SpaceX Falcon 9 historic landing thread (1st landing attempt & most recent missions)

Oh wow George that guy is hilarious!

Ha ha! That was pretty cool! Gotta love the enthusiasm of the Everyday Astronaut, and the drone angle from the SpaceX feed was awesome. Can’t wait to the Mk1 and Mk2 prototypes and then the real thing.

What a great test flight. It was nice to see how well controlled the bird was. Minor TVC control inputs and almost no cold gas thruster input. Very delicately done. Great work SpaceX .

Now I’m gonna have to build a Star Hopper... I’m thinking to upscale a Big Daddy, and put a blunted nosecone on it, keep it low and slow with a small vented chute on it....Great job by SpaceX, and Tim Dodd The Everyday Astronaut’s reaction was pure honest excitement!

Photo from Elon Musk


New video by Tim Dodd, various views and slo-mo.

Did anyone see the latest Everyday Astronaut video? It dropped today and at the end you can clearly see a tank flying out of the scene, to the right, once the Starhopper had landed and was throttling down. It was obviously a pressure vessel as there were openings at either end, opposite each other, and gas was streaming out propelling the tank as it flew through the air.

Scott Manley's take on the flight, and some issues that occurred. Including the COPV tank that came off at landing and thrusted itself end over end. Also, he suspects the engine was having a mechanical problem near the end (change in flame color) and may have caused a harder landing than intended.

Does he have any proof, evidence, or source, or is it his normal camera eye speculation?

georgegassaway said:

Scott Manley's take on the flight, and some issues that occurred. Including the COPV tank that came off at landing and thrusted itself end over end. Also, he suspects the engine was having a mechanical problem near the end (change in flame color) and may have caused a harder landing than intended.

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Hmm, if you watch the video in post 3568 (the drone footage) you can see the change in flame color begins right when the flame contacts the ground, starting at the tail of the flame and working its way upward. It seems just as likely the change in color is caused by dust being entrained in the exhaust plume and burning. In the attached screenshots you can see that on ascent, the portion of the flame in contact with the dust cloud changes color to orange. So it seems likely that the same thing happened on landing, rather than an issue with the engine. But of course I'm just guessing like they are.


Tony

first image is ascent, second is descent:

First image has no yellow flame in the exhaust from the motor, it's dust farther down.

Second image has yellow flame right out the nozzle. The source very likely to be internal (motor bits getting consumed), not external, as Manley explained.

georgegassaway said:

First image has no yellow flame in the exhaust from the motor, it's dust farther down.

Second image has yellow flame right out the nozzle. The source very likely to be internal (motor bits getting consumed), not external, as Manley explained.

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In the second image, could they just have throttled down the engine by throttling oxygen further than the LNG, leading to incomplete combustion? To my completely non-expert eyes, it looked like a Bunsen burner when you close off the air port. That said, I'm not sure whether that or engine bits being consumed is more likely to survive Occam's Razor.

Another Starship question: They have an enormous cargo area (AIUI Starhopper has full size tanks, so everything else is cargo). It's also supposed to replace Falcon 9 as a primary "satellites to orbit" vehicle. With a steel shell, how do they get the satellite out and then put the nose cone back on for re-entry? For human spaceflight, it all makes sense--no need to really get anything out. For cargo-to-orbit purposes, I'm scratching my head.

Back when the Starship was called the BFS there was an artist depiction of it releasing a satellite. Half of the nosecone opened like a trunk hood.

They just "beam" the satellites out.

georgegassaway said:

First image has no yellow flame in the exhaust from the motor, it's dust farther down.

Second image has yellow flame right out the nozzle. The source very likely to be internal (motor bits getting consumed), not external, as Manley explained.

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Hmm, the colors are identical in both ascent and descent. So you have two choices, it's dust being entrained in the exhaust plume, or the 'bits being consumed' by the motor that produce the exact same color as the dust did on the ascent. And somehow those bits weren't important enough to cause the motor to go kaboom.

I'm with boat geek on Occam's razor - I'll go with the dust.


Tony

(FWIW - I asked a SpaceX employee who works on the Raptor engine and they thought the dust scenario was the more likely of the two.)

this animated gif shows how the color change starts at the tip of the exhaust plume and works its way up, if it were bits coming from the engine, it should be the other way around:

manixFan said:

this animated gif shows how the color change starts at the tip of the exhaust plume and works its way up, if it were bits coming from the engine, it should be the other way around:

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Note, the exhaust velocity of the Raptor is so high, that it wouldn't be possible to see that difference in direction in a regular camera. It is conceivable that some engine parameter changes, that affects the plume tip first, with the appearance that something travels towards the engine. The simplest example of that is the plume tip getting closer when the engine throttles down.

That being said, I don't think that this is an example of the flame getting "engine rich". We've probably seen that already on the first Raptor video, where the plume develops a green tint before shutdown, indicating copper ions from the chamber in the exhaust. The bright yellow flame from this Raptor flight is consistent with black body radiation from small particles. This could be caused by soot particles from getting fuel rich, or as it looks in this case, from dust particles getting heated to incandescent temperatures.

Reinhard

Cropped photo from BocaChicaGal on NASAspaceflight forum. Source:
https://forum.nasaspaceflight.com/index.php?topic=48895.msg1997879#msg1997879



What you are looking at is the first prototype of "Starship", with the upper section being mated to the main body. It's undergone a major design change aerodynamically. Instead of three fin-legs, two of which would be hinged to fold upwards for re-entry, now it's just two fin-things (not wings as we think of them), still hinged to fold upwards to some amount for re-entry and some other maneuvering. And SIX short legs. The canards area bit different too.

Currently it has three Raptor engines mounted in it, but they may not be in flyable condition. Musk has said it will be flying by the end of October, so.... December?

Saturday the 28th, Musk will make a long-planned announcement about Starship and future plans. He sort of does this every year. His address will be at Boca Chica, with the prototype in full view. Crews have been working like crazy to get this prototype assembled in time for this announcement. Assembled not the same as ready to fly. "Hopper" took months.

I'll be at work when he does it, and do not have any link for any "live" source. but I expect some will have it. Sorta wonder if Tim Dodd (Everyday Astronaut) might livestream it.

I held off posting any news on this development since it was uncertain what was going on, and lots of speculative drawings, some of which were close and some of which not. Also there is prototype #2 being assembled in Florida. It looks to be built in better quality. This one is planned to fly up to about 10 miles, and I expect them to attempt the tricky transition from "belly-flop" re-entry mode, to pitch-up and stabilize itself into taildown mode for landing. I'm still leery of how they are going to pull that off, it's a far more difficult thing to do aerodynamically and as a rocket vehicle than most realize. Too many think because they do it so well with Falcon-9, it's no big deal with this. but Falcon-9 has the steerable grid fins, this has no effective aerodynamic steering at all once it starts to fall tail first. First time they do try to transition from belly-flop to land tail-first, I give it a 50-50 chance of landing close to where intended, if it lands safely at all.

Video by Tim Dodd, about the changes (as of what was sort of known/speculated days ago).


EDIT - adding a video by Scott Manley:

This looks like steam punk rocketry.

The presentation will be at about 7 PM, Central time. SpaceX will livestream it via Youtube.

For those who didn't slog thru the whole thing, here is "Elon Musk's Starship Announcement in 8 Minutes"


I think Elon Musk's best speech ever could be for the 2020 presentation if he would say "Ladies and Gentlement, our presenter tonight, Gwynne Shotwell" (she's the president and COO of SpaceX, an adept speaker). Here's a 16 minute clip from her presentation and Q&A at the 33rd Space Symposium.



Scott Manley's take:

When SpaceX resumes flying late next week, it looks like they will have their second fairing catcher ship onhand.



Recently " Go Ms Chief" was outfitted with the same arms as "Go MS Tree" (formerly named Mr Steven) has.

Next F9 launch is for another batch of Starlink Satellites, Starlink-v1 Flight1. NET launch date Oct 17th. So, hopefully both fairing halves will be caught. That will leave only second stages as expendable.

Occupational hazard: I look at that picture and had two thoughts:
It must be a pain in the butt to dock the fairing catcher boats with those giant arms.
I wonder if my old company designed the tugs in the background (answer: likely no).

boatgeek said:

Occupational hazard: I look at that picture and had two thoughts:
It must be a pain in the butt to dock the fairing catcher boats with those giant arms.
I wonder if my old company designed the tugs in the background (answer: likely no).

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I wonder how easily those fairing catchers would roll. They look like they have a high center of gravity.

mpitfield said:

I wonder how easily those fairing catchers would roll. They look like they have a high center of gravity.

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Roll as in roll over? Not likely. The pipes are somewhat heavy, but those boats are designed to carry pretty heavy loads. You can see from how much blue bottom paint is above the waterline that it could carry quite a bit more. Ballparking from the pictures, they could load another 2' of draft or so, which is around 250-300 tons. If there were no arms on the boat, they could likely carry that with the center of gravity of the extra cargo 6'-8' above the deck. I'd have to make some rash assumptions about arm weight and CG to figure it out for certain, but I don't think it would be an issue. Also, I'm 100% sure one or more regulatory agencies were involved in this conversion and that they would have done some kind of stability calculations.

On the other hand, roll enough to be uncomfortable or dump the fairing off the side? Totally possible depending on the sea state and where the waves are coming from. These boats are pretty shallow draft, so it will tend to roll harder. Waves from the bow or stern wouldn't be too bad. Waves from the side, especially 6'-10' or more would be Not Fun.

It’s been something like 3 weeks since the last SpaceX news. Aren’t we all supposed to be flying on Starships to Mars by now? What the heck is going on?

ThirstyBarbarian said:

It’s been something like 3 weeks since the last SpaceX news. Aren’t we all supposed to be flying on Starships to Mars by now? What the heck is going on?

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Regardless of his Twitter timelines, Space is hard. There are good people working there, but they can't rewrite physics.

georgegassaway said:

Next F9 launch is for another batch of Starlink Satellites, Starlink-v1 Flight1. NET launch date Oct 17th.

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THat's been delayed, apparently due to FCC issues in granting a license for all those satellites. There are different that the prototypes that flew ealeir this year. Anyway, now looking like late November, but could be longer.

In Flight Abort test of Dragon-II is supposed to happen by the end of December.

Dragon-II Abort Static firing, the same kind that explode-anomalied in April, is supposed be this Saturday.

Early in September, Elon Musk said the MK1 Starship (prototype built in Boca Chica) would fly by the end of October. They got it crudely "assembled" barely in time for his address at the end of September, then had to disassemble it to install a lot of the "real parts", like actuators for the folding wing/fins, and legs with shock absorbers. And other stuff for it to fly. Maybe the 3 Raptors are in it now, maybe not. Maybe it will fly by the end of November, maybe not. It's supposed to fly over 12 miles high. I suspect they will do a simulated belly-flop descent then try that unique maneuver to pitch to vertical and land. It sounds like this maneuver is supposed to happen very close to the ground, like under 2000 feet, maybe 1000 feet. So if there's a little error, it may crash. They need to test out that maneuver as soon as they can, to see if it works. Because if it does not, they will probably have to redesign it yet again. If it were me, I'd want to do that maneuver 4000 feet up, to allow a fudge-factor in case it does not get vertical under control, thrusting, as fast as a low altitude transition needs. But that would presume enough fuel onboard to burn the engines that long. Nobody really knows how much fuel MK1 has, or most importantly how much in the "header tanks" that will be used for landings (think of them as "reserve tanks" inside of the main tanks)

Interesting/Odd news. The next F9 "Polar orbit" launch by SpaceX will be from KSC, using a special launch corridor to the south (over Cuba or very close to Cuba). So, SpaceX may do all polar launches from KSC from now on. So, the Vandenberg site might have launched it's last Falcon. Also looks like only one other launch scheduled at Vandy, by anybody. Sorta odd.

georgegassaway said:

...It sounds like this maneuver is supposed to happen very close to the ground, like under 2000 feet, maybe 1000 feet. So if there's a little error, it may crash. They need to test out that maneuver as soon as they can, to see if it works. Because if it does not, they will probably have to redesign it yet again. If it were me, I'd want to do that maneuver 4000 feet up, to allow a fudge-factor in case it does not get vertical under control, thrusting, as fast as a low altitude transition needs. But that would presume enough fuel onboard to burn the engines that long. Nobody really knows how much fuel MK1 has, or most importantly how much in the "header tanks" that will be used for landings (think of them as "reserve tanks" inside of the main tanks)....

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That altitude for the rotation sounds absolutely crazy, though I know SpaceX has pulled off the crazy/impossible before. Just spitballing here, the terminal velocity in belly flop mode is maybe around 100 ft/s (similar to a skydiver). 2000 feet at rotation gives 20 seconds to rotate and stop. Even if they can stop in 5 seconds (seems fast, 2/3 G), that's 15 seconds to pull a 90-degree rotation of a 160-foot object. That's going to take a lot of fuel/cold gas in the thrusters. Seems like they'd be better off carrying more propulsion fuel and doing a slower rotation so they can stabilize after an error. I know it's not exactly the same, but I can't help think about the problems the Osprey had in changing from helicopter mode to airplane mode.

Although another thought, maybe the Raptors don't throttle down as much. That would make it harder to tune descent speeds.

As always, I welcome corrections.

Fuel slosh in the tanks will be wicked during that maneuver. It will be a bit of a challenge taking that into account, but should be manageable.

OverTheTop said:

Fuel slosh in the tanks will be wicked during that maneuver. It will be a bit of a challenge taking that into account, but should be manageable.

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For a "normal" rocket, yes. The "header tanks" however, will probably be full or close to it. Think of a small tank inside of a big tank, in the middle of the tank.