SMART-1's Ion Drive Not Science Fiction

SMART-1, the European Space Agency craft currently in orbit around the moon, makes use of a technology that was pure science fiction until almost 1960 - the ion drive. An ion drive is a method of propulsion that uses electricity to create charged ions and then accelerate them with a magnetic field, pushing them out the rear of a spacecraft.

The ion drive was first described in science fiction in 1947 by Jack Williamson in a short story published in Astounding Science Fiction called "The Equalizer." In the story, the spacecraft achieves a significant fraction of the speed of light, returning decades later due to time dilation, using an ion thruster.

George Lucas makes use of ion drives in Star Wars: the old Empire makes use of T.I.E. Fighters as small, manuverable spacecraft. T.I.E. is an acronym for Twin Ion Engines:

The hexagonal solar panels supply power to a unique propulsion system. Microparticle accelerators propel Ionized gasses at a substantial fraction of lightspeed...
(Read more about T.I.E. Fighters)

US astronaut Edward Gibson published Reach in 1989; this novel features a spacecraft with an ion drive that accelerates atoms of mercury to one percent of the speed of light before sending them out the rear of the craft.

SMART-1 has a stationary plasma thruster using xenon gas with 1190 watts of power available, giving a nominal thrust of 68 mN. The spacecraft contains 48 liters of xenon gas at 150 bar. The lifetime of the thruster is 7,000 hours at maximum power. The thrust is equivalent to two pennies resting in the palm of your hand.


(From SMART-1 Ion Drive)

If this seems like a propulsion system that is a bit short of "warp speed," you're right. However, in the frictionless environment of space, even a gentle acceleration like this can produce real velocity if applied constantly over a long enough period of time. Take a look at the path of SMART-1 as it gradually increased its speed, spiralling further and further from Earth before breaking free of Earth's gravity and heading toward the moon. Since a solar panel-equipped ion drive craft only carries the weight of the propellant, and can eject the propellant at significantly greater velocity, such a craft will outperform a spacecraft that uses conventional chemical propulsion over the long run. (Chemical propulsion depends on carrying the weight of the reactant chemical; the exhaust velocity is also significantly less.)


(From SMART-1 Orbital Path)

The US probe Deep Space 1 also used an ion drive, succeeding in its dual missions of flybys of asteroid Braille and Comet Borrelly in 1999. Ion drives have been used in satellites as a way of gently nudging them into higer orbits; the Irridium satellite network made use of ion drive propulsion for positioning and to prevent orbit decay.

SMART 1 has traveled a total of 80 million kilometers in 13 months to reach the moon (due to its spiraling path); Apollo 11 traveled 400,000 kilometers in four days during the first Moon landing mission. On the other hand, the washing machine-sized SMART 1 cost just $85 million.

The early history of the idea of accelerating particles electrically as a means of propulsion goes back as early as 1906, when American scientist Dr. Robert Goddard mentioned the possiblity in his research into rocketry. Dr. Hermann Oberth, a German engineer, introduced Dr. Wernher von Braun to the possibility in the 1930's, and published Possibilities of Space Flight in 1939, devoting a chapter to electric propulsion methods. It was Dr. von Braun who eventually talked NASA into working on a prototype, saying "I wouldn't be a bit surprised if we flew to Mars electrically." The basic principles of the ion drive were tested as early as 1959 at NASA's Glen Research Center; the first working drive was created in 1970. Deep Space 1, launched in 1998, was the first ion drive craft sent into space (read the final technical evaluation of its propulsion system).

The European Space Agency has a very nice website about SMART-1; along with mission objectives and updates, it includes a set of articles about electric spacecraft propulsion. You'll also find some information about ion drives and other science-fictional technologies in the short book Innovative Technologies from Science Fiction. Thanks to David Raitt for pointing these out. See also the comprehensive article Ion propulsion - over 50 years in the making.

Scroll down for more stories in the same category. (Story submitted 11/18/2004)

Follow this kind of news
@Technovelgy.

| Email | RSS | Blog It | Stumble | del.icio.us | Digg | Reddit |

Would you like to contribute a story tip? It's easy:
Get the URL of the story, and the related sf author, and add it here.

Comment/Join discussion ( 3 )

Related News Stories - (" Space Tech ")

How Do You Put An Asteroid Into Earth Orbit? Carefully!
'...she would have to be coaxed by another series of pats into a circular orbit.' - Robert Heinlein, 1939.

PD Aerospace Space Plane By 2023
'The sleek, tapered space shuttle lay immobile upon the private landing field...' - Frederic Arnold Kummer, Jr., 1940.

International Space Station Leak Plugged - With Finger
'These tag-alongs search out stray leaks' - Robert Heinlein, 1948.

Space Drones - UK's Effective Space To Launch Rocket Tugs
'Twenty rocket tugs towed it from its Earth hangar out into space.' - Nat Schachner, 1937.

 

Google
  Web TechNovelgy.com   

Technovelgy (that's tech-novel-gee!) is devoted to the creative science inventions and ideas of sf authors. Look for the Invention Category that interests you, the Glossary, the Invention Timeline, or see what's New.

 

 

 

 

 

Current News

Sleeep PRO Earplug For Maximum Rest
'Merton... placed the electrodes of the sleep-inducer on his forehead.'

Inspired By Japan, Nap Pods For Hajj
It's always a good time for a nap.

Amphibio 3D Printed Gill Shirt
'... we can descend and live down there at one of those year-round aquatic resorts.'

How Do You Put An Asteroid Into Earth Orbit? Carefully!
'...she would have to be coaxed by another series of pats into a circular orbit.'

PD Aerospace Space Plane By 2023
'The sleek, tapered space shuttle lay immobile upon the private landing field...'

Foldimate Folds Your Clothes Perfectly
Look ma, my room is clean! I can hear you now.

Robots Help People Get Dressed, As Predicted In 1931
Yes, people of the future, robots will dress you.

International Space Station Leak Plugged - With Finger
'These tag-alongs search out stray leaks.'

Robot Snake Flies, Fights Fires
Just a prototype, but still amazing.

IPAL Chinese Robot Babysitter
'But Nanny is different...'

ZKZM-500 LASER Assault Rifle
'The Iranian reached back into the locker and got a pair of laserifles.'

LA Subway Scanner, As Seen In 'Total Recall'
'I'm afraid to tell you this Mr. Quaid, but you have suffered a schizoed embolism...'

Sion Electric Car Covered With Solar Panels
'It drew its power from six square yards of sunpower screens on its low curved roof.'

PAL-V Liberty Flying Helicopter Car
'...lifted themselves to skimming flight upon whirling helicopters."

Space Drones - UK's Effective Space To Launch Rocket Tugs
'Twenty rocket tugs towed it from its Earth hangar out into space.'

DIY Autonomous Robot Detects Trash
'The search-bug detached itself and rolled forward.'

More SF in the News Stories

More Beyond Technovelgy science news stories

Home | Glossary | Invention Timeline | Category | New | Contact Us | FAQ | Advertise |
Technovelgy.com - where science meets fiction™

Copyright© Technovelgy LLC; all rights reserved.