LISA
LISA
Abbrev. for Laser Interferometer Space Antenna. A ‘cornerstone’ mission of ESA's Horizon 2000 program aimed at detecting and observing gravitational waves from massive black holes and binary stars in our Galaxy. The mission will seek to operate at frequencies between 0.1 and 0.0001 Hz, a range in which no useful groundbased measurements can be made. The LISA mission will consist of six identical spacecraft deployed in space in the configuration of an equilateral triangle having each side 5 million km long. Each spacecraft will carry a miniature laser emitting a continuous infrared beam at a wavelength of 1.064 μm. Each of the LISA craft will transmit the beam to its corresponding remote counterpart in the configuration via a 38-cm-aperture Cassegrain telescope and will in turn receive the much weaker return beam via the same telescope. Each telescope will focus the return beam it receives onto a sensitive photodetector where it will be superimposed with a small part of the original local light. The resulting interference signal from each arm of the triangle will be combined under computer control to screen out local phase noise. A polished platinum-gold cube (known as a test mass) inside a vacuum enclosure carried by each vehicle will serve as an optical reference (mirror) for the light beams. Any gravitational wave passing through the system should cause a fluctuation in the separation of the test masses and a concomitant fluctuation in the optical pathway between the test masses, and this should be detectable by the interferometry. Such a fluctuation will be extremely small but should be measurable. The mission is currently planned for launch in 2017.Lisa
LISA
(computer)A personal computer introduced by Apple Computer, Inc. in1983. The LISA was a predecessor of the Macintosh and wasthe first personal computer on the market with a graphical user interface.
It was origionally named after Steve Jobs's daughter. Theacronym was applied later.
LISA
(tool)FTP MIT.
LISA
(event)Lisa
The first personal computer to include integrated software and use a graphical interface. Modeled after the Xerox Star and introduced in 1983 by Apple, it was ahead of its time but never caught on due to its USD $10,000 price and slow speed. Named after Steve Jobs' daughter, the Lisa gave way to the Macintosh, which was developed by a separate group within Apple. In fact, the final production units of the Lisa were modified into a somewhat-compatible version of the Macintosh. |
| The Lisa |
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| It was as slow as molasses, but users were entranced by its graphical interface and ability to cut and paste between applications. (Image courtesy of AUCTION TEAM BREKER, Cologne, Germany, (c) 2013, www.breker.com) |