It's taken more than 100 days since its launch, but NOAA's Deep Space Climate Observatory, (referred to as the DSCOVR satellite) has reached its final orbit. Another satellite in orbit, you may think. Big deal. Well, DSCOVR is unique. Other satellites orbit the Earth at a distance of no more than a few hundred miles. DSCOVR is orbiting the sun, at what is known as Lagrange point 1, about a million miles from Earth. There it will be able to study the Sun, monitor the solar wind, the stream of charged particles coming off the Sun, as well as providing early warnings of solar flares and other solar radiation headed for Earth.
So, you may be wondering, what is a lagrange point? Are cattle or ZZ Top involved. No, incidentally, to both. A lagrange point is the point between two gravitational bodies, in this case the Earth and the Sun, where the gravitational pull of each of those bodies will hold an object, in this case the DSCOVR satellite, in balance between the two. So in its current orbit DSCOVR will require very little station keeping course corrections because it is being held in place by the gravitational pull of the Earth on one side and the gravitational pull of the Sun on the other. Get it?
Why do we care about the weather from the Sun? Do you like using your GPS enabled device? Do you like talking to someone on the phone who's more than a few hundred miles away? How about the internet, or for that matter any electrically powered device? Well, the thing is, a solar flare can interfere with any or all of them. If it's intense enough, a solar flare could even fry them.
And let's not forget astronauts. Even aboard the International Space Station, though they do get some protection from the Earth's magnetosphere, astronauts there have a lot less protection than we do down here on the surface.
With enough early warning that a super intense solar flare was on its way from the surface of the Sun, we could make the necessary changes the courses of satellites, or the ISS, or, if necessary, have astronauts bug out and return back to Earth. Advanced warning of solar flares will also be extremely important once we start sending people to the Moon or Mars. Remember that aside from whatever kind of shielding technology we can come up with for them, astronauts out in space, away from the Earth's magnetic field have no protection from solar radiation or solar flares.
DSCOVR is not all about the Sun. While one side of the satellite will be facing the Sun all the time, the other side will be facing Earth. On that side DSCOVR has two NASA Earth-observing instruments that will gather data on things like ozone and aerosol amounts, and changes in what is called the Earth's radiation budget. This is the balance between incoming radiation (largely from the sun) and that which is reflected from Earth. This is important balance it affects our climate.