Today there are hundreds of satellites orbiting Earth. A portion of those are Global Navigation Satellite Systems (GNSS) like GPS (USA), GLONASS (Russia), Galileo (European Union), and COMPASS or BeiDou (China). But there are many other reasons governments and commercial interests want to put birds in the sky: imagery capture, communications, television broadcasting, weather monitoring, intelligence gathering, and military operations to name a few. Just above our atmosphere lie flocks of high-tech space-traveling robots providing heaps of data and information to people all over the world.
For those of us who really like to geek out on this stuff there is a fantastic website called Spaceflight Now that publishes news and information on what people are launching into space all over the world. You can even look at their launch schedule and see a list of scheduled rocket launches into space, who’s launching them, where they are launching from, and what the rockets are taking into space. On January 29, 2015 the US will launch the Soil Moisture Active Passive (SMAP) satellite which will “measure and map Earth’s soil moisture and freeze/thaw state to better understand terrestrial water, carbon and energy cycles.” Iridium’s commercial communications satellites for sat phones and Wi-Fi in the woods, is launching in June. Spaceports have full schedules of flights headed out of this world in the coming months. It shows two Galileo satellites are scheduled for launch in the first quarter of 2015 and three more satellites will be added to the GPS constellation throughout 2015. The launch log lists all completed space launches from spaceports around the world since 2004. (Source: http://spaceflightnow.com/launch-schedule/)
The US Air Force has maintained the Global Positioning System for decades now which serves as the most robust navigation and geopositioning resource available throughout the world. For a GNSS to provide global coverage it must have at least 24 satellites in orbit. The GPS constellation has more than that and they are constantly upgrading, maintaining, and adding to the constellation. A fantastic resource to learn more about GPS and get official news, tech info, and other relevant resources on GPS is www.gps.gov. If you’re a geek like me block out some time when you visit the site – it’s fascinating!
In recent years there has been a concerted effort to modernize the GPS constellation to open up new frequencies (such as L2C and L5), provide better accuracy and improved signal strength, and to extend the longevity of the system. The table below summarizes details on the various generations of GPS satellites (source: http://www.gps.gov/systems/gps/space/). The current generation being launched are the GPS IIF satellites with the GPS III in the queue to begin launching in 2016. As technology advances and both consumers and professionals continue to expand our daily use of GPS, development of this invaluable resource to society will certainly progress.
The latest modernized GPS IIF satellite successfully launched on October 29, 2014 from the spaceport in Cape Canaveral, Florida and became operational on December 12, 2014. Check out the video of the launch below!