LISA Pathfinder’s Stunning Success

LISA Pathfinder, a mission led by the European Space Agency (ESA) with contributions from NASA, has successfully tested a key technology needed to build a space-based observatory for detecting gravitational waves. These tiny ripples in the fabric of space, predicted by Albert Einstein a century ago, were first seen last year by the ground-based Laser Interferometer Gravitational-Wave Observatory (LIGO).

Seismic, thermal, and other noise sources limit LIGO to higher-frequency gravitational waves around 100 cycles per second (hertz). But finding signals from more exotic events, such as mergers of supermassive black holes in colliding galaxies, requires the ability to see frequencies at 1 hertz or less, a sensitivity level only possible from space.

A space-based observatory would work by tracking test masses that move only under the influence of gravity. Each spacecraft would gently fly around its test masses without disturbing them, a process called drag-free flight. The primary goal of ESA's LISA Pathfinder mission is to test current technology by flying around an identical pair of 1.8-inch (46 millimeter) cubes made of a gold-platinum alloy, a material chosen for its high density and insensitivity to magnetic fields.

Scientists say the results are nothing short of astonishing. Non-gravitational forces on the cubes were reduced to levels far below the project's original requirements and approach the level of control needed for a full-scale observatory.

The test masses are housed in an experiment called the LISA Technology Package (LTP), which was built by a consortium of European national space agencies and ESA. The LTP uses a high-resolution laser interferometer to determine the positions of the test masses and relays the information to the spacecraft's Drag-Free and Attitude Control System, which then applies minute bursts from microthrusters. In this way, the spacecraft flies in formation with the cubes and isolates them from external forces. The results show that LISA Pathfinder reduced non-gravitational forces on the test masses to a level about 10,000 times smaller than drag-free control technologies used on previous science missions.

LISA Pathfinder also carries a NASA experiment called the ST-7 Disturbance Reduction System which is expected to begin science operations in early July.

LISA Pathfinder was launched on Dec. 3, 2015, and began orbiting a point called Earth-sun L1, roughly 930,000 miles (1.5 million kilometers) 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. The LISA Pathfinder mission is an ESA-led effort to demonstrate technologies for a future gravitational wave observatory in space. NASA Goddard astrophysicist Ira Thorpe, a member of the team, discusses the mission and its spectacular results so far.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

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[Rando_Shyte]

This should have millions of views. Sad that so few people have a passion for physics. I'm a profesional musician but Ive watched literally thousands of space and physics videos and they give my life a lot of joy.

[shmookins]

Amazing. I love the precision of the new equipment and the evolution of that through time.
Go science!

[AntifoulAwl]

Those reassuring little sputnik beeps at the end always complete the video nicely :)

[jourdannoela]

The CNRS research director in France is a member of my family . We discussed this idea in 1995. He was looking for a research topic and I just said, "There are an infinite galaxies, with all the pollution it would be appropriate to explore to see if there is a habitable planet ".
In 2002 I had a little girl named Elisa. NASA has validated the project (!). With the English language, it was impossible ELISA. So it became LISA!
It's fantastic...

[alexandrugheorghe]

Great engineering. Very inspiring! Thank you for sharing.

[harryandruschak]

Thank you for this informative upload :)

[pyrrho]

HOLY SHIT THAT'S BRILLIANT. The satelite will just adjust to always stay around the object in perfect free fall. They will still have to subtract the motion due to uneven gravity FROM the earth.

[livinggratefully]

Anyone know of up to date info on how this is going?

[PTNLemay]

Will the prototype be able to contribute in the final mission observations?

[LowLightVideos]

I guess that there was a reason not to use the Meissner state of Mercury as a variable sized Test Mass instead of a fixed sized cube made of a Gold-Platinum alloy.

[PavloPravdiukov]

2:51 Todd Howard joined LISA Pathfinder project

[Sarruji]

I think this may lead to the knowledge and breakthroughs that are needed to understand "FTLT"

[NickiCorset]

the thumbnail looks like its crashing into the earth, god save us

[Haru]

This is really cool. I hope gravity waves and research like it aren't rolled out in congress as one representative's (Republican's) idea of 'wasteful spending.'

[paublusamericanus]

it is very inspiring, very, but no enchilada. as in the whole enchilada, that is actually using a space based system. I personally feel this will be second to very good baseline studies of neutron star spins. that will create resolutions not available with mere satellites, but will probably have its own pitfalls, and extravagances with each process. that is how science progresses. not how we think, but how reality proceeds. our mental models can be faulty, of everything. and the way the political situation is decaying, it may be that james webb doesn't reach trojan.

[duncanbates]

Exciting times for astronomy and cosmology, an entirely new way to probe the Universe. LIGO is doing well but I can't wait for eLISA, planned for 2034 dammit.
We will learn a lot about the cosmos from this, maybe even get hints on how to reconcile gravity with QM?

[coreybauer]

First one to make a way to communicate with another universe wins a surprise party 😁😁😁

[oracleofottawa]

If LIGO works so well, why would you need LISA PATHFINDER?

[KuyaManzano]

Is social media the key to success nowadays?

[Potaville]

NA$A I have a question. Why were mine and many others comments removed from many of your videos? As an American Tax payer, I pay for all that you do along with my fellow Americans. I love to read the comments about these videos but have been seeing them all being erased! Why? Do the American tax payers not have the right to comment without have their comments erased? Please stop this ridiculous activity at once. I noticed that many, many American tax payers do not believe all that NA$A claims to be doing in $pace! In fact, I was very stunned to see that many American Tax payers do not believe anything has ever been to $pace as of late! This is extremely interesting to me to read in these comments on these videos. Are the American tax payers not allowed to question if NA$A is telling the truth about what they are claiming to do in $pace or are we to just Believe everything we are told like good "Sheeple" ???? What is the deal with erasing and disabling comments?