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3 days ago
- Science
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How does Isro save satellites from collision?
The Indian Space Research Organisation (Isro) saved its satellites from collision 11 times in 2024 by performing collision avoidance manoeuvres. read more India saved its satellites from collision 11 times in 2024, according to Isro's Indian Space Situational Assessment Report (ISSAR) report. The Indian Space Research Organisation (Isro) in the report said that it saved six satellites in the low-Earth orbit (LEO) and four in the geostationary orbit (GEO) from collision. The Isro also said that it prevented the Chandrayaan-2 orbiter from a planetary collision. The Isro said that an orbit maintenance manoeuvre was originally scheduled for Chandrayaan-2 on November 26, 2024, but it was advanced to Nov. 11 to mitigate conjunctions with Nasa's Lunar Reconnaissance Orbiter (LRO), which were predicted to occur on Nov. 15-16. STORY CONTINUES BELOW THIS AD The Isro prevents such collisions by performing collision avoidance manoeuvres (CAM). These are planned changes in a spacecraft or a satellite's trajectory in space to avoid running into some other space object, which can be a body in the space, satellites, or debris from other satellites. The Isro performs such manoeuvres after conducting Space Situational Awareness (SSA) assessments to see whether an object in the space is going to be in the close vicinity of a spacecraft or a satellite. Such objects can include space debris, natural objects like asteroids and meteoroids, and energy and particle flux. ALSO READ: From a slow start to a concrete policy, how India has shaped space research with hits and misses Isro's System for Safe and Sustainable Operations Management (IS4OM) functions as the nodal entity for all space sustainability efforts, including SSA assessments and to improve compliance with internationally-recognised guidelines on the long-term sustainability of outer space activities. Isro in the report said that it conducts analyses to predict close approaches by other space objects to Indian space assets. In case of any critical close approach, CAMs are carried out to rule out or minimise the collision risk. Last year, the Isro said that the Combatant Space Operations Center of the US Space Command had issued more than 53,000 alerts Isro's Earth-orbiting satellites. These alerts were analysed using more accurate orbital data from flight dynamics and 11 collision avoidance manoeuvres were conducted — as mentioned above. STORY CONTINUES BELOW THIS AD The Isro released the following graph to show the CAMs conducted in recent years: Cumulative number of collision avoidance manoeuvres (CAMs) performed for Earth-orbiting satellites of Isro till 2024. (Photo: Isro) The number of CAMs was less in 2024 compared to the previous year because improved close approach analysis methodology with larger conjunction screening volume and usage of more accurate ephemerides helped to meet collision avoidance requirements by adjusting orbit maintenance manoeuvres on several occasions and avoiding exclusive CAMs, according to Isro. Last year, the Isro said, all manoeuvre plans, including those of the CAMs, were subjected to close approach risk analysis to rule out any potential close approach with other neighbouring space objects imminently after the manoeuvres. In doing so, the report said that 89 manoeuvre plans were revised to avoid post-manoeuvre close approaches with other space objects for LEO satellites and on two occasions manoeuvre plans were revised such for GEO satellites.
Yahoo
13-03-2025
- Science
- Yahoo
Dead Athena moon lander seen inside its crater grave from lunar orbit (photos)
When you buy through links on our articles, Future and its syndication partners may earn a commission. We now have shots of the Athena moon lander's final resting place. Athena, the second lunar lander from Houston company Intuitive Machines, tipped over during its touchdown on March 6, ending up on its side within a small crater near the moon's south pole. This orientation prevented the lander's solar panels from capturing enough sunlight, and Intuitive Machines declared Athena dead on March 7. (The company's first moon lander, named Odysseus, also tipped over during its historic February 2024 touchdown but was able to operate for longer on the lunar surface.) Athena beamed home a few shots of its surroundings before giving up the ghost. And we now have views of the lander and its crater grave from on high, courtesy of NASA's sharp-eyed Lunar Reconnaissance Orbiter (LRO). On March 7, LRO captured a gorgeous oblique photo of Athena and its landing site — the Mons Mouton region, about 100 miles (160 kilometers) from the lunar south pole. Then, three days later, the probe snapped another pic, which provided a closer look at Athena on the shadowed floor of a 65-foot-wide (20 meters) crater. Related: Private Intuitive Machines moon lander declared dead after falling on its side in crater at the lunar south pole Athena's mission, known as IM-2, was supported by NASA's Commercial Lunar Payload Services (CLPS) program, which puts agency science instruments on private moon landers. The experiments on board Athena — and the ride-along robots, like Colorado company Lunar Outpost's MAPP rover and Intuitive Machines' hopping spacecraft "Grace" — didn't get their planned science time on the lunar surface. But the lander did survive for a while before its batteries died. And its brief life could help pave the way for future work in the area, which is thought to harbor large stores of water ice, Intuitive Machines said. "This southern pole region is lit by harsh sun angles and limited direct communication with the Earth," the company wrote in a March 7 mission update. "This area has been avoided due to its rugged terrain, and Intuitive Machines believes the insights and achievements from IM-2 will open this region for further space exploration." Related stories: — Lunar Reconnaissance Orbiter: A guide to NASA's venerable lunar orbiter — The moon: Everything you need to know about Earth's companion — There's lots of water on the moon for astronauts. But is it safe to drink? Athena hit the gray dirt just four days after another CLPS-supported lander, Firefly Aerospace's Blue Ghost, touched down in the moon's northern hemisphere. LRO, which has been studying the moon from lunar orbit since 2009, has also captured photos of Blue Ghost. The Firefly lander remains healthy and is expected to continue operating until March 16, when the sun sets over its locale.
Yahoo
13-03-2025
- Science
- Yahoo
Secrets in the shadows: What lunar eclipses teach us about Earth
When you buy through links on our articles, Future and its syndication partners may earn a commission. Ready for a show? On the night of March 13 into the early hours of March 14, a total lunar eclipse will occur as the moon moves into the Earth's umbra, or shadow, turning the bright white lunar surface an eerie red. (It's no wonder this phenomenon is nicknamed the "blood moon.") But eclipses aren't only an entertaining astronomical show — they have practical implications for science, too. While eclipses might've inspired fear in many ancient civilizations, they also inspired scientific discovery. "In ancient Greece, philosophers realized that the Earth is round because the shape of the Earth's shadow on the moon is always curved during an eclipse," Christine Shupla, education manager at the Lunar Planetary Institute, told "This is perhaps one of the best-known discoveries from lunar eclipses." Today, lunar eclipses still teach us a lot about our planet, especially our atmosphere. The reddish color associated with total lunar eclipses occur because sunlight travels through our atmosphere and refracts towards the moon — the atmosphere scatters shorter-wavelength colors like blues and greens, allowing reds and oranges to reach the moon. It's the same reason why sunsets and sunrises feature those beautiful warm tones. But the moon isn't always the same color during a total lunar eclipse. "How dark and what color the moon appears will tell us more about the changing composition of our own atmosphere," says Shupla. "For instance, sometimes the moon appears reddish, but other times it is much darker and brown-grey, for instance, after a large volcanic eruption has occurred." We're also able to learn a bit about the moon during lunar eclipses, too, especially from lunar spacecraft. NASA's Lunar Reconnaissance Orbiter (LRO) "has made observations during prior eclipses, mainly focusing on how quickly the surface temperature changes once the moon is in the Earth's shadow," Noah Petro, LRO project scientist, told "Some of the observations have shown that the surface doesn't cool down uniformly. That is, there are differences in surface properties around small craters that are only due to changes in the upper few centimeters of the surface, which is something we normally wouldn't detect." LRO won't be taking active measurements during this eclipse, but it'll still be affected by it. The solar-powered spacecraft won't encounter direct sunlight during the eclipse, which lasts hours, affecting its power supply. "We put the spacecraft into an optimal orbit so that we fully charge our battery prior to the eclipse, turn off the instruments so we don't drain the battery, and then wait until the battery is recharged before turning the instruments back on," says Petro. "Think of it like putting your phone in low-power mode if you are away from a charger for an extended time." Related stories: — What time is the 'Blood Moon' total lunar eclipse this week?— Where will the 'Blood Moon' total lunar eclipse be visible this week? — Lunar eclipses 2025 — When, where & how to see them As more spacecraft land on the moon and begin their scientific operations — and, perhaps, as humans return to the moon through NASA's Artemis program — we'll likely continue to learn more about lunar eclipses and their effect on the moon itself. In the meantime, for us Earth-bound viewers, it's just time to enjoy the show! "Unlike a solar eclipse, which can only be observed by those people along the path that the moon's shadow makes on the Earth, a lunar eclipse can be seen by everyone who can see the moon at that time — everyone on the same side of the Earth," says Shupla. For this March 2025 lunar eclipse, more than a billion people will be able to see the moon turn red. And keep a sharp eye out — you never know what you might see during the eclipse. "In 2019, observers saw the flash of light from an impact on the moon during an eclipse," says Shupla. Catch up with the latest lunar eclipse news and events with our lunar eclipse live blog.
Yahoo
11-03-2025
- Science
- Yahoo
There's a total lunar eclipse coming. How will these 2 solar-powered moon probes survive the darkness?
When you buy through links on our articles, Future and its syndication partners may earn a commission. When the moon falls into Earth's shadow Thursday night into Friday (March 13-14), observers will be treated to views of a "blood moon" total lunar eclipse. But given that lunar spacecraft are solar-powered, how do they survive when they're cut off from the sun? For NASA's Lunar Reconnaissance Orbiter (LRO), which has been orbiting the moon since 2009, it will be time to batten down the hatches. "LRO's science instruments and some components not needed by the spacecraft will be powered off during the total lunar eclipse," Noah Petro, project scientist for the LRO mission at NASA's Goddard Space Flight Center, said in an interview with The danger is to LRO's battery. The spacecraft is solar-powered and spends the daylight portion of its roughly two-hour orbit around the moon using its solar arrays to charge its onboard battery, which it then relies on while on the nightside of the moon. However, NASA revealed that by 2018, the efficiency of LRO's battery had already degraded to 70% as a result of continual charging. During the March 13-14 total lunar eclipse, LRO will be in darkness — either on the moon's nightside or in Earth's umbral shadow — for 5 hours, 48 minutes. That's a relatively long time, but Petro is confident that LRO's battery can keep the spacecraft alive. "Before entering the eclipse, we will have charged the battery to its maximum capacity," he said. To prevent too great a drain on its power, every scientific instrument on the spacecraft is being shut down. During an eclipse, the temperature inside the spacecraft can drop to 23 degrees Fahrenheit (minus 5 degrees Celsius), but for the spacecraft's wide-angle camera, which is less protected, it can feel as cold as minus 22 F (minus 30 C). So steps will be taken beforehand to make sure everything is as rosy as possible. "Because being in darkness also cools the satellite, we will heat the instruments and spacecraft prior to the eclipse," Petro said. "This ensures minimal added power draw from heaters during the eclipse while maintaining spacecraft components within normal operating temperatures and the instruments well above survival limits." The precautions taken for a lunar eclipse haven't always been quite this drastic. During previous eclipses, LRO was able to keep one instrument switched on. Called Diviner, it is a radiometer that detects thermal emissions from the lunar surface to study how the surface warms and cools over the course of a lunar day. The idea behind keeping it switched on during a lunar eclipse was to study how the lunar surface cools while in Earth's shadow, which provides information about the composition and size distribution of material in the lunar regolith, which is made up of rocks, small particles and dust. The size and composition of the rocks affect how quickly they cool. "Diviner's measurements during prior eclipses, particularly of targeted regions, allows for insight into the uppermost surface of the moon," Petro said. During the total lunar eclipse on Oct. 8, 2014, Diviner specifically observed a crater called Kepler and a lunar nighttime "cold spot." In particular, cold spots are areas around some craters where Diviner had found unusually cool nighttime temperatures. In addition to determining the size distribution of the material ejected from the crater during the impact, Diviner found that the "cold spot" was 18 F (10 C) warmer than the surrounding material. This suggests that the vertical layering of material within the lunar regolith may be more complex than previously thought, to allow it to radiate heat away at a different rate from its surroundings. LRO isn't the only active lunar mission. Firefly Aerospace's Blue Ghost, the second private mission to soft-land on the moon, touched down in Mare Crisium on March 2 as part of NASA's Commercial Lunar Payload Services program. Related: Private Blue Ghost lander spotted on the moon by NASA lunar orbiter (photo) Blue Ghost is carrying 10 NASA experiments designed to investigate the surface of the moon. Like LRO, it is solar powered. Blue Ghost is designed to last only during the daytime, which is about two weeks on the slowly rotating moon. Indeed, Blue Ghost landed in time to see the sunrise. Once the sun has set, the lander's batteries will power down, its heaters will switch off, and the cold of lunar night will probably kill it by mid-March. But will Blue Ghost survive that long? Sunset from Blue Ghost's landing site comes on March 16, but the total lunar eclipse is two days before that and will plunge the lander into shadow. The mission can survive several hours into lunar night on battery power alone. The lunar eclipse will last 6 hours, 3 minutes overall, but only 65 minutes of that will be in totality, under what's called the dark umbral shadow. The rest of the eclipse will take place in the penumbral shadow, where some sunlight does reach the surface. Indeed, the Firefly Aerospace team is so confident that Blue Ghost will survive the eclipse that they intend to take high-resolution images of the event from the lunar surface while the lander is in Earth's shadow. In other words, on the moon, Blue Ghost will see a total solar eclipse! So, as you look up at the moon while Earth's shadow moves over it on the night of March 13-14, spare a thought for those lonely, vulnerable space probes that must battle through the darkness to survive.
Yahoo
11-02-2025
- Science
- Yahoo
Did Covid lockdowns really cause temperatures on the moon to drop?
When you buy through links on our articles, Future and its syndication partners may earn a commission. Scientists have been arguing about a curious topic recently: Did temperatures on the moon dip due to the world's Covid-19 lockdown? Last year, a pair of researchers claimed that the shockwaves of the shutdown could be felt as far as the moon, causing a slight dip in lunar surface temperatures. Now, a new paper disputes that finding, saying that it's not possible to definitively attribute that drop to the reduction of global emissions associated with the lockdown. After several studies revealed that the shutdown had a significant effect on air quality around the world, two researchers in India investigated whether the atmospheric changes could have had an effect on the moon. "We thought it would be a rare opportunity to investigate the effects of [Covid] on the moon," Durga Prasad, a scientist at the Physical Research Laboratory (PRL) in Ahmedabad and lead author of the study, told by email. Prasad and study co-author G. Ambily, also of PRL, reviewed data collected from a variety of spots near the lunar equator by NASA's Lunar Reconnaissance Orbiter (LRO). They discovered that surface temperatures dropped in the evening by 8 to 10 degrees Kelvin between April and May 2020. The duo attributed this drop to the global shutdown at the height of the pandemic. As is often the case in science, not everyone agrees with their conclusions. "The process in reality is very complex, and I believe not all factors were considered," Shirin Haque, a researcher at the University of the West Indies in Trinidad, told by email. Haque and her colleague presented a dissenting view of the original data. "That is what may have led them to the conclusion they arrived at." Related: Dramatic effect of coronavirus lockdowns seen from space As Covid-19 emerged at the dawn of 2020, China, the country of origin, was the first to shut down some of its cities. Over subsequent months, other countries followed suit, leading to a worldwide shutdown after the World Health Organization declared the outbreak to be a pandemic in March. By June, countries had begun relaxing their grip as the world descended into what many would call "the new normal.' Several independent studies revealed that the shutdown had a significant effect on Earth's atmosphere — a conclusion backed up by anecdotal evidence. Photographs of major cities such as Los Angeles revealed unusually clear skies during the spring of 2020. As people stayed home, the greenhouse gases created by car and air travel were dramatically reduced. When sunlight reaches Earth, part of it is absorbed into the surface while the rest is reflected as radiation. The heated planet also emits its own radiation. Both are affected by greenhouse gases trapped in the atmosphere. Together, this emission creates a slight glow known as terrestrial radiation, or Earthshine. During the lunar day, the moon feels the energy of both the sun and Earth. At night, with its back to the sun and its face pointed at day-time Earth, the nearside lunar surface feels only the warmth from our planet. Previous studies have shown that Earthshine can affect the lunar nighttime temperature. The process of terrestrial light reflecting off the moon was first suggested by Leonardo da Vinci. "When aerosols are decreased, less solar radiation is scattered back to space," Prasad said. The researchers turned to LRO's Diviner Lunar Radiometer Experiment, an instrument designed to measure temperatures on the lunar surface. They found six sites on the nearside of the moon with similar roughness and brightness values, all near the equator, to minimize how much radiation directly hit the moon. The temperatures were taken between 10 p.m. and 4 a.m. local time on the moon in order to minimize the amount of leftover heat the surface had absorbed during the day. Temperatures were taken from 2017 to 2022 — multiple years on either side of the lockdown peak of April to May 2020. "Six months is a good span of data for interpretation," Prasad said. The results were published last September in the journal Monthly Notices of the Royal Astronomical Society (MNRAS). Related: New moon glows with 'Earthshine' in incredible time-lapse photo series But it's not an open-and-shut case. Haque was sent the article by a friend, who wanted to know if the finding was true. "My initial reaction was one of surprise, and I assumed it was published in a suspect forum — but it was in a leading astronomy journal," she said. Haque began to discuss the new result with other astronomers. "Everyone's initial reaction was one of disbelief and suspicion," she said. So she and colleague William Schonberg, of the Missouri University of Science and Technology, decided to look into the new results, as "we both found it too incredible to be true." Their findings were also published in MNRAS, in January 2025. Whether Earthshine heats up the lunar surface was not in doubt — that process had been documented by earlier research. Haque and Schonberg also observed the drop in surface temperature over the nights between April and May 2020. What they question is the role of the worldwide shutdown in that cooling. They pointed to the timing of the temperature drop. While the Prasad-Ambily paper highlights the measurements taken between April and May, the Haque paper notes that the temperature starts to drop in 2019, before the worldwide lockdown took place. The drop is gradual, they argue, not sudden. Prasad disagrees. "Schonberg and Haque have claimed that the temperature began dropping earlier by visually analyzing the trendline" on a figure in the Prasad-Ambily paper, he said. That trendline is plotted only for visual clarity and is an averaged interpolation of all observations. What is more important, he said, is the clusters of data during April and May. "It is not a decrease but a sudden drop," Prasad said. "The authors have misunderstood/misinterpreted the representation of our data." In their research, Schonberg and Haque noted that there was no information on how the trendline itself was obtained, which they called "unfortunate." Furthermore, they pointed out, "if the trendline was potentially misleading, then they should not have included the trendline." The new paper also pointed to another significant temperature drop in 2018, one that Prasad and Ambily had also noted. That drop clearly wasn't related to the Covid shutdown, and the authors suggested that it could be significant. Prasad emphasized that his and Ambily's paper only analyzed the period during the lockdown and was not concerned with the earlier cooling. "Our analysis is particularly focused only on the April-May period of all the years, since it was the strict lockdown period in 2020," he said. "We believe that it is not possible, at this time, to state with any amount of certainty, that the temperature dip we all observed as being the result of decreased human activity on Earth during the Covid-19 lockdown," Shonberg said. "We believe it's a matter of correlation being confused with causation." Related: Air pollution levels will bounce back as Covid-19 restrictions loosen, scientists say RELATED STORIES: — The moon: Everything you need to know about Earth's companion — No, the coronavirus didn't come from outer space — New moon glows with 'Earthshine' in incredible time-lapse photo series Prasad and Ambily stand behind their interpretation of the data. "We never mentioned that the observation is only due to Covid lockdown," he said. "As we did not find any other reason supporting this unique observation, we have attributed that Covid lockdown seems to be the most plausible reason." Haque and Schonberg said they appreciate that their colleagues are open to other causes. However, they said that the very title of the original article — "Effects of Covid-19 global lockdown on our moon" — appears to negate that uncertainty. "The title of their work does not appear to convey the sense of uncertainty that they would seem to prefer that readers take from their article," Haque and Shonberg said. The conclusion also appears unambiguous, claiming that the dip in lunar temperature "clearly" relates to a global lockdown, they added. Prasad emphasized that future studies are needed to better understand the results of their observations. "In the absence of any other concrete explanation for the observation of anomalous dip coinciding exactly with that of the strict lockdown period, Covid 19 lockdown is likely to be the only cause," he said.
