Don’t Breathe the Moon Dust

This is a true story.

In 1972, Apollo astronaut Harrison Schmidt sniffed the air in his Lunar Module, the Challenger. “[It] smells like gunpowder in here,” he said. His commander Gene Cernan agreed. “Oh, it does, doesn’t it?”

The two astronauts had just returned from a long moonwalk around the Taurus-Littrow valley, near the Sea of Serenity. Dusty footprints marked their entry into the spaceship. That dust became airborne–and smelly.

Later, Schmidt felt congested and complained of “lunar dust hay fever.” His symptoms went away the next day; no harm done. He soon returned to Earth and the anecdote faded into history.

But Russell Kerschmann never forgot. He’s a pathologist at the NASA Ames Research Center studying the effects of mineral dust on human health. NASA is now planning to send people back to the Moon and on to Mars. Both are dusty worlds, extremely dusty. Inhaling that dust, says Kerschmann, could be bad for astronauts.

“The real problem is the lungs,” he explains. “In some ways, lunar dust resembles the silica dust on Earth that causes silicosis, a serious disease.” Silicosis, which used to be called “stone-grinder’s disease,” first came to widespread public attention during the Great Depression when hundreds of miners drilling the Hawk’s Nest Tunnel through Gauley Mountain in West Virginia died within half a decade of breathing fine quartz dust kicked into the air by dry drilling–even though they had been exposed for only a few months. “It was one of the biggest occupational-health disasters in U.S. history,” Kerschmann says.

This won’t necessarily happen to astronauts, he assures, but it’s a problem we need to be aware of–and to guard against.

Quartz, the main cause of silicosis, is not chemically poisonous: “You could eat it and not get sick,” he continues. “But when quartz is freshly ground into dust particles smaller than 10 microns (for comparison, a human hair is 50+ microns wide) and breathed into the lungs, they can embed themselves deeply into the tiny alveolar sacs and ducts where oxygen and carbon dioxide gases are exchanged.” There, the lungs cannot clear out the dust by mucous or coughing. Moreover, the immune system’s white blood cells commit suicide when they try to engulf the sharp-edged particles to carry them away in the bloodstream. In the acute form of silicosis, the lungs can fill with proteins from the blood, “and it’s as if the victim slowly suffocates” from a pneumonia-like condition.

Lunar dust, being a compound of silicon as is quartz, is (to our current knowledge) also not poisonous. But like the quartz dust in the Hawk’s Nest Tunnel, it is extremely fine and abrasive, almost like powdered glass. Astronauts on several Apollo missions found that it clung to everything and was almost impossible to remove; once tracked inside the Lunar Module, some of it easily became airborne, irritating lungs and eyes.

Martian dust could be even worse. It’s not only a mechanical irritant but also perhaps a chemical poison. Mars is red because its surface is largely composed of iron oxide (rust) and oxides of other minerals. Some scientists suspect that the dusty soil on Mars may be such a strong oxidizer that it burns any organic compound such as plastics, rubber or human skin as viciously as undiluted lye or laundry bleach.

“If you get Martian soil on your skin, it will leave burn marks,” believes University of Colorado engineering professor Stein Sture, who studies granular materials like Moon- and Mars-dirt for NASA. Because no soil samples have ever been returned from Mars, “we don’t know for sure how strong it is, but it could be pretty vicious.”

Moreover, according to data from the Pathfinder mission, Martian dust may also contain trace amounts of toxic metals, including arsenic and hexavalent chromium–a carcinogenic toxic waste featured in the docudrama movie Erin Brockovich (Universal Studios, 2000). That was a surprising finding of a 2002 National Research Council report called Safe on Mars: Precursor Measurements Necessary to Support Human Operations on the Martian Surface.

The dust challenge would be especially acute during windstorms that occasionally envelop Mars from poles to equator. Dust whips through the air, scouring every exposed surface and sifting into every crevice. There’s no place to hide.

To find ways of mitigating these hazards, NASA is soon to begin funding Project Dust, a four-year study headed by Masami Nakagawa, associate professor in the mining engineering department of the Colorado School of Mines. Project Dust will study such technologies as thin-film coatings that repel dust from tools and other surfaces, and electrostatic techniques for shaking or otherwise removing dust from spacesuits.

These technologies, so crucial on the Moon and Mars, might help on Earth, too, by protecting people from sharp-edged or toxic dust on our own planet. Examples include alkaline dust blown from dry lakes in North American deserts, wood dust from sawmills and logging operations, and, of course, abrasive quartz dust in mines.

The road to the stars is surprisingly dusty. But, says Kerschmann, “I strongly believe it’s a problem that can be controlled.”

Original Source: [email protected] Story

Is There Water on the Moon?

The first object in the night sky most of us ever saw, the Moon remains a mystery. Haunted by poets, looked upon by youngsters in love, studied intensely by astronomers for four centuries, examined by geologists for the last 50 years, walked upon by twelve humans, this is Earth’s satellite.

And as we look towards the Moon with thoughts of setting up a permanent home there, one new question is paramount: does the Moon have water? Although none has been definitely detected, recent evidence suggests that it’s there.

Why should there be water on the Moon? Simply for the same reason that there’s water on Earth. A favorite theory is that water, either as water by itself or as its components of hydrogen and oxygen, was deposited on Earth during its early history–mostly during a period of “late heavy bombardment” 3.9 billion years ago–by the impacts of comets and asteroids. Because the Moon shares the same area of space as Earth, it should have received its share of water as well. However, since it has only a tiny fraction of Earth’s gravity, most of the Moon’s water supply should have evaporated and drifted off into space long ago. Most, but perhaps not all.

In ancient times, observers commonly thought the Moon had abundant water–in fact, the great lava plains like Mare Imbrium were called maria, or seas. But when Neil Armstrong and Buzz Aldrin landed on the Moon in 1969, they stepped out not into the water of the Sea of Tranquillity, but onto basaltic rock. No one was surprised by that–the idea of lunar maria had been replaced by lava plains decades earlier.

As preparations were underway in the mid 1960s for the Apollo program, questions about water on the Moon were barely on the radar screen. Geologists and astronomers were divided at the time as to whether the lunar surface was a result of volcanic forces from beneath, or cosmic forces from above. Grove Carl Gilbert in 1893 already had the answer. That famous geologist suggested that large asteroidal objects hit the Moon, forming its craters. Ralph Baldwin articulated the same idea in 1949, and Gene Shoemaker revived the idea again around 1960. Shoemaker, almost alone among geologists of his day, saw the Moon as a fertile subject for field geology. He saw the craters on the Moon as logical impact sites that were formed not gradually in eons, but explosively in seconds.

The Apollo flights confirmed that the dominant geological process on the Moon is impact-related. That discovery, in turn, ushered in a new question: Since Earth’s water was probably delivered largely by comets and asteroids, could this process have done the same for the Moon? And could some of that water still be there?

In 1994, the SDI-NASA Clementine spacecraft orbited the Moon and mapped its surface. In one experiment, Clementine beamed radio signals into shadowed craters near the Moon’s south pole. The reflections, received by antennas on Earth, seemed to come from icy material.

That makes sense. If there is water on the Moon, it’s probably hiding in the permanent shadows of deep, cold craters, safe from vaporizing sunlight, frozen solid.

So far so good, but… the Clementine data were not conclusive, and when astronomers tried to find ice in the same craters using the giant Arecibo radar in Puerto Rico, they couldn’t. Maybe Clementine was somehow wrong.

In 1998, NASA sent another spacecraft, Lunar Prospector, to check. Using a device called a neutron spectrometer, Lunar Prospector scanned the Moon’s surface for hydrogen-rich minerals. Once again, polar craters yielded an intriguing signal: neutron ratios indicated hydrogen. Could it be the “H” in H2O? Many researchers think so.

Lunar Prospector eventually sacrificed itself to the search. When the spacecraft’s primary mission was finished, NASA decided to crash Prospector near the Moon’s south pole, hoping to liberate a bit of its meager layer of water. Earth’s satellite might briefly become a comet as amounts of water vapor were released.

Lunar Prospector crashed, as planned, and several teams of researchers tried to detect that cloud, but without success. Either there was no water, or there was not enough water to be detected by Earth-based telescopes, or the telescopes were not looking in precisely the right place. In any event, no water was found from Prospector’s impact.

In 2008, NASA plans to send a new spacecraft to the Moon: the Lunar Reconnaissance Orbiter (LRO), bristling with advanced sensors that can sense water in at least four different ways. Scientists are hopeful that LRO can decide the question of Moon water once and for all.

Our interest is not just scientific. If we are indeed to build a base on the Moon, the presence of water already there would offer a tremendous advantage in building and running it. It’s been 35 years since we first set foot on the Moon. Now ambitious eyes once again look toward our satellite not just as a place to visit, but as a place to live.

Original Source: [email protected]

The Search for the Mountain of Eternal Sunlight

ESA?s SMART-1 mission to the Moon has been monitoring the illumination of lunar poles since the beginning of 2005, about two months before arriving at its final science orbit.

Ever since, the AMIE on-board camera has been taking images which are even able to show polar areas in low illumination conditions. Images like these will help identify if peaks of eternal light exist at the poles.

SMART-1 took views of the North Polar Region from a distance of 5000 km during a pause in the spiralling descent to the science orbit. One can see highland terrains, very highly cratered due to their old age. The rims of the large craters project very long shadows even on surrounding features. SMART-1 is monitoring the polar shadows cast during the Moon rotation, and their seasonal variations, to look for places with long-lasting illumination.

The image shows a 275 km area close to the North pole (upper left corner) observed by SMART-1 on 29 December 2004 from a distance of 5500 km. This shows a heavily cratered highland terrain, and is used to monitor illumination of polar areas, and long shadows cast by large crater rims.

SMART-1 also observated a North polar area 250 km wide on 19 January 2005 (close to North winter solstice) from a distance of 5000 km. The illuminated part of crater rim is very close to the North pole and is a candidate for a peak of eternal sunlight.

?This shows the ability of SMART-1 and its camera to image even for low light levels at the poles and prospect for sites for future exploration?, says AMIE camera Principal Investigator Jean-Luc Josset, (SPACE-X, Switzerland).

?If we can confirm peaks of eternal light?, adds Bernard Foing, SMART-1 Project Scientist, ?these could be a key locations for possible future lunar outposts?.

The existence of peaks of eternal light at the poles, that is areas that remain eternally illuminated regardless of seasonal variations, was first predicted in the second half of the nineteenth century by the astronomer Camille Flammarion. Even if for most of the Moon the length of the day does not vary perceptibly during the course of seasons, this is not the case over the poles, where illumination can vary extensively during the course of the year. The less favourable illumination conditions occur around the northern winter solstice, around 24 January. There are areas at the bottom of near-polar craters that do not see direct sunshine, where ice might potentially be trapped. Also there are areas at higher elevation on the rim of polar craters that see the Sun more than half of the time. Eventually, there may be areas that are always illuminated by sunlight.

Original Source: ESA News Release

Podcasts: Best Spot for a Lunar Base

In case you missed the news, NASA is headed back to the Moon in the next decade. A permanent lunar base could be down the road, so scientists are starting to consider where we should build. Ben Bussey, with Johns Hopkins University Applied Physics Laboratory in Maryland likes the Moon’s North Pole. It’s got everything you might need for a long-term stay: permanent sunlight, relatively stable temperatures, and lots of lunar soil. And as an added bonus, there might be plenty of frozen water hiding in lunar craters.
Continue reading “Podcasts: Best Spot for a Lunar Base”

India and Europe Agree on Lunar Mission

Image credit: ESA
On 17 March the ESA Council, at its meeting in Paris, unanimously approved a cooperation agreement between ESA and the Indian Space Research Organisation for India?s first moon mission ? Chandrayaan-1.

The Indian Space Research Organisation (ISRO), founded in 1969, launched its first satellite in 1975. Since then it has developed a number of launch vehicles as well as satellites for Earth observation, remote sensing, telecommunications and weather forecasting. India has its own launch site at Sriharikota but has also used Europe?s Spaceport in French Guiana to launch its satellites. Chandrayaan-1 marks its first venture into planetary space science.

Under the agreement Europe will coordinate and support the provision of three instruments: CIXS-2, the Chandrayaan-1 Imaging X-Ray Spectrometer; SARA, a Sub-keV Atom Relecting Analyzer; and SIR-2, a Near-Infrared Spectrometer. It will also support the hardware for the High-Energy X-ray Spectrometer (HEX). Direct ESA in-kind contributions are also foreseen under this historical agreement. In return, all data resulting from the instruments will be made immediately available to ESA Member States through ESA.

The instruments requested are identical to those on ESA?s SMART-1. Launched in 2003, SMART-1, having demonstrated a new solar electric propulsion motor and tested other technologies on its way to the moon, has just started its science phase. It will make the first comprehensive inventory of key chemical elements in the lunar surface.

ISRO plans to send a 1050 kg (523 kg initial orbit mass and 440 kg dry mass) remote sensing satellite to help unravel mysteries about the origin and evolution of the solar system in general and the Moon in particular. The satellite, which is expected to have an operational life of two years, will be launched by India?s Polar Satellite Launch Vehicle in 2007/2008.

ESA will give ISRO the benefit of its experience with SMART-1 and will further assist in operations facilitation as well as providing the science instruments.

ESA’s SMART-1 put Europe in the lead in the new race back to the Moon. As well as India and Japan, China and the USA also intend to launch lunar missions in the coming years. The cooperation with India will keep European scientists in the forefront.

The ESA Director of Science, David Southwood, said: “One should also see the cooperation in a wider context. Space science is a natural area for space agencies to learn to work together in technical matters. Such cooperation remains a strategic element in the Director General’s wider agenda for the Agency.”

Original Source: ESA News Release

SMART-1’s Mission Extended

Illustration credit: ESA
ESA’s SMART-1 mission was extended by one year, pushing back the mission end date from August 2005 to August 2006.

ESA’s Science Programme Committee endorsed unanimously the proposed one-year extension of SMART-1 on 10 February 2005.

The extension by one year of the mission will provide opportunities to extend the global coverage, compared to the original six-month mission, and to map both southern and northern hemispheres at high resolution. The new orbit will also be more stable and require less fuel for maintenance.

The extension also gives the possibility to perform detailed studies of areas of interest by performing stereo measurements for deriving topography, multi-angle observations for studying the surface ‘regolith’ texture, and mapping potential landing sites for future missions.

Implementation of this mission extension will be in two periods of six months that correspond to different orbital parameters and illumination conditions. During the first period, the southern survey study is to be completed and dedicated pointings made for multi-angle, stereo and polar illumination studies.

In the second period, high-resolution coverage of the Moon on the equator and part of the northern hemisphere will take place due to the favourable illumination conditions. High resolution follow-up observations of specific targets will also be made, as well as observations relevant for the preparation of future international lunar exploration missions.

Between 10 January and 9 February, SMART-1’s electric propulsion system (or ‘ion engine’) was not active. This allowed mission controllers to accurately determine the amount of fuel remaining, as well as ensure accurate planning for a mission extension, and obtain reconnaissance data from an orbit at 1000-4500 kilometres above the lunar surface.

All the instruments have been performing well from this orbit. As the ion engine is now active again, SMART-1 will spiral down to arrive at the lunar science orbit by the end of February.

The cruise and lunar approach has permitted the demonstration of a number of technologies, such as spacecraft, navigation, operations and instruments, which will be useful for future missions. The SMART-1 mission has now fulfilled its primary objective ? to demonstrate the viability of solar electric propulsion, or ‘ion drives’.

Original Source: ESA News Release

SMART-1’s First Image of the Moon

Image credit: ESA
ESA’s SMART-1 captured its first close-range images of the Moon this January, during a sequence of test lunar observations from an altitude between 1000 and 5000 kilometres above the lunar surface.

SMART-1 entered its first orbit around the Moon on 15 November 2004. It has spent the two months following spiralling down to the Moon and testing its array of instruments.

The first four days after being captured by the lunar gravity were very critical. There had been the risk, being in an ‘unstable’ trajectory, of escaping the Moon’s orbit or crashing onto the surface. Because of this, the electric propulsion system (or ‘ion engine’) started a thrust to stabilise the capture.

The ion engine was switched on until 29 December, allowing SMART-1 to make ever-decreasing loops around the Moon. The engine was switched off between 29 December and 3 January 2005 to allow scientists to start observations. At this point, the AMIE camera took the close-up lunar images. The engine was switched off again to optimise fuel consumption on 12 January, and SMART-1 will spend until 9 February making a medium resolution survey of the Moon, taking advantage of the favourable illumination conditions.

ESA’s SMART-1 Project Scientist Bernard Foing said “A sequence of test lunar observations was done in January at distances between 1000 and 5000 kilometres altitude, when the electric propulsion was paused. We are conducting more survey test observations until the electric propulsion resumes from 9 February to spiral down further towards the Moon. SMART-1 will arrive on 28 February at the initial orbit with altitudes between 300 and 3000 kilometres to perform the first phase of nominal science observations for five months.”

The first close-up image shows an area at lunar latitude 75? North with impact craters of different sizes. The largest crater shown here, in the middle left of the image, is Brianchon. The second largest, at the bottom of the image, is called Pascal.

At low illumination angles, the crater shadows allow scientists to derive the height of crater rims.

“This image was the first proof that the AMIE camera is still working well in lunar orbit,” says AMIE Principal Investigator Jean-Luc Josset of Space-X.

The composite images shown here were created to show larger-scale features. The first mosaic shows the complex impact crater Pythagoras and the strip of images (bottom) was produced from images taken consecutively along one orbit.

Starting with this mosaic, SMART-1 scientists expect to build up a global medium-resolution context map, where high-resolution images later observed from lower altitude can be integrated.

Original Source: ESA News Release

Experiments Chosen For Lunar Orbiter

NASA has selected six proposals to provide instrumentation and associated exploration/science measurement investigations for the Lunar Reconnaissance Orbiter (LRO), the first spacecraft to be built as part of the Vision for Space Exploration.

The LRO mission is scheduled to launch in the fall of 2008 as part of NASA’s Robotic Lunar Exploration Program. The mission will deliver a powerful orbiter to the vicinity of the moon to obtain measurements necessary to characterize future robotic and human landing sites. It also will identify potential lunar resources and document aspects of the lunar radiation environment relevant to human biological responses.

Proposals were submitted to NASA in response to an Announcement of Opportunity released in June 2004. Instrumentation provided by these selected measurement investigations will be the payload of the mission scheduled to launch in October 2008.

“The payload we have selected for LRO builds on our collective experience in remote sensing of the Earth and Mars,” said NASA’s Deputy Associate Administrator for the Science Mission Directorate, Dr. Ghassem Asrar. “The measurements obtained by these instruments will characterize in unprecedented ways the moon’s surface and environment for return of humans in the next decade,” he added.

“LRO will deliver measurements that will be critical to the key decisions we must make before the end of this decade,” said NASA’s Associate Administrator for the Exploration Systems Mission Directorate, Craig Steidle. “We are extremely excited by this innovative payload, and we are confident it will fulfill our expectations and support the Vision for Space Exploration,” Steidle added.

“The instruments selected for LRO represent an ideal example of a dual use payload in which exploration relevance and potential scientific impact are jointly maximized,” NASA’s Chief Scientist, Dr. Jim Garvin said. “I am confident LRO will discover a ‘new moon’ for us, and in doing so shape our human exploration agenda for our nearest planetary neighbor for decades to come,” he said.

The selected proposals will conduct Phase A/B studies to focus on how proposed hardware can best be accommodated, completed, and delivered on a schedule consistent with the mission timeline. An Instrument Preliminary Design Review and Confirmation for Phase C Review will be held at the completion of Phase B.

Selected investigations and principal investigators:

“Lunar Orbiter Laser Altimeter (LOLA) Measurement Investigation” – principal investigator Dr. David E. Smith, NASA Goddard Space Flight Center (GSFC), Greenbelt, Md. LOLA will determine the global topography of the lunar surface at high resolution, measure landing site slopes and search for polar ices in shadowed regions.

“Lunar Reconnaissance Orbiter Camera” (LROC) – principal investigator Dr. Mark Robinson, Northwestern University, Evanston, Ill. LROC will acquire targeted images of the lunar surface capable of resolving small-scale features that could be landing site hazards, as well as wide-angle images at multiple wavelengths of the lunar poles to document changing illumination conditions and potential resources.

“Lunar Exploration Neutron Detector” (LEND) – principal investigator Dr. Igor Mitrofanov, Institute for Space Research, and Federal Space Agency, Moscow. LEND will map the flux of neutrons from the lunar surface to search for evidence of water ice and provide measurements of the space radiation environment which can be useful for future human exploration.

“Diviner Lunar Radiometer Experiment” – principal investigator Prof. David Paige, UCLA, Los Angeles. Diviner will map the temperature of the entire lunar surface at 300 meter horizontal scales to identify cold-traps and potential ice deposits.

“Lyman-Alpha Mapping Project” (LAMP) – principal investigator Dr. Alan Stern, Southwest Research Institute, Boulder, Colo. LAMP will observe the entire lunar surface in the far ultraviolet. LAMP will search for surface ices and frosts in the polar regions and provide images of permanently shadowed regions illuminated only by starlight.

“Cosmic Ray Telescope for the Effects of Radiation” (CRaTER) – principal investigator Prof. Harlan Spence, Boston University, Mass. CRaTER will investigate the effect of galactic cosmic rays on tissue-equivalent plastics as a constraint on models of biological response to background space radiation.

The LRO project is managed by GSFC. Goddard will acquire the launch system and spacecraft, provide payload accommodations, mission systems engineering, assurance, and management. For information about NASA and agency programs on the Internet, visit:

http://www.nasa.gov

Original Source: NASA News Release

SMART-1 Goes Into Lunar Orbit

Image credit: ESA
ESA?s SMART-1 is successfully making its first orbit of the Moon, a significant milestone for the first of Europe’s Small Missions for Advanced Research in Technology (SMART) spacecraft.

A complex package of tests on new technologies was successfully performed during the cruise to the Moon, while the spacecraft was getting ready for the scientific investigations which will come next. These technologies pave the way for future planetary missions.

SMART-1 reached its closest point to the lunar surface so far – its first ?perilune? ? at an altitude of about 5000 kilometres at 18:48 Central European Time (CET) on 15 November.

Just hours before that, at 06:24 CET, SMART-1?s solar-electric propulsion system (or ?ion engine?) was started up and is now being fired for the delicate manoeuvre that will stabilise the spacecraft in lunar orbit.

During this crucial phase, the engine will run almost continuously for the next four days, and then for a series of shorter burns, allowing SMART-1 to reach its final operational orbit by making ever-decreasing loops around the Moon. By about mid-January, SMART-1 will be orbiting the Moon at altitudes between 300 kilometres (over the lunar south pole) and 3000 kilometres (over the lunar north pole), beginning its scientific observations.

The main purpose of the first part of the SMART-1 mission, concluding with the arrival at the Moon, was to demonstrate new spacecraft technologies. In particular, the solar-electric propulsion system was tested over a long spiralling trip to the Moon of more than 84 million kilometres. This is a distance comparable to an interplanetary cruise.

For the first time ever, gravity-assist manoeuvres, which use the gravitational pull of the approaching Moon, were performed by an electrically propelled spacecraft. The success of this test is important to the prospects for future interplanetary missions using ion engines.

SMART-1 has demonstrated new techniques for eventually achieving autonomous spacecraft navigation. The OBAN experiment tested navigation software on ground computers to determine the exact position and velocity of the spacecraft using images of celestial objects taken by the AMIE camera on SMART-1 as references. Once used on board future spacecraft, the technique demonstrated by OBAN will allow spacecraft to know where they are in space and how fast they are moving, limiting the need for intervention by ground control teams.

SMART-1 also carried out deep-space communication tests, with the KaTE and RSIS experiments, consisting of testing radio transmissions at very high frequencies compared to traditional radio frequencies. Such transmissions will allow the transfer of ever-increasing volumes of scientific data from future spacecraft. With the Laser Link experiment, SMART-1 tested the feasibility of pointing a laser beam from Earth at a spacecraft moving at deep-space distances for future communication purposes.

During the cruise, to prepare for the lunar science phase, SMART-1 made preliminary tests on four miniaturised instruments, which are being used for the first time in space: the AMIE camera, which has already imaged Earth, the Moon and two total lunar eclipses from space, the D-CIXS and XSM X-ray instruments, and the SIR infrared spectrometer.

In all, SMART-1 clocked up 332 orbits around Earth. It fired its engine 289 times during the cruise phase, operating for a total of about 3700 hours. Only 59 kilograms of xenon propellant were used (out of 82 kilograms). Overall, the engine performed extremely well, enabling the spacecraft to reach the Moon two months earlier than expected.

The extra fuel available also allowed the mission designers to significantly reduce the altitude of the final orbit around the Moon. This closer approach to the surface will be even more favourable for the science observations that start in January. The extra fuel will also be used to boost the spacecraft back into a stable orbit, after six months of operations around the Moon, in June, if the scientific mission is extended.

Original Source: ESA News Release

SMART-1 Nearly Captured By the Moon

Image credit: ESA
From 10 to 14 October the ion engine of ESA?s SMART-1 carried out a continuous thrust manoeuvre in a last major push that will get the spacecraft to the Moon capture point on 13 November.

SMART-1, on its way to the Moon, has now covered more than 80 million kilometres. Its journey started on 27 September 2003, when the spacecraft was launched on board an Ariane 5 rocket from Europe?s spaceport in Kourou, French Guiana. Since then, it has been spiralling in progressively larger orbits around Earth, to eventually be captured by the lunar gravity and enter into orbit around the Moon in November this year.

The SMART-1 mission was designed to pursue two main objectives. The first is purely technological: to demonstrate and test a number of space techniques to be applied to future interplanetary exploration missions. The second goal is scientific, mainly dedicated to lunar science. It is the technology demonstration goal, in particular the first European flight test of a solar-powered ion engine as a spacecraft?s main propulsion system, that gave shape to the peculiar route and duration (13 months) of the SMART-1 journey to the Moon.

The long spiralling orbit around Earth, which is bringing the spacecraft closer and closer to the Moon, is needed for the ion engine to function and be tested over a distance comparable to that a spacecraft would travel during a possible interplanetary trip. The SMART-1 mission is also testing the response of a spacecraft propelled by such an engine during gravity-assisted manoeuvres. These are techniques currently used on interplanetary journeys, which make use of the gravitational pull of celestial objects (e.g. planets) for the spacecraft to gain acceleration and reach its final target while saving fuel.

In SMART-1?s case, the Moon?s gravitational pull has been exploited in three ‘lunar resonance’ manoeuvres. The first two successfully took place in August and September 2004. The last resonance manoeuvre was on 12 October, during the last major ion engine thrust, which lasted nearly five days, from 10 to 14 October. Thanks to this final thrust, SMART-1 will make two more orbits around Earth without any further need to switch on the engine, apart from minor trajectory correction if needed. The same thrust will allow the spacecraft to progressively fall into the natural sphere of attraction of the Moon and start orbiting around it from 13 November, when it is 60 000 kilometres from the lunar surface.

SMART-1 will reach its first perilune (initial closest distance from the lunar surface) on 15 November, while the ion engine is performing its first and major thrust in orbit around the Moon. After that it will continue orbiting around the Moon in smaller loops until it reaches its final operational orbit (spanning between 3000 and 300 kilometres over the Moon?s poles) in mid-January 2005. From then, for six months Smart-1 will start the first comprehensive survey of key chemical elements on the lunar surface and will investigate the theory of how the Moon was formed.

Original Source: ESA News Release