SpaceX's unmatched streak of perfection with the Falcon 9 rocket is over
arstechnica.com
arstechnica.com
Most importantly, we can tune risk and and reward across the production line; the crewed Falcon 9/Dragon launches are far more conservative than their Starlink + rideshare ones.
Do you have any details about how this is achieved? What changes?
Wider margins of safety. More frequent fallback plana/turnouts. But for the most part: less.
Fewer changes. You go back to a proven model that’s flown more. It won’t have the latest kit. But that’s the point.
> It won’t have the latest kit.
So does the SOTA advances too quickly or not?
By SOTA, do you mean anti-collision kit?
Russia's Soyuz-U has a long history as a reliable booster. They flew it for over four decades, and some blew up, but they never lost a crew. (They did send one crew downrange on a ballistic flight path after a safe abort, which I bet was exciting for everyone concerned [1])
[0] https://en.wikipedia.org/wiki/Human-rating_certification
Falcon had to be built on simple and proven hardware concepts because private commercial space flight was unproven and considered very risky.
Now that SpaceX has proven the impossible is indeed possible to the world many times with reusable rockets, private manned space flight, and an affordable satellite data network—they can raise the capital and field the team needed to build a proper space launch system, which we now know as Starship.
Strongly agree.
The sensors and lightweight compute were not available during World War II.
A guy with a submersible said the exact same thing; he is now in a 1cmx1cmx1cm cube with 4 other people at the bottom of the Atlantic.
Planes came back in WWII. No such luck with upper stages. No Wald hints.
Telemetry doesn’t compensate for the exponential increase in the envelope of relevant parameters in the transition from subsonic flight to orbital mechanics.
SpaceFlightNow is half decent for aerospace.
> Numerous chunks of ice fell away from the rocket as the upper stage engine powered into orbit, but the Merlin Vacuum, or M-Vac, engine appeared to complete its first burn as planned. A leak in the oxidizer system or a problem with insulation could lead to ice accumulation, although the exact cause, and its possible link to the engine malfunction later in flight, will be the focus of SpaceX's investigation into the failure.
> A second burn with the upper stage engine was supposed to raise the perigee, or low point, of the rocket's orbit well above the atmosphere before releasing 20 Starlink satellites [...].
> "Upper stage restart to raise perigee resulted in an engine RUD for reasons currently unknown," Musk wrote...
For Falcon 9 manned launches, there are a whole series of abort modes and we-didn't-get-to-orbit splashdown locations:
https://www.nasaspaceflight.com/2020/05/examining-crew-drago...
It'd be interesting to know where in this mission's flight profile, if it had been manned, the launch director would have ordered an abort. That LOX leaks often lead to explosions is Rocket Science 101.
On Starlink flights they don't have the margin to reach a full circular orbit on a single burn. It's more efficient to achieve an eliptical orbit initially, then coast and perform a second burn at apogee. It's that second burn that proved problematic this time.
Edit: having watched the videos, it would have been clear to SpaceX that they had an oxygen leak right from the start of the second stage burn. So I guess it depends on whether the pressures and flow rates within the engine looked OK. If the leak was external to the engine, then the main risk would be running of out LoX - engines really really don't like ingesting a gas bubble instead of liquid. If it looked like they were getting low on LoX, I'm sure they would have initiated one of the abort modes. Otherwise it's probably safer to continue to orbit. They do have cameras inside the tanks, in addition to all the telemetry - they have occasionally shown then on the livestream.
In a similar vein, I think proper risk acceptance policies shouldn't say "security/safety is our #1 priority", just like a good SLA doesn't guarantee 100% uptime. When you set a 99.9% uptime SLA, make sure you're actually down sometimes. When you want efficient rockets, you have to see some of them crash.
That is true, but it is not directly related to this issue. SpaceX doesn't (can't) reuse second stages. (For now.) The one in question which had the anomaly was a "brand new" second stage.
It is more likely that either this is due to a defect which escaped their QA, or a design issue with a very low probability rolling a nat-1 this time, or some change they introduced not working out as they expected. I would not describe any of those as "aging".
Ok strictly speaking atlas V is not 100% yet. There are 16 more opportunities for failure.
Also, they must ignite without any help from the ground, without any felt gravity (which really helps with pumping fuel and oxidizer).
All that makes the previous run of successful missions all the more impressive.
Every second stage they fire is a brand new one. There are no "flight-proven" second stages. (of course the design is flight proven, but the actual piece of hardware itself is not.)
The other one is since the second stages are not recovered it is much harder to do an after-flight engineering analysis on them. With the first stage SpaceX have most of them back after the flight. That means they can check that all is looking as they expect it. If something with the design is "marginal" in a way they haven't designed them to be marginal they can adjust the design to improve it. With a second stage you can not do that.
Of course this is the default state of every other rocket ever flown. But in spacex's case I would expect the first stage just a tiny bit more reliable than the second stage because of this. (Just a tiny bit, since there is a lot of commonality between the stages)
This raises and interesting question - do you think SpaceX will attempt to recover a Falcon 9 second stage with Starship at some point?
It would be a great technology demonstrator for Starship, and finally gets them a F9 second stage to inspect. Win win.
My childish imagination pictures the proposal as the Agena target vehicle from the Gemini IX test flight. There the fairing did not separate correctly leaving the docking target looking like a hungry space alligator: https://www.nasa.gov/wp-content/uploads/2016/05/5-s66-37966-...
One could imagine the aligator gobling up a drifting second stage. :D It would absolutely not look like that in reality, but if life were a cartoon that is how it would happen. :)
I don't know. Surely it will be a sellable feature of Starship eventually to service and/or return aging sats from orbit. Grabbing an F9 second stage feels like the perfect way to demonstrate that capability. It's not like they're going to have a shortage of Starships returning from orbit in the future.
One of the Shuttle’s selling points was exactly this mission. Apparently it recovered a total of five satellites, three of which were research satellites launched specifically with the expectation of being recovered ahead of time. The other two were mis-launched into the wrong orbit because of a rocket failure. https://space.stackexchange.com/questions/15094/what-satelli...
Of Falcon 9?
Yes, they were aiming for that, and put significant engineering effort towards it before it was deemed too difficult, and instead to focus on Starship, which is a second stage design for re-use from the ground up.
(Same story for catching faring halves in a net on a ship.. they tried and tried, and ended up just making them a little tougher and letting them land in the ocean before fishing them out.
For Starlink and Starshield flights, upper stages are generally configured slightly differently than flights for external customers. These flights are used as an opportunity to explore "optimizations" that, if successful, could be used to lower costs and increase performance for future customer flights. If something doesn't work out, the impact to the Starlink and Starshield constellations is relatively modest and a lesson is learned.
Unfortunately second stage has been a business area where there has been considerable employee turnover and a cluster of mental health episodes and harassment and assault allegations. I hope the people there are and remain safe.
https://arstechnica.com/space/2024/07/europes-first-ariane-6...
Much like saying a sports team’s 10-game winning streak is over does not mean they will never win 10 games in a row again.