scholarly journals The free-fall mode experiment on LISA Pathfinder: first results

2017 ◽  
Vol 840 ◽  
pp. 012005 ◽  
Author(s):  
Roberta Giusteri ◽  
Keyword(s):  
Free Fall ◽  
Lisa Pathfinder ◽  
First Results

LISA Pathfinder first results

2017 ◽  
Vol 26 (05) ◽  
pp. 1741023 ◽  
Author(s):  
D. Vetrugno ◽  
Keyword(s):  
Gravitational Wave ◽  
Laser Interferometer ◽  
Free Fall ◽  
Space Antenna ◽  
Essential Ingredient ◽  
Lisa Pathfinder ◽  
Laser Interferometer Space Antenna ◽  
The Future ◽  
First Results

LISA Pathfinder (LPF) is an in-flight technological demonstrator designed and launched to prove the feasibility of sub-femto-[Formula: see text] free fall of kilo-sized test masses (TM), an essential ingredient for the future gravitational wave observatory from space. Half a year after launch, the first results are available and show an incredibly well-performing instrument. The results represent a first and important step towards the long awaited construction and launch of LISA, the Laser Interferometer Space Antenna.

scholarly journals Beyond the Required LISA Free-Fall Performance: New LISA Pathfinder Results down to 20  μHz

2018 ◽  
Vol 120 (6) ◽  
Author(s):  
M. Armano ◽  
H. Audley ◽  
J. Baird ◽  
P. Binetruy ◽  
M. Born ◽  
...  
Keyword(s):  
Free Fall ◽  
Lisa Pathfinder

Measuring fN force variations in the presence of constant nN forces: a torsion pendulum ground test of the LISA Pathfinder free-fall mode

2018 ◽  
Vol 35 (3) ◽  
pp. 035017 ◽  
Author(s):  
G Russano ◽  
A Cavalleri ◽  
A Cesarini ◽  
R Dolesi ◽  
V Ferroni ◽  
...  
Keyword(s):  
Free Fall ◽  
Torsion Pendulum ◽  
Lisa Pathfinder ◽  
Ground Test

THE LISA PATHFINDER MISSION

2013 ◽  
Vol 22 (01) ◽  
pp. 1341001 ◽  
Author(s):  
PAUL W. McNAMARA
Keyword(s):  
Gravitational Wave ◽  
Inertial Sensors ◽  
European Space Agency ◽  
Low Frequency ◽  
Free Fall ◽  
Flight Test ◽  
Measurement Technology ◽  
Gravitational Wave Detection ◽  
Wave Detection ◽  
Lisa Pathfinder

Laser Interferometer Space Antenna (LISA) Pathfinder (formerly known as SMART-2) is a European Space Agency mission designed to pave the way for the joint ESA/NASA LISA mission by testing in flight the critical technologies required for space borne gravitational wave detection; it will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy. This is achieved through technology comprising inertial sensors, high precision laser metrology, drag-free control and an ultra precise micro-Newton propulsion system. LISA Pathfinder (LPF) essentially mimics one arm of space-borne gravitational wave detectors by shrinking the million kilometer scale armlengths down to a few tens of centimeters, giving up the sensitivity to gravitational waves, but keeping the measurement technology. The scientific objective of the LPF mission consists then of the first in-flight test of low frequency gravitational wave detection metrology.

scholarly journals Temperature stability in the sub-milliHertz band with LISA Pathfinder

2019 ◽  
Vol 486 (3) ◽  
pp. 3368-3379
Author(s):  
M Armano ◽  
H Audley ◽  
J Baird ◽  
P Binetruy ◽  
M Born ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Transfer Functions ◽  
Thermal Environment ◽  
Low Frequency ◽  
Temperature Stability ◽  
Free Fall ◽  
Noise Levels ◽  
Lisa Pathfinder ◽  
Frequency Regime ◽  
Mission Operations

Abstract LISA Pathfinder (LPF) was a technology pioneering mission designed to test key technologies required for gravitational wave detection in space. In the low frequency regime (milliHertz and below), where space-based gravitational wave observatories will operate, temperature fluctuations play a crucial role since they can couple into the interferometric measurement and the test masses’ free-fall accuracy in many ways. A dedicated temperature measurement subsystem, with noise levels in 10 $\mu$K Hz−1/2 down to 1 mHz was part of the diagnostics unit onboard LPF. In this paper we report on the temperature measurements throughout mission operations, characterize the thermal environment, estimate transfer functions between different locations, and report temperature stability (and its time evolution) at frequencies as low as 10 $\mu$Hz, where typically values around 1 K Hz−1/2 were measured.

scholarly journals LISA Pathfinder Performance Confirmed in an Open-Loop Configuration: Results from the Free-Fall Actuation Mode

2019 ◽  
Vol 123 (11) ◽  
Author(s):  
M. Armano ◽  
H. Audley ◽  
J. Baird ◽  
P. Binetruy ◽  
M. Born ◽  
...  
Keyword(s):  
Free Fall ◽  
Open Loop ◽  
Lisa Pathfinder ◽  
Actuation Mode

Discussion of the Oblique Rotator Model Cases Of 108 Aqr and x Serp.

1976 ◽  
Vol 32 ◽  
pp. 577-588
Author(s):  
C. Mégessier ◽  
V. Khokhlova ◽  
T. Ryabchikova
Keyword(s):  
Mathematical Formulation ◽  
The Other ◽  
Rotator Model ◽  
Oblique Rotator ◽  
First Results

My talk will be on the oblique rotator model which was first proposed by Stibbs (1950), and since received success and further developments. I shall present two different attempts at describing a star according to this model and the first results obtained in the framework of a Russian-French collaboration in order to test the precision of the two methods. The aim is to give the best possible representation of the element distributions on the Ap stellar surfaces. The first method is the mathematical formulation proposed by Deutsch (1958-1970) and applied by Deutsch (1958) to HD 125248, by Pyper (1969) to α2CVn and by Mégessier (1975) to 108 Aqr. The other one was proposed by Khokhlova (1974) and used by her group.

Meridional Circulation, Turbulence, and Diffusion Processes in Stars

1976 ◽  
Vol 32 ◽  
pp. 109-116 ◽  
Author(s):  
S. Vauclair
Keyword(s):  
Convection Zone ◽  
Diffusion Processes ◽  
Meridional Circulation ◽  
Diffusion Time ◽  
Work In Progress ◽  
First Results ◽  
Stellar Envelopes ◽  
And Diffusion ◽  
Turbulence And Diffusion ◽  
Hr Diagram

This paper gives the first results of a work in progress, in collaboration with G. Michaud and G. Vauclair. It is a first attempt to compute the effects of meridional circulation and turbulence on diffusion processes in stellar envelopes. Computations have been made for a 2 Mʘstar, which lies in the Am - δ Scuti region of the HR diagram.Let us recall that in Am stars diffusion cannot occur between the two outer convection zones, contrary to what was assumed by Watson (1970, 1971) and Smith (1971), since they are linked by overshooting (Latour, 1972; Toomre et al., 1975). But diffusion may occur at the bottom of the second convection zone. According to Vauclair et al. (1974), the second convection zone, due to He II ionization, disappears after a time equal to the helium diffusion time, and then diffusion may happen at the bottom of the first convection zone, so that the arguments by Watson and Smith are preserved.

Investigation of cluster layers of small netal particles by TEM, SEM, EELS and by photoacoustic spectroscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 250-251
Author(s):  
H. Seiler ◽  
U. Haas ◽  
K.H. Körtje
Keyword(s):  
Bulk Material ◽  
High Vacuum ◽  
Optical Methods ◽  
Metal Particles ◽  
Silver Particles ◽  
Low Loss ◽  
Plasmon Excitation ◽  
First Results ◽  
Diffraction Patterns ◽  
Small Metal Particles

The physical properties of small metal particles reveal an intermediate position between atomic and bulk material. Especially Ag has shown pronounced size effects. We compared silver layers evaporated in high vacuum with cluster layers of small silver particles, evaporated in N2 at a pressure of about 102 Pa. The investigations were performed by electron optical methods (TEM, SEM, EELS) and by Photoacoustic (PA) Spectroscopy (gas-microphone detection).The observation of cluster layers with TEM and high resolution SEM show small silver particles with diameters of about 50 nm (Fig. 1 and Figure 2, respectively). The electron diffraction patterns of homogeneous Ag layers and of cluster layers are similar, whereas the low loss EELS spectra due to plasmon excitation are quite different. Fig. 3 and Figure 4 show first results of EELS spectra of a cluster layer of small silver particles on carbon foil and of a homogeneous Ag layer, respectively.

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