totm nov 2023 SpaceX Discussion Thread

[KSK]

Very much looking forward to seeing this. If there is a viable business plan for ITS then... that would be huge. Really huge.

[magnemoe]

12 minutes ago, Mitchz95 said:

 

First question
Why is the pressurized gas tanks the same size for the far smaller tanks on the upper stage. Its also missing on the first stage upper tank I think. 
 

[kerbinorbiter]

is this red dragon go then? i think it might be

[Scotius]

1 hour ago, Mitchz95 said:

 

Boring Company... IN SPAAAAAAACE!!! Is Elon going to start asteroid mining? Soon we will know

[CatastrophicFailure]

1 hour ago, KSK said:

Very much looking forward to seeing this. If there is a viable business plan for ITS then... that would be huge. Really huge.

Don't you mean...  yuge?

[KSK]

15 minutes ago, CatastrophicFailure said:

Don't you mean...  yuge?

I would actually go as far as to say bigly. Yes - this would indeed be bigly yuge.

[Starman4308]

1 hour ago, KSK said:

Very much looking forward to seeing this. If there is a viable business plan for ITS then... that would be huge. Really huge.

And not just in the size of the booster!

In honesty, I am incredibly skeptical of the ITS, not because I think the physics doesn't work, but because the economics doesn't work; there's just no need for a booster that size unless you're doing something ridiculous like sending men to Mars, and I just don't see that happening, not without an incredibly dramatic reduction in launch costs, beyond what even SpaceX has been able to achieve.

[CatastrophicFailure]

Ahah! They really are going to land it right back on the pad! (No need for legs that way.)

6 hours ago, magnemoe said:

First question
Why is the pressurized gas tanks the same size for the far smaller tanks on the upper stage. Its also missing on the first stage upper tank I think. 
 

IIRC there's no separate pressurant, they'll use methane/oxygen heated in the engine to pressurize the tanks. Maybe the visible tank is just some sort of accumulator?

[Skylon]

Was the raptor test fire a full size version?

I thought their business plan was sorted, with the steal underpants thing. Though, the men's underwear market is expected to be worth $11Bn in 2020, which was his stated cost that the Apollo program was. 

What happens if they loses the rocket on he first launch? I imagine they won't make too many of them, and losing just one might be devastating.

As for other payloads for the ITS, could it launch huge telescopes into orbit? Could they do a preliminary moon mission, and start mining operations there? Could there be use for huge satellites? They could launch space hotels, and then use the crew ship to fly there, though it may be a good idea to adapt it for easier docking, with a nose mounted docking port. The falcon 9 and falcon heavy could launch every ISS module again. 

[tommypops]

59 minutes ago, Skylon said:

They could launch space hotels, and then use the crew ship to fly there, though it may be a good idea to adapt it for easier docking, with a nose mounted docking port. 

I'm thinking it being used as an actual space shuttle, one that's cost effective. Basically what could have been had NASA's shuttles been privately owned. So having them as a crew transporter to LEO would be nice. Maybe impractical, but ehh. 

[TheEpicSquared]

2 hours ago, Skylon said:

Was the raptor test fire a full size version?

I thought their business plan was sorted, with the steal underpants thing. Though, the men's underwear market is expected to be worth $11Bn in 2020, which was his stated cost that the Apollo program was. 

What happens if they loses the rocket on he first launch? I imagine they won't make too many of them, and losing just one might be devastating.

As for other payloads for the ITS, could it launch huge telescopes into orbit? Could they do a preliminary moon mission, and start mining operations there? Could there be use for huge satellites? They could launch space hotels, and then use the crew ship to fly there, though it may be a good idea to adapt it for easier docking, with a nose mounted docking port. The falcon 9 and falcon heavy could launch every ISS module again. 

I think the ITS would be the space hotel.  

[Skylon]

5 minutes ago, TheEpicSquared said:

I think the ITS would be the space hotel.  

Actually, that would make sense. Considering that it is meant to last a journey to mars then there should be no problem with people staying in it

[tater]

 

 

[HebaruSan]

5 hours ago, Skylon said:

Actually, that would make sense. Considering that it is meant to last a journey to mars then there should be no problem with people staying in it

It's an interesting suggestion. If Musk can't find enough people who want to go to Mars in the short term, he can do shorter duration cruises closer to home, like a 100-passenger flyby of the Moon. A flight to the ISS still costs 700 times what Musk's whitepaper says he wants to charge for Mars, so if the ITS works as planned, it should be cost effective on these other flights as well.

[tater]

I think to be worth it as a tourist thing you'd want low lunar orbit. A flyby won't cut it. ITS can do a LLO to LEO return, easily. I'm unsure of what the margins are for propulsive landing on Earth. 

[HebaruSan]

7 minutes ago, tater said:

I think to be worth it as a tourist thing you'd want low lunar orbit. ITS can do a LLO to LEO return, easily. I'm unsure of what the margins are for propulsive landing on Earth. 

Another option is to build two of the ITS passenger craft, put one in lunar orbit stocked for long term testing, fly passengers on the other one, and dock them for elbow room.

7 minutes ago, tater said:

A flyby won't cut it.

Why not? Wasn't that what the previously announced customers were paying far more for on a Dragon?

https://www.theverge.com/2017/2/28/14763632/spacex-private-moon-flight-price-cost-estimate-nasa-space-adventures

[Skylon]

Edit: Please ignore

 

Edited June 18, 2017 by Skylon

[tater]

2 minutes ago, HebaruSan said:

Another option is to build two of the ITS passenger craft, put one in lunar orbit stocked for long term testing, fly passengers on the other one, and dock them for elbow room.

Yeah, this would be a good idea, I suppose. Low lunar orbit is a bad place to leave things, generally, though. Alternately, you use the cargo are for more passengers, or bigger staterooms, or at least thicker walls between the staterooms (I'll leave why as an exercise for the reader), since the vacation might only be a couple weeks.

2 minutes ago, HebaruSan said:

Why not? Wasn't that what the previously announced customers were paying far more for on a Dragon?

https://www.theverge.com/2017/2/28/14763632/spacex-private-moon-flight-price-cost-estimate-nasa-space-adventures

Yeah, because it can happen soon. I'd think in a spacecraft designed for 100+ people to spend 100+ days each way of a trip (and longer on the surface) would offer the possibility of a longer duration flight since the cost of a couple excess weeks is essentially nothing, and lunar orbit would be far more bang for your buck, honestly.

[IncongruousGoat]

1 minute ago, tater said:

Yeah, this would be a good idea, I suppose. Low lunar orbit is a bad place to leave things, generally, though. Alternately, you use the cargo are for more passengers, or bigger staterooms, or at least thicker walls between the staterooms (I'll leave why as an exercise for the reader), since the vacation might only be a couple weeks.

Yeah, because it can happen soon. I'd think in a spacecraft designed for 100+ people to spend 100+ days each way of a trip (and longer on the surface) would offer the possibility of a longer duration flight since the cost of a couple excess weeks is essentially nothing, and lunar orbit would be far more bang for your buck, honestly.

Pity ITS doesn't have enough delta-V to actually land and return on its internal stores. Those people who actually want to colonize the Moon (although the motivation there is beyond me) would jump on a chance for cheap tickets to the surface.

[Skylon]

4 minutes ago, tater said:

Yeah, this would be a good idea, I suppose. Low lunar orbit is a bad place to leave things, generally, though. Alternately, you use the cargo are for more passengers, or bigger staterooms, or at least thicker walls between the staterooms (I'll leave why as an exercise for the reader), since the vacation might only be a couple weeks.

Yeah, because it can happen soon. I'd think in a spacecraft designed for 100+ people to spend 100+ days each way of a trip (and longer on the surface) would offer the possibility of a longer duration flight since the cost of a couple excess weeks is essentially nothing, and lunar orbit would be far more bang for your buck, honestly.

Could a fully fuelled ship land on the Moon?

Also, how many flights of the tanker would it take to refuel the ship just for a Moon flyby/orbit/landing? There would be less cargo if they keep to only 100 people (they could expand this for the shorter journey)

[IncongruousGoat]

1 minute ago, Skylon said:

Could a fully fuelled ship land on the Moon?

Also, how many flights of the tanker would it take to refuel the ship just for a Moon flyby/orbit/landing? There would be less cargo if they keep to only 100 people (they could expand this for the shorter journey)

Land? Probably. Land and return? Probably not. The problem with the Moon is that there's no possibility of any fuel manufacture happening there, ever. There's no carbon, what hydrogen is present is needed for the water the colonists will be drinking, and the rest of the oxygen (that which isn't in the water) is trapped in metal oxides in the regolith.

[Skylon]

4 minutes ago, IncongruousGoat said:

Land? Probably. Land and return? Probably not. The problem with the Moon is that there's no possibility of any fuel manufacture happening there, ever. There's no carbon, what hydrogen is present is needed for the water the colonists will be drinking, and the rest of the oxygen (that which isn't in the water) is trapped in metal oxides in the regolith.

What about with a cargo ITS in orbit for refuelling/extra food and water. The ITS would remain on the surface for only a couple of days in this case

[magnemoe]

1 minute ago, Skylon said:

Could a fully fuelled ship land on the Moon?

Also, how many flights of the tanker would it take to refuel the ship just for a Moon flyby/orbit/landing? There would be less cargo if they keep to only 100 people (they could expand this for the shorter journey)

A fully fueled upper stage can take of from Mars and return to earth.
Mars return is 3800+1440+1060=6300
Moon an back is 3260+680+1732=5672 to land and 1732+680=2412 back

Here assuming free aerobrake and not including landing on earth who would be the dame for both. 
Moon an back will be more expensive. 

Make me wonder if its ice deep down on the Moons around Mars who can be mined. That would be very practical if you do an Mars route. You can fuel up in Mars orbit before landing letting you carry more from Earth, you could even bring water back to LEO for refueling. 

You can also refuel on Moon but only the poles have verified water. 
 

[IncongruousGoat]

Just now, magnemoe said:

You can also refuel on Moon but only the poles have verified water.

Nope. Not the ITS, anyways. You can get water, and therefore hydrogen and oxygen, but there's no source of carbon. In fact, as far as I can tell, there isn't an ounce of usable carbon, elemental or otherwise, on the entire Moon.

[tater]

Yeah, making propellant for ITS on the Moon is highly unlikely, and regardless would take a long time.

I think it nominally has the dv required to land, but not return. Might make it back to LLO, I'm unsure. Any tanker ITS would need to make lunar orbit with enough propellant to give the crew vehicle what it needs to return, and be able to return itself. If it takes 5 tankers to fill ITS, then it reaches LEO with a ~20% margin of props for the ITS. I think it would basically double the refueling flights to land ITS on the Moon. You'd refuel ITS in LEO, then refuel a tanker to some % full, then send that tanker to meet ITS in LLO, then tanker returns, and ITS does its thing. Cargo/supplies are not even an issue, any such trip would be a couple weeks.

Honestly, landers are best as specialized crafts. You'd do better to bring a purpose-built lander that can be reused, and only land a % of the people that have ponied up the cash.

Even a lunar orbital trio would be good bang for the buck. You fly up on ITS. You get a few days worth of LEO while the ITS is loaded with props---that can be spread out as long as needed, and a benefit is that people get sick for a few days typically, so they can do that in LEO, so they are not under the weather near the Moon. Then there is the TLI burn, a few days, and LOI. Spend a few days orbiting the Moon, so that everyone gets awesome views (put a big telescope in the lounge so that people can observe Apollo sites and debunk morons). Then TEI, and direct entry/landing.

On topic for current operations, a pizza delivery guy on reddit (no kidding) delivers to loads of SpaceX employees, and talks to them since he is a space nut. He said a guy working on SLC-40 told him they were gunning for August completion, and had installed the new hold downs. He showed the guy pics on his phone of the wrecked pad from worker level, too.

Edited June 18, 2017 by tater