Satellite technology is impressive. But scientists fear there might be too many filling up our atmosphere. Here’s why.
Category: satellites – Page 3
An international team of scientists using observations from NASA-German satellites found evidence that Earth’s total amount of freshwater dropped abruptly starting in May 2014 and has remained low ever since. Reporting in Surveys in Geophysics, the researchers suggested the shift could indicate Earth’s continents have entered a persistently drier phase.
From 2015 through 2023, satellite measurements showed that the average amount of freshwater stored on land—that includes liquid surface water like lakes and rivers, plus water in aquifers underground—was 290 cubic miles (1,200 cubic km) lower than the average levels from 2002 through 2014, said Matthew Rodell, one of the study authors and a hydrologist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “That’s two and a half times the volume of Lake Erie lost.”
During times of drought, along with the modern expansion of irrigated agriculture, farms and cities must rely more heavily on groundwater, which can lead to a cycle of declining underground water supplies: freshwater supplies become depleted, rain and snow fail to replenish them, and more groundwater is pumped.
On December 5, 2024, the European Space Agency (ESA) achieved a milestone in space exploration with the successful launch of its Proba-3 mission, which aims to create artificial solar eclipses. This revolutionary mission could provide groundbreaking insights into the Sun’s mysterious atmosphere, the corona. By creating artificial eclipses, the two Proba-3 spacecraft will work together to block the Sun’s light, allowing scientists to observe its outer layers like never before. These solar eclipses will provide a close-up view of the corona for the first time, unlocking secrets that were previously beyond our reach.
The Proba-3 mission is built around a remarkable concept: two satellites, the Occulter and the Coronagraph, will fly in precise formation, separated by a distance of 500 feet. This configuration will allow the Occulter to block the Sun’s light and cast a shadow onto the Coronagraph, creating an artificial eclipse in orbit. By mimicking the conditions of a natural solar eclipse, scientists will be able to observe the Sun’s corona for extended periods, up to six hours at a time, far surpassing the fleeting moments provided by natural eclipses on Earth.
This level of precision, described by ESA as “down to the thickness of a fingernail,” is unprecedented in space exploration. The spacecraft rely on a suite of advanced technologies, including GPS, star trackers, lasers, and radio links, to maintain their exact positioning autonomously. This capability allows the spacecraft to operate as though they were a single, integrated observatory, delivering the optical performance required for such ambitious science objectives.
What do motion detectors, self-driving cars, chemical analyzers and satellites have in common? They all contain detectors for infrared (IR) light. At their core and besides readout electronics, such detectors usually consist of a crystalline semiconductor material.
Such materials are challenging to manufacture: They often require extreme conditions, such as a very high temperature, and a lot of energy. Empa researchers are convinced that there is an easier way. A team led by Ivan Shorubalko from the Transport at the Nanoscale Interfaces laboratory is working on miniaturized IR detectors made of colloidal quantum dots.
The words “quantum dots” do not sound like an easy concept to most people. Shorubalko explains, “The properties of a material depend not only on its chemical composition, but also on its dimensions.” If you produce tiny particles of a certain material, they may have different properties than larger pieces of the very same material. This is due to quantum effects, hence the name “quantum dots.”
WASHINGTON — Varda Space Industries secured a $48 million contract from the U.S. Air Force Research Laboratory to test military payloads on the company’s reentry capsules.
A California-based startup focused on in-space manufacturing, Varda Space developed a factory-in-orbit spacecraft — a compact, 120-kilogram satellite engineered to produce high-value materials such as pharmaceuticals in zero-gravity conditions. The materials are returned to Earth in a capsule built with advanced thermal protection materials developed by NASA to withstand reentry.
The four-year deal with AFRL, announced on Nov. 26, leverages Varda’s W-Series reentry capsules as platforms to test payloads at hypersonic speeds. The spacecraft are built on Rocket Lab’s Photon satellite bus.
Starlink has received the green light from the US authorities to launch its direct-to-cell satellite service, but there are still a number of technical hurdles to overcome before it can actually be made fully available to users.
The US Federal Communications Commission (FCC) has now authorised Starlink, SpaceX’s Internet service provider, to roll out its direct-to-cell satellite service. The idea is to be able to make phone calls directly via satellite, wherever you are, especially in so-called dead zones not currently served by a regular cellular network, such as deserts, mountains or oceans. Indeed, the Starlink constellation of low-earth orbit satellites has the potential to offer worldwide cellular coverage.
Despite this authorization, there are still a number of hurdles to overcome before this service can see the light of day, as the FCC has not responded favorably to all Starlink’s requests. For example, in order to offer optimal telephony and live video services, it will be necessary to exceed current radio emission limits.
A plan to use millions of smartphones to map out real-time variations in Earth’s ionosphere has been tested by researchers in the US. Developed by Brian Williams and colleagues at Google Research in California, the system could improve the accuracy of global navigation satellite systems (GNSSs) such as GPS and provide new insights into the ionosphere.
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A GNSS uses a network of satellites to broadcast radio signals to ground-based receivers. Each receiver calculates its position based on the arrival times of signals from several satellites. These signals first pass through Earth’s ionosphere, which is a layer of weakly-ionized plasma about 50–1500 km above Earth’s surface. As a GNSS signal travels through the ionosphere, it interacts with free electrons and this slows down the signals slightly – an effect that depends on the frequency of the signal.
Data from NISAR will improve our understanding of such phenomena as earthquakes, volcanoes, and landslides, as well as damage to infrastructure.
We don’t always notice it, but much of Earth’s surface is in constant motion. Scientists have used satellites and ground-based instruments to track land movement associated with volcanoes, earthquakes, landslides, and other phenomena. But a new satellite from NASA and the Indian Space Research Organization (ISRO) aims to improve what we know and, potentially, help us prepare for and recover from natural and human-caused disasters.
The NISAR (NASA-ISRO Synthetic Aperture Radar) mission will measure the motion of nearly all of the planet’s land and ice-covered surfaces twice every 12 days. The pace of NISAR’s data collection will give researchers a fuller picture of how Earth’s surface changes over time. “This kind of regular observation allows us to look at how Earth’s surface moves across nearly the entire planet,” said Cathleen Jones, NISAR applications lead at NASA’s Jet Propulsion Laboratory in Southern California.
New findings suggest our galaxy’s evolutionary history is strikingly different from all the others.
Researchers have found that there’s something highly unusual about the Milky Way that sets it apart from galaxies which, on a surface level, appear similar.
As detailed in three recent papers published in The Astrophysical Journal, a team of researchers examined a mountain of data as part of the Satellites Around Galactic Analogs (SAGA) survey, which was dedicated to comparing the Milky Way to 101 other galaxies that are similar in mass.
The distinction is technical but significant, the researchers say: they found that the Milky Way has surprisingly few smaller satellite galaxies compared to its peers — and some of them have mysteriously stopped forming new stars.
Two satellites in Proba-3 mission expected to be launched on Wednesday in India and will work in tandem to study sun’s corona.