OrbitalHub

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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

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Honeybee Robotics, a subsidiary of Blue Origin, contributed two innovative instruments—LISTER and LPV—to Firefly Aerospace’s Blue Ghost Mission 1, which successfully landed on the Moon in March 2025 as part of NASA’s Commercial Lunar Payload Services (CLPS) program. These instruments are pivotal in advancing our understanding of the Moon’s thermal properties and developing efficient regolith sampling techniques for future lunar exploration.

LISTER: Lunar Instrumentation for Subsurface Thermal Exploration with Rapidity

LISTER is designed to measure the heat flow from the Moon’s interior, providing insights into the Moon’s thermal evolution and internal structure. By assessing how heat escapes from the lunar interior, scientists can infer details about the Moon’s composition and geological history.

LISTER is a collaborative effort between Honeybee Robotics and Texas Tech University. It employs a sophisticated pneumatic drill capable of penetrating up to 3 meters into the lunar regolith. At every 0.5-meter interval, the drill pauses to deploy a custom-built thermal probe that measures temperature gradients and thermal conductivity at various depths. LISTER weighs approximately 4.3 kilograms.

During its operation on the lunar surface, LISTER successfully drilled into the regolith and collected thermal data at multiple depths. These measurements are crucial for understanding the Moon’s internal heat flow and contribute to models of its thermal and geological evolution. The data also aid in assessing the Moon’s suitability for future human habitation and resource utilization.

LPV: Lunar PlanetVac

LPV is a technology demonstration aimed at efficiently collecting lunar regolith samples. Its success is vital for future missions that require in-situ resource utilization or sample return capabilities.

LPV is installed on one of the Blue Ghost lander’s legs. It utilizes a burst of compressed gas to dislodge and propel regolith particles into a collection chamber. Capable of collecting particles up to 1 centimeter in diameter. Features a tube that transports the collected material to onboard instruments for analysis or storage.

LPV successfully demonstrated its ability to collect and transfer lunar soil samples using its gas-driven mechanism. The efficient and contamination-free sampling process validates LPV’s potential for future missions that aim to analyze or return lunar materials to Earth. Its performance also provides valuable data for refining regolith collection techniques in low-gravity environments.

Blue Ghost Mission 1, which landed in Mare Crisium, carried a total of ten NASA payloads, including LISTER and LPV. The mission operated for a full lunar day (~14 Earth days), during which all instruments performed their designated tasks. The successful deployment and operation of LISTER and LPV not only achieved their scientific objectives but also demonstrated the viability of these technologies for future lunar exploration endeavors. Their contributions are instrumental in paving the way for sustained human presence on the Moon and the development of lunar resources.

Video credit: Blue Origin

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The Neutron Star Interior Composition Explorer (NICER) is a NASA mission launched in June 2017 and mounted on the International Space Station (ISS). Its primary objective is to study neutron stars—ultra-dense remnants of massive stars that have undergone supernova explosions. By observing X-ray emissions from these celestial objects, NICER aims to provide insights into their internal structures and the fundamental physics governing matter under extreme conditions.

NICER’s core component is the X-ray Timing Instrument (XTI), designed for high-precision timing and spectroscopy of soft X-rays in the 0.2–12 keV energy range. The XTI comprises 56 co-aligned X-ray concentrator optics, each paired with a silicon drift detector. These concentrators utilize grazing-incidence optics with 24 nested mirrors to focus incoming X-rays onto their respective detectors, enhancing sensitivity and resolution.

NICER is mounted on the ISS’s ExPRESS Logistics Carrier-2. It features a two-axis pointing system that allows the instrument to track celestial targets across the sky. An integrated star tracker ensures precise alignment, enabling NICER to observe multiple targets during each 92-minute orbit of the ISS.

To achieve its scientific goals, NICER incorporates a GPS-based timing system capable of tagging photon arrival times with sub-microsecond accuracy. This high temporal resolution is crucial for studying the rapid rotational periods of pulsars and other time-sensitive phenomena.

NICER has significantly advanced our understanding of neutron star interiors by providing precise measurements of their masses and radii. These observations have helped constrain the equation of state for ultra-dense matter, shedding light on the behavior of matter at densities exceeding those found in atomic nuclei.

An extension of NICER’s mission, known as SEXTANT (Station Explorer for X-ray Timing and Navigation Technology), successfully demonstrated the use of X-ray pulsars for autonomous spacecraft navigation. By measuring the timing of X-ray pulses from known pulsars, SEXTANT was able to determine the ISS’s position in space, paving the way for future deep-space navigation systems.

In 2018, NICER discovered an X-ray pulsar in the fastest known stellar orbit, with a companion star completing an orbit every 38 minutes. This finding provides valuable data on the dynamics of compact binary systems and the extreme gravitational environments in which they exist.

NICER observed the brightest X-ray burst ever recorded from the neutron star SAX J1808.4−3658. This event offered insights into thermonuclear processes on neutron star surfaces and the mechanisms driving such energetic emissions.

Although primarily focused on neutron stars, NICER has also contributed to black hole research. It mapped “light echoes” from the stellar-mass black hole MAXI J1820+070, revealing changes in the size and shape of the surrounding accretion disk and corona. These observations enhance our understanding of black hole accretion processes and their immediate environments.

In May 2023, NICER’s thermal shields developed a leak, allowing stray light to interfere with its X-ray detectors. To address this issue, NASA designed specialized patches delivered to the ISS via the Cygnus NG-21 resupply mission in August 2024. Astronauts successfully applied these patches during a spacewalk on January 16, 2025, restoring NICER’s full observational capabilities.

As of early 2025, NICER has contributed to over 300 scientific publications, underscoring its significant role in advancing astrophysical research. Its high-precision measurements continue to provide valuable data for the scientific community, enhancing our understanding of neutron stars and other cosmic phenomena.

Video credit: NASA Goddard

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SpaceX’s Fram2 mission, launched on March 31, 2025, from Kennedy Space Center, marked a historic milestone as the first human spaceflight to orbit over Earth’s polar regions. This privately funded mission, led by cryptocurrency entrepreneur Chun Wang, featured a diverse international crew and aimed to advance scientific research and exploration.

The mission’s name, Fram2, pays homage to the Norwegian exploration ship Fram, symbolizing a new era of polar exploration—this time from space. The spacecraft completed multiple orbits over both the North and South Poles, providing unprecedented views and data.

The crew members are:

Chun Wang (Mission Commander): A Maltese entrepreneur of Chinese origin and founder of F2Pool, Wang financed the mission.

Jannicke Mikkelsen (Capsule Commander): A Norwegian cinematographer specializing in extreme environments.

Rabea Rogge (Pilot): A German robotics researcher and the first German woman in space.

Eric Philips (Mission Specialist & Medical Officer): An Australian polar explorer and guide.

All crew members were civilians with backgrounds in exploration and science, emphasizing the mission’s pioneering spirit.

The Fram2 mission conducted 22 experiments focusing on:

Human Physiology: Including the first X-ray of a human in space and studies on blood flow restriction to mitigate muscle and bone loss in microgravity.

Radiation Exposure: Assessing the effects of increased cosmic radiation encountered in polar orbits.

Biological Studies: Attempting to cultivate oyster mushrooms in space as a potential food source.

Atmospheric Phenomena: Observing aurora-like events such as STEVE and green emissions using high-resolution cameras.

Educational Outreach: The “Fram2Ham” amateur radio project connected with students worldwide, promoting STEM education.

Mission Highlights

Historic Polar Orbit: Fram2 was the first crewed mission to achieve a polar orbit, offering unique perspectives of Earth’s poles.

International Collaboration: The diverse crew underscored the global nature of modern space exploration.

Scientific Contributions: The mission’s experiments provided valuable data for future long-duration spaceflights.

Cultural Significance: Artifacts such as a piece of the original Fram ship’s deck and a Stephen Hawking Medal were carried onboard, bridging past and future explorations.

Fram2’s success demonstrates the potential of private missions to contribute meaningfully to space science and exploration. By achieving a polar orbit, the mission opened new avenues for Earth observation and research. The data collected will inform future missions, particularly those targeting long-duration travel to destinations like Mars. Moreover, the mission’s emphasis on international cooperation and educational outreach sets a precedent for inclusive and globally beneficial space endeavors.

Video credit: SpaceX

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Engineers at NASA’s Marshall Space Flight Center in Huntsville, Alabama, recently completed a test fire campaign of a 14-inch hybrid rocket motor. The rocket motor ignites using both solid fuel and a stream of gaseous oxygen to create a powerful stream of rocket exhaust. Data from the test campaign will help teams prepare for future flight conditions when commercial human landing systems, provided by SpaceX and Blue Origin, touch down on the Moon for crewed Artemis missions.

The hybrid motor was test fired 30 times to ensure it will reliably ignite in preparation for testing later this year at NASA’s Langley Research Center in Hampton, Virginia. This video shows the 28th test, conducted in February, during which the 3D-printed motor fired for six seconds.

Video credit: NASA’s Marshall Space Flight Center

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​Technicians use massive cranes inside the Vehicle Assembly Building at NASA Kennedy’s Space Center in Florida to lift the fully assembled SLS (Space Launch System) core stage vertically 225-feet above the ground from High Bay 2 to a horizontal position in the facility’s transfer aisle. In the transfer aisle, technicians conducted final preparations of the core stage before it was integrated with the completed twin solid rocket booster segments. NASA is implementing a more efficient stacking process to support future missions to the Moon beginning with the Artemis II test flight.

Video credit: NASA