When Isaacson asked Musk later that day whether he thought he’d been too harsh with Hughes, Musk replied, “I give people hardcore feedback, mostly accurate, and I try not to do it in a way that’s ad hominem … Physics does not care about hurt feelings. It cares about whether you got the rocket right.”

Physics does not care about hurt feelings, and it also does not care about DEI standards. Musk’s hiring policy is as simple as it is effective: “I believe in a strict meritocracy. Whoever is doing great work, they get more responsibility. And that’s that.”

He worries that unchecked, “the woke-mind virus, which is fundamentally antiscience, antimerit, and antihuman in general,” could lead to civilizational decay and AI domination of the human race. In his words, which apply to the regulators and the critics, “Every year there are more referees and fewer doers.”

Musk is not perfect, and there are plenty of decisions to criticize, whether his bizarre family life, his Starlink refusal, or his sophomoric tokes and jokes. But perhaps, as Elon deadpanned on “Saturday Night Live,” it might be too much to expect that a man single-handedly transforming society would also be a “chill, normal dude.” If we end up on Mars, we’ll know who to thank.

abie Ars Scholae Palatinae
5y
764

malor said:
The SLS is just so dumb. It uses the most complex and expensive engines ever built, which justified their cost by being re-usable, straps four of them to a stick, and then throws them in the ocean.

What a pile of crap that design is.

Another contender for 'dumbest design' is ISRO's PSLV. This is a 4 stage rocket that has:
1) The first stage is a a large solid rocket booster
2) Up to six additional strap on (giggity) SRBs, albeit optional - ISRO considers these part of the first stage
2) The second stage is powered by a single 'Vikas' engine that uses hypergolic propellants (UDMH/N2O2)
3) The third stage is another SRB
4) The fourth stage is powered by two engines that use different hypergolic propellants from the second stage(MOH/MMN)

https://arstechnica.com/civis/attachments/pslv_c51_b-jpg.58966/

All very Kerbal. This Rube-Goldberg machine manages to send up to 3800 Kg to LEO, or about 17% the payload of a Falcon 9 without reuse. I get that the rocket is an evolution of previous designs, but why didn't someone at some point not take a step back and ask if maybe a clean sheet approach would be better? 5 separation events, 3 different SRB designs and two completely different liquid stages, sheesh.

The late-night liftoff of a Falcon 9 rocket with another batch of Starlink Internet satellites on Sunday set a new record for the most flights by a SpaceX launch vehicle, with a first-stage booster flying for a 16th time. SpaceX now aims to fly its reusable Falcon 9 boosters as many as 20 times, double the company’s original goal.

The flight followed several months of inspections and refurbishment of SpaceX’s most-flown rocket, a process that included a “recertification” of the booster to prove, at least on paper, that it could fly as many as five more times after completing its 15th launch and landing last December. //

It was SpaceX’s 216th successful mission in a row for the Falcon rocket family, a record unmatched in the history of space launch vehicles.

The booster flown Sunday night, numbered B1058 in SpaceX’s inventory, debuted with the company’s first launch of astronauts in May 2020, sending NASA crew members Doug Hurley and Bob Behnken toward space on the Crew Dragon Demo-2 mission. That mission ended a nearly nine-year gap in US launches carrying astronauts into orbit.

SpaceX’s fleet-leading booster has now launched 801 spacecraft and payloads, plus two astronauts, in more than three years of service. //

SpaceX’s latest iteration of the Falcon 9 rocket design—called the Block 5—flew for the first time in 2018. At that time, SpaceX had the goal of launching each Falcon 9 Block 5 booster 10 times. With boosters still coming back in good shape after each flight, SpaceX extended the life to 15 launches and landings, according to a report last year by the trade magazine Aviation Week & Space Technology.

The magazine reported that SpaceX put booster components through vibration testing to four times the fatigue life of what they would experience over 15 flights, giving engineers confidence that the rockets will continue to fly successfully. //

SpaceX started the year with the goal of flying 100 missions in 2023, the most flights in a year by any launch provider. SpaceX flew 61 times in 2022. The Falcon 9 continues to be the workhorse for the launch industry as SpaceX tests its much larger Starship vehicle, which engineers designed to eventually be fully reusable with an even faster launch cadence.

But the main limitation of SpaceX’s blistering launch rate is not the availability of flight-ready rockets—it’s the turnaround of the company’s three Falcon 9 launch pads. SpaceX has flown out of Space Launch Complex 40 at Cape Canaveral Space Force Station as often as once every five days. The Falcon 9 launch pad at Vandenberg Space Force Base in California can be set up for another mission in fewer than 10 days.

On May 26, SpaceX shared an inspiring 2-minute video of its first-ever fully-integrated Starship test flight featuring spectacular views of Earth from Starship's onboard cameras, scenes from Mission Control, and spectators' excitement upon seeing the massive stainless-steel vehicle liftoff from the Starbase launch site last month, see video clip below.

Steve Baker
Senior Software Engineer (2013–present)Apr 24

Will SpaceX upgrade Starship to more than three vacuum Raptor engines?

The problem is with the space available.

Although you can fit 33 sea-level Raptors into the 9 meter diameter space at the tail end of the SuperHeavy - the vacuum optimized Raptors need a HUGE engine bell.

Just look at the difference in size (sea-level raptor on the left - vacuum-optimized on the right)…the two engines are almost identical aside from that!

It’s interesting to look at the 1st and 2nd stages of the Falcon-9. It has nine sea-level Merlin engines packed underneath the main rocket - but the second stage has the same diameter - and it’s is pretty much FULL with just one vacuum optimized Merlin!

Same exact rocket motor - but giant bell required for vacuum work.

Wikipedia's information is a little ambiguous:

The booster's tanks were reported as holding 3,600 t (7,900,000 lb) of propellant, consisting of 2,800 t (6,200,000 lb) of liquid oxygen and 800 t (1,800,000 lb) of liquid methane. However, current booster prototypes can only hold 3,400 t (7,500,000 lb) of propellant.

Depending on how current "current" was when that was written, the booster carries no more than around 800 tons of methane fully loaded; 14% would be 112 tons. Add another 30% or so for Starship and we're up to 145 tons.

The total amount of methane in the atmosphere is about 5,000,000,000 tons, so this is an increase of about 0.0000029%.

Note that the FTS is designed to get combustion started, so most of the remaining methane was actually burned. Even if none of the methane burned, the destruction of another 344,000 Super Heavy boosters late in ascent would increase atmospheric methane by 1%. //

for comparison May 22, 2023 Pipeline Technology Journal: Two Fields In Turkmenistan Leak More Greenhouse Gases Than The UK: Leaks Could Be Easily Fixed estimates 2.6+1.8=4.4 million tons per year (2022) for just these two newly-discovered leaks. So the max here is 0.0002 "newly-discovered annual Turkmenistan leak units". It is true that burning it and converting it to CO2+H2O might be greener, but... –
uhoh
11 hours ago

Elon Musk @elonmusk
·
Replying to @krassenstein
You assume they are good intentions. They are not. He wants to erode the very fabric of civilization. Soros hates humanity.
10:14 PM · May 15, 2023 //

Elon Musk may not be a conservative. He has his issues, like all of us. But he’s a considered thinker, who seems to be learning fast about the dangers of the left. He’s spoken about the threat to civilization in the past posed by the “woke mind virus.”

Musk showed again that he does have some understanding of the left during an interview he gave to CNBC on Tuesday. //

Musk was asked about why he made his comment about Soros during the interview and he laughed at the interviewer, David Faber. “I think that’s true, that’s my opinion,” Musk responded. //

But why share it if people might not agree with you? Faber asked. What if advertisers on Twitter or Tesla buyers might not agree?

Boy, isn’t that a liberal in a nutshell? Why not share it if it’s his opinion? Is he supposed to go easy on what he thinks about Soros because it will upset the left? Maybe it’s more important to point out that Soros is doing harm to society. The look on Musk’s face in response was priceless — like, are you nuts?

He paraphrases Inigo Montoya in “The Princess Bride”: “Offer me power, offer me money, I don’t care.” To drive the point home, Musk declared: “I’ll say what I want to say, and if the consequence of that is losing money, so be it.”

What exactly is a full-flow closed cycle staged rocket engine like the SpaceX Raptor?

Well, this gets a bit complex, since to understand what the sentence means you have to understand how a rocket engine works. I’m going to try to go from the basics up…

I mean, it’s not like it’s rocket science, right? //

In case you’re wondering, it’s only the third one ever built — really, only the second full engine since the “full-flow power-head demonstrator” never actually had a combustion chamber attached. The other is the Russian RD-270 engine.

It’s also the first full-flow, closed-cycle, dual-shaft, staged-combustion rocket to ever fly. So far, it’s only 20 meters or so, but it did fly. (Update: 12.5 kilometres now…)

So there’s your answer.

"SpaceX has moved very quickly on development," Kirasich said about Raptor. "We've seen them manufacture what was called Raptor 1.0. They have since upgraded to Raptor 2.0 that first of all increases performance and thrust and secondly reduces the amount of parts, reducing the amount of time to manufacture and test. They build these things very fast. Their goal was seven engines a week, and they hit that about a quarter ago. So they are now building seven engines a week."

To put this into perspective, the Raptor 2 rocket engine produces approximately 510,000 pounds of thrust. This is almost identical to the amount of thrust produced by the RS-25 engine that will be used to power NASA's Space Launch System rocket. This engine was designed and developed by Rocketdyne in the 1970s for the space shuttle program, and the company has decades of experience manufacturing them. //

In 2015, NASA gave Aerojet Rocketdyne a contract worth $1.16 billion to "restart the production line" for the RS-25 engine. Again, that was money just to reestablish manufacturing facilities, not actually build the engines. NASA is paying more than $100 million for each of those. With this startup funding, the goal was for Aerojet Rocketdyne to produce four of these engines per year.

Kirasich said that as it builds and tests Raptors, SpaceX is rapidly iterating on these processes and producing higher-quality engines.

Elon Musk

·
May 13
@elonmusk
·
Follow
Replying to @elonmusk @NASASpaceflight and @SpaceX
Raptor chamber wall might have the highest heat flux of anything ever made
Chris Bergin - NSF
@NASASpaceflight
·
Follow
Can Raptor 3 can be a drop-in replacement for Raptor 2, or will the vehicles require changes to cater for Raptor 3 engines?

Here's the full firing from the raw pull out of http://nsf.live/mcgregor
1:14 / 1:14
7:29 AM · May 13, 2023 //

Also, Super Heavy is getting very very close to a SRB in terms of thrust density (~1388 vs ~1367kN/m²). Fascinating.

With ~30% higher ISP… meaning ~69% higher power density.

There really is no one close to SX now at making rocket engines. //

I don't want to knock down the SpX engineers working on this thing, if anything, it reminds me of the SSME development. That engine program had its fair share of failures, but, in the end they produced (in my humble opinion) the finest and most reliable rocket engine ever developed (and LH2 powered at that, no small feat), a true pinnacle of U.S. aerospace engineering. Hopefully SpX can rise to that level, because their architecture really needs it. //

Merlin has now exceeded RS-25 in reliability in terms of consecutive successful engines on orbital launch (by about half an order of magnitude). RS-25 had an engine-out on STS-51F on the 19th Shuttle launch, and SpaceX has had more Falcon launches since then without any engines out than the rest of the Shuttle program combined plus had at least 3 times as many engines. (Rs-25 had other hiccups, but I think that’s the only full engine-out? Can’t remember.)

A lot of that Merlin reliability is just the sheer number of engines and number of launches, making more of a difference than any particular feature of the engine, allowing tweaking to improve engine reliability and large manufacturing and test volume that allows quickly achieving really good engine statistics. RS-25 had both clustering and a fairly decent flightrate in its favor, but not as much as Merlin.

V2 has less visible plumbing and wiring, both sea-level versions have the same nozzle exit diameter and similar dimensions, however, V1 has a mass of 2,000 kilograms (kg) and V2 1,600 kg. Raptor V1 generated around 185 tons of thrust and the current V2 generates around 230 tons of thrust. //

This week, the third version of the Raptor engine (V3) reached a new thrust record. “Raptor V3 just achieved 350 bar chamber pressure (269 tons of thrust). Congrats to SpaceX propulsion team!” announced SpaceX founder Elon Musk via Twitter. “Starship Super Heavy Booster has 33 Raptors, so total thrust of 8877 tons or 19.5 million pounds,” he said on May 13. //

As of November 2022, SpaceX completed manufacturing over 200 Raptor engines (and counting) at an average rate of one engine per day. The company manufactures and tests the engines at the McGregor factory. SpaceX officials recently said that they has more engines than they could fly at the moment. SpaceX aims for the cost-per-tonne of thrust of each Raptor to be under $1,000 USD, so a bit over $250,000 at the 260 tons of thrust that each Raptor V3 is capable of generating. Musk said recently that he expects to spend approximately $2 Billion on Starship's development this year

Photos

On Sunday 1/15/23 at 5:56 pm local time, a SpaceX Falcon Heavy launched a mission for the Space Force, USSF-67. I was able to track one of the boosters from launch at LC-39A to landing at LZ-1. This was filmed with an 11" Celestron NexStar GPS using a Blackmagic Pocket Cinema 4K camera at an effective equivalent focal length of 5.6 meters.

This used a new, experimental version of my RocketTraker software, adaptively looking through the trajectory prediction published by FlightClub.io and seeking the closest point in the trajectory file based on the rocket's observed position and time. This allowed for greater tolerance of deviations from the expected timing of the booster landing and allowed me to follow it all the way down. This new version of RocketTraker will be published soon on my community page exclusively for channel members!

On Sunday 1/15/23 at 5:56 pm local time, a SpaceX Falcon Heavy launched a mission for the Space Force, USSF-67. I was able to track one of the boosters from launch at LC-39A to landing at LZ-1. This was filmed with an 11" Celestron NexStar GPS using a Blackmagic Pocket Cinema 4K camera at an effective equivalent focal length of 5.6 meters.

This used a new, experimental version of my RocketTraker software, adaptively looking through the trajectory prediction published by FlightClub.io and seeking the closest point in the trajectory file based on the rocket's observed position and time. This allowed for greater tolerance of deviations from the expected timing of the booster landing and allowed me to follow it all the way down. This new version of RocketTraker will be published soon on my community page exclusively for channel members!

Thanks to Reds Rhetoric for the static camera footage, be sure to check out his channel and footage of this launch:
  

 / @redsrhetoric  

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