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SpaceX Sends Dragon To ISS But Falcon 9 Rocket Misses Landing Pad (cnet.com)

Posted by BeauHD on from the A-for-effort dept.

On Wednesday, SpaceX successfully sent a Dragon spacecraft to the International Space Station to deliver supplies, but unfortunately it wasn't able to recover the Falcon 9 rocket that launched with it. "The first stage of the Falcon 9 launch vehicle appeared to lose control as it approached Landing Zone 1 at Cape Canaveral," reports CNET. "The live feed from the rocket cut away on the SpaceX webcast, but video from people in the media area at the cape showed the Falcon 9 appearing to regain control before making an unplanned landing in the water rather than ashore at the landing area." From the report: Musk tweeted shortly afterward that cutting the live feed "was a mistake" and shared the full clip of the water landing from the rocket's perspective. The rocket took off from Kennedy Space Center in Florida at 1:16 p.m. local time, a little more than 48 hours after SpaceX sent another Falcon 9 to space from the West Coast on Monday. Dragon's flight to low-Earth orbit was supposed to happen Tuesday, but the mission was pushed back a day to replace some food being sent to the space station for experimental mice living there.

SpaceX had planned to land the first stage of the brand-new Block 5 Falcon 9 rocket at a landing zone ashore at Cape Canaveral, but as the rocket descended toward the cape, the live feed from the booster's onboard cameras appeared to show the craft going into some sort of uncontrolled spin. Musk tweeted that the problem was that a "grid fin hydraulic pump stalled, so Falcon landed just out to sea." Musk also tweeted that the pump that failed didn't have a backup because "landing is considered ground safety critical, but not mission critical. Given this event, we will likely add a backup pump & lines."

4 of 133 comments (clear)

  1. All things considered... by epiphani · · Score: 5, Insightful

    It's nice that a failed landing is news.

    They haven't missed a landing for quite some time now.

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    1. Re:All things considered... by Strider- · · Score: 5, Informative

      The more impressive thing is that it managed to splash down intact, under full control. Due to the stuck hydraulics for the grid fins, it was rolling at a fairly extreme rate. The rocket had already aimed at this spot in the water (it's designed this way) and was actually able to arrest the roll just prior to splash down. After splash down, it remained operational, despite falling onto its side, and successfully safe itself. Apparently it was still in communications and operational while bobbing away in the ocean.

      For the uninitiated, the landing profile has the initial trajectory set with the booster aimed for a region away from the landing pad, be it the one on the ground, or the barge. This is in case of exactly a situation such as this, if something goes wrong during the landing process and the booster loses control authority, it will impact somewhere safe. It's only during the final landing burn (aka the hoverslam) that the booster side slips and changes its trajectory to land in the landing zone.

      So yeah, the system worked exactly as designed, and is fail safe. All in all a successful failure.

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      ...si hoc legere nimium eruditionis habes...
    2. Re:All things considered... by Z80a · · Score: 4, Funny

      Come on, they should be able to get it by now. It's not like this is rocket science.

    3. Re:All things considered... by gman003 · · Score: 4, Insightful

      Soyuz lands on dry earth by using a combination of parachutes and rockets. A series of small solid rocket motors do a "braking burn", igniting one second before landing. And even then, a Soyuz landing is often compared to a road-speed car crash.

      AFAIK no Mars lander used solely parachutes. They all used retrorockets (Viking, Curiosity), or airbags (Mars Express), or both (Pathfinder, Opportunity/Spirit). While Mars has less gravity than Earth, it has even less air, so parachutes are mainly used to get subsonic.

      Further, note that even an empty Falcon 9 booster (~30 tons) weighs substantially more than a Soyuz descent stage (2-3 tons).

      Finally... SpaceX *tried* parachutes first. The first two Falcon 9 launches, back in 2010, had parachutes. It didn't work. Apparently they didn't even survive atmospheric reentry, they were disintegrating before parachutes could be deployed. Fixing that would require retropropulsion for a pre-reentry slowdown burn... and if you've figured that out, and added all the new capabilities required (with all the mass that entails), it makes sense to use that for final landing as well, instead of a separate system. So, three years later, they started those preliminary soft-landing-in-water tests. Took them a year to start getting those to work, then another year to get actual landings to work. And now, it only makes the news when one *doesn't* work. Seems like they made the right call.