The Department of Commerce National Telecommunications and Information Administration (NTIA) identified the Commerce Spectrum Advisory Committee (CSMAC) as the primary forum to facilitate technical discussions between industry and federal agencies regarding repurposing spectrum for commercial use. CSMAC Working Group 3(WG3) is focused on sharing of the 1755-1850 MHz band between federal satellite operations (SATOPS), DOD electronic warfare and commercial mobile wireless (MW) broadband. CSMAC...
Topics: DTIC Archive, AEROSPACE CORP EL SEGUNDO CA PHYSICAL SCIENCES LABS, *RADIO TRANSMISSION, *SATELLITE...
Purging is a common scheme to protect sensitive surfaces of payloads and spacecraft from airborne contaminant intrusion during ground assembly, integration, and launch vehicle encapsulation. However, the purge for space volumes must be occasionally interrupted. Thus, it is important to gain insights into the transport of ambient particles penetrating through vent holes and entering the interior of a confined space system, such as a space telescope, during a purge outage. This study presents...
Topics: DTIC Archive, AEROSPACE CORP EL SEGUNDO CA PHYSICAL SCIENCES LABS, *PURGING, *AEROSOLS,...
In preparation for the DebriSat hypervelocity impact test a Pre Preshot was conducted to validate the performance of the aluminum projectile to meet the velocity goal of 7 km/s and confirm operational status of test chamber and facility. The target was a multi-shock shield supplied by NASA which consisted of seven bumper panels consisting of fiberglass (E-glass, #1,2,4,5), stainless steel mesh (#3) and Kevlar (#6,7). In contrast to the DebriSat and Debris-LV impact tests, no soft catch panels...
Topics: DTIC Archive, AEROSPACE CORP EL SEGUNDO CA PHYSICAL SCIENCES LABS, *HYPERVELOCITY IMPACT,...
Five different life tests of SONY 18650-HC lithium-ion cells have been run for up to 10 years. These tests evaluate the 18650-HC lithium-ion cells under conditions ranging from rapid cycling at 32 cycles per day, to slow cycling at 90 cycles per year, to stand tests that involve no cycling at all. These tests examine the self-discharge of the cells, the divergence between cells in batteries, and their degradation rates as a function of the cycling rate and calendar life for cells manufactured...
Topics: DTIC Archive, AEROSPACE CORP EL SEGUNDO CA PHYSICAL SCIENCES LABS, *LITHIUM BATTERIES, *LIFE TESTS,...
This document reports the lot characterization and sample testing required for certification of a new lot of Moli-Energy Li-lon ICR-18650H 2200-mAh, 3.75-V cells to be used for a future picosatellite (PicoSat) or CubeSat flight experiment. Results from the required screening of 100% of the flight cells that constitute this new lot are also presented. All testing began upon receipt of the new cell lot in March 2(K)9 and was performed with the primary objective of flight certifying the cells...
Topics: DTIC Archive, AEROSPACE CORP EL SEGUNDO CA PHYSICAL SCIENCES LABS, *LITHIUM BATTERIES,...
As commercial and military systems become ever more dependent on GNSS, it becomes vitally important to ensure the health of the system's spacecraft atomic clocks. Though a number of methodologies for monitoring clock integrity are now under study/discussion, all have particular strengths and weaknesses; no one methodology achieves the ideal. More than likely, future GNSS will ensure clock integrity through a hybrid of techniques, and one component of that hybrid will certainly focus on the...
Topics: DTIC Archive, AEROSPACE CORP EL SEGUNDO CA PHYSICAL SCIENCES LABS, *SECOND HARMONIC GENERATION,...
Microtribological testing with a spherical diamond tip {radius = 100 pm) was conducted on two AU-M0S2 coatings with 32 at.% and 84 at.% Au. For lower loads (0.2 to 2.0 mN), the performance of both coatings was similar, with minimal wear (50 nm depth) and relatively stable friction coefficients. At higher loads (3,0- 5.0 mN), similar trends were found for the 84 at.% Au specimen, but the 32 at,% Au sample wore severely and the friction became unstable. Non-linear curve fitting of friction...
Topics: DTIC Archive, AEROSPACE CORP EL SEGUNDO CA PHYSICAL SCIENCES LABS, *MICROELECTROMECHANICAL SYSTEMS,...
Solid lubricant coatings with co-sputtered metal and MoS2 have shown favorable macrotribological properties at a wide range of contact stresses and humidity levels. These materials are also candidates for use in microcontacts and micro-electromechanical systems (MEMS), but their performance at this scale is poorly understood. For this study, microtribological properties of Au-MoS2 and Ti-MoS2 coatings, with varying metal additives of less than 15 at%, were examined using a nanoindentation...
Topics: DTIC Archive, AEROSPACE CORP EL SEGUNDO CA PHYSICAL SCIENCES LABS, *MOLYBDENUM COMPOUNDS, *SOLID...
In this work, we consider the light-shift coefficients observed in rubidium (Rb) atomic frequency standards, and how the units of measurement reported for light-shift coefficients trace back to the underlying physical parameters of the light-shift. We then measure the light-shift coefficient in an integrated filter-cell, commercial Rb clock, which is similar to the Rb clock design currently flying on Galileo and BeiDou satellites. We measure the light-shift coefficient for two different...
Topics: DTIC Archive, AEROSPACE CORP EL SEGUNDO CA PHYSICAL SCIENCES LABS, *ATOMIC CLOCKS, *FREQUENCY...
This report provides an analysis of the orbital performance of the three DMSP 5D3 spacecraft presently on orbit. The mission of the DMSP spacecraft is to collect and disseminate global high-resolution visible and thermal cloud cover imagery for DoD forces and the intelligence community. The present two-satellite constellation (early morning and mid morning) has an inclination of 98.7 with a 458 nmi sun synchronous polar orbit. The orbit period is I0l min with eclipses lasting up to 35 min. The...
Topics: DTIC Archive, AEROSPACE CORP EL SEGUNDO CA PHYSICAL SCIENCES LABS, *METEOROLOGICAL SATELLITES,...
The vapor-cell atomic clock finds application today in the global positioning system and telecommunications. To improve and miniaturize the humble device for future applications will require a deeper understanding of atomic and chemical physics.
Topics: DTIC Archive, AEROSPACE CORP EL SEGUNDO CA PHYSICAL SCIENCES LABS, *RUBIDIUM, *ATOMIC CLOCKS,...
