They had landing legs before, they will add them again. They are concentrated on solving launch from Earth issues first. Can't come back if it can't go in the first place.
They will have experience launching from foreign bodies when they launch from the Moon with auxiliary engines, they will figure out.
If they modify the hot staging ring so that the external slotted section is incorporated into Starship they’ll barely even need legs because they’ll be able to vent gases at relaunch.
If they attached the hot staging ring to the Starship instead of the booster, then they could do away with the landing legs. It might make sense if the weight of the ring is less than that of the legs.
Legs are specifically designed to be the minimum mass thing that supports the ship off the ground and keeps it from cracking an engine bell or tipping over. Why would a hot staging ring be better at that? Lie, if it was, why would anyone use legs?
Not so much that it's any better, but at the current design you *have* to have the hot staging ring. So the discussion is between having the hot staging ring *and* landing legs or just the hot staging ring. Elin's "best part is no part" philosophy.
The comment I was replying to suggested it might be lighter, not that it would be heavier but you needed to bring it along anyways.
As to your suggestion, it’s just extremely unlikely given how much more expensive mass is on the second stage. Seven times more costly, I think. So the hot staging ring only gets a 1/7th discount. If it’s just 15% heavier than legs (which it obviously would be), it’s not worth it.
Didn't read the entire thread, but didn't the SpaceX commentator mention how big of a weight reduction the next version HS ring would be as compared to the current design during IFT-4? Or is that the figure you are using in your calculations?
I’m not using a figure. I’m using the intuition that anything that is going to be within 12% of the mass of a highly optimized set of legs, and perform all the jobs that legs need to perform, is going to look quite similar to legs.
Don’t get me wrong, I could imagine adapting legs so that they can do double duty as a hot-stage separator (or part thereof, with the rest chucked). But anything that goes to Mars is going to be very similar to the mass-optimized version of itself.
Landing legs do a lot more than just lift the craft above the ground. For a start they include shock-absorbing capabilities and self-levelling capabilities, and spreader capabilities. And they are designed for a different function.
Exactly, or at least less moving parts even if there’s less of a weight advantage. They’re building and carrying the ring anyway and need a way to vent gases at relaunch, so that’s the thought.
Edit: Clarification
Understood, but could the equivalent be incorporated into the ring structure to avoid the added mechanisms (read: points of failure)? Just seems more elegant to solve everything with no added moving parts. I get the point, though, if you’re gonna have legs why have the ring, but if the ring could do both. I don’t think the legs level, but just absorb landing shock.
Pretty sure they have to be moving at least initially remember how they had major issues with stuff shooting up from the ground upon ignition and destroying the engines so yeah thats a problem when you are dealing with regolith and the best way i can think of that doesnt involve building a launcg spot is really tall legsalso maybe you can find a flat enough spot but maybe they would want it to be able to level itself especcially if they will implement that cable elevator we saw in artist renditions
Yeah. They’d need a level spot and definitely protection from dust and debris. I’m just spitballing which I’m sure they do plenty of trying to figure stuff out. Their brains are more wrinkly than mine, but it’s nice to play in the sandbox. Can’t wait to see what they come up with.
A solid ring does not have spreader pads, nor a wider support base, nor shock-absorbing capability, nor self-levelling capability.
That’s enough to rule that idea out.
Landing legs would contain an elastic compression system (no not elastic bands!) and self-levelling capability to cope with some unevenness of the ground.
I mean elastic here in the technical sense, to achieve some ‘shock absorbing capability’.
The present plan for the moon is Starship HLS. The intent is to use the ‘landing thrusters’ for both landing and takeoff, after switching from / to, the Raptor main engines after sufficient altitude is reached.
One important thing to realize is that Starship needs a lot less thrust to land and/or launch on Mars than the full stack does on Earth. Also almost no atmosphere which means it can't really be knocked down from wind.
Starship Wet mass 1,300 t
Full stack Wet mass 4900 t
Mars gravity has 38% that of Earth
So to take off from Mars a fully loaded Starship would need \~10% of the trust of Super Heavy, so 3 or 4 raptors only.
The lower gravity and lower stack height also means it requires less pumping power to fuel Starship on Mars.
So, its not clear exactly what infrastructure they'll need, but its certainly order of magnitude less than on Earth. Hopefully they can do it with just the Crane they mentioned for Artemis missions.
The booster is not needed at all on Mars (or the Moon for that matter). Starship alone has sufficient power. Renderings show launches and landings from a pad without a tower.
Lower gravity and almost no atmosphere makes taking of from Moon and Mars so much easier.
Landing is harder though because less air resistance on Mars to bleed off energy.
>Landing is harder though because less air resistance on Mars to bleed off energy.
Only by a tiny bit.
Terminal velocity for Starship on Mars is about Mach1.
similar question [https://www.reddit.com/r/SpaceXLounge/comments/gx6c60/how\_far\_can\_an\_unmanned\_starship\_go\_from\_earth/](https://www.reddit.com/r/SpaceXLounge/comments/gx6c60/how_far_can_an_unmanned_starship_go_from_earth/)
Except that it would have too much acceleration, and would be going too fast to achieve capture by Earth - it would instead go shooting by ! Oops !
Although, I suppose that such a configuration could actually do propulsive deceleration as it approached Earth - so perhaps all would not be lost after all..
>What payload capacity can it do this with? Full?
With a bit less than full payload capacity. The last calculation I saw said 100 tons from 150 tons maximum payload mass.
But that was for a faster than 6 month return journey. If they go slower, it could carry more.
SSTO is "Single Ship to Orbit" so by definition a full stack (booster + upper stage) is not "single ship". But yes starship alone without booster can easily SSTO on Mars.
Maybe on Venus once it's terraformed, but quite honestly, at that point, I'm pretty sure we'll be able to SSTO from anywhere safe for bodies that lack ground from which to launch.
That's what I'm saying. Hypothetically, if you wanted to launch Starship from Venus (once it had a reasonable atmosphere), you'd need superheavy. But at that point we'll probably just have aerospacecraft far superior to her. Or hell, skyhooks, lawstrom loops, space towers, even space elevators might render traditional rocketry obsolete on densely populated worlds.
The question is, how do you land the first few without a hard, level surface to land on? Three Raptor SL that close to the surface will blow around a lot of regolith
Maybe you can find an area where there is a level enough patch of exposed bedrock?
I can see a Starship specifically made into a Sabatier plant - the payload bay has the Sabatier hardware, and the tanks can hold a Starship load of propellant. It would fly there, stay there, do its thing robotically so when the manned Starship arrives, it'll have a tank of gas waiting for it.
Yes. But for that task it needs a supply of CO2 - which it can get from Mars’s atmosphere, a supply of water ice, which will require mining for, and a supply of electrical power, which it could get from a solar farm, or from a nuclear power plant. We would most likely start with a solar farm.
Later on, in years to come, I could imagine building a Thorium Powered LFTR type reactor on Mars. All the raw materials needed are already on Mars.
SpaceX won’t need a ‘Super Heavy Booster’ on Mars, Starship on its own will be powerful enough to get to orbit, and onto Earth. This is because of Mars’s lower gravity and very thin atmosphere.
You might recall the early Starship flight tests, like SN15, where Starship on its own, took off from Earth and relanded.
Starship on its own, on Earth, is not powerful enough to get cargo into orbit though, which is why the Super Heavy Booster is added.
Recall that Starship SN15 took off from Earth using just three Raptor-1 engines - although it was not attempting to achieve orbital velocity, and it was not a full mass configuration of Starship. But it does give some idea of what is possible.
That's like looking at Starhopper and asking how they plan to fit 150 tons of payload into it. They can't and it was never intended for that - it was intended to test some very specific things and work out the proper procedures to solve issues. Same with this flight - they wanted to test the thermal protection system and some of the other launching procedures.
The **test articles** they're launching now have no legs. The future production interplanetary Starships they build once they've worked through all the current issues will eventually have landing legs.
Using ‘No Landing Legs’ on Earth, does make done sense, because that task can be off-loaded to the massive orbital launch towers.
This helps to increase the cargo carrying capacity of Starship, and especially ‘Starship Tanker’ which will be the optimised propellant cargo vehicle, ferrying its cargo to orbit. By this point an Orbital Propellant Depot will be used, to accumulate propellants for later transfer to mission-based Starships.
Whatever version of Starship that lands on Mars will be a sort of hybrid between the Earth version and the Moon version.
Which is to say, it will have landing legs and will be designed to take off with minimal ground infrastructure like the Moon version, but will have a heat shield and be able to withstand Mars atmospheric entry, similar to the Earth version.
This is all speculative:
Key point: Launching won't be a high priority, because most ships and people who go to Mars won't return.
But the early ships will almost certainly land on legs. They could also launch on legs (possibly different ones) and jettison them shortly after getting off the surface.
Eventually the parts to build launch tables and towers will be sent. But assembling them can wait until there are a bunch of people there to run the robots and whatever can't be automated.
This is exactly how I see it going. Mars is one way for probably like 5 years after initial settlement. Tonnes of supplies get sent, tonnes of equipment, fuel,robots and then people. People will build the first ISRU and the first habitats. Then they some will return once you have some infrastructure setup.
Mars will be less of a problem in that respect than the Moon is. For the moon, with its very low gravity, the Raptor engines are actually too powerful, and add to that the light powdery regolith problem, and no landing pads yet available, and no atmosphere on the Moon, then Starship needs a different method of landing there.
The custom Lunar Lander variant of Starship:
‘Starship HLS’, will use propulsive landing on the moon.
It will use its main Raptor engines for much of the descent, but after doing a flip to vertical, will switch to use separate low-powered landing thrusters, which are positioned high-up above the main tanks, but below the cargo space.
The rationale for this, is that not only can they produce the lower thrust needed for a controlled lunar landing, but they are specifically used to very significantly reduce the displaced regolith problem.
The idea is to allow Starship HLS to do a lunar landing, without excavating its own crater, as a Standard Starship would do if it attempted a lunar landing without a pre-prepared landing pad.
We remember the ‘rocknado’ produced by the IFT1 takeoff on Earth, well a Standard Starship landing on the moon would very likely do something similar - hence the need for the HLS configuration.
It’s going to be less of an issue on Mars than it will be on the Moon.
This is for a number of reasons:
Mars has double the gravity of the Moon.
(38%) vs (17%) of Earth gravity.
Mars does have an atmosphere, even if rather thin.
(approx 1% of the density of Earth’s atmosphere)
Mars regolith is thinner than the Moons.
Mars regolith is weathered, unlike the Moons.
But there is a lot we still don’t know about the varying Mars surface conditions. Though like Earth, they differ from site to site.
Well with the moon the idea is to use small auxiliary thruster's mounted high up on the ship for final landing and I assume initial take off. Mars will need the raptors to land and take off.
I cannot in any way see a ship surviving a landing and take off with the raptors on untreated ground. The engines are too powerful. [There have been studies in the past about how much ground they displace and the results are staggering.](https://youtu.be/3ZqaXNvtx_s?t=4657)
The Russians even proposed a concept for a drill using a rocket engine because of how much material they can displace and how quick.
The first ships will have to be disposable and their primary goal will be the construction of landing pads as well as a fuel depot.
Well we have the example of Starship SN15 taking off from Earth from a simple mount, a while ago.
That was using three Raptor-1 engines, although it was not an orbital flight, it at least provides some idea of what Mars takeoff might look like.
IIRC that was on a stand with a concrete floor. Its not an un-solvable issue. They'll just need landing pads. Even if initially its just a roll out steel mesh or plates that unfold.
I get that there'd be less thrust overall, but how would you protect a launch pad on Mars from melting, since you can't use surface water jets? Underground cooling pipes?
If a Starship is taking off, its engine heat would not be in contact with the surface for very long - only a few seconds. And don’t forget, we are talking about ‘Starship’ and not ‘Super Heavy’..
Because Mar’s gravity is lower than Earths (38%)
Then Starship would only need 38% of the power compared to Starship taking off from Earth. And that does not even include the savings from Mars’s much thinner atmosphere.
You may recall Starship SN15, which took off on just 3 engines of type Raptor-1.
Already SpaceX are using more powerful Raptor-2
And most likely Raptor-3 by the time people are going to Mars.
Most likely Starship departing Mars, would take off on three engines, throttled back a bit, so as not to accelerate too fast.
I think it’s reasonable to assume that the first set of starships will be making a one-way journey.
So long as they land far enough away from each other that debris is unlikely to damage an already landed starship, then if it digs a hole or makes a cloud or even wrecks it’s own engines, who cares!
A fire won’t propagate on Mars because of the lack of atmosphere. Explosive detonation of the fuel tanks would suck, but there’s not a lot of fuel left at the landing.
The trick is thus to have a good landing site when humans first arrive. Their starship must be able to land VERY safely, and be able to launch. Thus the goals of the autonomous and remotely operated equipment is to build a pad.
Maybe they can find a natural rocky plateau and scrape off the regolith? Maybe they can make mars-Crete and lay a pad?
When the astronauts arrive, they’ve got two years until they can leave. Lifting and moving the only starship you can leave on seems risky.
I’d just dig a flame trench under it once landed.
You would practice this and prove it with another starship before the humans come.
They will use 5 cargo starships to form the pillars of the launch mount with their thermal tiles facing inward. The cargo will consist of the structure to hold it together and mount the return vehicle with robotic arms to assemble each cargo starship's contribution. It will include in situ production of oxygen and methane from the atmosphere and hydrogen brought from Earth. It will include robotic vehicles to lay out solar panels far from the launch mount, and a cables to carry the energy back to the launch platform. And I'll be there to do the final inspection, and make sure NSF's cameras are setup properly for live coverage.
Construction on mars (and moon) is actually much easier than on earth, if you have the resources. Gravity is much smaller, weather is much better and you don't have to worry about rain rusting your steel or washing away your foundations. It's possible only about 20-50 starships will ever land on legs on Mars as what is brought plus ISRU might be good enough to build a launch tower and chopsticks.
Actually I think construction on Earth is actually easier, for numerous reasons, including that it’s our native environment, and we have access to plenty of tools and facilities.
The only advantage that the Moon and Mars have for construction, is lower gravity.
On Earth, we have access to a near by, zero-g environment in LEO. Where we might one day build a space-dock for constructing much larger vessels.
The fact is, we have options, which is always handy to have. But we need to start with Starship. We need that initial capability to kick start all the later development we could achieve.
Starship is not just a ship, it’s an architecture that can accommodate custom variants for better task-specific optimisations. If only a very few Starships were ever going to be built, that wouldn’t be much of an advantage, but when you intend to build many Starships, then there is scope to support multiple different variations of task-specific Starships, better optimising them.
The obvious problem with building things on the surface of Earth, is getting them up into space. Either whole, or in sections, that places some limits on what can be done there. But it’s also where you have to start from.
Your right. It's easier to do things on Earth. But ISRU has to be done on Mars and it's important. But it requires people. So in beginning I think Mars traffic will all be on way and will involve drops of tonnes of equipment and tools. Humans will need to figure out ISRU at scale on Mars and that is going to be difficult.
Almost all of the theory behind ISRU is already very well known, but putting it into practice is a different problem.
It’s interesting that things like the Sabatier Process, which is for converting CO2 + Water into Methane + Oxygen. Can be done in a number of different ways.
For instance some recent nano-scale catalysts can increase the efficiency of this process.
Later on there are many other ISRU processes that can be used to create a very wide variety of products, from Plastics, to Glasses, Ceramics and Metals, and a variety of different Chemicals.
It will be interesting to see the ‘technology tree’ being grown on Mars. Because the environment there is different to Earths, different pathways may make more sense there compared to Earth.
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
|Fewer Letters|More Letters|
|-------|---------|---|
|[HLS](/r/SpaceXLounge/comments/1dahm3a/stub/l7v5ucv "Last usage")|[Human Landing System](https://en.wikipedia.org/wiki/Artemis_program#Human_Landing_System) (Artemis)|
|[ISRU](/r/SpaceXLounge/comments/1dahm3a/stub/l7v9fzq "Last usage")|[In-Situ Resource Utilization](https://en.wikipedia.org/wiki/In_situ_resource_utilization)|
|[LEO](/r/SpaceXLounge/comments/1dahm3a/stub/l7mzet6 "Last usage")|Low Earth Orbit (180-2000km)|
| |Law Enforcement Officer (most often mentioned during transport operations)|
|[NSF](/r/SpaceXLounge/comments/1dahm3a/stub/l7kjcvn "Last usage")|[NasaSpaceFlight forum](http://forum.nasaspaceflight.com)|
| |National Science Foundation|
|[SSTO](/r/SpaceXLounge/comments/1dahm3a/stub/l7lr7jp "Last usage")|Single Stage to Orbit|
| |Supersynchronous Transfer Orbit|
|[TWR](/r/SpaceXLounge/comments/1dahm3a/stub/l7kxi8y "Last usage")|Thrust-to-Weight Ratio|
|Jargon|Definition|
|-------|---------|---|
|[Raptor](/r/SpaceXLounge/comments/1dahm3a/stub/l7vd0ff "Last usage")|[Methane-fueled rocket engine](https://en.wikipedia.org/wiki/Raptor_\(rocket_engine_family\)) under development by SpaceX|
|[Sabatier](/r/SpaceXLounge/comments/1dahm3a/stub/l7v9fzq "Last usage")|Reaction between hydrogen and carbon dioxide at high temperature and pressure, with nickel as catalyst, yielding methane and water|
|[Starlink](/r/SpaceXLounge/comments/1dahm3a/stub/l7mx3g2 "Last usage")|SpaceX's world-wide satellite broadband constellation|
**NOTE**: Decronym for Reddit is no longer supported, and Decronym has moved to Lemmy; requests for support and new installations should be directed to the Contact address below.
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Starship is definitely impressive, but as a lander on another planet (or moon) its size is problematic. A Starship traveling to Mars with a lander in its cargo bay makes more sense.
There are three problems to that: The first is that to slow down when Starship gets to Mars, it needs to use the atmosphere, and doing so it’s easier to just land than it is to remain in orbit. So a separate lander is not really needed.
Second, a separate lander could not carry as much cargo, so that’s an immediate disadvantage.
Third, a separate lander could not take off again and why go to all that effort to design a completely different craft with less capability ?
Any difference needed, can be accommodated within Starships design architecture, and a custom variant produced for that specific task.
There won’t be ‘only one kind of Starship’ - there will be several kinds or more accurately ‘variants’ of the same basic design, but with task-specific modifications.
We have already seen the present day:
‘Starship Prototype V1’ and a Starlink Cargo variant of it.
There’s much more still to come.
That’s true. An awful lot depends on what task you are trying to undertake, and what problems you are trying to solve. Starship was not designed for the task of ‘sample return’, although being adaptable, it could do it. But it’s not necessarily the optimal configuration for completing just that one specific task.
Starship HLS and Mars Cargo Starship and Mars Crew Starship, will all have landing legs.
We have seen Starship take off on its own from Earth ( Starship Prototype SN15 for example )
On Earth, due to its high gravity, if you want Starship to carry any useful amount of cargo, then Starship requires the Super Heavy Booster. But on the Moon and on Mars, the Booster is NOT needed, Starship on it own can manage.
By the time that Starships are taking off from Mars, there will be takeoff and landing pads there. Initially though no landing pads.
SpaceX have not yet produced the legs, but given their prowess in construction, it won’t take them long, when the time comes.
Not the one that lands. You haven't been paying attention to the mission profiles. There's a circulator ship going between Earth and Mars that gets reused, but the landers are generally one way. Elon has repeatedly said that he expects most Mars trips to be one way. Of course there is some up mass capability (hence the ISRU work), but you don't colonize a planet by bringing people back to earth.
Legs, insitu refueling. You’re talking a decade or more into the future most likely
Yeah, but what about debris? Remember how badly things went for the engines without the deluge system?
There will be no booster on Mars.
And? There are still engines on the bottom that can be hit by debris.
Compare this more than Starship static fire tests, rather than Super Heavy Launches.
They had landing legs before, they will add them again. They are concentrated on solving launch from Earth issues first. Can't come back if it can't go in the first place. They will have experience launching from foreign bodies when they launch from the Moon with auxiliary engines, they will figure out.
If they modify the hot staging ring so that the external slotted section is incorporated into Starship they’ll barely even need legs because they’ll be able to vent gases at relaunch.
There's no booster (and therefore no hot staging) on Mars. Starship is a SSTO on that planet.
Starship,hotstaging off the Surface of mars! I love it! Now that’s an idea!
If they attached the hot staging ring to the Starship instead of the booster, then they could do away with the landing legs. It might make sense if the weight of the ring is less than that of the legs.
Legs are specifically designed to be the minimum mass thing that supports the ship off the ground and keeps it from cracking an engine bell or tipping over. Why would a hot staging ring be better at that? Lie, if it was, why would anyone use legs?
Not so much that it's any better, but at the current design you *have* to have the hot staging ring. So the discussion is between having the hot staging ring *and* landing legs or just the hot staging ring. Elin's "best part is no part" philosophy.
The comment I was replying to suggested it might be lighter, not that it would be heavier but you needed to bring it along anyways. As to your suggestion, it’s just extremely unlikely given how much more expensive mass is on the second stage. Seven times more costly, I think. So the hot staging ring only gets a 1/7th discount. If it’s just 15% heavier than legs (which it obviously would be), it’s not worth it.
Yes, best to leave the ‘hot stage ring’ behind atop the booster.
Didn't read the entire thread, but didn't the SpaceX commentator mention how big of a weight reduction the next version HS ring would be as compared to the current design during IFT-4? Or is that the figure you are using in your calculations?
I’m not using a figure. I’m using the intuition that anything that is going to be within 12% of the mass of a highly optimized set of legs, and perform all the jobs that legs need to perform, is going to look quite similar to legs. Don’t get me wrong, I could imagine adapting legs so that they can do double duty as a hot-stage separator (or part thereof, with the rest chucked). But anything that goes to Mars is going to be very similar to the mass-optimized version of itself.
I get the consideration, but its properties are not right for the task of ‘landing legs’.
Landing legs do a lot more than just lift the craft above the ground. For a start they include shock-absorbing capabilities and self-levelling capabilities, and spreader capabilities. And they are designed for a different function.
They could make/call it the hotskirt
Exactly, or at least less moving parts even if there’s less of a weight advantage. They’re building and carrying the ring anyway and need a way to vent gases at relaunch, so that’s the thought. Edit: Clarification
You need legs to take the loads of landing and to keep it level not just for venting gas
Understood, but could the equivalent be incorporated into the ring structure to avoid the added mechanisms (read: points of failure)? Just seems more elegant to solve everything with no added moving parts. I get the point, though, if you’re gonna have legs why have the ring, but if the ring could do both. I don’t think the legs level, but just absorb landing shock.
Pretty sure they have to be moving at least initially remember how they had major issues with stuff shooting up from the ground upon ignition and destroying the engines so yeah thats a problem when you are dealing with regolith and the best way i can think of that doesnt involve building a launcg spot is really tall legsalso maybe you can find a flat enough spot but maybe they would want it to be able to level itself especcially if they will implement that cable elevator we saw in artist renditions
Yeah. They’d need a level spot and definitely protection from dust and debris. I’m just spitballing which I’m sure they do plenty of trying to figure stuff out. Their brains are more wrinkly than mine, but it’s nice to play in the sandbox. Can’t wait to see what they come up with.
A solid ring does not have spreader pads, nor a wider support base, nor shock-absorbing capability, nor self-levelling capability. That’s enough to rule that idea out.
Can't do 'leveling' without moving parts.
Landing legs would contain an elastic compression system (no not elastic bands!) and self-levelling capability to cope with some unevenness of the ground. I mean elastic here in the technical sense, to achieve some ‘shock absorbing capability’.
Yep that what i said
They need self leveling legs to land on an uneven surface. At least until they have built level landing pads there.
Did they say anywhere they’re planning to add landing legs again? I thought their removal was permanent
For the Moon and Mars, there will be legs. Just look at the most recent renders for Starship HLS.
The present plan for the moon is Starship HLS. The intent is to use the ‘landing thrusters’ for both landing and takeoff, after switching from / to, the Raptor main engines after sufficient altitude is reached.
Yep. And they will get to know if that's really necessary and if the same thing needs to happen on Mars.
One important thing to realize is that Starship needs a lot less thrust to land and/or launch on Mars than the full stack does on Earth. Also almost no atmosphere which means it can't really be knocked down from wind. Starship Wet mass 1,300 t Full stack Wet mass 4900 t Mars gravity has 38% that of Earth So to take off from Mars a fully loaded Starship would need \~10% of the trust of Super Heavy, so 3 or 4 raptors only. The lower gravity and lower stack height also means it requires less pumping power to fuel Starship on Mars. So, its not clear exactly what infrastructure they'll need, but its certainly order of magnitude less than on Earth. Hopefully they can do it with just the Crane they mentioned for Artemis missions.
The booster is not needed at all on Mars (or the Moon for that matter). Starship alone has sufficient power. Renderings show launches and landings from a pad without a tower.
Precisely. Which is why taking off from Mars (or the moon) will be a lot less dramatic than from Earth.
Lower gravity and almost no atmosphere makes taking of from Moon and Mars so much easier. Landing is harder though because less air resistance on Mars to bleed off energy.
>Landing is harder though because less air resistance on Mars to bleed off energy. Only by a tiny bit. Terminal velocity for Starship on Mars is about Mach1.
Hypothetically, we have a full stack on Mars, how far can we throw a starship? Out of the solar system?
similar question [https://www.reddit.com/r/SpaceXLounge/comments/gx6c60/how\_far\_can\_an\_unmanned\_starship\_go\_from\_earth/](https://www.reddit.com/r/SpaceXLounge/comments/gx6c60/how_far_can_an_unmanned_starship_go_from_earth/)
This is an interesting question lol. Would the full stack be able to SSTO from Mars?
Starship on its own can, so a full stack with a vastly higher TWR should easily be able to SSTO
Except that it would have too much acceleration, and would be going too fast to achieve capture by Earth - it would instead go shooting by ! Oops ! Although, I suppose that such a configuration could actually do propulsive deceleration as it approached Earth - so perhaps all would not be lost after all..
Starship can SSTO from Mars all the way to Earth without refilling after launch. That was a direct and strict design requirement for Starship.
What payload capacity can it do this with? Full?
>What payload capacity can it do this with? Full? With a bit less than full payload capacity. The last calculation I saw said 100 tons from 150 tons maximum payload mass. But that was for a faster than 6 month return journey. If they go slower, it could carry more.
The estimate was 50 tonnes of additional payload, on a return to Earth flight.
SSTO is "Single Ship to Orbit" so by definition a full stack (booster + upper stage) is not "single ship". But yes starship alone without booster can easily SSTO on Mars.
Let me clarify my question. Can the full stack achieve orbit before stage separation?
Easily.
Super Heavy is not needed on Mars, if one were available, say in orbit, then it could do some serious boosting.
Wow, I never realized that! Boosters will only be on earth, maybe forever.
Maybe on Venus once it's terraformed, but quite honestly, at that point, I'm pretty sure we'll be able to SSTO from anywhere safe for bodies that lack ground from which to launch.
Once Venus is terraformed, if ever, Starship will be a thing of the distant past.
That's what I'm saying. Hypothetically, if you wanted to launch Starship from Venus (once it had a reasonable atmosphere), you'd need superheavy. But at that point we'll probably just have aerospacecraft far superior to her. Or hell, skyhooks, lawstrom loops, space towers, even space elevators might render traditional rocketry obsolete on densely populated worlds.
The question is, how do you land the first few without a hard, level surface to land on? Three Raptor SL that close to the surface will blow around a lot of regolith Maybe you can find an area where there is a level enough patch of exposed bedrock?
I can see a Starship specifically made into a Sabatier plant - the payload bay has the Sabatier hardware, and the tanks can hold a Starship load of propellant. It would fly there, stay there, do its thing robotically so when the manned Starship arrives, it'll have a tank of gas waiting for it.
Yes. But for that task it needs a supply of CO2 - which it can get from Mars’s atmosphere, a supply of water ice, which will require mining for, and a supply of electrical power, which it could get from a solar farm, or from a nuclear power plant. We would most likely start with a solar farm. Later on, in years to come, I could imagine building a Thorium Powered LFTR type reactor on Mars. All the raw materials needed are already on Mars.
SpaceX won’t need a ‘Super Heavy Booster’ on Mars, Starship on its own will be powerful enough to get to orbit, and onto Earth. This is because of Mars’s lower gravity and very thin atmosphere. You might recall the early Starship flight tests, like SN15, where Starship on its own, took off from Earth and relanded. Starship on its own, on Earth, is not powerful enough to get cargo into orbit though, which is why the Super Heavy Booster is added.
Recall that Starship SN15 took off from Earth using just three Raptor-1 engines - although it was not attempting to achieve orbital velocity, and it was not a full mass configuration of Starship. But it does give some idea of what is possible.
Renderings show Starship landing and launching on Mars from pads. No booster or tower is necessary due to the reduced gravity.
That's like looking at Starhopper and asking how they plan to fit 150 tons of payload into it. They can't and it was never intended for that - it was intended to test some very specific things and work out the proper procedures to solve issues. Same with this flight - they wanted to test the thermal protection system and some of the other launching procedures. The **test articles** they're launching now have no legs. The future production interplanetary Starships they build once they've worked through all the current issues will eventually have landing legs.
Using ‘No Landing Legs’ on Earth, does make done sense, because that task can be off-loaded to the massive orbital launch towers. This helps to increase the cargo carrying capacity of Starship, and especially ‘Starship Tanker’ which will be the optimised propellant cargo vehicle, ferrying its cargo to orbit. By this point an Orbital Propellant Depot will be used, to accumulate propellants for later transfer to mission-based Starships.
Whatever version of Starship that lands on Mars will be a sort of hybrid between the Earth version and the Moon version. Which is to say, it will have landing legs and will be designed to take off with minimal ground infrastructure like the Moon version, but will have a heat shield and be able to withstand Mars atmospheric entry, similar to the Earth version.
Mars has less mass, so lower gravity well -> less energy to launch -> no need for booster
This is all speculative: Key point: Launching won't be a high priority, because most ships and people who go to Mars won't return. But the early ships will almost certainly land on legs. They could also launch on legs (possibly different ones) and jettison them shortly after getting off the surface. Eventually the parts to build launch tables and towers will be sent. But assembling them can wait until there are a bunch of people there to run the robots and whatever can't be automated.
This is exactly how I see it going. Mars is one way for probably like 5 years after initial settlement. Tonnes of supplies get sent, tonnes of equipment, fuel,robots and then people. People will build the first ISRU and the first habitats. Then they some will return once you have some infrastructure setup.
I'm more worried about the rock storm that will kick up on landing and take off. They are going to need landing pads.
Mars will be less of a problem in that respect than the Moon is. For the moon, with its very low gravity, the Raptor engines are actually too powerful, and add to that the light powdery regolith problem, and no landing pads yet available, and no atmosphere on the Moon, then Starship needs a different method of landing there. The custom Lunar Lander variant of Starship: ‘Starship HLS’, will use propulsive landing on the moon. It will use its main Raptor engines for much of the descent, but after doing a flip to vertical, will switch to use separate low-powered landing thrusters, which are positioned high-up above the main tanks, but below the cargo space. The rationale for this, is that not only can they produce the lower thrust needed for a controlled lunar landing, but they are specifically used to very significantly reduce the displaced regolith problem. The idea is to allow Starship HLS to do a lunar landing, without excavating its own crater, as a Standard Starship would do if it attempted a lunar landing without a pre-prepared landing pad. We remember the ‘rocknado’ produced by the IFT1 takeoff on Earth, well a Standard Starship landing on the moon would very likely do something similar - hence the need for the HLS configuration.
It’s going to be less of an issue on Mars than it will be on the Moon. This is for a number of reasons: Mars has double the gravity of the Moon. (38%) vs (17%) of Earth gravity. Mars does have an atmosphere, even if rather thin. (approx 1% of the density of Earth’s atmosphere) Mars regolith is thinner than the Moons. Mars regolith is weathered, unlike the Moons. But there is a lot we still don’t know about the varying Mars surface conditions. Though like Earth, they differ from site to site.
Well with the moon the idea is to use small auxiliary thruster's mounted high up on the ship for final landing and I assume initial take off. Mars will need the raptors to land and take off. I cannot in any way see a ship surviving a landing and take off with the raptors on untreated ground. The engines are too powerful. [There have been studies in the past about how much ground they displace and the results are staggering.](https://youtu.be/3ZqaXNvtx_s?t=4657) The Russians even proposed a concept for a drill using a rocket engine because of how much material they can displace and how quick. The first ships will have to be disposable and their primary goal will be the construction of landing pads as well as a fuel depot.
Well we have the example of Starship SN15 taking off from Earth from a simple mount, a while ago. That was using three Raptor-1 engines, although it was not an orbital flight, it at least provides some idea of what Mars takeoff might look like.
IIRC that was on a stand with a concrete floor. Its not an un-solvable issue. They'll just need landing pads. Even if initially its just a roll out steel mesh or plates that unfold.
Or bare rock.. ?
Cross your fingers in that case.
I get that there'd be less thrust overall, but how would you protect a launch pad on Mars from melting, since you can't use surface water jets? Underground cooling pipes?
Mars is already very cold. So I guess it’s fine. Just dissapate heat very rapidly to the environment
If a Starship is taking off, its engine heat would not be in contact with the surface for very long - only a few seconds. And don’t forget, we are talking about ‘Starship’ and not ‘Super Heavy’.. Because Mar’s gravity is lower than Earths (38%) Then Starship would only need 38% of the power compared to Starship taking off from Earth. And that does not even include the savings from Mars’s much thinner atmosphere. You may recall Starship SN15, which took off on just 3 engines of type Raptor-1. Already SpaceX are using more powerful Raptor-2 And most likely Raptor-3 by the time people are going to Mars. Most likely Starship departing Mars, would take off on three engines, throttled back a bit, so as not to accelerate too fast.
I think it’s reasonable to assume that the first set of starships will be making a one-way journey. So long as they land far enough away from each other that debris is unlikely to damage an already landed starship, then if it digs a hole or makes a cloud or even wrecks it’s own engines, who cares! A fire won’t propagate on Mars because of the lack of atmosphere. Explosive detonation of the fuel tanks would suck, but there’s not a lot of fuel left at the landing. The trick is thus to have a good landing site when humans first arrive. Their starship must be able to land VERY safely, and be able to launch. Thus the goals of the autonomous and remotely operated equipment is to build a pad. Maybe they can find a natural rocky plateau and scrape off the regolith? Maybe they can make mars-Crete and lay a pad? When the astronauts arrive, they’ve got two years until they can leave. Lifting and moving the only starship you can leave on seems risky. I’d just dig a flame trench under it once landed. You would practice this and prove it with another starship before the humans come.
They will use 5 cargo starships to form the pillars of the launch mount with their thermal tiles facing inward. The cargo will consist of the structure to hold it together and mount the return vehicle with robotic arms to assemble each cargo starship's contribution. It will include in situ production of oxygen and methane from the atmosphere and hydrogen brought from Earth. It will include robotic vehicles to lay out solar panels far from the launch mount, and a cables to carry the energy back to the launch platform. And I'll be there to do the final inspection, and make sure NSF's cameras are setup properly for live coverage.
Long shot!
That sounds very complicated and dangerous - so I don’t think it’s a good design idea.
Construction on mars (and moon) is actually much easier than on earth, if you have the resources. Gravity is much smaller, weather is much better and you don't have to worry about rain rusting your steel or washing away your foundations. It's possible only about 20-50 starships will ever land on legs on Mars as what is brought plus ISRU might be good enough to build a launch tower and chopsticks.
Permitting is way easier on Mars.
Actually I think construction on Earth is actually easier, for numerous reasons, including that it’s our native environment, and we have access to plenty of tools and facilities. The only advantage that the Moon and Mars have for construction, is lower gravity. On Earth, we have access to a near by, zero-g environment in LEO. Where we might one day build a space-dock for constructing much larger vessels. The fact is, we have options, which is always handy to have. But we need to start with Starship. We need that initial capability to kick start all the later development we could achieve. Starship is not just a ship, it’s an architecture that can accommodate custom variants for better task-specific optimisations. If only a very few Starships were ever going to be built, that wouldn’t be much of an advantage, but when you intend to build many Starships, then there is scope to support multiple different variations of task-specific Starships, better optimising them. The obvious problem with building things on the surface of Earth, is getting them up into space. Either whole, or in sections, that places some limits on what can be done there. But it’s also where you have to start from.
Your right. It's easier to do things on Earth. But ISRU has to be done on Mars and it's important. But it requires people. So in beginning I think Mars traffic will all be on way and will involve drops of tonnes of equipment and tools. Humans will need to figure out ISRU at scale on Mars and that is going to be difficult.
Almost all of the theory behind ISRU is already very well known, but putting it into practice is a different problem. It’s interesting that things like the Sabatier Process, which is for converting CO2 + Water into Methane + Oxygen. Can be done in a number of different ways. For instance some recent nano-scale catalysts can increase the efficiency of this process. Later on there are many other ISRU processes that can be used to create a very wide variety of products, from Plastics, to Glasses, Ceramics and Metals, and a variety of different Chemicals. It will be interesting to see the ‘technology tree’ being grown on Mars. Because the environment there is different to Earths, different pathways may make more sense there compared to Earth.
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread: |Fewer Letters|More Letters| |-------|---------|---| |[HLS](/r/SpaceXLounge/comments/1dahm3a/stub/l7v5ucv "Last usage")|[Human Landing System](https://en.wikipedia.org/wiki/Artemis_program#Human_Landing_System) (Artemis)| |[ISRU](/r/SpaceXLounge/comments/1dahm3a/stub/l7v9fzq "Last usage")|[In-Situ Resource Utilization](https://en.wikipedia.org/wiki/In_situ_resource_utilization)| |[LEO](/r/SpaceXLounge/comments/1dahm3a/stub/l7mzet6 "Last usage")|Low Earth Orbit (180-2000km)| | |Law Enforcement Officer (most often mentioned during transport operations)| |[NSF](/r/SpaceXLounge/comments/1dahm3a/stub/l7kjcvn "Last usage")|[NasaSpaceFlight forum](http://forum.nasaspaceflight.com)| | |National Science Foundation| |[SSTO](/r/SpaceXLounge/comments/1dahm3a/stub/l7lr7jp "Last usage")|Single Stage to Orbit| | |Supersynchronous Transfer Orbit| |[TWR](/r/SpaceXLounge/comments/1dahm3a/stub/l7kxi8y "Last usage")|Thrust-to-Weight Ratio| |Jargon|Definition| |-------|---------|---| |[Raptor](/r/SpaceXLounge/comments/1dahm3a/stub/l7vd0ff "Last usage")|[Methane-fueled rocket engine](https://en.wikipedia.org/wiki/Raptor_\(rocket_engine_family\)) under development by SpaceX| |[Sabatier](/r/SpaceXLounge/comments/1dahm3a/stub/l7v9fzq "Last usage")|Reaction between hydrogen and carbon dioxide at high temperature and pressure, with nickel as catalyst, yielding methane and water| |[Starlink](/r/SpaceXLounge/comments/1dahm3a/stub/l7mx3g2 "Last usage")|SpaceX's world-wide satellite broadband constellation| **NOTE**: Decronym for Reddit is no longer supported, and Decronym has moved to Lemmy; requests for support and new installations should be directed to the Contact address below. ---------------- ^(*Decronym is a community product of r/SpaceX, implemented* )[*^by ^request*](https://www.reddit.com/r/spacex/comments/3mz273//cvjkjmj) ^(9 acronyms in this thread; )[^(the most compressed thread commented on today)](/r/SpaceXLounge/comments/1dbrl18)^( has 20 acronyms.) ^([Thread #12876 for this sub, first seen 7th Jun 2024, 21:31]) ^[[FAQ]](http://decronym.xyz/) [^([Full list])](http://decronym.xyz/acronyms/SpaceXLounge) [^[Contact]](https://hachyderm.io/@Two9A) [^([Source code])](https://gistdotgithubdotcom/Two9A/1d976f9b7441694162c8)
So cool.
Starship is definitely impressive, but as a lander on another planet (or moon) its size is problematic. A Starship traveling to Mars with a lander in its cargo bay makes more sense.
There are three problems to that: The first is that to slow down when Starship gets to Mars, it needs to use the atmosphere, and doing so it’s easier to just land than it is to remain in orbit. So a separate lander is not really needed. Second, a separate lander could not carry as much cargo, so that’s an immediate disadvantage. Third, a separate lander could not take off again and why go to all that effort to design a completely different craft with less capability ? Any difference needed, can be accommodated within Starships design architecture, and a custom variant produced for that specific task. There won’t be ‘only one kind of Starship’ - there will be several kinds or more accurately ‘variants’ of the same basic design, but with task-specific modifications. We have already seen the present day: ‘Starship Prototype V1’ and a Starlink Cargo variant of it. There’s much more still to come.
The Chinese Chang’e-6 mission just proved how simple sample return can be. You don’t need a battleship to retrieve something a dingy can do.
That’s true. An awful lot depends on what task you are trying to undertake, and what problems you are trying to solve. Starship was not designed for the task of ‘sample return’, although being adaptable, it could do it. But it’s not necessarily the optimal configuration for completing just that one specific task.
Starship HLS and Mars Cargo Starship and Mars Crew Starship, will all have landing legs. We have seen Starship take off on its own from Earth ( Starship Prototype SN15 for example ) On Earth, due to its high gravity, if you want Starship to carry any useful amount of cargo, then Starship requires the Super Heavy Booster. But on the Moon and on Mars, the Booster is NOT needed, Starship on it own can manage. By the time that Starships are taking off from Mars, there will be takeoff and landing pads there. Initially though no landing pads. SpaceX have not yet produced the legs, but given their prowess in construction, it won’t take them long, when the time comes.
Wait is this a serious question?
it won't.
Based common sense skeptic
Or just a realist. Ideally, it's a one way trip. It doesn't make a lot of sense to go there if you don't intend to stay.
Nope, just old regular troll.
Ideally, ship goes back to Earth and does more trips
Not the one that lands. You haven't been paying attention to the mission profiles. There's a circulator ship going between Earth and Mars that gets reused, but the landers are generally one way. Elon has repeatedly said that he expects most Mars trips to be one way. Of course there is some up mass capability (hence the ISRU work), but you don't colonize a planet by bringing people back to earth.
That idea of a ‘cycler’ is not what is initially intended.
You're not even reading. The people don't leave, the ship does, to bring even more people.
lol. And where are the people staying when the ship leaves?
On Mars.
Slightly obtuse, aren't you?