusion has been busy working on a direct fusion drive initiative, a steady-state fusion propulsion concept based on a compact fusion reactor.
According to the group’s website, Pulsar Fusion has completed a phase 3 task, manufacturing an initial test unit. Static tests are expected to take place next year, followed by an in-orbit demonstration of the technology in 2027.
Aspirational glow
“The net energy gain reported in the press is certainly a milestone,” said Ralph McNutt, physicist and chief scientist for space science at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. “As more come out, it will be interesting to see what the turning point was that pushed this achievement beyond previous failed attempts,” he said.
McNutt said getting to a commercial power plant from this recent stage is likely to be a difficult task. “But the tortoise ended up beating the hare. Tenacity is always the virtue when dealing with difficult technical problems.”
When it comes to space exploration, it certainly doesn’t hurt to provide an example that great things can still be achieved, McNutt said.
“All that said, it should be a sobering thought that despite all the work on NERVA/Rover, there is still no working nuclear thermal rocket motor, and the promise of electric propulsion nuclear for space travel only had a brief glimmer with SNAP-10A in April 1965,” McNutt recalled.
Actual use of the ICF in a working spacecraft has been a long-held dream, McNutt said, but that’s very unlikely to change for a long time.
“Space travel has always been difficult. The fact that NASA ‘paved the way’ that many commercial entities are now following doesn’t mean space has gotten easier, but the new ICF results added to the ambitious glow on the horizon of the future,” McNutt added.
“That said, no one should be fooled into thinking that space will somehow not be tough one day. It’s called ‘rocket science’, with all that it entails in popular culture for a reason,” he concluded.
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