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  • richardmitnick 11:32 am on November 27, 2015 Permalink | Reply
    Tags: , , ESA Lisa Pathfinder,   

    From ESA: “Flight teams prepare for LISA Pathfinder liftoff” 

    ESASpaceForEuropeBanner
    European Space Agency

    27 November 2015

    ESA LISA Pathfinder

    Following months of intensive training, mission controllers for the LISA Pathfinder gravitational wave detection testbed will complete a final rehearsal tomorrow, ensuring that all is ready for the journey to space.

    Next week, a Vega rocket will lift LISA Pathfinder into space on a mission that will test-drive the hardware for detecting gravitational waves – ripples in spacetime, the very fabric of the Universe.

    Vega is expected to lift off at 04:15 GMT on 2 December from Europe’s Spaceport in Kourou, beginning a 105-minute ride to space.

    LISA Pathfinder will separate from the final stage at around 06:00 GMT, moments before transmitting its first signals to the ground.

    For engineers at ESA’s ESOC control centre in Darmstadt, Germany, separation is a crucial moment in the demanding first days in orbit.

    Teams will establish control, start switching on the control systems and begin taking the craft through a series of health checks.

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    LISA Pathfinder’s journey from launch to its final destination, around the L1 Sun–Earth Lagrangian point some 1.5 million km away from Earth towards the Sun

    Insert: LISA Pathfinder will be launched in December 2015 on a Vega rocket from Europe’s Spaceport in French Guiana. Vega will place LISA Pathfinder into an elliptical orbit, with a perigee (closest approach) of 200 km, apogee (furthest approach) of 1540 km, and inclination of about 6.5º. Then, when Vega’s final stage is jettisoned, LISA Pathfinder will continue under its own power, beginning a series of six apogee-raising manoeuvres. These manoeuvres will be completed two weeks after launch.

    After this, LISA Pathfinder will cruise towards its final orbiting location. A month after its final burn, it will jettison its propulsion module and continue its journey before settling into an orbit around the L1. The entire journey, from launch to arrival at the operational orbit around L1, will take about eight weeks.

    Experts spanning a range of specialities, including mission operations, flight dynamics, software and ground stations, will work 24 hours a day for the first dozen days to ensure LISA Pathfinder is operating as it should and to send it towards its final destination.

    It will conduct its mission circling the ‘L1 Lagrange point’, a virtual position in space some 1.5 million kilometres from Earth in the direction of the Sun.

    “LISA Pathfinder is a complex mission,” notes flight director Andreas Rudolph. “Even after we’re safely in space, we will have to make seven or eight thruster burns in the first 10 days to take it as safely as possible through Earth’s radiation belts and get it onto the correct trajectory.

    “We won’t arrive at around L1 until late in January, and until then teams will be working intensively to ensure that the thruster burns go as planned, that our navigation is correct and that we ensure the instruments and all flight systems are working normally.”

    LISA Pathfinder’s science mission is expected to last 180 days (updates and details on the science and technology objectives).

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    Team training

    By launch day, the 80-plus people on the mission teams will have completed many months of training, including a lengthy series of simulations using the Main Control Room at ESOC.

    “Throughout 2015, the mission team have spent many hours sitting ‘on console’, using simulation software and real flight hardware to practise all stages of the mission,” says spacecraft operations manager Ian Harrison.

    “We’ve practised routine situations as well as contingencies, so that everyone knows what to do if something goes wrong.”

    Several of the trainings were ‘live’, with mission control systems at ESOC connected to LISA Pathfinder as it was being completed at a test centre near Munich. Many simulations also included the science operations teams responsible for the instruments.

    The mission will initially be followed by ESA ground stations at Kourou in French Guiana, Perth in Australia, and Maspalomas in Spain, as well as by a dedicated antenna at Italy’s Malindi station in Kenya.

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    Kourou tracking station

    On launch day, grabbing the first signal from LISA Pathfinder will be particularly complicated because the spacecraft uses higher-frequency X-band radio signals for its communications. This produces a much narrower beam than the traditional lower-frequency S-band radio waves normally used for missions to low Earth orbit.

    “X-band is typical for a craft that will voyage 1.5 million kilometres from Earth,” says ground operations engineer Fabienne Delhaise, “but is not common for satellites in low orbit, which is where LISA Pathfinder starts out.”

    “This means our ground stations must point especially accurately and use a special adapter to catch signals just after separation, when the craft is still near Earth.”

    Later, once its orbit rises above about 45 000 km, mission controllers will use ESA’s powerful deep-space radio dishes in Australia, Spain and Argentina, which are designed just for such distant signalling.

    “Our mission teams are ready, the tracking stations are ready and our carefully developed ground systems are ready,” says Paolo Ferri, who heads ESA’s mission operations.

    “We’re excited about the technology on board and we’re looking forward to a smooth launch and an excellent start to this fantastic mission.”

    See the full article here .

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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 12:51 pm on November 17, 2015 Permalink | Reply
    Tags: , ESA Lisa Pathfinder, ,   

    From Nature: “Freefall space cubes are test for gravitational wave spotter” 

    Nature Mag
    Nature

    17 November 2015
    Elizabeth Gibney

    There is a lot riding on the LISA Pathfinder mission, an ambitious effort to test whether intricate technology designed to detect ripples in space-time can be deployed in space.

    ESA LISA Pathfinder
    LISA

    Scheduled to launch on 2 December, the spacecraft is a long-awaited test-drive for a future €1-billion (US$1.1-billion) space observatory planned by the European Space Agency (ESA). The follow-up mission would track the largest objects in the Universe, including mergers between supermassive black holes and collisions between galaxies, by the space-time ripples that they create.

    First predicted by Albert Einstein almost exactly 100 years ago as part of his general theory of relativity (see nature.com/relativity100), such gravitational waves have never been observed directly — let alone used to study the cosmos. There are already Earth-based observatories hunting these waves, but a space-based one would search for waves at the opposite end of the spectrum.

    Advanced Ligo
    MIT/Caltech Advanced LIGO

    “It’s like having a radio telescope as well as an optical one,” says Karsten Danzmann, director of the Max Planck Institute for Gravitational Physics in Hanover, Germany, and co-principal investigator for the Pathfinder mission. “The part of the Universe you see is completely different.”

    The final space-based observatory will try to spot the stretching and compressing of space by bouncing laser beams between three masses floating in freefall, each separated from the others by some 5 million kilometres. Because the masses would be protected from all other external forces, only a gravitational wave should disrupt the synchrony of their falling motion — a disturbance that would affect laser frequency.

    The LISA Pathfinder (named after the Laser Interferometer Space Antenna, the concept behind the gravitational-wave observatory) is a smaller-scale test of this ultimate plan. With a pricetag of €400 million, it uses just two masses — each a 2-kilogram cube of gold and platinum — separated by a mere 38 centimetres, which allows them to fit inside the same spacecraft.

    Unlike that of the observatory that it is designed to test-drive, this set-up is not sensitive enough to detect gravitational waves — instead, its purpose is to show that the masses can be completely isolated, and that any deviations in their relative motion can be measured with picometre accuracy. “We’re missing out the 5 million kilometres, but so what?” says Paul McNamara, the mission’s project scientist. “Pretty much everything that could affect our ability to measure gravitational waves is here.”

    From the time of Pathfinder’s launch from ESA’s spaceport in Kourou, French Guiana, to the end of its subsequent eight-week journey, the masses will stay pinned to their housing deep inside the craft. But on arrival in orbit around a stable point between the Sun and Earth called Lagrange point 1, or L-1, about 1.5 million kilometres away, the cubes will be gently released to float within the spacecraft (see ‘Precision lab in space’).

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    Once in freefall, “the challenge is to isolate this little cube from everything around it, so the only thing it sees is space-time”, says McNamara. Expected disturbances are pressure from solar radiation and stray magnetic fields; the equipment is so precise that it should detect even a force equal to the weight of a small bacterium on Earth.

    As a high-precision laboratory in space, the LISA Pathfinder is unlike anything that ESA has done before, says Tim Sumner, an astrophysicist at Imperial College London who led the team that constructed one of the craft’s protection mechanisms.

    Another unusual element is that the major cargo — the cubes — will define the craft’s trajectory, rather than vice versa. As they orbit around L-1 and fall in microgravity, Pathfinder will deploy microthrusters that are so gentle, it would take around 1,000 to lift a piece of paper on Earth. The thrusters will monitor the cubes’ positions, ensuring that the craft hovers around the cubes without letting them touch its sides. Such a set-up required the teams who built the instruments and the engineers who made the craft to work together to an unprecedented degree, says Sumner.

    These complexities go a long way towards explaining why the launch has taken so long to orchestrate, says Stefano Vitale, a physicist at the University of Trento in Italy, and a principal investigator for the Pathfinder mission; Pathfinder was approved by ESA in 2000 and originally intended for launch in 2006. “Coarsely speaking, I think people underestimated the difficulty,” says Vitale. “But that’s why you have a Pathfinder.”

    The final step in the planned mission will test Pathfinder’s limits by instructing onboard instruments to tweak the internal temperature and magnetic and electrostatic fields to see how such changes affect the cubes. “We want to learn everything we can about the physics of a free-floating body, and everything we learn will feed back into design of the future mission,” says McNamara.

    However, some opportunistic ESA scientists are already thinking about how Pathfinder’s instruments could be used to inform other problems once its main mission, which could take up to a year, is complete. Measurement of the gravitational constant, known as Big G, for example, should fall naturally out of Pathfinder’s data, Sumner says. Because the true value of Big G is disputed, a fresh measurement from space would provide useful perspective.

    To get a higher precision measurement, ESA may also consider extending the mission — although Sumner says that scientists would only request this after Pathfinder has proved itself, a few months in. He and his colleagues have also discussed using the craft’s thrusters to send it to a spot known as a saddle point, where the gravitational pulls of Earth and the Sun cancel each other out. This could reveal how gravity behaves at its lowest level possible in the Solar System, with little extra cost. Few scientists doubt that Einstein’s theories hold, says Sumner, but it would be interesting to do the test nonetheless.

    Vitale, however, points out that it is important for researchers to stay focused on the mission’s immediate goal. “Our main objective is to demonstrate freefall,” he says, “and we don’t want to be distracted from that.”

    See the full article here .

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    Nature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

     
  • richardmitnick 1:40 pm on September 28, 2015 Permalink | Reply
    Tags: , , ESA Lisa Pathfinder,   

    From ESA: “If our eyes could see gravitational waves” 

    ESASpaceForEuropeBanner
    European Space Agency

    28/09/2015

    1
    This image is from a simulation of two black holes merging and the resulting emission of gravitational radiation, published by NASA in 2012.

    Picture the scene: two gigantic black holes, each one a good fraction of the size of our Solar System spiralling around each other. Closer and closer they draw until they touch and merge into a single, even more gigantic gravitational prison.

    But what would you actually see? For such a cataclysmic event, it might all take place with remarkable stealth because black holes by their very nature emit no light at all. Rather than light, it would be a different story if our eyes could see gravitational waves.

    This is what the merger of two black holes would look like. It is a computer simulation of the gravitational waves that would ripple away from the titanic collision, a bit like the ripples on a pond when a pebble drops into the water.

    In the case of gravitational waves, the disturbances are not in water but in the spacetime continuum. This is the mathematical ‘fabric’ of space and time that Albert Einstein used to explain gravity.

    Gravitational radiation has been indirectly observed but never seen directly. Its detection would open a whole new way of studying the Universe. As a result, astronomers are working on both ground-based and space-based detectors. And it is a real challenge.

    Gravitational radiation is incredibly difficult to measure. The ripples cause atoms to ‘bob’ about to just 1 part in 1000 000 000 000 000 000 000. Building a detector to notice this is like measuring the distance from Earth to the Sun to the accuracy of the size of a hydrogen atom.

    Following decades of technology development and experiments, detectors on the ground are nearing the required sensitivity. The first detections are expected in the next few years. But these detectors can see only half of the picture. The mass of the colliding black holes determines the frequency of the gravitational radiation.

    The merger of small black holes, each about a few times the mass of the Sun, will create high-frequency gravitational waves that could be seen from the ground. But the giant black holes that sit at the heart of galaxies with masses of a million times that of the Sun will generate gravitational waves of much lower frequency. These cannot be detected with ground-based systems because seismic interference and other noise will overwhelm the signals. Hence, spaceborne observatories are needed.

    ESA has selected the gravitational Universe as the focus for the third large mission in the Cosmic Vision plan, with a launch date of around 2034.

    Unlocking the gravitational Universe will require a highly ambitious mission. In preparation, ESA will launch LISA-Pathfinder this November to test some of the essential technologies needed to build confidence in future spaceborne gravitational wave observatories.

    ESA LISA Pathfinder
    LISA Pathfinder

    See the full article here .

    Please help promote STEM in your local schools.

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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 6:41 am on August 8, 2015 Permalink | Reply
    Tags: , , ESA Lisa Pathfinder,   

    From ESA: LISA Video 

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    European Space Agency

    LISA Pathfinder’s name (Laser Interferometry Space Antenna) clearly indicates the role of precursor that this mission plays. Its goal is for preparing the technology to test gravitational-wave detection in space. This will open new doors for our understanding of the universe. LISA Pathfinder will be launched before the end of the year on a Vega from Kourou in French Guiana. This video shows LISA Pathfinder in preparation near Munich in Germany.

    Watch, enjoy, learn.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 7:06 am on February 28, 2015 Permalink | Reply
    Tags: , ESA Lisa Pathfinder,   

    From BBC: “Lisa Pathfinder: ‘Exquisite’ gravity probe leaves UK” 

    BBC
    BBC

    28 February 2015
    Jonathan Amos

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    The Lisa Pathfinder modules: The science satellite sits atop its propulsion unit. The Lisa Pathfinder contract represented a watershed for UK industry in space.

    British industry has completed construction of the modules that make up the Lisa Pathfinder satellite.

    ESA LISA Pathfinder
    LISA Pathfinder

    This remarkable probe will test the key technologies needed to detect gravitational waves in space. If that can be done, it would open up black holes and other astrophysical phenomena to a completely new era of scientific investigation. Lisa Pathfinder’s modules were assembled at the UK arm of Airbus Defence and Space. They leave for Germany on Monday, to go to the IABG consultancy just outside Munich for some final integration and testing. From there, they will be shipped to Kourou in French Guiana for a rocket launch in September.

    The European Space Agency (ESA) mission is the first to be led industrially from the UK since the Giotto satellite was sent to fly past Comet Halley in 1986. As such, Lisa Pathfinder represents a watershed moment for the British space sector. “There were some lean years after Giotto, but you can see the momentum we now have. We’re at the start of something really special,” Andy Stroomer, from Airbus in Stevenage, told BBC News.

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    The aim is to put two gold-platinum blocks in free-fall and then track their relative movement using lasers

    Still being worked on in Pathfinder’s big cleanroom are ESA projects worth more than a billion euros in total. These are satellites to visit the Sun and observe the Earth. And just a stone’s throw away is a brand new facility under construction which will house the assembly of the robotic rover that Europe plans to send to the surface of Mars in 2019. The two parts of Lisa Pathfinder heading out of Stevenage comprise the main satellite and the propulsion unit that will push it away from Earth to begin its mission. At the moment, the spacecraft’s all-important science instrument package is absent. This will be installed in the coming weeks at IABG. Lisa Pathfinder is a demonstrator for a future satellite idea that Europe hopes to launch in the 2030s. This is a concept known as the Laser Interferometric Space Antenna (LISA), which will endeavour to detect gravitational waves.

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    [Albert] Einstein’s theory of general relativity predicts that these ripples in the fabric of space-time should be generated when massive objects like black holes coalesce and merge. And although the signal is expected to be extremely faint, it should still be apparent to an ultra-stable, super-fine measurement system. The Pathfinder’s job is to prove the metrology. To do this, it will try to put two small gold-platinum blocks into a perfect free-fall and then track their relative movement using lasers. The intention is to get these blocks following a line that is defined only by gravity. To do that requires that all other forces that might interfere with the demonstration are removed. This means, for example, carefully controlling the influence of temperatures and magnetic fields. Even the vacuum state will introduce “noise” into the system if some residual gas molecules are allowed to collide with the blocks. The experiment has been designed such that disturbances to the blocks as small as just a few picometers should be noticed. One picometer is a small fraction of the width of a hydrogen atom.

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    Coalescing massive bodies should radiate gravitational waves at the speed of light

    Cesar Garcia is the European Space Agency’s project manager on Lisa Pathfinder. He describes the satellite as perhaps the most exquisite ever built. He said: “The final objective is to be convinced that we can achieve and then measure a pure geodesic motion. That is, a motion subject only to the Riemann tensor – to the curvature of space-time. This is what we aim to do – to work on the noise sources, to suppress the noise sources, to learn the noise sources; and then what remains must be a straight line.”

    It is in these conditions of perfect free-fall that one would look for gravitational waves. Lisa Pathfinder itself cannot sense them, however. The ripples produced by merging black holes are at too low a frequency.

    But if the methodology is scaled up as proposed for the Lisa mission proper, with precision measurement of blocks separated by millions of km, the very delicate signal ought then to show itself.
    David Southwood was the director of science at Esa in 2004 when the agency contracted Airbus to build Lisa Pathfinder. Now on the steering board of the UK Space Agency, he was present on Friday to see the spacecraft modules packed up ready for the transfer to IABG. He told BBC News: “It’s a fascinating mission right at the frontier of understanding and it could lead one day to the detection of gravitational waves in space. But these technologies don’t need to be used just to measure gravity. It’s in the nature of things that once you’ve pushed something to the extreme for a particular purpose, another smart person is inspired to take those ideas and put them to use in another application. What that is, no-one can predict. That’s the beauty of it.”

    See the full article here.

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