In Largest Science Experiment Ever, Three Spacecraft Will Swap Laser Fire Across 3 Million Miles

Proving or disproving Gravitational Waves will certainly shake up the world of physics. Especially if they are disproved.

I certainly hope they've equipped them to do something after this mission is completed..since it takes millions of dollars just to launch them.

K my figures tell me dark traveles faster then light. God dam I have more. Like a mother fluiffer.

@Soroshi....not sure if the lack of detection will necessarily disprove the existence of Gravitational Waves.
Perhaps they will just say that thier instruments are not accurate enough or not geared to correctly measure them.

"Einstein's general relativity predicts several things, such as gravity's ability to bend time light and the constant speed at which gravity travels."

i believe that should be - gravity's ability to bend light and the constant speed at which light travels. that really ought to be corrected.

"to within 40 millionths of a millionth of a meter"!!

That's extreme. That rounds up to 25 femtometers; roughly the length of 15 protons put together. How they keep the spacecraft in position that well and not skew the results from those distances is beyond me.

But why do I feel that NASA will end up cancelling that project too.

2020? I hope it actually gets done. We will see if NASA can hold to a task that far in the future. So far, they have not done that well.

It would be better if there were a 4th satellite formed in a tetrahedron. that way there would be no necessity to orient the triangle in a proposed direction. whoever designed this experiement was very short sighted.

Are these waves a threat? Is there really any doubt about gravity? It works fine.

This is a big waste of money!

It would be better to wait until some clever student figures out a way to do the same experiment here on earth.

mitcheisenstein's comment shows how poorly this was thought out. The systems savings probably would have help to pay for the 4th satellite.

From somebody who has worked on LISA since 2002:

- LISA is not about proving gravitational waves, but using them to learn unique information about astrophysical sources across the Universe (for instance, see lisa.nasa.gov). By the time LISA is launched, gravitational waves will have been detected already by ground-based observatories. In any case, we know of gravitational-wave sources in the Milky Way from optical observations that WILL be seen by LISA, if it works correctly.

- Millionth millionths of meters are picometers, not femtometers; such a measurement precision is easily achievable on the Earth using interferometry (just as LISA will). The spacecraft are not controlled into formation, but orbit the Sun as they might. It so happens that incoming gravitational waves create oscillations in inter-spacecraft distances that are distinguishable (because they have different frequencies) from the changes due to orbital motions.

- NASA does routinely work on missions that stretch across decades. Think of Cassini, or the Voyagers. If LISA gets full funding now, it will really take all of the next ten year to get it ready. That's space science.

- A tetrahedral LISA would be very cool, but it cannot be maintained with Keplerian orbits. But a triangle is OK. There's no need to orient it, though, since LISA is naturally an omnidirectional detector.

- Last, LISA cannot be done on Earth, because it measures waves at frequencies (between 10^-4 and 10^-2 cycles per second) where Earth-based disturbancies are just too great; and because the gravitational wavelength for these frequencies is commensurate to the 5-million-km armlength.