NASA reveals record-setting tests of radical ion engine that could take man to Mars

  • Hall Thruster uses electric and magnetic fields to produce thrust
  • Cleaner, safer and more fuel efficient than traditional chemical rockets  

Engineers from NASA and the University of Michigan have revealed record breaking tests of a radical ion engine designed to get man to Mars.

Known as a Hall Thruster, it is one of three Mars engine prototypes currently in development, and uses electric and magnetic fields to ionize gases like xenon and expels the ions to produce thrust.

The technique is much cleaner, safer and more fuel efficient than traditional chemical rockets, but the trade off is relatively low thrust and acceleration.

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A prototype ion engine in use: The core technology – the Hall thruster – is already in use for manoeuvring satellites in orbit around the Earth

A side shot of the X3 firing at a record-breaking 50 kilowatts. The Hall Thruster is one of three Mars engine prototypes currently in development

HOW DO HALL THRUSTERS WORK? 

A Hall thruster works by accelerating the plasma exhaust to extremely high speeds.

The process starts with a current of electrons spiraling through a circular channel.

On their whirlwind journey from the negative electrode at the exhaust end to the positively charged electrode on the inner side of the channel, they run into atoms (typically xenon gas) that are fed into the chamber.

The collisions knock electrons off the xenon atoms and turn the xenon into positively charged ions.

The electrons' spiraling motion also builds a powerful electric field that pulls the gas ions out the exhaust end of the channel, creating thrust. 

Just enough electrons leave with the ions to keep the spacecraft from accumulating a charge, which could otherwise cause electrical problems.

 

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'Mars missions are just on the horizon, and we already know that Hall thrusters work well in space,' says Alec Gallimore, lead engineer on the X3's development. 

'They can be optimized either for carrying equipment with minimal energy and propellant over the course of a year or so, or for speed — carrying the crew to Mars much more quickly.'

Some experts have said the engines could take man to Mars in weeks, rather than years.

In the recent tests, the X3 broke three different records previously set by other Hall thrusters, a very promising step towards manned Mars missions.

The development of the thruster was led by Alec Gallimore, University of Michigan professor of aerospace engineering and the Robert J. Vlasic Dean of Engineering.

Hall thrusters offer exceptionally efficient plasma-based spacecraft propulsion by accelerating small amounts of propellant very quickly using electric and magnetic fields. They can achieve top speeds with a tiny fraction of the fuel required in a chemical rocket. 

The challenge is to make them larger and more powerful. 

The X3, a Hall thruster designed by researchers at U-M, NASA and the U.S. Air Force, shattered the previous thrust record set by a Hall thruster, coming in at 5.4 newtons of force compared with 3.3 newtons. 

The improvement in thrust is especially important for crewed mission—it means faster acceleration and shorter travel times. 

The X3 also more than doubled the operating current record (250 amperes vs. 112 amperes) and ran at a slightly higher power (102 kilowatts vs. 98 kilowatts).

Researcher Scott Hall makes some final adjustments on the thruster before the test begins

Researcher Scott Hall makes some final adjustments on the thruster before the test begins

The X3 is one of three prototype 'Mars engines' to be turned into a full propulsion system with funding from NASA. 

Scott Hall, a doctoral student in aerospace engineering at U-M, carried out the tests at the NASA Glenn Research Center in Cleveland, along with Hani Kamhawi, a NASA Glenn research scientist who has been heavily involved in the development of the X3. 

The experiments were the culmination of more than five years of building, testing and improving the thruster.

HAS CHINA CRACKED THE 'IMPOSSIBLE ENGINE'?

A new propaganda video claims that scientists in China have created a working prototype of the 'impossible' fuel-free engine.

The radical EmDrive has been hypothesised for years by Nasa, but the space agency has been unable to create a working version.

If the physics-defying concept is brought to reality, it's said the engine could get humans to Mars in just 10 weeks.

The video was posted by CCTV.com, and is titled 'Propellantless propulsion: The Chinese EmDrive by CAST scientist Dr Chen Yue, China's Space Agency.'

It claims that Chinese scientists have developed the EmDrive, and will soon put it into space - although it does not state any technical aspects of the device.

The EmDrive is an engine that provides thrust without the need for fuel.

Instead, it bounces microwaves - provided by solar energy - around in a closed container.

With no fuel to eject, the EmDrive would violate Newton's third law, which states that for every action, there is an equal and opposite reaction.

This isn't the first time that China has claimed to have made a working EmDrive.

 

 

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NASA Glenn, which specializes in solar electric propulsion, is currently home to the only vacuum chamber in the U.S. that can handle the X3 thruster. 

The thruster produces so much exhaust that vacuum pumps at other chambers can't keep up. 

Then, xenon that has been shot out the back of the engine can drift back into the plasma plume, muddying the results.  

Hall built a custom thrust stand to bear the X3's 500-pound weight and withstand its force, as existing stands would collapse under it. 

'The big moment is when you close the door and pump down the chamber,' Hall said.

If I had to predict, I would say this thruster would be the basis for sending humans to Mars.

After the 20 hours of pumping to achieve a space-like vacuum, Hall and Kamhawi spent 12-hour days testing the X3.

Next the X3 will at last be integrated with the power supplies under development by Aerojet Rocketdyne, a rocket and missile propulsion manufacturer and lead on the propulsion system grant from NASA. 

In spring 2018, Hall expects to be back at NASA Glenn running a 100-hour test of the X3 with Aerojet Rocketdyne's power processing system. 

 Because it uses less fuel than conventional chemical rockets, the thruster is ideal for exploring Mars, asteroids and the edge of the solar system. 

Nasa wants to send humans to an asteroid by 2025 and Mars in the 2030s In a step towards that goal, the space agency is funding plasma engines that could propel astronauts to the red planet on much less fuel. The tabletop-sized thruster prototype, dubbed the 'X3,' uses a 45,000 mph stream of plasma to push craft forward

Nasa wants to send humans to an asteroid by 2025 and Mars in the 2030s In a step towards that goal, the space agency is funding plasma engines that could propel astronauts to the red planet on much less fuel. The tabletop-sized thruster prototype, dubbed the 'X3,' uses a 45,000 mph stream of plasma to push craft forward

The prototypes have been created by engineers from the University of Michigan's Next Space Technologies for Exploration Partnerships (NextSTEP) program.

The engine is part of Aerojet Rocketdyne's XR-100 propulsion system, which could, in the next ten years propel a vessel to Mars.

Nasa awarded $6.5 million over the next three years to Aerojet Rocketdyne for the development of the propulsion system, dubbed the XR-100.

Developed by Professor Alec Gallimore thruster, the X3, is central to this system, and his team will receive $1 million of the award for work on the thruster.

The XR-100 is up against two competing designs.

All three of them rely on ejecting plasma – an energetic state of matter in which electrons and charged atoms called ions coexist – out the back of the thruster. 

The core technology – the Hall thruster – is already in use for manoeuvring satellites in orbit around the Earth.

'For comparison, the most powerful Hall thruster in orbit right now is 4.5 kilowatts,' said Gallimore.

That's enough to adjust the orbit or orientation of a satellite, but it's too little power to move the massive amounts of cargo needed to support human exploration of deep space.

A Hall thruster works by accelerating the plasma exhaust to extremely high speeds.

The core technology – the Hall thruster (right) – is already in use for manoeuvring satellites in orbit around the Earth. A Hall thruster works by accelerating the plasma exhaust to extremely high speeds
The core technology – the Hall thruster (right) – is already in use for manoeuvring satellites in orbit around the Earth. A Hall thruster works by accelerating the plasma exhaust to extremely high speeds

The core technology – the Hall thruster (right) – is already in use for manoeuvring satellites in orbit around the Earth. A Hall thruster works by accelerating the plasma exhaust to extremely high speeds

Because its consumes 100 million times less fuel than conventional chemical rockets, the thruster is ideal for exploring Mars, asteroids and the edge of the solar system

Because its consumes 100 million times less fuel than conventional chemical rockets, the thruster is ideal for exploring Mars, asteroids and the edge of the solar system

The process starts with a current of electrons spiraling through a circular channel.

On their whirlwind journey from the negative electrode at the exhaust end to the positively charged electrode on the inner side of the channel, they run into atoms (typically xenon gas) that are fed into the chamber.

The collisions knock electrons off the xenon atoms and turn the xenon into positively charged ions.

The electrons' spiraling motion also builds a powerful electric field that pulls the gas ions out the exhaust end of the channel.

Just enough electrons leave with the ions to keep the spacecraft from accumulating a charge, which could otherwise cause electrical problems.

'When they're ionized, the xenon atoms can shoot out at up to 30,000 meters per second, which is about 65,000 mph,' said Gallimore.

The X3 contains three of plasma channels, each a few centimeters deep, nested around one another in concentric rings. The nesting is what allows the Hall thruster to operate at 200 kilowatts of power in a relatively small footprint

The X3 contains three of plasma channels, each a few centimeters deep, nested around one another in concentric rings. The nesting is what allows the Hall thruster to operate at 200 kilowatts of power in a relatively small footprint

The X3 contains three of these channels, each a few centimeters deep, nested around one another in concentric rings.

The nesting is what allows the Hall thruster to operate at 200 kilowatts of power in a relatively small footprint.

Scott Hall, a doctoral student in Professor Gallimore's lab, will use the funding to put the X3 through a battery of tests. 

He will first run it up to 60 kilowatts in the Plasmadynamics and Electric Propulsion Lab at U-M and then up to 200 kilowatts at the Nasa Glenn Research Center in Cleveland, Ohio

Meanwhile, another doctoral student, Sarah Cusson, will investigate a tweak that could allow the X3 to remain operational for five to ten times longer than its current lifetime of a little over a year.

NASA USES LASERS TO PRODUCE THRUST

Hall thrusters aren't the only technology that Nasa is betting on to take humans to Mars. 

Technology harnessing the power of light could be the key to cutting down travel times to Mars from years to just a matter of days.

In a separate project, a group of physicists in California is working on probe that could lead to technology to get to Mars at much faster speeds than is currently possible.

The answer to doing this could lie in what's known as photonic propulsion, a technique that uses light from lasers to produce thrust to drive spacecraft.

While the technology the team is creating will be targeted at extremely small probes, someday it could inspire the creation of larger spacecraft that travel rapidly to Mars.

A group of physicists in California is working on spacecraft that could let humans reach the nearest stars in our solar system - a challenge that is not possible with current propulsion technology. The answer could lie in what's known as photonic propulsion, a technique that uses light from lasers to produce thrust (illustrated)

A group of physicists in California is working on spacecraft that could let humans reach the nearest stars in our solar system - a challenge that is not possible with current propulsion technology. The answer could lie in what's known as photonic propulsion, a technique that uses light from lasers to produce thrust (illustrated)

Professor Phillip Lubin and his team from the University of California Santa Barbara are working on the Directed Energy Interstellar Precursors (Deep-In) programme. 

The programme aims to create probes capable of reaching relativistic speeds and travelling to the nearest stars. 

A relativistic speed is a speed which is a significant proportion of the speed of light. 

'We know how to get to relativistic speeds in the lab, we do it all the time,' said Lubin at Nasa's National Innovative Advanced Concepts (Niac) symposium.

'When we go to the macroscopic level, things like aircraft, cars, spacecraft, were pathetically slow.'

Professor Lubin is aiming to bridge the gap between the small and the large, using photonic propulsion technology.  

The theory is simple; thrust from photons emitted from a laser array could be used to propel a spacecraft.

All spacecraft operate by firing propellant in the opposite direction to the way they want to travel. Traditionally this propellant is fuel. Photonic propulsion uses an array of lasers instead, which means no fuel needs to be carried on the spacecraft (illustrated)

All spacecraft operate by firing propellant in the opposite direction to the way they want to travel. Traditionally this propellant is fuel. Photonic propulsion uses an array of lasers instead, which means no fuel needs to be carried on the spacecraft (illustrated)

All spacecrafts operate by firing their propellant in the opposite direction to the way they want to travel.

Traditionally this propellant is fuel and has to be carried on board the spacecraft, making it heavier and slowing it down.

Photonic propulsion uses an array of lasers instead, which adds no mass to the spacecraft other than the laser itself. 

This enables it to accelerate for longer and reach higher speeds. n theory, this should help get aircraft to relativistic speeds. 

Professor Lubin didn't specify what proportion of the speed of light the technology would reach, although he did say it could be up to a quarter. 

The launch into orbit would also be slower at the start and during the descent, for example.

As a result, the professor said: 'We could propel a 100kg aircraft to Mars in a few days. In comparison it would take a shuttle roughly a month to get there,' the researchers said.

 

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'If we do our jobs over the next three years, we can deliver both projects,' said Gallimore.

'If I had to predict, I would say this thruster would be the basis for sending humans to Mars.' 

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