Engineering topics
Publications and source records attributed to Ehrmann, C. H..
The High Energy Gamma Ray Balloon Instrument was built in part to verify certain subsystems' performance for the Energetic Gamma Ray Experiment Telescope (EGRET) instrument, the high energy telescope to be carried on the Gamma Ray Observatory. This paper describes the instrument, the performance of some subsystems, and some relevant results.
This paper describes the application of a single-chip microcomputer in a high-altitude balloon instrumentation system. The system, consisting of a magnetometer, a stepping motor, a microcomputer and a gray code shaft encoder, is used to provide an orientation reference to point a scientific instrument at an object in space. The single-chip microcomputer, Intel's 8748, consisting of a CPU, program memory, data memory and I/O ports, is used to control the orientation of the system.
The high energy gamma-ray telescope selected for definition studies on the Gamma Ray Observatory provides a substantial improvement in observational capability over earlier instruments. It will have about 20 times more sensitivity, cover a much broader energy range, have considerably better energy resolution and provide a significantly improved angular resolution. The design and performance are described.
The high energy gamma-ray selected for definition studies on the Gamma Ray Observatory provides a substantial improvement in observational capability over earlier instruments. It will have about 20 times more sensitivity, cover a much broader energy range, have considerably better energy resolution and provide a significantly improved angular resolution. The design and performance are described.
An effort has been made within NASA to produce a low-cost modular system for implementation of Shuttle payloads based on the CAMAC standards for packaging and data transfer. A key element of such a modular system is a means for controlling the data system, collecting and processing the data for transmission to the ground, and issuing commands to the instrument either from the ground or based on the data collected. A description is presented of such a means based on a network of digital processors and CAMAC crate controllers, which allows for the implementation of instruments ranging from those requiring only a single CAMAC crate of functional modules and no data processing to ones requiring multiple crates and multiple data processors.
A set of standard CAMAC modules for Spacelab payloads is being developed by NASA. A crate controller, a processor module, memory modules and a databus to connect them are being developed at the Goddard Space Flight Center. These components will provide for the implementation of CAMAC data systems ranging in complexity from fixed-format, single-crate data collection systems not requiring a processor to a multi-crate data system, including several computers (processors). The Spacelab CAMAC data system is introduced with the role of the crate controller described. The implementation and operation of the crate controller is described. The instruction set of the crate controller is also presented.
The advent of the Shuttle launch vehicle and Spacelab have resulted in adequate weight and volume such that experiment electronics can be implemented at relatively low cost using spaceflight versions of CAMAC and NIM modules. Studies of 10 modules by manufacturers have shown that power reduction overall by a factor of about 3 can be accomplished. This is adequate both from the point of view of consumption and temperature rise in vacuum. Our studies have shown that a stock of about 45 module types is required and a listing is given. The changes required in these modules in order to produce spaceflight versions are described. And finally, the further studies, prototyping and testing leading to eventual flight qualification are described.
The applicability of CAMAC and NIM to various payloads was studied. A major result is summarized in tabular form showing the applicability of standard available CAMAC and NIM modules to the six experimental payloads chosen. It was concluded that CAMAC has wide applicability within the experiments considered.
The CAMAC and NIM instrumentation systems were developed originally to serve the needs of nuclear research institutions in Europe and North America. CAMAC and NIM are currently considered in several studies at the systems level conducted by NASA and ESRO groups. NIM and CAMAC studies for applications related to the space shuttle are discussed along with the advantages provided by aspects of modularization and standardization, a use of NIM and CAMAC equipment in connection with a group of astrophysics experiments, and questions of cost effectiveness.
A magnetic core digitized spark chamber gamma ray telescope has been developed for satellite use. The detector has the following characteristics: effective area = 500 cu/cm, solid angle = 1/4 SR; efficiency (high energy) = 0.29; and time resolution of better than two milliseconds.
Systems description of SAS-B gamma ray telescope with multilayer digitized spark chamber for gamma rays with energy exceeding 20 MeV
Density measurements of particle tracks in nuclear emulsions utilizing digitized video scan, discussing operation and instrumentation
Gamma ray telescope development for balloon-borne astronomy in search for discrete gamma sources and supernova explosions
Gamma ray telescope utilizing wire spark chamber for balloon borne astronomy
Computer analysis of density measurements of particle tracks in nuclear emulsions by use of digitized video scan
Magnetometer systems on Pioneers 6, 7, and 8 to study interplanetary magnetic fields
Cosmic gamma radiation point sources from high altitude balloon flights
High altitude balloon magnetic-core digitized spark chamber detector system for determining point sources of cosmic gamma radiation