Category: Missions

Image credit: ESA

The European Space Agency’s SMART-1 spacecraft has been orbiting the Earth for a full month now, and has made 64 complete orbits. Engineers have been wary this week about firing its ion engine with the increased solar activity. There have been a few problems: the engine unexpectedly turned off, but worked fine on the next firing; its star tracker had difficulty orienting the spacecraft but upgrades to the software resolved that. It’s still on track to reach the Moon by March 2005.

The spacecraft is now in its 64th orbit and has been flying in space for one month! The main activity of the last week was to continue the thrust firings of the electric propulsion engine in order to boost the spacecraft orbit. This operation was limited due to problems with the local radiation environment as a result of the recent, high intensity solar activity. The engine has now generated thrust for a total cumulated time of about 300 hours.

Despite the rather short thrusting phase, the electric propulsion engine performance has been periodically monitored as usual by means of the telemetry data transmitted by the spacecraft and by radio-tracking by the ground stations. We noticed that the EP performance is still improving. From the original expected underperformance of about 3%, we went to last week?s slight over-performance of about 0.5% and we now have an engine that gives about 1% higher thrust than expected. This confirms our confidence in the excellent conditions of the electric propulsion system.

In this period we have also experienced an autonomous shut-down, or flame-out, of the engine. This happened on 26 October 2003 at 19:23 UTC, a few hours before a scheduled switch-off. The engine then re-ignited autonomously at the next scheduled thrusting restart without problems. The experts are investigating the problems. One curious coincidence is that at exactly the same time the radiation monitors on two ESA scientific spacecraft in highly elliptical orbits (XMM and Integral) had detected considerable radiation coming probably from a solar flare. This event was so large and potentially dangerous that one instrument on board Integral stopped operations and switched itself in to safe mode.

The electric power provided by the solar arrays has been according to predictions – about 1850 W for this phase of the mission. The power degradation, due to the radiation environment, was also less than expected at 1-1.5 Watts per day. Recently however, starting from October 20, we noticed a sharper degradation of the power, probably due to the increased radiation environment.

The communication, data handling and on-board software subsystems have been performing according to expectations so far. We are also detecting signs of an increase in the local radiation environment. An onboard counter records the number of hits produced by charged particles, like protons or ions, which cause a single bit in the digital circuits of the computer memory to change state, known as a Single Event Upset. We noticed a sharp increase in the count rate from 23 October onwards. This is currently attributed to the increased solar activity.

The thermal subsystem continues to perform well and all the temperatures are as expected. During the last period the spacecraft systems coped very well with a partial lunar eclipse, where the Moon obscured about 70% of the solar disk for around 80 minutes. Although the average spacecraft equipment temperature has not changed much during the mission, some equipment is experiencing temperature fluctuations due to changes in both the spacecraft’s attitude along its orbit and the Sun’s position. The angle between the Sun direction and the orbit line of apses (the line joining the perigee and the apogee) has changed considerably during the mission. It has varied from about 16 degrees at the beginning of the mission to a current value of 35 degrees. This change could be responsible for the increase of the star tracker optical head temperature during part of the orbit. As the Sun gets further away from the line of apses, this effect should be attenuated and the star tracker conditions should improve.

The attitude control subsystem continues to work, in general, very well. The main area of concern in this period has been the star tracker. This advanced autonomous star mapper has failed in the last two weeks to provide good attitude information in a few cases during different parts of the orbit. We have now found the explanation for all cases. It is due to a combination of several effects. The dominant effect is the increased background radiation level, especially protons to which the star tracker CCD is sensitive. This effect, combined with the temperature increase of the star tracker optical head in some parts of the orbit, created ‘hot spots’ in the CCD which were mistakenly interpreted as stars. This problem has been corrected by a software change uploaded to the star tracker computer.

Another problem was caused by the high star richness of some areas of the galaxy where the star tracker is pointing during part of the orbit. Too many stars require a computer processing time in excess of the allocated slot and cause ‘drops’ of attitude determination. The third problem was the blinding that the Earth disk produces to the optical head. These problems have been corrected by modifications to the software of the star tracker, which has been successfully updated onboard. Since these corrections have been made, the star tracker has been working very well and no further drops in attitude determination have been observed.

Original Source: ESA News Release

Image credit: ESA

The European Space Agency’s SMART-1 spacecraft has completed its 50th orbit of the Earth; operating its ion engine for more than 560 hours. The engine can only fire for half of the orbit because the spacecraft needs to raise its orbit until it reaches the Moon. ESA controllers have performed a series of tests on the spacecraft, and almost everything seems to be working perfectly – there’s a minor problem with its star-tracker. The spacecraft is expected to reach the Moon by March 2005, when it will begin mapping surface minerals and ice.

The spacecraft is now completing its 50th orbit and has completed more than 560 hours in space. The main actvity of the last week has been to repeatedly use the electric propulsion engine to gradually alter the spacecraft’s orbit. This is limited to around 15 hours a day based on whether the spacecraft is in eclipse. So far the engine has generated thrust for an accumulated time of about 240 hours.

The electric propulsion engine performance has been periodically monitored by means of telemetry data transmitted by the spacecraft and by radio-tracking at the ground stations. The EP performance has been constantly improving, as expected, during the thrusting phase. During the first firing we measured an underperformance of about 3%, as expected in the early operations of the engine in its first use. Today we have a slight over-performance of about 0.5% which gives us confidence in the excellent conditions of the electric propulsion system.

The electric power provided by the solar arrays is nominal. The expected degradation due to the radiation environment is less severe then the worst case scenario. We can, therefore, assume that we shall be able to thrust at full power for quite some time.

The thermal subsystem is performing very well: all the temperatures are as expected and the heater power consumption is lower than estimated. This is a comfortable situation and gives us confidence that the system will be able to cope well with the long eclipse seasons in the spring of next year.

The communication, data handling and on-board software subsystems have been performing nominally so far. The attitude control subsystem has, in general, been working very well and the controller performance during the thrusting phase has been so smooth and accurate that there has been no need to use the hydrazine thrusters to desaturate the small reaction wheels used as main actuators.

The main area of concern is the star tracker performance. This advanced autonomous star mapper has recently failed to provide good attitude information in a few cases around perigee and eclipse periods. Although the attitude control system can cope with these occasional problems, the spacecraft planned operations are disturbed by these events. The operation team at ESOC is obliged to reschedule the operations to take into account these events. In the meantime the ESTEC project and industry teams are busy trying to find an explanation to these anomalies. Despite this inconvenience the thrusting periods are maintained. More on the subject will be provided in future reports.

Orbital/Trajectory information
The SMART-1 orbit is continuously modified by the effects of the electric propulsion low thrust. The osculating orbital elements are periodically computed by the ESOC specialists. These elements define the so called ‘osculating orbit’ which would be travelled by the spacecraft if at that instant all perturbations, including EP thrust, would cease. So it is an image of the situation at that moment. In reality the path travelled by the spacecraft is a continuous spiral leading from one orbit to another.

In this diagram the GTO, the osculating orbits at launch and at different times are plotted. The large orbit, marked ‘final’, is the one we expect to achieve at the end of the radiation belt escape in about two months.

From the start, the electric propulsion system has managed to increase the semi-major axis of the orbit by 1555 km, increasing the perigee altitude from the original 656 km to 2035 km and the orbital period by more than one hour, from the initial 10 hours 41 minutes to the present 11 hours 42 minutes.

Original Source: ESA News Release

Image credit: NASA/JPL

The Cassini spacecraft has provided a group of Italian researchers with data that confirms Einstein’s general theory of relativity with 50 times more accuracy than before. They measured the frequency shift of radio waves traveling to and from the spacecraft as they went by the Sun. They measured how much the Sun’s gravity bent the radio signals and increased their travel times. Precise measurements are important because there might be a point at which general relativity stops predicting the interactions of gravity. Cassini is expected to reach Saturn on July 1, 2004.

An experiment by Italian scientists using data from NASA’s Cassini spacecraft, currently en route to Saturn, confirms Einstein’s theory of general relativity with a precision that is 50 times greater than previous measurements.

The findings appear in the Sept. 25 issue of the journal Nature. They are part of a scientific collaboration between NASA and the Italian Space Agency. The experiment took place in the summer of 2002, when the spacecraft and Earth were on opposite sides of the Sun separated by a distance of more than 1 billion kilometers (approximately 621 million miles).

Researchers observed the frequency shift of radio waves to and from the spacecraft as the waves passed near the Sun. They precisely measured the change in the round-trip light time of the radio signal as it traveled close to the Sun. The round-trip light time is the time it takes the signal transmitted from the Deep Space Network station in Goldstone Calif., to the spacecraft on the other side of the Sun and back traveling at the speed of light.

“The scientific significance of these results is the important confirmation of the theory of general relativity and the agreement with Einstein’s formulations to an unprecedented experimental accuracy,” said Sami Asmar, manager of the Radio Science Group, which acquired the data for this experiment at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “The technological significance of the experiment is the ability to overcome the harsh solar environment on radio links.”

The researchers measured how much the Sun’s gravity bent an electromagnetic beam, in this case the radio signal transmitted by the spacecraft and received by the ground stations.

According to the theory of general relativity, a massive object like the Sun causes space-time to curve, and a beam of radio waves (or light) that passes by the Sun has to travel further because of the curvature. The extra distance that the radio waves travel from Cassini past the Sun to the Earth delays their arrival; the amount of the delay provides a sensitive test of the predictions of Einstein’s theory. Although deviations from general relativity are expected in some cosmological models, none were found in this experiment.

Tests of general relativity have important cosmological implications. The question is not whether general relativity is true or false, but at which level of accuracy it ceases to describe gravity in a realistic way.

Past tests of general relativity confirmed Einstein’s prediction to an accuracy of one part per thousand. This accuracy was achieved back in 1979 using the Viking landers on Mars. The Cassini experiment confirmed it to an accuracy of 20 parts per million. The key to this improvement has been the adoption of novel technologies in space telecommunications.

The experiment could not have been conducted to this level of accuracy in the past because of noise on the radio link introduced by the solar corona. With the Cassini experiment, this hindrance was overcome by fitting the spacecraft communication system with multiple links at different frequencies. This new capability on the Cassini spacecraft and on the 34-meter (112 foot) diameter antenna at Goldstone, allowed scientists to remove the effects of the interplanetary and solar plasma from the radio data. In addition, the noise from Earth’s atmosphere was strongly reduced by special equipment installed at the Goldstone complex. These technological breakthroughs developed for the Cassini mission have led to unprecedented accuracies in the velocity measurements with benefits for future scientific experiments as well as deep space navigation.

The experiments are part of a series of radio science experiments planned for the cruise phase of the mission, including the search for low frequency gravitational waves.

Cassini will begin orbiting Saturn on July 1, 2004, and release its piggybacked Huygens probe about six months later for descent through the thick atmosphere of the moon Titan.

Cassini-Huygens is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of Caltech, manages the mission for NASA’s Office of Space Science, Washington, D.C. Authors of the Nature paper, “A New Test of General Relativity With the Cassini Space Mission,” are Dr. Bruno Bertotti of the University of Pavia, Italy; Dr Luciano Iess of the University of Rome “La Sapienza”, Italy; and Dr. Paolo Tortora of the University of Bologna, Italy.

Original Source: NASA/JPL News Release

Image credit: ESA

The European Space Agency’s SMART-1 spacecraft passed an important test on Tuesday when it started up its ion engine – the propulsion system that will take it to the Moon. Engineers at the ESA’s control centre sent the spacecraft the command to test fire its engine for an hour, and they didn’t encounter any problems. SMART-1 will use the ion engine to make bigger and bigger orbits around the Earth until it’s caught by the gravity of the Moon. Then it will use the engine to make smaller orbits around the Moon until it’s close enough to begin gathering science data about the surface.

SMART-1’s revolutionary propulsion system was successfully fired at 12:25 UT on 30 September, 2003, in orbit around the Earth.

Engineers at ESOC, the European Space Agency’s control centre in Darmstadt, Germany, sent a command to begin the firing test, which lasted for one hour. This was similar to a trial performed on Earth before SMART-1 was launched.

Several months ago, the ion engine, or Solar Electric Primary Propulsion (SEPP) system, had been placed in a vacuum chamber on the ground and its functions and operation were measured. Now in space and in a true vacuum, the ion engine actually worked better than in the test on ground and has nudged SMART-1 a little closer to the Moon.

This is the first time that Europe flies an electric primary propulsion in space, and also the first European use of this particular type of ion engine, called a ‘Hall-effect’ thruster.

The SEPP consists of a single ion engine fuelled by xenon gas and powered by solar energy. The ion engine will accelerate SMART-1 very gradually to cause the spacecraft to travel in a series of spiralling orbits – each revolution slightly further away from the Earth – towards the Moon. Once captured by the Moon’s gravity, SMART-1 will move into ever-closer orbits of the Moon.

As part of one of the overall mission objectives to test this new SEPP technology, the data will now be analysed to see how much acceleration was achieved and how smoothly the spacecraft travelled. If the ion engine is performing to expectations, ESA engineers will regularly power up the SEPP to send SMART-1 on its way.

Original Source: ESA News Release

Image credit: Arianespace

Europe’s first mission to the Moon, SMART-1, lifted off successfully on board an Ariane-5 rocket Saturday evening. The rocket launched from the Guiana Space Centre at 2314 GMT (7:14 pm EDT) carrying SMART-1 and two other satellites. The spacecraft has deployed its solar arrays, and is currently undergoing an initial checkout of its systems to make sure that everything’s working properly. Its ion engine will begin accelerating the spacecraft towards the Moon on October 4th, but it’s going to be a long trip – it won’t arrive until March 2005.

SMART-1, Europe’s first science spacecraft designed to orbit the Moon, has completed the first part of its journey by achieving its initial Earth orbit after a flawless launch during the night of 27/28 September.

The European Space Agency’s SMART-1 was one of three payloads on Ariane Flight 162. The generic Ariane-5 lifted off from the Guiana Space Centre, Europe’s spaceport at Kourou, French Guiana, at 2014 hrs local time (2314 hrs GMT) on 27 September (01:14 Central European Summer time on 28 September).

42 minutes after launch, all three satellites had been successfully released into a geostationary transfer orbit (742 x 36 016 km, inclined at 7 degrees to the Equator). While the other two satellites are due to manoeuvre towards geostationary orbit, the 367 kg SMART-1 will begin a much longer journey to a target ten times more distant than the geostationary orbit: the Moon.

“Europe can be proud”, said ESA Director General Jean-Jacques Dordain, after witnessing the launch from ESA’s ESOC space operations centre in Darmstadt, Germany, “we have set course for the Moon again. And this is only the beginning: we are preparing to reach much further”.

The spacecraft has deployed its solar arrays and is currently undergoing initial checkout of its systems under control from ESA/ESOC. This checkout will continue until 4 October and will include with the initial firing of SMART-1’s innovative ion engine.

By ion drive to the Moon
Science and technology go hand in hand in this exciting mission to the Moon. The Earth and Moon have over 4 thousand million years of shared history, so knowing the Moon better will help scientists in Europe and all over the world to better understand our planet and will give them valuable new hints on how to better safeguard it” said ESA Director of Science David Southwood, following the launch from Kourou.

As the first mission in the new series of Small Missions for Advanced Research in Technology, SMART-1 is mainly designed to demonstrate innovative and key technologies for future deep space science missions.

The first technology to be demonstrated on SMART-1 will be Solar Electric Primary Propulsion (SEPP), a highly efficient and lightweight propulsion system that is ideal for long-duration deep space missions in and beyond our solar system. SMART-1’s propulsion system consists in a single ion engine fuelled by 82 kg of xenon gas and pure solar energy. This plasma thruster relies on the “Hall effect” to accelerate xenon ions to speed up to 16,000 km/hour. It is able to deliver 70 mN of thrust with a specific impulse (the ratio between thrust and propellant consumption) 5 to 10 times better than traditional chemical thrusters and for much longer durations (months or even years, compared to the few minutes’ operating times typical of traditional chemical engines).

The ion engine is scheduled to go into action on 30 September. At first, it will fire almost continuously “stopping only when the spacecraft is in the Earth’s shadow” to accelerate the probe (at about 0.2 mm/s2) and raise the altitude of its perigee (the lowest point of its orbit) from 750 to 20 000 km. This manoeuvre will take about 80 days to complete and will place the spacecraft safely above the radiation belts that surround the Earth.

Flight 162 ready for launch
Commissioning will be completed within 2 weeks, after which ESA’s control centre at ESOC will be in contact with the spacecraft for two 8-hour periods every week.

Once at a safe distance from Earth, SMART-1 will fire its thruster for periods of several days to progressively raise its apogee (the maximum altitude of its orbit) to the orbit of the Moon. At 200 000 km from Earth, it will begin receiving significant tugs from the Moon as it passes by. It will then perform three gravity-assist manoeuvres while flying by the Moon in late December 2004, late January and February 2005. Eventually, SMART-1 will be “captured” and enter a near-polar elliptical lunar orbit in March 2005. SMART-1 will then use its thruster to reduce the altitude and eccentricity of this orbit.

During this 18-month transfer phase, the solar-electric primary propulsion’s performance, and its interactions with the spacecraft and its environment, will be closely monitored by the Spacecraft Potential, Electron & Dust Experiment (SPEDE) and the Electric Propulsion Diagnostic Package (EPDP) to detect possible side-effects or interactions with natural electric and magnetic phenomena in nearby space.

A promising technology, Solar Electric Primary Propulsion could be applied to numerous interplanetary missions in the Solar System, reducing the size and cost of propulsion systems while increasing manoeuvring flexibility and the mass available for scientific instrumentation.

In addition to Solar Electric Primary Propulsion, SMART-1 will demonstrate a wide range of new technologies like a Li-Ion modular battery package; new-generation high-data-rate deep space communications in X and Ka bands with the X/Ka-band Telemetry and Telecommand Experiment (KaTE); a computer technique enabling spacecraft to determine their position autonomously in space, which is the first step towards fully autonomous spacecraft navigation.

Digging for the Moon’s remaining secrets
In April 2005 SMART-1 will begin the second phase of its mission, due to last at least six months and dedicated to the study of the Moon from a near polar orbit. For more than 40 years, the Moon has been visited by automated space probes and by nine manned expeditions, six of which landed on its surface. Nevertheless, much remains to be learnt about our closest neighbour, and SMART-1’s payload will conduct observations never performed before in such detail.

The Advanced/Moon Micro-Imaging Experiment (AMIE) miniaturised CCD camera will provide high-resolution and high-sensitivity imagery of the surface, even in poorly lit polar areas. The highly compact SIR infrared spectrometer will map lunar materials and look for water and carbon dioxide ice in permanently shadowed craters. The Demonstration Compact Imaging X-ray Spectrometer (D-CIXS) will provide the first global chemical map of the Moon and the X-ray Solar Monitor (XSM) will perform spectrometric observations of the Sun and provide calibration data to D-CIXS to compensate for solar variability.

The SPEDE experiment used to monitor Solar Electric Primary Propulsion interactions with the environment will also study how the solar wind affects the Moon.

The overall data collected by SMART-1 will provide new inputs for studies of the evolution of the Moon, its chemical composition and its geophysical processes, and also for comparative planetology in general.

Paving the way for future space probes
In addition to valuable lunar science, SMART-1’s payload will be involved in the mission’s technology demonstrations to prepare for future-generation deep space missions.

For instance, the AMIE camera will be used to validate the On-Board Autonomous Navigation (OBAN) algorithm, which correlates data from sensors and star trackers to provide navigational data. It will also participate in a laser communication link experiment with ESA’s optical ground station at the Teide Observatory in Tenerife, Canary Islands, trying to detect an incoming laser beam from the ground.

Using both AMIE and KaTE hardware, the Radio Science Investigation System (RSIS) experiment will demonstrate a new way of gauging the interiors of planets and their moons by detecting the well-known tilting motion of the Moon. This technology can be used later by ESA planetary missions.

SMART-1 was developed for ESA by the Swedish Space Corporation, as prime contractor, with contributions from almost 30 contractors from 11 European countries and the United States. Despite its small size, the spacecraft carries 19 kg of science payload consisting in experiments led by Principal Investigators from Finland, Germany, Italy, Switzerland and the United Kingdom.

Despite its relatively small budget and short development schedule, SMART-1 holds tremendous potential for future missions and is a clear illustration of Europe’s ambitions in the exploration of the solar system, also highlighted by June’s launch of Mars Express, which has now completed over the half on its journey to Mars, and the launch of Rosetta, due in February 2004, to visit comet Churyumov-Gerasimenko.

Original Source: ESA News Release

Image credit: NASA

Boeing has picked Dr. Joe Mills to lead their research into the Jupiter Icy Moons Orbiter program for NASA. This ambitious spacecraft will use a nuclear reactor to power an ion engine – it will be so powerful and efficient that it will be able to put itself into orbit around the various moons of Jupiter. The initial research phase is only a $6 million contract to investigate various technology options for the reactor, ion engine, and power conversion. NASA will choose a primary contractor for the mission in 2004.

Boeing [NYSE: BA] has selected Dr. Joe Mills to lead the company?s effort on the Jupiter Icy Moons Orbiter (JIMO) program, part of a NASA initiative to develop nuclear power and electric propulsion technologies to revolutionize space exploration.

Mills and his team will explore technology options for building the first spacecraft that would use nuclear electric propulsion. Boeing is one of three companies exploring technology options (called a Phase A study contract) for JIMO.

Mills previously headed the International Space Station (ISS) program for Boeing NASA Systems. The company is NASA?s prime contractor for the ISS and is responsible for design, construction, integration and operation of the orbital outpost.

?JIMO, like the International Space Station, is an exciting and groundbreaking mission,? said Mills, Boeing JIMO vice president and program manager. ?I?m looking forward to further challenges as we chart the course of space exploration in the 21st century.?

Mills will be replaced as the Boeing ISS vice president and program manager by John Elbon, who is the Boeing Checkout, Assembly and Payload Processing Services (CAPPS) manager at Kennedy Space Center, Fla.

Mills is an internationally known expert in the nuclear safety field with nearly 40 years experience in the aerospace industry. He received a bachelor of science degree in engineering in 1967, a master of science in nuclear engineering in 1969 and a doctorate in nuclear engineering in 1972, all from the University of California, Los Angeles.

Prior to joining the ISS program, Mills spent 20 years in a variety of project and program management positions with Atomics International, a part of Boeing Rocketdyne Propulsion and Power. From 1987 through 1994, he served as program manager to develop space nuclear power for key military and civilian missions.

Mills devoted his early career to nuclear power systems development. He also specialized in the nuclear safety field of liquid metal fast breeder reactors. He also published numerous papers on nuclear power systems and nuclear power safety.

The JIMO Phase A contract is valued at $6 million, with a $5 million option for further work, and runs through fall 2003. Led in this phase by Boeing Phantom Works, the company?s advanced R&D unit, the JIMO team will study technology options for the reactor, power conversion, electric propulsion and other subsystems of the JIMO spacecraft meant to explore the Jovian moons of Ganymede, Callisto and Europa.

NASA currently plans to select an industry prime contractor in fall 2004 to work with the Jet Propulsion Laboratory (JPL) in Pasadena, Calif., to develop, launch and operate the spacecraft.

Mills is responsible for successful execution of the Phase A trade and concept design study, as well as securing the contract to develop, build and support JPL in operation of the spacecraft. Mills leads the team from the Boeing office in Pasadena, Calif.

Mills reports to Mike Mott, NASA Systems vice president and general manager and Ron Prosser, vice president and general manager for Phantom Works Integrated Defense Advanced Systems.

Original Source: Boeing News Release

Image credit: NASA/JPL

Earth’s closest approach to Mars is past, but it’ll just be another two years until the planets are close together again – time to send more probes. Next up will be NASA’s Mars Reconnaissance Orbiter, which will make a detailed inspection of the Martian surface; imaging objects as small as a coffee table. It will also be able to scan underground layers for evidence of water and ice, and measure the atmosphere above the surface to find vents of water vapour escaping from below the surface. The spacecraft is expected to launch on August 10, 2005.

As Earth pulls away from Mars after last month’s close approach, NASA is developing a spacecraft that will take advantage of the next close encounter in 2005.

That spacecraft, Mars Reconnaissance Orbiter, will make a more comprehensive inspection of our planetary neighbor than any previous mission.

For starters, it will examine landscape details as small as a coffee table with the most powerful telescopic camera ever sent to orbit a foreign planet. Some of its other tools will scan underground layers for water and ice, identify small patches of surface minerals to determine their composition and origins, track changes in atmospheric water and dust, and check global weather every day.

“We’re reaching an important stage in developing the spacecraft,” said James Graf, project manager for Mars Reconnaissance Orbiter at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “The primary structure will be completed next month.” The structure weighs 220 kilograms (484 pounds) and stands 3 meters (10 feet) tall. At launch, after gear and fuel are added, it will support over 2 tons.

Also next month, the mission’s avionics test bed will be assembled for the first time and put to use for testing of flight software.

Workers at Lockheed Martin Space Systems, Denver, have already assembled the spacecraft structure and will later add instruments being built for it at the University of Arizona, Tucson; at Johns Hopkins University Applied Physics Laboratory, Laurel, Md.; at the Italian Space Agency, Rome; at Malin Space Science Systems, San Diego, Calif.; and at JPL.

“In several ways, Mars Reconnaissance Orbiter will advance NASA’s follow-the-water strategy for Mars exploration,” said Dr. Richard Zurek, project scientist for the mission.

Current surveys of Mars’ surface composition have found less evidence of water-related minerals than many scientists anticipated after earlier discoveries of plentiful channels that were apparently carved by water flows in the planet’s past. A spectrometer on the Reconnaissance Orbiter is designed to identify some different types of water-related minerals and to see smaller-scale deposits. “Instead of looking for something as big as the Bonneville Salt Flats, we can look for something on the scale of a Yellowstone hot spring,” Zurek said.

Probing below Mars’ surface with penetrating radar, Reconnaissance Orbiter will check whether the frozen water that NASA’s Mars Odyssey spacecraft detected in the top meter or two (yard or two) of soil extends deeper, perhaps as accessible reservoirs of melted water.

Above the surface, an atmosphere-scanning instrument will monitor changes in water vapor at different altitudes and might even locate plumes where water vapor is entering the atmosphere from underground vents, if that’s happening on Mars.

Mars Reconnaissance Orbiter will stream home its pictures and other information using the widest dish antenna and highest power level ever operated at Mars. “The amount of data flowing back to Earth from Mars will be a giant leap over previous missions. It’s like upgrading from a dial-up modem for your computer to a high-speed DSL connection,” Graf said.

The Mars Reconnaissance Orbiter will lay the groundwork for later Mars surface missions in NASA’s plans: a lander called Phoenix selected last month in a competition for a 2007 launch opportunity, and a highly capable rover called Mars Science Laboratory being developed for a 2009 launch opportunity. The orbiter’s high-resolution instruments will help planners evaluate possible landing sites for these missions both in terms of science potential for further discoveries and in terms of landing risks. The orbiter’s communications capabilities will provide a critical transmission relay for the surface missions.

Advantageous opportunities to launch Mars missions come in a rhythm of about every 26 months, shortly before each time Earth overtakes Mars in the two planets’ concentric tracks around the Sun. NASA’s two Mars Exploration Rovers and the European Space Agency’s Mars Express mission were launched during the three months preceding Earth’s most recent passing of Mars on Aug. 27. The Mars Reconnaissance Orbiter team has its work cut out for it to have the spacecraft ready for launch on Aug. 10, 2005, which is about 10 weeks before the next close approach.

Original Source: NASA/JPL News Release

Image credit: ESA

The European Space Agency’s Smart-1 spacecraft has been mated to the top of its Ariane 5 rocket, and everything is ready to go for its September 27th launch. Smart-1’s primary mission will be to test out new technologies, including solar electric (ion) propulsion and autonomous navigation. Even though it’s launching in just a few days, it will arrive at the Moon in January 2005, where it will begin analyzing the chemical composition of the Moon’s surface. It will also search for evidence of water ice at the Moon’s southern pole.

Europe’s first mission to the Moon will soon be under way, and UK scientists are looking forward to unravelling some of the secrets of our neighbouring world.

SMART-1 – the European Space Agency’s first Small Mission for Advanced Research in Technology -is now expected to lift off from Kourou, French Guiana, just after midnight on Sunday, 28 September.

Although it is primarily intended to demonstrate innovative technologies such as solar-electric (ion) propulsion and autonomous navigation, SMART-1 also carries a number of scientific experiments that will provide new insights into some of the unanswered questions about our nearest celestial neighbour.

On arrival in lunar orbit (expected to be in January 2005), these instruments will search for signs of water ice in permanently shaded craters near the Moon’s poles, provide data on the still uncertain origin of the Moon, and reconstruct its evolution by mapping the surface distribution of minerals and key chemical elements.

The main UK contribution is a compact X-ray spectrometer known as D-CIXS (pronounced dee-kicks), which has been developed by Principal Investigator, Professor Manuel Grande, and his team at CCLRC Rutherford Appleton Laboratory. D-CIXS will help to determine the elements that make up the lunar surface and so provide important information about how the Moon was formed.

“Despite decades of research, we have never fully discovered what the Moon is made of,” said Professor Grande. “The Apollo missions only explored the equatorial regions on the Earth-facing side of the Moon, while other spacecraft only investigated surface colour or searched for water and heavy elements. D-CIXS will provide the first global X-ray map of the elements that make up the Moon.

“X-rays from the Sun cause atoms in the lunar surface to fluoresce – rather like the gas in the fluorescent tubes that light our offices and homes – so that they emit X-rays of their own. D-CIXS will measure the Moon’s composition by detecting these X-rays coming from the lunar surface. The precise energy carried by each X-ray tells us the element that is emitting it.

“This information will provide us with vital clues to help us understand the origins of our Moon.”

In order to create an instrument that is the size of a toaster and weighs just 4.5 kilograms, the D-CIXS team had to miniaturise the components and develop new technology such as novel X-ray detectors – based on new swept charge devices (similar to the charged couple devices found in digital cameras) and microfabricated collimators with walls no thicker than a human hair.

Other UK institutions involved in D-CIXS are:- University of Sheffield, Queen Mary University of London, Natural History Museum, Armagh Observatory, University College London, Mullard Space Science Laboratory and the University of Manchester.

Dr. Sarah Dunkin of CCLRC-RAL and University College London is also a Co-Investigator on the SMART-1 Infrared Spectrometer (SIR), which will search for ice and produce a global map of lunar minerals.

The main UK industrial involvement is by SEA Group Ltd, who helped to develop the Ka-band Telemetry and Telecommand Experiment (KaTE) which will test more efficient communication techniques for deep space missions.

Original Source: RAS News Release

Image credit: ESA

The launch date for the European Space Agency’s SMART-1 spacecraft has been set for early morning of September 28. Earlier this week the spacecraft was attached to the top of an Ariane 5 rocket at the Kourou spaceport in French Guiana. When it finally does get into space, SMART-1 will use its ion engine to slowly spiral away from the Earth until it gets captured by the gravity of the Moon. Once its in orbit around the Moon, it will map the chemical composition of the surface with greater detail than ever done before. It will also search for evidence of water ice at the Moon’s south pole.

The launch date for ESA’s SMART-1 mission to the Moon is confirmed as during the night of 27-28 September 2003.

The ‘launch window’ will be 8:02 p.m. to 8:21 p.m. on Saturday, 27 September, local time in Kourou, French Guiana, and 1:02 a.m. to 1:21 a.m. on Sunday, 28 September, CEST.

Earlier this week, the SMART-1 spacecraft completed the first 30 metres of its trip to the Moon when it was put on board its Ariane 5 launcher at the Kourou spaceport in French Guiana.

As ESA scientists and engineers watched, the spacecraft looked very small, with its Ariane 5 mounting adapter, when it was raised the 30 metres up to the top of the launcher inside the Final Assembly Building (BAF). Within an hour it was sitting on the rocket’s upper stage.

The spacecraft is pictured here being made ready for flight and having its solar panel array protection removed. The next step is to enclose the spacecraft with the 2.6-metre raising cylinder, which carries the second passenger satellite, E-Bird, on top of SMART-1.

Original Source: ESA News Release

Image credit: ESA

One significant event in the Cassini mission will be when the Huygens probe is deployed to Saturn’s largest moon Titan in early 2005. A team of scientists from the European Space Agency recently tested how their probe will perform on the long drop through Titan’s atmosphere by dropping a replica here on Earth. The mock-up was dropped from an altitude of 33 km on a balloon and it used a parachute to slow its return to Earth. ESA controllers use the descent time to calibrate the instrumentation that will communicate with the real Huygens probe when it makes its visit to Titan.

You need to have thought of almost every eventuality when landing on a distant moon in a remote corner of the Solar System. You must have tested your spacecraft to its limits to be sure it will withstand the extreme conditions expected on Titan, a moon of Saturn.

Moreover, you have to gather in advance as much information as you can about the way your instruments will work in those conditions. It is only when the scientific instruments work properly that you can say your mission has been successful.

Descending through poisonous gas
In early 2005, ESA’s Huygens probe will descend through the cloak of noxious gases surrounding Titan, Saturn’s largest and most mysterious moon. An Italian-led team of European scientists and engineers have ingeniously tackled the challenges of testing the reliability, behaviour, and response of some of the probe’s instruments in actual operation ? not simulations.

Using a combination of balloon and parachute, the team had a creative way of testing a full-scale replica of the Huygens space probe ? they dropped it from 33 kilometres above the Earth! The air we breathe on Earth is very different from the poisonous smog of Titan, but Jean-Pierre Lebreton, ESA Huygens Project Scientist, says that the way in which the properties of our atmosphere change are similar to the behaviour of Titan?s atmosphere.

On 6 June 2003, the scientists gathered at the Italian Space Agency’s Trapani balloon-launch facility in Sicily. To launch the 500-kilogram gondola carrying the mock-up Huygens space probe, they used a helium balloon that fully inflated to a diameter of 100 metres (corresponding to a total volume of 400 000 cubic metres) at its maximum altitude. When the balloon reached a height of 33 kilometres, a release mechanism opened and dropped the probe.

The on-board parachute deployed to slow the probe’s fall from 40 metres per second to just 4 metres per second. At that speed, the probe floated gently back to Earth, taking about 30 minutes to complete its journey beneath the ten-metre-wide parachute. This parachute was designed to provide a fall speed very close to the one expected at Titan.

“Altimeter 1, are you receiving me?”
The flight allowed scientists to collect data under conditions which are as representative as possible in Europe of the future flight to millions of kilometres away from the Earth. In this way, they can really begin to understand the instrument characteristics very well. Scientists call this process calibration.

Not only are these training exercises important to understand the behaviour of the instruments and the data, they also contribute to building team spirit for when the real thrills start at Titan!

This drop was the fourth test flight of the Huygens instruments on Earth (the first such test took place in Spain during 1995, the following two were done in Sicily). This flight was the first to have a fully equipped Huygens mock-up, including the complete Huygens Atmospheric Structure Instrument (H-ASI) provided by Italy. Once on Titan, the purpose of H-ASI will be to study the temperature, pressure, electrical properties, and the winds in this exotic atmosphere.

A mock-up of one of the two Huygens altimeters, mounted on the replica probe was also tested during this balloon flight. The altimeters measure the probe’s height from the ground. “We have analysed the data. From what we have seen so far, the altimeter worked well,” says Lebreton. “The test makes me very confident that the two altimeters on Huygens will work well at Titan.”

“One of the other exciting and comforting aspects of this test flight was to see how good the probe was at stabilising itself during the descent when atmospheric turbulences disturbed the fall, thanks to its special parachute design. We can then confidently expect we will have a flawless drop through Titan?s atmosphere in early 2005,” says Enrico Flamini, ASI Project Manager for Huygens, responsible for this test campaign.

The scientists are now considering a final drop during 2004 over Antarctica. This location is the one on Earth that best resembles Titan’s atmospheric conditions, in terms of pressure, electrical properties, and temperatures. Titan’s temperatures can drop to about ?180?C!

Original Source: ESA News Release