Space Flight Archives

February 26, 2008December 26, 2015 by Ian O'Neill

“Foresight” Wins First Prize in Apophis Asteroid Tagging Competition

The Near Earth Asteroid (NEO) Apophis is expected to flyby the Earth in 2029. However, this flyby will be more of a “fly-very-close” as the lump of rock will miss the Earth by only a few thousand kilometers. This near-miss isn’t worrying scientists too much, but should the asteroid tumble through a 400 meter gravitational “keyhole”, there is concern that the asteroid could swing by and risk another collision in 2036. Although the odds are fairly slim, astronomers need better precision in calculating Apopis’s orbital trajectory.

How can this be done? Why not send a spaceship to shadow the asteroid on its journey? The Planetary Society has announced just that. The winning design of the Apophis Mission Design Competition will send a probe and tag Apophis to gain more details about this interplanetary vagabond, and has been awarded a healthy $25,000 to help the development of the US “Foresight” mission…

99942 Apophis (otherwise known as asteroid 2004 MN4) caused quite a stir back in 2004 when it was discovered. Lacking detailed observation at the time, the probability of the 270 meter long piece of rock hitting the Earth was around 2.7% – a large risk in astronomical terms. Now we are sure the asteroid will fly straight by, albeit rather close. It is estimated that Apophis will pass within the orbit of geostationary satellites located at 35,786 km above Earth, allowing amateur astronomers a great opportunity to observe the NEO (it will be possible to see the asteroid with the naked eye at night), whilst being secure in the knowledge that it’s not going to come any closer.

So, panic over? Not quite. Although Apophis will miss us on its first approach in 2029, we might not be so lucky on one of its return trips in 2036. During its flyby in 2029, should the asteroid pass through a critical gravitational “keyhole” measuring only 400 meters across, the gravitational deflection applied to the Apophis asteroid may adjust its orbit, setting it up for a collision course with Earth seven years later.

This is the reason for events such as the Planetary Society’s Apophis Mission Design Competition, to raise awareness of the risk posed by NEOs. Although the winning entry, designed by SpaceWorks Engineering Inc. (Atlanta, Georgia) in conjunction with SpaceDev Inc. (Poway, California), is in the design phase, it is hoped that the completed project could launch by 2012. “Foresight” is intended to fly to Apophis and tag the rock with tracking equipment. The orbiter will continue to study the asteroid and follow it on its orbit around the Sun, gathering valuable information about its composition, center of mass, surface features and, most importantly, its trajectory.

Missions plans such as Foresight are required by the international community to be used should the threat of an asteroid collision become reality (and not remain in cheesy sci-fi movies like Deep Impact or Armageddon).

“Apophis isn’t science fiction, it isn’t a blockbuster Hollywood movie; it is very real.” – Dan Geraci, the Planetary Society’s board chairman.

For more information on the winning entry and the other award winning designs, see the Planetary Society’s Apophis Mission Design Competition website.

February 24, 2008April 26, 2016 by Ian O'Neill

Space Debris May be Catastrophic to Future Missions (and Google Earth is Watching…)

Kessler Syndrome could be a frightening situation for space travel. No, it’s not a health risk to the human body in zero-G and it’s not a psychological disorder for astronauts spending too much time from home. Kessler Syndrome is the point at which space travel becomes impossible without hitting into a piece of space junk, jeopardizing missions and risking lives. In extreme predictions, space debris from our constant littering of low Earth orbit, collisions between bits of rubbish may become more and more frequent, causing a catastrophic cascade of debris multiplying exponentially, falling through the atmosphere and making space impassable.

In the meanwhile, space mission controllers must be acutely aware that there could be an odd bolt or piece of old satellite flying toward their spaceship at velocities faster than the fastest rifle shot. Spare a thought for the space debris trackers as they try to keep a record of the 9,000+ pieces of junk currently orbiting our planet… but wait a minute, Google Earth can give us a ringside seat!

Strict international civil aviation-style laws may need to be imposed on the worlds space agencies if future generations of the human race are going to make it in space. This stark warning comes from Tommaso Sgobba, Director of the International Association for the Advancement of Space Safety, who will be presenting his case to the United Nations in April. Sgobba’s main argument comes from the danger associated with the escalating accumulation of space debris in Earth orbit, should these high speed bits of junk hit a spaceship, satellite or an astronaut, death and disaster may ensue. It may get worse than this, possibly paralysing the Earth from having access to space at all.

“Failure to act now to regulate space to protect property and human life would be pure folly.” – Tommaso Sgobba.

Other scientists agree with Sgobba, recommending that future missions in to space abide by some strict codes of practice (possibly more strict than those imposed on international civil aviation) to drastically cut the rate of orbital littering by the 20 countries currently able to send stuff into space.

Even the most tightly controlled missions, such as the International Space Station, are expected to shed bits and pieces over the course of their lifetimes. Space junk comes in all shapes and sizes and can be anything from a small screw to entire dead satellites. Recorded examples of space junk include an old glove lost by Ed White during the first ever US space walk in 1965 (during the Gemini-4 mission), a camera that Michael Collins let slip in space in 1966 (during the Gemini-8 mission) and a pair of pliers that International Space Station astronaut Scott Parazynski dropped during an EVA last year.

Some space debris near misses include:

Space Shuttle dodge: Space Shuttle Atlantis had to avoid collision with a piece of a Russian satellite by carrying out a seven second burn of its engines in 1991.
Aircraft scare: Bits of an Russian ex-spy satellite fell through the atmosphere coming very close to a Latin American Airbus, carrying 270 passengers in 2006.
Personal injury: fortunately there is only one documented account of someone being hit by a piece of debris on the ground. In 1997 a woman from Oklahoma was hit on the shoulder by a piece of a fuel tank from a Delta II rocket. She was unhurt and lived to tell the tail.

It is hoped that tighter controls on the rockets, satellites and spacecraft will slow the rate of junk increase, but the problem is already pretty worrying for long-term missions in orbit around the Earth. The two critical regions filling with debris are in low Earth and geosynchronous orbits, a few hundred and 22,300 miles high respectively. Low Earth orbit will cause problems for spacecraft to actually leave the atmosphere and geosynchronous orbit may hinder future communication satellite insertions.

To safeguard our access into space, and avoid an increase in debris-related incidents, action will need to be taken.

Google Earth-watch

During the research on this article, I came across some work being funded by Ministry of Culture of the Republic of Slovenia, Municipality of Ljubljana, where researchers are making debris location data available to the public via a plugin for the Google Earth application. According to the groups blog, the data is taken from a U.S. government-owned space observatory so known space debris (or as the blog calls it “pollution”, which it really is) can be tracked.

On experimenting with the new space debris folder, it really did strike home as to what a problem space junk is becoming. For starters, there is an impossibly thick near-Earth layer and a distinct ring representing the geosynchronous debris. Plus, each item can be selected and information on the individual bits of debris can be found out… see the screenshots to find out what I mean…

Get the space junk plugin for Google Earth (read Google Earth documentation to learn how to use this plugin).

News Source: Guardian.co.uk

February 18, 2008December 26, 2015 by Nancy Atkinson

Shuttle Crew Says Goodbye, Undocks from ISS

212265main_image_1021_800-600.thumbnail.jpg

After a successful visit to the International Space Station, the crew of space shuttle Atlantis said farewell and undocked from the station at 4:24 am EST Monday morning. Their busy nine-day stay included three spacewalks and the installation of the European Columbus science module, as well as a switch-out in crew. European astronaut Leopold Eyharts stays on the ISS while US astronaut Dan Tani returns home after a four-month expedition on the station.

“We just wanted to thank you again for being a great host and letting us enjoy your station for about a week,” shuttle commander Steve Frick radioed to the ISS before undocking. “We had a great time over there, we learned a lot and we really, really enjoyed working with your crew, one quarter of which we have here and we’re happy to take Dan home. But just again, to you and to Yuri and to Leo, thanks very much.”

“Well thank you guys,” station commander Peggy Whitson replied. “Itâ€™s a great new room you’ve added on and we really appreciate it. Get Dan home safe, and thanks!”

In an emotional farewell ceremony on Sunday, Tani reflected on his extended mission. The delay of Atlantis’ mission due to fuel sensor problems made his stay in space almost two months longer than originally planned. During his time on the station, Tani’s mother, who he called his “inspiration” was killed in a car accident. He said he can’t wait to get back home to be with his family.

But his recent experiences have given him great hope for the future.

“Today I feel very optimistic about our space program and our society because I’m here, I’ve spent time with a man from France, from Italy and from Germany and from Russia,” he said. “Nations that have not always been friendly are now cooperating and we’re doing great things.”

With shuttle pilot Alan Poindexter at the controls, the shuttle did a one-loop fly around of the station before departing. Atlantis’ crew is inspecting the shuttle’s heat shield to get the final OK for landing, which is scheduled for shortly after 9:00 am Wednesday morning, if the weather holds in Florida. Both the Kennedy Space Center and the backup landing site in California will be ready as NASA wants the shuttle to land that day to give the military enough time to destroy a damaged spy satellite.

The next shuttle flight is coming right up. Endeavour began its crawl to the launch pad early Monday in to prepare for a March 11 liftoff.

North American residents with clear skies Monday evening should be able to see both Atlantis and the ISS flying in tandem. See NASAâ€™s orbital tracking site or Heavenâ€™s Above for sighting times for your area.

February 5, 2008December 26, 2015 by Ian O'Neill

British Engineers Design Hypersonic Passenger Jet

A British engineering company has stepped into the commercial spaceflight arena with an ambitious and inspiring design of a possible airliner of the future. The A2, the design behind the Long-Term Advanced Propulsion Concepts and Technologies (LAPCAT) project, will carry 300 passengers, will have a range of 20,000 km and will be capable of travelling twice the speed of Concorde – that’s a sustained velocity of Mach 5. It will also be capable of atmospheric and space flight leading to the exciting possibility of becoming a large vehicle shuttling passengers, astronauts and payloads into orbit…

As private enterprise is beginning to see the possibility of profit in spaceflight, more and more rocket, spaceship and aircraft designs are being realised beyond the realms of science fiction. Richard Branson’s Virgin GalacticÂ and Elon Musk’s SpaceXÂ bear testament to the opportunities that await commercial transport into space. While Branson’s SpaceShipTwo concept uses a conventional WhiteKnight aircraft to “piggyback” until a maximum altitude is reached before it’s rocket engines propel it into space, Musk’s program depends on the ballistic approach, sending his Falcon rocket into space via a conventional rocket launchpad. The A2 concept is different as it will take off and land like a passenger jet without the need to be helped on its way by another aircraft.

The A2 is an impressive looking craft, and the claim that it may be able to sustain hypersonic flight is impressive. Currently, only astronauts leaving or re-entering the atmosphere travel at hyper sonic velocities, no aircraft is capable of such speeds within the Earth’s atmosphere. Mach 5 is the speed at which large amounts of heating occurs on an aircraft’s body, temperatures in excess of 1,800Â° F (1,000Â° C), so the engineering of hypersonic aircraft must be sufficiently advanced to protect passengers and aircraft structure from this extreme environment.

The A2 is intended to travel at Mach 5 within the atmosphere so it can enter low Earth orbit, giving it the ability to carry out orbital tasks as well as travelling to international destinations very quickly. It is hoped the A2 will travel from Europe to Australia within four hours. Reaction Engines Ltd. project the A2 will be in full production within 25 years.

The A2 will be able to do this through the use of Scimitar Engines – fueled by huge amounts of hydrogen (indeed, most of the aircraft fuselage will contain the fuel to feed theÂ four engines slung under its wings) – that are designed around existing gas turbine, rocket and subsonic ramjet technology.

See more about the A2 design at Reaction Engines Ltd.

Source: BBC

February 1, 2008December 26, 2015 by Nancy Atkinson

Memorial Service Honors Columbia Astronauts

Five years ago, family members of the STS-107 space shuttle crew were waiting at the Kennedy Space Center to hear the double sonic boom that would announce the arrival of the Columbia shuttle returning home from its mission to space. But the sonic booms never came; there was only silence. Today, at the Space Mirror Memorial at the NASA Kennedy Space Center, NASA officials, astronauts and families of the Columbia crew paid tribute to all astronauts who have lost their lives, and called for NASA to continue to learn from the tragedies.

Evelyn Husband Thompson, wife of STS-107 commander Rick Husband said that each of the families are recalling what they went through five years ago in public or private ways. Families of Ilan Ramon and Willie McCool are in Israel for a memorial service there, while the families of Dave Brown, Laurel Clark, Mike Anderson and Kalpana Chawla are privately remembering the accident.

The astronauts were returning home from a successful flight when the shuttle broke up on re-entry.

Husband-Thompson, who remarried just three weeks ago said, “Life does go on, and even though we never know what life is going to bring us, there is hope for tomorrow.”

Eileen Collins, who commanded the STS-114 return to flight mission two years after the Columbia accident said that, personally, this was a difficult day for her, and that it was hard to describe the experiences of the past five years.

“I can’t properly put it into words, but our purpose here today is to honor and respect, remember and learn,” she said. Collins said that she has changed because of the accident, and now realizes that spaceflight is even more difficult and hazardous than she originally believed.

“Everyday requires constant attention to detail,” she said.

Remembering the crews of Columbia, Challenger, and Apollo 1, NASA Associate Administrator for Space Operations Bill Gerstenmaier said, “All astronauts who have sacrificed their lives are pioneers and role models who refused to shy away from seemingly impossible challenges.”

Gerstenmaier spoke frankly about loss and NASA’s mistakes.

“This is a tough time of year for our agency as we pause and remember the loss of our co-workers and friends, and the failure of our engineering design. We feel the deep ache of regret,” he said. “Our memories serve to dedicate ourselves to reducing the risks associated with the hostile environment in which we fly. We must continually challenge our assumptions and test our designs. Only with this attitude can we hope to not be surprised by another tragedy.”

NASA Adminstrator Mike Griffin said, “American’s don’t quit. We’ll never quit. But today we remind ourselves that not quiting can have high costs. Today, we celebrate the people who bore those costs and the people who remain behind them. We don’t forget, we never forget, we can’t forget, we won’t forget.”

Original News Source: NASA TV

January 31, 2008December 26, 2015 by Nancy Atkinson

50 Years Ago: Explorer 1

The launch of Sputnik in October 1957 changed the world overnight. And with the Soviet Union’s second successful launch of Sputnik 2 the following month, Americans were feeling a little left behind in the dust, especially after the US’s first satellite launch attempt with the Vanguard rocket exploded on the launchpad. But space pioneer Werner Von Braun, shown in this picture with JPL Director William Pickering and scientist James Van Allen, came through with his Jupiter C rocket that launched the US’s first satellite, Explorer 1, into space on January 31, 1958.

Explorer 1 was not all that big, with a length of 203 centimeters (80 inches), a diameter of 15.9 centimeters (6.25 inches), and a weight of 14 kilograms (30.8 pounds). But it did its job, which was, first and foremost, to reach orbit, and then return scientific information.

The Jet Propulsion Laboratory got the assignment of designing and building a scientific payload for the launch, which they accomplished in three months.

The primary science instrument on Explorer 1 was a cosmic ray detector designed to measure the radiation above the atmosphere. Dr. James Van Allen designed the experiment, which revealed a much lower cosmic ray count than expected. Van Allen theorized that the instrument may have been saturated by very strong radiation from a belt of charged particles trapped in space by Earth’s magnetic field. A subsequent launch by Explorer 3 two months later confirmed the existence of these radiation belts, which became known as the Van Allen Belts, in honor of their discoverer.

There were other scientific findings from Explorer 1 as well. Because of its symmetrical shape, Explorer 1 was used to help determine the upper atmospheric densities.

Two other instruments on board looked for micrometeorites in orbit: a micrometeorite detector and an acoustic microphone to detect the sound of an micrometeorite impact. The micrometeorite detector was made of a grid of electrical wires. A micrometeorite of about 10 microns would fracture a wire upon impact, destroy the electrical connection, and record the event. One or two of the wires were destroyed during launch. The equipment worked for about 60 days, but showed only one possible meteorite impact. Data from the acoustical sensor microphone were obtained only when an impact occurred while the satellite was over a ground recording station. However, over an 11-day period (February 1, 1958, to February 12, 1958), 145 impacts were recorded. The high impact rates on one portion of the orbit and the subsequent failures in the satellite’s electronic system were attributed to a meteor shower.

The batteries ran out on Explorer 1 on May 23, 1958 when the last signal was recorded. The US’s first satellite burned up in re-entry of the atmosphere in March of 1970.

Original News Source: Explorer 1

January 27, 2008December 26, 2015 by Ian O'Neill

Scientists Designing “Ion Shield” To Protect Astronauts From Solar Wind

British scientists are working to build an invisible magnetic “Ion Shield” to be used during missions in space. A minature solar wind has been created in an Oxfordshire laboratory to simulate the highly charged particles emitted from the Sun and a magnetic “bubble” is being conceived to surround future spaceships. The magnetic field should have sufficient deflecting strength to redirect cancer-causing energetic particles away from future astronauts. Useful, especially during the proposed long-haul flights to Mars should the Sun begin launching flares at the wrong time…

The protection of astronauts in space from being bathed in damaging solar radiation is paramount to mission planners. Preventing exposure to high-energy particles is essential for the short-term success of the mission, and for the long-term health of the astronaut. Generally, humans in Earth orbit are protected from the ravages of the solar wind as they are within the protective blanket surrounding our planet. The protection is supplied by Earth’s magnetosphere, a powerful magnetic shield that deflects charged particles and channels them to the north and south poles, allowing life to thrive down here on the surface. The particles injected into the poles react with our atmosphere generating light, the Aurora.

So, the UK team are looking to create a small-scale “magnetosphere” of their own. If a spaceship can generate its own magnetic field, then perhaps the majority of solar particles can be deflected, creating a protective bubble the ship can travel in during solar storms. This may sound like science fiction, but the physics is sound, magnetic fields are used every day to deflect charged particles. Why not try to build a spaceship-sized magnetic particle deflector?

“We now have actual measurements that show a ‘hole’ in the solar wind could be created in which a spacecraft could sit, affording some protection from ‘ion storms’, as they would call them on Star Trek.” – Dr Ruth Bamford, physicist at the Rutherford Appleton Laboratory (RAL) in Chilton, Oxfordshire.

Firing a jet of charged particles into a strong magnetic field was attempted in the laboratory and the results were excellent. Observing the particles “hit” the leading edge of the field, a protected volume was made within the synthetic solar wind, arcing the particles around the void.

These are very early results however, and development on any large-scale system will take some work. Lots of energy would be required to create a spaceship-sized magnetic bubble, so there will be energy optimization issues to work into the design. Whether this exciting form of protection is possible or not, the pressure will be on to build a prototype before plans for the international Global Exploration Strategy to send man back to the Moon and beyond come into action. The US is now committed to a manned mission to Mars by 2020, so it would be useful to have the solar wind, high-energy particle problem solved by then.

Source: Guardian.co.uk

January 23, 2008December 26, 2015 by Nancy Atkinson

Researchers Plan to Launch Paper Airplane from ISS

This is from the “why is anyone spending money on this?” department. Researchers from the University of Tokyo have teamed up with members of the Japan Origami Airplane Association to develop a paper aircraft capable of surviving the flight from the International Space Station to the Earth’s surface. The only problem is that no one knows where the paper airplane might land, and no tracking device is in the works to be used. So, the plan is to do an experiment with no way of gathering any data.

The researchers began testing the strength and heat resistance of an 8 centimeter (3.1 in) long prototype on January 17 in an ultra-high-speed wind tunnel at the University of Tokyo. In the tests, the origami glider — which is shaped like the Space Shuttle and has been treated to withstand intense heat — will be subjected to wind speeds of Mach 7, or about 8,600 kilometers (5,300 miles) per hour.

The researchers claim this paper airplane will come down more slowly than say, a real spacecraft, and it is not expected to burn up on re-entry.

No launch date has been set for the paper spaceplane, but Shinji Suzuki, an aerospace engineering professor at the University of Tokyo, is thinking ahead. “We hope the space station crew will write a message of peace on the plane before they launch it,” says Suzuki. “We don’t know where in the world the plane will land, but it would be nice to send a message to whoever finds it.”

Even if the paper airplane does make it through the atmosphere unscathed, given that our planet is 70% water, don’t hold out much hope for it being found.

Original News Source: Pink Tentacle

January 20, 2008December 26, 2015 by Ian O'Neill

A Possible Answer to Flyby Anomalies

galileo_earth.thumbnail.jpg — Artist's impression of the Galileo mission above Earth - which spent seven years (1995–2003) orbiting Jupiter. Credit: NASA

Strange things are happening to our robotic spaceÂ explorers. Also known as the “Pioneer effect“Â (the unexpected and sudden alterations to Pioneer 10 and Pioneer 11 trajectories measured as they continue their journey into the outer solar system), similar anomalies areÂ being seenÂ in flybys by modern space probes. Earth flybys by Galileo, Rosetta, NEAR and Cassini have all experienced a sudden boost in speed. After cancelling out all possible explanations, including leakage of fuel and velocity measurement error, a new study suggests the answer may lie in a bizarre characteristic of universal physics…

Planetary flybys are an essential aid to interplanetary missions to gain energy as they accelerate on their merry way to their destination. Gravity assists are accurately calculated by mission scientists so the time of arrival can be calculated down to the minute. Considering most missions take years to complete, this degree of accuracy is amazing, but essential.

So, when Galileo completed gravity assist past Earth on December 8, 1990, to speed it toward Jupiter, you can imagine NASA’s surprise to find that Galileo had accelerated suddenly, andÂ for no apparent reason. This small boost was tiny, but through the use of the Deep Space Network, extremely accurate measurements of the speeding craft could be made. Galileo had accelerated 3.9 mm/s.

This isn’t an isolated case. During Earth flybys byÂ the space probes NEAR, Cassini-Huygens and Rosetta,Â all experienced a unexplained boosts of 13 mm/s, 0.11 mm/s and 2 mm/s respectively. Once technical faults, observational errors, radiation pressure, magnetic instabilities and electrical charge build-up could be ruled out, focus is beginning to turn to more exotic explanations.

A recent study by Magic McCulloch suggests that “Unruh radiation” may be the culprit. The Unruh effect, put simply, suggests that accelerating bodies experience a type of electromagnetic radiation. At very low acceleration, the wavelength emitted will be so large that a whole wavelength will be longer than the dimensions of the Universe (otherwise known as the Hubble Distance). Low acceleration would therefore generate waves that have no effect on the body. However, should the accelerating body (i.e. GalileoÂ getting accelerated by Earth’s gravity during the 1990 flyby) slowly exceed an acceleration threshold, the Unruh radiation will decrease in wavelength (smaller thanÂ the Hubble Distance), causing a tiny, but measurable “boost” to its increasing velocity.

Although complex, this theory is very interesting and proves that althoughÂ weÂ can calculate the arrival time of space probes down to the nearest minute, the Universe will continue to throw up some perplexing issues for a long time yet.

Sources: arXiv Blog, arXiv abstract and paper download

January 18, 2008December 26, 2015 by Ian O'Neill

Most Advanced Ion Engines For 2013 BepiColombo Mission to Mercury

British scientists have been given the green light to begin the development of the most advanced ion engines ever to be used in space travel history. Set for launch in 2013, the European/Japanese BepiColombo mission to Mercury will be propelled to the Solar System’s innermost planet by advanced ion engines, with an efficiency equivalent to 17.8 million miles per gallon. This is one very cheap spaceship to fly!

We are currently being dazzled and amazed at the sheer detail of the images being transmitted by NASA’s MESSENGER mission flyby of the tiny planet Mercury. While we watch and wait for MESSENGER to eventually establish an orbit (insertion should occur in the spring of 2011), UK scientists, working with the ESA and Astrium (Europe’s largest space contractor), are hard at work designing the engines for the next big mission to the inner Solar System: BepiColombo. The mission consists of two orbiters: the Mercury Planetary Orbiter (MPO), to carry out mapping tasks over the planet, and the Mercury Magnetospheric Orbiter (MMO), to characterize the planets mysterious magnetosphere. The two craft will travel as one for the 6 year journey to Mercury, but separate at orbital insertion.

Although BepiColombo will use the gravitational pull of the Moon, Earth, Venus and then Mercury to actually get it to its destination, a large amount of energy is required to slow the craft down, countering the Sun’s gravity. Without an engine to thrust against BepiColombo‘s decent into the huge gravitational pull of the Sun, the mission would be doomed to overshoot Mercury and fall to a fiery end. This is where the ion engines come in.

Ion engines have been used in space missions before (such as the SMART-1 mission to the Moon in 2003), but the new generation engines currently undergoing development for the next Mercury mission will be far more efficient while providing sufficient thrust. Better efficiency means less fuel. Less fuel means less mass and volume, saving on launch cost and allowing more room for scientific instrumentation.

Ion engines work by channeling electrically charged particles (ions) through an electric field. Doing this accelerates the ions to high velocities. Each particle has a mass (albeit tiny), so each particle also carries a momentum when fired from the engine. Shoot enough particles out of the engine and you produce a thrust the spacecraft can use to accelerate or (in the case of BepiColombo) slow down. Ion engines do have a drawback. Although they are fuel efficient, the thrust can be small, so missions can take longer to complete; time must be allowed for the long-term thrust to have an effect on the velocity of the spacecraft. However, this shortfall for ion propulsion won’t deter space scientists from using this new technology, as the pros definitely outweigh the cons.

So, we can nowÂ look forward toÂ over a decadeÂ of exploration of MercuryÂ by MESSENGER and BepiColombo, one of the most uncharted and mysterious planets to orbit the Sun.

Source: Telegraph.co.uk