News Article | April 29, 2017
The instrument, named "ShadowCam," will be a U.S. contribution to the Korea Aerospace Research Institute's (KARI) first lunar exploration mission, Korea Pathfinder Lunar Orbiter (KPLO). The ShadowCam optical camera is based on the Lunar Reconnaissance Orbiter Narrow Angle Camera also developed by Mark Robinson and MSSS. It is, however, significantly more sensitive, allowing the camera to obtain high-resolution, high signal-to-noise imaging of the Moon's PSRs. "The telescope and much of the electronics will be identical," says ShadowCam principal investigator Robinson. "The big difference is swapping out the current image sensor for one that is 800 times more sensitive, allowing high resolution imaging within permanently shadowed regions, something the Lunar Reconnaissance Orbiter Camera cannot accomplish." For those familiar with digital cameras, this sensitivity gain is like going from ISO 100 to ISO 80,000. Launching in 2018, ShadowCam will observe PSRs on the Moon monthly to detect seasonal changes as well as measure the terrain inside these enigmatic craters, including the distribution of boulders. Eventually ShadowCam images will be merged with the Lunar Reconnaissance Obiter Narrow Angle Camera (NAC) images to make complete maps of inside and outside of craters that host PSRs. While the NAC provides coverage of illuminated areas, ShadowCam will provide images of the shadowed areas. "These merged maps will put us one step closer to enabling landers and rovers to investigate the mysterious lunar PSRs," says Robinson. ShadowCam will address what NASA calls, "Strategic Knowledge Gaps," or information the agency would like to gather in order to reduce risk, increase effectiveness, and improve the designs of future human and robotic missions in deep space. ShadowCam joins four other instruments on KPLO. KARI, headquartered in Daejeon, South Korea, provided NASA with 15 kg (about 33 pounds) of payload space aboard the KPLO, which is scheduled to launch into lunar orbit in December 2018. ShadowCam was selected as a result of NASA seeking science instruments that could increase our understanding of the distribution of volatiles, such as water, including the movement of such resources toward permanently shadowed regions and how they become trapped there. "Permanently shadowed regions have been a mystery because the perpetually dark interiors are difficult to image and existing research offers varying interpretations regarding the distribution of volatiles within these cold regions," says Jason Crusan, Director of NASA's Advanced Exploration Systems Division at NASA Headquarters in Washington DC. "Future missions in deep space will be safer and more affordable if we have the capability to harvest lunar resources, and ShadowCam has the potential to greatly increase our understanding of the quality and abundance of those resources in these regions." Robinson and his team, including ShadowCam's deputy principal investigator Prasun Mahanti and co-investigator Nicholas Estes, plan to run joint operations with ShadowCam and LROC from ASU's Tempe campus. "There is much synergy having the experiments run jointly both in terms of operational efficiency and science return," says Robinson. NASA's Advanced Exploration Systems Division (AES) led the payload solicitation and selection for the NASA instrument on KPLO. A division of the Human Exploration and Operations Mission Directorate, AES uses innovative approaches and public-private partnerships to rapidly develop prototype systems, advance key capabilities, and validate operational concepts for future human missions beyond Earth orbit. Through this partnership opportunity with KARI, AES is addressing key lunar SKGs while complementing KARI's primary mission objectives and instruments. Explore further: Scientist to Work With NASA's Lunar Orbiter
Kim S.,Pohang University of Science and Technology |
Choi C.,KARI |
Kim J.,KARI |
Park J.,KIMM |
Baek J.,Pohang University of Science and Technology
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy | Year: 2013
The objectives of the present study were to investigate the effects of tip clearance on the performance and flow characteristics of a turbopump inducer by using computational fluid dynamics. Three different tip-clearance sizes were analyzed for design and off-design conditions. The numerical results were validated by comparison with experimental results. Our detailed investigation of the simulated flow fields shows that backflow penetrates farther upstream for large-tip clearances, which means that performance declines rapidly. On the other hand, for small-tip clearances, the extent of backflow is reduced but the development of hub separation in the middle of the passage causes performance degradation. Our results confirm that a particular value of the tip-clearance limits the development of secondary flow in the passage. © IMechE 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
Cho D.-H.,KARI |
Bang H.,KAIST |
Proceedings of the International Astronautical Congress, IAC | Year: 2013
There are many kinds of strategies for the optimal lunar landing trajectory design. This lunar landing stage is usually divided into two parts, de-orbit burn phase and powered descent phase, and the optimal lunar landing problem is focused on the powered descent phase by using continuous thruster. These optimal lunar landing trajectories have a variety shape and the lunar lander frequently increased its altitude at the initial time to earn the enough time to reduce the horizontal velocity. Due to this increase, the lunar lander requires more fuel for lunar landing mission. This phenomenon is depending on its thrust-mass ratio. For the enough thrust, this increase in the altitude is reduced, but this huge thrust-mass ratio is sometimes not physically possible due to the cost, mass budget, thruster technology and so on. Therefore, we suggest the hybrid engine for the lunar landing mission and we also introduce the optimal lunar landing strategy for this engine. For this approach, we supposed that the lunar lander retro fired the impulsive thruster to rapidly reduce the horizontal velocity at the initiated time of the powered descent phase. Then the lander reduced the total velocity and altitude for the lunar landing by using continuous thruster. In contradistinction to other formal optimal lunar landing problem, the initial horizontal velocity and mass are not fixed at the start time due to the retrofiring maneuver in this problem. Thus, the initial free optimal control theory is applied in this paper and we can find out the optimal initial value and optimal lunar landing trajectory to minimize the fuel consumption.
Baek S.-H.,KAIST |
Kim W.-S.,KARI |
Jang C.-J.,KAIST |
Key Engineering Materials | Year: 2011
For most of structural failure in engineering structures, fracture often takes place due to a phenomenon called fatigue. Therefore, many studies about the effect of the various mode-mixities on fatigue characteristics have been performed. However, most of the former studies are about metal/metal interface or delamination of composite. In this study, the fatigue characteristics of a composite/metal interface are investigated. The fatigue tests were performed using single-leg bending (SLB) specimens bonded with composite and steel using co-cure bonding method. This paper focuses on the fatigue characteristics depending on different mode ratios (GΠ/GT). The overall results obtained in this study show that the crack propagation rate increases with the mode Π loading component.
Cho D.-H.,KARI |
Lee D.,KARI |
Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering | Year: 2016
In the optimal trajectory design problem for the lunar powered-descent phase, the periapsis of the de-orbit burn phase is usually chosen as a starting point or an initial state. The resultant trajectory in these cases shows that the altitude of the lander increases to gain more sufficient time to reduce large initial horizontal velocity. However, the periapsis of the de-orbit burn phase is not the optimal choice. In this study, the optimal initial phase angle can be found by applying the modified trajectory-optimization problem, where the initial state is considered as a free variable. In this problem, any additional assumption and change in hardware compared with the traditional optimal lunar-landing problem are not imposed except for the initial phase angle. Using the proposed numerical approach, we show that the optimal phase angle is not always equivalent to the periapsis, and fuel consumption can be reduced by changing the starting point of the powered descent phase. © Institution of Mechanical Engineers.
Heo Y.J.,KARI |
Cho J.,KARI |
CPEM Digest (Conference on Precision Electromagnetic Measurements) | Year: 2010
This paper describes a simple technique to detect discontinuities in GPS clock behavior. We develop a real-time technique to detect GPS clock anomalies. In order to detect sudden jumps in the clock, we employ GPS measurements and the Teager energy operator. The results demonstrate that the proposed clock jump detection scheme can effectively detect clock jumps of less 10 ns from GPS measurements. © 2010 IEEE.
Cho A.,KARI |
Kang Y.-S.,KARI |
Park B.-J.,KARI |
International Conference on Control, Automation and Systems | Year: 2013
The aircraft autopilot needs the feedback of airflow angles, that is, angle-of attack and sideslip angle to control the aircraft. The airflow angles measured by a mechanical vane are not accurate and very noisy for low airspeed. Moreover, the vane has a mechanical failure risk. This paper describes the extended Kalman filter based method to estimate the airflow angles and three-dimensional wind speed under constant wind condition. In addition, it can correct the scaling error of the airspeed of an aircraft. It uses the airspeed measurements, constant wind condition and the sideslip angle computed from GPS/INS navigation data and stability and control derivatives estimated from flight data. Simulation results show that the proposed method works well in various conditions. It is expected that estimated airflow angles will be able to replace the airflow angles measured by a primary system. Estimated wind speed can also be used to reconstruct the GPS/INS navigation system by correcting the airspeed in the case of GPS failure. © 2013 IEEE.
Cho D.-H.,KARI |
International Conference on Control, Automation and Systems | Year: 2014
To design the optimal lunar landing trajectory, the periapsis of de-orbit burn phase is usually used as a starting point of the powered descent phase. And the optimal problem is constructed based on the initial states at this point. For this optimal problem, some kinds of result trajectories have the increase in their own altitude at the early stage to earn the enough time to reduce their huge horizontal velocity for the low thrust, and this phenomenon increase the consumption of the propellant mass. For this reason, it is possible to exist another phase angle to reduce this phenomenon instead of zero for periapsis of de-orbit burn phase because the vertical velocity is not zero at this point. To find out this optimal phase angle, in this paper, the initial free state optimal problem method is applied without any additional assumption and change of hardware for the traditional optimal lunar landing problem. Using this approach, it shows that the optimal phase angle does not always equal to the periapsis for some cases, and it is possible to reduce the fuel consumption of the lunar lander. © 2014 Institute of Control, Robotics and Systems (ICROS).
Cho A.,KARI |
Kang Y.-S.,KARI |
Park B.-J.,KARI |
Yoo C.-S.,KARI |
International Conference on Control, Automation and Systems | Year: 2012
Most aircrafts are equipped with an air data system to measure airspeed, angle-of-sideslip(AOS) and so on. An air data system consists of Pitot-static tube and gimbal-mounted weathervane. The static pressure obtained by Pitot-static tube is affected by fuselage nose and angle-of-attack(AOA). To measure AOA and AOS accurately, weathervane should be placed out of boundary layer around fuselage nose. But due to structural problems, it is not easy to keep sufficient distance between static-hole of Pitot-static tube and fuselage nose. This gives rise to the error of measured air data and it is difficult to correct this error by wind-tunnel test or computational method. Thus, air data system must be calibrated through flight test after installation. This paper proposes the Kalman filter setup to calibrate static pressure, or airspeed and barometric altitude using GPS ground velocity. And also Kalman filter based AOS calibration method is proposed using flight data. Proposed methods are verified by simulation and real flight data of S m a r t U AV. © 2012 ICROS.
News Article | November 22, 2016
Global Aerospace Lubricant Market size was approximately 90 kilo tons in 2015 and is projected to surpass 135 kilo tons in 2024, with estimated gains of more than 4% CAGR. in terms of revenue, the industry is estimated to cross USD 900 million by 2024. Aerospace lubricant improves efficiency of the engine by reducing frictions between two surfaces, resulting in more kilometres in same amount of fuel. Global air traffic grew by 6% owning to increase in the frequency of flights. Rising consumer income resulting in lavish lifestyles along with reduced air fares is anticipated to be the key factor propelling industry growth. Increasing investments in defence by countries including Russia, China and India, will consequently drive industry growth. For instance, China invested over USD 140 billion in 2015 to design and develop aircrafts and missiles with extensive capability. Russia is investing on modernising its armour and fighting vehicles which may fuel aerospace lubricant market size over the forecast timeframe. Request for an in-depth table of contents for this report @ https://www.gminsights.com/request-toc/upcoming/811 Investments on space studies by agencies like NASA, ISRO, Korea aerospace research institute (KARI), Iranian space agency, Japanese Aeronautics exploration agency, European space agency, China national space organisation, may stimulate aerospace lubricant demand owing to widespread product application in spaceships. Spaceship requires high reliability, lifetime lubrication owning to increase demand of lubricants. In spaceships, the products are majorly used in flap actuator, oxygen breathing system, valves & pumps, rocket engine assemblies and bearing in gyroscopes. Gas turbine oil, piston oil, hydraulic fluid and grease are the major products in the global aerospace market share. Gas turbine oil was significant industry share contributor in 2015. It provides efficient cooling and prevents corrosion while the engine is operated owing to increase engine efficiency. It also supports aircraft specifications such as water contamination resistance, high oxidative stability, and reduction of downtime. Piston aerospace lubricants was another substantial industry share contributor in 2015. It reduces over 50% of friction and improvement, which directly impacts on the fuel efficiency. Civil aviation, defence and space are the end users of the aerospace lubricants market share. Civil aviation dominated the end user base and accounted roughly more than 60% of the global volume in 2015. Increasing air traffic China & India, along with lower fares is analysed to be the key factor propelling aerospace lubricants market size for civil aviation. Rising investments on space mission by the U.S., India, Germany and France will favour industry growth. Furthermore, increasing military expenditure in fighter jets by Russia and China will further complement industry growth by 2024. Asia Pacific, mainly led by China, India, Thailand, and Indonesia, and significant aerospace lubricant market size contributor owing to rising air traffic, military and space mission investments in the region. Middle East & Africa (MEA) is witnessing remarkable growth due to urbanisation, and economic development, which has have resulted in increased airbus usage. Growing service industry and tourism in the UAE, Saudi Arabia, Qatar, and Oman are factor fuelling industry growth. Global aerospace lubricant market share is consolidated due to limited number of manufacturers. Major companies operating in the business includes Castrol, Shell, Quaker Chemical Corporation, Fuchs Group, British Petroleum, Petrobras, Chevron Corporation, Exxon Mobil, DuPont, Phillips 66, and Sinopec. Other industry players such as Northrop Grumman and SpaceX provide spaceships and satellites. Industry players are involved in product development with value added characteristics. For instance, DuPont’s Krytox perfluoropolyether (PFPE), is desirable in the industry as it remains unaffected with temperature ranging from -710 F to 7500 F. It also helps in shock & vibration absorption, resistance to vapor loss in vacuum. Global Market Insights, Inc., headquartered in Delaware, U.S., is a global market research and consulting service provider; offering syndicated and custom research reports along with growth consulting services. Our business intelligence and industry research reports offer clients with penetrative insights and actionable market data specially designed and presented to aid strategic decision making. These exhaustive reports are designed via a proprietary research methodology and are available for key industries such as chemicals, advanced materials, technology, renewable energy and biotechnology.