Kilometers In Altitude Research Articles

Hydro-Magneto-PIC hybrid model for description of debris motion in high altitude nuclear explosions

A Hydro-Magneto-PIC (particle-in-cell) hybrid model is proposed to describe the motion of the fission debris in high altitude nuclear explosions (HANEs). Compared with the state-of-art numerical models, our model is able to stably compute the motion of the fission debris in a broader spatial region. In a real HANE, the physical process contains many spatial scales. The upward moving debris particles manifest kinetic properties due to the fact that the dilute ambient atmosphere and the downward expanding particles manifest a fluid-like pattern and can be approximated by the usual hydro-dynamical models. Meanwhile, the debris particles receive electromagnetic forces from both the geomagnetic fields and the charged particles at all frequencies. This broad scale of frequencies can induce large- and small-scale instabilities, which cannot be solved by the usual hydrodynamic equations. Considering the motions of the debris and the different properties of the high temperature ions, the low temperature ions and the neutral atmosphere, we consistently combine three models for completely describing the debris expansion. The high temperature ions are described by the PIC model for their intrinsic kinetic behaviors, the low temperature ions are described by the magneto-hydrodynamic model for their fluid property, and fluid equations are applied to the neutral particles with no electromagnetic force. The corresponding interactions among the three components are added into the equations as the source terms. With the combination of the three models, our algorithm can stably calculate the regions that are a few thousand kilometers in altitude. Our proposed model contains both the kinetic and fluid properties, and is stable in numerical implementations. Finally, we calculate the debris motion in the Starfish experiment. The results confirm a consistency of our proposed model with the observations. The spatial scale of our simulation results is consistent with the result in the Starfish experiment. In addition, we also plot the distribution of the debris with different projection angles at various snapshots. These results give us an intuition to understand the influence of the various factors, such as the friction of atmosphere, the magnetic pressure, flute instability and the Hall currents. Our model provides a tool for implementing the HANE simulation in a broader scheme, and can also be utilized in other plasma systems.

CubeSats set to tackle living systems, effects of deep space radiation

Human beings will soon be heading into deep space again, decades after the Apollo missions. Out there, beyond Earth’s magnetic shield, they will be exposed to intense radiation for months or years, a cosmic onslaught that could cause all sorts of damage. But a fleet of tiny bio-laboratories may offer up insights that will help protect future astronauts. BioSentinel, seen here in a conceptual drawing, is the first CubeSat aiming to investigate the pernicious effects of deep-space radiation. Image courtesy of NASA. These intrepid explorers are CubeSats, built up from 10 × 10 × 10-centimeter units, in a somewhat standardized format originally laid out in 1999. CubeSats are cheap and quick to build, making them popular with telecommunications companies and scientists alike. In May, for example, a small fleet of CubeSats, called QB50, set off from the International Space Station to explore a little known layer of the Earth’s outer atmosphere between 100 and 300 kilometers in altitude. And now these tiny satellites are being adapted to pave the way for human missions to the moon, Mars, and beyond. These marvels of miniaturization will squeeze in samples, nutrients, plumbing, and even microscopes, to send back images and other data on suffering cells millions of miles away—all to help us understand and maybe reduce the pernicious effects of space radiation. The first of these CubeSats should go up a year or two from now. BioSentinel is a six-liter spacecraft built at NASA’s Ames research center in Moffett Field, California (1). “We at Ames have been the only ones clever or foolish enough to do live biology experiments on CubeSats,” says payload technologist Tony Ricco. So far the team has flown four biological CubeSat missions. One, O/OREOS, looked at radiation damage in a spore-forming bacterium, comparing their growth with identical samples held …

AUTOMATED FORMOSAT IMAGE PROCESSING SYSTEM FOR RAPID RESPONSE TO INTERNATIONAL DISASTERS

FORMOSAT-2, Taiwan’s first remote sensing satellite, was successfully launched in May of 2004 into the Sun-synchronous orbit at 891 kilometers of altitude. With the daily revisit feature, the 2-m panchromatic, 8-m multi-spectral resolution images captured have been used for researches and operations in various societal benefit areas. This paper details the orchestration of various tasks conducted in different institutions in Taiwan in the efforts responding to international disasters. The institutes involved including its space agency-National Space Organization (NSPO), Center for Satellite Remote Sensing Research of National Central University, GIS Center of Feng-Chia University, and the National Center for High-performance Computing. Since each institution has its own mandate, the coordinated tasks ranged from receiving emergency observation requests, scheduling and tasking of satellite operation, downlink to ground stations, images processing including data injection, ortho-rectification, to delivery of image products. With the lessons learned from working with international partners, the FORMOSAT Image Processing System has been extensively automated and streamlined with a goal to shorten the time between request and delivery in an efficient manner. The integrated team has developed an Application Interface to its system platform that provides functions of search in archive catalogue, request of data services, mission planning, inquiry of services status, and image download. This automated system enables timely image acquisition and substantially increases the value of data product. Example outcome of these efforts in recent response to support Sentinel Asia in Nepal Earthquake is demonstrated herein.

AUTOMATED FORMOSAT IMAGE PROCESSING SYSTEM FOR RAPID RESPONSE TO INTERNATIONAL DISASTERS

Abstract. FORMOSAT-2, Taiwan’s first remote sensing satellite, was successfully launched in May of 2004 into the Sun-synchronous orbit at 891 kilometers of altitude. With the daily revisit feature, the 2-m panchromatic, 8-m multi-spectral resolution images captured have been used for researches and operations in various societal benefit areas. This paper details the orchestration of various tasks conducted in different institutions in Taiwan in the efforts responding to international disasters. The institutes involved including its space agency-National Space Organization (NSPO), Center for Satellite Remote Sensing Research of National Central University, GIS Center of Feng-Chia University, and the National Center for High-performance Computing. Since each institution has its own mandate, the coordinated tasks ranged from receiving emergency observation requests, scheduling and tasking of satellite operation, downlink to ground stations, images processing including data injection, ortho-rectification, to delivery of image products. With the lessons learned from working with international partners, the FORMOSAT Image Processing System has been extensively automated and streamlined with a goal to shorten the time between request and delivery in an efficient manner. The integrated team has developed an Application Interface to its system platform that provides functions of search in archive catalogue, request of data services, mission planning, inquiry of services status, and image download. This automated system enables timely image acquisition and substantially increases the value of data product. Example outcome of these efforts in recent response to support Sentinel Asia in Nepal Earthquake is demonstrated herein.

Model of Earth's plasmasphere is incompatible with measurements

A widely used model of Earth's plasmasphere does not match observations, a new study indicates. Electron density in the plasmasphere—the region of cold, dense plasma that lies above about 1000 kilometers in altitude—plays a key role in space weather and affects how electromagnetic signals propagate.

Geomagnetic storms affect ozone in mesosphere

During geomagnetic storms, energetic electrons enter the upper mesosphere around 70 kilometers above the Earth's surface. These energetic electrons enhance the chemical reactions that produce nitrogen oxides (NOx), which can destroy ozone. If the nitrogen oxides are transported downward to lower altitudes in the stratosphere (below about 40 kilometers in altitude), they can destroy ozone in the ozone layer that protects life on Earth's surface from harmful ultraviolet radiation. Large solar energetic particle events have been shown to cause decreases in stratospheric ozone, but those large events are uncommon. The extent to which more common moderate‐sized geomagnetic storms affect middle atmosphere chemistry has been uncertain.

The Possibility of Space Tourism in India: Issues and Concerns

Dennis Tito opened the eyes of world to the idea of orbital space tourism when he became the first private space traveler in 2001. Three years later, the Burt Rutan and Paul Allen led team of Mojave Aerospace Ventures won Ansari X-Prize by successfully completing two piloted sub-orbital flights of a reusable vehicle to 100 kilometers in altitude within a span of two weeks. This accomplishment demonstrated to the public and government managers the potential for entrepreneurial commercial activities to change the landscape of the space industry. And now we can see renowned organization like Virgin Galactic, Space X, Armadillo Aerospace, Blue Origin, Bigelow Aerospace and Xcor Aerospace has already not only joined the race of space tourism project but they are also making a remarkable progress. However we see Indian venture has not yet joined for space tourism project. Meanwhile it is believed that India can play a vital role in developing a very cost effective solution for space travel technologies, thus it imperative to investigate the possibility of space tourism in India. In this paper the potential and possibility of space tourism industry in India has been explored. It examines the potential market and cost structure for both suborbital and orbital space travel. Apart from this major issues with the development of the fledgling space tourism industry in India has been identified which need to be addressed in order to promote the growth of this industry. Keywords LEO: Low Earth Orbit, ISS: International Space Station, IRR: Internal Rate of Return, NPV: Net Present Value

Comparison with observations shows cloud simulations improving

Climate projections, such as those used by the Intergovernmental Panel on Climate Change, rely on models that simulate physical properties that affect climate, including clouds and water vapor content. Clouds and water vapor are difficult to simulate in global climate models because they are affected by small‐scale physical processes, and cloud feedback on climate is therefore a large source of uncertainty in climate predictions. A new study finds that model simulations of vertically averaged cloud water amount have improved in recent years. Jiang et al. developed a quantitative scoring method to evaluate the accuracy of 19 climate models at various vertical heights between the surface and the tropopause (16–18 kilometers in altitude) over the tropical oceans (30°N–30°S). They compared the models' simulated multiyear mean of cloud water content and water vapor with observations made using several NASA satellites.

Recent advances in turbulence prediction

Turbulence in the upper troposphere and the lower stratosphere (8–14 kilometers in altitude) is a well‐known aviation hazard; it is the major cause of injuries and occasional fatalities to passengers and crew members on commercial aircraft. Jet streams, thunderstorms, flow over mountains, and even the passage of other aircraft cause turbulence. However, the lack of precise observational data (which is still mainly from pilots reporting turbulence) and a clear understanding of the processes that cause turbulence make it difficult to accurately forecast aviation‐scale turbulence. Hence, upper troposphere and lower stratosphere turbulence forecasting is an area of active research.

Understanding ionospheric instabilities eludes current approaches

Ionized gases are heavily concentrated in the ionosphere's F zone, the region between 200 and 500 kilometers in altitude, which is critical for transmitting long‐distance radio signals on Earth. However, instabilities in the F region plasma, which can last from seconds to hours and can be spread over centimeters to tens of kilometers, disrupt transmission of radio signals. The plasma instabilities, restricted to the equatorial region following sunset, are called equatorial spread F (ESF). Earth‐based instruments perceive ESF events as “twinkling” radio signals. ESF events, first detected in the 1930s, affect the performance and reliability of space‐borne and ground‐based electronic systems; they can disrupt satellite operations and related communications and navigation systems.

Satellite tracks seasonal changes in atmospheric heavy water

From 10 to 30 kilometers in altitude, the steadily decreasing temperatures in the upper troposphere and lower stratopshere cause water vapor containing the hydrogen isotope deuterium—HDO, or heavy water—to preferentially condense out of the air, falling back toward the surface as ice. This selective depletion of heavy water leads, in theory, to a 90% drop in the ratio of heavy water to regular water vapor concentrations as compared to surface levels. The observational record, however, does not always align so well with theoretical predictions. Researchers suspect that skewed heavy water concentrations are due to atmospheric mixing, where deuterium‐ laden water from lower altitudes is transported upward. By tracking changes in the HDO/H2O ratio, researchers hope to tease out the history of evaporation, condensation, and convection that affect a particular atmospheric region.

South Korea's renewed focus on space weather

South Korea's renewed focus on space weather

Iceland's Grímsvötn volcano erupts

About 13 months after Iceland's Eyjafjallajökull volcano began erupting on 14 April 2010, which led to extensive air traffic closures over Europe, Grímsvötn volcano in southeastern took its turn. Iceland's most active volcano, which last erupted in 2004 and lies largely beneath the Vatnajökull ice cap, began its eruption activity on 21 May, with the ash plume initially reaching about 20 kilometers in altitude, according to the Icelandic Meteorological Office. Volcanic ash from Grímsvötn has cancelled hundreds of airplane flights and prompted U.S. president Barack Obama to cut short his visit to Ireland. As Eos went to press, activity at the volcano was beginning to subside.

Water vapor trends over Boulder, Colorado

Water vapor in the atmosphere is responsible for a significant portion of the greenhouse effect, and even small changes in the upper troposphere or lower stratosphere can have a large effect on climate. A new analysis of water vapor measurements by balloon‐borne frost point hygrometers over Boulder, Colo., shows that stratospheric water vapor has increased over the past 30 years. Hurst et al. broke the long measurement record into four discrete time periods and determined the water vapor trends in each period for five 2‐kilometer‐thick stratospheric layers (16–26 kilometers in altitude). The scientists found that, on average, stratospheric water vapor increased by about 1 part per million by volume (27%) over the past 30 years, though there were many shorter‐term variations in the record. Water vapor levels increased during 1980–1989 and 1990–2000, decreased from 2001 to 2005, and then increased again after 2005. The authors found that, at most, 30% of the observed water vapor increases can be attributed to greater amounts of methane oxidation in the stratosphere. The 2001–2005 decrease in midlatitude water vapor has been linked to observations of anomalously low tropopause temperatures in the tropics, but, to date, no connection between the observed water vapor increases and tropical tropopause temperatures has been found despite ongoing efforts. (Journal of Geophysical Research‐Atmospheres, doi:10.1029/2010JD015065, 2011)

Atmospheric Remote Sensing on the International Space Station

The Remote Atmospheric and Ionospheric Detection System (RAIDS) is a new NASA experiment studying the Earth's thermosphere and ionosphere from a vantage point on the International Space Station (ISS). The RAIDS mission focuses on the coupling and transition from the coldest part of the atmosphere, the mesopause near 85 kilometers, up to the hottest regions of the thermosphere, above 300 kilometers in altitude. Built jointly by the Naval Research Laboratory (NRL) and The Aerospace Corporation, RAIDS also is serving as a pathfinder experiment for atmospheric remote sensing aboard the ISS. RAIDS and a companion experiment, NRL's Hyperspectral Imager for the Coastal Ocean (HICO), make up the HICO‐RAIDS Experiment Payload (HREP), the first U.S. payload on the Japanese Experiment Module—Exposed Facility (JEM‐EF). The experience developing and operating RAIDS for this mission provides useful insights for utilizing the ISS as a platform for atmospheric science.

Research Spotlight: Large atmospheric study investigates tropical tropopause transition layer

The tropical tropopause transition layer (TTL), starting at about 12 kilometers in altitude, is a transition layer between the tropical troposphere (the layer nearest Earth) and the stratosphere above. The TTL can influence the chemistry of the stratosphere, including the global ozone budget. In addition, understanding how water and other greenhouse gases behave in the TTL is important to understanding the greenhouse effect and global climate change.

Research Spotlight: Why is the density of the thermosphere abnormally low?

The total mass density of the upper thermosphere (∼200–600 kilometers in altitude) was lower during the 2008 solar minimum than at any other time during the space age. Using historical records of thermospheric density, Emmert et al. compared the behavior of the thermosphere during the recent solar minimum with its

Research Spotlight: Conditions in the stratosphere influence the ionosphere

Variations in the ionosphere, the charged upper portion of Earth's atmosphere (about 100–1000 kilometers in altitude), can affect radio communications and navigation systems. Solar activity is known to strongly influence the ionosphere; recently, though, scientists have recognized that lower levels of the atmosphere can also affect ionospheric conditions. These effects have been hard to see because the ionosphere varies so rapidly in response to solar and geomagnetic activity.

Research Spotlight: Ozone recovery and climate change will affect the atmosphere near Earth's surface

Ozone in the stratosphere (∼10–50 kilometers in altitude) helps protect life on Earth from harmful solar ultraviolet radiation. But at the lower altitudes in the troposphere, (0–10 kilometers in altitude), ozone is a major constituent of smog and has detrimental health effects. The stratospheric ozone layer had been depleted but recently has started to recover due to efforts to limit emissions of ozone‐ depleting chemicals.

Mount St. Helens: A 30‐Year Legacy of Volcanism

The spectacular eruption of Mount St. Helens on 18 May 1980 electrified scientists and the public. Photodocumentation of the colossal landslide, directed blast, and ensuing eruption column—which reached as high as 25 kilometers in altitude and lasted for nearly 9 hours—made news worldwide. Reconnaissance of the devastation spurred efforts to understand the power and awe of those moments (Figure 1).The eruption remains a seminal historical event—studying it and its aftermath revolutionized the way scientists approach the field of volcanology. Not only was the eruption spectacular, but also it occurred in daytime, at an accessible volcano, in a country with the resources to transform disaster into scientific opportunity, amid a transformation in digital technology. Lives lost and the impact of the eruption on people and infrastructure downstream and downwind made it imperative for scientists to investigate events and work with communities to lessen losses from future eruptions.