The Great Ongoing Space Exploration Thread

That would explain all the Spaghetti.

I haven’t even looked for the original paper, but I would be surprised if they used which way the spirals are winding up to determine which way they’re rotating. Especially since it’s possible to use radial velocity instead.

Someone in the article said the asymetry could be caused by the rotation of our galaxy, which they usually ignore for these kinds of studies. That definitely says they used radial velocities.

They check the edges. One edge will be moving away (red shift)
and the other will be moving towards us (blue shift).

I don’t think they did that for this study. I looked at the paper and as far as I can tell, they only found this effect in galaxies that were at a high redshift. And then used how the galaxies looked to see which way they were rotating. While there are some galaxies that rotate backwards (i.e. spiral arms are not trailing), they’re rare, so the authors assumed all galaxies in the study were rotating forwards.

But the fact that the effect only shows up at high z indicates to me that there’s probably some systematic error going on.

What I was getting at is that afaik the spin axis of galaxies are every random orientation possible. Even if you know which way each galaxy is spinning, how do you possibly assign an overall angular momentum?

Finally:

We might be a little spoiled if a 2-day delay deserves a “finally.” 90% of Space Shuttle missions had a scrub. STS-35 was delayed by more than 6 months!

The “finally” refers to the 9 months they were in space: it was supposed to be 8 days; then it was supposed to be 6 months.

That’s fair. You might be Going with Boeing, but you might not be coming back with them…

This is cool:

Every lunar eclipse is actually a solar eclipse as well… if you’re on the moon.

Angular momentum of the galaxies is not an issue here.

However, I just read an article in Universe Today that analyses the paper better than I could.

tl;dr: Two possibilities:

  1. the universe has a net rotation
  2. the motion of the Earth through the galaxy produces a Doppler Effect that makes some galaxies brighter. The ones that are brighter tend to be those that rotate the opposite direction of our galaxy, since the opposite rotation combined with the Solar System’s motion increases the Doppler Effect.

Damning article today claiming that SpaceX is botching quality control on Starship upper stages, and that Starship cannot meet the payload goals that the entire program was predicated on:

But we were promised pies in the sky!

Well, we are getting pies in the sky. If you use the Punkin’ Chunkin’ definition of “pie”. :grin:

That last one blowed up real good.

I sense some bias here, this is a gross misrepresentation:

“after seven failed launch attempts, Starship has yet to achieve a complete orbit of Earth at the lowest possible altitude.”

I stopped reading there. They either didn’t do their research, or outright lied.

Oh definitely biased; they have nothing but good to say about the 1960s heyday of space socialism a.k.a. Apollo/Saturn, and at the end they tack on a typical “capitalism is the eevulz” criticism of the whole project. But that doesn’t invalidate that Starship hasn’t hit a run yet. And far more worrying is the contention that the upper stage has lost so much performance that it won’t meet the payload goals it was intended for. Upper-stage weight gain is a killer for any attempt at reusability. It’s why the Shuttle had the compromise design it did of NOT attempting to enclose fuel tanks within the orbiter.

Interesting article but it failed to explain the iterative nature of the Starship test program which is nothing like NASA’s approach which is what the article is comparing it to. A poor article really though there are some valuable takeouts. I think objectivity when it comes to projects involving Elon Musk is going to be severely lacking in some sections of the media.

The author’s latest articles are:
This Is Just Pathetic (about Tesla)
Tesla Can, And Will, Fall Further
Starship Was Doomed From The Beginning
Starship Is In Deep Trouble
This Is How Tesla Will Die
Trump Just Sabotaged The US
Tesla Is Dying, And Polestar Wants To Kill It
Musk Stealing A $2.4 Billion FAA Comms Contract Is Far More Horrifying Than You Think.
Tesla Is So Screwed
SpaceX Has Finally Figured Out Why Starship Exploded, And The Reason Is Utterly Embarrassing

I think the guy might be a teeny tiny bit obsessed.

Yeah. The flights were always meant to be short of a full orbit. They still reached orbital speeds.

I recently learned that Yuri Gagarin’s orbital flight did not quite go around the globe–it landed west of the launch site, and if you count the time spent at orbital velocity, it was much less than a full orbit. No matter–that doesn’t take away from the achievement at all, because the hard part of getting to orbit is the speed. Not completing a full circle is just not that relelvant.

As I said, the guy’s definitely biased; for example he criticizes loss of telemetry without explaining how a tumbling rocket is supposed to maintain antenna alignment. But is he wrong about Starship not paying due diligence to prevent pointless, useless failures that quality control and inspection should have caught? And did Musk really admit that Starship currently could only boost half the payload originally planned?

What does “originally planned” mean? It’s true that version 1 only lifts 40-50 tons to orbit, although really the number is zero tons since version 1 could not take payload at all–it has no payload mounting system or anything else. It’s a pathfinder model.

Version 2 should bring 100+ tons to orbit, and version 3 200+ tons. And those have been planned for a while, which they’ve made no secret about:
Imgur

I’m not a fan of saying they had to “admit” anything since they had always planned an iterative development approach. It’s entirely possible that version 1 had more mass growth than they expected, or that Raptors didn’t achieve the desired thrust initially, or whatever–but they had always intended to fly what they had, see what works, and iterate from there. I highly doubt that anyone thought the very first iteration would be the final form.

No, the guy seems confused as to what happened. The problem wasn’t with leaks that could be detected on the ground. It’s with a vibration environment in space that destroyed the plumbing. The leaks were a side effect. It’s a notoriously difficult problem to solve since there’s only so much you can do on the ground. The engines behave differently, the way the forces are applied is different, the gee loading is different, and so on. That’s not to say they couldn’t have figured these things out, but it wasn’t for a lack of pre-flight testing.