Building Circuit Models of Internal Electrostatic Discharge Events
No abstract provided
Martin, Eduardo↗
Engineering topics
Martin, Eduardo
Publications and source records attributed to Martin, Eduardo.
Electrostatic Discharges from Conductive Thermal Coatings
Selecting the correct thermal control coating for a spacecraft can be a significant challenge. From the start, the process includes balancing conflicting needs. Thermal control paints must have the ability to either absorb or emit heat as desired and this property cannot change beyond a set point over the life of the mission. When the mission involves operating in a heavy charging environment, the control coating must be static dissipative enough to bleed away absorbed energetic electrons to minimize induced electric fields and the risk of electrostatic discharges. Finding the right balance of thermal performance and electrical performance can be difficult for spacecraft designers. In an effort to aid in spacecraft design, a number of white and black thermal control coatings were tested at the Jet Propulsion Laboratory using a two-part test campaign. These tests involved an initial screening test to determine the bulk resistivity of the material using a traditional parallel plate test, but placed in a vacuum chamber immersed in a bath of liquid nitrogen to obtain data over a range of temperatures. The most promising materials were then exposed to a stream of energetic electrons and monitored for the production of electrostatic discharges. Results from these tests indicated that only a few of the common thermal control coatings have a resistivity below 109 ohm-cm as suggested in NASA-HDBK-4002A. Of those that meet this criterion, most will still produce electrostatic discharges when exposed to electrons with energies from 20keV to 60keV while held at cryogenic temperatures. Additional testing is required to characterize additional coatings to create a database that designers may use when selecting an appropriate coating for their application.
Chinn, James↗
Internal Electrostatic Discharge Tests of Micro-D Connectors for Planned Europa Mission
NASA has planned a mission to study Jupiter’s moon, Europa. The mission would place a spacecraft into orbit around Jupiter, performing nominally 45 flybys of the moon. The suite of instruments onboard the spacecraft would investigate Europa’s potential to sustain life, studying the moon’s atmosphere, water-ice crust, suspected subsurface ocean, and rocky interior. The radiation environment at Europa’s orbit is severe and presents a significant threat to the spacecraft. There are several radiation effects that could be problematic, one of which is internal charging. Problems due to internal charging arise when high energy electrons penetrate the spacecraft and deposit within onboard dielectrics or floating metals. These charges can build up over time, generating electric fields that exceed the breakdown strength of materials in the region. A rapid discharge of the stored charges may occur, sending current pulses into electronics and potentially damaging them. An Internal Electrostatic Discharge (IESD) design environment was created for the planned Europa mission [Kim et al, in press]. The IESD design environment is meant to characterize the part of the radiation environment that poses the largest threat to the spacecraft with respect to internal charging. The environment was based off of electron data gathered by the Galileo spacecraft. Over the past year, the internal charging threat to several hardware components of the planned Europa Clipper spacecraft have been characterized using simulations and/or tests. The subject report documents one such test on Micro-D connectors.
Smithfield, Marianne↗
Internal electrostatic discharge tests of Micro-D connectors for planned Europa mission
UNKNOWN
Smithfield, Marianne↗
Origins, Evolution, and Fate of Brown Dwarfs
Research related to the origins, evolution and fate of brown dwarfs is presented. The topics include: 1) Imaging surveys for brown dwarfs; 2) Companion detection techniques; 3) Measurements of fundamental properties of brown dwarfs; 4) Classification schemes for ultracool dwarfs; 5) Origins and evolution of brown dwarfs; 6) Ultracool atmospheres and interiors; 7) Time variable phenomena in brown dwarfs; 8) Comparisons between brown dwarfs and planets; 9) Substellar mass functions; and 10) Future facilities.
Martin, Eduardo↗
Search for X-Ray Emission in the Nearest Known Brown Dwarf
The XMM observation were obtained on 2001 January 07-08 for 51767 s. The Optical Monitor (OM) was used with the V filter for 4 exposures of 5000 s each in imaging mode. We used the data given by the OM to confirm the presence of the source in the field of view. The European Photon Imaging Camera (EPIC) MOS 1 and MOS2 were used 48724 s each in prime full window mode with 2.5 s time resolution. The EPIC PN was used 46618 s in prime full window mode with 73.4 ms time resolution. The X-ray source closest to the expected position of our target is offset by delta R.A=2.5 arcsec and delta Dec=-28.37 arcsec. This offset is high in comparison with the 0.4 arcsec observed with the optical data. So at this point we already knew that the target was not detected. To confirm that conclusion, we performed the identification of all X-ray sources in the field of view by comparing source to source our image with the one obtained by Rutledge et al. with Chandra. This allowed us to identify all the X-ray sources in our field of view in an area of 20 arcsec times 10 arcsec centered on the expected coordinates of LP944-20. We were then able to conclude that the target was not detected during this observation. This result allowed us to determine a new and better 3 sigma upper limit of X-Ray emission for this object. We have also derived duty cycles for X-ray flares as a function of X-ray luminosity by comparing the XMM data with Chandra and ROSAT data. One student has been supported with the grant during four months (Herve Bouy). A Sun workstation was purchased for him.
Martin, Eduardo↗
Search for X-Ray Emission in the Nearest Known Brown Dwarf
The XMM observations were obtained on 2001 January 07-08 for 51767 s. The Optical Monitor (OM) was used with the V filter for four exposures of 5000 s each in imaging mode. We used the data given by the OM to confirm the presence of the source in the field of view. The European Photon Imaging Camera (EPIC) MOS1 (Metal Oxide Semiconductor) and MOS2 were used 48724 s each in prime full window mode with 2.5 s time resolution. The EPIC PN was used 46618 s in prime full window mode with 73.4 ms time resolution.
Martin, Eduardo↗