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Would you like to visit to Mars or move there?

Your answer might not be yes, but if it was, how would you do it?

The U.N.’s International Atomic Energy Agency (IAEA) said this week that nuclear power and related technologies “promise to make interplanetary missions faster, more efficient and economical.” The sweeping endorsement for nuclear power as a pivotal part of space exploration came from an international panel involving public and private sector experts. The panel, presented at a recent webinar was titled “Atoms for Space: Nuclear Systems for Space Exploration.”

With a worldwide pandemic, the outbreak of war in Europe and the general chaos of global warming, it seems outlandish to embrace the idea that scientists are still venturing their time, prestige and curiosity towards distant celestial opportunities. But the human imagination is hard to quell, to bottle up or snuff out.

“Nuclear technology has long played a vital role in prominent space missions,” said Mikhail Chudakov, IAEA Deputy Director General and Head of the Department of Nuclear Energy. “But future missions could rely on nuclear powered systems for a much broader spectrum of applications. Our pathway to the stars runs through the atom.”

Webinar participants heard about systems that can use both fission and fusion for spacecraft propulsion, extra-terrestrial surface power and power for onboard spaceship systems.

Once we dreamed only of getter there. Now, scientists are sending up rovers and you all know how that goes: Where there are rovers, someday someone’s going to want a parking space.

As such, NASA and the IAEA are anticipating “extra-terrestrial surface power.”

“Nuclear reactors could also be used to provide astronauts with a reliable source of surface power for extended exploration missions and a possible sustained human presence on other planetary bodies, supplying power for decades without need for refuelling. Fission surface power reactor designs are microreactors that could provide electrical power in the range of tens of kW for a period spanning from one to a few decades. The current focus is on using low enriched uranium fuels or high-assay low enriched uranium fuels,” the IAEA said.

“Crewed interplanetary missions of the future will almost certainly require propulsion systems with performance levels greatly exceeding that of today’s best chemical engines,” said William Emrich, former Lead Project Engineer at NASA, adding that a solid candidate to be used for space travel is nuclear thermal propulsion (NTP).

In NTP, a nuclear fission reactor heats up a liquid propellant, like hydrogen. The heat converts the liquid into a gas, which expands through a nozzle to provide thrust and propel a spacecraft. The advantages of NTP are that space flights would need to lift less fuel into space, and NTP engines would reduce trip times – cutting travel time to Mars by up to 25 per cent compared traditional chemical rockets. Reduced time in space also reduces astronauts’ exposure to cosmic radiation.

Nuclear electric propulsion (NEP), on the other hand, is an option in which the thrust is provided by converting the thermal energy from a nuclear reactor into electrical energy, eliminating the associated NTP needs and limitations of storing propellants onboard. In NEP, the thrust is lower but continuous, and the fuel efficiency far greater, resulting in a higher speed and potentially over 60 per cent reduction in transit time to Mars compared to traditional chemical rockets.

“For space missions that need high electric power output, such as a human Mars mission or space ferries, a fission reactor-based power system can be a very competitive choice,” said *** Du of the Beijing Institute of Spacecraft System Engineering, citing a China Academy of Space Technology study in 2015, which found that a human Mars mission would not be feasible without space nuclear reactors.

An NEP system being developed by Ad Astra Rocket Company, the Variable Specific Impulse Magnetoplasma Rocket (VASIMR), is a plasma rocket in which electric fields heat and accelerate a propellant, forming a plasma, and magnetic fields direct the plasma in the proper direction as it is ejected from the engine, creating thrust for the spacecraft. Unlike traditional NEP, the VASIMR design would enable the processing of large amounts of power while retaining the high fuel efficiency that characterizes electric rockets.

“In the near term, we envision the VASIMR engine supporting a wide array of high-power applications from solar electric in cislunar space, to nuclear-electric in interplanetary space,” said Franklin Chang Díaz, CEO of Ad Astra Rocket Company. “On a longer term, the VASIMR could be a precursor to future fusion rockets still in the conceptual stage,” he added.

Fusion rockets, like the Princeton Field Reversed Configuration reactor concept under development at the Princeton Plasma Physics Laboratory, would have the advantage of producing a direct fusion drive (DFD), directly converting the energy of the charged particles produced in the fusion reactions into propulsion for the spacecraft.

“A DFD can produce specific power several orders of magnitude higher than other systems, reducing trip times and increasing payloads, thus enabling us to reach deep space destinations much faster,” said Stephanie Thomas, Vice President of Princeton Satellite Systems, who discussed possible DFD-powered missions into near-interstellar space, human Mars missions and lunar base surface power. She also explained that a DFD could have the advantages of its small size and the need for very little fuel – a few kilograms could power a spacecraft for ten years.