totm nov 2023 SpaceX Discussion Thread

[Silavite]

On 4/29/2020 at 12:15 AM, tater said:

Here's the interesting solar power talk:

He is suggesting this using Atlas 551 as the LV. At the mass they are confident of achieving, they would need 58 launches to get to power at $1.77/kWh. That's of course only a number the US military might pay at a base in the middle of no place in AK, or something. Atlas 551 is ~153 million a pop. So 870t at a total cost of 8.874 B$.

Assuming that SS can get only 87t to MEO (150 to LEO) with no refilling. That's 10 SS flights. If they charged the same per launch as Atlas 551, that's 1.53B$. That drops the price per kWh to 30 cents. Still 3X what I pay at home. Of course MUsk has said that SS would be able to fly for a couple million a flight, but they need some markup, clearly. If they charged 50M$/flight, then the power cost is now competitive with what I pay at home.

So space based power might actually be doable with launch costs cheap enough. A few years ago I would have said, "yeah, space based solar was debunked years ago" but that's simply not true now, it might be possible.

I don't think this is a killer app for SS, what I am really getting at is that lower cost opens up possibilities that have been discounted, or no one ever seriously considered. Asteroid mining is another. The current entry costs are absurdly high to test anything... not at $67/kg they aren't, and the spacecraft doesn't need to be perfect for that cheap a price, if it fails, iterate and send another.

 

20 minutes ago, SOXBLOX said:

It's not that I have a problem with orbital tourism, I just see it as an attempt by spaceflight fans to find an economic justification for spaceflight efforts; something of which there is precious little. And don't you dare mention asteroid mining, I've heard all that before!

Spoiler

(Yes, yes... I know that Tater mentions asteroid mining at the end, but pretend you didn't see that!)

[tater]

Asteroid mining I think becomes a different thing when cost to orbit is low enough. Right now it's wishful thinking, but all the proposals are still in the "smallest possible spacecraft testbed" mindset for many hundreds of millions of $, not, "Keep it under 100 tons, and 10 million bucks, and let's see if it works!"

(a decent asteroid could be a counterweight for a tether, too)

[SOXBLOX]

Beamed solar power is definitely interesting, but it needs Cargo SS, not Crew SS. As does asteroid mining. So those won't really spark colonization. Oh, well. As noted by Winchell Chung, we suffer from an acute lack of MacGuffinite.  

[tater]

1 hour ago, SOXBLOX said:

Beamed solar power is definitely interesting, but it needs Cargo SS, not Crew SS. As does asteroid mining. So those won't really spark colonization. Oh, well. As noted by Winchell Chung, we suffer from an acute lack of MacGuffinite.  

Yeah, I'm all in for cargo at 10s of bucks per kg to LEO. Crew? Like I said, there's no place to live in space until you build it first.

Chicken and egg.

You need a reason for people, and robots (autonomous or teleoperated) only get better and better. Honestly, given his interest in autonomous vehicles, seems like the best thing to do for Mars (not my thing, but for the Mars colonizing people) would be to figure out how to have robots build a place to live, THEN send the people. Of course they need to have a reason to be there more compelling than dying on Mars.

BTW, the beamed solar in that talk is interesting because with the better panels that are ALSO 2 sided, and ALSO have built in antennas they can close the cost case for very limited terrestrial applications—and that was using a very expensive launch vehicle.

Edited June 24, 2020 by tater

[kerbiloid]

If the "P2P" means the idea of routine transcontinental passenger rocketjumps (opposed to the orbital tourism),
I believe that its actual purpose is not the passenger transportation itself,
but a ring of SpaceX launchpads/dropzones around the world to land the stages without catching them by barge and moving them back to the shipyard.

For the 3 m Falcon, the barge is 90 m long. If scale this 3 times up for the 9 m Starship, they should use an aircraft carrier to land it.
And they should have at least two, like ASDS now.

So, an alternative for the private carrier fleet is the sequence of launchpads/dropzones.
You place them one by one as a ring around the world and land the first stage on the next one to service, refuel, and reuse.

***

But the problems are that you need to rent the land, friend the govs, guard the base, and so on.
And all of that in various exotic places, including non-friendly ones.

So, a solution looks like "if you have a spaceport for us, you can be a part of our suborbital airlines route".
Like the airlines don't own the airports, just pay for parking and servicing.

Then starships and their first stages keep jumping from point to point, some of them with passengers, other with orbital cargo,
and the local spaceport owners care about the ground infrastructure instead of SpaceX.

So, the passenger rocketjumps are not a purpose but the way to make cheaper the cargo launches.

***

Of course, this can work when the flights happen enough often, comparable to aviation schedule, at least once per week (hi, Space Shuttle, you remember that).
Also this can work if there is a fleet of starships to have the spaceports busy.
To prevent bottlenecks, the fleet size should be comparble to the spaceports number. Maybe 2 starsships per spaceport at once.

***

An obvious first route leg is bidirectional domestic TexFlo/FloTex.
According to the Goggle Ёarth It's about 1700 km long.
For me, it looks appropriate for the 1st stage landing, and it's comparable to a regional airlines distance.

They need to jump across the oceans.

A set of ~1700 legs across the Atlantics includes Greenland-Iceland and Iceland-England.
Previously - Quebec/Newfoundland - Greenland.
Before that - Florida-New England and (parallel) Texas-New England.

Obviously prior to Texas is California.

To the west from California there are Vancouver and Alaska/Yukon.
And Hawaii. But they are 4 000 km far. So, either 4 000 km long jumps are accessible, too, or no Hawaii.

To the Alaska/Yukon they can jump either from Bering Strait or from the middle of Aleutian Islands.

Obvious next target is Japan.

1) It's 6 500 km far from Hawaii. But there is a midpoint, the Wake Military Island at 4 000 km from Hawaii.
It's just 6 m high, so will sink soon, but it has a military base, so probably they'll build a concrete island on top.
So just put bags on the pax heads, chain them to seats, and make them keep the heads between the knees, and they can happily pass through the tiny military fortress without seeing anything classified.
This means that 4 000 km long jumps make the S.Japan-Wake-Hawaii-California route accessible.

2) Both Bering Strait and Middle Aleutian Islands are tied at Kamchatka if use 1 700 km jumps.
Prior to Kamchatka there are N.Japan and S.Japan points.
If use 4 000 km legs, N.Japan can be reached from any point of Alaska Atlantic coast, and the Alaska coast can be reached directly from California.

Also the mentioned Newfoundland is at 4 000 km from England (and also ends with "-land" rather than Quebec), so a 4 000 km jump allows to avoid polar night flights through far and cold Greenland and Iceland.
Or they can jump over the ocean directly to the coast of Spain or France.

So, 1 700 km jumps are obviously viable (they're the natural SpaceX FloTex test distance),
but 4 000 km jumps will be highly desired by SpaceX, so they will put efforts to use them, too.

***

So, we are now at S.Japan/S.Korea.

Here a rre two probable routes though highly populated areas: continental China and Thailand-Taiwan (1 700 km legs).
Probably they want both for obvious reasons.

Thailand is also directly accessible from S.Japan/S.Korea by a 4 000 km jump.

Pakistan - Kolkata/Calcutta are two 1 700 km legs from Thailand.
Or a 4 000 km long Pakistan-Thailand jump.

Also Kolkata/Calcutta is 4 000 km far from Taiwan.

S/C.India is a side-step 1 700 km leg of the same route.

From Pakistan there is a 1 700 km leg to the Emirates, then 1 700 km to Baghdad, then 1 700 km to Istanbul.
Also Pakistan is 4 000 km far from Cyprus and S.Turkey.

***

The Chinese route from S.Japan/S.Korea is a 1 700 km leg to the Beijing/Shanghai, then either from the South or West (it's unlikely because of Himalayas and for obvious political reasons),
or from the North-West across Mongolia and various low-populated areas (it looks also unlikely).

So, the only viable continuation of the Chinese branch is a 4 000 km jump either from Kazakhstan, or from Pakistan.

This again shows that 4 000 km jumps is highly required for the whole project.

***

In the Kazakhstan they need two 1 700 km jumps or one < 4 000 km jump to reach it from either European part of Russia or Eastern Europe.
Or the same to reach it from Istanbul.

***

Between England/Spain/France and Eastern Europe/Istanbul there are two 1 700 km legs or a direct 4 000 km jump.
The midpoint, so a route hub is somewhere around Austria.
A side-step is North Europe.

***

But we forgot Australia _{(as usually)}.
Its Eastern coast can be accessed from Thailand or Taiwan in two 4 000 km jumps.
The midpoint is Eastern Indonesia.

To the East of Australia there is nothing but ocean. So, from Australia only to orbit.
Sorry, Aussies, you need almost 4 jumps to reach at least something beyond the Easter Island. But you chose this yourself.

On the other hand this means that the Easter Island is the midpoint between Australia and the heavens.

***

South America is accessible only in meridional direction.

Texas/California - S.Mexico ~1 700 km.
For obvious reaons unlikely one more 1 700 km leg to the South is accessible in near future, so either 4 000 km S.Mexico - N.Brazil, or 4 000 km Texas-Equador.

Next 4 000 km jump is S.Argentina.

***

From S.Argentina there is Antarctic peninsula.
It's cool.
Literally.

Then same Antarctic Victoria Land.

And, unexpectedly, ta-dam!, Australia.
Slippery Aussies, they found a detour. All they need is a couple of Antarctic spaceports, and - voila! - they're in Argentina.

***

Getting meridionally 4 000 km from Texas , there is nothing but frozen part of Canada.
Next 4 000 km is Far North of Russia. Then - Kazakstan, and both routes (latitudal and meridional) get connected.

***

So, the probable routes are (auxilliary are grayed):

California → Texas → Florida → New England + Newfoundland → Greenland → Iceland → England + W.France + W.Spain → nearly Austria →

→ Poland → Moscow → Kazakhstan
→ SW Turkey + Cyprus → 

→ Kazakhstan → Beijing/Shanghai → S.Korea + S.Japan
→ Emirates → Pakistan → Kolkatta/Calcutta + S/C.India → Thailand + Taiwan

Taiwan → S.Korea + S.Japan
Taiwan → E.Indonesia - SE.Australia

S.Korea + S.Japan → Wake → Hawaii → California
S.Korea + S.Japan → N.Japan → Kamchatka → SW Alaska + Aleutian Islands → Vancouver → California

SE Australia → Victoria Land → Antarctic Peninsula → S.Argentina → N.Brazil + Equador → S.Mexico → Texas + California

Texas → N.Canada → N.Russia → Kazakhstan

***

The spaceports:
Texas, Florida, California, Hawaii, Wake, New England, Newfoundland, Greenland, Iceland, (Good) Old England, W.France, W.Spain, nearly Austria, Somewhere In Poland, Moscow, Kazakhstan, N.Russia, Kamchatka,  N.Canada, SW Alaska, Vancouver,  SW Turkey, Cyprus, Emirates, Pakistan, Kolkatta/Calcutta, S/C.India, Beijing/Shanghai, Thailand, Taiwan, S.Korea, S.Japan, , N.Japan, E.Indonesia, SE Australia, Victoria Land, Antacrtic Peninsula, S.Argentina, N.Brazil, Equador, S.Mexico, probably missed something.

***

So, 28 major and 13 minor (mostly Arctic/Antarctic) launchpads/dropzones.

30..40 objects around the world, requiring several tens of starships to be loaded.

Using every of them once per week for pax and once per month for orbital cargo would mean several hundred thousand tonnes of orbital payload per year.

So, actually this could replace starlink sats with starlink Skylabs.

***

Now true SpaceX fans should must calculate:

a) 1 700 km and 4 000 km suborbital single-stage jumps with passengers
b) 1 700 km path for the reusable first stage.
c) 4 000 km path for the reusable second stage in 3-stage configuration.

Edited June 24, 2020 by kerbiloid

[Xd the great]

15 hours ago, Nightside said:

I'm surprised no one has proposed some sort of zero-g MMA battle. Seems like the sort of bad idea Elon would love.

Spoiler

Do NOT let Elon Musk see it.

 

[Nightside]

5 hours ago, Xd the great said:

  Hide contents

Do NOT let Elon Musk see it.

 

It’s ok, he designs SpaceX on Twitter, not here.

[tater]

 

[RealKerbal3x]

 

[wumpus]

10 hours ago, SOXBLOX said:

Even if orbital tourism did work economically (I think that it does not), it would still not encourage large-scale economic growth in the spaceflight sector. SpaceX loves to do everything in house. Even if it did, it would not be growth in the right way, that is, it would not promote long-term colonization of space. Naturally, I'm assuming this is what you want it to do.I

Also, Disneyworld and Everest do not equal picnics to LEO. 

It's not that I have a problem with orbital tourism, I just see it as an attempt by spaceflight fans to find an economic justification for spaceflight efforts; something of which there is precious little. And don't you dare mention asteroid mining, I've heard all that before!

I'm assuming that most of the space tourism folks look to the expansion of the air industry for examples of progression (and how to pay for what they want to do).

The earliest flyers kept there planes running by barnstorming and taking up passengers for a quick flight.  This looks like the stage we are in.

Mail transport is probably what really got the ball started, but that isn't an option here (although historians are likely to show parallels between early air mail and communication satellites).  Actual passenger airlines took awhile, had to compete with equally glamorous oceanliners, and were rather dangerous (think old Ford Tri-motors).  Presumably Starship could get the price under $10k, but that assumes that  Starship is sufficiently ready to launch and land full of ordinary passengers.  Something has to pay for all those flights until Starship (or New Armstrong or whatever) is ready to carry passengers.

[RealKerbal3x]

Take a look at the LabPadre stream too, Cam2 has a pretty cool wide view:

 

[RealKerbal3x]

SN5 appears to have arrived at the pad!

[sevenperforce]

14 hours ago, StrandedonEarth said:

Zooming waaaaay in... Why yes, it does look like Zeus.

So did they not bolt the test stand down?

Who's to say they didn't?

[tater]

The MECO podcast had an interesting interview about Gateway logistics services. The initial RFP had a max mass of 14 tons because of a 3 year dwell time requirement, and that the PPE had to be able to move the whole stack around.

They are going to dump that in future.

That max mass is why Dragon XL vs a Starship proposal. (pretty funny, really)

[Terwin]

8 hours ago, kerbiloid said:

Now true SpaceX fans should must calculate:

a) 1 700 km and 4 000 km suborbital single-stage jumps with passengers
b) 1 700 km path for the reusable first stage.
c) 4 000 km path for the reusable second stage in 3-stage configuration.

New York, NY to Australia is ~10K miles, and I don't see too many routes that might be notably longer than this.

P2P was supposed to be 30 minutes to anywhere, so one jump.

Many flights will probably need SH, but if SH can get SS to orbit, then with the right orbit(or sub-orbital path), SS can land anywhere it wants with just one jump.

[CatastrophicFailure]

Not one but TWO SpaceX rockets rising on the pads at once.  

 

Ok, ones been risen this whole time, but still...
 

[kerbiloid]

52 minutes ago, Terwin said:

P2P was supposed to be 30 minutes to anywhere, so one jump.

If use an orbital starship, it can't be faster than 45 min to anywhere, because a LEO turn takes 1.5 hours.

[mikegarrison]

We've previously discussed the many complications of commercial point-to-point travel that Elon is either overlooking or downplaying. I'm not sure it's worth going through them yet again.

To me it seems like another "Boring Company" or "Hyperloop". These are ideas that other people have kicked around for a long time, just like reusable retro-propulsive landing rockets. It seems the technology is now right for that last one, as we currently have two companies actually doing it. But that doesn't mean any of the others are going to work out just because that one seems to be moving along.

[cubinator]

15 minutes ago, mikegarrison said:

To me it seems like another "Boring Company" or "Hyperloop". These are ideas that other people have kicked around for a long time, just like reusable retro-propulsive landing rockets. It seems the technology is now right for that last one, as we currently have two companies actually doing it. But that doesn't mean any of the others are going to work out just because that one seems to be moving along.

Quite true. But I do like the fact that there are groups with the resources to "try it anyway! It'll be fun".

[tater]

34 minutes ago, mikegarrison said:

We've previously discussed the many complications of commercial point-to-point travel that Elon is either overlooking or downplaying. I'm not sure it's worth going through them yet again.

To me it seems like another "Boring Company" or "Hyperloop". These are ideas that other people have kicked around for a long time, just like reusable retro-propulsive landing rockets. It seems the technology is now right for that last one, as we currently have two companies actually doing it. But that doesn't mean any of the others are going to work out just because that one seems to be moving along.

Yeah, while I will enjoy watching them try (assuming they do), I'm just not seeing it as a thing. I will be super excited if I'm proved wrong.

FWIW, there are a couple (?) Chinese companies making F9 clones, as well as Arianespace.

^Newline-1

 

^Arianespace

 

[mikegarrison]

To me, the obvious (at least in hindsight) enabling technology for the Falcon 9 and New Shepard et al. is the avionics. The real-time sensing and control required to land a rocket like that simply wasn't available before.

[magnemoe]

1 hour ago, kerbiloid said:

If use an orbital starship, it can't be faster than 45 min to anywhere, because a LEO turn takes 1.5 hours.

Think it can as it can go lower than standard leo since it will only stay an half orbit. 
Downside with many jumps is that refueling eat up a lot of time and require you to land on the launch pad, switching to another starship is even slower with lots of passangers and is pretty stressful. 

However yes an floating starship launch and landing ship is basically an aircraft carrier in its operation. It need to integrate payload, mate starship with superheavy, then fuel this up and launch, then landing of both superheavy and starship. 
It must also be able to do service to them and protect them during bad weather. Then you have fails, worst case as in super heavy just blue screen 100 meter up you are now inside an 5 kiloton fuel air bomb. Note that this is the weight of the bomb not the explosive force. Explosive force would probably be multiple times Hiroshima, your only benefit that this not an nuclear bomb but an chemical explosion lasting couple of seconds so you get something a couple of time worse than the N-1 explosion. 
You can not armor against this. Well if it was an fixed installation like an oil platform you could probably make an shelter below the sea floor but this give the problem of getting out of it if the platform is gone. 

[kerbiloid]

16 minutes ago, magnemoe said:

Think it can as it can go lower than standard leo since it will only stay an half orbit. 

ICBM needs 25..30 min to make a 90..120° flight.

[wumpus]

28 minutes ago, magnemoe said:

Think it can as it can go lower than standard leo since it will only stay an half orbit. 
Downside with many jumps is that refueling eat up a lot of time and require you to land on the launch pad, switching to another starship is even slower with lots of passangers and is pretty stressful.

Earth's radius: 6,380km
Earth's radius+LEO: 6,700km

Half of Earth's circumference: 20,000km
Half of Earth's circumference (at LEO): 21,300km

So going low will save you less than 10% of your distance (10% is less than *sea level*), and require a slightly slower speed.  I'd recommend at least staying out of the atmosphere for the duration.

17 minutes ago, kerbiloid said:

ICBM needs 25..30 min to make a 90..120° flight.

Probably closer to 90 degree, there's no reason to build your ICBMs further south than necessary*.  Also assumes they are for going the quickest route, instead of lofting high and coming down fast (to avoid ABMs).

* Brits threatening Argentina?  That's the biggest cross-hemisphere danger I can think of, and it doesn't seem realistic.

[kerbiloid]

22 minutes ago, wumpus said:

Probably closer to 90 degree, there's no reason to build your ICBMs further south than necessary*

10 000 ... 12 000 ... up to 15 000 km.