High-shock FM transmitter Final report, phase I
Electronic component testing of high-shock FM TRANSMITTERS
SHOCK SENSITIVITY↗
SEARCH · Engineering Papers
Results for “transmittance”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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High shock FM transmitter Final report, phase II
Electric and impact shock testing of prototype and final design high shock FM transmitter
RADIO TRANSMITTER↗
High power microwave transmitters for deep space communications with unmanned spacecraft.
High-power microwave transmitters for deep-space communication with unmanned spacecraft
SPACE COMMUNICATION↗
Observation of absorption edges in the extreme ultraviolet by transmittance measurements through thin unbacked metal films.
X-ray absorption edge observation by transmittance measurements through thin unbacked metal films in XUV as function of wavelength
METAL FILM↗
High power C.W. radar transmitter, chapter 23
High power continuous wave radar transmitter for use as planetary radar system and as proving ground for equipment NASA space program
TRANSMITTER↗
MSFN transmitters
Implementation and testing of Deep Space Network Manned Space Flight Network transmitters
DEEP SPACE INSTRUMENTATION FACILITY /DSIF/↗
Advanced transmitter development
Testing of high voltage power supply and linear exciter for Mariner transmitter noise amplitude modulation
SILICON CONTROL RECTIFIER /SCR/↗
Optical transmittance of fused silica at elevated temperatures.
Optical transmittance of fused silica at elevated temperatures, showing shift in UV to IR ABSORPTION with increasing temperature
ULTRAVIOLET SPECTRUM↗
High power C.W. radar transmitter.
High power CW radar transmitter, discussing design parameters, development and performance characteristics
RADIO TRANSMITTER↗
Development of a new 20kW CW transmitter for 34-meter antennas of NASA's Deep Space Network
A next generation of 20kW dual-band transmitters was developed for NASA's Deep Space Network 34m Beam Waveguide antennas.
DSN Transmitter↗
New 20-kW CW transmitter for NASA's Deep Space Network
A 20-kW S- and X-Band transmitter was developed for NASA's Deep Space Network (DSN) 70-m antennas.
acquisition instrumentation X-band S-band↗
Relative Water Content, Bidirectional Reflectance and Bidirectional Transmittance of the Interior of Detached Leaves During Dry Down.
Remotely sensing the water status of plants and the water content of canopies remain long-term goals of remote sensing research [1]. Estimates of canopy water content commonly involve measurements in the 900nm to 2000nm portion of the optical spectrum [1]. We have used optical polarization techniques to remove leaf surface reflection and to demonstrate that the visible light reflected by the interior of green healthy corn leaves measured in situ inversely depends upon the leaf relative water content (RWC) [2]. In the research reported here, we again used optical polarization techniques in order to remove the leaf surface reflection from our measurements. This allowed us to monitor the interiors of detached corn leaf samples during leaf dry down measuring for each sample the RWC, bidirectional spectral reflectance and bidirectional spectral transmittance over the wavelength range 450nm to 2,500nm. Our new results like our earlier results show light scattered by the leaf interior measured in the visible wavelength region generally increased as leaf RWC decreased. However, the spectral character and the much improved signal noise of our new results shows the RWC-linked visible light scattering changes are due to leaf structural changes. Our new results show that scattering changes that occur with changing leaf RWC are not attributable to molecular configuration changes in cellular pigments.
Corn↗
Estimating Leaf Water Status from Vis-Nir Reflectance and Transmittance
Remotely sensing the water status of plant canopies remains a long term goal of remote sensing research. Established approaches involve measurements in the thermal infrared and the 900-2000nm reflective infrared. Less popular UV-visible-NIR techniques presumably deserve research attention, because photochemical changes linked to plant water status manifest spectral light scattering and absorption changes. Here we monitored the visible and NIR light reflected from the leaf interior as well as the leaf transmittance as the relative water content of corn (Zeamays L.) leaves decreased. Our results highlight the importance of both scattering effects and effects due to absorption by leaf pigments.
VIS-NIR Reflectance↗
Design of a 2.5 Gbps Optical Transmitter for the International Space Station
A high data rate laser transmitter assembly (LTA) has been designed as the source for an optical free-space communication link between the International Space Station and the 1-meter Optical Communications Telescope Laboratory (OCTL) to be built at the Table Mountain Facility (TMF, Wrightwood, CA).
Optical↗
Laser Transmitter Assembly for Optical Communication Demonstrator
A modulated fiber-coupled diode laser assemby has been developed. This module will serve as the laser transmitter assembly for the Optical Communication Demonstrator (OCD) system. The laser is capable of greater than 20mW of output at 100 Mbps Q-PPM modulation.
Laser↗
New Millenium Deep Space Tiny Transmitter: First Phase of a Digital Transponder
An advanced technology X- and Ka-band (8 and 32 GHz) Tiny Transmitter is being developed at JPL for the New Millenium program and is described in this paper. The Tiny Transponder is the first phase of development of the Tiny Transponder which will incorporate recent advancements in miniaturization and flexibility of radio systems by utilizing digital radio techniques.
Cassini↗
Independent Reliability Assessment of the NASA GSFC Laser Transmitter for the LISA Program
The Laser Interferometer Space Antenna (LISA) is a partnership between the European Space Agency (ESA) and NASA to build a Gravitational Wave (GW) observatory. The observatory, which consists of a three-spacecraft constellation with a nominal separation of 2.5 million km between each spacecraft, provides a tool for scientists to directly detect gravitational waves generated from various astronomical phenomena in a waveband that is not accessible from Earth. NASA is developing laser transmitters as one of the potential US contributions to LISA. The NASA laser design leverages lessons learned from previous flight missions and included the latest technologies in photonics packaging and reliability engineering to ensure a laser lifetime of >16 years covering integration and test through a possible extended mission phase. As part of the laser development process, NASA’s Goddard Space Flight Center (GSFC) requested support from the NASA Engineering and Safety Center (NESC) to independently assess the Technology Readiness Level (TRL) of the LISA Laser System (LS). The independent assessment included the following tasks: (a) assess the design for weaknesses and suggest improvements to mitigate risks, (b) assess the laser reliability plan for weaknesses and suggest improvements to mitigate risks and improve effectiveness, and (c) assess the current redundancy plan on laser subsystems for weaknesses and suggest improvements to mitigate risks and improve effectiveness. The NESC team comprised of a team of subject matter experts (SMEs) and performed a 12-month review of every aspect of the laser design. We present the assessment findings and the current development progress of the LISA laser to meet the mission requirements with a delivery of a form, fit, and functional TRL6 laser to the LSIA mission by late 2023.
LISA↗
Deficiency in transmitter release triggers homeostatic transcriptional changes that increase presynaptic excitability
Weakening of synaptic transmission at theDrosophilalarval neuromuscular junction triggers two forms of homeostatic compensation, one that increases the probability of glutamate release per action potential (P r ) and another that increases motoneuron (MN) activity. We investigated the molecular changes in MNs that underlie the increase in MN activity. RNA sequencing (RNA-seq) analysis on MNs whose glutamate release is weakened by knockdown of components of the MN transmitter release machinery reveals a reduction in expression of a group of genes that encode potassium channels and their positive modulators. These results identify a mechanism of compensation for weakened synaptic transmission by MNs, which engages a transcriptional program in those cells to increase firing and, thereby, ensure sufficient locomotory drive.
Science & Technology - Other Topics↗