Joseph M. Flatico

Development of a Mars dust characterization instrument

Abstract The atmosphere of Mars has a considerable load of suspended dust. Over time, this dust deposits out of the atmosphere. The mechanism and the temporal and geographical variation of this deposition are not well characterized. Measurements of settling rates and dust properties are of considerable scientific interest. Suspended dust affects the atmospheric solar absorption and thus the heat balance of Mars, as well as serving as nucleation sites for water and CO2 frost, while settled dust causes albedo changes across the surface; knowledge of dust properties is also of engineering interest to the design of mechanisms, solar arrays, and radiators. Two instruments have been designed and fabricated to measure the dust accumulation during the course of the Mars Pathfinder rover mission: a solar-cell coverglass transmission experiment to measure the change in optical opacity of a transparent coverglass as dust settles on the surface and a quartz crystal monitor to measure the mass of dust deposited on an oscillating quartz crystal as dust settles on the surface. An additional instrument, a CCD microscope to image individual dust particles is under development for flight on a future mission.

MISSE7: Building a Permanent Environmental Testbed for the International Space Station

The Materials on the International Space Station Experiments (MISSE) provide low‐cost material exposure experiments on the exterior of the International Space Station (ISS). The original concept for a suitcase‐like box bolted to the ISS to passively expose materials to space has grown to include increasingly complex in situ characterization. As the ISS completes construction, the facilities available to MISSE experiments will increase dramatically. MISSE7 is the first MISSE to take advantage of this new infrastructure. In addition to material exposure, MISSE7 will include characterization of single‐event radiation effects on electronics and solar cell performance in LEO. MISSE7 will exploit the ISS Express Logistics Carrier power and data capabilities and will leave behind a MISSE specific infrastructure for future missions.

Initial results from the second Forward Technology Solar Cell Experiment

The success of the first Forward Technology Solar Cell Experiment (FTSCE) which flew as part of the 5th Materials on the International Space Station Experiments (MISSE-5) [1,2,3], led to a follow on experiment, FTSCE II. This experiment is currently operating on the International Space Station (ISS) as part of MISSE7. Solar cells are characterized with I–V curves. The test cells include current and next generation triple-junction production cells from Emcore and Spectrolab as well as advanced inverted metamorphic (IMM) and other thin film III–V cells from Emcore, Spectrolab and MicroLink Devices, Inc. Other thin film technologies include, advanced amorphous silicon concepts from United Solar Ovonic and a Copper Indium Selenide based two-cell string from Dutch Space. In this paper, The FTSCE II experiment is described and current status presented.

Development of Hyperspectral remote sensing capability for the early detection and monitoring of Harmful Algal Blooms (HABs) in the Great Lakes

Hyperspectral imagers have significant capability for detecting and classifying waterborne constituents. One particularly appropriate application of such instruments in the Great Lakes is to detect and monitor the development of potentially Harmful Algal Blooms (HABs). Two generations of small hyperspectral imagers have been built and tested for aircraft based monitoring of harmful algal blooms. In this paper a discussion of the two instruments as well as field studies conducted using these instruments will be presented. During the second field study, in situ reflectance data was obtained from the Research Vessel Lake Guardian in conjunction with reflectance data obtained with the hyperspectral imager from overflights of the same locations. A comparison of these two data sets shows that the airborne hyperspectral imager closely matches measurements obtained from instruments on the lake surface and thus positively supports its utilization for detecting and monitoring HABs.

In-flight performance of III-V multi-junction solar cells from the Forward Technology Solar Cell Experiment

The Materials on the International Space Station Experiments (MISSE) present a unique opportunity in space science by offering a low-cost platform to expose materials directly to the space environment on the International Space Station (ISS). MISSE experiments consist of a “suitcase” like package known as the “Passive Experiment Carrier” (PEC) that can be carried by astronauts and mounted externally to the ISS. The 5th MISSE payload (MISSE-5) contained both passive and active experiments. The Forward Technology Solar Cell Experiment (FTSCE) on MISSE-5 measured current-voltage (I–V) characteristics on 36 solar cells of various types. Over 1500 I–V curves were recorded on each cell during a 13-month period. This paper analyses the results for all the III–V multi-junction cells flown, including state-of-the-art space qualified cells and next generation metamorphic cells.

CIB: An Improved Communication Architecture for Real-Time Monitoring of Aerospace Materials, Instruments, and Sensors on the ISS

The Communications Interface Board (CIB) is an improved communications architecture that was demonstrated on the International Space Station (ISS). ISS communication interfaces allowing for real-time telemetry and health monitoring require a significant amount of development. The CIB simplifies the communications interface to the ISS for real-time health monitoring, telemetry, and control of resident sensors or experiments. With a simpler interface available to the telemetry bus, more sensors or experiments may be flown. The CIB accomplishes this by acting as a bridge between the ISS MIL-STD-1553 low-rate telemetry (LRT) bus and the sensors allowing for two-way command and telemetry data transfer. The CIB was designed to be highly reliable and radiation hard for an extended flight in low Earth orbit (LEO) and has been proven with over 40 months of flight operation on the outside of ISS supporting two sets of flight experiments. Since the CIB is currently operating in flight on the ISS, recent results of operations will be provided. Additionally, as a vehicle health monitoring enabling technology, an overview and results from two experiments enabled by the CIB will be provided. Future applications for vehicle health monitoring utilizing the CIB architecture will also be discussed.

Fourier transform spectrometry for fiber-optic sensor systems

An integrated-optic Mach-Zehnder interferometer is used as a Fourier transform spectrometer to analyze the input and output spectra of a temperature-sensing thin-film etalon. This type of spectrometer has an advantage over conventional grating spectrometers because it is better suited for use with time-division-multiplexed sensor networks. In addition, this spectrometer has the potential for low cost due to its use of a component that could be manufactured in large quantities for the optical communications industry.

Fiber optic thermometer using Fourier transform spectroscopy

An integrated-optic Mach-Zender interferometer is used as a Fourier transform spectrometer to analyze the input and output spectra of a temperature-sensing thin-film etalon. This configuration provides a high degree of immunity to the effects of changes in the source spectrum, and it readily permits the interrogation of a number of different sensors using a single spectrometer. In addition, this system has a potentially low cost because it uses optical communications hardware that may in the future be manufactured in large quantities.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.