totm nov 2023 SpaceX Discussion Thread

[sevenperforce]

26 minutes ago, bearnard1244 said:

Also, I`ve heard that Space X and NASA are planning to build a special station on the surface of the Moon which will contain the plant that will refuel space ships that travel to Mars. Maybe it`s connected somehow, but I don`t know whether it`s plausible or not. 

There's no way to source carbon on the Moon, so this can't be used to refuel Starship. However, NASA does want to try and source water ice from the moon to refuel hydrolox ships for Mars missions. That's why Artemis is targeting the lunar south pole.

[KSK]

21 hours ago, zolotiyeruki said:

As I recall, it wasn't a dropped tank, it was a change in the voltage spec for some instrument or tank heater.

It was both. Dropping the tank knocked the drain valve slightly out of alignment which meant that it was taking overly long to drain the propellant after a tanking test.  Given that the drain valve was only used on the ground (for those tests) and not in flight, they figured it would be OK to use the tank heaters to raise the pressure inside the tank and help clear out the residual propellant.

I forget the exact details here but I think a change in voltage spec for the heater meant it got stuck on, which led to the temperature in the tank going way too high and eventually leading to the coating on the heater element being charred away, leaving bare wires in the tank. Unfortunately, the whole system was never meant to go above 70 degrees and the temperature sensor was rated accordingly. Hence there was no indication from outside that the inside of the tank had been cooked.

Bare wires inside an oxygen tank went about as well as you'd expect.

 

Edited December 17, 2020 by KSK

[Clamp-o-Tron]

2 hours ago, sevenperforce said:

There's no way to source carbon on the Moon, so this can't be used to refuel Starship. However, NASA does want to try and source water ice from the moon to refuel hydrolox ships for Mars missions. That's why Artemis is targeting the lunar south pole.

As an addendum- the hydrolox or LH2 for a Mars mission wouldn't be used to refuel a transfer vehicle from the Moon or even Moon orbit. The less dV-intensive option for the main transfer vehicle is either in EML1, an eccentric GTO-like orbit, or just LEO after aerobraking the tanker down from Moon orbit.

This doesn't really NEED to happen for a Mars transfer vehicle, that LH2 (and possibly LOX if they are eschewing the NTR path) can be shipped up from Earth. In this hypothetical future in which Copernicus NTV part 2 happens, Moon refueling would require that making that propellant and shipping it down to the transfer vehicle be cheaper than just shipped up from Earth on New Glenn or something, which would be impressively hard.

I believe that the current Artemis ISRU plans are more about creating enough propellant to refuel a lander than an entire transfer vehicle- the infrastructure required probably won't be in place in time for NASA's planned mid-2030's Mars expedition. This all assumes that Starship doesn't do Mars first, and I'm not entirely convinced that it will be able to do Mars anytime before 2028.

6 hours ago, bearnard1244 said:

So, guys, it`s very pleasant to chat with you here and I wanna share with you some information about the latest inventions from Space X. Musk has determined that the water ice locked in the Martian substrata is fuel. As such Musk is building the first industrial-scale water separator, smaller than a submarine, to create breathable Oxygen and Hydrogen which can be liquified and turned into fuel. After which the astronauts can drink the dirt.Now if Musk could just figure out how to launch the water separator and Hydrogen and Oxygen containment tanks and processing hardware that all together is about as large as a submarine at least.  What do you think about that statement of Elon Musk?

Well, Musk himself didn't determine that  . ISRU for water ice on Mars has been around for a while.

Water ice is certainly useful for lots of things, be it just water, O2, or H2. H2O and O2 can't power a Starship, though, it needs Methane (CH4), and thus carbon. You can get that carbon from the 95% CO2 Martian atmosphere, and use the sabatier process to turn CO2 and H2 into CH4 and secondary H2O. To get that water, there are some non-polar places on Mars with some pretty large underground ice deposits (link), and that could be mined.

Industrial-scale water electrolyzers exist already, and in much bigger form-factor than any Martian reactor could be.

I really doubt that a Martian ISRU setup meant to fuel several Starships would take up as much room as a submarine. For reference, here's a good image of the ISS's Sabatier, along with a small commercial water splitter:

The output would certainly have to be scaled up a lot, but the sizes are pretty small. Also, Starship is pretty damn big so they could fit a lot of equipment in it.

 

[tater]

 

MVP: Octograbber

The landing looked OK, mighta been sea state issues.

[RyanRising]

What, again? Maybe we should start formatting it as SpaceX instead of SpaceX. Hope that booster’s fine! 
 

EDIT: Also, unrelatedly: does anyone have speculation on how dirty the Superheavy booster will get? Obviously there’s less soot from the fuel than Falcon 9, but I don’t imagine it’ll stay sparkling clean.

Edited December 17, 2020 by RyanRising

[Scotius]

1 hour ago, RyanRising said:

What, again? Maybe we should start formatting it as SpaceX instead of SpaceX. Hope that booster’s fine! 
 

EDIT: Also, unrelatedly: does anyone have speculation on how dirty the Superheavy booster will get? Obviously there’s less soot from the fuel than Falcon 9, but I don’t imagine it’ll stay sparkling clean.

"Knife collectors that own carbon steel blades sometimes force a patina onto the blade to help protect it and give it a more personalized look. This can be done using various chemicals and substances such as muriatic acid, apple cider vinegar, or mustard. It can also be done by sticking the blade into any acidic vegetable or fruit such as an orange or an apple. "

Time to hose the SN. 9 with orange juice

[sevenperforce]

Because I apparently cannot stop making these....

[JoeSchmuckatelli]

Sliding shoe should be OK for a concrete pad - but earth, regolith, mars might be a sticking point 

[ExtremeSquared]

3 hours ago, JoeSchmuckatelli said:

Sliding shoe should be OK for a concrete pad - but earth, regolith, mars might be a sticking point 

Make it a spike, then. Nobody likes it when their tent blows away.

[kerbiloid]

A Falcon Heavy Double ASDS.

(A documentary photo)

Spoiler

 

[YNM]

2 hours ago, kerbiloid said:

A Falcon Heavy Double ASDS.

(A documentary photo)

It's narrower than the barges...

EDIT : These are closer to the dimensions you'd want...

Spoiler

 

Edited December 18, 2020 by YNM

[kerbiloid]

1 minute ago, YNM said:

It's narrower than the barges...

The accuracy should be improved.

The Falcon Heavy lateral boosters are parallel. So, two FH landed aside.

[magnemoe]

12 hours ago, sevenperforce said:

Because I apparently cannot stop making these....

Liked that one, having an hinge on the outrigger is pretty simple and can be combined with an shock absorber pretty easy, make the outer part longer for more effect.
At this point the main absorber might be redundant. you have one in the heal and on in the toes anyway. 
Use the height of the heal to level it after landing. Probably an way to release the toe part if it land on an rock or something. 

[Lukaszenko]

What's wrong with Falcon 9- type legs? Or, at least legs on the outside.

Seems like it would solve a lot of problems.

Why are they insisting on legs on the inside?

[Clamp-o-Tron]

6 minutes ago, Lukaszenko said:

What's wrong with Falcon 9- type legs? Or, at least legs on the outside.

Seems like it would solve a lot of problems.

Why are they insisting on legs on the inside?

Thermal protection. Starship will have at least a few legs fully exposed to reentry heating, much more than F9 legs have to handle with their lower velocities and higher entry angle.

I suppose Starship could use those F9-style legs with TPS tiles on the outward-facing side, which is just the heatshield seams they want to avoid.

[kerbiloid]

Spoiler

  

20 hours ago, sevenperforce said:

Falcon 9 has too much pressure; Starship has too little pressure

The former suffers from overpressure, the latter works under pressure, and even the room for the crew is called "pressurized".

Say, the pressure gets removed. Is it OK?

No. They start screaming "decompression"

A world of violence,,,

 

Edited December 18, 2020 by kerbiloid

[tater]

Launch tomorrow, I guess.

 

 

[sevenperforce]

13 hours ago, ExtremeSquared said:

Make it a spike, then. Nobody likes it when their tent blows away.

Ground-penetrating legs could cause problems if there was lateral velocity on touchdown. You want the legs to prevent tipover, not exacerbate it.

4 hours ago, magnemoe said:

Liked that one, having an hinge on the outrigger is pretty simple and can be combined with an shock absorber pretty easy, make the outer part longer for more effect.
At this point the main absorber might be redundant. you have one in the heal and on in the toes anyway. 
Use the height of the heal to level it after landing. Probably an way to release the toe part if it land on an rock or something. 

I don't want to put a shock absorber in the "toe" for two reasons. First, the shock absorber need to be inline with the vehicle to reduce the bending moment on the skirt. Second, and more importantly, you can fit more shock absorbency and a longer stroke length with less weight in a separate system. You don't want too much complexity in the part of the leg that is already going to have to rotate and lock into place. Stroke length is the most important factor for a shock absorber system.

I'm envisioning the "heel" as having nothing more than a spring and an emergency crush core, to bear the primary static load just like the current legs. The dynamic load is borne entirely by the pneumatic piston.

3 hours ago, Clamp-o-Tron said:

Thermal protection. Starship will have at least a few legs fully exposed to reentry heating, much more than F9 legs have to handle with their lower velocities and higher entry angle.

I suppose Starship could use those F9-style legs with TPS tiles on the outward-facing side, which is just the heatshield seams they want to avoid.

And even if you use F9-style legs with a heatshield seam, you end up with the heatshield tiles directly contacting the ground at the toe, which again is something you want to avoid.

[cubinator]

41 minutes ago, bearnard1244 said:

Do you think that statement of Musk is plausible?

I think plenty of uncrewed missions to Mars are possible within two or four years with Starship, but I don't think anybody's going to Mars themselves before 2030 with better than a 50% chance of surviving. There is much that is unknown about entering the atmosphere at Mars and returning to Earth, and we still have yet to see how the Starship handles that. Luckily the Starship will be able to fly with great frequency and we'll quickly be able to learn how to make the arrival at Mars and the whole stay safe.

The Moon is quite reachable, and we can absolutely start sending people there and building bases fairly soon. The Moon is a good place to test water mining systems (which has never been attempted on another planet) and food growth for sustaining long excursions away from Earth.

[JoeSchmuckatelli]

2 minutes ago, cubinator said:

I think plenty of uncrewed missions to Mars are possible within two or four years with Starship, but I don't think anybody's going to Mars themselves before 2030 with better than a 50% chance of surviving. There is much that is unknown about entering the atmosphere at Mars and returning to Earth, and we still have yet to see how the Starship handles that. Luckily the Starship will be able to fly with great frequency and we'll quickly be able to learn how to make the arrival at Mars and the whole stay safe.

The Moon is quite reachable, and we can absolutely start sending people there and building bases fairly soon. The Moon is a good place to test water mining systems (which has never been attempted on another planet) and food growth for sustaining long excursions away from Earth.

So  -- out of pure speculation: let's say that someone builds a water miner that would function on the Moon or Mars... How does Starship deploy it, much less use it?  Internal crane?  Even then, the unit is likely to have to crawl around and prospect a bit  - even if we land on a site with known 'good ore concentration'.  After that, it would have to reconnect to Starship in some manner to refuel Starship (presuming that's the water-miner's purpose) - just for the proof of concept launch, land and return.

That's a lot of stuff to invent and test in 10 years.

[paul_c]

There's 4 options -

1.  You're stuck with the location you landed it in
2.  Take off the whole Starship and land it again somewhere else
3.  A sub-module detaches and flies there
4.  A sub-module has wheels and drives there

I suppose there is the 5th option, that its transportable by being manually lifted up...but I doubt it would be light enough, even on Moon's 1/6 gravity, to do that.

I am going to guess, they'll have a pipe back to Starship - makes more sense than flying/driving the whole module back to unload. 

Option 1 makes a lot of sense if they can send a "scout" to survey the suitability of the area. Especially since its down to geology etc and is much more involved than a scanner in KSP! I think they'd get it more/less right, because it has to be somewhere, so just make it land there. They can do precision landings and have been since the early Apollo missions.

[RealKerbal3x]

I got this from the LabPadre discord server. It looks like SN9's most damaged flap did some actuation testing.

If the motors can still move the flaps, that's a good sign. It probably means damage is minimal. Hopefully they can replace the flaps and be good to go!

[magnemoe]

1 hour ago, paul_c said:

There's 4 options -

1.  You're stuck with the location you landed it in
2.  Take off the whole Starship and land it again somewhere else
3.  A sub-module detaches and flies there
4.  A sub-module has wheels and drives there

I suppose there is the 5th option, that its transportable by being manually lifted up...but I doubt it would be light enough, even on Moon's 1/6 gravity, to do that.

I am going to guess, they'll have a pipe back to Starship - makes more sense than flying/driving the whole module back to unload. 

Option 1 makes a lot of sense if they can send a "scout" to survey the suitability of the area. Especially since its down to geology etc and is much more involved than a scanner in KSP! I think they'd get it more/less right, because it has to be somewhere, so just make it land there. They can do precision landings and have been since the early Apollo missions.

I say 1) with the issue that you need an way to refuel the starship so it can do the second jump. 
An truck can do 4) have the tanks on an pallet so you can use the truck for other uses, you will fly in the truck on the cargo mission earlier. 

thought about 5) but it will be an too large transporter, might be relevant down the line. the starship transporter they use now is modular and not that heavy as in < 100 ton. 

[tater]

9 am EST:

 

[RealKerbal3x]

SN9's crunched forward flap got removed! (also from the LabPadre discord).