LISA Pathfinder scheduled to launch tomorrow, 2015-12-01

LISA Pathfinder -- a technology-demonstrator mission for the proposed
eLISA space-based gravitational-wave detector -- is scheduled to launch
tomorrow (1 December 2015), at 11:15pm US-Eastern time.

For more on eLISA and LISA Pathfinder see
https://en.wikipedia.org/wiki/Evolve..._Space_Antenna
https://en.wikipedia.org/wiki/LISA_Pathfinder

Quoting from a recent E-mail from Ann Hornschemeier at NASA,

LISA Pathfinder is scheduled to launch -tomorrow- December 1st at
11:15PM Eastern time.

** For live streaming of the launch, there are two options:

* Ariane Space: http://www.arianespace.tv/
* ESA TV:
http://www.esa.int/esatv/Transmissio..._Vega_V06_Live

*** For more information on LISA Pathfinder launch events and activities:

There is a new website (lisapathfinder.org http://lisapathfinder.org/)
provided by the eLISA Consortium

*** For more information on LISA Pathfinder in general:

"Official" ESA website:

ESA Science Site: http://www.cosmos.esa.int/web/lisa-pathfinder


Twitter: @ESA_LPF, @esascience, @arianespace, #lisapathfinder, #VV06
Facebook: https://www.facebook.com/lpf.lisapathfinder/about

ciao,

--
-- "Jonathan Thornburg [remove -animal to reply]"
Dept of Astronomy & IUCSS, Indiana University, Bloomington, Indiana, USA
"There was of course no way of knowing whether you were being watched
at any given moment. How often, or on what system, the Thought Police
plugged in on any individual wire was guesswork. It was even conceivable
that they watched everybody all the time." -- George Orwell, "1984"

On 11/30/15 2:00 PM, Jonathan Thornburg [remove -animal to reply] wrote:
LISA Pathfinder -- a technology-demonstrator mission for the proposed
eLISA space-based gravitational-wave detector -- is scheduled to launch
tomorrow (1 December 2015), at 11:15pm US-Eastern time. 'Delayed till 3 December'

It will be interesting to see if LISA Pathfinder
will observe 10^-4 to 10^-5 Hz frequencies
as observed by
Gravity Probe B gyros.

RDS

[[Mod. note --
1. LISA Pathfinder is an engineering test mission containing an
interferometer with a ~50cm armlength, not a gravitational-wave
observatory with a multi-million-km armlength. Because
gravitational-wave sensitivity is roughly proportional to
armlength, LISA Pathfinder won't have any scientifically-interesting
gravitational-wave sensitivity. Rather its purpose is to test
and demonstrate various engineering subsystems (e.g., very-low-noise
interferometers, interferometric measurement with picometer sensitivity,
vibration control, drag-free control systems, microNewton thrusters,
etc etc) which can then be applied to the eLISA mission (or even a
resurrected LISA if someone comes up with a spare 0.5e9 or so
dollars/Euros) mission.

2. LISA had peak sensitivity at frequencies of a few mHz; eLISA is
currently planned to have peak sensitivity at slightly frequencies,
maybe around 10 mHz. eLISA won't be very sensitive at the 10-100
microHz frequencies you mention.

3. Gravity Probe B didn't observe gravitational waves at any frequency.
Rather it (using those super-low-noise gyros, and various other
fancy technologies) observed
(a) geodetic precession due to the satellite orbiting the Earth, and
(b) Lenz-Thirring frame-dragging due to the Earth being spinning
-- jt]]

On 12/2/15 3:09 AM, Richard D. Saam wrote:
On 11/30/15 2:00 PM, Jonathan Thornburg [remove -animal to reply] wrote:
LISA Pathfinder -- a technology-demonstrator mission for the proposed
eLISA space-based gravitational-wave detector -- is scheduled to launch
tomorrow (1 December 2015), at 11:15pm US-Eastern time. 'Delayed till 3 December'

It will be interesting to see if LISA Pathfinder
will observe 10^-4 to 10^-5 Hz frequencies
as observed by
Gravity Probe B gyros.

RDS

[[Mod. note --
1. LISA Pathfinder is an engineering test mission containing an
interferometer with a ~50cm armlength, not a gravitational-wave
observatory with a multi-million-km armlength. Because
gravitational-wave sensitivity is roughly proportional to
armlength, LISA Pathfinder won't have any scientifically-interesting
gravitational-wave sensitivity. Rather its purpose is to test
and demonstrate various engineering subsystems (e.g., very-low-noise
interferometers, interferometric measurement with picometer sensitivity,
vibration control, drag-free control systems, microNewton thrusters,
etc etc) which can then be applied to the eLISA mission (or even a
resurrected LISA if someone comes up with a spare 0.5e9 or so
dollars/Euros) mission.

2. LISA had peak sensitivity at frequencies of a few mHz; eLISA is
currently planned to have peak sensitivity at slightly frequencies,
maybe around 10 mHz. eLISA won't be very sensitive at the 10-100
microHz frequencies you mention.

3. Gravity Probe B didn't observe gravitational waves at any frequency.
Rather it (using those super-low-noise gyros, and various other
fancy technologies) observed
(a) geodetic precession due to the satellite orbiting the Earth, and
(b) Lenz-Thirring frame-dragging due to the Earth being spinning
-- jt]]


Gravity Probe B did establish (a) and (b)
but in the process its super-low-noise gyros
did observe anomalous 10-100 microHz frequencies
having a particular harmonic pattern.
(in tune with a universe source?)

Alex Silbergleit, John Conklin and the Polhode/Trapped Flux Mapping Task
Team, Hansen Experimental Physics Laboratory(HEPL) Seminar, Polhode
Motion, Trapped Flux, and the GP-B Science Data Analysis, July 8, 2009,
Stanford University.

The super-low-noise gyros incorporated niobium superconducting material
introducing an unknown/unanticipated contributor to the experiment.
The anomalous 10-100 microHz frequencies were brushed away
with subsequent computer finesse.
ESA graphics indicate some 10-100 microHz frequency sensitivity.
Is it enough sensitivity to replicate
those anomalous Gravity Probe B 10-100 microHz frequencies?
RDS


[[Mod. note -- I think it would be very hard to make a solid case
that a substantial part of Gravity Probe B's noise was due to
gravitational waves (as opposed to various other noise sources within
the Gravity Probe B spacecraft).

That said, the full eLISA mission should have fairly good sensitivity
at 10-100 microHz (probably limited by "confusion noise" from the large
number of unresolved close-white-dwarf binaries in our galaxy). I don't
think LISA Pathfinder will have any scientifically useful gravitational-
-wave sensitivity.
-- jt]]

On Thursday, December 3, 2015 at 2:02:32 AM UTC-5, Richard D. Saam wrote:
[[Mod. note -- 70 excessively-quoted lines snipped here. -- jt]]

[[Mod. note -- I think it would be very hard to make a solid case
that a substantial part of Gravity Probe B's noise was due to
gravitational waves (as opposed to various other noise sources within
the Gravity Probe B spacecraft).

That said, the full eLISA mission should have fairly good sensitivity
at 10-100 microHz (probably limited by "confusion noise" from the large
number of unresolved close-white-dwarf binaries in our galaxy). I don't
think LISA Pathfinder will have any scientifically useful gravitational-
-wave sensitivity.
-- jt]]

If memory servers liquid helium splashing around was another variable
that had to be massaged out of the B probe data. Not sure how liquid
helium could splash around without a gravity gradient but apparently
it did. As helium depleted the frequency changed which was a red
flag that this was a liquid helium resonate splashing problem.

A 1 meter length with a positive charge on one side and a negative
charge on the other. A gravity wave would change the distance between
the negative and positive charges. Theoretically this should translate
a gravity wave into an electromagnetic wave. However this would be
limited to gravity waves in the 200 MHz range with only a 1 meter
length. There is theory and there are measurements made. The common
AM radio with a sensitivity of 10 u volts , 10e-6 V , can receive
EM waves in the 1 MHz range with a ferrite antenna that is less
than .01 percent of the EM wave length of 1 MHz. 1 MHz wave length
is a few city blocks long but the ferrite antenna is only 2 or 3
inches long. It is possible we already have the technology , radio
, to measure gravity waves in a more efficient way if a gravity
wave could be translated into a EM wave such as the example of a
positive and negative charge placed 1 meter apart in the path of a
gravity wave.


[[Mod. note -- Unfortunately, detecting gravitational waves is MUCH
harder than detecting radio waves.
[It's best to refer to "gravitational waves", not
"gravity waves", because the latter term already has
a well-established and quite different meaning,
referring to (e.g.) the usual waves one sees on the
surface of the Earth's ocean.]
Roughly speaking, detecting gravitational waves is about as hard as
detecting radio waves would be if the only materials we had available
from which to construct our radio antenna were different types of wood.

More quantitatively, we expect any gravitational waves here on Earth
to be VERY weak, corresponding to a fractional change in the distance
between those two test bodies of much less than 1 part in 10^20.
That means we (a) a VERY sensitive measurement of the distance between
the test bodies, and (b) a VERY low level of background noise. (b)
in turn means that we want our test bodies to be electrically neutral
and non-magnetic, so as to minimize the effects of any stray
electromagnetic fields.
-- jt]]

On 1/16/16 9:40 PM, John Heath wrote:
On Thursday, December 3, 2015 at 2:02:32 AM UTC-5, Richard D. Saam wrote:
[[Mod. note -- 70 excessively-quoted lines snipped here. -- jt]]

[[Mod. note -- I think it would be very hard to make a solid case
that a substantial part of Gravity Probe B's noise was due to
gravitational waves (as opposed to various other noise sources within
the Gravity Probe B spacecraft).

That said, the full eLISA mission should have fairly good sensitivity
at 10-100 microHz (probably limited by "confusion noise" from the large
number of unresolved close-white-dwarf binaries in our galaxy). I don't
think LISA Pathfinder will have any scientifically useful gravitational-
-wave sensitivity.
-- jt]]

If memory servers liquid helium splashing around was another variable
that had to be massaged out of the B probe data. Not sure how liquid
helium could splash around without a gravity gradient but apparently
it did. As helium depleted the frequency changed which was a red
flag that this was a liquid helium resonate splashing problem.


Some type of Gravity Probe B splashing is evident,
but was it helium
or the actual gyro niobium superconductor 'fluid' medium
at an estimated density of 8x10^-6 g/cc?
But the question remains:
what oscillating gravitational gradient could cause such?

Alex Silbergleit, John Conklin
and the Polhode/Trapped Flux Mapping Task
Team, Hansen Experimental Physics Laboratory(HEPL) Seminar,
Polhode Motion, Trapped Flux,
and the GP-B Science Data Analysis, July 8, 2009,
Stanford University.
https://einstein.stanford.edu/RESOUR...ilbergleit.pdf

1. Asymptotic Polhode Period and Dissipation Time
(and calculated harmonics
after equilibrating Dissipation Time 'months')

/ Asymptotic Asymptotic Asymptotic Asymptotic
/ Polhode Polhode Polhode Polhode
/ Period Frequency Harmonic Harmonic
/ (hours) (Hz) Deviation

Gyro 1 0.867 3.20E-04 9 1.05
Gryo 3 1.529 1.82E-04 5 1.08
Gyro 2 2.581 1.08E-04 3 1.06
Gyro 4 4.137 6.71E-05 2 0.99
Universe? 8.22 3.38E-05 1 1.00

The LISA-pathfinder free fall test masses described at

http://sci.esa.int/lisa-pathfinder/5...sa-pathfinder/

are sensitive to 10^-3 to 10^-1 Hz
and may detect the Gravity Probe B observed Universe?
oscillating gravitational gradient at high (10) harmonics.

What is the actual mass(g) of the test mass cubes?

ESA is not looking for this anomalous effect
on this LISA test run
but its experimental appearance could be evident.

Richard D Saam