What goes up must come down, and sometimes the ways in which gravity wins aren’t pretty. A SpaceX rocket sending supplies to the International Space Station exploded in the skies off the coast of Florida this morning, and weather radar was able to track what was left of the rocket as it fell into the Atlantic Ocean.
The SpaceX rocket, carrying 4,000 pounds of supplies for the three astronauts aboard the I.S.S., exploded about two minutes after takeoff from Cape Canaveral, Florida. Details about the explosion are scarce right now, with company CEO Elon Musk saying that preliminary data indicated that there was an “overpressure event” with the upper stage liquid oxygen tank before the failure.
About half an hour after the failed launch, the Doppler weather radar site in Melbourne, Florida, began picking up some returns about 45 miles to the northeast of the launch site. The first sign of debris showed up on radar around 10:45 AM EDT, and steadily grew stronger for the next hour.
There were thunderstorms in the area (which likely had no effect on the rocket launch) at the time, and it’s easy to mix up which returns are precipitation and which returns are the blown-up remains of years of hopes and dreams smoldering its way to a watery grave. Thanks to recent upgrades in technology, we can determine what’s rain and what’s rocket by looking at a product called “correlation coefficient.”
New technology recently added to weather radar sites across the country allows them to not only see the intensity and direction of precipitation, but the size and shape of objects it detects. Objects that are mostly uniform in shape (like raindrops) have a high correlation coefficient, while objects that widely vary in size and shape (such as tornado debris, or in this case, rocket debris) have a very low correlation coefficient.
The above radar animation shows correlation coefficient between about 10:20 AM—around the time of the explosion—and 11:45 AM. The reddish/purple colors show thunderstorms over land, while the patch of blue over the water off the coast of New Smyrna Beach shows the variasize rocket debris as it aims whichever sharks are swimming to shore to feast on swimmers this afternoon.
One of the many reasons Cape Canaveral was chosen as the main rocket launch site in the United States is that rockets are over nothing but ocean as they soar downrange into space, so when they explode—and some will explode—the weighty, flaming remains don’t destroy entire towns, since this is generally considered to be a bad thing.
The good news, however, is that rockets failing in a spectacular fashion over the open water allows us to gawk at weather radar and watch the debris fall into the ocean. Doppler weather radar is able to detect just about anything in the beam’s way—usually we only care about precipitation, but radar can often show us the location and movement of swarms of bugs, flocks of birds, smoke from fires, debris swirling around in tornadoes, airplanes, and even highway traffic or trains speeding down railroad tracks if the beam gets inverted on cool mornings.
Weather radar was able to track the debris of the Space Shuttle Columbia after it broke apart in the atmosphere over Texas, and more recently, radar in Delaware tracked the toxic cloud of smoke that resulted from the spectacular explosion of Orbital Sciences’ Antares rocket seconds after launch on Wallops Island, Virginia.
[Images: Gibson Ridge]