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Thread: ESA's LISA Pathfinder

  1. #1
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    ESA's LISA Pathfinder

    ESA's LISA Pathfinder was launched today to look for gravitational waves.

    http://www.spacedaily.com/reports/LI...ation_999.html

    LISA Pathfinder will test the extraordinary technology needed to observe gravitational waves from space. At its core is a pair of identical 46 mm gold-platinum cubes separated by 38 cm, which will be isolated from all external and internal forces acting on them except one: gravity.

    The mission will put these cubes in the purest free-fall ever produced in space and monitor their relative positions to astonishing precision, laying the foundations for gravitational wave observatories in space.

    Such future missions will be key partners to the ground sites already searching for these elusive cosmic messengers. Space and ground experiments are sensitive to different sources of gravitational waves, both opening up new possibilities to study some of the most powerful phenomena in the Universe.

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    A bit of background and why it is going to the First Lagrangian Point of the Earth-Sun system

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    One key component of the mission is from NASA. On board is the state-of-the-art Disturbance Reduction System (DRS), a thruster technology developed at NASA's Jet Propulsion Laboratory, Pasadena, California.

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    Quote Originally Posted by selvaarchi View Post
    ESA's LISA Pathfinder was launched today to look for gravitational waves.

    http://www.spacedaily.com/reports/LI...ation_999.html
    Actually the text you quoted says it was launched to test the technology that will be needed to look for gravitational waves. That suggests that the pathfinder mission is not expected to detect gravitational waves.

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    Quote Originally Posted by Amber Robot View Post
    Actually the text you quoted says it was launched to test the technology that will be needed to look for gravitational waves. That suggests that the pathfinder mission is not expected to detect gravitational waves.
    My apologizes. You are correct. In fact it says that in the first line of the text I quoted. "LISA Pathfinder will test the extraordinary technology needed to observe gravitational waves from space. At its core is a pair of identical 46 mm gold-platinum cubes separated by 38 cm, which will be isolated from all external and internal forces acting on them except one: gravity."

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    The primary mission of LPF is to test the internal sensors for picking up movement of those cubes in the craft at the picometer scale and firing microthrusters just right to compensate that.

    eLISA, the full-scale version of the experiment that will actually look for gravitational waves in the 2030s, will consist of three such satellites that are placed in a triangle spaced 1 million km apart, at a position about 20° behind Earth. The three satellites will use laser communications terminals to keep themselves not just relative to the internal cubes but also relative to each other in perfect position. Gravitational waves are then detected through sudden "changes" in position of the cubes (to keep it simple).

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    Quote Originally Posted by kato View Post
    The primary mission of LPF is to test the internal sensors for picking up movement of those cubes in the craft at the picometer scale and firing microthrusters just right to compensate that.

    eLISA, the full-scale version of the experiment that will actually look for gravitational waves in the 2030s, will consist of three such satellites that are placed in a triangle spaced 1 million km apart, at a position about 20° behind Earth. The three satellites will use laser communications terminals to keep themselves not just relative to the internal cubes but also relative to each other in perfect position. Gravitational waves are then detected through sudden "changes" in position of the cubes (to keep it simple).
    The first talk I heard about the LISA space mission was in 1997, at my summer REU.

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    yes LISA was once a NASA mission, it was once a joint NASA and European venture. Some of us followed it for years and sadly funding was cut in 2007-2009 to such levels that NASA canceled the mission. Follow on missions could have been launched such as the BBO or Big Bang Observer
    https://www.researchgate.net/publica..._Bang_Observer

    Back in April 2011, NASA offically announced that it would be unable to continue its LISA partnership with the European Space Agency due to funding limitations, many users on this forum were disappointed.
    ESA however very rarely cancels missions once they are approved.
    http://cosmoquest.org/forum/showthread.php?11824-LISA/
    previous thread

    http://www.universetoday.com/90970/l...gravity-waves/
    Older news item

    http://www.clarksvilleonline.com/201...er-spacecraft/
    NASA Thruster system aboard LISA Pathfinder spacecraft
    The LISA Pathfinder spacecraft is on its way to space, having successfully launched from Kourou, French Guiana (December 3rd local time/December 2nd PST). On board is the state-of-the-art Disturbance Reduction System (DRS), a thruster technology developed at NASA’s Jet Propulsion Laboratory, Pasadena, California.

    The smaller LISA-Pathfinder was the prototype mission to LISA, testing technologies for the more ambitious LISA which was to make OBSERVATIONS using gravity waves (NASA's Laser Interferometer Space Antenna ) since then European Space Agency has re-named the mission Evolved Laser Interferometer Space Antenna or ELISA
    Last edited by Launch window; 2016-Jan-03 at 11:16 AM.

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    Europe’s LISA Pathfinder mission crafted to demonstrate the ability to detect gravitational waves — theorized ubiquitous cosmic signals that have so far eluded discovery — has arrived at its operating post around the L1 Lagrange point nearly a million miles from Earth.

    http://spaceflightnow.com/2016/01/25...es-from-earth/

    he six-sided spacecraft jettisoned its propulsion module at about 1130 GMT (6:30 a.m. EST) Friday after a series of engine burns thrust LISA Pathfinder toward its work site at L1 after lifting off from French Guiana on Dec. 3.

    LISA Pathfinder’s launch aboard a European Vega rocket put the spacecraft and its fuel-laden engine section into an elliptical low-altitude orbit with a high point about 1,540 kilometers (957 miles) above Earth.

    The propulsion package attached to the base of the LISA Pathfinder science module fired six times to propel the probe farther from Earth toward the L1 libration point about 1.5 million kilometers (932,000 miles) toward the sun.

    A final 64-second maneuver by the spacecraft’s main engine Jan. 20 nudged LISA Pathfinder into a looping, halo-like orbit around L1, an imaginary point between the Earth and the sun where the gravitational pull from the two bodies balances, allowing a spacecraft to loiter there with occasional small corrections.

    LISA Pathfinder needed only one of two prescribed burns to enter orbit at L1, and ground controllers programmed the spacecraft to jettison its engine module Friday.

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    Anyone know why they jettisoned the propulsion unit?

    There has to be a logical reason, but you would have thought that having the option to correct the space crafts orbit in the future would have been a distinct advantage.
    Its never too late to have a happy childhood

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    Lisa Pathfinder Fact Sheet
    The propulsion module was then jettisoned since it would be a source of unwanted forces on the science spacecraft during science operations.
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    Skepticism enables us to distinguish fancy from fact, to test our speculations. --Carl Sagan

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    Interesting that the quest to detect gravity waves is turning out to be a race between ESA and China (the US has decided to sit this out ). Both teams are taking a different approach to tackle the challenge ☺

    It does not matter who wins as if either side detect's it, it is a win for humanity

    Sent from my SM-G900F using Tapatalk

    Oops I made a mistake. China is looking for dark matter. It is a race between the West and China as to who might explain it first.
    Last edited by selvaarchi; 2016-Jan-30 at 04:42 AM.

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    The propulsion module was then jettisoned since it would be a source of unwanted forces on the science spacecraft during science operations.
    Thanks 01101001

    BTW you probably already know this, but others might not
    http://www.01101001.com/about.html
    Its never too late to have a happy childhood

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    Quote Originally Posted by efanton View Post
    BTW you probably already know this, but others might not
    http://www.01101001.com/about.html
    I certainly didn't. Geek chic. Ha!
    Everyone is entitled to his own opinion, but not his own facts.

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    On February 5th 2016, the lock fingers that kept the two test masses on LISA Pathfinder secure during the launch and cruise phase were successfully unlocked. As planned, the two cubes are still attached to the spacecraft via an additional mechanism that will hold them in place until mid February, as the teams carry on with the spacecraft and payload commissioning.

    http://www.spacedaily.com/reports/Fi...cubes_999.html

    With the spacecraft settling into its new home, teams from ESA, Airbus Defence and Space (the prime contractor) and the institutes that provided the payload hardware continue to perform tests on the various systems, subsystems and instruments in preparation for when science operations will begin on 1 March.

    At the centre of the spacecraft is the LISA Technology Package, which houses the two test masses that will be put in the most precise free-fall motion ever obtained in space. The position and attitude of these two identical gold-platinum cubes is monitored by a laser interferometer to estimate how much their motion is affected by other forces beyond gravity.

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    Congratulations ESA ESA’s LISA Pathfinder mission has demonstrated the technology needed to build a space-based gravitational wave observatory.

    http://www.esa.int/Our_Activities/Sp...s_expectations

    Results from only two months of science operations show that the two cubes at the heart of the spacecraft are falling freely through space under the influence of gravity alone, unperturbed by other external forces, to a precision more than five times better than originally required.

    In a paper published today in Physical Review Letters, the LISA Pathfinder team show that the test masses are almost motionless with respect to each other, with a relative acceleration lower than 1 part in ten millionths of a billionth of Earth’s gravity.

    The demonstration of the mission’s key technologies opens the door to the development of a large space observatory capable of detecting gravitational waves emanating from a wide range of exotic objects in the Universe.

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    It looks like the main L.I.S.A mission is GO!

    https://www.universetoday.com/136133...n-going-space/

    The ESA recently decided to move forward with its LISA mission, a trio of satellites that will be the first space-based gravitational wave detector.
    Gravitational Wave Detection is Going to Space
    LISA is On!
    https://forum.cosmoquest.org/showthr...Going-to-Space

    around the web
    https://phys.org/news/2017-06-gravit...t-hunting.html
    http://www.dailymail.co.uk/sciencete...raft-2034.html
    http://www.scienceworldreport.com/ar...le-planets.htm
    https://room.eu.com/news/lisa-gets-green-light-from-esa

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    We now have said bye to LISA Pathfinder as it has been switched off but the good news is it is all go for LISA which will be launched in 2034.

    http://www.aei.mpg.de/2083822/lpfmissionsende

    After 16 months of science measurements an international team deactivated the LISA Pathfinder satellite on the evening of the 18th of July 2017. The gravitational-wave laboratory in space powered down after receiving the last commands in the evening and circles the Sun on a safe parking orbit. LISA Pathfinder has tested key technologies for LISA, the future gravitational-wave observatory in space, and has demonstrated their operative readiness. LISA is scheduled to launch into space in 2034 as an ESA mission and will “listen” to the entire Universe by measuring low-frequency gravitational waves.

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    2034??

    Why so long? Are they still inventing the technology?

    CJSF
    "Find a way to show what would happen
    If you were incorrect
    A fact is just a fantasy
    Unless it can be checked
    Make a test
    Test it out"
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  20. #20
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    Just working to the planned schedule.

    Wikipedia: Laser Interferometer Space Antenna

    In 2013, ESA selected 'The Gravitational Universe' as the theme for its L3 mission in the early 2030s. whereby it committed to launch a space based gravitational wave observatory.

    In January 2017, LISA was proposed as the candidate mission. On June 20, 2017 the suggested mission received its clearance goal for the 2030s, and was approved as one of the main research missions of ESA.
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    Skepticism enables us to distinguish fancy from fact, to test our speculations. --Carl Sagan

  21. #21
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    LISA is a large mission in the ESA Cosmic Vision program. Large missions are on a cadence of about six years. The next two missions had already been selected, so that puts the newest selection, LISA, about 18 years out. See Wikipedia: List of European Space Agency programs and missions.

    L-class missions
    L1 – JUICE, launching 2022, future – Jupiter orbiter mission, focused on studying the Galilean moons Europa, Ganymede and Callisto.
    L2 – ATHENA, launching 2028, future – X-ray space observatory mission, designed as a successor to the XMM-Newton telescope.
    L3 – LISA, launching 2034, future – the first dedicated gravitational wave space observatory mission.
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    Skepticism enables us to distinguish fancy from fact, to test our speculations. --Carl Sagan

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    LISA Pathfinder (LPF) exceeded the requirements for future gravitational-wave observatory LISA.

    http://www.aei.mpg.de/2207338/lpf-final-results

    The final results from the ESA satellite LISA Pathfinder (LPF) have been published today. Using data taken before the end of the mission in July 2017, the LPF team – including researchers from the Max Planck Institute for Gravitational Physics in Hannover and Leibniz Universität Hannover – significantly improved first results published in mid 2016. LPF now has exceeded the requirements for key technologies for LISA, the future gravitational-wave observatory in space, by more than a factor of two over the entire observation band. LISA is scheduled to launch into space in 2034 as an ESA mission and will “listen” to low-frequency gravitational waves from merging supermassive black holes in the entire Universe and tens of thousands of binary stars in our Galaxy.

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