Satellite
A satellite is a moon, planet or machine that orbits a planet or star. For example, Earth is a satellite because it orbits the sun. Likewise, the moon is a satellite because it orbits Earth. Usually, the word "satellite" refers to a machine that is launched into space and moves around Earth or another body in space. Earth and the moon are examples of natural satellites. Thousands of artificial, or man-made, satellites orbit Earth. Some take pictures of the planet that help meteorologists predict weather and track hurricanes. Some take pictures of other planets, the sun, black holes, dark matter or faraway galaxies. These pictures help scientists better understand the solar system and universe. Still other satellites are used mainly for communications, such as beaming TV signals and phone calls around the world. A group of more than 20 satellites make up the Global Positioning System, or GPS. If you have a GPS receiver, these satellites can help figure out your exact location. The bird's-eye view that satellites have allows them to see large areas of Earth at one time. This ability means satellites can collect more data, more quickly, than instruments on the ground. Satellites also can see into space better than telescopes at Earth's surface. That's because satellites fly above the clouds, dust and molecules in the atmosphere that can block the view from ground level. Before satellites, TV signals didn't go very far. TV signals only travel in straight lines. So they would quickly trail off into space instead of following Earth's curve. Sometimes mountains or tall buildings would block them. Phone calls to faraway places were also a problem. Setting up telephone wires over long distances or underwater is difficult and costs a lot. With satellites, TV signals and phone calls are sent upward to a satellite. Then, almost instantly, the satellite can send them back down to different locations on Earth. Satellites come in many shapes and sizes. But most have at least two parts in common - an antenna and a power source. The antenna sends and receives information, often to and from Earth. The power source can be a solar panel or battery. Solar panels make power by turning sunlight into electricity. Many NASA satellites carry cameras and scientific sensors. Sometimes these instruments point toward Earth to gather information about its land, air and water. Other times they face toward space to collect data from the solar system and universe.
Most satellites are launched into space on rockets. A satellite orbits Earth when its speed is balanced by the pull of Earth's gravity. Without this balance, the satellite would fly in a straight line off into space or fall back to Earth. Satellites orbit Earth at different heights, different speeds and along different paths. The two most common types of orbit are "geostationary" (jee-oh-STAY-shun-air-ee) and "polar." A geostationary satellite travels from west to east over the equator. It moves in the same direction and at the same rate Earth is spinning. From Earth, a geostationary satellite looks like it is standing still since it is always above the same location. Polar-orbiting satellites travel in a north-south direction from pole to pole. As Earth spins underneath, these satellites can scan the entire globe, one strip at a time. Actually, they can. NASA and other U.S. and international organizations keep track of satellites in space. Collisions are rare because when a satellite is launched, it is placed into an orbit designed to avoid other satellites. But orbits can change over time. And the chances of a crash increase as more and more satellites are launched into space. In February 2009, two communications satellites - one American and one Russian - collided in space. This, however, is believed to be the first time two man-made satellites have collided accidentally. Sputnik 1 was the first satellite in space. The Soviet Union launched it in 1957. NASA has launched dozens of satellites into space, starting with the Explorer 1 satellite in 1958. Explorer 1 was America's first man-made satellite. The main instrument aboard was a sensor that measured high-energy particles in space called cosmic rays. The first satellite picture of Earth came from NASA's Explorer 6 in 1959. TIROS-1 followed in 1960 with the first TV picture of Earth from space. These pictures did not show much detail. But they did show the potential satellites had to change how people view Earth and space. NASA satellites help scientists study Earth and space. Satellites looking toward Earth provide information about clouds, oceans, land and ice. They also measure gases in the atmosphere, such as ozone and carbon
dioxide, and the amount of energy that Earth absorbs and emits. And satellites monitor wildfires, volcanoes and their smoke. All this information helps scientists predict weather and climate. The information also helps public health officials track disease and famine; it helps farmers know what crops to plant; and it helps emergency workers respond to natural disasters. Satellites that face toward space have a variety of jobs. Some watch for dangerous rays coming from the sun. Others explore asteroids and comets, the history of stars, and the origin of planets. Some satellites fly near or orbit other planets. These spacecraft may look for evidence of water on Mars or capture close-up pictures of Saturn's rings.
On Thanksgiving (Nov. 28), China launched another satellite into Earth's orbit, capping off a very busy month for the country. Gaofen-12, a new Earth observation satellite, flew to space from the Taiyuan Satellite Launch Center in northern China's Shanxi Province, according to state news source Xinhua. The rocket successfully took off at 7:52 a.m. Beijing time on Nov. 28, which is 6:52 p.m. EDT or 2352 GMT Nov. 27. The satellite launched on a Long March-4C rocket, which marks the 320th flight for this type of rocket. Footage from Chinese television station CCTV showed the rocket flawlessly lifting off into a cloudy sky, flames spitting out from
beneath the booster. The footage also shows engineers and other officials closely monitoring the rocket's progress into orbit. "I hereby announce that the launch mission is successful," said an unnamed engineer, according to CCTV's translation. NASA-NOAA satellite finds development of tropical cyclone 06A Imagery from NASA-NOAA's Suomi NPP satellite showed that a tropical depression in the Arabian Sea has consolidated and organized despite facing wind shear. Tropical Depression 06A is now Tropical Cyclone 06A. The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP provided a visible image of 06A that revealed powerful storms were northwest of the center of circulation, but the storm was able to strengthen despite the harsh environmental conditions. The center of circulation is apparent in the VIIRS image as a small area of circulation located southeast of the bulk of clouds and showers. In general, wind shear is a measure of how the speed and direction of winds change with altitude. Tropical cyclones are like rotating cylinders of winds. Each level needs to be stacked on top each other vertically in order for the storm to maintain strength or intensify. Wind shear occurs when winds at different levels of the atmosphere push against the rotating cylinder of winds, weakening the rotation by pushing it apart at different levels. In the case of Tropical Cyclone 06A, southeasterly winds are pushing the bulk of the storm's clouds to the northwest. The Joint Typhoon Warning Center or JTWC in Pearl Harbor, Hawaii noted, "A fully exposed low level circulation center in animated multispectral satellite imagery. Strong (20-30 knot/ 23 to 34.5 mph /32 to 55.5 kph) vertical wind shear is offsetting good poleward outflow and warm (28 to 29 degrees Celsius/82.4 to 84.2 degrees Fahrenheit) sea surface temperature, hampering intensification." Tropical cyclones require sea surface temperatures of at least 26.6 degrees Celsius (80 degrees Fahrenheit) to maintain strength or intensify, so the warmer sea surface temperatures are allowing 06A to maintain its strength. JTWC noted that at 10 a.m. EST (1500 UTC) on Dec. 3, that 06A had maximum sustained winds near 35 knots (40 mph/65 kph). 06A was located near latitude 7.1 degrees north and longitude 57.4 degrees east. It was about 784 nautical miles east-northeast of Mogadishu, Somalia.
It is moving to the northeast, however, and the track will slowly turn west southwestward as a subtropical ridge (elongated area of high pressure) builds back in to the north. Tropical Cyclone 06A is forecast to make landfall in east central Somalia on Dec. 6 as a tropical storm. Tropical cyclones and hurricanes are the most powerful weather events on Earth. NASA's expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting. Orbion partners with US Department of Defense on small satellite propulsion tech Michigan-based in-space propulsion startup Orbion is working with a major new partner: The U.S. Department of Defense (DOD). Orbion has secured a research contract from the U.S. Air Force Research Laboratory's Propulsion Directorate, specifically aimed at helping the DOD "enhance resiliency of U.S. systems in space." Basically, it sounds like that will boil down to seeing how Orbion's propulsion technology can be applied to DOD satellites when used in larger constellation form, to provide those satellites with the ability to move propulsively while in orbit, and to do so in a way that can scale cost-effectively. In a press release announcing the news, Orbion CEO Brad King says that volume is a strategy when it comes to fortifying U.S. systems in space against potential foreign attack. "One way to increase the resilience of space systems is to improve our nation’s ability to build and deploy small satellites in large numbers at low costs,” said King in a statement, “Orbion is developing mass-production techniques to build propulsion systems for commercial customers. With this research contract we are investigating how or if our manufacturing processes must be modified to meet DOD requirements.” It's true that in the past, the U.S. and other international powers with access to space have mostly focused on large, expensive, singular pieces of orbital hardware as their strategic assets. Shifting to the small satellite constellation approach currently being pursued by a number of private companies definitely has advantages in terms of redundancy and replaceability. Orbion's entire business proposition as a startup is that it's applying massproduction to in-space thrusters, which will bring down costs and make their
technology accessible to a much wider range of potential clients, and practical for application in small satellite design. The DOD may not have the same budget-constraint issues as a cash-strapped satellite startup, but long-term cost savings that also comes with a tactical advantage is a hard bargain to pass up. NASA satellite finds crashed Indian Moon lander Vikram A NASA satellite orbiting the Moon has found India's Vikram lander which crashed on the lunar surface in September, the United States space agency has said. NASA made the announcement on Monday, releasing an image taken by its Lunar Reconnaissance Orbiter (LRO) that showed the site of the spacecraft's impact (September 6 in India and September 7 in the US). A version of the picture was marked up to show the associated debris field, with parts scattered over almost two dozen locations spanning several kilometres. More: In a statement, NASA said it released a mosaic image of the site on September 26 (but taken on September 17), inviting the public to compare it with images of the same area before the crash to find signs of the lander. The first person to come up with a positive identification was Shanmuga "Shan" Subramanian, a 33-year-old IT professional from Chennai, who told AFP that NASA's inability to find the lander on its own had sparked his interest. This image shows the Vikram Lander impact point and associated debris field. Green dots indicate spacecraft debris (confirmed or likely). Blue dots locate disturbed soil, likely where small bits of the spacecraft churned up the regolith. "S" indicates debris identified by Shanmuga Subramanian [Credits: NASA/Goddard/Arizona State University] "I had side-by-side comparison of those two images on two of my laptops... on one side there was the old image, and another side there was the new image released by NASA," he said, adding he was helped by fellow Twitter and Reddit users. "It was quite hard, but (I) spent some effort," said the self-professed space nerd, finally announcing his discovery on Twitter on October 3. NASA then performed additional searches in the area and officially announced the finding almost two months later.
"NASA has to be 100 percent sure before they can go public, and that's the reason they waited to confirm it, and even I would have done the same," said Subramanian. "It was quite clear that Vikram had hard-landed on the lunar surface... That it failed so close to the lunar surface is a testament to the skill of the very young Chandrayaan 2 (Moon Vehicle 2) team," said Pallava Bagla, author of Reaching for the Stars: India's Journey to Moon, Mars and Beyond. Space is indeed a risky business and not meant for the faint-hearted, acknowledging failure is a stepping stone to success. Pallava Bagla, senior science journalist "But that the Indian space agency took nearly two months to acknowledge the failure is an astonishing fact," he told Al Jazeera. "Space is indeed a risky business and not meant for the faint-hearted, acknowledging failure is a stepping stone to success." Blasting off in July, emerging Asian giant India had hoped with its Chandrayaan-2 mission to become just the fourth country after the US, Russia and regional rival China to make a successful Moon landing and the first on the lunar south pole. The main spacecraft, which remains in orbit around the Moon, dropped the unmanned lander Vikram for a descent that would take five days, but the probe went silent just 2.1 kilometres (1.3 miles) above the surface. Days after the failed landing, the Indian Space Research Organisation said it had located the lander but had not been able to establish communication.
A small Japanese satellite scheduled for launch Friday on a Rocket Lab Electron booster will release hundreds of colorful sky pellets to fall into the atmosphere next year, creating an artificial meteor shower that could be visible to millions. The satellite, built and owned by Tokyo-based Astro Live Experiences, will launch into a 250-mile-high (400-kilometer) polar orbit to prepare for next year’s sky spectacle. On-board thrusters will help target re-entry over a specific region for the artificial shooting stars. ALE has not announced the location or exact time for the meteor shower demonstration. “I’m excited for the upcoming launch of our second satellite, ALE-2,” said Lena Okajima, ALE’s chief executive. “I’m delighted to have an earlier launch date than I expected. With this launch, we are a step closer to realize the man-made shooting star.” The 165-pound (75-kilogram) ALE-2 satellite measures 2 feet by 2 feet by 2.6 feet (60 x 60 x 80 centimeters). It’s the biggest of seven spacecraft scheduled for launch on Rocket Lab’s 10th Electron rocket Friday The launch window opens at 2:56 a.m. EST (0756 GMT) Friday at Rocket Lab’s privately-run launch base on New Zealand’s North Island. Liftoff time is set for 8:56 p.m. local time in New Zealand. The launch of the ALE-2 satellite follows the deployment of ALE’s first microsatellite earlier this year during a flight of a Japanese Epsilon rocket.