NASA Scientific and Technical Aerospace Reports

approximately the same values, i.e. few cm. These conditions are expected to be observed in the ionosphere at the altitude of
approximately 700 km and therefore our model may be directly applied for the interpretation of the current measurements on
the board the DEMETER satellite.
Author
Electrostatic Probes; Plasma Probes; Thermal Plasmas; Space Plasmas; Measuring Instruments; Electric Current
20040111102 Centre National de la Recherche Scientifique, Toulouse, France
In-Flight Anomalies Attributed to ESD’s. Recent Cases and Trends
Catani, Jean-Pierre; 8th Spacecraft Charging Technology Conference; March 2004; 8 pp.; In English; See also 20040111031;
No Copyright; Avail: CASI; A02, Hardcopy
The general problem of charging is usually shared out four domains of physics or technology: astrophysics for the
knowledge of environment, materials technology for understanding and prediction of charge build-up, plasma physics for
predicting thermal or electromagnetic effects of discharges, and space engineering for assessing effects of transients on the
space system. The environment monitoring at the geosynchronous altitude has been carried out for years beginning with the
first launches of NOAA GOES satellites. Their drawback is they provide only local data. The development of Space Weather
activities let foresee the possibility of deriving the charging particles content in the immediate vicinity of the space vehicle
from a limited set of flight-monitored data. Today, anomalies attributed to charging are fortunately infrequent, making
unreliable statistical correlation between environmental data and event occurrence. It can be conclusive only in some cases
of surface charging. The understanding of interaction of materials with a well-representative simulation of environment is a
priority in Europe, especially at CNES, the French Space Agency. In a CNES/ONERA test facility in Toulouse the main
features leading to both surface and internal charging are simulated for all altitudes. An aim is the characterization of new
technologies and new materials: electrical thrusters, active antennas, conductive coatings. Another aim is the issuing of design
rules in the frame of the European Space Standardization. The plasma discharge is the source of an electromagnetic field
transient. At equipment level an ElectoStatic Discharge (ESD) immunity test has been used for now fifteen years. A system
level test remains to be defined.
Author
Electromagnetic Fields; Spacecraft Charging; Electrostatic Charge; Spacecraft Environments; Spacecraft Instruments;
Electric Discharges
20040111107 European Space Agency, Greenbelt, MD, USA
Space Weather Effects on SOHO and its Role as a Space Weather Watchdog
Brekke, P.; Fleck, B.; Haugan, S. V.; vanOverbeek, T.; Schweitzer, H.; Chaloupy, M.; 8th Spacecraft Charging Technology
Conference; March 2004; 13 pp.; In English; See also 20040111031; No Copyright; Avail: CASI; A03, Hardcopy
Since its launch on 2 December 1995, the Solar and Heliospheric Observatory (SOHO) has provided an unparalleled
breadth and depth of information about the Sun, from its interior, through the hot and dynamic atmosphere, and out to the solar
wind. In addition SOHO has several times demonstrated its leading role in the early-warning system for space weather. SOHO
is in a halo orbit around L1 Lagrangian point where it views the Sun 24 hours a day. Thus, it is situated outside the Earth’s
protective magnetosphere which shields other satellites from high energy particles and the solar wind. We present a summary
of the observed effects on the instruments and electronics on SOHO throughout the mission. In particular we focus on a
number of large particle events during the recent years while the Sun was approaching maximum activity, and how they
affected both the scientific data as well as hardware components.
Author
Soho Mission; Space Weather; Spacecraft Design; Spacecraft Instruments
20040111311 NASA Langley Research Center, Hampton, VA, USA
In-Flight Thermal Performance of the Lidar In-Space Technology Experiment
Roettker, William; [1995]; 9 pp.; In English
Report No.(s): AIAA Paper 95-2016; Copyright; Avail: CASI; A02, Hardcopy
The Lidar In-Space Technology Experiment (LITE) was developed at NASA s Langley Research Center to explore the
applications of lidar operated from an orbital platform. As a technology demonstration experiment, LITE was developed to
gain experience designing and building future operational orbiting lidar systems. Since LITE was the first lidar system to be
flown in space, an important objective was to validate instrument design principles in such areas as thermal control, laser
performance, instrument alignment and control, and autonomous operations. Thermal and structural analysis models of the
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