Business, Space, Technology and Society

Another Delay

107 Comments

Might be weather. That pushes it to at least Friday.

[Wednesday-evening update]

Yes, as noted in comments, apparently the launch is back on for tomorrow morning. Elon must have really wanted to do it on 4/20.

[Bumped]

[Late-evening update]

[Thursday-morning update]

Well, the excitement happened. It will be interesting to see the post mortem, but just getting off the pad and through max-Q were major milestones for the first flight of such a beast.

[Afternoon update]

Here‘s Eric Berger’s take.

And more thoughts from Blake Powers.

Marina Koren’s story on Elon’s explosive day.

107 thoughts on “Another Delay”

  1. The Weather Channel says:

    Day:

    Considerable clouds early. Some decrease in clouds later in the day. High near 80F. Winds SE at 15 to 25 mph.

  3. Here’s the NOTAM.

    Issue Date : April 18, 2023 at 2211 UTC
    Location : Brownsville, Texas
    Beginning Date and Time : April 20, 2023 at 1328 UTC
    Ending Date and Time : April 20, 2023 at 1505 UTC
    Reason for NOTAM : Space Operations Area

  4. One of the many problems with Twitter as a news medium, the lack of context or follow-up. The TFR for 4/20 was withdrawn, and almost immediately re-issued with slightly different start/end times.

  5. Elon must have really wanted to do it on 4/20.

    Well, he is an advocate of weed deregulation and “420” (including symbolic times such as April 20 and 4:20 pm) is a 50 year old term that has been used for marijuana usage and advocacy for legalization (originally a code phrase coined by some highschoolers, one or two who later became roadies for the Grateful Dead and spread the use of the term far and wide).

    We’ll see if it happens then.

  7. How much digital ink will be spilled today and tomorrow about how only the government should be involved in spaceflight and “how glad we are that nobody was on board when the rocket exploded”?

    Data, data, data.

    The fact that it even cleared the tower (it appeared to be ‘sliding’ a bit on takeoff) is amazing.

    I loved the views of the engines glowing and the feed chyron showing the engine count/flameouts

    Can’t wait for the next one!

  8. Looked like maybe 4-5 engines out on Super-Heavy … amazing that it still remained on-track past Max-Q and almost to MECO. Next attempt should also be exciting. Looking forward to Elon’s post-game wrap-up.

    1. Hey, I’m Eric W and I didn’t write that …

      Regardless, what an adventure! Hope they can salvage the cryo tanks, looking a bit dicey right now.

  9. Well it took off – seemed to take forever to start moving.

    I could see 3-5 first stage engines not working.

    And there seemed to be bursts of yellow in the exhaust from time to time.

    Then apparently it has to do a flipping maneuver for stage sep but it kept wobbling around long after the stages should have separated.

    Then it blew up.

    Don’t know if it self-destructed or if the range safety officer issued a destruct command but I’m sure we’ll find out soon.

    So a partial success.

    1. Flight termination for most rockets launched from US ranges is autonomous now. No range safety officer in the loop. There’s an independent computer on board that reckons the vehicle’s position and fires the charge if it goes outside a pre-programmed corridor.

  10. Of all the faults that could pop up on this flight I was not expecting stage separation failure. Also more than 1-2 engine flame outs (I counted 5-6) is worrying but I am sure they will figure it out.

    1. Stage separation was an issue for Falcon-1 attempt #3 when the two collided shortly after separation causing flight failure. IIRC, Elon mentioned that a successful stage separation event would be a major hurdle for Starship/SuperHeavy.

      It’ll be interesting to hear what the issue was.

      Also there appeared to my untrained eyes to be some fiery events around the base of the SuperHeavy on its way up besides engine shutdowns and some green flames, often indications of “engine-rich” combustion.

      Looking forward to the day when those pretty blue rings stay lit up until BECO.

  11. Fantastic launch. It is always great to hear and see the enthusiasm of SpaceX employees during the countdown and launch. That’s the passion that will drive others to want to follow their path.

    Like others, I noted the slow liftoff, which I wondered was because about 3 engines seemed to be out even prior to liftoff. That those engines were out and they cleared the tower and surpassed MaxQ was amazing.

    I don’t understand the flip for separation. What I though I had seen as a flight profile was separation followed by a super heavy flip. I don’t know what you would gain by flipping then separating. Whatever the case, I now wonder if they simulated so many engines being out (by this point at least 5 now out and 3 within about 45 degree arc of the thrust) and conducting the flip. With that much asymmetry at that high of altitude (less aerodynamics) it would be hard to regain stability.

    I’ll venture to guess that they probably allowed too many flips. It seemed pretty clear by the start of the second flip they had lost the flight profile. I think it was great to continue the test, as the area was clear and everything looked safe. However, I fear others will worry that somehow the spinning stack might have gained stability in a different direction, which is usually why self-destruct is initiated. I think allowing it to continue to spin offered a chance to get some awesome stress load data, which could potentially allow for better flight control and stability at those high altitudes. So, I’m glad they let it go a bit longer.

    Great job SpaceX.

  12. First thing that comes to mind is that they are going to have to re-think the launcher. Flying concrete everywhere is not optimal.

    Second thing is the Raptors – six were failed in the video at 1:17.

    Hope they can try it again this year!

    2. Some of the pieces I saw flying/falling in a slow mo replay looked more like the cladding from the Orbital Launch Mount falling than concrete, though I’m sure there was plenty of concrete launched around, too.

      The cladding on the tower looks like it took a beating, too. I can only imagine how much more it would suffer during a landing burn.

      1. Actually, the landing burn will be far, FAR less damaging. Only 3 engines vs 33 (and presumably at low throttle), and much further above the ground at shutdown.

  13. The RUD was via AFTS, suggesting a pretty tough stack! Stage separation is always fraught (as we’ve often seen with new rockets, including Falcon 1 and several recent examples). Saturn 5 used retrorockets on S1C and prograde ullage rockets on S2, which made quite a display in the sky. The Starship stage separation uses centrifugal force to push the stages apart after latch disconnect. I think I said earlier I was worried about those latches (but I don’t know if that was what failed). It also looked like there was some kind of SH engine bay fire, making me wonder if one or more Raptors continued to fire (which would make stage separation fail). We’ll find out, I guess. I counted 6-7 first stage flameouts during ascent, including one landing engine in the center 3 and 5-6 on the outer thrust ring, most on one side. Not the worst first attempt for the largest rocket ever. There was a B57 watching.

    1. SpaceX, like SPECTRE, should have built Starbase inside a defunct volcano in the middle of the Pacific and so remote the press wouldn’t bother to cover it.

      1. Elon mentioned building a volcano lair a couple of times, but then he bought Twitter.

        Personally, I think the volcano lair would have been a sounder choice. 🙂

    2. Yeah, the NYT is calling it a failure and setback “for NASA’s moon plans”. I guess they got that from someone at NASA, because I don’t see the setback for SpaceX.

    1. I should say Stage 0 more or less intact. I haven’t see any damage assessments yet of actual damage to the pad itself. There was a lot of debris falling out of that cloud so we’ll see.

      Love that they kept going at high altitude as long as possible to collect tons of data during the rocket firing. This will be very helpful.

      Seeing the video from NSF they, like the Walter Cronkite experience on the first launch of the Saturn V, have some camera stability issues to work.

      1. I’ve heard some claims of 20 foot deep crater under the pad. I’d like to see where they’re getting the data. There’s definitely big chunks of concrete several hundred yards away, saw that for myself on Lab Padres’s cameras.

          1. That’s some pretty significant excavation. Am I out to lunch to suggest they dig a little deeper and fill it with water? Steam yes, chunks of concrete? No.

            I’m reminded of a movie title: “A River Runs Through It”. Yes a horrible movie as well. 10 o’clock, 2 o’clock, 10 o’clock, 2 o’clock…. 🙂

            Or they could raise the next OLM by 18 feet. lol…
            Is this an r squared problem?

          3. The craziest solution would be to make the bottom of the pad out of 33 upwards facing Raptor engines, since they can withstand Raptor engine firing. If all 66 were lit at once even more excitement would be guaranteed.

          5. @elonmusk you DEFINITELY need a flame diverter and a deep deeeeep trench. 10:58 AM · Apr 20, 2023

            @not_elonmusk OTOH, have we got a great new tool for The Boring Company!!!

          6. ttps://www.businessinsider.com/spacex-starship-rocket-crater-concrete-launchpad-upon-liftoff-2023-4

            Hmm, might need more copper pipes.

  16. Now I have textbook-grade video to explain the concept of : ‘ass over teakettle’ to the uninitiated too!

  17. National Geographic reported the flight as a very positive milestone in the development of human space exploration. From what my wife tells me, Fox News was derisive in its coverage. Those are the opposite of what I would have expected.

    Kat and I are both basically rochet propulsion engineers, and have both studied the Raptor for professional reasons. It is the most advanced rocket engine ever built, and not just by a small amount. To have 33 of them running at the same time is a monumental achievement. That most of them worked all the way through the SuperHeavy burn time is a feat of engineering we don’t see enough of these days. (I really liked the SpaceX graphic in their broadcast showing engines out in rea time.)

    And, yes, as noted above, staging is always a problem. I spent years dealing with it in ICBM development, in the relatively simple world of solid propellant rockets.

    Elon himself gave this flight only a 50-50 chance of getting to the Starship target point. He and his team succeeded in the hardest part of the flight, and anyone who calls this flight a major failure doesn’t understand the process.

    SpaceX is to be congratulated, enthusiastically.

    1. Serious question from a non-propulsion engineer, but what is the reason we were able to see all of the individual bells glowing on the tracking shots compared to the mostly obscured view of the tail of Falcon 9 as it launches?

      Propellant choice? Fully staged combustion? Camera tricks?

      Genuinely curious.

      1. Good guess! Merlin engines use kerosene fuel, which produces more unburned long-chain hydrocarbons in the exhaust (“soot”). These molecules are the right size to radiate and absorb visible light, so to our eyes they glow really bright when they are hot enough of them makes the plume opaque.

        Raptor uses methane fuel, whose exhaust has relatively low emissivity in the visible spectrum, so the light our eyes sees passes through the plume relatively unaltered.

        1. Also Merlin is a gas generator cycle engine which means a few % of each engine’s exhaust is relatively rich with unburned fuel. Raptor on the other hand is full-flow staged combustion, which burns the fuel more efficiently (more CO2 and H20 in the exhaust, which are both poor visible light absorbers).

    3. First SpaceX blew up a rocket. Then Musk blew up Twitter’s verification system….

      And so is its founder, multitasking between overseeing rocket launches and turning Twitter into a bug-ridden catalog of far-right rhetoric.

      That’s a feature, not a bug…. lol.

      OK, we get *her* perspective. OTOH maybe she should host an interview with Shotwell and get her narrative better aligned….

      1. The Progressive Marxists look really silly with the irrational complaints about Twitter but I can understand how people who paid $10,000 or more to get their blue check are offended that it only costs $8 now.

        They also look silly with similar complaints about SpaceX.

  20. My take on the launch; I think the pad damage is a lot more significant than we yet know, due to causing most of the problems seen on the flight.

    Here’s my scenario (pure uninformed speculation) of what occurred;
    A few of the high speed pieces of the concrete slab (which is now a deep crater) impacted on the booster (the exhaust plume would not prevent this). This caused at least some of the raptor failures (including at least some of the ones that explosively failed during climbout), but also damaged the hydraulic lines and, perhaps, the APUs driving the hydraulics. This led to a loss of hydraulics about a minute into the flight, resulting in no more engine gimbaling, and leading to a pre-MECO tumble of the stack.

    I’m biased on this, as I’ve long been a critic of the orbital launch mount design. Especially the flame deflector, which is just a flat slab of concrete (and this isn’t the first time that flying concrete has damaged a Starship). A water deluge won’t help; the issue is force and pressure, which will easily blow away any water layer.

    What’s needed? IMHO, a real flame deflector, an angled one (there’s ample room under the launch table, which is well off the ground). I’d favor thick steel (two or more inches). Salvaged armor plating (such as from old warships) would do nicely. Or, go with a flame trench (also steel-lined).

    1. I would have a wall [or floor] pipes, but pipes at different height, so that gas can go thru them, but a bullet can’t.

      1. Copper pipes with water flowing in them.
        {Which are designed so they can’t be over pressurized by the water becoming steam.}

      2. George, I was corrected on a prior thread on that (my sincere thanks to the person who corrected me – sorry, can’t find that thread so can’t find your name to thank you properly) and I listed it as a spin too. What it actually is is a partial spin, going through about 90 degrees before sep.

        In this case, IMHO we saw a loss of control, not the planned “spin”. The altitude for sep was way off (supposedly Starhip stages at around 80km, while this flight never got above 39), plus the 1st stage was still thrusting (plume shockwaves are visible.) Might just be residuals venting, but that’s enough to impart thrust and prevent separation. (As I recall, one of the Falcon 1’s had the booster recontact the upper stage due to residual thrust).

        My guess; I think they’ll try this separation method again. Doesn’t mean it’ll work, but I don’t think they’ll abandon it just yet, especially not if the primary cause is determined to be something unrelated to the sep method.

    2. Eighteen inches of armor from the Iowa battleships!

      Oh darn it all went to Japan to make razor blades.

      1. It just so happens that the Port of Brownsville has a Breakers Yard which takes apart old warships. It wouldn’t be a long drive to get such goodies!

    3. What’s needed? IMHO, a real flame deflector, an angled one (there’s ample room under the launch table, which is well off the ground). I’d favor thick steel (two or more inches). Salvaged armor plating (such as from old warships) would do nicely. Or, go with a flame trench (also steel-lined).

      In a tweet I cited above, Elon appears to agree with you about a flame deflector AND a deeper trench. Exact geometry TBD, it would seem.

      1. Lol, Elon Musk has changed his tune from 18 or so months ago, when he said something like; We’re going to try this without a flame deflector, though we may regret it. I don’t have the exact quote, but that’s very much the gist of it.

        The day I saw that was the day I decided that they were making a huge, huge mistake regarding the stage 0 design, because with no flame deflector, they’d get massive damage, which would probably include the 1st stage.

        So, now, thankfully, he wants both a deflector and a flame trench. I just hope they make the trench sufficiently massive that it won’t float during wet weather (I’ve seen more than one empty swimming pool rise up a few feet due to this).

  21. I could be completely wrong about all this, but I seem to recollect that spinning the entire rocket is a low-cost method of stage separation that comes from what they’ve been doing to fling Starlink satellites. It doesn’t take any extra hardware (thrusters) to separate the stages if you use the existing TVC system to set the entire vehicle spinning so that centrifugal force will separate them.

    If that is the case, then if for some technical reason (I’m guessing software) the stages fail to separate, what is plan B? What I could imagine as a scenario for today was that the programming was too sequential, and the stage-separation routine was waiting for a set of conditions that was too narrowly constrained (such as limits on altitude, dynamic pressure, or a very particular rotation velocity), and thus the separation sequence never initiated.

    Since the booster isn’t supposed to despin until the stages separate, and in any event it might not have sufficient RCS thrust to despin with the huge mass of a fully fueled Starship still attached, it may have never even tried. It certainly wouldn’t relight the main engines to despin because there’s no point in despinning until the Starship separates, and the Starship can only separate if the stages are spinning. Tumbling to destruction is the only logical outcome. It would definitely be a major failure mode.

    And what we saw today illustrates why it’s not an acceptable separation method in an operational system. The Starship was at or near the target velocity and in theory should have had a range of abort options. Step 1 would be to get clear of a dead booster, but obviously if it depends on the booster entering a proper rotation, and the booster can’t properly rotate, a booster malfunction guarantees the loss of orbital vehicle.

    So I expect that they’ll not stick with this separation method.

    1. The booster started tumbling around T+2:20. Stage sep was not planned until around T+2:40, if I recall correctly. The tumble had nothing to do with the planned flip and separate, IMHO.

      You can see what appears to be a hydraulic power unit failing dramatically (pieces falling and fire) at around T+0:30, so it seems hydraulic power to drive the gimbals was compromised. If the staging system is also hydraulic, this would explain why no separation occurred, as well as why the vehicle lost control.
      There are at least 2 hydraulic power units as I recall, but if the system had been sufficiently damaged that fluid and pressure was being lost (likely), then a control failure at that point would be expected.
      Note that the next booster has electric TVC.

      Sep time came with the vehicle low and slow (<40km, 2,000km/hr). For comparison, a typical Falcon9 RTLS mission may stage at around 60km and over 6,000km/hr!
      There may have been far more Q on the vehicle than planned, as well as rotational forces, which may have contributed to stages being unable to separate.

      For a nominal stage sep event, there is no need to use RCS to 'de-spin' stage1, as the maneuver doubles as the flip to boost-back orientation, so this can be handled by the main engines.

      1. You can see what appears to be a hydraulic power unit failing dramatically (pieces falling and fire) at around T+0:30, so it seems hydraulic power to drive the gimbals was compromised.
        I noticed that too, but hadn’t associated it with the hydraulic power, but that makes perfect sense and would explain a lot of what we saw subsequently. If it was losing fluid you’d see a gradual loss of control until finally, unable to gimbal engines properly it would start to tumble. Fortunately it was high enough and out of dense air so that it remained structurally intact largely throughout.

        Still to be seen if it was damaged because of concrete kick-up from the pad at launch. There was a lot of crap going the wrong direction at launch.

        Such a problem to have! I’ll take it any day….

        Dave’s First Rule Of Rocketry…

  23. A few mini-points:

    The reason kerolox rockets have so much flamey goodness is because burning kerosene makes a lot of soot. The flamey appearance in the lower atmosphere is because the exhaust contains incandescent soot burning in the atmopsheric oxygen. Higher up, where’s not much air, you see kerolox rocket exhaust looking blackish. CH4, not so much soot; H2, no soot. Delta IV exhaust is flameyish because it’s got an ablative engine liner, so deliberate engine rich exhaust.

    By my count, there were at least 9 engines out, just not all at the same time, because one outer ring engine had a flameout, then spontaneously re-lit. Which means whatever made the flame blow out, the turbine kept on running, pumping superheated CH4 and O2 from the pre-burner into the chamber, where it re-lit (which is how the chamber lights in the first place; only the preburners have spark plugs now).

    The HPU explosions/failures are controversial, some some SpaceX little birdies are saying otherwise. Some things went bangular during ascent, but could have been engines. In any event, never to be seen again, as B9 and bosters futureward are have electromechanical steering.

    My sense is, SpaceX elected to discard obsolete OLM and stack by throwing them away in the sky.

    I don’t *think* there can be an exhaust trench without building an artificial hill a la Apollo, so only a water-cooled diverter? Time will tell, and I’ve been wrong before. Wheel Sea!

    1. Okay, here’s another off-the-wall idea.

      What if one side of the launch platform had a bunch of horizontal Raptor engines whose exhaust impinged on the downward exhaust stream of the rocket, such that the resulting exhaust angle became 45 degrees instead of vertical?

      Then the horizontal surface below the platform would in effect already be angled at 45 degrees relative to the exhaust stream.

  24. “My sense is, SpaceX elected to discard obsolete OLM and stack by throwing them away in the sky.”

    Yes. Saves cost of dismantling, boosts employee morale (we need to LAUNCH something), gives the teams launch practice and gathers heaps of useful data. Wins all round.

  25. Is SpaceX going to get the parts rocket out of the ocean?
    Or is other ways to determine that engine failures were due flying concrete?

    1. The engines were obsolete, and B7’s backup B8 will be scrapped, engines and all. It doesn’t matter why the engines failed, and they know they need to avoid throwing concrete for a thousand meters in all directions.

    2. There were many cameras and much telemetry. I’m confident they already know the answers to these questions.

      There is a LOT of raptor-2 testing going on on a daily basis, so they probably have a good understanding of their reliability. However, it is a very complex, difficult engine.
      Also noteworthy in some telephoto video of the launch, is that many running engines were running dimmer than others, suggesting lower thrust that intended.

  26. Buried under all the sturm und drang, John Carmack was a guest in mission control in Texas. He’s the logical choice to take over as Twitter CEO.

    3. The Starship is powered with methane, which is in turn purified from natural gas.

      Natural gas, we cannot have any of that! The rocket needs to be powered by electricity. Storage batteries. Lots and lots of storage batteries.

      1. …And solar cells, don’t forget the solar cells! Makes night launches preferable. Oh wait! Come to think of it, there’s a tremendous amount of wind power available on ascent, just use that! *

        *There is a sad aside commentary to this that notes that many degree’d graduates from accredited colleges might agree with this…

        For those people, I think this would be a great essay exam answer for those we wish to send overseas to serve in the foreign service as diplomats to dictatorships.

  28. Does anyone know why the booster grid fins were deployed on ascent. Seems like an unusual choice — why add drag during ascent? Do the 13 gimbaled engines not have enough control authority by themselves?

    1. They are fixed and are not retractable. This was done on purpose to eliminate the mass and complexity of having them rotate outwards and lock into position like they do on Falcon 9. They are also a lot smaller than was in the original design. Turns out the size isn’t needed, only enough to stabilize the rocket in the proper orientation during entry. As you surmised, the engines can gimbal for fine control and do. Originally hydraulically but in the next version electrically (see above). The rocket upon return does not land but is intended to be captured by the two arms at the top of the launch tower known as “The Chopsticks” and then eventually the rocket is rotated and lowered back onto the Orbital Launch Mount (OLM), the ringed leg structure you see the rocket resting on prior to launch. and often referred to as part of “Stage 0”, the ground-based infrastructure. The additional drag is insignificant compared to the thrust of the SuperHeavy and as Elon likes to say, “The best part is no part”.

      1. Thanks for the explanation!

        I knew about the plans to “catch” the booster using the “Chopsticks,” but I hadn’t heard that the fins were fixed. Given how rapidly the Raptors can gimbal, based on what we saw during Starship flight testing, it makes sense that movable grid fins aren’t really needed for control. And I certainly agree with their “the best part is no part” philosophy — every time I hear about new features on appliances/cars/etc, one of my first thoughts is “yeah, but what about when that new part fails?”

        1. The last I checked the fins are still movable (tiltable) along the x-axis (an imaginary line at 90 degrees to the long axis of the rocket) to help steer the rocket through the atmosphere much like the Falcon 9. Last I heard they were made of stainless steel rather than Falcon 9’s titanium. Things change so quickly on Starship/SuperHeavy information from 2021 can easily be out of date. In this case I don’t think so, but if I’m wrong I’m sure someone else here can correct me.

    2. He is right that it is Musk’s responsibility if not fault. The mitigation measures the author raised have been talked about and it is certain that the SpaceX team has had those discussions too.

      This implies that Musk knew the potential downside but wanted to see what would happen. They will learn a lot about the damage done to Stage 0. They probably couldn’t get away with testing Stage 0 like this further into testing.

      Time will tell how fast they can make repairs and install the mitigation measures. Hopefully months instead of waiting until next year.

      1. What we have here is the case where the rockets get churned out at a much faster rate that the launch infrastructure. Now that may have been true throughout history, we don’t see that with SLS but so far SLS hasn’t blown up its launch pad. But the fact of the matter is that you don’t see that issue typically because the NRE investment on pad development is usually a one-time or few time events and it is totally reused for each subsequent launch. In this ONE case we’ve had the inverse because the rocket is so damn big. This is going to take a significant time to fix because there isn’t an assembly line turning out Stage 0s. What’s funny is that if SS/SH were launched from *mobile* launchers we’d have an assembly line for those as well and there’d be plenty of Stage 0s in the wings awaiting final assembly and available for mods just like SS/SH.

        A mobile launcher for this would be a technological marvel no doubt. Not holding my breath…. 🙂

        1. What we have here is the case where the rockets get churned out at a much faster rate that the launch infrastructure

          Dunno David they had 2 and half year to improve on this it was a choice. They did buy a water deluge system they didn’t use/install which might be a costly mistake.

          I finally saw the article they gave up on refurbishing the Oil platform to be a launch platform and sold it in the past year. Which may be a bigger mistake. I would love to see what the thinking was that the Oil platform retrofit wouldn’t work but launching the largest rocket in history off a concrete platform with nothing to dampen the noise vibration was going to be fine. Launching the full stack from Boca Chica, is not going to have a long life time. Maybe they should start churning them out at Canaveral.

          1. It’s time to stop launching reusable rockets from the beach. Large stretches of exposed granite and basalt are available in Utah and Nevada. Jackass Flats is handy to Las Vegas.

          2. Don’t think they want a site north of Vanderberg either. With the Super heavy mission profile something close to the ecliptic is preferred. Though Rands presence is equator

          3. There’s no such thing as “closer to the ecliptic” on the surface of the Earth. The ecliptic is the plane of the Earth’s orbit around the Sun, and moves with the the fixed stars due to the Earth’s obliquity. Stable orbits with reference to the Earth’s surface only occur within one-half radius of the Earth’s Hill sphere. That’s why GEO is possible.

            Rand’s ELEO thing, if I understand correctly, is plausible because low equatorial orbits pass over the launch site once every orbit, so many times a day, where as inclined orbits precess. So if you had a high traffic fuel depot in LEO, that’s where you’d want it. Unfortunately, there are only three places where the equator crosses a continental east coast: Brazil, Kenya/Somalia, and Borneo. Not great real estate. Ocean platforms are largely untested (Sea Launch, and that old Scout platform off the coast of Kenya). I keep remembering “Tom Swift and His Ocean Airport.”

          4. Oh, look! I made a dumbass mistake of my own! They’re called the Fixed Stars because the Earth’s axis points to a fixed spot in the sky. Obliquity is defined by the fact that the Earth’s axis points to a different spot in the sky than the Sun’s axis. That doesn’t change anything, though. Unless I’m dumber than usual today.

    1. People should not trust their children’s education on a governmental bureaucracy/radial left teacher unions.
      It seems home schooling has changed and there is more of it.
      Also conservative always wanted a weak US President- they got that.
      And China taking over UN, so, globalism is dead.

      1. If we could only get UN housed in Beijing.
        It’s average temperature is about 0 C- they might even freeze to death. Or at least be more sympathetic to China’s effort to warm the planet.

  31. Sitting here tonight wondering if some of the N1’s issues were not just the rocket but because it also got damaged by pad debris?

    Anyone know? Lost in the annals of the Soviet?

    1. Probably not. It had a 3-way flame trench. The engines just weren’t good enough. Launch 5 (with the new engines) might have worked. They certainly work now, after 45 years in storage. (The one that RUDed on Antares was modified by AR; the ones on Soyuz 2.1v seem to work fine.)

          1. It’s a pretty good explanation. There’s still no good detail on naphthyl that I can find. In the US, naphthyl is basically cooked from mothballs. I bet “naftil” is not the same word.

        2. In brief, AR added gimbal steering, replaced the ancient electronics, and tuned the engines to use RP-1 instead of either RG-1 or T-1. I would guess that last is what caused the Antares RUD. Kuznetsov also made all the R-7 engines, which have run on RG-1, Syntyn, and now naphthyl (I don’t know about T-1). Kuznetzov invented the stratified combustion rocket engine.

  32. Instead of talking about Musk’s “huge mistake” in not following the conventional wisdom (which *is*, in fact, his “secret sauce), let’s wonder where the actual mistake was. The FAA approved this launch. That means someone who could do the math reviewed the calculations and agreed the Fondag should survive at least one launch! What *actually* happened? We’re all guessing, some with expert knowledge, others with fairy tale science. Get a kid’s sand box. Fill it with fine sand. Drop a fragile plate on it. Get a footstool and cut a hole in the top. Direct your garden hose, on stream setting, through the hole. What happens? Tilt it at an angle. What happens. Does the plate break? Does the spray over the edge of the plate dig out the sand at the periphery, and then underneath? Something broke the concrete in an unexpected way. SpaceX and FAA didn’t see it coming. People here who think they did are various kinds of broken clocks.

  33. I’m beginning to align with the notion there was an undetected flaw in the Fondag pad, which was preset for failure by the static fire. A second static fire would have cracked the pad, but there was no static fire, so…

    I don’t know if it’s possible to pour a flawless concrete pad that big. Anyways, next launch, whenever, will have a liquid cooled flame diverter over the new concrete pad. I know it’s possible to cut a 10,000 sq ft granite slab with existing technology, and then move what would be a 10,000 ton solid object. But I don’t know if granite would do the job better than concrete. I wonder what’s the biggest piece of tantalum hafnium carbide you could get? My Dad was an expert about this stuff, but he’d dead now, so I can’t call him up and ask.

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