Joseph P. Skura

The MESSENGER Science Planning and Commanding System

MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is the first spacecraft to visit Mercury since the Mariner 10 flybys in 1974 and 1975 and will be the first spacecraft to orbit the innermost planet, beginning in March 2011. The science payload is designed to study all aspects of Mercury and its environment and consists of seven instruments and a radio science experiment. During the primary orbital phase of the mission, the MESSENGER team faces the challenge of scheduling science observations to meet all measurement objectives while operating in a thermally harsh environment in geometrically challenging orbits. An efficient, automated science planning and commanding system called MESSENGER SciBox has been developed to support orbital analysis and strategic planning activities prior to orbital insertion, and to schedule and command the instrument and spacecraft operation during the orbital phase. In this paper we present the architecture of MESSENGER SciBox and its application to pre-orbital simulation and inorbit operational usage.

Mini -RF Orbital Planning and Commanding System

We present an efficient science operations planning and commanding sys tem for the Mini -RF instrument. The Mini -RF instrument is a lightweight side -looking radar system that will use Synthetic Aperture Radar (SAR) to obtain images of the lunar polar regions to search for regions of water -ice deposits. The two missions that wi ll carry the Mini -RF instruments are the Indian Space Research Organisation (ISRO) Chandrayaan -1 lunar orbiter and the NASA Lunar Reconnaissance Orbiter (LRO). The Science Operations Planning and Commanding Subsystems, a suite of planning and commanding to ols, will be used by a small team of scientists to efficiently construct the operations schedule, and to modify any opportunity to maximize the science obtained.

Comprehensive Mission Simulation Contingency Analyses: Achieving Science Observation Plan Resiliency by Design

1 . Automated tools that simulate full orbital dynamics, instrument operation, and data acquisition as well as operational and resource constraints allow planners to develop schedules that are conflict free and fit within mission capabilities. Moreover, if the simulations have sufficient fidelity and are performed well enough in advance, they can also be used to identify and assess risks by analyzing the schedule for sensitivities to different contingencies. In this paper, we discuss a primary risk area for MESSENGER, available solid-state recorder (SSR) space, and describe how we used the tools in MESSENGER SciBox to model the instrument suite data generation, downlink telemetry volume, and the resulting SSR loading through the mission. We then discuss two examples to illustrate how this tool is used to design instrument operations and to analyze the impact of non- nominal downlink performance to specify required contingency responses using a combination of telemetry bandwidth increases and data decimation. Given this simulation and analysis, knowledge of the greatest risks and detailed plans for responses are already in place, providing greater assurance of mission success.

Miniaturized Radar, Outsized Results

The Mini-RF instrument is a Synthetic Aperture Radar that was awarded “technology demonstration” status onboard NASA’s Lunar Reconnaissance Orbiter (LRO). Mini-RF has a sister instrument called Mini-SAR that flew on the Chandrayaan-1 spacecraft for the Indian Space Research Organisation (ISRO). The instruments share a Payload Operations Center (POC) located at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. The LRO instrument has proved to be extremely useful and the stakeholders desire higher use than was originally planned. In fact, the expected data volume for the primary LRO mission increased three hundred-fold from 200 GB to 60 TB. The capabilities of the Mini-RF instrument and POC were increased without burdening the LRO Mission Operations Center (MOC) and personnel. The approach included enacting numerous intermediate manual workarounds with automated solutions following as time and staffing allowed. The Mini-RF team scaled the POC systems to meet the increased demands, enabling Mini-RF to support opportunity targeting and to map large portions of the Moon at both the polar and equatorial regions.

In-vivo measurement of brain edema with the magnetic bio-impedance method

A noninvasive electromagnetic method has been examined that can effectively measure the rapid onset of vasogenic brain edema. Electrical conductivity of normal and edematous brain tissue obtained by this method at frequencies between 1 and 10 MHz is consistent with values obtained with invasive conductivity probes.

Miniature radar operations challenges

Mini-RF consists of two Synthetic Aperture Radar (SAR) instruments that have both acquired data of the lunar surface. One instrument, referred to as Mini-RF, is currently orbiting the Moon onboard the Lunar Reconnaissance Orbiter (LRO) spacecraft.12 A sister instrument, called Mini-SAR, flew on the Chandrayaan-1 spacecraft for the Indian Space Research Organisation (ISRO). The instruments share a Payload Operations Center (POC) located at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.