If you have followed the works of Italian astronomer, physicist, and engineer Galileo Galilei, you would probably be well versed with the events of 1609 in Venice, when Galileo wrote a letter to his brother confirming the existence of a spyglass instrument which “represent(s) an object that is, for example, fifty miles away, as large and near as if it were only five.” Though the authenticity of the letter is often debated, what really isn’t in debate is the fact that Galileo had amazed the Venetians by letting them see the ships out at sea as close as if they were in the port itself—and it would actually be hours before these ships actually entered the port. A lot of time may have passed since, and a lot of proverbial water may have flown under the proverbial bridge, but the fundamentals haven’t really changed. Enter satellites, which are also about looking for things at a great distance—except that these orbit around the earth and are meant to look at everything on earth itself.
These satellites are used to uplink television signals from broadcasters and downlink them to the pizza-sized satellite dish installed on the roof of your home. These satellites are the backbone for all the global positioning system (GPS) navigation, including the good old Google Maps in your phone. These satellites provide meteorologists with the data for understanding weather on a local and a global scale. These satellites provide critical data on ocean currents and temperatures. These satellites can log the changes in size and movement of glaciers. All by constantly photographing the earth’s landmass. And this is just a fraction of what satellites orbiting earth can do.
According to the Index of Objects Launched into Outer Space which is prepared by the data from the United Nations Office for Outer Space Affairs (UNOOSA), there are 4,987 satellites in the Earth’s orbit at the beginning of this year—which is a 2.68 percent increase compared with last year.
Not all satellites are the same, however. There are low-earth orbits (LEO), which tend to fly just a few hundred kilometers above the surface of the earth. Since their orbit is small, they tend to loop around earth quite quickly. A lot of the LEO satellites tend to follow the polar orbit, which means they pass above both the north and south poles many times a day. Then there are the medium-earth orbits (MEO) and are semi-synchronous. These are usually placed around 20,000km above the earth’s surface, and pass the same points on the equator multiple times a day. Then there are the geostationary satellites, also known as high-earth orbits (HEO). These are synchronized with the earth’s rotation and are in a way parked at an exact point above the earth and matches the earth’s rotation. These satellites are usually used for communication and broadcasting, as well as for weather since they need to constantly gather information about weather pattern changes at specific locations. Each satellite has a different size rating since it is built for specific tasks, and different orbit lives, a factory that is also dictated by the amount of fuel or battery power it has.
Perhaps the most crucial task that they do is terrain mapping and photography, which is equally relevant for civilian and military purposes. The latter gaining even more significance in these tense times when India and Pakistan are squaring off after the Indian Air Force targeted terrorist camps inside Pakistan. In case you are wondering about how the Indian Air Force would know about the exact location of these camps inside Pakistan, it would be because of satellites. Any of these satellites, placed to gather information, would do the job. That is true for just about any country which has a satellite in space—nothing stops them from photographing territories of another country. However, governments and militaries around the world tend to have regulations about what resolution and detailing for the images that any satellite clicks, will be available for public viewing. Basically, what you see on Google Earth, for instance.
India has been focusing on satellites for the military, and the launch of the GSAT-7A satellite in December last year perhaps testifies that change in strategy. This is built exclusively for the Indian Air Force and the Indian Army. The GSAT-7A will help the military interlink different ground radar stations and airbases as well as Airborne Warning and Control System (AWACS) aircrafts such as the DRDO AEW&CS and Beriev A-50 Phalcon. The cost of the GSAT-7A is estimated to be around Rs 6 billion to Rs 8 billion and has an estimated life of 9 years. Back in 2013, ISRO had launched the GSAT-7 satellite, its first satellite dedicated for the Indian military. At the ORF-Kalpana Chawla Space Policy Dialogue last year, Lt. Gen. PM Bali, Director General, Perspective Planning, Indian Army had observed that there is now a greater need for space technology when it comes to the national security framework.
A lot of privately owned companies are also using their expertise to get into orbit. The San Francisco based satellite operator Spire was started by an Austrian, a Canadian and a Belgian— Peter Platzer, Joel Spark and Jeroen Cappaert respectively. The company makes LEO nanosatellites, and currently has 72 satellites in orbit. Their satellites collect maritime data (map trade routes, track ships, monitor illegal movements and piracy), aviation data (identify, track and predict aircraft traffic) and also weather data. Spire says none of its satellites can be used for imaging.
Then there is BlackSky, which currently has plans to put 60 satellites into space by the end of the year. The company’s satellites are available for tracking movement of different modes of transport, checking for illegal maritime activities in the high seas, providing humanitarian relief and critically, also for what BlackSky calls “securing troops and borders”. BlackSky says they provide color imagery captured by their satellites, at a resolution of one meter (1 square meter is considered as 1 image pixel). This is where global rules dictate what sort of image resolutions can be made public. These rules also dictate what you see on Google Maps, for instance. For example, in the US, satellite companies cannot release high-resolution images of Israel and the territories under its control, as part of the Kyl-Bingaman Amendment in the National Defense Authorization Act passed in 1997. Companies such as Google source the images from a variety of commercial and public sources, and the content they get is defined by the guidelines these sources have to operate within.
At this moment, Elon Musk’s SpaceX holds the approval of the United States Federal Communications Commission (FCC) to put as many as 7,518 satellites into orbit, with the aim to provide internet coverage from space—this is called the Starlink constellation. Apart from that, three other companies, Telesat, LeoSat, and Kepler Communications have also received approvals for 11,778 and 140 satellites respectively. In December, SpaceX launched 64 satellites in what is labeled as a record-breaking mission. The US Air Force has already awarded SpaceX a $28.7 million contract to test interconnectivity with conformal antenna arrays installed on aircraft. That is perhaps why NASA has raised an alarm already—the space agency says that an estimated 99 percent of these satellites will have to be taken out of orbit within five years after they complete service. Else there is the risk of collisions, which will lead to uncontrolled space debris, among other issues. Space, truly, is the next frontier.