Goddard Space Flight Center.

Cover title.

Deliver us from evil; the story of Viet Nam's flight to freedom.

Mode of access: Internet.

Flight Mechanics/Estimation Theory Symposium 1992 : proceedings of a symposium sponsored by NASA Goddard Space Flight Center and held at Goddard Space Flight Center, Greenbelt, Maryland, May 5-7, 1992 /

Includes bibliographical references.

Propulsion systems for space flight.

Includes bibliography.

Stress waves in a temperature dependent viscoelastic half-space subjected to impulsive electromagnetic radiation,

Cover title.

Space flight.

v.1. Environmental and celestial mechanics. v.2. Dynamics.

A Periodic State Space Model to Monthly Long-term Temperature Data

This work presents a periodic state space model to model monthly temperature data. Additionally, some issues are discussed, as the parameter estimation or the Kalman filter recursions adapted to a periodic model. This framework is applied to monthly long-term temperature time series of Lisbon.

What's new on the moon? /

Cover title.

Preliminary results from the infrared multilayer filters and materials exposed to the space environment on the NASA LDEF mission

With continually increasing demands for improvements to atmospheric and planetary remote-sensing instrumentation, for both high optical system performance and extended operational lifetimes, an investigation to access the effects of prolonged exposure of the space environment to a series of infrared interference filters and optical materials was promoted on the NASA LDEF mission. The NASA Long Duration Exposure Facility (LDEF) was launchd by the Space Shuttle to transport various science and technology experiments both to and from space, providing investigators with the opportunity to study the effects of the space environment on materials and systems used in space-flight applications. Preliminary results to be discussed consist of transmission measurements obtained and processed from an infrared spectrophotometer both before (1983) and after (1990) exposure compared with unexposed control specimens, together with results of detailed microscopic and general visual examinations performed on the experiment. The principle lead telluride (PbTe) and Zinc Sulphide (ZnS) based multilayer filters selected for this preliminary investigation consist of : an 8-12µm low pass edge filter, a 10.6µm 2.5% half bandwidth (HBW) double half-wave narrow bandpass filter, and a 10% HBW triple half-wave wide bandpass filter at 15µm. Optical substrates of MgF2 and KRS-5 (T1BrI) will also be discussed.

Mercury Project summary including results of the fourth manned orbital flight, May 15 and 16, 1963.

Mode of access: Internet.