How does space affect our lives?

The influence of space is pervasive in our lives today, and not only in the developed world. I remember watching the very first transatlantic TV satellite broadcast (Telstar) in the 1960s. Now, every TV news program has video from around the world as it happens. Vast amounts of telephone and computer data are transmitted that way as well. Think about the frequency with which you make use of, or see, these space services:


Trans-oceanic telephone messages can be sent by underwater cable, but cables are expensive and difficult to repair, just like satellites. Also, cables are point-to-point routes. A satellite can receive from or broadcast anywhere. Imagine communications in the Arctic - small communities, long distances. Satellites work better there than cables would. International internet traffic also uses satellites among other methods. TV news is full of video from around the world - even live communications from video-equipped telephones have been used on TV news (during the initial invasion of Iraq, for instance). Businesses also transmit huge amounts of data - think about using a credit card in another country. So every time you use or watch any of these services you are probably linking through space, at least for part of the process. The global economy and information culture is deeply entwined with space.
communication satellites - a brief history
military satellite communications


Do you ever watch weather forecasts on TV? Obviously, many people do. The forecast (even if you get it from other media) is made in part by using satellite observations, but most of the impressive graphics on TV are generated from satellite data. Hurricane warnings based on tracking storms by satellite can help millions of people evacuate as needed, or prepare for the storm. And in the longer term, environmental monitoring satellites help keep track of larger issues such as climate change.
US weather satellite images
Environment Canada - satellite images

global positioning

A relatively new invention, but already becoming essential for navigation, route finding, even inventory tracking, and search & rescue. GPS uses radio signals from a constellation of orbiting satellites to provide very accurate measurements of location anywhere in the world. GPS is turning up in cars, planes, boats, even cell phones, and it's often used on scientific expeditions to locate sites for field work. Russia has its own GPS system called GLONASS, and Europe has just started building its new system called Galileo.
how GPS works
GPS news
And now... GPS in people!

national security

Military and intelligence services use satellite images to see what other nations or groups are doing. They can listen in to electronic communications - this is a big part of what is happenning today in the 'war on terror'. Ships are tracked as they approach a coast to check for smuggling, illegal immigration or security issues. Like it or not, this surveillance is all around us, and a lot of it happens in space. It didn't stop 9/11, but it might prevent the next one... (well, that's the idea anyway). In fact, it has been argued that surveillance helped stabilize the Cold War and keep us from the nightmare of global nuclear war.
space weapons
surveillance satellites

environmental monitoring

The climate change mentioned above is just part of this subject. Satellites can photograph any place on Earth at intervals of a few days or weeks. They are ideally suited to large area surveys. So they monitor natural hazards (floods, forest fires, volcanic eruptions etc. - for instance to warn planes to avoid a volcanic ash cloud or to spot fires in remote areas). They help with environmental inventories - how much forest is logged or burned in the Amazon basin? They can track pollution in water or air over large areas, including oil spills, observe erosion on coasts or river banks, and help enforce regulatory compliance if a resource is being overused.
satellite images
more satellite images
oil spill from space
environment from space

scientific research

Satellites contribute to a lot of scientific research. On Earth this includes climate change, ocean studies and geological exploration. For instance, quite unexpectedly it has been found that excellent maps of ocean floor topography can be made from measuring the height of the sea (a mountain on the ocean floor has enough of its own gravitational attraction to pull water towards it, making a tiny bump in the water). In astronomy and planetary exploration satellites are major contributors... as we will see in a later lecture.
Ocean research from space
Google maps - satellite views
geology from space
Astronaut photography of Earth
Terra remote sensing mission