https://www.ligo.caltech.edu/news/ligo20160607
https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.116.231101
Congratulations LISA Pathfinder!
News Release • June 7, 2016
LIGO laboratory congratulates everyone involved with the LISA Pathfinder mission on its successful demonstration of the technology needed to build a space-based gravitational wave observatory. According to LIGO Lab Director David Reitze “The LISA Pathfinder results announced today are a spectacular confirmation that is possible to achieve the measurement precision needed for detecting gravitational waves in space. LISA will explore a completely different region of the gravitational wave spectrum and inform us about supermassive black hole mergers and other astrophysical phenomena inaccessible to LIGO.”
LISA Pathfinder (LPF) is a European Space Agency
mission launched on December 3, 2015 and dedicated to an
end-to-end experimental demonstration of the free fall of
test masses (TMs) at the level required for a future
space-based gravitational wave (GW) observatory, such
as LISA
Following launch and a 50 day cruise phase to its final
orbit around the L1 Lagrange point of the Sun-Earth
system, LISA Pathfinder separated from its propulsion
module. Commissioning of the instrument followed, with
the release of the two TMs into free fall 74 days after launch
in mid-February. The mission began science operations on
March 1, 2016, 89 days after launch, and has been
operating smoothly ever since.
The core instrument of LPF , consists of two quasi-
cubic test masses, of size ð46.000 0.005Þ mm and mass
M ¼ ð1.928 0.001Þ kg, formed from a high-purity gold-
platinum alloy. During science operations, these masses are
in free fall inside a single spacecraft with their centers
separated by a nominal distance of ð376.00 0.05Þ mm
along a line that we take as the x axis (see Fig. 2)
Each TM is contained within an electrode housing
,which serves as an electrostatic shield in addition to a
6 degree-of-freedom sensor and electrostatic force actuator,
with gaps around the mechanically and electrically isolated
TM of 2.9–4 mm on the different axes.