Mars and Off Planet Colonization - General Possibilities Discussion

[ecarfan]

I wouldn't send a crew to Mars without the propellants already in place, but that's me.

Neither would I. I think it likely that some of the first uncrewed cargo Starships going to Mars (before any humans make the trip) will contain ISRU technology that will be designed to operate autonomously to test the procedure. If it works, then when the first humans leave for Mars cargo Starships will also leave at the same time with the ISRU equipment.

As to exactly how the O2 and CH4 produced on Mars will be moved from the ships containing the ISRU equipment to the ships that will be making the trip back to Earth I do not know. Maybe they will land ships within 100m of each other and use hoses and pumps? The QD ports are far above ground level so that will require some lifts.

 

[JB47394]

Neither would I. I think it likely that some of the first uncrewed cargo Starships going to Mars (before any humans make the trip) will contain ISRU technology that will be designed to operate autonomously to test the procedure. If it works, then when the first humans leave for Mars cargo Starships will also leave at the same time with the ISRU equipment.

I'd go farther and say that until a Starship can land and fill its tanks with 1200 tons of propellants and keep them topped up, no crew should go to the surface of Mars. ISPP has to be reliably solved at scale.

I can see the row of Starships, each trying to fill their tanks, each one with slightly better technology than the last. When the first crew arrives, they'll find that the one that has full tanks only has them because it was collecting outgassing from the other Starships. But at least they'd be able to get home again.

 

[ecarfan]

I'd go farther and say that until a Starship can land and fill its tanks with 1200 tons of propellants and keep them topped up, no crew should go to the surface of Mars. ISPP has to be reliably solved at scale.

I agree but expect that SpaceX will have no difficulty finding qualified volunteer crew for manned Mars missions even if ISPP has yet to be demonstrated to be 100% reliable.

 

[JB47394]

I agree but expect that SpaceX will have no difficulty finding qualified volunteer crew for manned Mars missions even if ISPP has yet to be demonstrated to be 100% reliable.

Elon loves his drama. Having a crew die on Mars would certainly be dramatic.

 

[Ben W]

Do you have any applications in mind? Dyneema is polymer-impregnated so I assume it cannot easily be broken down to individual strands. How many applications are there for lifting hundreds of tons on Mars over hundreds of meters? Having a cable that can be turned back into individual strands would probably allow it to be used in more applications, despite the lower tensile strength and greater mass.

Dyneema / Zylon is typically sold as a 12-strand braided rope, so presumably it could be un-braided. Or the full 6cm tether could be made by braiding twelve 2cm themselves-braided ropes together. (Or two Starships could be connected via multiple smaller tethers, rather than one large tether.) I don't have a specific use case in mind for Mars, other than that general construction often involves cranes and lifting things using cables. But maybe it's less applicable on Mars because most structures will be underground? Some of the tethers would obviously be re-used for artificial gravity on return crewed journeys, so should be left intact.

 

[JB47394]

Some of the tethers would obviously be re-used for artificial gravity on return crewed journeys, so should be left intact.

Sure, standard crew Starship gear.

Interestingly, this whole discussion assumes that pairs of Starships are traveling together. How about a Starship design where the tether is between cargo and tank sections, allowing a single Starship to rotate by itself? Any plumbing crossing that bulkhead would have to disconnected and later reconnected, and the cargo section would want to flip 180 degrees when tethered. It would take some creativity to make that all work, but it would allow any Starship to spin for gravity, and the involved masses would be low.

 

[Ben W]

Sure, standard crew Starship gear.

Interestingly, this whole discussion assumes that pairs of Starships are traveling together. How about a Starship design where the tether is between cargo and tank sections, allowing a single Starship to rotate by itself? Any plumbing crossing that bulkhead would have to disconnected and later reconnected, and the cargo section would want to flip 180 degrees when tethered. It would take some creativity to make that all work, but it would allow any Starship to spin for gravity, and the involved masses would be low.

"Detach the Saucer Section!" I don't think it's realistic to split Starship in half like this, since (among other things) it would involve splitting the heatshield in half, as well as the downcomers from the header tanks. Sending crewed Starships in pairs has the advantage of avoiding this structural complexity (and corresponding added weight), as well as offering full redundancy in the case of e.g. life-support failure. But a splittable Starship wouldn't be the first time SpaceX has pulled off something "impossible"!

 

[scaesare]

Elon loves his drama. Having a crew die on Mars would certainly be dramatic.

I suspect you had your tongue planted in your cheek when you said this but, based on what we've seen from Elon when it comes to humans thus far, I believe this is the last thing Elon would want, and he'd take it very hard.

 

[JB47394]

I suspect you had your tongue planted in your cheek when you said this

Yep

 

[spacerfc]

I agree but expect that SpaceX will have no difficulty finding qualified volunteer crew for manned Mars missions even if ISPP has yet to be demonstrated to be 100% reliable.

The plan stated publicly a few years ago is that the first crew will be responsible for building the ISRU plant, so there won't be any ISRU plant let alone be 100% reliable before crew arrives. This is not as dangerous as it sounds, since they can keep resupplying the crew if they can't come back, so it's not a death sentence if ISRU didn't produce enough propellent for return in 2 years.

Of course plan is subject to change, and it's been a while since this was mentioned. Also this plan will likely change if it's NASA doing the mission with SpaceX in a partnership instead of SpaceX doing it alone.

 

[Ben W]

The plan stated publicly a few years ago is that the first crew will be responsible for building the ISRU plant, so there won't be any ISRU plant let alone be 100% reliable before crew arrives. This is not as dangerous as it sounds, since they can keep resupplying the crew if they can't come back, so it's not a death sentence if ISRU didn't produce enough propellent for return in 2 years.

Of course plan is subject to change, and it's been a while since this was mentioned. Also this plan will likely change if it's NASA doing the mission with SpaceX in a partnership instead of SpaceX doing it alone.

At the pace at which Optimus (and AI in general) is progressing, I fully expect that the ISRU plant could be built robotically, before humans are sent. Especially with NASA involved on the safety side, and inevitable delays in getting an actual crewed mission sent, this seems like the most likely option to me.

 

[TunaBug]

At the pace at which Optimus (and AI in general) is progressing, I fully expect that the ISRU plant could be built robotically, before humans are sent. Especially with NASA involved on the safety side, and inevitable delays in getting an actual crewed mission sent, this seems like the most likely option to me.

What NASA involvement is there in SpaceX going to Mars? I thought it was entirely a SpaceX thing, meaning that SpaceX will be picking its own astronauts, training them, and defining its own safety protocols as well.

It also remains to be seen what "building" the ISRU plant means. It might be nothing more than running a power cable between the ISRU equipment sent in one starship and the power generator sent in another starship. It's not like there will be people on Mars with milling machines and 3d printers fabricating individual components.

 

[ecarfan]

What NASA involvement is there in SpaceX going to Mars? I thought it was entirely a SpaceX thing, meaning that SpaceX will be picking its own astronauts, training them, and defining its own safety protocols as well.

I hope that NASA is not involved with SpaceX Mars missions because it will slow down the mission timeline in a variety of ways. Yes, Elon is not the best person to be making all the decisions, but he’s not going to live forever. Yes, NASA will require a higher level of safety than Elon will likely prefer. But a lot of NASA’s safety culture has already permeated SpaceX through the Crew Dragon program. Getting the first humans to Mars requires taking a lot of risks. At the rate NASA is going, and the nearly complete lack of Congressional funding, they will never get there. SpaceX has to lead the way.

It also remains to be seen what "building" the ISRU plant means. It might be nothing more than running a power cable between the ISRU equipment sent in one starship and the power generator sent in another starship. It's not like there will be people on Mars with milling machines and 3d printers fabricating individual components.

I would think the ISPP (In Situ Propellant Production) plants will be sent in nearly complete form, with power supplies. But the part that I think will likely require boots on Mars is figuring out how to get the H2O to the plants. It is not readily available nor is it anywhere near pure.

Here is an interesting article Kiloton-Class ISRU Systems for LOX/LCH4 Propellant Production on the Mars Surface

 

[ecarfan]

From Rocket Report: SpaceX’s record year; Firefly’s Alpha rocket falls short

Even with reusability, SpaceX will need to build Starships as often as Boeing builds 737 jetliners in order to realize Elon Musk's ambition for a Mars settlement, Ars reports. "To achieve Mars colonization in roughly three decades, we need ship production to be 100/year, but ideally rising to 300/year," Musk wrote on his social media platform X. SpaceX still aims to make the Starship and its Super Heavy booster rapidly reusable. The crux is that the ship, the part that would travel into orbit, and eventually to the Moon or Mars, won't be reused as often as the booster. These ships will come in a number of different configurations, including crew and cargo transports, refueling ships, fuel depots, and satellite deployers.

When he says “ship production” I assume he means Starship, not Super Heavy.

"The ship needs to complete at least one orbit, but often several to have the ground track line back up with the launch site, so reuse may only be daily," Musk wrote. "This means that ship production needs to be roughly an order of magnitude higher than booster production."

So then booster production is targeted to be 10 to 30/year.

My uneducated guess is that level of production will not be achieved until around 2035.

 

[JB47394]

When he says “ship production” I assume he means Starship, not Super Heavy.

At a guess, they say "ship" and "booster" internally.

So then booster production is targeted to be 10 to 30/year.

You're assuming 10 flights per booster before they're scrapped?

My uneducated guess is that level of production will not be achieved until around 2035.

Starhopper was 2019. If they need to, I think they can scale quickly because that's a solved problem. Civil engineering, employee hiring, supply chains, etc. The problem that I see is having a use for so many ships. To date, the only large scale use of Starships that anyone has talked about is the Mars colony, and I'm not a believer in its value. I'd like to see some other ideas that involve using all that cheap delta-v at the cost of the emissions. Do we really have no use for it?

If SpaceX really goes to Mars, then that will keep Starship moving along and perhaps it will inspire some other ideas (though if there's profit to be made, I suspect Elon would be a first mover). I can easily imagine NASA going for a Moon colony in the same way they pursued the ISS. Perhaps even as an international project. SpaceX could prove out the technology and NASA would just kinda tag along.

 

[ecarfan]

You're assuming 10 flights per booster before they're scrapped?

Oh no; I would not be surprised if SpaceX has an internal target of around 100 flights per booster. Of course some engines, maybe even all, will be replaced during that lifetime.

If SH boosters can fly that many times, maybe they won’t end up producing as many as Elon is estimating.

If SpaceX really goes to Mars

Seriously, I have no doubt that SpaceX will end up sending hundreds of ships to Mars in the next 30 years. Whether that will result in a successful Mars colony remains to be seen…

 

[JB47394]

Water Ice Buried At Mars' Equator Is Over 2 Miles Thick - Slashdot

Keith Cooper reports via Space.com: A European Space Agency (ESA) probe has found enough water to cover Mars in an ocean between 4.9 and 8.9 feet (1.5 and 2.7 meters) deep, buried in the form of dusty ice beneath the planet's equator. The finding was made by ESA's Mars Express mission, a...

science.slashdot.org

"Excitingly, the radar signals match what we expect to see from layered ice and are similar to the signals we see from Mars' polar caps, which we know to be very ice rich," said lead researcher Thomas Watters of the Smithsonian Institution in the United States in an ESA statement. The deposits are thick, extended 3.7km (2.3) miles underground, and topped by a crust of hardened ash and dry dust hundreds of meters thick. The ice is not a pure block but is heavily contaminated by dust. While its presence near the equator is a location more easily accessible to future crewed missions, being buried so deep means that accessing the water-ice would be difficult.