LAGRANGE: LAser GRavitational-wave ANtenna at GEo-lunar Lagrange points

NASA is working with the science community to develop new gravitational-wave mission concepts satisfying some or all of the scientific objectives of LISA. Such scenarios might include one or more space-based observatories. These scenarios will be presented to the National Research Council’s Space Studies Board Committee on Astronomy and Astrophysics (CAA) for consideration. Recommendations from the CAA will subsequently be used to guide detailed development of scientific, technical, and cost information for future US gravitational-wave missions. Data from these concept studies will also be used to assess future technology needs for the Astrophysics Division. See Physics of the Cosmos for more info, including the presentation about LAGRANGE.

LAGRANGE is a space gravitational wave observatory design that maintains all important LISA science at about half the cost and with reduced technical risk. It consists of three drag-free spacecraft in the most stable geocentric formation, the Earth-Moon L3, L4, and L5 Lagrange points.
Fixed antennas allow continuous contact with the Earth, solving the problem of communications bandwidth and latency. A 70 mm diameter AuPt sphere with a 35 mm gap to its enclosure serves as a single inertial reference per spacecraft, which is operated in "true" drag-free mode (no test mass forcing).

This is the core of the Modular Gravitational Reference Sensor (MGRS) whose other advantages are: a simple caging design based on the DISCOS 1972 drag-free mission, an all optical read-out with pm fine and nm coarse sensors, and the extensive technology heritage from the Honeywell gyroscopes, and the DISCOS and Gravity Probe B drag-free sensors.
An Interferometric Measurement System, designed with reflective optics and a highly stabilized frequency standard, performs the inter-test mass ranging and requires a single optical bench with one laser per spacecraft.
Two 20 cm diameter telescopes per spacecraft, each with in-field pointing, incorporate novel technology developed for advanced optical systems by Lockheed Martin, who also designed the spacecraft based on a multi-flight proven bus structure.
Additional technological advancements include the drag-free propulsion, thermal control, charge management systems, and materials. LAGRANGE sub-systems are designed to be scalable and modular, making them interchangeable with those of LISA or other gravitational science missions.
Critical technologies on are space qualified on small and nano satellite flights, with the first launch (UV-LED Sat) in 2013.

arXiv:1111.5264v2 [astro-ph.IM]

Last modified Mon, 6 May, 2013 at 19:34