The now iconic ‘Blue Marble’ photograph of Earth was captured on December 7, 1972 as the crew of the final Apollo mission headed towards the Moon. It was captured at a distance of about 28,000 miles and became one of the most widely distributed images in human history.
EPIC sits aboard the Deep Space Climate Observatory (DSCOVR). This observatory is operated by a joint partnership between NASA, NOAA and the U.S. Air Force, and is designed to maintain constant solar wind monitoring.
Thanks to DSCOVR’s unique orbiting location, NASA’s EPIC instrument constantly views the sunlit portion of the Earth. NASA will use EPIC to monitor daily changes of clouds, ozone and even vegetation. With a four megapixel CCD camera and telescope, EPIC can take images at a resolution between 6.2 and 9.4 miles according to Adam Szabo, a DSCOVR project scientist.
How EPIC always faces a sun-lit Earth
DSCOVR sits at Lagrangian point 1, or L1. Lagrangian points are orbital positions where a small object can maintain a stable position relative to two larger bodies only by gravity. If you place a spacecraft at just the right spot between the Sun and Earth, gravity from Earth cancels out some of the pull of the Sun.
That right spot is about one million miles away from Earth. Here’s an image from NOAA showing DSCOVR at L1.
An EPIC Moon photobomb
Because DSCOVR sits nearly one million miles away from Earth, it (rarely) gets a chance to snap this series of incredible images.
Scientists expect the Moon and Earth to get together for photographs like this only about twice a year.
As I mentioned above, DSCOVR’s primary mission is monitoring the Sun. It will measure magnetic field intensity and direction along with the distribution of incoming ions and electrons in the solar wind plasma. These measurements will combine to tell scientists plasma velocity, density and temperature.
DSCOVR will also be used to detect CME’s just before they encounter Earth. These observations will improve our understanding of CME’s and help predict the timing of impacts.
Check out the video below to learn more about DSCOVR’s mission. And the EPIC website for daily images of the Earth.