http://www.forbes.com/sites/bridaineparnell/2015/01/05/spacex-to-test-revolutionary-rockets-sea-legs-in-daring-ocean-landing/
SpaceX has had to abandon its attempted legged rocket landing today, after the launch of its fifth cargo resupply mission to the International Space Station was scrubbed at the last minute. The blast-off was aborted during the final countdown because of "actuator drift", SpaceX explained on its website. "During the terminal count engineers observed drift on one of the two thrust vector actuators on the second stage that would likely have caused an automatic abort. Engineers called a hold in order to take a closer look," the company said. "SpaceX is scrubbed for today and we are now targeting launch on Jan. 9th at 5:09am ET," it added. The private space firm was due to complete the first test of its reusable rocket's precision landing systems after safely delivering the Dragon supply capsule into space. The Falcon 9 booster used in the launch was meant to return through Earth's atmosphere and vertically land on an autonomous spaceport drone ship using hypersonic fins dubbed X-wings to guide it in. While some spacecraft can already be recycled for use again, the most expensive part of space exploration, the rocket, has always been disposable. If SpaceX manages to get a reusable rocket going, it will revolutinise the cost of future missions and bring dreams like manned missions to Mars much closer to fruition. However, the company only puts the odds of the first test being successful at around 50/50. The Falcon 9 has already been tested in soft landings into the ocean, but a precision landing on a gently drifting seacraft will be a totally different ball game. The autonomous spaceport drone ship isn't anchored in place, it uses powerful thrusters to stay steady, meaning it's not entirely stationary. It's also a much smaller target for the 14-storey tall rocket than has ever been tried before. SpaceX admits that so far the rocket's return accuracy has been within about 10km. To land on the spaceport, it needs to be accurate to within 10m. The ship is 300 by 100 feet, with wings that extend its width to 170 feet. But the legspan of the rocket is 70 feet, so it needs to be coming in slow and steady to make it. To achieve that, the rocket will reignite its engines after it separates from the Dragon cargocraft for three burns that will adjust its trajectory and slow it significantly for a final descent of 2m/s from around 1300m/s. The four X-wings, so-called because they're in an X-formation on the rocket, manoeuvre independently for pitch, yaw and roll corrections, which along with engine gimballing, will allow for a more targeted landing. NASA and SpaceX will try the launch again on Friday morning, giving engineers a couple of days to assess the malfunction in the thrust vector control actuator. The new launch window is at 5.09am EDT (10.09am GMT), when you can follow the blast-off live on NASA TV. The attempted rocket landing won't be broadcast by SpaceX, but you can follow the progress on the company website's webcast. _______________________________________________ Medianews mailing list [email protected] http://etskywarn.net/mailman/listinfo/medianews_etskywarn.net
