The Official Space and Astronomy Thread v. Well, this is weird.

[XJDenton]

JWST news. May not look like much, but it is experimental confirmation of a galaxy with the largest ever measured redshift, corresponding to a galaxy that existed 400 million years after the big bang.

[Chino]

Everyday Astronaut Tim is going around the moon, that's pretty damn epic!

https://www.youtube.com/watch?v=QFIuzormhYU&ab_channel=EverydayAstronaut

I am so happy for Tim. It's so well deserved. Freaking wild to think that 6 years ago he hadn't even made a video yet, and now he's strapping his ass to rocket and getting to see the moon up close.

[Lonk]

More general science than astronomy, but if true, this is huge

US Scientists Reach Nuclear Fusion Breakthrough

Official announcement scheduled for tomorrow, so we will see. I know every couple of years we see headlines about nuclear fusion, so I hope they really did have a breakthrough and is not just a clickbait title.

Everyday Astronaut Tim is going around the moon, that's pretty damn epic!

https://www.youtube.com/watch?v=QFIuzormhYU&ab_channel=EverydayAstronaut

I am so happy for Tim. It's so well deserved. Freaking wild to think that 6 years ago he hadn't even made a video yet, and now he's strapping his ass to rocket and getting to see the moon up close.

Agree, that is really amazing. Happy for him

[Lonk]

https://www.youtube.com/watch?v=r91Q4dAHnUw

The announcement on Nuclear Fusion

[MrBoom_shack-a-lack]

It's amazing how some things gets kinda left out in media, first I wasn't paying attention to it to later realise what a big thing this could be.

[Lonk]

It's amazing how some things gets kinda left out in media, first I wasn't paying attention to it to later realise what a big thing this could be.

Yeah, there was a brief mentioned for 15 seconds on the news and that was about it. I think in part because we won't see the benefits of it (i.e., is not profitable yet) for some time. Maybe another 15-20 years, maybe even more. But yeah, this could be huge in the decades to come.

[XJDenton]

The NIF news is interesting, but definitely not as a big a deal as the press releases make it out to be. The way ICF defines "scientific breakeven" means they don't take into account the efficiency of the lasers themselves when counting the Q value. They produced about 1.5 times the laser energy focused on target, but the lasers themselves only convert about 1% of the electricity they use into useful laser energy. So its still a few orders of magnitude off being a useful energy source.

[El Barto]

Also:

The NIF news is interesting, but definitely not as a big a deal as the press releases make it out to be. The way ICF defines "scientific breakeven" means they don't take into account the efficiency of the lasers themselves when counting the Q value. They produced about 1.5 times the laser energy focused on target, but the lasers themselves only convert about 1% of the electricity they use into useful laser energy. So its still a few orders of magnitude off being a useful energy source.

What does Q represent in this context? If it's still pressure, pressure of what?

[XJDenton]

Q is generically defined as Power out / Power in. So "break even" is when you get as much power out of the fusion reaction as you did heating the fuel to get it going, which corresponds to Q= 1. It then comes down to how you define "Power out" and "Power in".

Scientific break even only considers the power delivered on target verses the fusion power generated, whereas a more more accurate version would also consider the losses of the heating process and the efficiency of these components, so if you are using a laser that only converts 1% of the electricity it uses to useful laser power (since electricity is what we want at the end) then the Q reduces by a factor of 100 under this more strict definition. More strict still is the "engineering break even" which considers losses and inefficiencies in the power plant.

The xkcd comic is taking the concept of breakeven and applying it to water instead of power, implying the dam is generating more water than it consumes. This is clearly ludicrous, which is the joke.

[Chino]

Problem at the ISS. We might need to send up a rescue capsule.

https://fb.watch/hqWZgqAK1f/

[El Barto]

Q is generically defined as Power out / Power in. So "break even" is when you get as much power out of the fusion reaction as you did heating the fuel to get it going, which corresponds to Q= 1. It then comes down to how you define "Power out" and "Power in".

Scientific break even only considers the power delivered on target verses the fusion power generated, whereas a more more accurate version would also consider the losses of the heating process and the efficiency of these components, so if you are using a laser that only converts 1% of the electricity it uses to useful laser power (since electricity is what we want at the end) then the Q reduces by a factor of 100 under this more strict definition. More strict still is the "engineering break even" which considers losses and inefficiencies in the power plant.

The xkcd comic is taking the concept of breakeven and applying it to water instead of power, implying the dam is generating more water than it consumes. This is clearly ludicrous, which is the joke.

Oh, I got the joke. I'm just used to Q meaning pressure. In the comic pressure could have actually worked. In your explanation not so much. I suppose I shouldn't be surprised it represents different values for different fields.

[XJDenton]

Q is generically defined as Power out / Power in. So "break even" is when you get as much power out of the fusion reaction as you did heating the fuel to get it going, which corresponds to Q= 1. It then comes down to how you define "Power out" and "Power in".

Scientific break even only considers the power delivered on target verses the fusion power generated, whereas a more more accurate version would also consider the losses of the heating process and the efficiency of these components, so if you are using a laser that only converts 1% of the electricity it uses to useful laser power (since electricity is what we want at the end) then the Q reduces by a factor of 100 under this more strict definition. More strict still is the "engineering break even" which considers losses and inefficiencies in the power plant.

The xkcd comic is taking the concept of breakeven and applying it to water instead of power, implying the dam is generating more water than it consumes. This is clearly ludicrous, which is the joke.

Oh, I got the joke. I'm just used to Q meaning pressure. In the comic pressure could have actually worked. In your explanation not so much. I suppose I shouldn't be surprised it represents different values for different fields.

"Sir, we seem to have run out of variables"
"What?"
"Yep. All the letters have been used up."

[Azyiu]

Meanwhile, InSight the Mars lander (or its account manager) might have twitted its final message before it runs out of power.

https://www.theguardian.com/science/2022/dec/20/my-powers-really-low-nasas-insight-mars-rover-signs-off-from-the-red-planet

[XJDenton]

Another in a long line of NASA probes that performed well beyond their initially projected scientific missions. Godspeed, little lander.

[MrBoom_shack-a-lack]

Amazing photo taken from ISS by astronaut Josh Cassada.

[Lonk]

Looks like the test flight is a go for today 

https://www.youtube.com/watch?v=6Vb9hFqF6i0

[faizoff]

Looks like it's cancelled for today.

[Chino]

What a tease.

[Lonk]

T-10,Let's hope I don't jinx it again 

[faizoff]

I learned a new term for rocket go boom today, "Rapid unscheduled disassembly"

[El Barto]

That was cool AF! Hats off to the RSO who let the thing fly out of control for a while without pressing the "kaboom" button. NASA guys would have blown it up as soon as it crossed 90°. 

Were the rocket motors supposed to be asymmetrical? Looks like they were missing a few on one side.

That's one of the things I've never fully understood about rocketry. The US approach has been to build a few big-ass motors. The Rooskie method was to slap a whole bunch of small motors onto their rockets, and SpaceX has clearly taken that approach. It seems to me that the rocket motor is necessarily the most volatile component, so adding more of them would simply increase the odds of one of them failing, perhaps catastrophically. Rocket motors do fail.

I learned a new term for rocket go boom today, "Rapid unscheduled disassembly"

Challenger was the textbook example of the rapid unscheduled disassembly. I don't know if they actually referred to it that way, but the term was definitely in use by that time.

[faizoff]

Snark aside it was very cool to see that massive thing launch and do flips. It had like 33 engines.

@El Barto, it was the first time I heard it today

[Orbert]

I learned a new term for rocket go boom today, "Rapid unscheduled disassembly"

Never heard it before, but it has that air of military or government terminology.  Completely accurate, but possibly the least logical way to describe it by normal humans.

[hefdaddy42]

I learned a new term for rocket go boom today, "Rapid unscheduled disassembly"

I saw that.  Very nice.

[El Barto]

I learned a new term for rocket go boom today, "Rapid unscheduled disassembly"

Never heard it before, but it has that air of military or government terminology.  Completely accurate, but possibly the least logical way to describe it by normal humans.

USAF, I believe. There were references to RUDEs (events) back in the sixties. Wouldn't surprise me if it was the favoured euphemism back during the X project days. Elon popularized the expression a few years ago.

[Chino]

Man... That thing flipped like 3 times at a few thousand miles per hour. That's one strong machine!

[lonestar]

Fun launch, sounds like it was a net success with a spectacular ending. Elon stans will toot it as groundbreaking, haters are predictably hating. Hats off to the real people doing the work for taking a huge step forward.

https://www.youtube.com/watch?v=r91Q4dAHnUw

The announcement on Nuclear Fusion

Totally missed this one, this lab is literally 10 miles from where I live. Unbelievable to think that, between Lawrence Livermore and Berkeley labs, the NASA Ames research base (about 10 miles down H101 from where I work), Stanford, UCSF, and UC Berkeley, and the sum total of Silicon Valley, how much of the key scientific progress being made is made in my backyard.

[Evermind]

Man... That thing flipped like 3 times at a few thousand miles per hour. That's one strong machine!

That was my first thought when I saw it rotating several times. The integrity of the whole thing must be outstanding.

Sucks it didn't go as planned but good to see they got it that far, and also I liked that people were still cheering on stream after the RUD, love the attitude (even if it's only for show which I doubt). Hope they'll nail it next time.

[El Barto]

I suspect letting it do somersaults for a minute or two was highly informative. My hunch is that the RSO is instructed to let people gather as much telemetry before hitting the kaboom button. In this case, how often do you get to talk to your rocket while it flies straight down. By Elon's standards this was very much a success story.

[MrBoom_shack-a-lack]

I love Tim Dodds screaming in excitment during lift-off "I'm gonna be on that thing" and then....

[lonestar]

I saw a report that said the hit the destruct button when it started spiraling

[MrBoom_shack-a-lack]

I know Boca Chica is not a ordinary launch facility but a test site but I was wondering why tanks and things are so close to the launch tower given the damage every launch has on it's surroundings especially with the Starship launch. I mean I guess it's convenient to have things nearby when they're working with it but still...

https://www.youtube.com/watch?v=thA8jlgcJ-8&ab_channel=LabPadre
https://www.youtube.com/watch?v=u6m7HJ6_fNw&ab_channel=LabPadre

[jasc15]

I haven't read any dives into the postmortem analysis yet, but based on nothing but the video of the explosion, it looks like a control system sequence failure.  At one point you can see the grid fins deployed, and the vent plumes from the second stage tanks were at an angle to the vehicles axis, which means the whole stack was already moving a bit sideways.  The commentary mentioned the turn-around maneuver, but its not clear if that was actually occurring when announced, or was just anticipated.  If it was already in the turn around maneuver, it would make no sense to allow that command or grid fin deploy command until stage separation was confirmed.  Also mentioned in the commentary was max Q, but again, not clear to me if it actually got that far, or was just mentioned by commentator.

I was in the car during the launch, and listened on youtube for about 2 minutes until the explosion.  I was on my way to a welding facility, and ended up working with a welder who developed the welds used in the raptor engine nozzles.  Spacex ended up purchasing a few welding machines for themselves (~$4M each) and continued their production in house.

[El Barto]

I haven't read any dives into the postmortem analysis yet, but based on nothing but the video of the explosion, it looks like a control system sequence failure.  At one point you can see the grid fins deployed, and the vent plumes from the second stage tanks were at an angle to the vehicles axis, which means the whole stack was already moving a bit sideways.  The commentary mentioned the turn-around maneuver, but its not clear if that was actually occurring when announced, or was just anticipated.  If it was already in the turn around maneuver, it would make no sense to allow that command or grid fin deploy command until stage separation was confirmed.  Also mentioned in the commentary was max Q, but again, not clear to me if it actually got that far, or was just mentioned by commentator.

I was in the car during the launch, and listened on youtube for about 2 minutes until the explosion.  I was on my way to a welding facility, and ended up working with a welder who developed the welds used in the raptor engine nozzles.  Spacex ended up purchasing a few welding machines for themselves (~$4M each) and continued their production in house.

Scott Manley dug into it a bit. There were 5 Raptors out and another was squirrelly. Three were out by the time it lifted off, and it looked like there as a hydraulic failure around the same time, and the CW is that so much debris was kicked up by the thing that the first stage suffered significant damage as a result. Stage 0 (what SpaceX calls the launch pad) will be the focus going forward. Elon was opposed to using a flame diverter (there won't be one on the Moon or Mars), but it looks like he's probably going to have to. As for it losing control, two of the failed Raptors were gimblers, and if there was a hydraulic failure other ones might not have been able to gimble, so it probably just went outside the motors' ability to keep it stable.

[jasc15]

I noticed some raptors out, and later learned about the pad damage, but didn't connect the two.  That could explain hydraulic failure, or at least reduced attitude control resulting from lost gimbal engines.  But then why were the grid fins deployed?  Seems like a strange hydraulic failure mode.