The unmanned Falcon 9 rocket that was supposed to leave Earth on Sunday marks another unmanned cargo mission that's failed to reach the International Space Station (ISS). 

The rocket, built by SpaceX, was carrying supplies for the crew aboard the ISS, including the first docking port designed for future commercial crew capsules, a new spacesuit and a water filtration system. The current water filtration system on the ISS is nearing exhaustion. The astronauts still have stored water that will get them through to October, and food rations for the next four months. 

However this failure, on top of the previous resupply failures, is putting pressure on NASA to send provisions to the ISS astronauts. "This is a blow to us," NASA's William Gerstenmaier said at a press conference, referring to the research and provisions that had been lost in the explosion.

The next resupply mission will be launched by Russia on Friday. There is added pressure on the success of this supply mission, especially since the last Russian Progress 59 rocket launch failed to leave Earth's atmosphere. 

SpaceX's mission actually got off to a good start, with a smooth launch that allowed the rocket to reach around 44 kilometers (27 miles) above Earth while traveling at about 4,700 kilometers per hour (2,920 miles per hour). This is the point where the rocket experiences the maximum aerodynamic stress from moving through the air so quickly. It is also the point that the Falcon 9 spacecraft exploded in a puff of white smoke. SpaceX reported that the pressure in the liquid-oxygen tank got too high in the rocket's upper stage, which is what may have caused the explosion. 

The rocket's computers transmitted over 3,000 channels of data before exploding, which scientists now have to sift through to figure out what went wrong. “If there’s something there, we’re going to find it,” said Gwynne Shotwell, president of SpaceX. We will have to wait for scientists to analyze the data before any firm conclusions can be made, though.

You can watch the successful launch and subsequent explosion here.

^{Falcon 9 rocket Launch, skip to 21 minutes to see the launch. SpaceX.}

The Falcon 9 rockets have been largely successful up until this point, as mentioned in the official NASA report by David Weaver. 

“SpaceX has demonstrated extraordinary capabilities in its first six cargo resupply missions to the station, and we know they can replicate that success. We will work with and support SpaceX to assess what happened, understand the specifics of the failure and correct it to move forward. This is a reminder that spaceflight is an incredible challenge, but we learn from each success and each setback. Today's launch attempt will not deter us from our ambitious human spaceflight program.”  

Elon Musk, the owner of SpaceX, had his 44th birthday on Sunday, the same day as the crash. He summed up the day with a tweet.

@adventFuturist yeah, not the best birthday

— Elon Musk (@elonmusk) June 28, 2015