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Topic Review
Minimum Quantity Lubrication Machining of Titanium Alloys
Titanium alloys offer a variety of unique qualities, including high strength, resistance to chemical deterioration, and excellent corrosion resistance, particularly stress corrosion. These alloys are utilized in aircraft, power plants, heat exchangers, water heaters, pressure vessels, and orthopedic implants because of their characteristics. Minimum quantity lubrication (MQL) is one method in which just a small amount of fluid is required during machining operations.
  • 1.7K
  • 02 Sep 2022
Topic Review
Evolved Expendable Launch Vehicle
Evolved Expendable Launch Vehicle (EELV) is an expendable launch system program of the United States Air Force (USAF), intended to assure access to space for Department of Defense and other United States government payloads. The program, which began in the 1990s with the goal of making government space launches more affordable and reliable, resulted in the development of the Delta IV and Atlas V. Along with the newer Falcon 9, these launch systems are the primary methods for launching U.S. military satellites. The USAF plans to use the EELV family of launch vehicles until at least 2030. Follow-on technologies are being considered, one of which was the Reusable Booster System, discontinued in 2012.
  • 1.7K
  • 14 Oct 2022
Topic Review
Balloon Satellite
A balloon satellite (also occasionally referred to as a "satelloon", which is a trademarked name owned by Gilmore Schjeldahl's G.T. Schjeldahl Company) is a satellite that is inflated with gas after it has been put into orbit.
  • 1.6K
  • 17 Oct 2022
Topic Review
Physics of Riblets
Continuous evolution in nature has created optimum solutions for creature survival that have inspired many innovative engineering designs. Riblet geometries, passive flow control devices, have been studied, which were inspired by the skin of fast-swimming sharks. Turbulent boundary layer research reveals the positive effect of riblets in reducing drag by manipulating turbulent structures. 
  • 1.6K
  • 23 Oct 2023
Topic Review
List of H-II and H3 Launches
This is a list of launches made by JAXA using H-II, H-IIA, H-IIB and H3 rockets.
  • 1.6K
  • 21 Nov 2022
Topic Review
Gravity Field and Steady-State Ocean Circulation Explorer
The Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) was the first of ESA's Living Planet Programme satellites intended to map in unprecedented detail the Earth's gravity field. The spacecraft's primary instrumentation was a highly sensitive gravity gradiometer consisting of three pairs of accelerometers which measured gravitational gradients along three orthogonal axes. Launched on 17 March 2009, GOCE mapped the deep structure of the Earth's mantle and probed hazardous volcanic regions. It brought new insight into ocean behaviour; this in particular, was a major driver for the mission. By combining the gravity data with information about sea surface height gathered by other satellite altimeters, scientists were able to track the direction and speed of geostrophic ocean currents. The low orbit and high accuracy of the system greatly improved the known accuracy and spatial resolution of the geoid (the theoretical surface of equal gravitational potential on the Earth). The satellite's unique arrow shape and fins helped keep GOCE stable as it flew through the thermosphere at a comparatively low altitude of 255 kilometres (158 mi). Additionally, an ion propulsion system continuously compensated for the variable deceleration due to air drag without the vibration of a conventional chemically powered rocket engine, thus limiting the errors in gravity gradient measurements caused by non-gravitational forces and restoring the path of the craft as closely as possible to a purely inertial trajectory. After running out of propellant, the satellite began dropping out of orbit and made an uncontrolled reentry on 11 November 2013.
  • 1.6K
  • 02 Nov 2022
Topic Review
Shuttle-Derived Launch Vehicle
Shuttle-Derived Launch Vehicle (SDLV), or simply Shuttle-Derived Vehicle (SDV), is a term describing one of an array of concepts that have been developed for building space launch vehicles using the already developed components, technology, and infrastructure of the Space Shuttle program. In the late 1980s and early 1990s, NASA formally studied a cargo-only vehicle, Shuttle-C, that would have supplemented the crewed Space Shuttle. In 2005, NASA was developing the Ares I and Ares V launch vehicles, based in part on highly modified Shuttle components, to enable exploration of the Moon and Mars. The agency also studied a third such vehicle, the Ares IV.
  • 1.6K
  • 29 Nov 2022
Topic Review
Non-Destructive Evaluation of Structural Composite Materials
The growing demand and diversity in the application of industrial composites and the current inability of present non-destructive evaluation (NDE) methods to perform detailed inspection of these composites has motivated this comprehensive review of sensing technologies. NDE has the potential to be a versatile tool for maintaining composite structures deployed in hazardous and inaccessible areas, such as offshore wind farms and nuclear power plants. Therefore, the future composite solutions need to take into consideration the niche requirements of these high-value/critical applications. Composite materials are intrinsically complex due to their anisotropic and non-homogeneous characteristics. This presents a significant challenge for evaluation and the associated data analysis for NDEs. For example, the quality assurance, certification of composite structures, and early detection of the failure is complex due to the variability and tolerances involved in the composite manufacturing. Adapting existing NDE methods to detect and locate the defects at multiple length scales in the complex materials represents a significant challenge, resulting in a delayed and incorrect diagnosis of the structural health. This paper presents a comprehensive review of the NDE techniques, that includes a detailed discussion of their working principles, setup, advantages, limitations, and usage level for the structural composites. A comparison between these techniques is also presented, providing an insight into the future trends for composites’ prognostic and health management (PHM). Current research trends show the emergence of the non-contact-type NDE (including digital image correlation, infrared tomography, as well as disruptive frequency-modulated continuous wave techniques) for structural composites, and the reasons for their choice over the most popular contact-type (ultrasonic, acoustic, and piezoelectric testing) NDE methods is also discussed. The analysis of this new sensing modality for composites’ is presented within the context of the state-of-the-art and projected future requirements.
  • 1.6K
  • 20 Dec 2021
Topic Review
Signal Processing of Pulsed Thermography for Enhanced Detectability
Non-destructive testing (NDT) is a broad group of testing and analysis techniques used in science and industry to evaluate the properties of a material, structure, or system for characteristic defects and discontinuities without causing damage. Recently, infrared thermography is one of the most promising technologies as it can inspect a large area quickly using a non-contact and non-destructive method. Moreover, thermography testing has proved to be a valuable approach for non-destructive testing and evaluation of structural stability of materials. Pulsed thermography is one of the active thermography technologies that utilizes external energy heating. However, due to the non-uniform heating, lateral heat diffusion, environmental noise, and limited parameters of the thermal imaging system, there are some difficulties in detecting and characterizing defects.
  • 1.6K
  • 17 Jan 2022
Topic Review
Aeroengines’ Bolt Preload Formation Mechanism and Control Technology
The bolt connection structure is widely used in the connection of aeroengine parts, and its connection quality is very important, as it can directly affect the geometric and dynamic performance of the aeroengine. This entry conducts a detailed summary of the aeroengine bolt connection research, in terms of both the tightening mechanism and control technology of bolt connection. It offers a comprehensive review including the tightening mechanism of the single bolt and group bolts, bolt tightening process, and bolt tightening equipment. Besides, the relationship between the tightening mechanism and control technology is summarized. Finally, the future research direction of aeroengine bolt connection through the digital twin is proposed.
  • 1.6K
  • 20 Jul 2023
Topic Review
Spoken ATC Instruction Understanding
Spoken ATC Instruction Understanding means in air traffic control, speech communication with radio transmission is the primary way to exchange information between the controller and aircrew. A wealth of contextual situational dynamics is embedded implicitly; thus, understanding the spoken instruction is particularly significant to the ATC research. ATC is a complicated and time-varying system, in which operational safety is always a hot research topic. All achievements of an ATC center can be vetoed without any hesitation if any safety incident occurs. Air traffic safety is affected by various aspects of air traffic operation, from mechanical maintenance, resource management, to air traffic control. The safety of air traffic control is particularly important since the aircraft is already in the air. There is no doubt that any effort deserves to be made to improve ATC safety.
  • 1.6K
  • 06 Apr 2021
Topic Review
DAVINCI+
DAVINCI+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging, Plus) is a planned mission for an orbiter and atmospheric probe to the planet Venus. Together with the VERITAS mission, which will also study Venus, it was selected by NASA on 2 June 2021 to be part of their Discovery Program. DAVINCI+ will send both an orbiter and a descent probe to Venus. The orbiter will image Venus in multiple wavelengths from above, while the descent probe will study the chemical composition of Venus' atmosphere and take photographs during descent. The DAVINCI+ probe will travel through the Venusian atmosphere, sampling the atmosphere, and returning measurements down to the surface. These measurements are important to understanding the origin of the atmosphere, how it has evolved, and how and why it is different from the atmosphere of Earth and Mars. The measurements taken by DAVINCI+ will investigate the possible history of water on Venus and the chemical processes at work in the unexplored lower atmosphere. Before it reaches the surface, the DAVINCI+ probe will capture high resolution images of the planet's ridged terrain ("tesserae"), returning the first images of the planet's surface since Soviet Venera 13 lander in 1981. It will also collect data for studying the planet's origin, and its tectonic and weathering history.
  • 1.6K
  • 17 Oct 2022
Topic Review
Saturn V Dynamic Test Vehicle
Saturn V Dynamic Test Vehicle, designated SA-500D, is a prototype Saturn V rocket used by NASA to test the performance of the rocket when vibrated to simulate the shaking which subsequent rockets would experience during launch. It was the first full-scale Saturn V completed by the Marshall Space Flight Center (MSFC). Though SA-500D never flew, it was instrumental in the development of the Saturn V rocket which propelled the first men to the Moon as part of the Apollo program. Built under the direction of Dr. Wernher von Braun, it served as the test vehicle for all of the Saturn support facilities at MSFC. SA-500D is the only Saturn V on display that was used for its intended purpose, and the only one to have been assembled prior to museum display. It is on permanent display at the U.S. Space & Rocket Center, Huntsville, Alabama.
  • 1.5K
  • 17 Oct 2022
Topic Review
Shavit
Shavit (Hebrew: "comet" – שביט) is a small lift launch vehicle produced by Israel from 1982 onwards, to launch satellites into orbit. It was first launched on September 19, 1988 (carrying an Ofeq satellite payload), making Israel the eighth nation to have an orbital launch capability after the USSR, United States , France , Japan , People’s Republic of China, United Kingdom , and India . The Shavit project is believed to have been an offshoot development, resulting from Israel's Jericho nuclear armed intercontinental ballistic missile program. Shavit rockets are launched from Palmachim Airbase by the Israel Space Agency into highly retrograde orbits over the Mediterranean Sea to prevent debris coming down in populated areas and also to avoid flying over nations hostile to Israel to the east; this results in a lower payload-to-orbit than east-directed launches would allow. The launcher consists of three stages powered by solid-fuel rocket motors, with an optional liquid-fuel fourth stage, and is manufactured by IAI. The Republic of South Africa produced and tested a licensed version in cooperation with Israel called the RSA-3 in an ultimately unsuccessful bid to produce a domestic satellite launch vehicle and ballistic missile; the South African program was closed in 1994. An earlier unrelated project called Shavit 2 was the first Israeli sounding rocket, launched on 5 July 1961 for meteorological research. Shavit Three, with an altitude reported as 100 miles, was launched on 11 August 1961.
  • 1.5K
  • 28 Nov 2022
Topic Review
Role of Surface Roughness in Ice Formation
Surface roughness or asperities plays a detrimental role in the icephobicity of a surface. This could be in the form of overall surface roughness or imparting surface features that may aid to mitigate ice anchoring or encourage favourable wettability conditions to induce icephobic performance.
  • 1.5K
  • 18 Jul 2023
Topic Review
Applications of Sustainable Hybrid Energy Harvesting
The potential usage of self-powered wireless sensor (WSN) systems has drawn a lot of attention to sustainable energy harvesting. Hybrid energy harvesting involves collecting energy from multiple sources and converting it into electrical energy using various transduction mechanisms. By properly integrating different energy conversion technologies, hybridization can significantly increase power outputs and improve space utilization efficiency.
  • 1.5K
  • 28 Nov 2023
Topic Review
Passenger Boarding Strategies
Boarding time constitutes a critical element of turnaround time, which is used to measure the efficiency of airline operations. Therefore, to reduce boarding time, it is imperative to reconsider traditional passenger boarding strategies to make them more efficient. Different techniques have been used to address the problem, including the following: (1) simulation, (2) analytical methods, and (3) experiments in the aircraft.
  • 1.5K
  • 11 Feb 2024
Biography
Edward Gibson
Edward George Gibson (born November 8, 1936) is a former NASA astronaut, pilot, engineer, and physicist. Before becoming a NASA astronaut, Gibson graduated from the University of Rochester and the California Institute of Technology. He became a research assistant in jet propulsion while completing his studies and eventually became a research scientist for Philco Corporation until joining NASA.
  • 1.5K
  • 15 Nov 2022
Topic Review
Soyuz TMA-19
Soyuz TMA-19 was a crewed spaceflight to the International Space Station (ISS) and is part of the Soyuz programme. It was launched on 15 June 2010 carrying three members of the Expedition 24 crew to the International Space Station, who remained aboard the station for around six months. Soyuz TMA-19 was the 106th crewed flight of a Soyuz spacecraft, since the first mission which was launched in 1967. The spacecraft remained docked to the space station for the remainder of Expedition 24, and for Expedition 25, to serve as an emergency escape vehicle. It undocked from ISS and landed in Kazakhstan on 26 November 2010. It was the 100th mission to be conducted as part of the International Space Station programme since assembly began in 1998.
  • 1.5K
  • 25 Nov 2022
Topic Review
PTScientists
Planetary Transportation Systems GmbH (PTS), formerly known as PTScientists and Part-Time Scientists, is a Berlin-based aerospace company. They developed the robotic lunar lander "ALINA" and seek to land on the Moon with it. They became the first German team to officially enter the Google Lunar X-Prize competition on June 24, 2009, but failed to reach the finals in 2017 for lack of a launch contract. As of the summer of 2019, their goal is still to land a mission on the Moon. The launch is not expected to happen before 2021, and the company is seeking bankruptcy protection.
  • 1.5K
  • 24 Oct 2022
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