The Great Ongoing Space Exploration Thread

Miscellaneous and Personal Stuff I Must Share
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There’s static tipping and dynamic tipping. Static tipping can be solved just by appropriate landing site selection (i.e., not at a 30 degree angle). Dynamic tipping means having no lateral velocity on landing.

Lunar gravity makes the dynamic tipping problem worse. The mass of an object is independent of gravity, so the momentum for a given lateral velocity is also independent. But lifting the object against the force of gravity does go down as gravity decreases. So the momentum has an easier job working against the tipping force.

However, large objects are harder to tip for a given lateral velocity. If something lands with a 1 m/s velocity, a tiny probe will go tumbling end over end, while a huge lander won’t notice. Also, HLS has a lot of low-slung mass (mostly in the remaining propellant), which also helps.

But mainly, the solution to not tipping is to land with no lateral velocity. SpaceX has proven capable of this with the Falcon 9 landings, which have to deal with weather and a moving barge. The moon should be a piece of cake in comparison.

If they really need to, they can make some super wide landing legs. The ones we’ve seen so far aren’t final.

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Since the moon is airless you couldn’t come to a landing horizontally (unless you want to try to skid to a halt from about five thousand miles per hour). I think what @Common_Tater was thinking of is called a Belly Lander (Embarking - Atomic Rockets ). The tankage is arranged horizontally instead of vertically but it still lands vertically by rocket exhaust.

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A Raptor engine doesn’t pass its test.

(You have to look in the user comments to get a post of a tweet with the video.)

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SpaceX blows up a lot of Raptors. A decent selection from a year ago:

Of note: green flame represents “engine-rich combustion” (as contrasted with the usual fuel-rich combustion). The green comes from the internal copper jacket burning away.

To be sure, the recent one was more energetic than most. They’ll probably have a bit of repair work to do. But they’re also in the process of developing Raptor 3, so we should expect plenty more of these. Probably a portion of these are intentional in the sense that they drove the engine to failure.

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Oh that was a proper explosion. Looks like a fair bit of damage could have been done to the test stand - though I suppose they must build with this sort of anomaly in mind.

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From the Starliner media conference today, the launch is still planned for Saturday, June 1. However they will conduct a final flight readiness review on Wednesday, before rolling to the pad.

The helium leak is greatest when pressure is removed, and smallest when pressure is applied. That is common in multiple seals, for which pressure tends to close the leak.

The amount of the leak is inconsequential, and NASA has launched other vehicles with similar leaks, including Shuttle and Crew Dragon. They ran the worst case where the seal blows out completely, and they still have sufficient margin.

Starliner is designed to be operated safely with up to 4 manifold leaks at 100 times the current rate. The seal cannot be replaced because the manifold is shared with hypergolic propellants, which require special handling.

They are running contingency scenarios where they lose the thrusters affected by the leak, plus two other banks of thrusters on the same side. That could lead to difficulty in controlling attitude during maneuvering and reentry. It’s an extremely remote possibility, but flight rules require the spacecraft be able to function under those conditions.

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Weren’t we discussing at some point that Starliner had failed several backups and was now going to fly with zero redundancy?

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A lot of this was also discussed in this latest episode of the YouTube series “The Space Race” (https://youtu.be/eJ3dsXP839U?si=NpXckrmsll4b96E6). The questions raised in both the article and the YouTube episode are quite interesting IMHO, but I have to assume that the challenges discussed have been or are being addressed by the relevant experts

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The latest Starlink launch (just completed) makes 14 launches in a single month for SpaceX. Almost within a factor of 2 of “a rocket a day”.

This is also pretty neat:

The drone ship is basically spending all its time traveling. Just a few hours to drop off the rocket, refuel, and immediately back out to sea. Tonight, the ship wasn’t even in position just a few minutes before launch–they delayed the launch to the end of the window to wait for it to get into place. They’re going to need more drone ships to increase the cadence. Or maybe attach a couple of rocket engines to make them go faster…

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Starliner scrubbed again. Fault in the ground-based launch computers.

In other news, the astronauts will be flying without their luggage in order to bring a new urine recycling pump to the ISS. The old one apparently broke down.

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China doing some cool stuff on the far side of the moon:

Not the goddamn “dark” side.

The probe has an ascent rocket to return samples, which has reportedly already taken off for Earth. There’s also a mini rover, though I don’t think it’s done anything yet.

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Something totally amazing:

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Now to see if the heat shield survives reentry.

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A little over a year later, and Stoke has completed a hot fire of their full-flow staged-combustion (FFSC) methalox engine:

This is not a small feat. Only SpaceX has done the same. Other methalox engines are not FFSC, and the one other example of an FFSC engine (the RD-270) was not methalox (nor was it really ever completed). It’s very impressive that they got here in ~18 months.

They still have a lot of work ahead of them, but they seem to be a worthy contender in the newspace ranks. And the only one aside from SpaceX that is pursuing full reusability.

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Long way to go, but that is promising news. i get the strong feeling that having a viable competitor to SpaceX (which IMHO we don’t have right now) will be important to the future of commercial spaceflight.

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I don’t think there’s any danger of SpaceX going away or even acting monopolistic (they’ve shown signs of the opposite so far), but nevertheless the industry would be healthier with a good competitor. Unfortunately, almost no one outside of newspace is even acting like they want to be one. Both Ariane 6 and Vulcan are basically a joke compared even to Falcon 9, not to mention Russia, India, etc. New Glenn and Neutron are better but will just be Falcon 9 competitors, not Starship. And it will take them some time to even catch up with F9 in terms of cadence and internal costs.

SpaceX will put close to 90% of the world’s total mass to orbit this year, and this might reach >95% before it starts dropping. Even 98-99% is not impossible if the competitors are a little on the slow side.

1358

Some very strange things going on on the ISS. “Commander” appears to have had some medical incident. They’re giving him oxygen via a mask and seemingly trying to get him into a suit. Possibly there will be an emergency capsule reentry. Flight surgeon is talking about hospitals in Spain. Prognosis is relatively “tenuous”, though.

The current ISS commander is Oleg Kononenko, but they keep things very generic over the call so it’s impossible to know for sure who they’re talking about.

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I should add, it’s possible this is a drill or simulation of some kind… but the audio doesn’t give that kind of vibe. We’ll undoubtedly find out more soon.

ETA: Whew! Probably a sim:

Pretty interesting to hear, in any case. Don’t normally get that kind of visibility.

1360

Transcript of the audio:

So if we could get a commander back in his suit, get it sealed and step into procedure 5.180 for suited hyperbaric treatment, section three for oxygen post-splashdown, that would be my recommendation. How copy?

Copy. Understand that this is a best effort treatment, and so whatever you can do is going to be better than doing nothing. And just as an FYI, prior to sealing, closing the visor and pressurizing the suit, I would like you to check his pulse one more time. How copy?

Correct, yes. That would be, actually, Sif [sp?], you’re on this call. How much oxygen do we have remaining in minutes?

Perfect, so yes, then I would like you to have 100% O2 flowing via mask while you get the suit on. Prior to closing the visor and pressurizing, I’d like you to do a pulse check one more time, and then step into 5.180, section three.

Is there a way that the mask can be attached? So is there a way that we could get the suit over the head, have the visor open, and put the mask at least close to his face while you finish sealing up the suit, or is that not feasible?

Copy. Copy.

Well, I think at this point, because the hypobaric exposure is the big problem, and given his exam, I am concerned that there are some severe DCS hits, and so I would recommend trying to get him in the suit as soon as possible, and giving oxygen as best as able during that process, but the best thing would be to get him in the suit ASAP.

Thank you. Just as a FYI for you, I am still about one hour out from MCC-X. Unfortunately, we will need to keep doing the phone situation until I am able to be there. I am currently stuck in traffic.

While we don’t have other flight surgeons on call, while I am stuck in traffic, I can reach out to see if there’s anyone who can get there sooner than one hour. That being said, there really isn’t anything we could do in person that we can’t do over the phone at this point. Unfortunately, the prognosis for Commander is relatively tenuous, I’ll say, at this point, to keep it generic.

One thing, I don’t know if you got this message before, but I did find a, through Dan, I did find a hospital in Spain that has critical care facilities and hyperbaric treatment facilities. Would you like me to give you that hospital and their phone number again?

Okay, so that is San Carlos, S-A-N-C-A-R-L-O-S, in San Fernando, spelled the normal way, and that’s in the province of Cadiz, C-A-D-I-Z, in Spain. And that phone number is country code XXXXX . Again, that number is country code XXXXX. How copy?

Copy. In the meantime, I will continue my trek in. Otherwise, I will see if a flight surgeon can be there sooner, and then you are free to call me with any updates or any changes. If the crew do get suited and start the treatment and they make a call down, I would request to be updated at that point. Thank you very much. Anything else I can do for you, Sif? Thank you, bye.

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