Development of the Mars Observer Laser Altimeter (MOLA)

The Mars Observer (MO) spacecraft payload scientific mission is to gather data on Martian global topography, gravity, weather, magnetic field and its interaction with the solar flux, surface chemistry, and mineralogy over one Mars year. In mid-1988 the need for a replacement altimeter as part of the payload complement arose. The Mars Observer Laser Altimeter (MOLA) was proposed by GSFC as an in-house effort and shortly afterward was 'conditionally' accepted. Constraints on funding, schedule, power, and mass were imposed with periodic reviews during the instrument development to authorize continuation. MOLA was designed, tested, and delivered in less than 36 months and integrated with the spacecraft. During spacecraft payload testing, the laser failed due to contamination in the laser cavity. In only 6 months, the laser was removed, rebuilt from spare parts, retested, and the instrument reassembled, realigned, requalified, and again delivered for spacecraft integration. Other aspects of the development of the MOLA are presented

Special function models of indecomposable sl(2)sl(2) representations: The Laguerre Case

In this paper, we point out connections between certain types of indecomposable representations of $sl(2)$ and generalizations of well-known orthogonal polynomials. Those representations take the form of infinite dimensional chains of weight or generalised weight spaces, for which the Cartan generator acts in a diagonal way or via Jordan blocks. The other generators of the Lie algebras $sl(2)$ act as raising and lowering operators but are now allowed to relate the different chains as well. In addition, we construct generating functions, we calculate the action of the Casimir invariant and present relations to systems of non-homogeneous second-order coupled differential equations. We present different properties as higher-order linear differential equations for building blocks taking the form of one variable polynomials. We also present insight into the zeroes and recurrence relations

A History of Jefferson Barracks, 1826-1860.

Jefferson Barracks was established in 1826 and was one of the army\u27s major posts until 1860. Located twenty-six miles below the confluence of the Missouri and Mississippi Rivers, the Barracks served as a concentration point for supplies for the various army installations in the Missouri River valley and along the upper Mississippi and its tributaries. When Jefferson Barracks was established, the army intended for the post to act as the Infantry School of Instruction, but the School was never formally organized. The first soldiers stationed at the post were required to construct their own barracks and other auxillary buildings, and when they finished constructing their barracks, they were needed to fight in the Black Hawk War of 1832. Jefferson Barracks played an important role in the nation\u27s changing military policy following the Black Hawk War. The Barracks was the training site for the First Dragoons, which Congress established in 1833, and also was the location of the central reserve force for the western frontier. Utilizing its strategic location on the Mississippi, the reserve force at Jefferson Barracks could quickly reach the western frontier regions in order to overawe the Indians or protect United States\u27 possessions from any foreign threat. This reserve force was not established at Jefferson Barracks until 1843, because the soldiers at the post were needed to fight in the Second Seminole War. Even after the western strategic force was placed at Jefferson Barracks, it did not remain at the post for long. In 1844, the War Department ordered all available soldiers at Jefferson Barracks to proceed to Texas to defend against hostile actions by the Mexican government. Following the end of the Mexican War, in 1848, Jefferson Barracks resumed its primary role as a recruit and supply depot for the western frontier army. Throughout the entire period 1826-1860, Jefferson Barracks had a close and important relationship with St. Louis. Jefferson Barracks offered excellent business and employment opportunities to numerous St. Louisians, and they looked upon the Barracks as a regional economic asset. The primary source of materials used in the preparation of this dissertation were the records of the several divisions of the War Department in the National Archives. Among the most important were Records Groups 92 (Records of the Office of Quartermaster General), 94 (Records of the Adjutant General\u27s Office), 98 (Records of the United States Army Commands), 107 (Records of the Office of Secretary of War), 108 (Records of the Headquarters of the Army), and 153 (Records of the Office of the Judge Advocate General). Additional useful information was obtained from various other government documents, the archives of the Missouri State Historical Society in St. Louis, and the St. Louis newspapers