As NASA turns 60 on Oct 1, we take a look at why the agency is special and why it is so vital for our planet
NASA is the only federal agency that is capable of studying the impacts of global warming from orbit. It has more than a dozen Earth science spacecraft/instruments in orbit collecting climate data, contributing to reports on everything from the state of the atmosphere to rising sea levels, with several more planned for launch in the next few years.
Other than the humongous amount of data they collect, NASA also has some of the finest scientists who could be called authorities on climate change analyses. It also has collaborations across the world with various government agencies and space agencies for sharing data and analysis.
Landsat
The legendary Landsat program is the longest running earth observation program and provides continuous space-based record of Earth’s land in existence since 1972 when the Earth Resources Technology Satellite was launched. This was eventually renamed to Landsat. The most recent, Landsat 8, was launched on February 11, 2013.
Till date, the Landsat series have acquired millions of images of Earth from space and are a unique resource for global change research and applications in a wide array of fields such as agriculture, cartography, geology, forestry, regional planning, surveillance and education. The program is a NASA collaboration USGS. All Landsat data is publicly available for free and can be viewed through the USGS EarthExplorer website.
Currently, Landsat 7 and 8 are the only on-orbit satellites in series. In April 2015, NASA and USGS announced that work on Landsat 9 had commenced. A land surface mapping satellite,Landsat 9 will collect space-based images and data that serve as resources for researchers in areas that include agriculture, land use mapping, and disaster relief.
Recently, Orbital ATK obtained the approval to begin building manufacturing the spacecraft after completing a comprehensive design review of the mission. Besides design and manufacture, Orbital ATK will also integrate two science instruments on the spacecraft, support the launch, and help in early orbit operations and on-orbit check-out of the observatory. The Landsat 9 spacecraft will be manufactured and tested at Orbital ATK’s Gilbert, Arizona, facility and is currently planned for launch in late 2020.
Terra
Terra is the flagship of NASA‘s Earth Observing System. It carries five instruments that can take coincident measurements of the Earth — Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Clouds and the Earth’s Radiant Energy System (CERES), Multi-angle Imaging SpectroRadiometer (MISR), Moderate Resolution Imaging Spectroradiometer (MODIS) and Measurement of Pollution in the Troposphere (MOPITT).
Launched on December 18, 1999, Terra is the size of a small school bus and moves in a circular sun-synchronous polar orbit that takes it from north to south (on the daylight side of the Earth) every 99 minutes. The instruments onboard Terra concurrently observe the planet including the atmosphere, oceans, land, snow and ice, proving insights into Earth systems such as the water, carbon and energy cycles. The MODIS and ASTER instruments onboard also provide critical information for assessing and managing natural disasters and other emergencies.
LAGEOS
Launched by NASA in 1976, Laser GEOdynamics Satellite-1 (LAGEOS) was the first spacecraft dedicated exclusively to high-precision laser ranging. LAGEOS-2 was built by the Italian Space Agency and came in 1992. Studded with 426 reflectors that return a laser pulse to the source on the ground, give the satellites a jeweled or disco ball kind of a look. Due to the stability of their orbits, LAGEOS provides extremely stable orbital positions against which to measure Earth’s surface. Measuring the laser’s round trip travel times helps scientists to accurately measure distances for studies about Earth’s shape and continent drift.
LAGEOS-1 carries a 4×7 inch stainless steel plaque designed by the famous American scientist Dr Carl Sagan
Plans are afoot for the launch of LAGEOS-3, which is a joint NASA multinational program along with France, Germany, Great Britain, Italy and Spain.
GPM
The Global Precipitation Measurement Mission (GPM) is an international network of satellites that provide the next-generation global observations on rain and snow. It serves as a reference standard to unify precipitation measurements from a constellation of research and operational satellites.
GPM is capable of giving very accurate and timely information on global precipitation and is thus helping to advance our understanding of Earth’s water and energy cycle, improve forecasting of extreme events that cause natural hazards and disasters. The GPM Core Observatory was launched on February 27, 2014.
The GPM Core Observatory design is an extension of the highly successful rain sensing package of the Tropical Rainfall Measuring Mission (TRMM), which focused primarily on heavy to moderate rain over tropical and subtropical oceans. Precipitation data from the GPM and TRMM missions is made available free to the public in a variety of formats from several sources. Through an advanced set of instruments, TRMM and GPM provide new information on precipitation characteristics and how rain and snow interact within the Earth system.
Jason series
The Ocean Surface Topography Mission (OSTM) of the Jason series is an international collaboration of NASA with others to collect ocean surface data that began with the TOPEX/Poseidon satellite mission in 1992, continuing through the Jason-1 (launched in 2001) and the currently operating OSTM/Jason-2 (launched in 2008) missions. NASA and CNES shared the development, construction, and operation of Jason-1 while NOAA and the European Meteorologic Satellite organization (Eumetsat) joined the mission on OSTM/Jason-2. Jason-3, launched on January 17, 2016, has a radar altimeter which measures sea-level variations over the global ocean with very high accuracy (3.3 cm with a goal of achieving 2.5 cm). Long-term measurements will help scientists at NOAA, European weather agencies, marine operators, better understand ocean circulation patterns, global and regional-level changes, and climate change.
GRACE
The twin satellites of the Gravity Recovery and Climate Experiment (GRACE) were launched on March 17, 2002 to make detailed measurements of the changes in Earth’s gravity field for investigations into water reservoirs, earthquakes and crustal deformations. The two GRACE satellites, were retired in 2017 after completing more than 13 years of continuous measurements.
GRACE Follow On mission, a joint project between Nasa and the GFZ German Research Centre for Geosciences in Potsdam, was launched in May 2018, but the satellites had to switch back to its backup system following a glitch. The twin satellites — circling the Earth every 90 minutes at an altitude of 490 km and traveling at a speed of approximately 27,000 kmph — maintain a distance of around 220 km and bounce microwave energy pulses between them, which enable the constant measurement of their relative distance to within a micron, or approximately the length of a red blood cell.
Earlier, data from the GRACE mission helped NASA scientists solve two mysteries about wobbles in Earth’s rotation, which may hold key to knowledge of past and future climate.
SORCE
The Solar Radiation and Climate Experiment (SORCE), launched on January 25, 2003, provides the total amount of sunlight that reaches Earth and how the sun’s output varies over time. It is capable of state-of-the-art measurements of incoming X-ray, ultraviolet, visible, near-infrared, and total solar radiation. SORCE data helps us understand the sun’s impact on Earth’s weather and climate systems, thus enabling scientists to specifically address long-term climate change, natural variability and enhanced climate prediction, and atmospheric ozone and UV-B radiation.
NASA is on course to more accurately monitor the level of solar irradiance that reaches the earth, with the launch of a instrument for the International Space Station. The TSIS-1 spectral irradiance measurements of the sun’s ultraviolet radiation are critical to understanding the ozone layer.
Aqua
Launched on May 4, 2002, Aqua has six Earth-observing instruments on board, and is named for the large amount of information being obtained about water in the Earth system from its stream of approximately 89 Gigabytes of data a day. Its primary mission is to collect data about the Earth’s water cycle, including evaporation from the oceans, water vapor in the atmosphere, clouds, precipitation, soil moisture, sea ice, land ice, and snow cover etc. Today it also collects additional variables including radiative energy fluxes, aerosols, vegetation cover on the land, phytoplankton and dissolved organic matter in the oceans, and air, land, and water temperatures.
Aqua, Latin for water, is part of the international Earth Observing System (EOS). Formerly named EOS PM, signifying its afternoon equatorial crossing time, Aqua was originally developed for a six-year design life but has now far exceeded that original goal.
Because of a 2007 anomaly with the Solid State Recorder (SSR) it can only hold two orbits worth of data. As per current plan, Aqua will leave the “A-Train” constellation in March 2022, with the mission continuing at a lower orbit until 2025. Aqua’s life could be extended with a possible re-fueling mission.
AURA
AURA, Latin for breeze, is for measuring the ozone, gases and aerosols in the Earth’s atmosphere using four innovative instruments. This data is used to study the chemistry of the atmosphere especially changes in the ozone layer, air quality and how they influence climate change.
The Aura spacecraft was successfully launched on July 15, 2004 into a sun-synchronous, near polar orbit. The Aura spacecraft is flying in formation with other Earth observing satellites called the A-Train. Aura flies in formation about 15 minutes behind Aqua in the “A-Train” satellite constellation which consists of several satellites flying in close proximity.
In January this, using measurements from NASA’s Aura satellite, scientists studied chlorine within the Antarctic ozone hole over the last several years and established that the levels of ozone-destroying chlorine are declining, resulting in less ozone depletion.
CALIPSO
CALIPSO, or the short form for Cloud-Aerosol LiDAR and Infrared Pathfinder Satellite Observation, looks into the role of clouds and airborne particles in regulating Earth’s weather, climate, and air quality. CALIPSO is NASA’s JV with the France’s CNES. As the name suggests, CALIPSO has a LiDAR instrument with passive infrared and visible imagers to probe the vertical structure and properties of thin clouds and aerosols over the globe.
CALIPSO was launched on April 28, 2006 with the cloud profiling radar system on the CloudSat satellite. CALIPSO and CloudSat are complementary to each other and the combined data from these two missions provide never-before-seen 3-D perspectives of how clouds and aerosols affect weather and climate. CALIPSO and CloudSat fly in formation with three others in the A-train constellation.
Recently, NASA scientists used observational data from the CALIPSO and Cloudsat satellites to investigate the effects of smoke and pollution on clouds. Looking specifically at deep convective clouds, the study shows that smoky air makes it harder for these clouds to grow. Pollution, on the other hand, energizes their growth, but only if the pollution isn’t heavy. Extreme pollution is likely to shut down cloud growth.
CloudSat
The CloudSat mission, launched on April 28, 2006, is part of NASA‘s Earth System Science Pathfinder program. It has a highly sensitive radar which is 100 times more powerful than a regular weather radar and is capable of penetrating clouds. Its data is combined with CALIPSO for gaining 3D perspectives into on how clouds form and affect weather and climate. CloudSat was developed in collaboration with the Canadian Space Agency in and launched along with CALIPSO in 2006. Its primary mission was to continue for 22 months for allowing more than one seasonal cycle to be observed.
The Earth System Science Pathfinder Program sponsors missions designed to address unique, specific, highly focused scientific issues and to provide measurements required to support Earth science research. Missions selected in this program support a variety of scientific objectives related to Earth science, including studies of the atmosphere, oceans, land surface, polar ice regions, and solid Earth.
OCO-2
Launched on July 2, 2014, Orbiting Carbon Observatory-2 (OCO-2) is NASA’s first dedicated remote sensing satellite to study atmospheric carbon dioxide – considered to be the main culprit behind global warming — from space. It is a replacement of the Orbiting Carbon Observatory which was lost in a launch failure in 2009.
The OCO-2 is capable of making unprecedented, accurate global measurements of CO2 levels in the atmosphere and providing unique information on the natural processes controlling carbon exchange between land and air and between the atmosphere and ocean. OCO-2 data have allowed scientists to study in detail how shifts in rainfall alter the amount of carbon stored or released by vegetation and how changes in ocean temperature affect ocean water’s ability to absorb carbon dioxide. In 2017, scientists used OCO2 data to show how carbon links everything on Earth – the ocean, land, atmosphere, terrestrial ecosystems and human activities.
SMAP
Launched on January 31, 2015, the Soil Moisture Active Passive (SMAP) mission is orbiting observatory that measures the amount of water in the top 5 cm of soil everywhere on Earth’s surface. One of the first Earth observation satellites developed by NASA in response to the National Research Council’s Decadal Survey, SMAP is designed to measure soil moisture over a three-year period every couple of days. This permits changes, around the world, to be observed over time scales ranging from major storms to repeated measurements of changes over the seasons.
Initially, the mission used both active radar and passive (receiving natural microwave emissions from the ground) techniques to measure soil moisture. Even though the radar has stopped working the mission continues, increasing our understanding of links between water, energy and carbon cycles.
The US Department of Agriculture Data recently announced that it is incorporating the SMAP data to monitor global croplands and enable commodity forecasts.
