OrbitalHub

Mea AI adiutor dicit:

Sentinel-6B represents the next leap in monitoring our planet’s oceans, a critical mission driven by a collaboration between NASA, NOAA, ESA (the European Space Agency), EUMETSAT, and France’s CNES. Slated for launch in November 2025 aboard a SpaceX Falcon 9 from Vandenberg Space Force Base, this satellite continues a decades-long legacy of radar altimetry measurements that trace back to the TOPEX/Poseidon era.

The heart of Sentinel-6B lies in its mission to precisely measure sea surface height across roughly 90% of the world’s oceans. This is not just a climate mission: the data will feed into operational ocean models, improve weather forecasts, and play a critical role in coastal planning — informing everything from flood risk to shipping routes. Moreover, because sea level is one of the most direct indicators of climate-driven change, Sentinel-6B helps maintain the continuity of a vital long-term dataset.

Beyond ocean heights, Sentinel-6B will also monitor the atmosphere. Using a technique called GNSS radio occultation, it will capture vertical profiles of temperature and humidity in Earth’s atmosphere, enhancing the accuracy of weather prediction models. This atmospheric data even supports NASA’s Engineering Safety Center, helping plan safer reentry paths for future Artemis missions.

The satellite is outfitted with a sophisticated suite of instruments. Its Poseidon-4 altimeter will send radar pulses to the ocean surface and measure their return time to derive sea level measurements. A microwave radiometer (AMR-C) will correct for atmospheric water vapor, which affects radar accuracy. Its GNSS-RO receiver gathers data for the radio occultation measurements, while a DORIS system and a GNSS precise orbit determination package help pin down the satellite’s position with extreme precision. A laser retroreflector array (LRA) further enhances orbit tracking.

The Sentinel-6B mission carries profound implications for climate science, public safety, and operational forecasting. By extending the sea-level record well into the 2030s, it enables scientists and policymakers to track ocean trends with greater fidelity than ever before. This continuity is vital: without it, we risk losing sight of how fast sea levels are changing and which regions are most vulnerable.

As Sentinel-6B prepares for launch, it promises not only to safeguard critical infrastructure but also to deepen our understanding of Earth’s changing climate system. Through robust international collaboration and cutting-edge technology, this mission underscores how satellites remain our most powerful tools in charting the future of our oceans.

Video credit: NASA

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Launched on April 15, 1999, from Vandenberg Air Force Base in California aboard a Delta II rocket, Landsat 7 marked a new chapter in Earth observation. This satellite, a collaborative endeavor between NASA, the U.S. Geological Survey (USGS), and NOAA, was the seventh in the long-running Landsat program that began in 1972. With a sun-synchronous, near-polar orbit at an altitude of approximately 705 kilometers, Landsat 7 was designed to pass over the same part of the Earth every 16 days, capturing high-resolution imagery under consistent lighting conditions at around 10:00 a.m. local solar time.

The spacecraft itself was engineered by Lockheed Martin and featured a three-axis stabilized platform, which allowed precise orientation in space. It drew power from solar arrays supported by nickel-cadmium batteries and used a hydrazine monopropellant system for orbital maintenance. One of its significant upgrades over previous Landsat missions was the inclusion of a solid-state data recorder capable of storing roughly 378 gigabits of data. This feature allowed the satellite to store imagery until it could downlink it to a ground station, enabling more flexible operations and broader global coverage.

At the heart of Landsat 7’s success was its sole scientific instrument: the Enhanced Thematic Mapper Plus (ETM+). This powerful sensor was a “whisk-broom” scanner, capturing data across eight spectral bands. Six of these bands covered the visible, near-infrared, and shortwave infrared portions of the electromagnetic spectrum with a resolution of 30 meters. A thermal infrared band operated at 60 meters resolution, while a high-resolution panchromatic band offered detail at 15 meters. Each scene covered an area of roughly 183 by 170 kilometers.

One of ETM+’s distinguishing features was its rigorous calibration. Equipped with a full-aperture solar calibrator and internal lamps, ETM+ maintained its radiometric accuracy to within five percent. This exceptional calibration made it the gold standard for satellite remote sensing, enabling cross-calibration with other Earth-observing missions such as NASA’s Terra and EO-1 satellites.

However, Landsat 7’s mission was not without challenges. On May 31, 2003, the satellite’s scan line corrector (SLC)—a mechanism that compensated for the motion of the satellite to ensure complete image coverage—failed. This hardware malfunction introduced zigzag-shaped data gaps that affected roughly 22 to 30 percent of each image. Despite the setback, Landsat 7 continued to operate, and the data it captured remained valuable. Scientists developed methods to fill in the gaps using data from adjacent passes, allowing continued scientific use and analysis.

Originally designed for a five-year mission, Landsat 7 exceeded expectations by remaining active for over two decades. In 2017, the final station-keeping maneuvers were performed to maintain the satellite’s orbital parameters. As fuel levels dropped, the satellite’s orbit began to drift slightly, but its imaging capabilities remained intact. In April 2022, the satellite was placed in a lower orbit to support calibration of other Earth-observing systems, and it continued to acquire data intermittently until January 2024. On June 4, 2025, the mission officially came to an end.

Throughout its operational life, Landsat 7 played a vital role in Earth sciences. It provided consistent, high-resolution imagery that supported a wide range of applications, including environmental monitoring, land use planning, disaster response, water resource management, agriculture, and climate change research. The data collected were used in studies that tracked deforestation in the Amazon, urban sprawl in North America, and agricultural patterns in sub-Saharan Africa, among countless other projects.

One of Landsat 7’s most transformative impacts came in 2008, when USGS made its entire Landsat archive—including Landsat 7 data—available to the public at no cost. This decision revolutionized the field of remote sensing, opening the doors to researchers, educators, governments, and businesses worldwide. The number of Landsat scene downloads skyrocketed, leading to an explosion in published scientific studies and practical applications.

Beyond its imagery, Landsat 7 served as a radiometric benchmark. Its ETM+ sensor was so well-calibrated that it became a reference instrument, helping to ensure consistency and accuracy across other satellite missions. This legacy continued with Landsat 8, launched in 2013, and Landsat 9, which entered service in 2021. Even in its final years, Landsat 7 contributed to efforts to standardize Earth observation through proposed servicing missions and calibration support.

Landsat 7’s mission may have ended, but its legacy endures. For over 20 years, it provided humanity with a clearer picture of our changing planet, setting new standards in satellite imaging and democratizing access to Earth observation data. As scientists and decision-makers confront the challenges of climate change, food security, and sustainable development, the insights first captured by Landsat 7 continue to inform policy and shape our understanding of the world.

Video credit: NASA Goddard

Wikipedia dicit:

The Geostationary Operational Environmental Satellite (GOES), operated by the United States’ National Oceanic and Atmospheric Administration (NOAA)’s National Environmental Satellite, Data, and Information Service division, supports weather forecasting, severe storm tracking, and meteorology research. Spacecraft and ground-based elements of the system work together to provide a continuous stream of environmental data. The National Weather Service (NWS) and the Meteorological Service of Canada use the GOES system for their North American weather monitoring and forecasting operations, and scientific researchers use the data to better understand land, atmosphere, ocean, and climate dynamics.

The fourth-generation satellites, the GOES-R series, were built by Lockheed Martin using the A2100 satellite bus. The GOES-R series is a four-satellite program (GOES-R, -S, -T and -U) intended to extend the availability of the operational GOES satellite system through 2036. GOES-R launched on 19 November 2016. It was renamed GOES-16 upon reaching orbit. Second of the series GOES-S, was launched on 1 March 2018. It was renamed GOES-17 upon reaching orbit.

The instrument package for the GOES-R series includes:
Advanced Baseline Imager (ABI)
Space Environment In-Situ Suite (SEISS), which includes two Magnetospheric Particle Sensors (MPS-HI and MPS-LO), an Energetic Heavy Ion Sensor, and a Solar and Galactic Proton Sensor
Solar Imaging Suite, which includes the Solar Ultraviolet Imager (SUVI), the Solar X-Ray Sensor (XRS), and the Extreme Ultraviolet Sensor (EUVS)
Geostationary Lightning Mapper (GLM)
Magnetometer

Video credit: Lockheed Martin

NASA dicit:

This year, the ozone hole over Antarctica reached its annual maximum extent on September 28th, 2024, with an area of 8.5 million square miles (22.4 square million kilometers). The hole, which is actually a region of depleted ozone, was the 20th smallest since scientists began recording the ozone hole in 1979. The average size of the ozone hole between September and October this year was the 7th-smallest since the Montreal Protocol began to take effect.

Video credit: NASA’s Goddard Space Flight Center

Wikipedia dicit:

GOES-U is a weather satellite, the fourth and last of the GOES-R series of satellites operated by the National Oceanic and Atmospheric Administration (NOAA). The GOES-R series will extend the availability of the Geostationary Operational Environmental Satellite (GOES) system until 2036. The satellite is built by Lockheed Martin, based on the A2100 platform.

The satellite is expected to be launched into space atop a SpaceX Falcon Heavy rocket on June 25, 2024, delayed from April 30 2024, from Kennedy Space Center, Florida, United States. The redesign of the loop heat pipe to prevent an anomaly, as seen in GOES-17, is not expected to delay the launch as it did with GOES-T.

GOES-U will also carry a copy of the Naval Research Laboratory’s Compact CORonagraph (CCOR) instrument which, along with the CCOR planned for Space Weather Follow On-Lagrange 1 (SWFO-L1), will allow continued monitoring of solar wind after the retirement of the NASA-ESA SOHO satellite in 2025.

It will have a dry mass of 2,925 kg (6,449 lb) and a fueled mass of 5,000 kg (11,023 lb).

Video credit: Lockheed Martin

Wikipedia dicit:

Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) is a NASA Earth-observing satellite mission that will continue and advance observations of global ocean color, biogeochemistry, and ecology, as well as the carbon cycle, aerosols and clouds. PACE will be used to identify the extent and duration of phytoplankton blooms and improve understanding of air quality. These and other uses of PACE data will benefit the economy and society, especially sectors that rely on water quality, fisheries and food security.

PACE has two fundamental science goals: “to extend key systematic ocean color, aerosol, and cloud data records for Earth system and climate studies, and to address new and emerging science questions using its advanced instruments, surpassing the capabilities of previous and current missions”. The ocean and atmosphere are directly connected, moving and transferring energy, water, nutrients, gases, aerosols, and pollutants. Aerosols, clouds, and phytoplankton can also affect one another.

PACE will measure atmospheric particles and clouds that scatter and absorb sunlight. Improved characterization of aerosol particles will enable quantifying their impact on marine biology and ocean chemistry, as well as Earth’s energy budget and ecological forecasting. PACE will enable scientists to better monitor fisheries, identify harmful algal blooms, and observe changes in marine resources. The color of the ocean is determined by the interaction of sunlight with substances or particles present in seawater such as chlorophyll, a green pigment found in most phytoplankton species. By monitoring global phytoplankton distribution and abundance, the mission will contribute toward understanding the complex systems that drive ocean ecology.

Video credit: SpaceX/NASA’s Kennedy Space Center