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HYDRAFloods Near Real-Time Mapping of Flood Events Using Multiple Satellite Sensors
No full textInformation about inundated areas is critical for distributing aid and resources in flood emergency response operations. Conventional methods of monitoring floods, like gauge based observations and reports from local authorities, provide very detailed and accurate information about flood depth and location. However, the geographic coverage of these point-based observations is limited and delays are common. Satellite-based images can help address these challenges, providing near real-time flood extent information over large areas of coverage. The Hydrological Remote Sensing Analysis of Floods (HYDRAFloods) tool, currently being developed by SERVIR-Mekong in collaboration with the Myanmar Department of Disaster Management, is one such example. Generating flood maps, even from satellite imagery, is challenging, given the many disparate sources of information. HYDRAFloods leverages the most recently available remotely sensed data acquired by multiple satellite platforms to automate the creation of daily flood maps. Through combining multiple satellite sources, including optical, microwave, and synthetic aperture radar datasets, near real-time flood maps with reduced cloud impact and increased satellite observations can be generated for use by disaster managers
LRI Improvements from LISA
No full textThis presentation is about a laser development effort for LISA at GSFC. Especially, the micro non-planar ring oscillator and its applicability to future gravitational missions are discussed
NASA's Earth Observing Data and Information System (EOSDIS)
No full textNASA's Earth Observing System Data and Information System (EOSDIS) has been a central component of the NASA Earth observation program since the 1990's. The data collected by NASA represent a significant public investment in research. Consequently, NASA developed a free, open and non-discriminatory policy consistent with existing international policies to maximize access to data. EOSDIS manages data covering a wide range of Earth science disciplines including cryosphere, land cover change, polar processes, field campaigns, ocean surface, geodesy, atmosphere dynamics and composition, and inter-disciplinary research, and many others. This presentation will discuss data stewardship and archive activities
Failure of Nd:YVO4 Amplifier Crystals
No full textBrittle single crystals are used in NASA applications ranging from lenses to centrally heated laser slabs. Despite standard procedures to design such components, unexpected failures occasionally occur. The ICEsat-2 (Ices,Cloud, and Elevation satellite-2) employs Yttrium orthovanadate single crystals in laser amplifiers and oscillators. Although the systems are currently flying and successfully operating, some unexpected crystal fractures occurred just prior to flight. The failures were traced to poor crystal quality along with time-dependent chemical reaction within the system assembly that increased stress beyond expectations and promoted both fast fracture and stress corrosion. This presentation will discuss failure analysis of the crystals and the chemical reactions that promoted failures, along with corrective actions taken to reduce likelihood of fracture over the three-year mission. Re-designed lasers were stored for 12 months and operated for a total of 1,000 hours without signs of degradation
Stress Intensity Factors for Layered Pressure Vessel Inner Layer Through Cracks
No full textA difficulty encountered when performing Fitness-for- Service assessments for layered pressure vessels (LPVs) is the lack of stress intensity factor solution in literature that produce accurate results for inner layer longitudinal through cracks. Using surrogate solutions such as a through crack in a plate or cylinder produce results that can be overly conservative especially for longer cracks. This is largely due to the ability of a layered pressure vessel to redistribute hoop load to other layers, the restricted radial movement of the cracked layer, and the friction forces applied in the cracked region. To understand this problem, a parametric finite element model (FEM) generator was developed that is capable of producing layered pressure vessel models with inner layer through cracks. The results from the FEMs were used to create a dataset of inner layer through crack stress intensity factors (KI) for layered pressure vessels corresponding to variations of internal pressure, radius, layer thicknesses, friction factor, and crack length. The elastic modulus of the material also has an effect on KI but, for this dataset, the elastic modulus was fixed at the typical value for steel - 29,500 ksi (203 GPa). Finally, a non-dimensional model was developed and calibrated using the dataset. This allows KI to be calculated without the need of a FEM using a closed-form equation. The results of the closed-form solution were then compared to FEM results showing accuracy was generally within 10%
A Discussion of the Need to Sustain Mission Ready TPS and for Continued Development of Innovative Entry System Technologies
No full textFlight proven entry system and TPS technologies are critical for the successful execution of in-situ science missions at Venus. Emerging new technologies point to new possibilities and offer innovative approaches to delivering small satellites for orbital science. Venus entry can be very demanding and there are only a few flight proven TPS, some developed by Industry and others by NASA, capable of meeting the mission needs. NASA developed TPS has predominately been transferred to Industry and it is assumed industry will maintain the fabrication capability. However, lack of mission needs may result in obsolence of TSP fabrication capability if there is no money and no motivation. Even within NASA, its' expertise could be diverted to higher priority objectives and thereby the readiness for particular material systems can be impacted or lost. Atrophy of capabilities can come about in other ways as well such as changes to raw materials. Even small manufacturing process changes can demand requalification and TRL may be degraded. Carbon-Phenolic is a text book example. After a long period of absence of US Venus missions, VEXG and the Science community is making the case for future missions. It is insufficient to assume the TSP technologies will be there in 5 or 10 years without active and continual planning and assessment. After Galileo, Carbon-Phenolic materials and fabrication skills were allowed to atrophy. Then when missions needed it, in early 2000, it was no longer possible to make the heritage Carbon-Phenolic. What do we need to do? The first step is to advocate for the establishment of TPS readiness assess-ment. The assessment will involve understanding threats and opportunities, and the development of risk mitigation strategies. VEXAG needs to advocate for such an active monitoring of the needed capabilities, assessment of emerging risks and development of risk mitigation strategies with implementation plans. Such an approach reduces the threat of material obsolence and helps maintain the availability of entry system and TPS technology capabilities, both old and new. Venus probes, landers, balloons and other variable altitude missions, and skimmer missions such as "Cu-pid's Arrow" as well as aerocapture missions to deliver small spacecraft require qualified entry systems and ablative TPS. VEXAG advocated for HEEET in 2013/2014 and the community is well versed with the need to sustain it. But, other TPS that need to be sustained may not be apparent to VEXAG community. The following figure summarizes the ablative TPS capabilities vs Venus mission needs for both primary heatshield and backshell
Flight Performance Maneuver Planning for NASAs X-57 Maxwell Flight Demonstrator Part 1: Power-Off Glides
No full textDistributed Electric Propulsion technology is expected to yield up to a fivefold increase in
high-speed cruise efficiency for NASAs X-57 Maxwell flight demonstrator when compared
to a combustion-powered general aviation baseline. A portion of this increased efficiency is
due to beneficial aero-propulsive interaction inherent to the distributed propulsion
architecture. The measure of the relative increase in efficiency between a conventional and
distributed propulsion wing will be extracted from comparisons between flight test data from
the electrically powered X-57 Mod II configuration with a conventional wing, and from the
electrically powered X-57 Mod III/IV configuration with a distributed propulsion wing. Flight
test maneuvers that accommodate errors in instrumentation and the flight test environment
are developed to establish the power-off drag characteristics for all X-57 configurations.
Analysis of these maneuvers with typical errors, including pilot-in-the-loop simulation data
that incorporates simulated atmospheric turbulence effects, shows that the proposed power-off
flight maneuvers can generate accurate power-off drag predictions for the X-57. These
predictions show that the power-off differences in aerodynamic performance between the
conventional and distributed propulsion configurations can be accurately measured from
flight test data in the presence of typical data error sources