Hacker News Reader

Comment by bilekas | Hacker News Reader

They say high winds and heavy waves were the cause, wouldn't that kind of weather information been a critical condition of launch?

View on HN

It’s also important to note that the landing caused uneven crushing of the landing legs. The result being that the booster has a lean to it and they were unable to fully secure it with the octograbber. The leaning of the booster plus wind and rough seas was required to cause the failure. If the booster was level and fully secured it should have been fine.

The newer boosters have self levelling legs which remove the lean caused by uneven crushing of the landing leg cores.

https://x.com/TurkeyBeaver/status/1739640175183945860?s=20

When I did my one and only parachute jump, they cautioned us hard to jam our legs together for the landing, as any sideways movement would put all the load on one leg, which would break.

Sure enough, one of my friends I went with landed with his legs apart, despite the instructor yelling at him from the ground. He shattered the leg he landed on. (Parachutes weren't as gentle in those days.)

I expect it would be the same problem with the rocket. Any movement sideways when landing means the force is going to be on one leg. I wonder how they deal with that.

You can see that sometimes in the landing footage, the legs are pretty flexible, and they get some help from RCS thrusters at the top of the booster. Plus, as soon as the engine has purged any excess lox/fuel, a robot slides underneath and tries to latch onto several points, which probably helps by bringing the center of mass down.

There's footage online of some of the early landings when the robot had not been implemented, where boosters slid across the barge in part due to landing at a bad angle.

It’s important to note this happened 2 days after the launch. They probably have to be somewhat liberal with what forecasted conditions are allowed during the return trip given the added uncertainty for that time span. Otherwise, they’d be having to scrub launches much more often. Pour one out for B1058 and move on, I think.

The newer boosters with auto-leveling legs would've been able to survive, and even this booster was still chained down wherever octograbber failed to secure.

So it seems like they expected the risk of loss of the booster to be low, it just so happened that this time things went wrong.

They have previously delayed launches due to poor weather at the barge. So if that was the case this time, they would've just postponed, unless I guess they weren't really worried about losing a life leader booster that was apparently too old to be worth retrofitting with autoleveling legs.

They definitely do sometimes delay launches due to bad weather in the landing zone. This could have been a miscalculation, bad forecast, a mistake securing the booster, or just bad luck.

Isn't it crazy that almost all of their competitors dump the whole first stage in the ocean every launch?

Weather at the launch site was probably quite different. I don't know the exact distance, but I assume the landing barges are a good distance downrange.

Falcon 9 is already somewhat sensitive to launch weather conditions, given that it is very long and thin (pencil-like). Scrubs because of inclement weather are not unusual, in contrast to, say, Russian Soyuz, which can take about everything that the Kazakh steppe can throw at it.

If you need to optimize for both the launch weather and the landing site weather, your launch windows are even more limited. At the end of the day, losing an occassional booster isn't a reputational problem; losing the payload would be.

Reply on news.ycombinator.com