Author Topic: ESA - LISA Pathfinder updates  (Read 28985 times)

Offline Star One

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ESA - LISA Pathfinder updates
« Reply #60 on: 02/07/2017 04:23 PM »
Scientists optimistic about prospects for LISA gravitational wave mission

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A European consortium submitted to ESA in January a proposal for the development of the Laser Interferometer Space Antenna (LISA) mission for ESA’s third large mission, or L3, competition. LISA is widely considered the leading candidate to be selected for that mission for launch likely in the early 2030s.

LISA, as proposed, will consist of three spacecraft in a triangular formation, each 2.5 million kilometers from the other two in an orbit around the sun trailing the Earth. The spacecraft would shine lasers at each other, with interferometers on each spacecraft detecting minute distance changes caused by passing gravitational waves.

The three spacecraft, with a combined mass of about 6,000 kilograms, including payload adapter, would launch on an Ariane 6 and drift to their planned orbit over the course of a year and a half. LISA would have a planned mission lifetime of four years, but with sufficient propellant on each spacecraft to operate for up to a decade.

“LISA looks like it’s going to happen. It looks like it’s on a pretty firm track,” said David Shoemaker, a senior research scientist at the Massachusetts Institute of Technology’s Kavli Institute for Astrophysics and Space Research, during a meeting of the American Physical Society (APS) here Jan. 29.

Shoemaker is chairman of the L3 Study Team, a NASA group looking at contributions NASA can make to the LISA mission. The LISA proposal submitted to ESA assumes NASA will cover 20 percent of the mission’s cost through instruments and other technologies.

Parth of the confidence of Shoemaker and other scientists is linked to the announcement a year ago of the first detection of gravitational waves, by the Laser Interferometer Gravitational-Wave Observatory (LIGO), ground-based gravitational wave detectors in Louisiana and Washington. That discovery removed any doubt that gravitational waves exist, creating confidence that a mission like LISA could also successfully detect and study gravitational waves, and do so at frequencies not possible with LIGO.

Another factor is the technical success of ESA’s LISA Pathfinder mission, a single small spacecraft launched in December 2015 to test technologies that could be used in a later LISA mission. The performance of the spacecraft, including a thruster system provided by NASA, exceeded expectations.

Those tests not only exceeded the stability expectations of the LISA Pathfinder mission, but also approached the requirements for the full-fledged LISA mission. “This was a successful demonstration of drag-free control at a level necessary for a LISA-type gravitational wave observatory,” said Charles Dunn of JPL, project technologist for the disturbance reduction system flown on LISA Pathfinder, at the APS meeting Jan. 28.

- See more at: http://spacenews.com/scientists-optimistic-about-prospects-for-lisa-gravitational-wave-mission/#sthash.dcogrTj4.dpuf
« Last Edit: 02/07/2017 04:27 PM by Star One »

Offline Star One

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Re: ESA - LISA Pathfinder updates
« Reply #61 on: 04/17/2017 08:03 PM »
NASA Team Explores Using LISA Pathfinder as 'Comet Crumb' Detector
LISA Pathfinder, a mission led by ESA (the European Space Agency) with contributions from NASA, has successfully demonstrated critical technologies needed to build a space-based observatory for detecting ripples in space-time called gravitational waves. Now a team of NASA scientists hopes to take advantage of the spacecraft's record-breaking sensitivity to map out the distribution of tiny dust particles shed by asteroids and comets far from Earth.

Most of these particles have masses measured in micrograms, similar to a small grain of sand. But with speeds greater than 22,000 mph (36,000 kph), even micrometeoroids pack a punch. The new measurements could help refine dust models used by researchers in a variety of studies, from understanding the physics of planet formation to estimating impact risks for current and future spacecraft.


In a proof-of-concept study, NASA scientists are exploring using ESA’s (the European Space Agency) LISA Pathfinder spacecraft as a micrometeoroid detector. When tiny particles shed by asteroids and comets impact LISA Pathfinder, its thrusters work to quickly counteract any change in the spacecraft's motion. Researchers are monitoring these signals to learn more about the impacting particles.
Credits: NASA's Goddard Space Flight Center
Download HD video and additional visuals from NASA's Scientific Visualization Studio
"We've shown we have a novel technique and that it works," said Ira Thorpe, who leads the team at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "The next step is to carefully apply this technique to our whole data set and interpret the results."

The mission's primary goal was to test how well the spacecraft could fly in formation with an identical pair of 1.8-inch (46 millimeter) gold-platinum cubes floating inside it. The cubes are test masses intended to be in free fall and responding only to gravity.

The spacecraft serves as a shield to protect the test masses from external forces. When LISA Pathfinder responds to pressure from sunlight and microscopic dust impacts, the spacecraft automatically compensates by firing tiny bursts from its micronewton thrusters to prevent the test masses from being disturbed.   

Scientists call this drag-free flight. In its first two months of operations in early 2016, LISA Pathfinder demonstrated the process with a precision some five times better than its mission requirements, making it the most sensitive instrument for measuring acceleration yet flown. It has now reached the sensitivity level needed to build a full multi-spacecraft gravitational wave observatory.

"Every time microscopic dust strikes LISA Pathfinder, its thrusters null out the small amount of momentum transferred to the spacecraft," said Goddard co-investigator Diego Janches. "We can turn that around and use the thruster firings to learn more about the impacting particles. One team's noise becomes another team's data."

Much of what we know about interplanetary dust is limited to Earth's neighborhood, thanks in large part to NASA's Long Duration Exposure Facility (LDEF). Launched into Earth orbit by the space shuttle Challenger in April 1984 and retrieved by the space shuttle Columbia in January 1990, LDEF hosted dozens of experiments, many of which were designed to better understand the meteoroid and orbital debris environment.

The different compositions, orbits and histories of different asteroids and comets naturally produce dust with a range of masses and velocities. Scientists suspect the smallest and slowest particles are enhanced in Earth's neighborhood, so the LDEF results are not representative of the wider solar system.

"Small, slow particles near a planet are most susceptible to the planet's gravitational pull, which we call gravitational focusing," Janches said. This means the micrometeoroid flux near Earth should be much higher than that experienced by LISA Pathfinder, located about 930,000 miles (1.5 million kilometers) closer to the sun.

To find the impacts, Tyson Littenberg at NASA's Marshall Space Flight Center in Huntsville, Alabama, adapted an algorithm he originally developed to search for gravitational waves in data from the ground-based detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO), located in Livingston, Louisiana, and Hanford, Washington. In fact, it was one of many algorithms that played a role in the discovery of gravitational waves by LIGO, announced in February 2016.

"The way it works is that we come up with a guess of what the signal might look like, then study how LIGO or LISA Pathfinder would react if this guess were true," Littenberg explained. "For LIGO, we're guessing about the waveform, the peaks and valleys of the gravitational wave. For LISA Pathfinder, we're guessing about an impact."

To map out the probability of likely sources, the team generates millions of different scenarios describing what the source might be and compares them to what the spacecraft actually detects.

In response to an impact, LISA Pathfinder fires its thrusters to counteract both the minute "push" from the strike and any change in the spacecraft's spin. Together, these quantities allow the researchers to determine the impact's location on the spacecraft and reconstruct the micrometeoroid's original trajectory. This may allow the team to identify individual debris streams and perhaps relate them to known asteroids and comets.

"This is a very nice collaboration," said Paul McNamara, the LISA Pathfinder project scientist at ESA's Directorate of Science in Noordwijk, the Netherlands. "This is data we use for doing our science measurements, and as an offshoot of that, Ira and his team can tell us about microparticles hitting the spacecraft."

Its distant location, sensitivity to low-mass particles, and ability to measure the size and direction of impacting particles make LISA Pathfinder a unique instrument for studying the population of micrometeoroids in the inner solar system. But it's only the beginning.

"This is a proof of concept, but we'd hope to repeat this technique with a full gravitational wave observatory that ESA and NASA are currently studying for the future," said Thorpe. "With multiple spacecraft in different orbits and a much longer observing time, the quality of the data should really improve."

LISA Pathfinder is managed by ESA and includes contributions from NASA Goddard and NASA's Jet Propulsion Laboratory in Pasadena, California. The mission launched on Dec. 3, 2015, and began orbiting a point called Earth-sun L1, roughly 930,000 miles (1.5 million km) from Earth in the sun's direction, in late January 2016.

LISA stands for Laser Interferometer Space Antenna, a space-based gravitational wave observatory concept that has been studied in great detail by both NASA and ESA. It is a concept being explored for the third large mission of ESA's Cosmic Vision Plan, which seeks to launch a gravitational wave observatory in 2034.

Banner image: An illustration of LISA Pathfinder on its way to Earth-sun L1. Credit: ESA/C. Carreau

https://www.nasa.gov/feature/goddard/2017/nasa-team-explores-using-lisa-pathfinder-as-comet-crumb-detector

Offline bolun

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Re: ESA - LISA Pathfinder updates
« Reply #62 on: 06/20/2017 08:12 PM »
LISA Pathfinder to conclude trailblazing mission

http://sci.esa.int/lisa-pathfinder/59238-lisa-pathfinder-to-conclude-trailblazing-mission/

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After sixteen months of science operations, LISA Pathfinder will complete its mission on 30 June, having successfully demonstrated the technology to build ESA's future space observatory of gravitational waves.

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As LISA Pathfinder approaches the end of its successful technology demonstration mission, ESA's Science Programme Committee has selected today the Laser Interferometer Space Antenna (LISA) as the third large mission (L3) in ESA's Cosmic Vision plan. LISA is a space-based observatory of gravitational waves consisting of a constellation of three spacecraft, with launch planned for 2034.

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LISA Pathfinder operations were split between the two experiments. Both thruster technologies have now been validated and will benefit future space projects such as large space observatories, or missions involving multiple spacecraft flying in formation.

The mission will continue taking data until 30 June, with a final experiment that will be pushing the precision limits of the test mass grabbing and releasing mechanisms – something of great importance for LISA. Then, after a series of final operational tests, the last command will be sent on 18 July.

A preliminary de-orbiting manoeuvre was already performed in April, nudging the spacecraft away from its orbit around the first Sun-Earth Lagrange point, L1, and towards a long-term stable parking orbit around the Sun.
« Last Edit: 06/20/2017 08:15 PM by bolun »

Offline bolun

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Re: ESA - LISA Pathfinder updates
« Reply #63 on: 07/04/2017 07:55 AM »
LISA Pathfinder still hard at work

http://blogs.esa.int/rocketscience/2017/06/30/lisa-pathfinder-still-hard-at-work/

LISA Pathfinder sails toward the sun

http://blogs.esa.int/rocketscience/2017/07/03/lisa-pathfinder-sails-toward-the-sun/

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On 18 July, the LPF mission will conclude with the final commands sent to switch off the on-board transmitter. Since April, the mission operations team in Darmstadt have been working to ensure a safe and smooth end-of-life for this fantastic technology demonstration spacecraft.

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For disposal, the spacecraft has already performed a de-orbit manoeuvre to leave its Lagrangian orbit and start to drift ahead of the Earth in a heliocentric orbit around the Sun. The spacecraft now has an orbital period a few days shorter than that of the Earth, keeping the spacecraft safely out of the way and drifting serenely around the Sun.

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30 June marked the end of the science mission ...

Offline FutureSpaceTourist

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Re: ESA - LISA Pathfinder updates
« Reply #64 on: 07/14/2017 07:50 AM »
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LISA PATHFINDER: BAKE, RATTLE AND ROLL
13 July 2017

The final days of the LISA Pathfinder mission are some of the busiest, as controllers make final tests and get ready to switch off the gravitational pioneer next Tuesday.

Following 16 months of scientific effort, LISA Pathfinder completed its main mission on 30 June, having demonstrated the technology needed to operate ESA’s future LISA space observatory to study gravitational waves – ripples in spacetime predicted by Albert Einstein in his General Theory of Relativity.

The LISA mission will comprise three spacecraft orbiting some 2.5 million km apart in a triangular formation, with their ‘test masses’ isolated from all external forces bar gravity and linked by laser beams.

With the required sensitivity fully proven by LISA Pathfinder, teams are now using the spacecraft’s last days to conduct a series of technical tests on components and devices, making full use of every remaining minute.

“These tests will give us a better grasp of the craft’s behaviour and provide valuable feedback to the manufacturers about the characteristics of their equipment, in both routine and unusual conditions,” says spacecraft operations manager Ian Harrison.

“The gravitational wave detectors work by measuring the changing separation of two cubes that are in free-fall. Changes in the spacecraft’s state or any movement may interfere with the measurements, and we want to better understand these for the future mission.”

In addition to satellite movement, the delicate cubes on LISA Pathfinder can be influenced by variations in their environment, such as in temperature and magnetic interference.

Baking, rattling and rolling

Working at ESA’s mission control centre in Darmstadt, Germany, the controllers have been conducting daily tests since the mission formally ended its normal phase on 30 June. These could not be performed before because meeting the science goals required a very stable and ‘quiet’ environment.

Engineers have commanded the craft to turn to assess thermal effects on its systems, particularly the micropropulsion system, from solar illumination.

Repeating thermal tests previously performed on the ground will help to improve procedures for the future LISA mission.

Other tests are analysing the effect of magnetic interference, from the operation of pressure regulation valves in the cold-gas thruster system, on the spacecraft’s magnetic momentum, external forces and test mass control.

The teams have also been pushing the micropropulsion system and test-mass electrostatic sensing and control systems to their limits.

Spacecraft performance data have been recorded since the time of launch in December 2015 up to these last experiments, to determine the rate of hardware degradation in the harsh environment of space.

Boosting European industry

Results from this test series will be available to European hardware manufacturers for incorporation into future designs.

“These tests will help to eliminate variables that might influence the science results from future ESA missions, such as Euclid and LISA, and help reduce risk in their development,” says flight director Andreas Rudolph.

“The tests could go wrong for many reasons and might cause loss of data, or adversely affect the spacecraft, so they were not considered during the main technology demonstration phase of the mission.

“This is a great opportunity to test hardware in flight, with no effect on the mission objectives or final activities.”

Ready for lights out

Ground teams are getting ready to ‘passivate’ LISA Pathfinder, eliminating radio transmissions from the spacecraft and switching off most of the units.

In April, the spacecraft used its thrusters over five days to nudge itself into a safe orbit around the Sun, minimising any probability that it will return to the vicinity of Earth or Moon in the next 100 years, in line with ESA's requirement for space debris mitigation.

The final command switching off the craft is planned for around 18:00 GMT on 18 July.

“Before LISA Pathfinder, gravitational wave astronomy from space was a theoretical possibility, with its future implementation hidden behind a thick, dark wall,” says ESA’s Paolo Ferri, head of mission operations.

“This mission has opened a ‘door’ in this wall. The road to achieving a future mission that will detect gravitational waves is still very long, but we can see it and we can now start planning our long journey to reach it.”

http://m.esa.int/Our_Activities/Operations/LISA_Pathfinder_bake_rattle_and_roll

http://m.esa.int/spaceinvideos/Videos/2015/11/Inside_LISA_Pathfinder_with_narration

Offline FutureSpaceTourist

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Re: ESA - LISA Pathfinder updates
« Reply #65 on: 07/14/2017 08:42 AM »
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Today, teams will dump & wipe accumulated hardware test data frm onboard memory - make room for end-of-mission commands #eom #LISAPathfinder

https://twitter.com/esaoperations/status/885766590381404160

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Later, #LISAPathfinder will be commanded to spin up - to further understand its behaviour when manoeuvring #LISAPathfinder

https://twitter.com/esaoperations/status/885766690730061824

Offline eeergo

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Re: ESA - LISA Pathfinder updates
« Reply #66 on: 07/14/2017 02:28 PM »
Quote from: ESAOperations
Update from LISAPathfinder Operations Manager Ian Harrison at ESOC: Today's in-orbit spin-up test postponed. There has been an increase in solar activity, so there's a last-min request to resume LISAPathfinder 'science mode' & measure charge build-up on the test masses. The team are also repeating the low-pressure test on the Cold Gas Thruster system down to 0.2bar. Busy final days! LISAPathfinder proving to be a valuable mission right to the end! Last command 20:00CEST 18.07


https://twitter.com/esaoperations/status/885847575487762433


Related to this, from SpaceWeather.com:


Quote from: http://www.spaceweather.com/archive.php?view=1&day=14&month=07&year=2017
After days of suspenseful quiet, huge sunspot AR2665 finally erupted on July 14th (0209 UT), producing a powerful and long-lasting M2-class solar flare. Extreme ultraviolet telescopes onboard NASA's Solar Dynamics Observatory recorded the blast. Remarkably, the explosion persisted for more than two hours, producing a sustained fusillade of X-rays and energetic protons that ionized the upper layers of Earth's atmosphere. Shortwave radio blackouts were subsequently observed over the Pacific Ocean and especially around the Arctic Circle. Of even greater interest is the coronal mass ejection (CME). The explosion hurled a bright CME away from the blast site, and it appears to be heading for Earth. This expanding cloud will likely reach our planet on July 16th, possibly sparking geomagnetic storms and high-latitude auroras when it arrives.
« Last Edit: 07/14/2017 02:31 PM by eeergo »
-DaviD-

Offline FutureSpaceTourist

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Re: ESA - LISA Pathfinder updates
« Reply #67 on: 07/18/2017 11:03 AM »
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ESA Operations‏ Verified account @esaoperations 2m2 minutes ago

#LISAPathfinder last command transmitted today ~20:00CEST - follow via Facebook live starting 19:45CEST https://www.facebook.com/EuropeanSpaceAgency/

https://twitter.com/esaoperations/status/887265703509848068

19:45 CEST is 17:45 UTC
« Last Edit: 07/18/2017 11:03 AM by FutureSpaceTourist »

Offline FutureSpaceTourist

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Re: ESA - LISA Pathfinder updates
« Reply #68 on: 07/18/2017 12:24 PM »


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Published on 18 Jul 2017

The LISA Pathfinder mission ends on 18 July 2017 after a successful demonstration of the technology needed to detect gravitational waves in space. These vibrations in spacetime, first predicted by Einstein over a hundred years ago, are produced by huge astronomical events - such as two black holes colliding - and will allow scientists to open new windows into our universe.

The success of the LISA Pathfinder mission has paved the way for the newly selected LISA mission which, when built and launched, will detect gravitational waves from objects up to a million times larger than our Sun.

The film features interview soundbites from Dr Paul McNamara, LISA Pathfinder Project Scientist, at the European Space Agency’s European Technology and Science facility (ESTEC) in The Netherlands.

Offline FutureSpaceTourist

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Re: ESA - LISA Pathfinder updates
« Reply #69 on: 07/18/2017 02:47 PM »
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ESA Operations‏ Verified account @esaoperations 9m9 minutes ago

We have #AOS! #LISAPathfinder controllers established contact with their craft for the last time just after 16:00CEST

https://twitter.com/esaoperations/status/887320633343868929

Offline eeergo

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Re: ESA - LISA Pathfinder updates
« Reply #70 on: 07/18/2017 03:10 PM »
https://twitter.com/esaoperations/status/887325525739536384

Quote from: esaoperations
Update from the Main Control Room: A-chain of #LISAPathfinder's redundant on-board systems now OFF & craft is flying on its B-chain.
-DaviD-

Online Chris Bergin

Re: ESA - LISA Pathfinder updates
« Reply #71 on: 07/18/2017 05:59 PM »
And that's the end....


Online catdlr

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Re: ESA - LISA Pathfinder updates
« Reply #73 on: 08/18/2017 03:44 AM »
LISA Pathfinder switch off: Mission summary and beyond

European Space Agency, ESA
Published on Aug 17, 2017


Following 16 months of scientific effort, LISA Pathfinder completed its main mission on 30 June 2017, having demonstrated the technology needed to operate ESA’s future LISA space observatory to study gravitational waves – ripples in space-time predicted by Albert Einstein.

On 18 July, the spacecraft was shut down after being placed in a safe disposal orbit. The final command was sent from ESOC, ESA's European Space Operations Centre, at 19:57 CEST that evening.

That day, scientists, mission controllers, and the mission's management team gathered at ESOC, Darmstadt, Germany, for a presentation on the successes of the mission prior to the shut-down. This video was recorded between 16:00-18:00 CEST, and includes highlight presentations on the mission's achievements.

Speakers:
- Rolf Densing, ESA Director of Operations
- Andreas Rudolph, ESA Head of Astronomy Missions Division
- Ian Harrison, ESA Spacecraft Operations Manager
- Paul McNamara, ESA LISA Pathfinder Project Scientist,
- Prof. Stefano Vitale, Principle Investigator for the LISA Pathfinder Mission, University of Trento
- Phil Barela, NASA/JPL project manager for LISA Pathfinder Disturbance Reduction System
- Colleen Marrese-Reading, JPL/Caltech
- Prof. Karsten Danzmann, Director at the Max-Planck Institute for Gravitational Physics, LISA Pathfinder Co-Principle Investigator

More about LISA Pathfinder:
http://sci.esa.int/lisa-pathfinder/

https://www.youtube.com/watch?v=A8qbgJJUXac?t=001

Tony De La Rosa

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