@prefix ns0: . @prefix skos: . ns0:altLabel [ ] ; skos:definition """Laser ranging observatories are located around the world. There are three kinds of stations; fixed, movable and highly mobile. In a fixed system, the laser is permanently located at a pier or foundation that does not change position. The movable systems are different. NASA operates four stations known as Mobile Laser Ranging Systems (MOBLAS), in movable locations. MOBLAS usually consist of two trailer vans which can be driven to a given observing location and set up for an observing session that will then last for months or years at that site. Because of the time-consuming setup and breakdown process, these movable systems are rarely moved. The MOBLAS at Goddard is one of three NASA SLR's located in North America. The fourth is in Yarragadee, Australia. Four of the NASA stations are the highly-mobile type called Transportable Laser Ranging Systems (TLRS). They are newer systems which are smaller versions of the fixed and movable SLR systems. They are complete systems able to operate from a pad accessible by road, and require relatively short setup and breakdown times. Because of the need to sample the orbit of the retroreflector satellite, however, the duration of recording is generally measured in terms of weeks to months. These have been placed in locations such as Chile, French Polynesia, Peru and several sites in North America, Mexico and Europe. The other two NASA systems are fixed systems located in Texas and Hawaii and are operated for NASA by local universities. [Summary provided by NASA]"""@en ; skos:prefLabel "MOBLAS"@en ; skos:inScheme ; skos:broader ; a skos:Concept . skos:prefLabel "Laser Ranging"@en ; a skos:Concept ; skos:narrower .