National Aeronautics and Space Administration NASA

THE NATIONAL AERONAUTICS and Space Administration (NASA) is an independent U.S. governmental agency, established in 1958, for the research and development of vehicles and activities for the exploration of space within and outside of Earth's atmosphere. Within NASA, the Goddard Institute for Space Studies (GISS) at Columbia University in New York carries out research related to climate change and global warming. NASA is structured around five program offices. Aeronautics and Space Technology is responsible for the development of equipment. Space Science and Applications deals with programs for understanding the origin, structure, and evolution of the universe, the solar system, and the Earth. Space Flight is concerned with manned and unmanned space transportation and all matters related to the space shuttle. Space Tracking and Data involves tracking and data acquisition. Space Station has the long-term goal of establishing a manned space station. A number of additional research centers are affiliated, including the Goddard Space Flight Center in Greenbelt, Maryland, within which the Goddard Institute for Space Studies operates; the Jet Propulsion Laboratory in Pasadena, California; the Lyndon B. Johnson Space Center in Houston, Texas; and the Langley Research Center in Hampton, Virginia. NASA headquarters are in Washington, D.C.

NASA was created largely in response to the Soviet launching of Sputnik in 1957. It was organized around the National Advisory Committee for Aeronautics (NACA), which had been created by Congress in 1915. NASA's organization was already underway by the early years of President John F. Kennedy's administration, when the President proposed that the United States sent a man to the Moon by the end of the 1960s. To that end, the Apollo program was designed, and, in 1969, the U.S. astronaut Neil Armstrong became the first man on the Moon. Later unmanned programs, such as Viking, Mariner, Voyager, and Galileo, explored other bodies of the solar system. When NASA began its operation on October 1, 1958, the agency consisted of only about 8,000 employees and had an annual budget of $100 million. In addition to a small headquarters staff in Washington, D.C., that conducted operations, NASA had three major research laboratories inherited from the National Advisory Committee for Aeronautics: the Langley Aeronautical Laboratory established in 1918, the Ames Aeronautical Laboratory activated near San Francisco in 1940, and the Lewis Flight Propulsion Laboratory built at Cleveland, Ohio, in 1941. It also had two small test facilities, one for high-speed flight research at Muroc Dry Lake in the high desert of California, and one for sounding rockets at Wallops Island, Virginia. It soon added several other government research organizations.

The Apollo program was designed to land humans on the Moon and bring them safely back to Earth. Apollo 8 and Apollo 10 tested various components while orbiting the Moon, and returned photographs of the lunar surface. On July 20, 1969, Apollo 11 landed the first man on the moon, Neil Armstrong.

The Apollo program included six missions that landed on the Moon and returned a wealth of scientific data and almost 882 lbs. (400 kg) of lunar samples. Experiments addressed topics such as soil mechanics, mete-oroids, seismic, heat flow, lunar ranging, magnetic fields, and solar wind experiments. NASA was also in charge of the development and launch of a number of satellites with Earth applications, such as Landsat, a series of satellites designed to collect information on natural resources and other Earth features; communications satellites; and weather satellites. It also planned and developed the space shuttle, a reusable vehicle capable of carrying out missions that cannot be conducted with conventional spacecraft. The spectacular successes of the agency is tempered by the controversies and tragic disasters that marked its space shuttle program. The flights of the shuttle turned out to be much more expensive than initially expected. On January 28, 1986, the Space Shuttle Challenger was destroyed during its launch from the Kennedy Space Center. The explosion occurred 73 seconds into the flight as a result of a leak in one of two Solid Rocket Boosters that ignited the main liquid fuel tank. On February 1, 2003, the Space Shuttle Columbia broke up about 15 minutes before the scheduled landing. In both cases, all the astronauts on board lost their lives. The Space Shuttle Columbia disaster, in 2003, caused a 29-month interruption in space shuttle flights and led to a serious re-examination of NASA's priorities. The U.S. government, various scientists, and the public all reconsidered the future of the space program.

The shuttle, however, was also used to launch milestone projects like the Hubble Space Telescope (HST) in 1990, which has proved popular with both scientists and the public. Some of the images it has returned have attained an almost legendary status, such as the groundbreaking Hubble Deep Field images. The shuttle was also instrumental in the creation of the International Space Station (ISS), a cooperative project that mainly involves the United States and Russia for the construction of the biggest space station ever built. Costing over $100 billion, it has been difficult at times for NASA to justify the ISS. During much of the 1990s, NASA also faced shrinking annual budgets because of Congressional belt-tightening. This caused NASA administrators to adopt the "faster, better, cheaper" approach that enabled the agency to cut costs, while still delivering a wide variety of aerospace programs. Yet, that method was criticized and re-evaluated following the twin losses of the Mars Climate Orbiter and the Mars Polar Lander in 1999.

NASA's ongoing investigations include in-depth surveys of Mars and Saturn and studies of the Earth and Sun. Other NASA spacecraft are presently en route to Mercury and Pluto. With its spacecraft and satellites, the agency covers over half the solar system. In 2004, President George W. Bush launched the Vision for Space Exploration, which contemplates another human landing on the Moon by 2020, and the establishment of outposts in preparation for human exploration of Mars and other destinations.

From 2002 to 2006, the mission statement of the agency included understanding and protecting "our home planet." Since February 2006, however, the statement has been reworded and the portion pertaining to understanding and protecting our home planet has been deleted. This has been read by some as a result of the controversy concerning some NASA scientists such as James Hansen and the U.S. governments over the issue of global warming. Hansen, the director of the GISS, bitterly criticized the Bush Administration for what he thought were its ineffective environmental policies. In 2005 and 2006, Hansen also claimed that NASA officials were closely monitoring his participation in public events where he was invited to speak about global warming. This was part of an attempt to influence his statements on global warming. NASA officials have denied that the mission statement has been altered because of the controversy on global warming, but simply reflects the priority of space exploration for the agency in the coming years. They have also denied trying to manipulate Hansen and monitoring his scientific activities. Yet, Hansen has restated his accusations in the Al Gore-hosted documentary An Inconvenient Truth (2006).

The NASA sector that deals with research on climate change and global warming is the GISS, located at Columbia University's Armstrong Hall, in New York City. GISS is a component laboratory of Goddard Space Flight Center's Earth Sciences Division, which is part of GSFC's Sciences and Exploration Directorate. The institute was originally established, in May 1961, by Dr. Robert Jastrow to do basic research in space sciences in support of Goddard programs. The initial research at the Institute focused on planetary atmospheres using data collected by telescopes and space probes; in time that led to GISS becoming a leading center of atmospheric modeling and of climate change. The Institute currently encompasses a broad study of Global Change, treating it as an interdisciplinary initiative addressing natural and anthropogenic changes in our environment. These can occur on various timescales (from one-time forcings, such as volcanic explosions, to seasonal/annual effects, such as El Niño, and on up to the millennia of ice ages) and have a different impact on the habit-ability of the planet. Program areas at GISS may be roughly divided into the categories of climate forcings, climate impacts, model development, Earth observations, planetary atmospheres, paleoclimate, radiation, atmospheric chemistry, astrophysics and other disciplines. However, due to the interconnections among these topics and the interdisciplinary approach, most GISS personnel are engaged in research in several of these areas.

The main aim of GISS researchers is the prediction of atmospheric and climate changes in the 21st century. Their research combines analysis of comprehensive global datasets, derived mainly from spacecraft observations, with global models of atmospheric, land surface, and oceanic processes. GISS studies past climate change on Earth, and of other planetary atmospheres, as a useful tool in assessing our general understanding of the atmosphere and its evolution. The perspective provided by space observations is crucial for monitoring global change and for providing data needed to develop an understanding of the Earth system. As the principal NASA center for Earth observations, Goddard Space Flight Center plays a leading role in global change research. Global change studies at GISS are coordinated with research of other groups within the Earth Sciences Division, including the Laboratory for Atmospheres, Laboratory for Hydrospheric and Biospheric Sciences, and Earth Observing System science office.

The Climate Modeling Program at GISS attempts to develop three-dimensional general circulation models (GCMs) and coupled atmosphere-ocean models for simulating the Earth's climate system. Some research efforts may also include the use and development of two-dimensional energy balance models (EBMs), and one-dimensional radiative-convective models (RCMs). Primary emphasis in the use of the GCMs is placed on investigation of climate sensitivity, including the climate system's response to such forcings as solar variability, and anthropogenic and natural emissions of greenhouse gases and aerosols. GISS GCM simulations study the potential for humans to impact the climate, as well as the impact of a changing climate on society and the environment. GCM research focuses on sensitivity to parameterizations of clouds and moist convection, ground hydrology, and ocean-atmosphere-ice interactions, as well as explorations of more accurate numerical methods. The program also involves the advance of techniques to understand global cloud properties from satellite radiance measurements of the International Satellite Cloud Climatology Project. Ongoing field and laboratory programs in palynology, paleoclimate reconstruction, and other geophysical sciences offer fundamental climate data for evaluating and validating model predictions.

Research in the area of Earth Observation builds on the assumption that satellites provide the potential for observing changes of the Earth system on a global scale. GISS attempts to define which satellite observations are needed for the advancement of research, and to study how satellite data relates to and supports data acquired using more conventional techniques. Satellite observations are analyzed to obtain information on the Earth's surface, atmosphere, and, especially, global cloud systems. GISS is particularly interested in clouds, because they represent a great source of uncertainty in predicting future climate. Clouds are potentially the most powerful feedback mechanism in the climate system. Thus, further research is needed to decide if they are a positive feedback, which will enhance future greenhouse warming, or a negative feedback.

As far as climate impacts are concerned, GISS aims to develop a complex framework of analysis for interactions among biophysical and socioeconomic processes. GISS research in this area investigates the sequence of causes and effects linking climate and its impacts, utilizing the GISS global climate model (GCM), physically based impact models, chemical tracer models, and interdisciplinary teams. Distinctive features of research methods in this field include regional disaggregation, high spatial and temporal resolution, and theoretical improvement in the treatment of uncertainty. GISS climate impacts study addresses the impacts of current climate variability, such as El Niño Southern Oscillation (ENSO) events, and potential impacts of climate change resulting from greenhouse gas emissions. Observed climate data and climate model outputs (temperature, precipitation, solar radiation) are used as inputs for impact models to produce regional changes in variables such as crop yields, water availability, and forests. These changes are then measured in terms of economic and social costs, including the number of people threatened by hunger, drought, or coastal storm surges.

Studies in Planetary Atmosphere, a long-standing tenet of NASA, enables testing of basic understanding of atmospheric processes, including the greenhouse effect, aerosol and cloud physics, and atmospheric chemistry and dynamics. Aware of the difficulty interpreting observational data without comparing them to the results of an atmospheric model, GISS researchers use a variety of models, from relatively simple simulations of radiative transfer to full-fledged general circulation models (GCMs). The more complex models, developed through the conversion of Earth GCMs, allow the study of dynamical atmospheric processes, including the role of eddy, diabatic, and dissipative processes in the context of comparative planetary meteorology.

GISS Paleoclimate research is based upon the use of global climate models (GCMs) to generate simulations of past climates. GCMs are employed, in combination with geophysical, geochemical and sedimentological data analyses, to reconstruct various time periods and events in the Earth's climate history. Paleoclimate simulations are also used to test the ability of GISS digital representations of climates that differ significantly from the present. The ability to simulate climate changes that occurred in the past strengthens confidence in the conclusions drawn from simulations of future climate.

Several warm time periods are also of particular interest, because they provide insights regarding processes and impacts related to global warming scenarios.

Radiation studies at GISS cover three main areas: the construction of accurate radiative transfer models, which allow the interpretation of remote sensing data of Earth and other planets obtained from ground-based and satellite sensors; the accurate and efficient calculations of radiative transfer to determine heating and cooling rates in computer models of climate; and the theoretical modeling required to improve the methods and approximations used in radiative models. Theoretical modeling can also provide fundamental understanding of the physical processes involved in the absorption, scattering, and emission of electromagnetic energy. The study of radiation at GISS follows an interdisciplinary pattern, interacting with other fields, such as atmospheric chemistry, climate modeling, Earth observations, and planetary atmospheres. Projects in radiation studies include understanding the water vapor continuum absorption, modeling the effect of aerosols, as well as trying to retrieve their microphysical properties, analysis of aircraft and ground-based data, and understanding the difference between broadband and narrowband flux retrievals.

Research in atmospheric chemistry at GISS includes both near-term issues, such as air quality and ozone depletion, and the longer-term linkages between atmospheric chemistry and global climate.

GISS works cooperatively with area universities and research organizations, most especially with Columbia University. Almost half of GISS personnel are members of Columbia's Center for Climate Systems Research (CCSR) and also work with researchers at Columbia's Earth Institute and Lamont-Doherty Earth Observatory. Systems and programming support for GISS is provided by Sigma Space Partners, a joint venture of Sigma Space Corp. and SGT, Inc.

SEE ALSo: Bush (George W.) Administration; Climate.

BIBLioGRApHY. Neil Armstrong, et al., America in Space: Nasa's First Fifty Years (Harry Abrams, 2007); National Aeronautics and Space Administration, www.nasa.gov (cited November 2007).

LuCA PRONO University of Nottingham

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