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Topic Review
Television Infrared Observation Satellite
TIROS, or Television InfraRed Observation Satellite, is a series of early weather satellites launched by the United States , beginning with TIROS-1 in 1960. TIROS was the first satellite that was capable of remote sensing of the Earth, enabling scientists to view the Earth from a new perspective: space. The program, promoted by Harry Wexler, proved the usefulness of satellite weather observation, at a time when military reconnaissance satellites were secretly in development or use. TIROS demonstrated at that time that "the key to genius is often simplicity". TIROS is an acronym of "Television InfraRed Observation Satellite" and is also the plural of "tiro" which means "a young soldier, a beginner". Participants in the TIROS project included the National Aeronautics and Space Administration (NASA), United States Army Signal Research and Development Laboratory, Radio Corporation of America (RCA), the United States Weather Bureau Service, the United States Naval Photographic Interpretation Center (NPIC), the Environmental Science Services Administration (ESSA), and the National Oceanic and Atmospheric Administration (NOAA).
  • 1.5K
  • 04 Nov 2022
Topic Review
GRACE and GRACE-FO
The Gravity Recovery and Climate Experiment (GRACE) was a joint mission of NASA and the German Aerospace Center (DLR). Twin satellites took detailed measurements of Earth's gravity field anomalies from its launch in March 2002 to the end of its science mission in October 2017. The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) is a continuation of the mission on near-identical hardware, launched in May 2018. By measuring gravity anomalies, GRACE showed how mass is distributed around the planet and how it varies over time. Data from the GRACE satellites is an important tool for studying Earth's ocean, geology, and climate. GRACE was a collaborative endeavor involving the Center for Space Research at the University of Texas at Austin, NASA's Jet Propulsion Laboratory, the German Aerospace Center and Germany's National Research Center for Geosciences, Potsdam. The Jet Propulsion Laboratory was responsible for the overall mission management under the NASA ESSP (Earth System Science Pathfinder) program. The principal investigator is Byron Tapley of the University of Texas Center for Space Research, and the co-principal investigator is Christoph Reigber of the GeoForschungsZentrum (GFZ) Potsdam. The two GRACE satellites (GRACE-1 and GRACE-2) were launched from Plesetsk Cosmodrome, Russia, on a Rockot (SS-19 + Breeze upper stage) launch vehicle on 17 March 2002. The spacecraft were launched to an initial altitude of approximately 500 km at a near-polar inclination of 89°. During normal operations, the satellites were separated by 220 km along their orbit track. This system was able to gather global coverage every 30 days. GRACE far exceeded its 5-year design lifespan, operating for 15 years until the decommissioning of GRACE-2 on 27 October 2017. Its successor, GRACE-FO, was successfully launched on 22 May 2018. In 2019, a glacier in West Antarctica was named after the GRACE mission.
  • 1.5K
  • 23 Nov 2022
Topic Review
GRACE-FO
The Gravity Recovery and Climate Experiment (GRACE) was a joint mission of NASA and the German Aerospace Center (DLR). Twin satellites took detailed measurements of Earth's gravity field anomalies from its launch in March 2002 to the end of its science mission in October 2017. The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) is a continuation of the mission on near-identical hardware, launched in May 2018. By measuring gravity anomalies, GRACE showed how mass is distributed around the planet and how it varies over time. Data from the GRACE satellites is an important tool for studying Earth's ocean, geology, and climate. GRACE was a collaborative endeavor involving the Center for Space Research at the University of Texas at Austin, NASA's Jet Propulsion Laboratory, the German Aerospace Center and Germany's National Research Center for Geosciences, Potsdam. The Jet Propulsion Laboratory was responsible for the overall mission management under the NASA ESSP (Earth System Science Pathfinder) program. The principal investigator is Byron Tapley of the University of Texas Center for Space Research, and the co-principal investigator is Christoph Reigber of the GeoForschungsZentrum (GFZ) Potsdam. The two GRACE satellites (GRACE-1 and GRACE-2) were launched from Plesetsk Cosmodrome, Russia, on a Rockot (SS-19 + Breeze upper stage) launch vehicle on 17 March 2002. The spacecraft were launched to an initial altitude of approximately 500 km at a near-polar inclination of 89°. During normal operations, the satellites were separated by 220 km along their orbit track. This system was able to gather global coverage every 30 days. GRACE far exceeded its 5-year design lifespan, operating for 15 years until the decommissioning of GRACE-2 on 27 October 2017. Its successor, GRACE-FO, was successfully launched on 22 May 2018. In 2019, a glacier in West Antarctica was named after the GRACE mission.
  • 1.5K
  • 07 Nov 2022
Topic Review
Boeing F-15SE Silent Eagle
The Boeing F-15SE Silent Eagle was a proposed upgrade of the F-15E strike fighter by Boeing using stealth features, such as internal weapons carriage and radar-absorbent material.
  • 1.4K
  • 21 Oct 2022
Topic Review
List of Ariane Launches (2010–2019)
This is a list of launches performed or scheduled to be performed by Ariane carrier rockets between 2010 and 2019. Since 2004, only the Ariane 5 is in service, operating in the ECA and ES configurations.
  • 1.4K
  • 08 Oct 2022
Topic Review
3D Printed Nonlinear Musculoskeletal Actuator
A nature-inspired musculoskeletal-actuator system is developed using 3d printing for robotic applications. The actuator resembles the rigid segments and the soft-rigid interaction architecture found in limbless vertebrates such as snakes. The rigid segments provide an increase in the range of motion while maintaining structural durability and stability. The soft-rigid interactions provided a remarkable increase in energy transmission and storage, which enhanced the reliability of the musculoskeletal-actuator. Additionally, passive structural stiffness and damping control are achieved. Similar to a muscular system, our musculoskeletal-actuator is capable of increasing its stiffness and damping up to 100% and 60%, respectively, upon load lifting.
  • 1.4K
  • 28 Mar 2022
Topic Review
NanoRacks CubeSat Deployer
The NanoRacks CubeSat Deployer (NRCSD) is a device to deploy CubeSats into orbit from the International Space Station. Currently, there are two CubeSat deployers on board the International Space Station (ISS): The Japanese Experiment Module (JEM) Small Satellite Orbital Deployer (J-SSOD) and the NanoRacks CubeSat Deployer (NRCSD). The J-SSOD is the first of its kind to deploy small satellites from the International Space Station. The NRCSD is the first commercially operated small satellite deployer from the ISS, maximizing full capabilities of each airlock cycle of deployments. CubeSats belong to a class of research spacecraft called nanosatellites. The basic cube-shaped satellites measure 10 centimeters (3.9 in) on each side, weigh less than 3 pounds (1.4 kg), and have a volume of about 1 liter (0.22 imp gal; 0.26 U.S. gal), although there are CubeSats which are built and deployed with sizes of multiples of 10 cm in length. (As of 2014), one method of getting CubeSats to orbit is to transport them aboard a larger spacecraft as part of a cargo load to a larger space station. When this is done, deploying the CubeSats into orbit as a separate artificial satellite requires a special apparatus, such as the NanoRacks CubeSat Deployer. The NRCSD is put into position to be grabbed by one of the ISS's robotic arms, which then places the CubeSat deployer into the correct position externally mounted to the ISS to be able to release the miniature satellites into proper orbit.
  • 1.4K
  • 14 Nov 2022
Topic Review
Journal Acoustics
Acoustics (ISSN 2624-599X) is a peer-reviewed, open access journal of acoustics science and engineering published quarterly online by MDPI. It is indexed by the Emerging Sources Citation Index (ESCI) in Web of Science. Manuscripts are peer-reviewed and a first decision provided to authors approximately 11.7 days after submission; acceptance to publication is undertaken in 2.9 days (median values for papers published in this journal in the second half of 2020).
  • 1.4K
  • 26 Sep 2021
Topic Review
Resilient UAV Swarms
UAVs have rapidly become prevalent in applications related to surveillance, military operations, and disaster relief. Their low cost, operational flexibility, and unmanned capabilities make them ideal for accomplishing tasks in areas deemed dangerous for humans to enter. They can also accomplish previous high-cost and labor-intensive tasks, such as land surveying, in a faster and cheaper manner. Researchers studying UAV applications have realized that a swarm of UAVs working collaboratively on tasks can achieve better results. The dynamic work environment of UAVs makes controlling the vehicles a challenge. 
  • 1.4K
  • 04 May 2023
Biography
Robert L. Behnken
Robert Louis "Bob" Behnken (born July 28, 1970 in Creve Coeur, Missouri) is a United States Air Force officer, NASA astronaut and former Chief of the Astronaut Office. Behnken holds a Ph.D in Mechanical Engineering and holds the rank of Colonel in the U.S. Air Force. Col. Behnken has logged over 1,000 flight hours in 25 different aircraft. He flew aboard Space Shuttle missions STS-123 and STS-13
  • 1.3K
  • 21 Nov 2022
Topic Review
MSU Temperature Measurements
Microwave sounding unit temperature measurements have been obtained from the troposphere since 1979, when they were included within NOAA weather satellites. By comparison, the usable balloon (radiosonde) record begins in 1958 but has less geographic coverage and is less uniform. Satellites do not measure temperature. They measure radiances in various wavelength bands, which must then be mathematically inverted to obtain indirect inferences of temperature. The resulting temperature profiles depend on details of the methods that are used to obtain temperatures from radiances. As a result, different groups that have analyzed the satellite data have obtained different temperature trends. Among these groups are Remote Sensing Systems (RSS) and the University of Alabama in Huntsville (UAH). The satellite series is not fully homogeneous - the record is constructed from a series of satellites with similar but not identical instrumentation. The sensors deteriorate over time, and corrections are necessary for satellite drift in orbit. Particularly large differences between reconstructed temperature series occur at the few times when there is little temporal overlap between successive satellites, making intercalibration difficult. To compare to the trend from the surface temperature record (approximately +0.07 °C/decade over the past century and +0.15-0.16 °C/decade since 1979) it is most appropriate to derive trends for the part of the atmosphere nearest the surface, i.e., the lower troposphere. Doing this, through January 2012: An alternative adjustment introduced by Fu et al. (2004) finds trends (1979–2011) of +0.14 °C/decade when applied to the RSS data set and +0.11 °C/decade when applied to the UAH data set . Using the T2 channel (which include significant contributions from the stratosphere, which has cooled), Mears et al. of Remote Sensing Systems (RSS) find (through January 2012) a trend of +0.082 °C/decade. Spencer and Christy of the University of Alabama in Huntsville (UAH), find a smaller trend of +0.046 °C/decade. A no longer updated analysis of Vinnikov and Grody found +0.20 °C/decade (1978–2005). Another satellite temperature analysis is provided by NOAA/NESDIS STAR Center for Satellite Application and Research and use simultaneous nadir overpasses (SNO) to remove satellite intercalibration biases yielding more accurate temperature trends. The SNO analysis finds a 1979-2011 trend of +0.128 °C/decade for T2 channel. The satellite records have the advantage of greater spatial coverage, whereas the radiosonde record is longer. There have been complaints of data problems with both records, and difficulty reconciling climate model predictions with the observed data.
  • 1.3K
  • 09 Oct 2022
Topic Review
Lightning Strike Damage Assessments of Composites
Lightning strike events pose significant challenges to the structural integrity and performance of composite materials, particularly in aerospace, wind turbine blade, and infrastructure applications. 
  • 1.3K
  • 07 Feb 2024
Topic Review
AVIC UAVs
AVIC UAVs are Chinese UAVs developed by Aviation Industry Corporation of China (AVIC), some of which has entered service with Chinese military.
  • 1.3K
  • 02 Dec 2022
Topic Review
Nondestructive Testing Methods
Material failure may occur in a variety of situations dependent on stress conditions, temperature, and internal or external load conditions. Many of the latest engineered materials combine several material types i.e., metals, carbon, glass, resins, adhesives, heterogeneous and nanomaterials (organic/inorganic) to produce multilayered, multifaceted structures that may fail in ductile, brittle, or both cases.
  • 1.3K
  • 08 Oct 2021
Topic Review
List of Thor and Delta Launches (2010–19)
As of October 2018, only the Delta IV remains in production. Single-stick versions of Delta IV was retired in 2019 and replaced by Atlas V, leaving the Delta IV Heavy the only remaining operational member of the Delta family, flying defense missions.
  • 1.3K
  • 21 Nov 2022
Topic Review
Low Earth Orbit Space Missions Power Bus Management
In space vehicles, the typical configurations for the Solar Array Power Regulators in charge of managing power transfer from the solar array to the power bus are quite different from the corresponding devices in use for terrestrial applications. Since the 1970s the most widely used approach for spacecraft power conditioning has been Sequential Switching Shunt Regulation (S3R), because of its high power density, modularity, simplicity, and inherently high reliability. Power regulation schemes implementing Maximum Power Point Tracking (MPPT) techniques have been introduced since the 1990s. At the expense of a larger complexity, they provide optimal energy harvesting in a wide range of operating conditions. In sectional MPPT power units, the solar array is split into several sections, each fitted up with a dedicated Solar Array Power Regulator (APR) with a multimode controller, capable of either independently performing MPPT or harmonically contributing to the regulation of the bus voltage or the battery current. An expedient solution appears to be provided by the Sequential Maximum Power Tracking (SMPT) bus regulation technique: the coordination problem is solved by implementing an operational sequence such that just one section at a time is kept in control mode, while the others are kept either in MPPT or in standby.
  • 1.3K
  • 06 Dec 2021
Topic Review
Machine Learning in Aviation Environmental Impact Analysis
The rapid growth of global aviation operations has made its negative environmental impact an international concern. Accurate modeling of aircraft fuel burn, emissions, and noise is the prerequisite for informing new operational procedures, technologies, and policies towards a more sustainable future of aviation. Due to the advances in big data technologies and effective algorithms, the transformative data-driven analysis has begun to play a substantial role in aviation environmental impact analysis. The integration of statistical and machine learning methods in the workflow has made such analysis more efficient and accurate.
  • 1.3K
  • 13 Feb 2023
Topic Review
Civil Aviation Occurrences
The nature of a civil aviation occurrence may be defined in three different categories while considering its severity. General categories include civil aviation accidents, serious incidents and incidents.
  • 1.2K
  • 16 Jun 2021
Topic Review
QuikSCAT
The NASA QuikSCAT (Quick Scatterometer) was an Earth observation satellite carrying the SeaWinds scatterometer. Its primary mission was to measure the surface wind speed and direction over the ice-free global oceans. Observations from QuikSCAT had a wide array of applications, and contributed to climatological studies, weather forecasting, meteorology, oceanographic research, marine safety, commercial fishing, tracking large icebergs, and studies of land and sea ice, among others. This SeaWinds scatterometer is referred to as the QuikSCAT scatterometer to distinguish it from the nearly identical SeaWinds scatterometer flown on the ADEOS-2 satellite.
  • 1.2K
  • 01 Nov 2022
Topic Review
Additive Manufacturing Technology for Metal Mirrors
With the rapid growth of space optics and aerospace technology, the applications of reflective optical systems are increasing year by year. A case in point is that off-axis three-mirror-anastigmat (TMA) systems have been widely used due to their unique advantages of large aperture and no central occlusion. Meanwhile, the growing requirements for optical systems’ performance, such as resolution and imaging quality, drive the development of focal length and aperture to larger sizes. In turn, the weight, surface accuracy, manufacturing time, and mirror cost are progressively demanding. In recent years, the lightweight space camera used for remote sensing with high resolution has become a global research hotspot in advanced optics.
  • 1.2K
  • 24 Nov 2021
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