satellite
Our space program has gone through many changes over the years. There have been accidents, losses, victories, and amazing strides in both exploration and the vehicles we use to take these trips. One of the biggest goals was to have a space station so that men and women could live and work in space indefinitely…or at least for long periods of time. On June 29, 1995, the American space shuttle Atlantis docked with the Russian space station Mir. This docking formed the largest man-made satellite ever to orbit the Earth…at that time, anyway. We all know that records are meant to be broken.
For a number of years, Russia and the United States had been rivals when it came to the Space Race…as well as many other things, so this joint venture was a really big deal. It was not only about the two rivals working in cooperation together, but it was also the 100th human space mission in American history. It was such a big deal, in fact, that Daniel Goldin, chief of the National Aeronautics and Space Administration (NASA), called it the beginning of “a new era of friendship and cooperation” between the United States and Russia. The docking was also a big deal to people everywhere, with millions of viewers watching on television, Atlantis blasted off from NASA’s Kennedy Space Center in eastern Florida on June 27, 1995.
Just after 6am on June 29, the very excited seven-member crew prepared Atlantis for docking with Mir, as both crafts orbited the Earth some 245 miles above Central Asia, near the Russian-Mongolian border. The moment they spotted the shuttle, the three cosmonauts on Mir began to broadcast Russian folk songs to Atlantis to welcome them. The party was about to begin. Over the next two hours, the shuttle’s commander, Robert “Hoot” Gibson expertly maneuvered his craft towards the space station. This was no easy task. In order to make the docking, Gibson had to steer the 100-ton shuttle to within three inches of Mir at a closing rate of no more than one foot every 10 seconds. Now, I don’t know how fast that would be in miles per hour measurement, but I think these crafts could certainly be damaged by the impact. Precision was key.
Well, the docking went perfectly that day, and by 8am it was completed, and just two seconds off the targeted arrival time, while using 200 pounds less fuel than had been anticipated. Now, that’s what I call success. When docked, Atlantis and the 123-ton Mir formed the largest spacecraft ever in orbit at that time. It was only the second time ships from two countries had linked up in space; the first was in June 1975, when an American Apollo capsule and a Soviet Soyuz spacecraft briefly joined in orbit.
Once the docking was completed, Gibson and Mir’s commander, Vladimir Dezhurov, greeted each other by clasping hands in a victorious celebration of the historic moment. A formal exchange of gifts followed, with the Atlantis crew bringing chocolate, fruit, and flowers and the Mir cosmonauts offering traditional Russian welcoming gifts of bread and salt. After the party, Atlantis remained docked with Mir for five days before returning to Earth. They left two fresh Russian cosmonauts behind on the space station and took the three veteran Mir crew members home in the shuttle. The returning crew members included two Russians and 
Norman Thagard, a US astronaut who rode a Russian rocket to the space station in mid-March 1995 and spent over 100 days in space. This was a United States endurance record…at that time, anyway. This was a great alliance, especially between two former rivals. NASA’s Shuttle-Mir program continued for 11 missions and was a crucial step towards the construction of the International Space Station, which is now in orbit, and is the current largest space craft.
When we think of space, we picture things floating slowly and peacefully along…or at least I do, but the reality is that most things in space are moving quite fast, and along a specific trajectory. While it seems quite chaotic when you think about all the things that are floating around out there, for the most part, it all moves along in a completely organized manner…for the most part.
For things in space to change course, there must be something that interferes with the trajectory…a planet that gets in the way, a new piece of space junk that crosses its path, or a satellite that is falling out of orbit. Even with as much “stuff” as exists in space, these are not common occurrences…or at least not as common as you might think. Nevertheless, on February 10, 2009, two communications satellites…the active commercial Iridium 33 and the derelict Russian military Kosmos-2251…accidentally collided at a speed of 26,000 miles per hour and an altitude of 490 miles above the Taymyr Peninsula in Siberia. That speed puts the collision in the hypervelocity category…in fact, very much so. Hypervelocity is very high velocity, listed as 6,700 miles per hour, or more. At 26,000 miles per hour, this collision more than qualified. That kind of speed is shocking…at least in my mind, and the collision must have been horrific. While there had been other collisions in space, this was the first time a hypervelocity collision occurred between two satellites. Prior to that, all accidental hypervelocity collisions had involved a satellite and a piece of space debris.
The collision occurred at 16:56 UTC, which is the time standard commonly used across the world. The world’s timing centers have agreed to keep their time scales closely synchronized, therefore the name Coordinated Universal Time. The collision destroyed both the Iridium 33 and Kosmos-2251. The Iridium satellite was operational at the time of the collision. Kosmos-2251 had gone out of service in 1995. Kosmos-2251 had no propulsion system, and was no longer actively controlled. Had it been actively controlled, they might have guided it out of harm’s way. NASA initially estimated the debris at 1,000 pieces larger than 3.9, and many smaller pieces, but in reality the US Space Surveillance Network had cataloged 2,000 large pieces by July 2011. They thought the International Space Station, which orbits at about 270 miles below the collision course, was safe, but one piece came within 130 yards at one time, making for a tense few hours.
In the days following the first reports of the incident in 2009, a number of reports of phenomena in the US states of Texas, Kentucky, and New Mexico were attributed to debris from the collision. NASA and the United States Strategic Command, which tracks satellites and orbital debris, did not announce that any debris had 
entered the atmosphere at the time and reported that these phenomena were unrelated to the collision. Still, things like sonic booms heard by witnesses in Kentucky, on February 13, 2009 made no sense in any other scenario. Then, the National Weather Service issued an information statement alerting residents of sonic booms due to the falling satellite debris. The Federal Aviation Administration also released a notice warning pilots of the re-entering debris. However, some reports include details that point to these phenomena being caused by a meteoroid shower rather than debris. A very bright meteor over Texas on February 15, 2009, was mistaken for re-entering debris. By December 2011, many pieces of the debris were in an observable orbital decay, moving towards Earth, and were expected to burn up in the atmosphere within one to two years. By January 2014, 24% of the known debris orbits had actually decayed. In 2016, Space News listed the collision as the second biggest fragmentation event in history, with Kosmos-2251 and Iridium 33 producing respectively 1,668 and 628 pieces of cataloged debris, of which 1,141 and 364 pieces of tracked debris remain in orbit as of January 2016.
Contrary to what was expected, a small piece of Kosmos-2251 satellite debris safely passed by the International Space Station at 2:38 am EDT, Saturday, March 24, 2012, at a distance of just 130 yards. As a precaution, ISS management had the six crew members on board the orbiting complex take refuge inside the two docked Soyuz rendezvous spacecraft until the debris had passed. It was a tense time…not knowing if the debris would hit them or miss them. It is not unusual to see two satellites approach within several miles of each other. In fact, these events occur numerous times each day. It’s a challenge to sort through the large number of potential collisions to identify those that are of higher risk. Precise, up-to-date information regarding current satellite positions is difficult to obtain. In fact, the calculations made by CelesTrak had expected these two satellites to miss by 1,916 feet…not a huge distance, but had it been right, it would have been enough.
Planning an avoidance maneuver with due consideration of the risk, the fuel consumption required for the maneuver, and its effects on the satellite’s normal functioning can also be challenging. John Campbell of Iridium spoke at a June 2007 forum discussing these tradeoffs and the difficulty of handling all the notifications they were getting regarding close approaches, which numbered 400 per week for approaches within three miles for 
the entire Iridium constellation. He estimated the risk of collision per conjunction as one in 50 million…oops!! That was just a little bit off.
This collision and numerous near-misses have renewed calls for mandatory disposal of defunct satellites by deorbiting them, or at the very least, sending them to a graveyard orbit, but no such international law exists at this time. Nevertheless, some countries have adopted such a law domestically, such as France in December 2010. The United States Federal Communications Commission requires all geostationary satellites launched after March 18, 2002, to commit to moving to a graveyard orbit at the end of their operational life. It’s a start.
After the Soviet Union launched Sputnik, the world’s first satellite, on October 4, 1957, inspiring the United States to keep up, or fall behind in the Cold War, the United States launched it’s first satellite on January 31, 1958. That satellite was called Explorer 1, and followed the first two Soviet satellites the previous year…Sputnik 1 and 2. It was the beginning the Cold War Space Race between the two nations. Explorer 1 had mercury batteries that powered the high-power transmitter for 31 days and the low-power transmitter for 105 days. Explorer 1 stopped transmission of data on May 23, 1958 when its batteries died, but remained in orbit for more than 12 years. It reentered the atmosphere over the Pacific Ocean on March 31, 1970 after more than 58,000 orbits. The Explorer 1 payload consisted of the Iowa Cosmic Ray Instrument. It was without a tape data recorder, which was not modified in time to make it onto the spacecraft. The real-time data received on the ground was therefore very sparse and puzzling showing normal counting rates and no counts at all. I’m not sure what the counting was all about, so I guess I’m more confused than the scientists were. The later Explorer 3 mission, which included a tape data recorder in the payload, provided the additional data for confirmation of the earlier Explorer 1 data.
Landsat 1, which was originally named “Earth Resources Technology Satellite 1”, was the first satellite in the United States’ Landsat program. It was the first satellite that was launched with the sole purpose of studying and monitoring the planet. Landsat 1 was a modified version of the Nimbus 4 meteorological satellite and was launched on July 23, 1972 by a Delta 900 rocket from Vandenberg Air Force Base in California. Its orbit was near-polar and it served as a stabilized, Earth-oriented platform for obtaining information on agricultural and forestry resources, geology and mineral resources, hydrology and water resources, geography, cartography, environmental pollution, oceanography and marine resources, and meteorological phenomena. The spacecraft was placed in a sun-synchronous orbit, with an altitude between 564 and 569 miles. The spacecraft was placed in an orbit with an inclination of 99 degrees which orbited the Earth every 103 minutes. The project was renamed to Landsat in 1975.
Landsat 1 had two sensors to achieve its primary objectives…the return beam Vidicon (RBV) and the multispectral scanner (MSS). The RBV was manufactured by the Radio Corporation of America (RCA). The RBV obtained visible light and near infrared photographic images of Earth. It was considered the primary sensor. The MSS sensor manufactured by Hughes Aircraft Company was considered an experimental and secondary sensor, until scientists reviewed the data that was beamed back to Earth. After the data was reviewed, the MSS 
was considered the primary sensor. The MSS was a four-channel scanner that obtained radiometric images of Earth. From launch until 1974, Landsat 1 transmitted over 100,000 images, which covered more than 75% of the Earth’s surface. The RBV only took 1690 images. In 1976, Landsat 1 discovered a tiny uninhabited island 12 miles off the eastern coast of Canada. This island was named Landsat Island after the satellite. The MSS provided more than 300,000 images over the lifespan of the satellite. NASA oversaw 300 researchers that evaluated the data that Landsat 1 transmitted back to Earth. The Landsat 1 satellite sent data back to earth from its orbit until January of 1978 when its tape recorders malfunctioned. After that, it was taken out of service.
These days, being connected to the internet is commonplace. We connect from our computer, laptop, tablet, and even our phone. Many occupations, including the one I am in could not really function without the internet. When the computers go down, we are shut down too. For most of us, the internet is so much a part of our lives, that we simply cannot imagine life without it. Nevertheless, the reality is that until quite recently, there was no internet. I know people who think that might have been a better time, but I disagree. In fact, I think the people who say they think that, really have no idea just how bad that would be, and if they tried it once, they would change their minds quickly. People don’t realize how many things depend on the internet.
The first real idea of information available at our fingertips began to form on October 4, 1957, when the Soviet Union launched the world’s first manmade satellite into orbit. Known as Sputnik, the satellite did not do much. It tumbled aimlessly around in outer space, sending blips and bleeps from its radio transmitters as it circled the Earth. Nevertheless, to many Americans, the one foot diameter Sputnik was proof of something alarming. Up to this point, scientists and engineers in the United States had been designing bigger cars and better television sets, but the Soviets had been focusing on…less frivolous things, and they were going to win the Cold War because of it. Americans saw that information could eventually be transmitted back to the Soviets concerning American military and government secrets. It was the dawning of the age of spy satellites.
Sputnik’s launch, brought about the era of science and technology in America. In an effort to keep up, schools began teaching subjects like chemistry, physics and calculus. The government gave grants to corporations, who invested them in scientific research and development. The federal government formed new agencies, such as the National Aeronautics and Space Administration (NASA) and the Department of Defense’s Advanced Research Projects Agency (ARPA), to develop space-age technologies such as rockets, weapons and computers. Of course, the computer didn’t do nearly as much as it does these days, and it was the size of a small house. In 1962, a scientist from M.I.T. and ARPA named J.C.R. Licklider proposed a solution to this problem. His proposal 
was a “galactic network” of computers that could talk to one another. Such a network would enable government leaders to communicate even if the Soviets destroyed the telephone system. Then came “packet switching.” Packet switching breaks data down into blocks, or packets, before sending it to its destination. That way, each packet can take its own route from place to place. Without packet switching, the government’s computer network, which is now known as the ARPAnet, would have been just as vulnerable to enemy attacks as the phone system. At least now computers did more, but they were still big.
In 1969, ARPAnet delivered its first message. A “node-to-node” communication from one computer located in a research lab at UCLA, to the second located at Stanford. The message “LOGIN” was short and simple, and it crashed the ARPA network. Wow!! Things really are different today. The Stanford computer only received the note’s first two letters. By the end of 1969, just four computers were connected to the Arpanet. During the 1970s the network grew steadily. In 1971, it added the University of Hawaii’s ALOHAnet, and two years later it added networks at London’s University College and the Royal Radar Establishment in Norway. As packet-switched computer networks multiplied, it became more difficult for them to integrate into a single worldwide “Internet.” By the end of the 1970s, a computer scientist named Vinton Cerf had begun to solve this problem by developing a way for all of the computers on all of the world’s mini-networks to communicate with one another. He called his invention “Transmission Control Protocol,” or TCP. Later, he added an additional protocol, known as “Internet Protocol.” The acronym we use to refer to these today is TCP/IP. One writer describes Cerf’s protocol as “the ‘handshake’ that introduces distant and different computers to each other in a virtual space.”
Cerf’s protocol transformed the Internet into a worldwide network. Throughout the 1980s, researchers and scientists used it to send files and data from one computer to another. In 1991 the Internet changed again. That year, a computer programmer in Switzerland named Tim Berners-Lee introduced the World Wide Web…an Internet that was not simply a way to send files from one place to another, but was itself a “web” of information that anyone on the Internet could retrieve. Berners-Lee created the Internet that we know and use today. Since then, the Internet has changed in many ways, and will likely continue to change as time goes on. 
In 1992, a group of students and researchers at the University of Illinois developed a browser that they called Mosaic, later known as Netscape. Mosaic offered a user-friendly way to search the Web. It allowed users to see words and pictures on the same page for the first time and to navigate using scrollbars and clickable links. Then Congress decided that the Web could be used for commercial purposes. Companies developed websites of their own, and e-commerce entrepreneurs began to use the Internet to sell goods directly to customers. These days, social networking sites like Facebook have become a popular way for people of all ages, including me, to stay connected. Today, almost one-third of the world’s 6.8 billion people use the Internet regularly.
