ptfrd

joined 1 year ago
[–] [email protected] 1 points 1 hour ago

Is Katy Perry now the most famous person to have ever been to outer space? Better known than Neil Armstrong is/was?

[–] [email protected] 2 points 22 hours ago* (last edited 22 hours ago)

I still remember the press conference before the first F9 booster reuse. The customer CEO(?) was saying that his team was comfortable, and I think even that the insurance company was comfortable too. So I was fairly confident it would work.

In this case, there's no customer or insurance company giving any high level push-back on any concerns.

One possibility I wonder about is that Musk and/or other senior SpaceX ppl might be wanting to 'double down' on how this is a bold & risk-taking programme, for psychological reasons, in defiance of all the naysayers after the Flights 7 & 8 situation. And thus ignoring the 'critical path' argument, and the fact that the only good risks to take are calculated risks.

Do you think the cost of booster production could be a factor in their decision?

Unsure about this topic in general. My guess is that the raw materials and COTS components are relatively cheap, and that most of the costs are labour. So one uncertainty lies in whether the people would be employed at Starbase regardless of whether they had to build an extra booster or not. And just in general, when we hear dollar figures bandied around, what proportion of those are the true 'marginal'(?) cost.

But ultimately I think yes, now you mention it, cost would've been a significant factor in the decision.

Along with maybe production rate? Maybe they can easily shift existing people & factory space from boosters, to ships. And so the full 'critical path' argument needs to take into account how booster reuse could potentially increase the ship production rate.

[–] [email protected] 2 points 22 hours ago* (last edited 22 hours ago) (1 children)

Well I certainly wouldn't want to launch on an F9 booster on its first flight![1] And NASA recently gave a clear sign that they share that logic to at least some extent.[2] So I'm definitely open to that possibility, for Super Heavy, and maybe SpaceX already believes it.

But as an outsider my guess is that, if nothing else, the 'unknown unknowns' should give us significant concern on the first attempt. I'm guessing a 20% probability that the booster reuse significantly hampers Flight 9.


[1] - Nor on its 2nd actually. My theory is that there could be manufacturing defects in/around the reusability hardware that don't get stressed until after the main stress of the first flight, which the second flight then uncovers. E.g. a landing leg attachment fitted imperfectly causes a crack in the rocket body during the 1st landing, and the crack causes a RUD at max Q during the 2nd flight.

In other words the first section of the bathtub curve might not be as steep as we'd like.

[2] - I think within the last year there was a problem during transport of a brand new F9 booster, and NASA said they were glad to subsequently give it a test flight on a Starlink mission before it was used for a NASA mission.

[–] [email protected] 5 points 1 day ago (1 children)

When next launch? (Flight 8) NET April, “4 to 6 weeks” after Flight 8. (Elon)
When previous launch? (Flight 7)? Booster 15 and Ship 34 launched on 2025-03-06.

I think the numbers in the parentheses need incrementing.

[–] [email protected] 4 points 1 day ago (5 children)

SpaceX has spent several weeks refurbishing, testing, and preparing Booster 14 for its next flight, which is planned to be on Starship’s next flight, Flight 9. The company also announced that 29 out of the 33 engines on the booster are flight-proven,

I wonder if this decision is a mistake. Seems like ship development is on the critical path, and booster development is very much not.

If the estimated increase in risk from the reusing Super Heavy for the first time is substantial, it might be better to delay that until some more progress has been made with Starship.

[–] [email protected] 2 points 3 days ago (1 children)

target UK's first vertical orbital launch

And I think, more to the point, its first successful orbital launch.

And very plausibly (I think), depending on what else happens this year, they could be targeting Western Europe's first successful orbital launch.

[–] [email protected] 3 points 3 days ago (1 children)

even Robert Zubrin

For those who don't know, Zubrin is the gentle & touchy-feely author of joyfully uplifting & empowering self-help books, who also talks about Mars sometimes.

[–] [email protected] 2 points 3 days ago

That’s not how you Federation.

Depends whether the only other two countries to ever achieve human spaceflight are: a single-party state (proto-Borg?), and a gangster nation that occasionally tries to take over a neighbouring nation and steal its children (part Romulan?).

[–] [email protected] 3 points 3 days ago (2 children)

But people keep calling Isaacman "Isaacson", so a more likely mix-up would be Elon Musk's biographer, Walter!

(People including, I think, multiple senators at the nomination hearing. And even Robert Zubrin recently.)

[–] [email protected] 2 points 1 week ago

Hmm, now I'm sincerely hoping that Orlando has a curry restaurant called the Kennedy Spice Center

[–] [email protected] 2 points 1 week ago

Atlas can carry 27 Kuiper satellites

Bit of a coincidence that 27 is also the number of Starlink satellites that Falcon 9 currently seems to be launching (out of Vandenberg) each time.

[–] [email protected] 2 points 1 week ago* (last edited 1 week ago) (1 children)

Saw the headline, then it took me a couple of seconds to decide that this probably wasn't some kind of SpaceX collaboration.

The SpaceX hoppers were actually:

  • grasshopper for testing Falcon 9 landings
  • starhopper - what people call the first vehicle to fly with Raptor engine(s)
 

Steve Stich states at today's Crew-9 news conference that Dragon has a new contingency capability if all 4 parachutes fail; the SuperDracos will ignite prior to splashdown.

The Crew-8 return to Earth will also have this capability.

(He said this about 20 minutes after the start of the stream.)

 

A Youtuber called Ellie in Space claims that a NASA source sent her the following message. It was in response to a question about when NASA knew that the Boe-CFT mission's Starliner vehicle would not be able to undock and return to Earth autonomously without being reconfigured.

So if you want to know when??? Well always, but it wasn't a reasonable consideration to retain the unmanned Starliner capsule software to work in the manned version of the capsule as a contingency. Would you call that a mistake?? Maybe, but let's think about the need to really ever plan to send folks up to space and leave them there with no way to fly home... they would always chose to risk the ride vs having no way home.

No one really considered this very unique and dynamic situation would happen.

Background

I believe this issue was first brought to light by Eric Berger.

Regardless, sources described the process to update the software on Starliner as "non-trivial" and "significant," and that it could take up to four weeks. This is what is driving the delay to launch Crew 9 later next month.

A couple of days later, NASA held a press teleconference in which they emphasized that what was needed was merely a "data load", not a software change. But they indicated timelines that do seem consistent with the "up to four weeks" claim by Berger's source.

My questions

Aren't there several realistic scenarios where you'd want to undock a crew vehicle, without its crew (or at least without them being in a fit state to operate the vehicle), in less than 4 weeeks?

Can Crew Dragon do it? Soyuz?

 

Relevant portion of the video is 18:06 - 22:22.

Key quote: "We'll move a Dragon recovery vessel to the Pacific some time next year, and we'll use SpaceX facilities in the Port of Long Beach for initial post-flight processing".

Although this was revealed in a Crew-9 briefing, it doesn't actually apply to Crew-9.

The announcement has just now been posted to the SpaceX website.

Key excerpts:

During Dragon’s first 21 missions, the trunk remained attached to the vehicle’s pressurized section until after the deorbit burn was completed. Shortly before the spacecraft began reentering the atmosphere, the trunk was jettisoned to ensure it safely splashed down in unpopulated areas in the Pacific Ocean.

After seven years of successful recovery operations on the U.S. West Coast, Dragon recovery operations moved to the East Coast in 2019, enabling teams to unpack and deliver critical cargo to NASA teams in Florida more efficiently and transport crews more quickly to Kennedy Space Center. Additionally, the proximity of the new splashdown locations to SpaceX’s Dragon processing facility at Cape Canaveral Space Force Base in Florida allowed SpaceX teams to recover and refurbish Dragon spacecraft at a faster rate [...]

This shift required SpaceX to develop what has become our current Dragon recovery operations, first implemented during the Demo-1 and CRS-21 missions. Today, Dragon’s trunk is jettisoned prior to the vehicle’s deorbit burn while still in orbit, passively reentering and breaking up in the Earth’s atmosphere in the days to months that follow. [...]

When developing Dragon’s current reentry operations, SpaceX and NASA engineering teams used industry-standard models to understand the trunk’s breakup characteristics. These models predicted that the trunk would fully burn up due to the high temperatures created by air resistance during high-speed reentries into Earth’s atmosphere, leaving no debris. The results of these models was a determining factor in our decision to passively deorbit the trunk and enable Dragon splashdowns off the coast of Florida.

In 2022, however, trunk debris from NASA’s Crew-1 mission to the International Space Station was discovered in Australia, indicating the industry models were not fully accurate with regards to large, composite structures such as Dragon’s trunk. [...]

After careful review and consideration of all potential solutions – coupled with the new knowledge about the standard industry models and that Dragon trunks do not fully burn-up during reentry – SpaceX teams concluded the most effective path forward is to return to West Coast recovery operations.

To accomplish this, SpaceX will implement a software change that will have Dragon execute its deorbit burn before jettisoning the trunk, similar to our first 21 Dragon recoveries. Moving trunk separation after the deorbit burn places the trunk on a known reentry trajectory, with the trunk safely splashing down uprange of the Dragon spacecraft off the coast of California.

 

That's 27 hours from now.

SpaceX is targeting Saturday, July 27 for a Falcon 9 launch of 23 Starlink satellites to low-Earth orbit from Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center in Florida. Liftoff is targeted for 12:21 a.m. ET, with backup opportunities available until 4:21 a.m. ET.

And here is their blogpost, dated 2024-07-25, announcing that the mishap report has been submitted to the FAA, and discussing some of the details.

During the first burn of Falcon 9’s second stage engine, a liquid oxygen leak developed within the insulation around the upper stage engine. The cause of the leak was identified as a crack in a sense line for a pressure sensor attached to the vehicle’s oxygen system. This line cracked due to fatigue caused by high loading from engine vibration and looseness in the clamp that normally constrains the line.

1
submitted 9 months ago* (last edited 9 months ago) by [email protected] to c/[email protected]
 

During tonight’s Falcon 9 launch of Starlink from Space Launch Complex 4 East at Vandenberg Space Force Base in California, the second stage engine did not complete its second burn. As a result, the Starlink satellites were deployed into a lower than intended orbit. SpaceX has made contact with five of the satellites so far and is attempting to have them raise orbit using their ion thrusters.

There's also a tweet saying the same thing in fewer words.

This is the affected mission: Starlink 9-3 launch bulletin

Let's hope it was due to SpaceX pushing the envelope on their in-house Starlink missions in some way, though I have no specific guesses along those lines. Perhaps a manufacturing defect or an operational mistake are more likely to be the leading candidates for the cause.

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