SpaceX CRS-5 Mission ISS is Coolest Yet

Elon Musk’s SpaceX is doing another cargo mission for the ISS on Tuesday early morning. This mission has a new twist. The NASA TV broadcasts starts 5am ET. Watch below.

Update: Mission has been canceled for Tuesday. New launch attempt is Friday.

SpaceX is supplying the ISS again on Tuesday. The launch of the SpaceX CRS-5 mission is scheduled for 6:20 a.m. EST Tuesday from Florida. Live NASA TV coverage starts at 5 a.m. This new mission has a new daring twist. SpaceX tries to land the first stage of the Falcon 9 rocket on a ship in the ocean. If successful, Elon Musk‘s SpaceX would have found another way to save a lot of cost delivering stuff into space.

While SpaceX has already demonstrated two successful soft water landings, executing a precision landing on an unanchored ocean platform is significantly more challenging.

SpaceX says that the odds of success are not great – perhaps 50% at best. SpaceX is still trying at this fifty-fifty chance. This is the spirit! This test represents the first in a series of similar tests that will ultimately deliver a fully reusable Falcon 9 first stage.

Returning anything from space is a challenge, but returning a Falcon 9 first stage for a precision landing presents a number of additional hurdles. At 14 stories tall and traveling upwards of 1300 m/s (nearly 1 mi/s), stabilizing the Falcon 9 first stage for reentry is like trying to balance a rubber broomstick on your hand in the middle of a wind storm.

Broadcast live streaming video on Ustream

To help stabilize the stage and to reduce its speed, SpaceX relights the engines for a series of three burns. The first burn—the boostback burn—adjusts the impact point of the vehicle and is followed by the supersonic retro propulsion burn that, along with the drag of the atmosphere, slows the vehicle’s speed from 1300 m/s to about 250 m/s. The final burn is the landing burn, during which the legs deploy and the vehicle’s speed is further reduced to around 2 m/s.

To complicate matters further, the landing site is limited in size and not entirely stationary. The autonomous spaceport drone ship is 300 by 100 feet, with wings that extend its width to 170 feet. While that /4/sound huge at first, to a Falcon 9 first stage coming from space, it seems very small. The legspan of the Falcon 9 first stage is about 70 feet and while the ship is equipped with powerful thrusters to help it stay in place, it is not actually anchored, so finding the bullseye becomes particularly tricky. During previous attempts, we could only expect a landing accuracy of within 10km. For this attempt, we’re targeting a landing accuracy of within 10 meters.

Watch below a test landing of a Falcon 9 rocket on water to see what to expect today. Tune in on Nasa TV to see again space history in the making.