The usual structural and thermal analysis of the spacecraft has therefore been extended to include gravitational effects as well to ensure that the requirements on gravity gradient at the position of the test masses is fully met. In addition, the payload controls the position of the spacecraft during science operations, rendering the spacecraft effectively a part of the instrument. The importance of the co-design and the co-operation of spacecraft and payload is captured in the term […]
LISA’s distance measuring system is a continuous interferometric laser ranging scheme, similar to systems used for radar-tracking of spacecraft. But for LISA, the direct reflection of laser light, such as in a normal Michelson interferometer, is not feasible due to the large distance of million km between the spacecraft: Diffraction expands the laser beam so much that for each Watt of laserpower sent, only about 250 pW are received. Direct reflection would thus result in an attenuation factor of about 6.25 x 10-20, yielding about one photon in every three […]
It’s an acronym: LISA stands for “Laser Interferometer Space […]
Key components of LISA´s data analysis are the ability of creating high-fidelity waveforms for gravitational wave sources, having a well-understood signal simulator for the mission, and being able to extract the source parameters from the simulated signals. In so-called Mock LISA Data Challenges (MLDC) scientists already demonstrated the feasibility of LISA data […]
In strong interaction with the Data Analysis Groups of the LISA Consortium, the DPC will implement, execute and control the data analysis pipelines and deliver the scientific products (such as catalogues of identified gravitational waves) to the consortium. To do so, it’s main focus will be on developing tools to support: software development, test and validation; pipeline integration and deployment on computing infrastructures; data management, tracing and archiving; simulation […]
LDCs are based on blind challenges of increasing complexity – from a few sources in the first challenge to the full combination of all likely sources in the data stream in the most recent fourth challenge. Scientific research groups from all over the world developed, tested and implemented a wide variety of techniques. As a result a proof-of-concept for LISA data analysis is strongly tested and ready to […]
A data pipeline is a set of actions that ingest raw data from disparate sources and move the data to a destination for storage and analysis. A pipeline also may include filtering and features that provide resiliency against failure. There are essentially three major types of pipelines along the transportation route: gathering systems, transmission systems, and distribution […]
Gravitational waves are ripples in the fabric of space-time generated by some of the most powerful astrophysical events – such as exploding stars and collisions of two black holes at the centres of galaxies. Gravitational waves travel at the speed of light through the universe, unhindered by intervening mass – to gravitational waves the universe is transparent. That is why gravitational waves are the cosmic messengers that allow us to explore the so far dark side of the […]
Ariane 6 and/or Vega-C (co-developed by ArianeGroup and Avio) are possible […]
The test masses are 46 mm cubes, made from a dense non-magnetic Au-Pt alloy and shielded by the Gravitational Reference Sensor (GRS). The GRS core is a housing of electrodes, at several mm separation from the test mass, used for precision capacitive sensing and electrostatic force actuation in all non-interferometric degrees of freedom. The GRS also includes fibers for UV light injection for photoeletric discharge of the test mass and a caging mechanism for protecting the test mass during launch and then releasing it in orbit. The GRS technology is a direct heritage from LISA […]
LISA is led by the European Space Agency, with NASA as a partner. In Europe, the Max Planck Albert Einstein Institute is the lead for the LISA Consortium. In the US, NASA Goddard is the lead center, with Marshall and JPL also contributing. On both continents, scientists at many (tens of) institutions are contributing technology and observational […]
LISA´s payload consists of two identical units on each spacecraft. Each unit contains a Gravitational Reference Sensor (GRS) with an embedded free-falling test mass that acts both as end point of the optical length measurement and as geodesic reference test particle. A telescope transmits the laser light along the arm and also receives the weak light (few hundred pico-Watts!) from the other end. Laser interferometry is performed on an optical bench in between the telescope and the […]