Search NASA⌕ Search

SEARCH · Search NASA

Results for “LISA, Space Lasers”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS2010

LISA and LISA Pathfinder: Gravitational Wave Observation in Space

The Laser Interferometer Space Antenna (LISA) is a planned NASA-ESA gravitational wave observatory in the frequency range of 0.1 mHz--100 mHz. This observation band is inaccessible to ground-based detectors due to fluctuations in the Earth gravitational field. Gravitational wave sources for LISA include galactic binaries, mergers of supermassive black-hole binaries, extreme-mass-ratio inspirals, and cosmology backgrounds and bursts. LISA is a constellation of three spacecraft separated by 5 million km in an equilateral triangle, whose center follows the Earth in a heliocentric orbit with an orbital phase offset of 20 degrees. Challenging technology is required to ensure pure geodetic trajectories of the six onboard test masses, whose distance fluctuations will be measured by interspacecraft laser interferometers with picometer accuracy. LISA Pathfinder is an ESA-launched technology demonstration mission of key LISA subsystems such as spacecraft control with micronewton thrusters, test mass drag-free control, and precision laser interferometry between free-flying test masses. Ground testing of hardware of the Gravitational Reference Sensor and Optical Metrology subsystems of LISA Pathfinder is currently ongoing. A detailed description of the two missions and an overview of current investigations conducted by the community will be discussed. The current status in development and implementation of LISA Pathfinder pre-flight systems and latest results of the ongoing ground testing efforts will also be presented.

Guzman, Felipe↗
NASA NTRS2006

Engineering the LISA Project: Systems Engineering Challenges

The Laser Interferometer Space Antenna (LISA) is a joint NASA/ESA mission to detect and measure gravitational waves with periods from 1 s to 10000 s. The systems engineering challenges of developing a giant interferometer, 5 million kilometers on a side, an: numerous. Some of the key challenges are presented in this paper. The organizational challenges imposed by sharing the engineering function between three centers (ESA ESTEC, NASA GSFC, and JPL) across nine time zones are addressed. The issues and approaches to allocation of the acceleration noise and measurement sensitivity budget terms across a traditionally decomposed system are discussed. Additionally, using LISA to detect gravitational waves for the first time presents significant data analysis challenges, many of which drive the project system design. The approach to understanding the implications of science data analysis on the system is also addressed.

systems engineering↗
NASA NTRS2010

Preliminary LISA Telescope Spacer Design

The Laser Interferometric Space Antenna (LISA) mission observes gravitational waves by measuring the separations between freely floating proof masses located 5 million kilometers apart with an accuracy of approximately 10 picometers. The separations are measured interferometrically. The telescope is an afocal Cassegrain style design with a magnification of 80x. The entrance pupil has a 40 cm diameter and will either be centered on-axis or de-centered off-axis to avoid obscurations. Its two main purposes are to transform the small diameter beam used on the optical bench to a diffraction limited collimated beam to efficiently transfer the metrology laser between spacecraft, and to receive the incoming light from the far spacecraft. It transmits and receives simultaneously. The basic optical design and requirements are well understood for a conventional telescope design for imaging applications, but the LISA design is complicated by the additional requirement that the total optical path through the telescope must remain stable at the picometer level over the measurement band during the mission to meet the measurement accuracy. This poster describes the requirements for the telescope and the preliminary work that has been done to understand the materials and mechanical issues associated with the design of a passive metering structure to support the telescope and to maintain the spacing between the primary and secondary mirrors in the LISA on-orbit environment. This includes the requirements flowdown from the science goals, thermal modeling of the spacecraft and telescope to determine the expected temperature distribution,layout options for the telescope including an on- and off-axis design, and plans for fabrication and testing.

Livas, J.↗
NASA NTRS1999

The LISA Mission Design

The proposed Laser Interferometer Space Antenna (LISA) is designed to observe gravitational radiation from galactic binaries and massive black holes in other galaxies. LISA will observe waves in the frequency range 0.1 mHz to 1 Hz, which can never be observed on Earth due to background noise. The three LISA spacecraft will be located at the vertices of an equilateral triangle with side length 5 million km. The orbits are chosen so that the triangle formation trails the Earth by 20 degrees. Each spacecraft will contain two independent instruments containing a proof mass, laser and 30 cm diameter telescope for the transmission and reception of laser signals. Two independent Michelson interferometers will be formed, allowing both polarizations of gravitational waves to be detected. The observed signals will yield unique information about the formation of massive black holes and the nature of gravity in the high-field limit.

Folkner, W. M.↗
NASA NTRS2002

LISA Telescope Sensitivity Analysis

The Laser Interferometer Space Antenna (LISA) for the detection of Gravitational Waves is a very long baseline interferometer which will measure the changes in the distance of a five million kilometer arm to picometer accuracies. As with any optical system, even one with such very large separations between the transmitting and receiving, telescopes, a sensitivity analysis should be performed to see how, in this case, the far field phase varies when the telescope parameters change as a result of small temperature changes.

Waluschka, Eugene↗
NASA NTRS2011

LISA: Opening New Horizons

The Laser Interferometer Space Antenna (LISA) is a space-borne observatory that will open the low frequency (approx.0.1-100 mHz) gravitational wave window on the universe. LISA will observe a rich variety of gravitational wave sources, including mergers of massive black holes, captures of stellar black holes by massive black holes in the centers of galaxies, and compact Galactic binaries. These sources are generally long-lived, providing unprecedented opportunities for multi-messenger astronomy in the transient sky. This talk will present an overview of these scientific arenas, highlighting how LISA will enable stunning discoveries in origins, understanding the cosmic order, and the frontiers of knowledge.

Centrella, Joan M.↗
NASA NTRS2014

Gravitational-wave Mission Study

In November 2013, ESA selected the science theme, the "Gravitational Universe," for its third large mission opportunity, known as L3, under its Cosmic Vision Programme. The planned launch date is 2034. ESA is considering a 20% participation by an international partner, and NASA's Astrophysics Division has indicated an interest in participating. We have studied the design consequences of a NASA contribution, evaluated the science benefits and identified the technology requirements for hardware that could be delivered by NASA. The European community proposed a strawman mission concept, called eLISA, having two measurement arms, derived from the well studied LISA (Laser Interferometer Space Antenna) concept. The US community is promoting a mission concept known as SGO Mid (Space-based Gravitational-wave Observatory Mid-sized), a three arm LISA-like concept. If NASA were to partner with ESA, the eLISA concept could be transformed to SGO Mid by the addition of a third arm, augmenting science, reducing risk and reducing non-recurring engineering costs. The characteristics of the mission concepts and the relative science performance of eLISA, SGO Mid and LISA are described. Note that all results are based on models, methods and assumptions used in NASA studies

identified the technology requirements↗
NASA NTRS2007

The Mock LISA Data Challenges: History, Status, Prospects

This slide presentation reviews the importance for the Mock LISA Data Challenges (MLDC). Laser Interferometer Space Antenna (LISA) is a gravitational wave (GW) observatory that will return data such that data analysis is integral to the measurement concept. Further rationale of the MLDC are to kickstart the development of a LISA data-analysis computational infrastructure, and to encourage, track, and compare progress in LISA data-analysis development in the open community. The MLDCs is a coordinated, voluntary effort in GW community, that will periodically issue datasets with synthetic noise and GW signals from sources of undisclosed parameters; increasing difficulty. The challenge participants return parameter estimates and descriptions of search methods. Some of the challenges and the resultant entries are reviewed. The aim is to show that LISA data analysis is possible, and to develop new techniques, using multiple international teams for the development of LISA core analysis tools

data analysis↗
NASA NTRS2017

Bayesian Treatment of Prospective LISA Parameter Estimation for Massive Black Hole Mergers

A full understanding of LISA (Laser Interferometer Space Antenna)'s science capability will require accurate models of incident waveform signals and the instrumental response. While Fisher matrix analysis is useful for some estimates, a full Bayesian treatment is needed for important cases at the limit of LISA's capability. We will apply fast analysis algorithms enabling accurate treatment with EOB (effective-one-body) waveforms and the full-featured LISA response to study the significance of higher spherical harmonics and mergers in LISA analysis.

Baker, John G.↗
NASA NTRS2003

LISA Optics Model: Early Results

The Laser Interferometer Space Antenna (LISA) optics model is used to generate a synthetic data stream in the absence of gravitational waves. The simulation has the spacecraft in moving in their respective Keplerian orbits. The pointing of the spacecraft and station keeping about the proof masses is accomplished using a control scheme, which minimizes the disturbance on the proof masses in the sensitive direction. The resulting data stream gives an indication of the magnitude of instrumental noise due to pointing jitter and motions of the spacecraft with respect to the proof masses. Computational details are presented and the results discussed.

Waluschka, Eugene↗
NASA NTRS2003

LISA Optics and Orbital Motions

The Laser Interferometer Space Antenna (LISA) telescopes must be able to send to and receive light from the other two distant spacecraft. The angle between the distant spacecraft will vary by about one degree in the course of a year. In addition the send and receive directions, for any one telescope, will also vary because of changes in distance, relative velocities of the spacecraft and the flight time of the light. All of these (angular) motions place requirements on the telescope pointing mechanism and the compensating proof mass motions. In this paper we will present the magnitudes of these angular motions, within the context of Keplerian orbits, and the resulting image motions on the detectors.

Waluschka, Eugene↗
NASA NTRS2004

LISA Propulsion Module Separation Study

The Laser Interferometer Space Antenna (LISA) mission is a space-borne gravitational wave detector consisting of three spacecraft in heliocentric orbit. Each spacecraft is delivered to it operational orbit by a propulsion module. Because of the strict thermal and mass balancing requirements of LISA, the baseline mission concept requires that the propulsion module separate from the sciencecraft after delivery. The only propulsion system currently baselined for the sciencecraft are micronewton level thrusters, such as FEEP or colloid thrusters, that are used to balance the 30-40 microN of solar radiation pressure and provide the drag-free and attitude control of the spacecraft. Due to these thrusters limited authority, the separation of the propulsion module from the sciencecraft must be well controlled to not induce a large tip-off rotation of the sciencecraft. We present here the results of a design study of the propulsion module separation system that is shown to safely deliver the LISA sciencecraft to its final operational orbit.

Merkowitz, Stephen↗
NASA NTRS2003

LISA technology department at JPL

The Laser Interferometer Space Antenna (LISA) project requires technology developments on many fronts. A physical understanding of the LISA subsystems is a precursor to tacjling the requirements needed to ensure a successful mission. This can only be achieved by developing the concepts in the lab prior to developing the payload. This poster presents updates on laboratory activities intended to prove the feasibility of measuring proof mass back reaction forces of less than 3fN/(square root)Hz at 1 mHz; the sensing of the proof mass position with in 2 nm/(square root)above the 3 mHz; and the resolution and accuracy of the phase-meter to better than 10 pm/(square root)Hz above the 3 mHz.

optical displacement sensor↗
NASA NTRS2005

Laser frequency stabilization for LISA

The requirement on laser frequency noise in the Laser Interferometer Space Antenna (LISA) depends on the velocity and our knowledge of the position of each spacecraft of the interferometer. Currently it is assumed that the lasers must have a pre-stabilized frequency stability of 30Hz/square root of Hz over LISA'S most sensitive frequency band (3 mHz - 30 mHz). The intrinsic frequency stability of even the most stable com- mercial lasers is several orders of magnitude above this level. Therefore it is necessary to stabilize the laser frequency to an ultra-stable frequency reference which meets the LISA requirements. The baseline frequency reference for the LISA lasers are high finesse optical cavities based on ULE spacers. We measured the stability of two ULE spacer cavities with respect to each other. Our current best results show a noise floor at, or below, 30 Hz/square root of Hz above 3 mHz. In this report we describe the experimental layout of the entire experiment and discuss the limiting noise sources.

Mueller, Guido↗
NASA NTRS2008

Interferometric Testbed for Nanometer Level Stabilization of Environmental Motion Over Long Timescales

We developed an interferometric testbed to stabilize environmental motions over timescales of several hours and a lengthscale of 1m. Typically, thermal and seismic motions on the ground are larger than 1 micron over these scales, affecting the precision of more sensitive measurements. To suppress such motions, we built an active stabilization system composed of interferometric sensors, a hexapod actuator, and a frequency stabilized laser. With this stabilized testbed, environmental motions were suppressed down to nm level. This system will allow us to perform sensitive measurements, such as ground testing of LISA (Laser Interferometer Space Antenna), in the presence of environmental noise.

Numata, Kenji↗
NASA NTRS2011

Phase-Controlled Magnetic Mirror for Wavefront Correction

Typically, light interacts with matter via the electric field and interaction with weakly bound electrons. In a magnetic mirror, a patterned nanowire is fabricated over a metallic layer with a dielectric layer in between. Oscillation of the electrons in the nanowires in response to the magnetic field of incident photons causes a re-emission of photons and operation as a "magnetic mirror." By controlling the index of refraction in the dielectric layer using a local applied voltage, the phase of the emitted radiation can be controlled. This allows electrical modification of the reflected wavefront, resulting in a deformable mirror that can be used for wavefront control. Certain applications require wavefront quality in the few-nanometer regime, which is a major challenge for optical fabrication and alignment of mirrors or lenses. The use of a deformable magnetic mirror allows for a device with no moving parts that can modify the phase of incident light over many spatial scales, potentially with higher resolution than current approaches. Current deformable mirrors modify the incident wavefront by using nano-actuation of a substrate to physically bend the mirror to a desired shape. The purpose of the innovation is to modify the incident wavefront for the purpose of correction of fabrication and alignment-induced wavefront errors at the system level. The advanced degree of precision required for some applications such as gravity wave detection (LISA - Laser Interferometer Space Antenna) or planet finding (FKSI - Fourier-Kelvin Stellar Interferometer) requires wavefront control at the limits of the current state of the art. All the steps required to fabricate a magnetic mirror have been demonstrated. The modification is to apply a bias voltage to the dielectric layer so as to change the index of refraction and modify the phase of the reflected radiation. Light is reflected off the device and collected by a phase-sensing interferometer. The interferometer determines the initial wavefront of the device and fore optics. A wavefront correction is calculated, and voltage profile for each nanowire strip is determined. The voltage is applied, modifying the local index of refraction of the dielectric under the nanowire strip. This modifies the phase of the reflected light to allow wavefront correction.

Hagopian, John↗