Slashdot Mirror

← Back to Stories (view on slashdot.org)

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."

21 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.

    --
    .
    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.

      --
      ...si hoc legere nimium eruditionis habes...
    2. Re:All things considered... by dpidcoe · · Score: 2

      To be fair, even the failed landings back when they'd had zero successes were news as well.

    3. 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.

    4. Re:All things considered... by JaredOfEuropa · · Score: 2

      Designing for safety means taking possible mechanical failures into account. Either you provide redundant backups, or have the system fail gracefully (as in this case), or both. So the system did work as designed.

      --
      If construction was anything like programming, an incorrectly fitted lock would bring down the entire building...
    5. Re: All things considered... by Zorpheus · · Score: 2

      As I understood an issue was also that a parachute would pull on the top, while during start the rocket is pushed at the bottom. It would puta different load on the whole rocket, causing deformations each time and require a more stable construction. Rocket assisted landing creates the load on the rocket in the same way as during launch.

    6. Re:All things considered... by ColaMan · · Score: 2

      I expect (justified or not) this event will reinforce that worry.

      I don't know about reinforce, as such. There will already be an engineering estimate about failures in landing based on probability of equipment failure. This actual failure will be another data point to help refine that estimate further.

      If they can recover the booster they can take it apart and get a good idea of what failed exactly and engineer a solution. I've got to wonder how many boosters have been launched over the decades that have had a near-catastrophic issue in flight (eg a crack slowly expanding in the 3 minutes of flight), then fallen into the ocean with that issue never detected.

      --

      You are in a twisty maze of processor lines, all alike.
      There is a lot of hype here.
    7. Re: All things considered... by c6gunner · · Score: 2

      Clearly something clever implemented here to stabilize in the event of the failure of a gridfin

      From watching the footage, it looked like at least one of the fins was still functional enough to counteract the spin somewhat, and the thrusters were firing quite a bit as well. Those both seemed to slow the spin but not stop it. The main engine was gimballing like crazy too but I'm not sure that that would have had much effect.

      What finally stopped the spin almost completely seemed to be the extension of the landing legs. Which makes sense - same principle as a figure skater stretching out or tucking in his arms to increase or decrease rotational speed. Not sure that part of it was "clever" ... it was probably completely unintended ... but it was pretty damn cool.

      Either way I'm amazed. I watched both the onboard video and footage from land ... this is the most exhilarating thing I've seen since the Falcon Heavy double landing.

    8. Re: All things considered... by c6gunner · · Score: 2

      The mars rover which used a parachute weighed 18,000 lbs and the parachute had a 21 meter diameter. Even with those numbers the parachute alone was not enough; it only slowed the descent while the final landing was done with rockets.

      The second stage of the proposed BFR will have a maximum weight of just under 3,000,000 lbs. Wanna do the math on how big your parachute needs to be?

    9. Re:All things considered... by quenda · · Score: 2

      was actually able to arrest the roll just prior to splash down.

      That should not be surprising. When the fin stuck, the rocket was travelling at considerable airspeed. But "just prior to splashdown", with the hoverslam, the velocity was approaching zero, and so also was the spin force from the fin.

    10. Re: All things considered... by c6gunner · · Score: 2

      No, it's not. I've worked on aircraft, and I've experienced emergencies both on the ground and in the air. By no stretch of the imagination is an airplane with a burning engine "working as designed". The safety systems may work as designed to put out the fire, and the redundant systems may be working as designed to prevent catastrophic failure, but the plane as a whole is certainly not working as designed. Even a fucking child looking at it would be able to say "nope, that's not supposed to happen", so I'm flabbergasted why an adult would fail to understand this.

      Even an airplane with a busted microwave oven isn't working as designed, and pilots get really pissy when they can't nuke their coffee. An engine is a weeee bit more important than that.

    11. 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.

    12. Re: All things considered... by froggyjojodaddy · · Score: 2

      Engineer here. I feel like this argument is going nowhere but I'll try nonetheless to give a different perspective

      Your cars brakes fail and you crash into a tree. If the following happened, the system is working as designed:

      - Assuming total failure of the hydraulic braking system, you have a handbrake. In an emergency, you can use that to reduce your speed, but you lose some directional stability
      - You can downshift gears to reduce speed. Directional stability remains unaffected but the rate of speed isn't reduced significantly
      - You can throw the car into reverse or park. Some cars might not even let you do this, older ones will. You'll likely destroy major mechanical components but you'll also slow down pretty quick
      - You crash into the tree. Your airbag, crumple zones etc. work in tandem to protect you. Car is likely a write off but hopefully your speed wasn't so high that you can still survive

      In this context, individual components may have failed, but the system as a whole is working as designed. It's not even semantics, it's being able to step back and look at the system as a whole rather than focusing on individual components. A car is a system that consists of hundreds of components working together. If the fin component failed but other systems kicked in to account for that failure, then the system is indeed working as designed. Others have mentioned this numerous times, it just makes sense..

      Brake engineers don't design their system in a vacuum, they do what they can to ensure brakes don't fail but they'll work with their drivetrain, safety, structural etc. peers to account for the possibility that their system may have a catastrophic failure and then need the other engineers to account for it.

    13. Re:All things considered... by Megane · · Score: 2

      Something that the other replies to your post haven't mentioned is that parachutes are damned hard to control, while a propulsive landing has very good control authority. You can't land the rocket upright when it's floating around like a feather. Have you ever watched a feather drop? It's only good at all for a water landing, and those are right out because sea water is bad for a re-usable spacecraft.

      * Reserve fuel is cheap (compared to the cost of the rocket it's spare change), and it needs to have some anyhow
      * The empty rocket is very light (even one engine can't throttle down enough to maintain a hover)
      * Parachutes are extra weight that isn't needed except when landing. And they're a lot of extra weight. Also, there has been a limit to man-rated space landing parachutes in that only one company has been making all of them since the 1960s. Crew Dragon will be the first to use a new manufacturer, and there is some concern about their process simply because they're new at it.
      * It's not a man rated landing, so the objective isn't to keep humans alive, it's to keep the rocket from breaking
      * And as someone else mentioned, the parachute would put different loads on the frame than during launch, so the whole can would have to be stronger and thus heavier. I'm sure you've crushed a few aluminum soda cans. It's the same thing scaled up, except it's more like a 50cm+ tall soda can, with rocks in the bottom.

      I think the thing that bugs me most is that years after they quickly decided that parachutes were a really dumb idea, we still have naive people suggesting the "obvious" idea that they should use parachutes, as though nobody else was smart enough to consider it. It's not like you can't google for "why doesn't spacex use parachutes" and get a bunch of good answers.

      --
      #naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
    14. Re: All things considered... by Pascoea · · Score: 2

      And you would say that a system which only meets some requirements due to mechanical failure is a system which worked as designed?

      That depends on the requirements and the end result. Specifically in the case of the Block 5 Falcons, yes, the system so far has demonstrated it works as designed.

      No, the rocket didn't work as INTENDED this time, I will give you that, 100%. If it worked as intended it wouldn't be bobbing in the ocean. However, they have proven that their design works, because they have landed their rocket on a pad before. They've met requirement 1. It was also designed to land in the ocean if it isn't safe to land on the landing pad. So yes, the god damn thing did what it was designed to do: fail safely. Requirement 2 met.

      Again; You're intelligent, I've read quite a few of your comments, you are capable of making good arguments. I also get that you are just here to argue, so with that, I say good day.

  2. Re:Just like commercial passenger planes... by DaHat · · Score: 2

    Just like with passenger airplanes, a "water landing" is known as a crash.

    I'm pretty sure the passengers & crew of US Airways Flight 1549 would disagree.

    --
    Help Brendan pay off his student loans
  3. Well... by 93+Escort+Wagon · · Score: 3, Insightful

    "SpaceX Sends Dragon To ISS But Falcon 9 Rocket Misses Landing Pad"

    Better than the other way around.

    --
    #DeleteChrome
  4. Re:Redundant backup pump? by Anonymous Coward · · Score: 3, Interesting

    Actually, that is not far fetched: Sea Dragon.

    Windbourne (moderating).

  5. Re:Crash implies harm by SuperKendall · · Score: 3, Informative

    As far as I understand once they land in saltwater, they are no longer usable. Electronics don't hold up well once exposed to saltwater

    There are quite a lot of non-electronics though that can still be reused.

    From this link: A Falcon 9 first stage is too fragile to just let fall into the water.

    That would be a crash but it not what it did in this case, it still did a burn kind of like it was intending to land., touched down lightly and was fetched fairly quickly.

    From the ACTUAL ARTICLE linked to in the summary, which you probably should have read before you scoured the internet for other random Falcon9 links:

    "Appears to be undamaged & is transmitting data. Recovery ship dispatched," Musk wrote, latter adding: "We may use it for an internal SpaceX mission."

    --
    "There is more worth loving than we have strength to love." - Brian Jay Stanley
  6. Any landing you can walk away from... by Hairy1 · · Score: 3, Informative

    From the article: "Remarkably, it seems SpaceX may still be able to recover the rocket."

    What this means is that it was like a plane landing on water so gently that it could be removed and reflown. What is amazing here is that a major system failure didn't result in a terminal velocity crash into the ocean with the total loss of the vehicle. If this had been a crewed mission:
    a) The crew would have been safe in orbit.
    b) Even if a human were onboard the landing was survivable/soft.

    I say well done SpaceX - even when something goes wrong it goes right.

  7. See for yourself by Bruce+Perens · · Score: 3, Informative

    This really is a case where a picture is worth a thousand words.

    --
    Bruce Perens.