NASASpaceFlight.com Forum
SpaceX Vehicles and Missions => SpaceX Starship Program => Topic started by: Pipcard on 09/08/2022 02:39 am
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The rationale behind an "all-in-one" Mars transportation architecture like Starship is that it is supposed to reduce development costs and that SpaceX can't afford to design and develop multiple, specialized vehicle types.
SpaceX chose the one-vehicle-does-everything (really one base vehicle with multiple variants) because it's easier - particularly in terms of financing. If your constellation and your regular launch customers are launching on your Mars vehicle, you can justify more development money for the Mars vehicle and can build and iterate it faster.
If it turns out that there is an easier way to get to Mars, SpaceX will certainly choose it. I don't see an easier way. Do you? The NASA way of many vehicles each with a special purpose is so expensive that even with 10x or 100x more money than SpaceX they will never make any real progress toward putting a person on Mars.
But every other Mars mission concept has always assumed the launch and assembly of various specialized components: Mars Transfer Vehicles, Mars Ascent Vehicles, Earth Return Vehicles, etc.
I see this discourse on Spaceflight Twitter ("Spitter"), and other spaceflight discussions all the time. So if it's such a sensible idea, why hasn't this been accepted before, and why is it still not accepted by some? Is it about technical risk? The risk of aerocapture? Doubts about the economics of reuse and refueling, or the effectiveness of ISRU? (to be fair, I was also thinking like this six years ago)
https://twitter.com/defconfuck/status/1500229783334100997
https://twitter.com/cowboytragedy/status/1485082240342183937
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The rationale behind an "all-in-one" Mars transportation architecture like Starship is that it is supposed to reduce development costs and that SpaceX can't afford to design and develop multiple, specialized vehicle types.
SpaceX chose the one-vehicle-does-everything (really one base vehicle with multiple variants) because it's easier - particularly in terms of financing. If your constellation and your regular launch customers are launching on your Mars vehicle, you can justify more development money for the Mars vehicle and can build and iterate it faster.
If it turns out that there is an easier way to get to Mars, SpaceX will certainly choose it. I don't see an easier way. Do you? The NASA way of many vehicles each with a special purpose is so expensive that even with 10x or 100x more money than SpaceX they will never make any real progress toward putting a person on Mars.
But every other Mars mission concept has always assumed the launch and assembly of various specialized components: Mars Transfer Vehicles, Mars Ascent Vehicles, etc.
Remember though, the assumption before Elon Musk and SpaceX was that reusable launchers were impractical, and reusable spaceships that can land on Earth AND Mars were impossible.
I see this discourse on Spaceflight Twitter ("Spitter"), and other spaceflight discussions all the time. So why hasn't this been accepted before, and why is it still not accepted? Is it about technical risk? The risk of aerocapture? Doubts about the economics of reuse and refueling, or the effectiveness of ISRU? (to be fair, I was also thinking like this six years ago)
Until now no one thought that one vehicle could take off from Earth, transit to Mars, land on Mars, and then take off again, transit to Earth, and then land back on Earth. That is a LOT of transportation segments to do with one vehicle, but that is what the Starship transportation system is planned to be able to do.
Add on top of that the amount of cargo that it can carry while doing all of that, and it becomes clear that this approach could drive down the cost of getting humans and cargo to Mars by simplifying the transportation system.
However SpaceX has not proved it can do all of those transportation segments, but the reasoning for trying seems sound.
As venture capitalist John Doerr is famous for saying:
Ideas are easy. Execution is everything. It takes a team to win.
So another way to answer your question is that until now (or recently), SpaceX hadn't shown the world it was possible to use one reusable vehicle for a Mars transportation architecture.
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Because all the previous Mars architecture were thought up by governments, they don't care about cost, and they can't easily sell the excess launches/services due to various reasons (laws preventing government from competing with private companies, unable to expand market using something like Starlink, turf war between different parts of the government i.e. NASA vs DoD, etc)
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Because SpaceX saw that ISRU propellant could be used to fill a single-stage methalox vehicle capable of getting from the Martian surface to Mars orbit. Once you believe that, most of the remaining aspects of the original "MCT" re-usability architecture fall into place.
Of course it also helps if you have an iron-clad belief that lifting commodity propellant to LEO is going to be super-cheap.
Underlying that is the observation Musk made in 2019 that it would take around one million tons of cargo to build a self-sustaining settlement on Mars. No one else cared about that, because no one else thought making life multi-planetary was the goal of Mars missions, or at least that it could be anywhere on the planning horizon.
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Because previous missions were for small scale exploration, while SpaceX’s goal is mass colonization.
So flight numbers are orders of magnitude higher, hence the need for uniformity and economies of scale.
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It is no question, that from a technical perspective, you could build vehicles better suited for a certain part of the mars mission. But the one important thing that is missing in his analysis is dollar.
SpaceShip will allow to transport 150t of mass to mars for good money. And in the end, if you are serious about colonizing mars, that is the only metric interesting.
I admit, I would really love to see a nuclear cycler, grabbing 10 SpaceShips and move them to mars, but while I really like the idea, this stops the moment I think about short term costs. If we had some governments supporting this idea and adding maybe 30 Billion to development, well maybe. Until than ...
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In principle, I agree with the posters you've quoted - that Starship will eventually be best used as an atmospheric launch/landing craft at Earth/Mars, and for interplanetary cargo transport.
The problem as I see it is that inert cargo is fine over interplanetary transit timeframes because it doesn't need much power and doesn't generate much heat, but the large, space-optimised solar arrays and thermal rejection systems required for long-duration human spaceflight will take up way too much space on Starships that will spend the majority of each mission on the ground at Mars. Remember that Starship hasn't even tried to address the solar power/thermal problems yet, and the animations that depict these massive (but still way too small) solar arrays folding up neatly into tiny parts of Starship's cargo bay aren't believable as yet.
What you could have as well as Starship, would be a Starship-derived and constructed interplanetary vehicle that uses Methalox/Raptor propulsion and can use the Starship refuelling infrastructure, but can take a much greater number of people at a time due to extra power and heat management capacity, and provides significant comfort/safety improvements over and above Starship, like spin-gravity and better radiation protection. I'm imagining something like the baton structure depicted in the Vast company materials. You could imagine these travelling with the fleet when it goes - say one crewed ship for every ten cargo Starships. People would split up and transfer to the starships only in the days before EDL at Mars, then refuel it and take it with them when they return to Earth.
The key sticking point is that in order for it to be reusable, you need it to be able to do aerocapture at the end of each transit, and I don't know enough about how much heat shielding is required for something of those dimensions to brake into orbit.
EDIT: It just occurred to me that, as long as the crew transfer to the Starships and do a direct entry, the interplanetary vessel could spend the best part of an Earth-Mars synodic period aerobraking into low Mars orbit in preparation for the return journey. So maybe the heat-shielding for aerobraking doesn't need to be all that robust - just the bare minimum to get into high Mars orbit.
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It is no question, that from a technical perspective, you could build vehicles better suited for a certain part of the mars mission. But the one important thing that is missing in his analysis is dollar.
SpaceShip will allow to transport 150t of mass to mars for good money. And in the end, if you are serious about colonizing mars, that is the only metric interesting.
I admit, I would really love to see a nuclear cycler, grabbing 10 SpaceShips and move them to mars, but while I really like the idea, this stops the moment I thing about short term costs. If we had some governments supporting this idea and adding maybe 30 Billion to development, well maybe. Until than ...
Forgive my ignorance. How does a cycler collect the 10 Starships in Earth orbit? Does the cycler slow down or do the Starships speed up to match the cycler’s velocity? If the latter, zero fuel is saved compared to the Starship flying to Mars independently.
And since the Starships still need to atmospherically brake and propulsively land on Mars, no heat shield or landing fuel mass is saved either.
So what is the benefit of using a nuclear cycler for the middle part of the journey?
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Because SpaceX saw that ISRU propellant could be used to fill a single-stage methalox vehicle capable of getting from the Martian surface to Mars orbit. Once you believe that, most of the remaining aspects of the original "MCT" re-usability architecture fall into place.
Of course it also helps if you have an iron-clad belief that lifting commodity propellant to LEO is going to be super-cheap.
Underlying that is the observation Musk made in 2019 that it would take around one million tons of cargo to build a self-sustaining settlement on Mars. No one else cared about that, because no one else thought making life multi-planetary was the goal of Mars missions, or at least that it could be anywhere on the planning horizon.
Mars Direct had the same realization re: an ISRU-propelled return vehicle yet didn’t follow the all-in-one architecture. Heck, Zubrin continues to rail against landing a full Starship on Mars. What Musk and SpaceX realized is that a fully-reusable vehicle reduces how aggressively you need to play the mass-optimization game.
That realization, plus the desire to mass-produce these vehicles, opened them up to interesting tradeoffs – like stainless steel.
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As soon as you are doing aerocapture you need a proper heat shield. Peak temperature occurs before peak acceleration so the temperatures will be similar to direct entry (although duration is shorter).
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The only company to step up with a Mars program is SpaceX - there is no other alternative design (only those on paper) and SpaceX is going with something that suits their needs both in LEO and for Mars. So a one design platform tweaked to work for all situations fits their business and engineering needs. If mars was the only destination and they were spending someone’s else’s money then then design might have been different. Their design reflects their commercial needs elsewhere but is till a fantastic design for mars.
Nothing stopping others from spending their $$$ and building their own platforms based on their architecture tradeoffs but I have my doubts we will see much of anything.
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In principle, I agree with the posters you've quoted - that Starship will eventually be best used as an atmospheric launch/landing craft at Earth/Mars, and for interplanetary cargo transport.
The problem as I see it is that inert cargo is fine over interplanetary transit timeframes because it doesn't need much power and doesn't generate much heat, but the large, space-optimised solar arrays and thermal rejection systems required for long-duration human spaceflight will take up way too much space on Starships that will spend the majority of each mission on the ground at Mars. Remember that Starship hasn't even tried to address the solar power/thermal problems yet, and the animations that depict these massive (but still way too small) solar arrays folding up neatly into tiny parts of Starship's cargo bay aren't believable as yet.
What you could have as well as Starship, would be a Starship-derived and constructed interplanetary vehicle that uses Methalox/Raptor propulsion and can use the Starship refuelling infrastructure, but can take a much greater number of people at a time due to extra power and heat management capacity, and provides significant comfort/safety improvements over and above Starship, like spin-gravity and better radiation protection. I'm imagining something like the baton structure depicted in the Vast company materials. You could imagine these travelling with the fleet when it goes - say one crewed ship for every ten cargo Starships. People would split up and transfer to the starships only in the days before EDL at Mars, then refuel it and take it with them when they return to Earth.
The key sticking point is that in order for it to be reusable, you need it to be able to do aerocapture at the end of each transit, and I don't know enough about how much heat shielding is required for something of those dimensions to brake into orbit.
EDIT: It just occurred to me that, as long as the crew transfer to the Starships and do a direct entry, the interplanetary vessel could spend the best part of an Earth-Mars synodic period aerobraking into low Mars orbit in preparation for the return journey. So maybe the heat-shielding for aerobraking doesn't need to be all that robust - just the bare minimum to get into high Mars orbit.
Just realised this specialisation of functions helps another way too. If your starship fleet travels with an interplanetary transfer-only vessel that aerobrakes into orbit and doesn't have to land, it means that the fleet has one ship that doesn't have any propellant to keep cold either. Being in the sun constantly, with big solar arrays, means it can cast a shadow over the other vessels in the fleet, meaning much less work to keep the propellant cold in the Starships which do have to land. In this scenario, since your crew is in the transfer vessel, you wouldn't even need to keep the temperature in the landing Starship crew cabins all that warm, just warm enough not to damage anything in storage.
So to take this a bit further, let's imagine this interplanetary transfer vessel is - for simplicity's sake - a standard-sized Starship - but instead of the smaller "Elonerons" and a full complement of heat shield tiles of the standard Starship, it has much larger, inflatable "Elonerons" that - during launch - are held tightly on either side of the ship. Once the TMI burn has been performed, the Elonerons inflate to butterfly-like proportions relative to the rest of the ship, with a heat shielding surface on one side (a la LOFTID (https://www.nasa.gov/feature/inflatable-heat-shield-one-step-closer-to-2022-demonstration)), and the solar arrays on the other. The transfer ship is then ready to take on crew, to commence spin-G for the cruise phase, whilst also casting a shadow over the rest of the fleet.
Days or weeks prior to EDL at Mars, the spin is stopped and the crew transfers back to the landing Starships and prepare for landing. The transfer Starship leaves the Elonerons out to perform the aerobrake maneuver, but takes a much higher path through the Mars atmosphere, just enough to brake into a highly elliptical orbit.
As a side note: this scenario would make it easier to specialise this transfer Starship for spin gravity, because unlike previous debates around tail to tail spin gravity, this craft would never be used "the right way up" on Mars, so crew quarters would be designed for nose-down operations.
As soon as you are doing aerocapture you need a proper heat shield. Peak temperature occurs before peak acceleration so the temperatures will be similar to direct entry (although duration is shorter).
Okay. But heating is proportional to the density of atmosphere you're moving through right? So the bigger your surface area (e.g. inflatable Elonerons) the higher you can pass through in the atmosphere, so lower overall heating sustained for equivalent delta V, yes?
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It is no question, that from a technical perspective, you could build vehicles better suited for a certain part of the mars mission. But the one important thing that is missing in his analysis is dollar.
SpaceShip will allow to transport 150t of mass to mars for good money. And in the end, if you are serious about colonizing mars, that is the only metric interesting.
I admit, I would really love to see a nuclear cycler, grabbing 10 SpaceShips and move them to mars, but while I really like the idea, this stops the moment I thing about short term costs. If we had some governments supporting this idea and adding maybe 30 Billion to development, well maybe. Until than ...
Forgive my ignorance. How does a cycler collect the 10 Starships in Earth orbit? Does the cycler slow down or do the Starships speed up to match the cycler’s velocity? If the latter, zero fuel is saved compared to the Starship flying to Mars independently.
And since the Starships still need to atmospherically brake and propulsively land on Mars, no heat shield or landing fuel mass is saved either.
So what is the benefit of using a nuclear cycler for the middle part of the journey?
The typical idea is that vehicles will speed up to match the cycler. The advantage is that the vehicles can then be designed to be lightweight (relative to the cycler) or conversely, the cycler can be very very massive; not needing to worry about spending propellant at each arrival/departure. This also provides a very large volume for the comfort of the crew during the long voyage, and transfer vehicles do not waste power and consumables - as these are provided by the cycler.
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Of course it also helps if you have an iron-clad belief that lifting commodity propellant to LEO is going to be super-cheap.
Starship critics/skeptics expect it to cost something like $100 million a launch, or that launch cadence will not be rapid, or that it can be cheap but that cryogenic propellant transfer won't be practical. That is why they may view "the need to refuel multiple times to leave LEO" as a disadvantage and advocate for high-energy third stages and dedicated MTV assembly.
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Why hasn't there been an "all-in-one" (same vehicle) Mars architecture before?
Here's why
Elon:
The extreme difficulty of scaling production of new technology is not well understood. It's 1000% to 10,000% harder than making a few prototypes. The machine that makes the machine is vastly harder than the machine itself.
Creating a custom Mars looper, a Mars Gateway, a Mars Lander that could handle the volume needed for colonization would be three times harder than creating one machine that produces variants of a single proven implementation.
There are only a few system engineers at Elon's level capable of architecting the machine that builds the machine, So it probably wouldn't even happen if the task was three times harder.
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Why hasn't there been an "all-in-one" (same vehicle) Mars architecture before?
Here's why
Elon:
The extreme difficulty of scaling production of new technology is not well understood. It's 1000% to 10,000% harder than making a few prototypes. The machine that makes the machine is vastly harder than the machine itself.
Creating a custom Mars looper, a Mars Gateway, a Mars Lander that could handle the volume needed for colonization would be three times harder than creating one machine that produces variants of a single proven implementation.
There are only a few system engineers at Elon's level capable of architecting the machine that builds the machine, So it probably wouldn't even happen if the task was three times harder.
There are many, many brilliant system architects that can do this. The problem is that there are no projects of this complexity that are under control of a single top-level system architect, except SpaceX. That's because the funding level required for these projects is so high that the project must be subdivided at the political level and parceled out to separate organizations without a top-level architecture being finalized by a competent system architect. The best the resulting pool of system architects can do then is negotiate among themselves to create proper formal interfaces among the top-level subsystems, and this process is intensely political as it affects the separate responsibilities and interests of the various stakeholders instead of being focused on the best top-level architecture.
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Why hasn't there been an "all-in-one" (same vehicle) Mars architecture before?
Here's why
Elon:
The extreme difficulty of scaling production of new technology is not well understood. It's 1000% to 10,000% harder than making a few prototypes. The machine that makes the machine is vastly harder than the machine itself.
Creating a custom Mars looper, a Mars Gateway, a Mars Lander that could handle the volume needed for colonization would be three times harder than creating one machine that produces variants of a single proven implementation.
There are only a few system engineers at Elon's level capable of architecting the machine that builds the machine, So it probably wouldn't even happen if the task was three times harder.
There are many, many brilliant system architects that can do this. The problem is that there are no projects of this complexity that are under control of a single top-level system architect, except SpaceX. That's because the funding level required for these projects is so high that the project must be subdivided at the political level and parceled out to separate organizations without a top-level architecture being finalized by a competent system architect. The best the resulting pool of system architects can do then is negotiate among themselves to create proper formal interfaces among the top-level subsystems, and this process is intensely political as it affects the separate responsibilities and interests of the various stakeholders instead of being focused on the best top-level architecture.
You are more optimistic about system architects than I am. I am a system architect, and very humbled by Elon's ability, and have rarely met a system architect who amazes me.
But yes, the system architect having the money to do the project also puts him in charge, instead of the politicians and the program managers. And that is what it takes, and that combo is what is extremely rare. Now go find three of those, each with their own shareholder profit motives that have to be satisfied.
Will never happen.
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Of course it also helps if you have an iron-clad belief that lifting commodity propellant to LEO is going to be super-cheap.
Starship critics/skeptics expect it to cost something like $100 million a launch, or that launch cadence will not be rapid, or that it can be cheap but that cryogenic propellant transfer won't be practical. That is why they may view "the need to refuel multiple times to leave LEO" as a disadvantage and advocate for high-energy third stages and dedicated MTV assembly.
And to be fair to the skeptics/critics, the very low cost and high cadence probably requires rapid, cheap (low refurbishment) tanker reuse, ie not like Shuttle TPS etc. That's kind of undemonstrated.
I mean I doubt it's going to be 100 million a launch even with expendable tankers, but maybe 50 million or something.
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Why hasn't there been an "all-in-one" (same vehicle) Mars architecture before?
Here's why
Elon:
The extreme difficulty of scaling production of new technology is not well understood. It's 1000% to 10,000% harder than making a few prototypes. The machine that makes the machine is vastly harder than the machine itself.
Creating a custom Mars looper, a Mars Gateway, a Mars Lander that could handle the volume needed for colonization would be three times harder than creating one machine that produces variants of a single proven implementation.
There are only a few system engineers at Elon's level capable of architecting the machine that builds the machine, So it probably wouldn't even happen if the task was three times harder.
There are many, many brilliant system architects that can do this. The problem is that there are no projects of this complexity that are under control of a single top-level system architect, except SpaceX. That's because the funding level required for these projects is so high that the project must be subdivided at the political level and parceled out to separate organizations without a top-level architecture being finalized by a competent system architect. The best the resulting pool of system architects can do then is negotiate among themselves to create proper formal interfaces among the top-level subsystems, and this process is intensely political as it affects the separate responsibilities and interests of the various stakeholders instead of being focused on the best top-level architecture.
You are more optimistic about system architects than I am. I am a system architect, and very humbled by Elon's ability, and have rarely met a system architect who amazes me.
But yes, the system architect having the money to do the project also puts him in charge, instead of the politicians and the program managers. And that is what it takes, and that combo is what is extremely rare. Now go find three of those, each with their own shareholder profit motives that have to be satisfied.
Will never happen.
If Elon needed to accomplish a task that took thrice the resources, he would start by accumulating the resources. But more likely he would start by finding a cheaper way to do the task, or find an achievable task. His self-selected task is to colonize Mars. his approach appears to be feasible, but is far cheaper than any other realistic approach that I have seen. It also helps to work on a problem in a simple domain that you can truly understand. He's not trying to solve world hunger, world peace, etc. He did take a shot at global warming with Tesla, but it's beyond the reach of a single self-funded system architect.
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Of course it also helps if you have an iron-clad belief that lifting commodity propellant to LEO is going to be super-cheap.
Starship critics/skeptics expect it to cost something like $100 million a launch, or that launch cadence will not be rapid, or that it can be cheap but that cryogenic propellant transfer won't be practical. That is why they may view "the need to refuel multiple times to leave LEO" as a disadvantage and advocate for high-energy third stages and dedicated MTV assembly.
Refueling when it comes to Mars is a non-issue
. The reason NASA preferred MTV is because the wanted an Apollo like Approach and thought that going into Mars Orbit and not direct landing was the safest way to Mars. Mars pretty much demands refueling if you are going to do it via MTV and single launch architectures with high energy third stages are expensive and limited.
NASA's plans tended to be build a MTV big enough to hold everything the crew would need for a 2 year mission to Mars and back. The lander may use ISRU or be carried with the MTV or another MTV sent ahead.
By going into orbit you take some risk out such as bad weather at landing site and you don't need to land 2 years of supplies at once.
Elon can't go this way. There is no commercial use for a MTV or expendable three stage high energy rockets. This would be too costly for him. He needs to go another way.
With Starship you could preposition supplies on the surface and he is willing to take the risk of needing ISRU to get the crew back. Most importantly Starship must have commercial uses or else it will be too expensive for Elon.
NASA is not in the business of launching anything other than manned missions and something like starship wouldn't be attractive.
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NASA is not in the business of launching anything other than manned missions and something like starship wouldn't be attractive.
They launch all kinds of unmanned probes.
If by launch you mean using their own rockets, that still overlooks Saturn V-Skylab and Ares V which was to be cargo only.
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NASA is not in the business of launching anything other than manned missions and something like starship wouldn't be attractive.
They launch all kinds of unmanned probes.
If by launch you mean using their own rockets, that still overlooks Saturn V-Skylab and Ares V which was to be cargo only.
No they don't launch probes that was done mostly by commercial. The Shuttle did launch probes a long time ago but that was because the Shuttle was to replace all other launchers and the commercialization of space had not happened yet. After Challenger U.S. Space policy did a 180 and the Shuttle more or less was restricted from carrying things that could be launched by other rockets.
In the time of Saturn V there was no commercial option. In the time of Ares V, other non Shuttle derived rockets could have been chosen for upgrade into a HLV and they would likely be more economical than Ares V and Ares 1 was a total waste of money as commercial rockets could have sent both cargo and crew to the ISS. Heck you could possible get Orion or something a tad lighter to a gateway in two launches of an 25+MT rocket with simple docking.
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There's never been a Mars DRM calling for orbital cryogenic propellant transfer, either. That's the root of why no all-in-one vehicles.
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There's never been a Mars DRM calling for orbital cryogenic propellant transfer, either. That's the root of why no all-in-one vehicles.
Right. Folks had suggested that SSTO RLVs like Delta Clipper could do it, but not many detailed DRMs.
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Because all the previous Mars architecture were thought up by governments, they don't care about cost, and they can't easily sell the excess launches/services due to various reasons (laws preventing government from competing with private companies, unable to expand market using something like Starlink, turf war between different parts of the government i.e. NASA vs DoD, etc)
This is really silly. As if the reasons where political, when they are technical.
And, by the way... http://www.astronautix.com/p/projectdeimos.html
I have to say, aside from the above example, I can't think of many other Mars architectures indeed, where a RLV, SSTO or TSTO would be a) refueled in LEO and b) used as a "universal vehicle" up to Mars surface.
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Even Zubrin's liquid CO2 NTR SSTO hopper for mars wouldn't be really usable elsewhere.
Well, unless it was somehow docking to some kind of external generator/radiator system to run as a NEP core (think a bimodal NTR where you can selectively release the power generator/radiator complex). But even that won't help for earth SSTO LEO.
Even if the NTR core chamber/nozzle setup could be swapped/fiddled with to change between an impulse rocket and feeding a brayton turbine for shaft power, I don't think even John Bucknell's NTTR fanket design (which appears to be one of the few earth NTR SSTO designs), running on liquid CO2 instead of LH2, can escape earth...
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There is one thing called Oberth effect, which, simply put, means that in planet with a deep gravity well, high thrust maneuver at the bottom of the well is much more efficient than low thrust high above the well.
https://en.wikipedia.org/wiki/Oberth_effect
There is another thing called aero capture, which states that a EDL capable ship can break into low orbit from interplanetary trajectory for free.
https://en.m.wikipedia.org/wiki/Aerocapture
This results in Starship can use almost a magnitude of order less delta-v than SEP when traveling between LEO and LMO. Similarly, for traveling between two body with decent atmosphere, a chemical, high thrust, EDL capable spacecraft is no less efficient than so called “specified vehicle” with less structural mass and high Isp.
This is the same philosophy as in Mars Direct, and the only difference is the sheer vehicle size. Which is why Dr.Zubrin oppose the original ITS with a smaller ITS, rather than some “specific vehicle”.
Landing on body without atmosphere doesn’t require EDL capability, but still require high thrust propulsion, so the propulsion section can still be shared, which is exactly what Starship HLS does.
It’s amazing that 6 years after the initial ITS presentation, there are still people like the two twitter users OP quoted thinking that starship is just an LEO optimized vehicle.
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NASA is not in the business of launching anything other than manned missions and something like starship wouldn't be attractive.
They launch all kinds of unmanned probes.
If by launch you mean using their own rockets, that still overlooks Saturn V-Skylab and Ares V which was to be cargo only.
No they don't launch probes that was done mostly by commercial. The Shuttle did launch probes a long time ago but that was because the Shuttle was to replace all other launchers and the commercialization of space had not happened yet. After Challenger U.S. Space policy did a 180 and the Shuttle more or less was restricted from carrying things that could be launched by other rockets.
In the time of Saturn V there was no commercial option. In the time of Ares V, other non Shuttle derived rockets could have been chosen for upgrade into a HLV and they would likely be more economical than Ares V and Ares 1 was a total waste of money as commercial rockets could have sent both cargo and crew to the ISS. Heck you could possible get Orion or something a tad lighter to a gateway in two launches of an 25+MT rocket with simple docking.
You are using all kinds of semantics and rationalization, but you are in denial about reality.
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Concerning specialized craft, I am in the camp that starship is "good enough" for initial general purpose missions, but that as the archetecture scales up, massive cyclers are a natural extension.
It's worth looking at cyclers as "point to point" class destinations- PTP starship is intended to carry thousands for very short lengths of time, whereas a mars craft can only carry a few score for the months it takes to reach mars. With a cycler, starship can fly in the PTP configuration, and offload the passengers to the cycler, then reload and land at the destination.
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It's probably been covered, but these specialist elements per phase of the mission miss something fundamental - business and finance.
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Creating a custom Mars looper, a Mars Gateway, a Mars Lander that could handle the volume needed for colonization would be three times harder than creating one machine that produces variants of a single proven implementation.
Absolutely this.
The scale of Elon’s ambition is staggering, to get 1,000,000 people, supplies, equipment etc to Mars. Hundreds/thousands of Starships and tens of thousands of flights. High volume production is a key driver and few people understand the implications of that better than Elon.
Remember too that he’s in a hurry. He worries there may be a small window in which to achieve a self-sustaining Mars civilisation. So he goes all in with the first viable approach that stands a chance of being affordable. Starship has to help pay for itself, such as Earth point-to-point transportation, or whatever SpaceX can find a large market for.
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If we assume, purely for the sake of argument, that someone comes up with a viable and cost effective alternative for the Earth/Mars coast phase (cycler or whatever), how would the Earth Launch/EDL and Mars Launch/EDL ship designs change?
Obviously the Mars ships wouldn't ever need a booster, or to refuel in orbit. They wouldn't need engines optimised for Earth sea level pressure either, but you'd presumably need to gimbal at least some of the RVacs. What else?
Maybe the fact that no single vehicle operates on both planets makes planetary protection simpler?
Would the Earth ships change much at all?
How much would these changes impact the vehicle cost and/or performance?
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They would need a lot more dv to return as the standard cycler idea is that the small "shuttles" go along with the cycler and does EDL at the destination.
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This is not an issue of generalist vs. specialist. The "all in one" just does not work without the cheap, reusable and high capacity architecture of Starship. In turn, this architecture with the expedited powered landings was not possible much earlier, without the current high capacity computers.
Sending an large interplanetary spacecraft to Mars FUELED (equivalent of the proposed direct architecture for Apollo) would be extraordinarily difficult and expensive. If propellant is produced in situ, then either the production capacity remains limited, or we need to send hundreds of tons of equipment. By this reason Mars Direct proposed an extremely small Earth Return Vehicle, too small for serving also, as surface hab. As this was seen unrealistic later, i was replaced with an in-situ fueled Mars Ascent Vehicle just for reaching an fueled orbiting return vehicle in the Semi-Direct version.
We need the 100+ ton capacity and cheap Starship to build a surface infrastructure that can refill a Starship.
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Because all the previous Mars architecture were thought up by governments, they don't care about cost, and they can't easily sell the excess launches/services due to various reasons (laws preventing government from competing with private companies, unable to expand market using something like Starlink, turf war between different parts of the government i.e. NASA vs DoD, etc)
This is really silly. As if the reasons where political, when they are technical.
And, by the way... http://www.astronautix.com/p/projectdeimos.html
I have to say, aside from the above example, I can't think of many other Mars architectures indeed, where a RLV, SSTO or TSTO would be a) refueled in LEO and b) used as a "universal vehicle" up to Mars surface.
I can. ;)
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Because all the previous Mars architecture were thought up by governments, they don't care about cost, and they can't easily sell the excess launches/services due to various reasons (laws preventing government from competing with private companies, unable to expand market using something like Starlink, turf war between different parts of the government i.e. NASA vs DoD, etc)
This is really silly. As if the reasons where political, when they are technical.
And, by the way... http://www.astronautix.com/p/projectdeimos.html
I have to say, aside from the above example, I can't think of many other Mars architectures indeed, where a RLV, SSTO or TSTO would be a) refueled in LEO and b) used as a "universal vehicle" up to Mars surface.
I can. ;)
Wait wait, the PPT in the paper isn't a Phoenix E though...
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Because all the previous Mars architecture were thought up by governments, they don't care about cost, and they can't easily sell the excess launches/services due to various reasons (laws preventing government from competing with private companies, unable to expand market using something like Starlink, turf war between different parts of the government i.e. NASA vs DoD, etc)
This is really silly. As if the reasons where political, when they are technical.
The reasons *are* political, for example the reason NASA is interested in SEP/NTP in Mars mission is because they want to minimize IMLEO, and why do they want to minimize IMLEO? Because they had to use SLS which is expensive and has low cadence and couldn't put up much IMLEO. That's how politics forces NASA to pick an optimization that is not optimal at all if you start from first principles.
SpaceX on the other hand is optimizing for lowest possible $/kg to surface of Mars, given current law of physics and engineering, that's how they arrived at Starship.
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Because all the previous Mars architecture were thought up by governments, they don't care about cost, and they can't easily sell the excess launches/services due to various reasons (laws preventing government from competing with private companies, unable to expand market using something like Starlink, turf war between different parts of the government i.e. NASA vs DoD, etc)
This is really silly. As if the reasons where political, when they are technical.
When taxpayer money is involved, then of course decisions about which architectures to use is political. Especially when there are companies that want that taxpayer money.
And as we have seen with the SLS program, Boeing is not motivated to build the least expensive way to move mass to space. If anything they have viewed the SLS program as a way to squeeze out the maximum amount of revenue - regardless of our national needs.
Large government contractors like Boeing would never propose a system that significantly lowers the cost of moving mass to/thru space, since that makes no financial sense to them. Remember they are focused on shareholder value, and only in extreme national emergencies would they propose something that endangers that.
Unfortunately colonizing Mars is not an extreme national emergency, so Boeing, Lockheed Martin, Northrop Grumman, and other large government contractors are not really motivated to solve the problem of colonizing Mars, as it hasn't been in their risk-averse nature to try and solve that problem.
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Because all the previous Mars architecture were thought up by governments, they don't care about cost, and they can't easily sell the excess launches/services due to various reasons (laws preventing government from competing with private companies, unable to expand market using something like Starlink, turf war between different parts of the government i.e. NASA vs DoD, etc)
This is really silly. As if the reasons where political, when they are technical.
And, by the way... http://www.astronautix.com/p/projectdeimos.html
I have to say, aside from the above example, I can't think of many other Mars architectures indeed, where a RLV, SSTO or TSTO would be a) refueled in LEO and b) used as a "universal vehicle" up to Mars surface.
I can. ;)
Wait wait, the PPT in the paper isn't a Phoenix E though...
Picky, picky. :) It could have been. There is a rather complicated backstory why it was proposed (trying to get a partner to join the effort). My preference was to use the tanker version of Phoenix.
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I think the reason is "they haven't done the math".
As soyuzu above said
1. Oberth
2. No fuel to land because of heat shield
These 2 alone reduces the delta-V and therefore the fuel budget to get to mars surface.
On the other hand I would like to go to mars. Maybe die there. But I would like 1g sleeping and eating and pooping. S agree with mikelepage's post that the interplanetary segment could be done with spinning gravity and better radiation shielding. Where that extra stuff(gravity and rad prot) goes is not clear. Or a high priority at first.
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I would like to go to mars. Maybe die there. But I would like 1g.
Travelers to Mars might prefer 0.375g (Mars gravity equivalent) on the outbound voyage. Has SpaceX ever hinted at a configuration like Phoenix-E, with two ships connected nose-to-nose by a deployed boom?
EDIT: Added image from Hudson's paper linked above.
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I would like to go to mars. Maybe die there. But I would like 1g.
Travelers to Mars might prefer 0.375g (Mars gravity equivalent) on the outbound voyage. Has SpaceX ever hinted at a configuration like Phoenix-E, with two ships connected nose-to-nose by a deployed boom?
EDIT: Added image from Hudson's paper linked above.
I don't remember that exact configuration, but Elon has expressed interest in artificial gravity on more than one occasion.
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So if it's such a sensible idea, why hasn't this been accepted before, and why is it still not accepted by some? Is it about technical risk? The risk of aerocapture? Doubts about the economics of reuse and refueling, or the effectiveness of ISRU? (to be fair, I was also thinking like this six years ago)
It only works at scale. Not just vehicle scale (though it does require a large vehicle, both the launch vehicle and the landed component on Mars) but scale of the programme.
Starship's Mars architecture assumes a super-heavy-lift vehicle operating at a steady pace, and it assumes you will be able to emplace either ISRU equipment or at least return propellants in a manner that lets you load propellants onto your return vehicle. That means it needs lots of launches. For a commercial programme, that's a feature not a bug: more launches means fixed costs are spread over more launches, which means per-launch costs trend downwards.
But previous Mars architectures have not been commercial. That means more launches is an absolute cost increase due to the launch vehicle not being used for anything else. Even historic attempts to do so (e.g. Apollo Applications) were squashed, and since 1998 the Commercial Space Act has prohibited that commercial use explicitly. As a confounding factor, use of propellant depots and prop transfer were also active quashed for some time due to an influential senator.
That means architectures that use fewer launches are preferred over those that use more. Less overall upmass means vehicles needs to be more mass efficient, and dedicated purpose vehicles and split-vehicle architecture (don't drop your entire vehicle to the surface and drag it out of the gravity well again, just drop as small a shuttle as possible, to save on overall propellant usage) are more mass efficient than multiple generic vehicles.
But another confounding factor is the need for a Mars programme and Mars architecture to be the same thing. That seems like something that is obvious, but is something that is not the case with Starship. To wit: the Starship development programme is well underway and closing on on first orbital launch whilst technology vital to that architecture is not even on the drawing board (e.g. ISRU propellant production). That sort of run before you can walk behaviour has been unthinkable for previous programmes, because they were constrained to a "fund programme, get Mars landing" budget model. All technological development needed for the end goal needed to be bundled in under the overall programme, and needed to be completed before any launches could even think about occurring. That overall budget limit also optimises for limited missions (one or a handful of short visits) over longer term plans. That means optimising the vehicles for that particular architecture gains you more than using suboptimal 'generic' vehicles that will not be used for anything else (and certainly not anything else under that particular programme).
tl;dr Funding mechanism impacts programme architecture, programme architecture impacts vehicle architecture. Large generic vehicles are suboptimal for architectures that assume Mars landings achieved within a single programme.
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No, it doesn’t require super heavy lift scale to work. It would work just fine anything from 10 tons to 50 tons as well. Just need smaller crew sizes. It’s a good concept that saves money by minimizing the non-recurring engineering cost.
…which is part of the reason NASA didn’t pick something like it. It’s not a ZIP Code engineering friendly approach. NASA has a whole bunch of centers that need to have work spread to, so having one vehicle that can do almost all the roles is problematic for them. The space station people don’t like it because it doesn’t need a space station, nor does it need a Mars Transfer Vehicle derived from Station concepts, nor does it need hundreds of days spent in orbit each way. The in-space power and propulsion folk might not like it because it doesn’t need advanced nuclear thermal or solar/nuclear-electric propulsion. The advanced reentry folk might not like it because it doesn’t need a separate inflatable heatshield, just the heatshield that the RLV already needs for the SSTO/upper-stage. The Utah delegation isn’t going to like it because it doesn’t have any use for large SRBs. Etc, etc.
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IMHO only a small fraction of possible architectures have been explored. There are plenty of novel designs still to come. There are plenty of novel designs that will never be explored.
No, I cannot give examples, ask me again in 50 years.
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I would like to go to mars. Maybe die there. But I would like 1g.
Travelers to Mars might prefer 0.375g (Mars gravity equivalent) on the outbound voyage. Has SpaceX ever hinted at a configuration like Phoenix-E, with two ships connected nose-to-nose by a deployed boom?
EDIT: Added image from Hudson's paper linked above.
Many moons ago I proposed a very similar cycler architecture: https://forum.nasaspaceflight.com/index.php?topic=50250.msg2051490#msg2051490
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There hasn't "been" any other HSF Mars architectures... only powerpoint vehicles. There are a lot of reasons for that, and this thread discusses a lot of them. But the overarching reason is that everything until now has been theoretical, and proving theory requires building reality.
Also, space Twitter seems to have a very low signal to noise ratio, so I wouldn't consider the acceptance of some theory there as particularly meaningful.
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If Elon needed to accomplish a task that took thrice the resources, he would start by accumulating the resources. But more likely he would start by finding a cheaper way to do the task, or find an achievable task. His self-selected task is to colonize Mars. his approach appears to be feasible, but is far cheaper than any other realistic approach that I have seen. It also helps to work on a problem in a simple domain that you can truly understand. He's not trying to solve world hunger, world peace, etc. He did take a shot at global warming with Tesla, but it's beyond the reach of a single self-funded system architect.
In each case I think his approach is what Nicholas Taleb called “AntiFragile”. It has a distant very abstract goal and adapts on the way to take advantage of chaos.
Settling Mars is itself a Subgoal on the path to making humanity genuinely spacefaring and multi planetary which is itself a Subgoal of increasing the probability of the long term survival of civilization.
Solving world hunger or world peace are actually smaller subsidiary goals along the path that at some point are achieved as a side effect.
An example of this is the pivot to Optimus humanoid robots by Tesla. This wasn’t part of Musk’s plan when he was first investing in Tesla or SpaceX it’s an opportunity to shift that occurred along the way that suits the most distant goals. A drop in replacement for most human labor that can be mass produced like a self driving vehicle seemed possible with the solution to machine vision Tesla was already achieving. Mass producing it would help with all the other projects - and likely pay it’s own way.
Incidentally, a mass produced humanoid robot would happen to solve poverty and hunger too. It seems likely that Optimus robots will be on the moon and Mars from the beginning and make the Spacefaring goals much more attainable - but Humanoid robots weren’t part of the plan from the beginning.
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The rationale behind an "all-in-one" Mars transportation architecture like Starship is that it is supposed to reduce development costs and that SpaceX can't afford to design and develop multiple, specialized vehicle types.
SpaceX chose the one-vehicle-does-everything (really one base vehicle with multiple variants) because it's easier - particularly in terms of financing. If your constellation and your regular launch customers are launching on your Mars vehicle, you can justify more development money for the Mars vehicle and can build and iterate it faster.
If it turns out that there is an easier way to get to Mars, SpaceX will certainly choose it. I don't see an easier way. Do you? The NASA way of many vehicles each with a special purpose is so expensive that even with 10x or 100x more money than SpaceX they will never make any real progress toward putting a person on Mars.
But every other Mars mission concept has always assumed the launch and assembly of various specialized components: Mars Transfer Vehicles, Mars Ascent Vehicles, Earth Return Vehicles, etc.
I see this discourse on Spaceflight Twitter ("Spitter"), and other spaceflight discussions all the time. So if it's such a sensible idea, why hasn't this been accepted before, and why is it still not accepted by some? Is it about technical risk? The risk of aerocapture? Doubts about the economics of reuse and refueling, or the effectiveness of ISRU? (to be fair, I was also thinking like this six years ago)
https://twitter.com/defconfuck/status/1500229783334100997
https://twitter.com/cowboytragedy/status/1485082240342183937
I agree with you, the Starship system itself is an ideal, at the moment, shuttle "Earth Surface - Orbit". Starship acquires the properties of an interplanetary ship only after refueling to LEO.
Why Musk made such a decision was explained to you from all sides. That's right, Musk does it because he can.
I'll try to explain by analogy. At first, the Polynesians used logs and rafts as watercraft. This is the level of rocket science until about 2015. And this level did not suit the Musk. Then the Polynesians began to hollow out logs, and the first boat turned out. This is an analogue of the Falcon-9 with a reusable first stage. But Musk wants to swim across to the neighboring island, which is visible on the horizon. But the boat made of logs is unstable and constantly capsizes. And someone came up with the idea of tying a log-balancer to the boat. The result was a catamaran, on which the Polynesians settled many oceanic islands.
So Musk creates a system that is minimally suitable for the beginning of the colonization of Mars. I do not believe that the process of creating an autonomous Martian Colony will take only twenty years, but it will be possible to start colonization using a Starship fueled in LEO. Musk is in a hurry, and the development of events shows us that he is in a hurry for good reason, and cruise ships will appear much later.
But there are two more aspects of events that have not been taken into account here. The first is that now SpaceX has become a real forge of personnel for a variety of industries. And not only personnel, but also new methods of work. In addition, it must be taken into account that with the start of regular Starship flights, space will become much more accessible. And for the slowly ongoing work on the creation of a thermonuclear rocket engine, a real customer will appear. But there are such projects, and some of them have not been implemented so far just because no one needs these engines now. When Starship is flying regularly and the creation of the Martian Colony begins, the situation will change dramatically, and Musk's next project may be an interplanetary orbital-based ship with thermonuclear engines. And Starship will be used as a surface-to-orbit shuttle.
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But there are two more aspects of events that have not been taken into account here. The first is that now SpaceX has become a real forge of personnel for a variety of industries. And not only personnel, but also new methods of work. In addition, it must be taken into account that with the start of regular Starship flights, space will become much more accessible. And for the slowly ongoing work on the creation of a thermonuclear rocket engine, a real customer will appear. But there are such projects, and some of them have not been implemented so far just because no one needs these engines now. When Starship is flying regularly and the creation of the Martian Colony begins, the situation will change dramatically, and Musk's next project may be an interplanetary orbital-based ship with thermonuclear engines. And Starship will be used as a surface-to-orbit shuttle.
Great explanation for why Elon is on the path he is, but you have to realize the advantages of refueling in LEO.
First, it's how airplanes have done it for 70+ years. They use to have "mothership" craft prototypes (including dirigibles) but all those ideas died in favor or refueling.
A "mothership" craft designed for space can't aerobrake. That throws away 1.5km/sec of deltaV at Mars.
Second, impulse burns get you there faster. The VASMIR proposal gets to Mars slower than a Starship, and VASMIR is fully of fantasy power and cooling elements that haven't been built. Its only advantages is less tonnage to LEO (about half that of Starship), which, with cheap flights to LEO, isn't an advantage worth anything.
To get an impulse burn (or at least a 1 day burn) out of a 2000Isp system you need insane power densities.
Let's calculate those using a 2000 Isp (minimum needed to overcome lack of aerobraking and show some sort of clear advantage). Let's say 20km/sec exhaust V. And 6km/sec of deltaV to make the transit slightly faster to Mars.
That's a net 6 + 2 + 1.5 = 9.5km/sec of deltaV. (the 2 is to brake at Mars from a faster-than-Hohmann orbit)
At an acceleration of 9,500/86400 = 0.11 m/s2.
say the craft can carry cargo 1,000t. if you can't handle 10 starships worth of cargo why bother? The starships are mass produced and cheap. let's call the non-cargo mass 200T, and that requires using the rocket equation to get 778t of fuel or 1978t starting mass.
That requires a force of 218kN, and a mass flow rate of 218kN/20km/s2 or 11kg/sec.
the energy rate for that is 2.2GW. Input would be about 4.4GW with a 50% efficiency, and that's 2.2GW of cooling panels... which would take up the entire mass of spacecraft at 1kg/kw. Ooops.
A radiative or active cooling system is a non-starter. Any such thermonuclear engine would have to act like the chemical engines and exhaust 100% of the waste heat with the rocket exhaust.
A thermal energy of 2.2GW applied to 5.5kg of say Argon (520J/kg-K) would heat that Argon up to an insane 384,000K. Plasma temperatures. No material can get anywhere near that without turning into plasma as well, and per Stefan Boltzmann that material will be emitting all of its energy in the form EM radiation very very quickly. Probably in the xray spectrum, but too lazy to count that right now. Faster than you can exhaust it out the back too, in about 4-5mm of travel at that exhaust velocity. That radiation will melt anything it touches given the small area the 11kg/sec is exiting the rocket.
IOTW, energy density problem. I could if inclined make a close-form solution that describes energy density in terms of Isp and deltaV, or anyone with college-level physics could do it. Too lazy to do it today.
I haven't even counted radiation shielding needed for fusion. I don't think anyone has figured out how to direct neutrons out the back. You could try boron-born aneutronic fusion and direct all those alpha particles out the back with superconducting magnetics. Maybe.
TL;DR there's no physically plausible system that can create, contain, and direct a few kg of plasma in the single-digit GW range needed for a thermonuclear engine to get to Mars.
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First of all, thanks for the excellent reasoned answer
Great explanation for why Elon is on the path he is, but you have to realize the advantages of refueling in LEO.
First, it's how airplanes have done it for 70+ years. They use to have "mothership" craft prototypes (including dirigibles) but all those ideas died in favor or refueling.
A "mothership" craft designed for space can't aerobrake. That throws away 1.5km/sec of deltaV at Mars.
An orbital-based ship, you have designated it as a "mothership", is not intended at all to land on large planets, Earth, Mars, and even the Moon. If he arrives on Mars, he should be met by Starships - shuttles that flew there earlier. In principle, this ship can carry Starships with it, but in the presence of a Martian Colony, this usually does not make sense.
Second, impulse burns get you there faster. The VASMIR proposal gets to Mars slower than a Starship, and VASMIR is fully of fantasy power and cooling elements that haven't been built. Its only advantages is less tonnage to LEO (about half that of Starship), which, with cheap flights to LEO, isn't an advantage worth anything.
VASMIR is not discussed here.
To get an impulse burn (or at least a 1 day burn) out of a 2000Isp system you need insane power densities.
An unrealistically small ISP value for a fusion engine.
Let's calculate those using a 2000 Isp (minimum needed to overcome lack of aerobraking and show some sort of clear advantage). Let's say 20km/sec exhaust V. And 6km/sec of deltaV to make the transit slightly faster to Mars.
That's a net 6 + 2 + 1.5 = 9.5km/sec of deltaV. (the 2 is to brake at Mars from a faster-than-Hohmann orbit)
At an acceleration of 9,500/86400 = 0.11 m/s2.
I absolutely agree, but, unfortunately, neither I nor anyone else TODAY has the necessary information for calculations. However, I will try to find the alleged data. I'm not quite ready for a deep argument right now. These questions are discussed in this thread:
https://forum.nasaspaceflight.com/index.php?topic=5367.0
say the craft can carry cargo 1,000t. if you can't handle 10 starships worth of cargo why bother? The starships are mass produced and cheap. let's call the non-cargo mass 200T, and that requires using the rocket equation to get 778t of fuel or 1978t starting mass.
I assume that, as a rule, an orbital-based ship should carry cargo, but not starships. However, sometimes these will be Starships, with complex equipment installed on Earth. Such Starships after landing can be used as production facilities.
For example, 10,000 tons of cargo, or cargo lifted from Earth by a hundred Starships.
That requires a force of 218kN, and a mass flow rate of 218kN/20km/s2 or 11kg/sec.
the energy rate for that is 2.2GW. Input would be about 4.4GW with a 50% efficiency, and that's 2.2GW of cooling panels... which would take up the entire mass of spacecraft at 1kg/kw. Ooops.
A radiative or active cooling system is a non-starter. Any such thermonuclear engine would have to act like the chemical engines and exhaust 100% of the waste heat with the rocket exhaust.
Absolutely agree.
A thermal energy of 2.2GW applied to 5.5kg of say Argon (520J/kg-K) would heat that Argon up to an insane 384,000K. Plasma temperatures. No material can get anywhere near that without turning into plasma as well, and per Stefan Boltzmann that material will be emitting all of its energy in the form EM radiation very very quickly. Probably in the xray spectrum, but too lazy to count that right now. Faster than you can exhaust it out the back too, in about 4-5mm of travel at that exhaust velocity. That radiation will melt anything it touches given the small area the 11kg/sec is exiting the rocket.
Unrealistically low temperature for thermonuclear fusion. Of course, only the magnetic nozzle.
IOTW, energy density problem. I could if inclined make a close-form solution that describes energy density in terms of Isp and deltaV, or anyone with college-level physics could do it. Too lazy to do it today.
I haven't even counted radiation shielding needed for fusion. I don't think anyone has figured out how to direct neutrons out the back. You could try boron-born aneutronic fusion and direct all those alpha particles out the back with superconducting magnetics. Maybe.
Unfortunately, I don't do it. I'm just a fan here.
TL;DR there's no physically plausible system that can create, contain, and direct a few kg of plasma in the single-digit GW range needed for a thermonuclear engine to get to Mars.
I will try to find available information and we can continue the dispute in a couple of days in this thread:
https://forum.nasaspaceflight.com/index.php?topic=5367.0
I agree with you - THERE ARE NO SUCH ENGINES TODAY. But this does not mean that they will not appear after some time.
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I will try to find available information and we can continue the dispute in a couple of days in this thread:
https://forum.nasaspaceflight.com/index.php?topic=5367.0
183 pages. Yikes. Which one of those pages has someone doing the math?
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I will try to find available information and we can continue the dispute in a couple of days in this thread:
https://forum.nasaspaceflight.com/index.php?topic=5367.0
183 pages. Yikes. Which one of those pages has someone doing the math?
Ah, this is how you got from here to there :-)
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Ludus: "Incidentally, a mass produced humanoid robot would happen to solve poverty and hunger too."
I think I'm going to be sick. Can we stick to reality?
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The rationale behind an "all-in-one" Mars transportation architecture like Starship is that it is supposed to reduce development costs and that SpaceX can't afford to design and develop multiple, specialized vehicle types.
SpaceX chose the one-vehicle-does-everything (really one base vehicle with multiple variants) because it's easier - particularly in terms of financing. If your constellation and your regular launch customers are launching on your Mars vehicle, you can justify more development money for the Mars vehicle and can build and iterate it faster.
If it turns out that there is an easier way to get to Mars, SpaceX will certainly choose it. I don't see an easier way. Do you? The NASA way of many vehicles each with a special purpose is so expensive that even with 10x or 100x more money than SpaceX they will never make any real progress toward putting a person on Mars.
But every other Mars mission concept has always assumed the launch and assembly of various specialized components: Mars Transfer Vehicles, Mars Ascent Vehicles, Earth Return Vehicles, etc.
I see this discourse on Spaceflight Twitter ("Spitter"), and other spaceflight discussions all the time. So if it's such a sensible idea, why hasn't this been accepted before, and why is it still not accepted by some? Is it about technical risk? The risk of aerocapture? Doubts about the economics of reuse and refueling, or the effectiveness of ISRU? (to be fair, I was also thinking like this six years ago)
There was an all in one rocket. Way before the compromises of the space program and the identification of operational problems, the nuclear powered rocket provided the required transportation system. It's the most sensible idea, it's just been very difficult to put into practice.
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Space exploration will solve food problems as food will have to be grown on Mars to sustain a colony. What they learn will be applied to earth.
The all in one idea is the only practical idea that can work today. It is like a pickup truck. You can use it around town (LEO), to carry and pick up supplies. You can put a camper on it and go long distances by refueling along the way. Or you can carry cargo or supplies long distance by refueling along the way. A pickup truck can move you across country with minimum household needs (Mars), by pulling a trailer. Starship is like a large diesel pickup vs a small short bed truck (F9).
Anything else, will require development like nuclear powered spacecraft, SEP powered spacecraft, large ion engines, large mother ships. This would require NASA and other developers.
SpaceX has Tesla for electric vehicles for Mars, as well as solar panels for power. Musk's brother is doing container gardening which may be used to grow food on Mars. The Boring company can drill underground habitats on Mars and maybe even Hyperloop tunnels to connect areas to avoid dust above ground. Starship will work until larger vehicles are built for transport.
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I will try to find available information and we can continue the dispute in a couple of days in this thread:
https://forum.nasaspaceflight.com/index.php?topic=5367.0
183 pages. Yikes. Which one of those pages has someone doing the math?
Many people do math. But you need to have initial data, such as the efficiency of a fusion engine, in order to calculate the required area and mass of radiators, the mass of radiation protection, and other basic parameters of an orbital-based interplanetary spacecraft.
The power and thrust of a fusion engine can be relatively small if its resource exceeds the flight time.
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There was an all in one rocket. Way before the compromises of the space program and the identification of operational problems, the nuclear powered rocket provided the required transportation system. It's the most sensible idea, it's just been very difficult to put into practice.
Unfortunately no. A thermal nuclear engine (NTR engine) does not provide enough thrust to launch from the surface of the Earth, so a booster will be required. In addition, NTR provides a strong radioactive contamination of a large launch region due to the removal of irradiated nuclear fuel through the nozzle. Therefore, NTR can only be launched after reaching orbits of at least 800 km.
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There was an all in one rocket. Way before the compromises of the space program and the identification of operational problems, the nuclear powered rocket provided the required transportation system. It's the most sensible idea, it's just been very difficult to put into practice.
Unfortunately no. A thermal nuclear engine (NTR engine) does not provide enough thrust to launch from the surface of the Earth, so a booster will be required. In addition, NTR provides a strong radioactive contamination of a large launch region due to the removal of irradiated nuclear fuel through the nozzle. Therefore, NTR can only be launched after reaching orbits of at least 800 km.
And once you figure out how to refuel fully reusable rockets, the NTR becomes obsolete, since its only savings is mass to LEO, which is about to get 1000x cheaper.
Which answers the OP,
Why hasn't there been an "all-in-one" (same vehicle) Mars architecture before?
"Because nobody could figure out how to make mass to LEO cheap".
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There was an all in one rocket. Way before the compromises of the space program and the identification of operational problems, the nuclear powered rocket provided the required transportation system. It's the most sensible idea, it's just been very difficult to put into practice.
Unfortunately no. A thermal nuclear engine (NTR engine) does not provide enough thrust to launch from the surface of the Earth, so a booster will be required. In addition, NTR provides a strong radioactive contamination of a large launch region due to the removal of irradiated nuclear fuel through the nozzle. Therefore, NTR can only be launched after reaching orbits of at least 800 km.
The propellant is not radioactive, so NTR don't have to turn on at 800 km high. But the guts certainly are.
This was more of a joke about the idea that was common in the 1950s that a single type of vehicle, if it had the proper engine, could do all of the required phases. I have no particular love for NTRs.
Regarding historical designs I think SpaceX has found a way to carry out Arthur C Clarke's vision of a two stage fully reusable launcher system as shown in 2001 A Space Odyssey, but that the carrier aircraft has been replaced by a tail landing rocket and the orbiter has been converted to the same solution.
Was tail landing even possible for a rocket before modern control systems and the DC-X?
I guess the moon lander answers that question, up to a point...
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There was an all in one rocket. Way before the compromises of the space program and the identification of operational problems, the nuclear powered rocket provided the required transportation system. It's the most sensible idea, it's just been very difficult to put into practice.
Unfortunately no. A thermal nuclear engine (NTR engine) does not provide enough thrust to launch from the surface of the Earth, so a booster will be required. In addition, NTR provides a strong radioactive contamination of a large launch region due to the removal of irradiated nuclear fuel through the nozzle. Therefore, NTR can only be launched after reaching orbits of at least 800 km.
The propellant is not radioactive, so NTR don't have to turn on at 800 km high. But the guts certainly are.
This was more of a joke about the idea that was common in the 1950s that a single type of vehicle, if it had the proper engine, could do all of the required phases. I have no particular love for NTRs.
Regarding historical designs I think SpaceX has found a way to carry out Arthur C Clarke's vision of a two stage fully reusable launcher system as shown in 2001 A Space Odyssey, but that the carrier aircraft has been replaced by a tail landing rocket and the orbiter has been converted to the same solution.
Was tail landing even possible for a rocket before modern control systems and the DC-X?
I guess the moon lander answers that question, up to a point...
The combination of faithful computation fluid dynamics (CFD), control theory, and experience in working with stainless steel in large quantities out in the open is something that happened in about the last 20 years.
The CFD enables the reusable engines with reasonably good Isp and high TWR, as well as the heat shield.
The control theory enables tail landings (really tail down caught landings)
The materials engineering and know-how enable cheap manufacturing.
And finally a brilliant entrepreneur who ignores the current limitations and works it this new combination and ignores the naysayers. Always need that for a breakthrough.
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I can think of a couple of technologies which are necessary for an all-in-one vehicle architecture, each of which was at some point considered impossible™
- 1st stage reuse a'la F9
- GPS and control algorithms (convexification was developed only in 200x)
- engine clustering (everyone was afraid of it)
- supersonic retropropulsion
- FFSC / Methane (pure CH4 + ISRU works only with FFSC+subcooling)
- propellant transfer/depots
- docking / proximity ops. (people were afraid of this)
- long term cryo management
- ISRU
Least not least: first principles thinking/optimization, getting rid of the ISP obsession (hydrogen and NTR)
In other words, even if you thought about it and proposed a project with so many low-TRL techs, you'd be laughed off.
(did I forget something?)
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I can think of a couple of technologies which are necessary for an all-in-one vehicle architecture, each of which was at some point considered impossible™
- 1st stage reuse a'la F9
- GPS and control algorithms (convexification was developed only in 200x)
- engine clustering (everyone was afraid of it)
- supersonic retropropulsion
- FFSC / Methane (pure CH4 + ISRU works only with FFSC+subcooling)
- propellant transfer/depots
- docking / proximity ops. (people were afraid of this)
- ISRU
Least not least: first principles thinking/optimization, getting rid of the ISP obsession (hydrogen and NTR)
In other words, even if you thought about it and proposed a project with so many low-TRL techs, you'd be laughed off.
(did I forget something?)
NASA Propellant depots was declared non usable by Congressional fiat (senator Shelby)
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NASA Propellant depots was declared non usable by Congressional fiat (senator Shelby)
Sure, but even if allowed, it is still something on a critical path you have to develop. Another low-TRL tech in your proposal adding to your costs.
The 'people were afraid of this'. I did not mean politically/business-wise, but technically. There were people worrying about proxops/dockings ("oh no, ±12 dockings to the depot, immensely complex & high risk"). 10-15 years ago people wondered about autonomous rendezvous (despite Soyuz doing it regularly).
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- FFSC / Methane (pure CH4 + ISRU works only with FFSC+subcooling)
Actually this one isn't necessary per se. Starship has significant overperformance when flying to Mars and quite a bit of overperformance for a single stage fly back. Starship dV is about 6.5 to 6.9km/s while 4.3km (3.6 TMI and 0.7 landing burn) is needed to get there and 5.9km/s to return (5.6 direct launch towards the Earth, 0.3 landing burn).
You could cut ISP 10% and things would still work.
And you could trade a bit of cargo space with tanks if a need arose.
Where FFSC and stuff comes handy is cislunar ops and things like launch stuff to GTO.
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NASA Propellant depots was declared non usable by Congressional fiat (senator Shelby)
Sure, but even if allowed, it is still something on a critical path you have to develop. Another low-TRL tech in your proposal adding to your costs.
The 'people were afraid of this'. I did not mean politically/business-wise, but technically. There were people worrying about proxops/dockings ("oh no, ±12 dockings to the depot, immensely complex & high risk"). 10-15 years ago people wondered about autonomous rendezvous (despite Soyuz doing it regularly).
They were (and still are) also worried about something wrong happening during cryogenic propellant transfer.
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Isn't this all-in-one architecture driven almost entirely by the requirement for a cheap system for primarily one-way transport?
If you are mainly moving things from Earth to Mars, and you want your vehicles to be reusable (because they can't be cheap if not) then you have to get your Earth->Mars vehicle back to Earth. Once you have that requirement, the single vehicle architecture flows almost naturally, especially if you want to benefit from aero-braking/capture.
If you don't have that requirement then you are likely better off with multiple vehicles, getting progressively smaller - staging, basically.
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Many good reasons discussed in these threads for not seeing "all-in-one" before. I think the biggest, and maybe only one remaining, is sufficient demonstration of the new technologies that will make it possible, moving the idea from Sci-Fi to realistically possible. In the process becoming more feasible than the multi-system alternatives.
I imagine I am not the only one that found NASA Administrator Nelson's tweet an encouraging indication of where NASA is on their internal debate along this path to seeing officially coherent or compatible NASA and SpaceX Mars mission system architectures.
https://twitter.com/senbillnelson/status/1624139186918854657
It was great to see @SpaceX take a big step forward with Starship's hot fire test!
Starship is integral to @NASA’s Moon to Mars architecture and helping us land astronauts on the Moon. SpaceX’s success is NASA’s success is the world’s success.
Has he ever before acknowledged Starship's "integral" role in NASA's Mars architecture?
What would mark an official public move away from Apollo architecture (MTV) to the single ship system architecture? Official public recognition by NASA and Congressional funding shifts are indispensable.
I think that a big NASA marker will come with a NASA RFP release, asking for new Mars Mission concepts including cost estimates, which contains constraints or points awards (e.g. orbital refueling, reuse) that will push competitive proposals away from the Apollo/MTV strategy.
What do you think? When do you think that RFP will emerge?:
1. Starship Orbital launch success
2. Starship EDL success
3. Orbital refueling demo (internal to ship) success
4. Orbital refueling demo (ship-to-ship) success
5. Lunar landing demo success
6. Artemis 3 success with full orbital refueling, lunar landing and takeoff.
7. Other or later?
I tend to think the first 4 are needed, but the last one will be #4 and should emerge in 2023. By this measure, a Mars concept update RFP could show up late 2023 or early 2024.
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<snip>
I think that a big NASA marker will come with a NASA RFP release, asking for new Mars Mission concepts including cost estimates, which contains constraints or points awards (e.g. orbital refueling, reuse) that will push competitive proposals away from the Apollo/MTV strategy.
What do you think? When do you think that RFP will emerge?:
1. Starship Orbital launch success
2. Starship EDL success
3. Orbital refueling demo (internal to ship) success
4. Orbital refueling demo (ship-to-ship) success
5. Lunar landing demo success
6. Artemis 3 success with full orbital refueling, lunar landing and takeoff.
7. Other or later?
I tend to think the first 4 are needed, but the last one will be #4 and should emerge in 2023. By this measure, a Mars concept update RFP could show up late 2023 or early 2024.
If it is the historical NASA administration structure and personnel. Probably too late to influence the current SpaceX plan of record. Since points 1 through 6 could happen in a very short period of time. Then NASA will have the choice of taking what ever SpaceX will offer or be shunted off to the sideline.
NASA administrator Nelson should worry that NASA might not be integral to SpaceX's Mars plans. SpaceX might not even submit a RFP proposal.
But back to the thread's subject. As others has hinted in previous posts. No one previously has the ability to control all facets of a development program for a very large space vehicle that is largely done inhouse with the very vertically integrated company of the program instigator. Heck, even the Mars surface exclusion suits is very likely to come from SpaceX. No one else is even planning for Mars surface suits now.
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One reason I think it hasn't been done before is that traditional NASA first order cost estimation was based on weight. So if your Mars lander was allocated 1000 kg, it would cost a certain amount, and if you allowed 2000 kg, it would cost twice as much. There was (and probably still is) no methodology in NASA to redesign it to be CHEAPER because it could be heavier, more weight allowance means add more exotic instruments.
Therefore, the cheapest possible way to do a Mars mission was to design specialized parts for each mission segment, like Apollo did, each as light as possible. Since it would still be super expensive, you certainly aren't going to try to figure out ways to build 20 or 100 of them to reduce costs. Look at the tiny discount Boeing is offering for building more SLS launchers.
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I can't understand why people think integrated spacecraft ( "all-in-one" / same vehicle) is a good idea.
for instance.
It is like the transportation system between cities in a country. Cars, public transport systems, trains and planes are used for commuter transportation and logistics within and between cities, including different fields.
Why do you think that an integrated single system can solve everything?
Starship is like a large tanker. Do you drive your children to school every day?
I can understand why some people don't like landing on the moon with starship.
I think the core reason is that the starship is too big and heavy.
Landing on an extraterrestrial object without a ground support system is too risky. It must be hardened with high strength, a very flat landing site, and a high-precision global positioning system.
Look at the ground environment and conditions required for starship launch. How can these be reconstructed on the moon or Mars in the short term?
The cement surface hardness of the airport and rocket launch site is 10-11.
The surface hardness of the surface of the moon and Mars is estimated to reach 7.
The key issue is flatness.
The aspect ratio of starship is 5:1.
The ground of the celestial body is uneven or defective, plus it has a large dead weight. It is easy to overturn.
A lander with a weight of less than 20 tons and a ratio of length to diameter of 2:1 is equipped with an open landing leg.
It is much more reliable than a few hundred tons of starship.
It is not difficult to choose whether it is easy to erect a squat cube or a long columnar body.
So I also think starship is more suitable for leo rail transportation.
The space mission outside the deep space should be SH+one-time upper level+load.
Finally, what is the great value of colonizing Mars?
What the government does is explore and explore, just to understand the planets beyond the earth. So just send an expedition team.
Musk wants to colonize Mars. The question is why send so many people to Mars? There is no economic value or commercial interest, and it needs to continuously transport materials from the earth to barely maintain the existence of people on Mars. As a transportation enterprise, Musk is happy with such a large demand for transportation capacity. Who will pay for the cost of Mars colonization?
The bucket theory is that the water in the bucket is determined by the shortest board. In the matter of Mars colonization/bucket. Spacex is the only long piece of wood. No one wants to really invest in it except Spacex and Musk. To solve the problem of interstellar migration and survival, it will take the joint efforts of the industry of a country and even the industry of all countries on the planet to complete it. Can the Musks really succeed if they only work hard? This is the problem to be considered.
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As far as I understand, there is no such thing, as NASA Mars architecture right now. All the previous Mars Design Reference Missions assumed several HLV launches per synod. If the NASA HLV is SLS, which can fly only once a year, then the earlier RDMs have become obsolete by now. Well, if Moon & Mars considered together, then Starship is a part of it, because it is a part of the Moon leg. But these are words only, as nobody knows, how to continue Artemis to Mars.
Currently, the only justification of using SLS for Artemis together with Starship is that the second one is not considered sufficiently safe for Earth launch and EDL. When this problem is over, SLS will become obsolete and untenable. Shotwell said that they want 100-200 successful Starship flights before trying it with humans. So, this is the requirement. Not just a single EDL, but a hundred. On the other hand, orbital refueling is already assumed for Artemis Moon.
I have no idea, when the 100 successful Starship EDL will be achieved. Maybe, Artemis with SLS+Starship will be unstoppable by then. Nevertheless, probably it would happen earlier than any NASA decision about Mars.
I expect the next NASA Mars DRM is based on SpaceX hardware.
Of course, the other possibility is emergence of a serious obstacle in Starship development. Then, development of SLS will be considered retrospect as the right move.
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I can't understand why people think integrated spacecraft ( "all-in-one" / same vehicle) is a good idea.
for instance.
It is like the transportation system between cities in a country. Cars, public transport systems, trains and planes are used for commuter transportation and logistics within and between cities, including different fields.
Why do you think that an integrated single system can solve everything?
Starship is like a large tanker. Do you drive your children to school every day?
I can understand why some people don't like landing on the moon with starship.
I think the core reason is that the starship is too big and heavy.
Landing on an extraterrestrial object without a ground support system is too risky. It must be hardened with high strength, a very flat landing site, and a high-precision global positioning system.
Look at the ground environment and conditions required for starship launch. How can these be reconstructed on the moon or Mars in the short term?
The cement surface hardness of the airport and rocket launch site is 10-11.
The surface hardness of the surface of the moon and Mars is estimated to reach 7.
The key issue is flatness.
The aspect ratio of starship is 5:1.
The ground of the celestial body is uneven or defective, plus it has a large dead weight. It is easy to overturn.
A lander with a weight of less than 20 tons and a ratio of length to diameter of 2:1 is equipped with an open landing leg.
It is much more reliable than a few hundred tons of starship.
It is not difficult to choose whether it is easy to erect a squat cube or a long columnar body.
So I also think starship is more suitable for leo rail transportation.
The space mission outside the deep space should be SH+one-time upper level+load.
Finally, what is the great value of colonizing Mars?
What the government does is explore and explore, just to understand the planets beyond the earth. So just send an expedition team.
Musk wants to colonize Mars. The question is why send so many people to Mars? There is no economic value or commercial interest, and it needs to continuously transport materials from the earth to barely maintain the existence of people on Mars. As a transportation enterprise, Musk is happy with such a large demand for transportation capacity. Who will pay for the cost of Mars colonization?
The bucket theory is that the water in the bucket is determined by the shortest board. In the matter of Mars colonization/bucket. Spacex is the only long piece of wood. No one wants to really invest in it except Spacex and Musk. To solve the problem of interstellar migration and survival, it will take the joint efforts of the industry of a country and even the industry of all countries on the planet to complete it. Can the Musks really succeed if they only work hard? This is the problem to be considered.
I'd strongly recommend you actually read what has been written before making such general statements. All your points have been answered long ago. Espeically if most of your points are severely lacking.
* Mars is not dropping children at school, the analogy is nonsense. And yes, people were using same carts for many different functions long before specialization happened. WRT space we're in early carts age not modern intercity communication age.
* The Earth has much stronger gravity than either Moon or Mars. Your talk about ground equipment misses this so badly. BTW a possible (and definitely workable) solution for HLS landing was long presented by SpaceX: landign engines high up on the vehicle.
* We do have mapped surfaces of both Moon and Mars with sub meter accuracy. And we already landed within meters of the target spot on Mars (and did so using platform with parachuted for a significant portion of descent). Toppling is not a significant issue
* The significant issue would be reliability of active elements of the vehicle. Lack of redundancy of most landers is high risk factor. Starship happens to have redundancies and this is what counts most.
* The value of colonizing Mars has been discussed a lot. This is off topic here. Suffice to say, that the return (scientific, quality of life, solutions to problems) has been regularly the greatest form bold endeavors for which those solutions were mere "scaffoldings" or side effects. At the same time most programs to create solutions for the sake of those solutions have failed or were at best very poor cost to gain ratio.
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- FFSC / Methane (pure CH4 + ISRU works only with FFSC+subcooling)
Actually this one isn't necessary per se. Starship has significant overperformance when flying to Mars and quite a bit of overperformance for a single stage fly back. Starship dV is about 6.5 to 6.9km/s while 4.3km (3.6 TMI and 0.7 landing burn) is needed to get there and 5.9km/s to return (5.6 direct launch towards the Earth, 0.3 landing burn).
You could cut ISP 10% and things would still work.
And you could trade a bit of cargo space with tanks if a need arose.
Where FFSC and stuff comes handy is cislunar ops and things like launch stuff to GTO.
This makes me wonder if TSTM might be feasible. Splitting the dv 7.5km/s for the booster and 7.5km/s for the MTV/lander/2nd stage. Landing the booster on a barge. No propellant transfer to mess about with.
Use a modified 9 Raptor starship as the booster and build the mars vehicles with low chamber-pressure vacuum engines and parachute recovery on earth for the few that come back.
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I immediately thought of the Phoenix SSTO concept vehicle from the 1980s, that was supposed to eventually be an "all in one" type Mars lander.
http://www.astronautix.com/p/phoenixc.html
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I can't understand why people think integrated spacecraft ( "all-in-one" / same vehicle) is a good idea.
for instance.
It is like the transportation system between cities in a country. Cars, public transport systems, trains and planes are used for commuter transportation and logistics within and between cities, including different fields.
Why do you think that an integrated single system can solve everything?
Starship is like a large tanker. Do you drive your children to school every day?
I can understand why some people don't like landing on the moon with starship.
I think the core reason is that the starship is too big and heavy.
Landing on an extraterrestrial object without a ground support system is too risky. It must be hardened with high strength, a very flat landing site, and a high-precision global positioning system.
Look at the ground environment and conditions required for starship launch. How can these be reconstructed on the moon or Mars in the short term?
The cement surface hardness of the airport and rocket launch site is 10-11.
The surface hardness of the surface of the moon and Mars is estimated to reach 7.
The key issue is flatness.
The aspect ratio of starship is 5:1.
The ground of the celestial body is uneven or defective, plus it has a large dead weight. It is easy to overturn.
A lander with a weight of less than 20 tons and a ratio of length to diameter of 2:1 is equipped with an open landing leg.
It is much more reliable than a few hundred tons of starship.
It is not difficult to choose whether it is easy to erect a squat cube or a long columnar body.
So I also think starship is more suitable for leo rail transportation.
The space mission outside the deep space should be SH+one-time upper level+load.
Finally, what is the great value of colonizing Mars?
What the government does is explore and explore, just to understand the planets beyond the earth. So just send an expedition team.
Musk wants to colonize Mars. The question is why send so many people to Mars? There is no economic value or commercial interest, and it needs to continuously transport materials from the earth to barely maintain the existence of people on Mars. As a transportation enterprise, Musk is happy with such a large demand for transportation capacity. Who will pay for the cost of Mars colonization?
The bucket theory is that the water in the bucket is determined by the shortest board. In the matter of Mars colonization/bucket. Spacex is the only long piece of wood. No one wants to really invest in it except Spacex and Musk. To solve the problem of interstellar migration and survival, it will take the joint efforts of the industry of a country and even the industry of all countries on the planet to complete it. Can the Musks really succeed if they only work hard? This is the problem to be considered.
I'd strongly recommend you actually read what has been written before making such general statements. All your points have been answered long ago. Espeically if most of your points are severely lacking.
* Mars is not dropping children at school, the analogy is nonsense. And yes, people were using same carts for many different functions long before specialization happened. WRT space we're in early carts age not modern intercity communication age.
* The Earth has much stronger gravity than either Moon or Mars. Your talk about ground equipment misses this so badly. BTW a possible (and definitely workable) solution for HLS landing was long presented by SpaceX: landign engines high up on the vehicle.
* We do have mapped surfaces of both Moon and Mars with sub meter accuracy. And we already landed within meters of the target spot on Mars (and did so using platform with parachuted for a significant portion of descent). Toppling is not a significant issue
* The significant issue would be reliability of active elements of the vehicle. Lack of redundancy of most landers is high risk factor. Starship happens to have redundancies and this is what counts most.
* The value of colonizing Mars has been discussed a lot. This is off topic here. Suffice to say, that the return (scientific, quality of life, solutions to problems) has been regularly the greatest form bold endeavors for which those solutions were mere "scaffoldings" or side effects. At the same time most programs to create solutions for the sake of those solutions have failed or were at best very poor cost to gain ratio.
Don't forget aerobraking. It makes a massive difference to Earth/Mars transport in a way that has absolutely no analogy in terrestrial transport.
You need to get your payload to the destination, which means imparting the necessary delta-v to it, and you then need to cancel that delta-v before reaching the surface. Aerobraking is by far the best way to do this.
Assuming you want full reusability (and it you don't, your terrestrial transport analogy fails entirely) then everything you gave that delta-v to needs to aerobrake.
Then you need to do the same thing in the opposite direction, unless you want all your hardware to just pile up at one end (in which case your terrestrial transport analogy fails again).
Given all those constraints, all-in-one just works out better.
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I've had the impression, ever since the 2016 presentation, that the real dealmaker was supersonic retro propulsion, demonstrated in the Earth's high atmosphere with Falcon9. Before that was demonstrated, any mission would have required more than one vehicle, limited to fairly low mass cargo.
From supersonic retro propulsion came aerobraking, that allows for shorter transfer times.
With aerobraking nuclear propulsion could be discarded.
Without nuclear, chemical could do the work with refueling.
I think it's a lucky coincidence that makes the second stage of the Earth launcher adequate as a single stage rocket for Mars, with a reduced capacity return to Earth. But that is was a nice to have.
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I still think the first landing of an un-manned StarShip variant on any surface (Moon, Mars, Asteroid, Moons of Mars...) should contain electric Tesla derived construction equipment and appropriate power generation systems for the target (solar, chemical, nuclear... whatever) to power the Tesla derived equipment. It's better if preceded by a seeding of StarLink derived sats with lasers back to the Earth StarLink system for high-bandwidth streams for talking with the equipment AIs. The job of the first ship should be to build landing pads and human shelters before landing more StarShips. Perhaps the second landing for Mars and maybe the Moon should be another un-manned StarShip with the moon/mars appropriate methane factory for future launches built into it. This would need to have a resource feed built for it, be connected to the power systems the first StarShip installed and feeds created to the other landing/launch pads built by the first landed StarShip system. This would leave a small crude spaceport for following StarShips to use.
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It is like the transportation system between cities in a country. Cars, public transport systems, trains and planes are used for commuter transportation and logistics within and between cities, including different fields.
Why do you think that an integrated single system can solve everything?
Starship is like a large tanker. Do you drive your children to school every day?
While others here have done a great job explaining the rocket-engineering reasons an "integrated single system" is a good fit for Earth-Mars transportation (aerobraking, etc.), I want to take a moment to address this point at a higher level, since it is a broader dichotomy that gets debated frequently, yet people often end up talking past each other on it, perhaps for lack of shared cultural context of how this works (or doesn't work) in practice for many people in their daily lives in different parts of the world.
I'm guessing you are writing from a region where specialized public transport systems are common and personal cars are considered to be of limited use (Europe perhaps?), but in America, it is common for parents to drive their children to school every day in personal automobiles. Many do in fact take communal school buses (which are school-specific systems that operate usually in areas where there are no municipal buses or trains, which is to say, most of the country); but a great many choose instead to drop their kids off by car along a commute to/from work, or as standalone trips by a stay-at-home parent. Part of the reason American states generally allow adolescents to start learning to drive at 16 (I believe this is substantially younger than in most European countries), and even to apply for restrictive permits at that age that allow them to drive solo to limited destinations (like schools and jobs), is because parents often buy/pass-on an extra (usually old and cheap) car for their children at that age so they can drive themselves to school. Even in areas where buses are available, driving oneself is typically far preferable, because it saves a huge amount of time and hassle not having to wait while the bus spends more time stopping at everyone's house than it actually does on the road. A 10-minute drive in a personal car can turn into a two-hour waste of time when riding a school bus with frequent stops.
More broadly, Americans famously love their personal automobiles (much to the chagrin and befuddlement of academic city-planner types) for exactly this reason. It's not about achieving optimal mile-by-mile efficiency in terms of fuel or ridership-capacity utilization. It's about optimizing at a broader level for total economic costs, monetary and otherwise, that families incur when choosing transportation. "Time is money", so if you can save hours every day driving yourself to work or school in a personal automobile (even as the only occupied seat in a 7-seat minivan or SUV), the gained productivity can greatly outweigh the extra costs in fuel and vehicle maintenance. This is not always easily expressible in one-dimensional dollar-value analysis: the time gained can be traded off for more affordable housing (e.g. farther from a workplace), or for more abstract gains like time for recreation or cultural enrichment activities (arts, sports, etc.). The equation only starts tipping the other way when an area has been developed to the point of extreme constraints in space, pollution, etc., as seen in dense cities like New York City, where personal automobiles have become impractical outside of limited uses and "Europe-style" specialized infrastructure is most appropriate.
This is similar to the tradeoffs SpaceX made with the Falcon 9 architecture, and is making with Starship, that tend to defy academic conventional wisdom as to "efficiency". People said for years (on this forum and elsewhere, including major launch company CEOs) that Falcon 9 could never be truly competitive in GTO/GEO launches because it had a high-thrust kerolox upper stage instead of a high-Isp hydrolox stage like Centaur/RL-10. Yet nobody's laughing now, as F9's high economics of scale - achieved by having "one system for everything" - made it cheaper than its competition even on an expendable basis (to say nothing of the reusability that becomes economically feasible only at such scale). Customers don't care that F9 is carrying more "dead weight" to high orbits using a "less efficient" fuel - they care that it can put their satellite in the desired orbit with delta-v to spare for a competitive price.
Early-stage Mars colonization needs an "American-style" integrated transport solution that sacrifices on-paper efficiency in specific engineering metrics for flexibility, resiliency, and economics of scale. Mars isn't ready for specialized "urban train and bus" style vehicles for the same reason most of America wasn't when it was first developed, and still largely isn't today. It will be a long time - generations or even centuries - before Mars is ready for "Europe-style" specialized transports like orbital shuttles and cyclers. Starship is the equivalent of the horse-drawn wagon or 4x4 pickup: far from the most efficient way to carry large quantities of goods or people along fixed, well-developed routes, but perfect when you're exploring and colonizing a wild land, and need the flexibility to make dynamic tradeoffs between different landing sites, cargo types, and in-situ vehicle uses (e.g. reusing Starships as early surface habs). None of it will seem "efficient" on paper according to conventional metrics, but it will be efficient in the one metric that really counts (especially in Musk's mind): generational time spent getting from where we are now to a self-sustaining Martian civilization.
This sense of urgency - however frivolous it may seem to those who think we have time to wait for a "better solution" - will have enormous knock-on benefits in accelerating science and engineering development, because it's all about shortening the "feedback loop" between discovery and innovating the next step. It really is all about "not letting the perfect be the enemy of the good enough", because getting started earlier lets us discover and develop new and better approaches that we never would've known we "needed" had we not stepped out and learned through doing. "Bootstrapping" a new civilization in a wild land with zero existing infrastructure requires that kind of dynamicity. The time for tight optimization in narrow dimensions will be much farther down the road once that initial groundwork has been laid.
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It is like the transportation system between cities in a country. Cars, public transport systems, trains and planes are used for commuter transportation and logistics within and between cities, including different fields.
Why do you think that an integrated single system can solve everything?
Starship is like a large tanker. Do you drive your children to school every day?
While others here have done a great job explaining the rocket-engineering reasons an "integrated single system" is a good fit for Earth-Mars transportation (aerobraking, etc.), I want to take a moment to address this point at a higher level, since it is a broader dichotomy that gets debated frequently, yet people often end up talking past each other on it, perhaps for lack of shared cultural context of how this works (or doesn't work) in practice for many people in their daily lives in different parts of the world.
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This sense of urgency - however frivolous it may seem to those who think we have time to wait for a "better solution" - will have enormous knock-on benefits in accelerating science and engineering development, because it's all about shortening the "feedback loop" between discovery and innovating the next step. It really is all about "not letting the perfect be the enemy of the good enough", because getting started earlier lets us discover and develop new and better approaches that we never would've known we "needed" had we not stepped out and learned through doing. "Bootstrapping" a new civilization in a wild land with zero existing infrastructure requires that kind of dynamicity. The time for tight optimization in narrow dimensions will be much farther down the road once that initial groundwork has been laid.
I have no intention of arguing too much on this topic.
I do not deny that integrated spacecraft can perform some deep space missions. It can meet the requirements of landing in the gravity well environment such as the earth, and also meet the requirements of landing in the environment of the moon and Mars.
I don't think this is an optimal solution.
In the history of aerospace, there have been many instances (or not very successful) of failure due to compatibility with too many requirements. For example, there are three models of A/B/C of F35.
The problem with StarShip is that part of his design is to access the earth's gravity well. At present, his payload module and the second stage rocket are rigidly connected. When he was sailing in deep space, he had to carry this part of the weight. This is why he is inefficient.
This design problem is also the reason why some people put forward the idea of SH+consumable upper level+load, which can better connect with the existing division of labor and technical architecture of the aerospace industry. The load will be more flexible. It can also carry out space missions more efficiently.
Another application prospect is to colonize Mars. At least 1 million tons of goods need to be transported. In this application scenario. The best plan is to plan according to the modern transportation system.
Each planet has its own transportation system, because the gravity traps of each celestial body vary greatly. There is another interstellar transport system between the planets. Only in this way can we meet the future.
What many people ignore is that when the large-scale space projects such as the real Mars colonization were launched, various deep space vehicle technologies had been solved or even matured. At that time, when we look at StarShip, we will feel that this plan is relatively primitive.
Now you agree with StarShip, but in the short term, only this plan seems to work.
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Don't forget aerobraking. It makes a massive difference to Earth/Mars transport in a way that has absolutely no analogy in terrestrial transport.
You need to get your payload to the destination, which means imparting the necessary delta-v to it, and you then need to cancel that delta-v before reaching the surface. Aerobraking is by far the best way to do this.
Assuming you want full reusability (and it you don't, your terrestrial transport analogy fails entirely) then everything you gave that delta-v to needs to aerobrake.
Then you need to do the same thing in the opposite direction, unless you want all your hardware to just pile up at one end (in which case your terrestrial transport analogy fails again).
Given all those constraints, all-in-one just works out better.
The size of starship is too large.
There is no atmosphere on the moon, and the atmospheric density of Mars is 1% of that of the earth.
The aerodynamic layout in and out of the earth's atmosphere is of no benefit to extraterrestrial objects.
This is why I think it is most effective for different celestial bodies to independently design spacecraft entering and exiting the gravity well.
Both the volume, weight and load are optimized. Instead of forcing various compatible designs.
For SH+disposable upper stage+loaded rocket. Different tasks only replace different loads.
Instead of leaving all the integration work to one company.
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The size of starship is too large.
That is an odd viewpoint, since for any human activity on Mars there will need to be a LOT of cargo transported to the surface of Mars, so the more cargo you can carry, the fewer vehicles and fewer trips you need to take. And vehicles costs money, as do trips, so money is an important consideration.
There is no atmosphere on the moon, and the atmospheric density of Mars is 1% of that of the earth.
Which doesn't matter. For the Moon that just means that you don't have to use an aerodynamically shaped vehicle, but it doesn't preclude you from using one either. And as it turns out, there is enough atmosphere on Mars to use it for aerobraking, which saves on the amount of propellant you need to haul to Mars. Win-Win.
The aerodynamic layout in and out of the earth's atmosphere is of no benefit to extraterrestrial objects.
This is why I think it is most effective for different celestial bodies to independently design spacecraft entering and exiting the gravity well.
Opinions are free, but unless you are going to go out and develop all this hardware, you are just a bystander. Give Elon Musk some credit here, in that he put his own money into starting SpaceX, and he worked hard to build a company that can now afford to invest in a viable space transportation system.
And I think Elon Musk would be the first to say that Starship should NOT be the only space transportation system, so there is no reason why you can't pursue your transportation system ideas.
Good luck with that, and give us periodic status reports on Twitter... ;)
Back to the general topic, I was actually the first to comment on this thread topic (https://forum.nasaspaceflight.com/index.php?topic=57141.msg2405597#msg2405597), and I wanted to add an addendum:
It is important to remember that there is NOT a business reason to build a transportation system that can reach the surface of Mars. None. And Elon Musk as stated that there won't be any significant revenue to be made by going to Mars.
So the simple answer to the original thread question is that there hasn't been an "all-in-one" (same vehicle) Mars architecture before now, because there hasn't been a big enough incentive to build one before now - regardless if it is possible or not.
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In the history of aerospace, there have been many instances (or not very successful) of failure due to compatibility with too many requirements. For example, there are three models of A/B/C of F35.
There're many many more instances where a multi-role multi-purpose vehicle has been implemented successfully. For example 747 has many variants of passenger and cargo versions, plus it also served as Shuttle Carrier, Airforce One, SOFIA, launched rockets for Virgin Orbit, acted as airborne laser platform, etc. Similarly 767 besides its passenger and cargo versions also has AWACS and tanker version.
And if we look beyond aerospace, single platform serving as basis for different vehicles are even more common, for example car companies usually builds multiple models of cars on the same platform, VW's platforms are listed here: https://en.wikipedia.org/wiki/List_of_Volkswagen_Group_platforms
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I'd strongly recommend you actually read what has been written before making such general statements. All your points have been answered long ago. Espeically if most of your points are severely lacking.
I know what you said. But I have never been convinced.
Because I can also put forward a lot of countervailing opinions for example.
* Mars is not dropping children at school, the analogy is nonsense. And yes, people were using same carts for many different functions long before specialization happened. WRT space we're in early carts age not modern intercity communication age.
I have explained this.
I want to remind you that you need to know. The current integrated spacecraft program is only a transition.
The real solution must be the cooperation of all kinds of professional and professional spacecraft to complete the super-scale interstellar space activities with the highest efficiency and lowest cost.
* The Earth has much stronger gravity than either Moon or Mars. Your talk about ground equipment misses this so badly. BTW a possible (and definitely workable) solution for HLS landing was long presented by SpaceX: landign engines high up on the vehicle.
A. I heard that Musk did not like the plan of deploying a circle of landing engines at the waist of StarShip. He repeatedly asked Nasa to use only Raptor to realize HLS landing. NASA finally agreed to carry out space missions beyond the Artemis plan. SpaceX can try according to its own ideas.
B. There are all replies I know about this question. But it didn't answer my question. The StarShip is still too heavy. On the surface without professional hardening, the stability and reliability of landing success is still unknown.
C. NASA chose StarShip as the contractor of HLS Annex H, not because it was really more scientific, but because all the plans were immature at that time, and SpaceX engineering capability was more efficient. The last key issue is that the price is low enough. So low that the opponent is automatically eliminated. This is also the reason why NASA's HLS program still has P attachments.
From what I know, NASA doesn't have much hope for StarShip-HLS
D. The celestial lander within 20 tons can set up a test simulation environment on the earth and complete all kinds of ground landing simulation through the pulley counterweight system. Including inclined surface, homing identification of landing site, etc., through hundreds of physical verification and simulation, high reliability landing survival is obtained. How to verify the simulation in advance for the weight level of StarShip? Just one Demo flight? Is SpaceX successful for the first time since the research and development began?
If SpaceX uses the landing system changed from Dragon Spacecraft. I won't have much worry and doubt. Because it is small enough. The Apollo program has verified that this weight level is not a problem.
The problem is StarShip. Landing on the moon is at least about M1A1 mass. It's still so high.
If the density of moon dust is uneven (one landing leg falls), or one landing leg encounters a crater or moon rock. What about the consequences?
In the Apollo era, designers were most worried about the landing scene. In the discussion of StarShip-HLS, I think many problems have been ignored
* We do have mapped surfaces of both Moon and Mars with sub meter accuracy. And we already landed within meters of the target spot on Mars (and did so using platform with parachuted for a significant portion of descent). Toppling is not a significant issue
On extraterrestrial bodies, we should land at high precision and repeatedly. Navigation satellite deployment is the best solution
Space imaging is not a navigation system.
* The significant issue would be reliability of active elements of the vehicle. Lack of redundancy of most landers is high risk factor. Starship happens to have redundancies and this is what counts most.
I don't think StarShip has much power redundancy when taking off from extraterrestrial objects.
In fact, I think the safety margin of StarShip is much smaller than that of other small spacecraft because of its huge size and weight.
* The value of colonizing Mars has been discussed a lot. This is off topic here. Suffice to say, that the return (scientific, quality of life, solutions to problems) has been regularly the greatest form bold endeavors for which those solutions were mere "scaffoldings" or side effects. At the same time most programs to create solutions for the sake of those solutions have failed or were at best very poor cost to gain ratio.
The more we understand the details of the development of modern space technology, the more we know how far away we are from colonial Mars.
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In the history of aerospace, there have been many instances (or not very successful) of failure due to compatibility with too many requirements. For example, there are three models of A/B/C of F35.
There're many many more instances where a multi-role multi-purpose vehicle has been implemented successfully. For example 747 has many variants of passenger and cargo versions, plus it also served as Shuttle Carrier, Airforce One, SOFIA, launched rockets for Virgin Orbit, acted as airborne laser platform, etc. Similarly 767 besides its passenger and cargo versions also has AWACS and tanker version.
And if we look beyond aerospace, single platform serving as basis for different vehicles are even more common, for example car companies usually builds multiple models of cars on the same platform, VW's platforms are listed here: https://en.wikipedia.org/wiki/List_of_Volkswagen_Group_platforms
One thing you have neglected is that these products are deformed in a comfortable working environment.
The working environment of StarShip in this part of the earth is relatively comfortable.
But at the other end of the deep space, it is extremely bad.
Bad living environment, bulky and clumsy aircraft. In fact, it is not necessarily good.
Your assumption is that it is easy and simple for StarShip to land and take off on extraterrestrial objects.
But from the takeoff and landing of the spacecraft now. The larger and more complex the aircraft, the greater the workload of various pre-flight inspection and maintenance.
StarShip on the earth has this condition, but there is no huge base on the moon and Mars. Not a good environment.
Just as StarShip is used for civil aviation and military transportation discussions. Civil aviation cargo transportation is still possible, while military application is of little significance.
In fact, this is the problem of StarShip's application in modern deep space.
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Don't forget aerobraking. It makes a massive difference to Earth/Mars transport in a way that has absolutely no analogy in terrestrial transport.
You need to get your payload to the destination, which means imparting the necessary delta-v to it, and you then need to cancel that delta-v before reaching the surface. Aerobraking is by far the best way to do this.
Assuming you want full reusability (and it you don't, your terrestrial transport analogy fails entirely) then everything you gave that delta-v to needs to aerobrake.
Then you need to do the same thing in the opposite direction, unless you want all your hardware to just pile up at one end (in which case your terrestrial transport analogy fails again).
Given all those constraints, all-in-one just works out better.
A The size of starship is too large.
B There is no atmosphere on the moon, and the atmospheric density of Mars is 1% of that of the earth.
C The aerodynamic layout in and out of the earth's atmosphere is of no benefit to extraterrestrial objects.
D This is why I think it is most effective for different celestial bodies to independently design spacecraft entering and exiting the gravity well.
E Both the volume, weight and load are optimized. Instead of forcing various compatible designs.
F For SH+disposable upper stage+loaded rocket. Different tasks only replace different loads.
G Instead of leaving all the integration work to one company.
You're taking the NASA approach as axiomatic (tons of different companies, custom totally different spacecraft for every single role, vehicles for as small of crew as possible, little commonality between stages, spacecraft, etc...)...
...Then of course we are extremely far from accomplishing the task SpaceX has taken.
If you start with the fact that SpaceX needed to figure out how to do G, since they can't force other companies to do their bidding, that the scale has to be enormous since the goal is settlement, that cash is limited... then an architecture like SpaceX describes pops right out, and the goal of settlement is much more feasible.
Everything has to be as reusable as possible. Ideally, over a 20-30 year timespan, you can reuse everything at least 10 times, if not 100 to 1000 times. You design with commonality with aerodynamic capability since the Moon is just not really relevant for a Mars architecture, and both Mars and Earth have atmospheres and transit time (and/or mass ratio) is MASSIVELY advantaged if your transfer vehicle is capable of aggressive aerocapture/reentry.
Forcing compatible designs is essentially the only way to enable mass-production of everything on a scale comparable to commercial airliners. This has an order of magnitude cost reduction by itself. Combined with high levels of reuse (especially for tankers, etc) which allow about 2 orders of magnitude reduction in cost, a massive scale that enables an order of magnitude reduction in cost, ISRU and aerocapture that allow an order of magnitude reduction in cost, plus optimization per-passenger, and you can achieve like 5-6 orders of magnitude reduction in per-passenger Mars transport cost, and have the beginning of a Mars settlement due to leveraging massive ISRU already.
"Oh, but SpaceX doesn't do it the way NASA does it." Yes, and the way NASA does it is in some ways forced, or at least strongly incentivized, by NASA's constraints of needing to rely on political funding. You need to "spread the wealth" to as many states as possible, as many companies as possible, appeasing defense contractors (which have powerful lobby arms) by giving them the lion's share of the funding, etc.
Starship is not really optimized for the Moon, but Starship HLS is a modification that allows it to serve this goal. It could be built to transport 100 people to the Moon on one go, but they're only carrying 2 (maybe 4 later on). The weakness of such a large vehicle serving such a small mission here is, if anything, NASA's own lack of ambition for lunar missions, not SpaceX for having the foresight to start creating a spacecraft that would enable what many think is impossible on Mars.
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One thing you have neglected is that these products are deformed in a comfortable working environment.
The working environment of StarShip in this part of the earth is relatively comfortable.
But at the other end of the deep space, it is extremely bad.
Different landing gears for different landing environment and landing/taking off in harsh environment has been done with aircraft, not that difficult.
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Don't forget aerobraking. It makes a massive difference to Earth/Mars transport in a way that has absolutely no analogy in terrestrial transport.
You need to get your payload to the destination, which means imparting the necessary delta-v to it, and you then need to cancel that delta-v before reaching the surface. Aerobraking is by far the best way to do this.
Assuming you want full reusability (and it you don't, your terrestrial transport analogy fails entirely) then everything you gave that delta-v to needs to aerobrake.
Then you need to do the same thing in the opposite direction, unless you want all your hardware to just pile up at one end (in which case your terrestrial transport analogy fails again).
Given all those constraints, all-in-one just works out better.
The size of starship is too large.
There is no atmosphere on the moon, and the atmospheric density of Mars is 1% of that of the earth.
The aerodynamic layout in and out of the earth's atmosphere is of no benefit to extraterrestrial objects.
This is why I think it is most effective for different celestial bodies to independently design spacecraft entering and exiting the gravity well.
Both the volume, weight and load are optimized. Instead of forcing various compatible designs.
For SH+disposable upper stage+loaded rocket. Different tasks only replace different loads.
Instead of leaving all the integration work to one company.
In addition to the answers above, most of these points are unrelated to the question in the thread title. When answering that question, the lack of atmosphere on the moon and other celestial bodies is irrelevant, and for that mission Starship is optimised.
No one is trying to answer the question: "is Starship be the only space transportation system that will ever be needed"
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Yes the OPs thread comments have zero to do with the thread title. Strikes me that the op just likes something like the BO/National team proposal and doesn’t like anything Starship/Spacex and is trying real hard to find problems with SS/HLS, which even NASA don’t appear to have.
May I suggest a change in title?
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It is like the transportation system between cities in a country. Cars, public transport systems, trains and planes are used for commuter transportation and logistics within and between cities, including different fields.
Why do you think that an integrated single system can solve everything?
Starship is like a large tanker. Do you drive your children to school every day?
While others here have done a great job explaining the rocket-engineering reasons an "integrated single system" is a good fit for Earth-Mars transportation (aerobraking, etc.), I want to take a moment to address this point at a higher level, since it is a broader dichotomy that gets debated frequently, yet people often end up talking past each other on it, perhaps for lack of shared cultural context of how this works (or doesn't work) in practice for many people in their daily lives in different parts of the world.
......
This sense of urgency - however frivolous it may seem to those who think we have time to wait for a "better solution" - will have enormous knock-on benefits in accelerating science and engineering development, because it's all about shortening the "feedback loop" between discovery and innovating the next step. It really is all about "not letting the perfect be the enemy of the good enough", because getting started earlier lets us discover and develop new and better approaches that we never would've known we "needed" had we not stepped out and learned through doing. "Bootstrapping" a new civilization in a wild land with zero existing infrastructure requires that kind of dynamicity. The time for tight optimization in narrow dimensions will be much farther down the road once that initial groundwork has been laid.
I have no intention of arguing too much on this topic.
I do not deny that integrated spacecraft can perform some deep space missions. It can meet the requirements of landing in the gravity well environment such as the earth, and also meet the requirements of landing in the environment of the moon and Mars.
I don't think this is an optimal solution.
In the history of aerospace, there have been many instances (or not very successful) of failure due to compatibility with too many requirements. For example, there are three models of A/B/C of F35.
The problem with StarShip is that part of his design is to access the earth's gravity well. At present, his payload module and the second stage rocket are rigidly connected. When he was sailing in deep space, he had to carry this part of the weight. This is why he is inefficient.
You're carried away by wrong analogies. There's no "sailing" in deep space (unless you have solar sails). It's free fall all the way. And in free fall you don't carry anything, all the mass carries itself.
Once you have accelerated into interplanetary transfer orbit, it doeasn't matter if the payload remains attached to the upper stage or not. The acceleration and carrying is now done. It's free fall up to the destination.
The difference is at the destination, but here the reusable upper stage with proper heat shield and aerodynamic system is actually of great use as it provides the whole deceleration part. And this is worth really a lot. Compare with Mars rovers: the actual surface payload is merely 40% of the mass entering the atmosphere. The whole extremely complex single use entry descent and landing had to be designed for the payload. In the case of Starship you have one vehicle type delivering numerous different payloads. And lo and behold those payloads add to ~40% of the mass entering the atmosphere. You lose nothing, and keep the money not spent on developing separate entry vehicles for each payload.
This design problem is also the reason why some people put forward the idea of SH+consumable upper level+load, which can better connect with the existing division of labor and technical architecture of the aerospace industry. The load will be more flexible. It can also carry out space missions more efficiently.
More efficiently my what metric?
Money? Time spent? Propellant mass? Total mass? Energy use? The number of devils on a pin head?
Only 1st two metrics from the above least have any type of importance. The rest are irrelevant.
Another application prospect is to colonize Mars. At least 1 million tons of goods need to be transported. In this application scenario. The best plan is to plan according to the modern transportation system.
Each planet has its own transportation system, because the gravity traps of each celestial body vary greatly. There is another interstellar transport system between the planets. Only in this way can we meet the future.
What many people ignore is that when the large-scale space projects such as the real Mars colonization were launched, various deep space vehicle technologies had been solved or even matured. At that time, when we look at StarShip, we will feel that this plan is relatively primitive.
Now you agree with StarShip, but in the short term, only this plan seems to work.
Modern transportation systems shifts more mass in 2 hours than it would be total for the initial colony over 20 years. Moreover, they take advantage of local infrastructure at every destination. Your way of meeting the future looks like magically being in the future. But there's no magic and you're always in the present, and you could only use the infrastructure (or lack thereof) of the present.
NB. planets are not stars, there's no need for any interstellar transport between planets in our solar system.
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Thinking of the title thread, I see a few main issues which related to reuse (if you want an all in one architecture, reuse has to be figured out). The design of the vehicle gets tricky as it has to be able to deal with the Aero forces on the way up, but more importantly, has to deal with them on the way down as well. Of course this is true for Mars as well. And when you start getting close to the ground, how are doing to slow it down enough to prevent too much lithobraking.
I can think of three vehicle architectures that could be made into an "all in one" type system - or really, just reusable upper stages.
1. Spaceplanes
2. Starship-like system with movable body flaps
3. Capsule
Each one has its own pros and cons, however my personal favourite is the capsule type system that propulsively lands. Stoke's upper stage (or a system like it) could conceivably be used anywhere in the solar system as well, including Mars.
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In the near term, the only planet it really makes sense to establish regular travel to is Mars. Venus stuff requires cloud-level floating cities and is a much harder target for settlement for that reason. The Moon is close and therefore good for tourism and scientific study but lacks the resources you need for settlement. The gas giants have the same problem as Venus but worse.
The moons of the gas giants offer more tantalizing options, but the inner 3 of the 4 large moons of Jupiter have high surface radiation, leaving you with Callisto, which isn’t in any way superior to Mars that I can tell. Saturn’s Titan is a really remarkable, if incredibly frigid, world. That’s an interesting option, but the distance is incredibly vast. Uranus’ Oberon and Neptune’s Titania offer Pluto-like options that aren’t vastly better than Mars.
There’s also asteroids and other dwarf planets like Ceres and Vesta, but their gravity is very low. Mercury is Moon-like, but with possibility of high solar power and abundant metals, but very challenging to reach and with poorer resources than Mars.
So we have settlement of Mars, tourism to the Moon, and maybe some exploration missions to other destinations (maybe helium-3 and even helium-4 mining of Uranus if we perfect reusable nuclear thermal rockets which can use the hydrogen atmosphere as propellant).
Mars is the only place other than Earth that we’ve demonstrated oxygen and fuel (CO) production from in situ natural resources. We can gather water as well to make methane, which is an excellent rocket fuel for both boosters and upper stage. Half the sunlight of Earth, but an Earthlike day/night cycle which makes power storage during night feasible. The atmosphere is also enough to dump waste heat into to reduce the size of a nuclear reactor’s radiator. Carbon, oxygen, nitrogen, and even hydrogen (as H2O) can be extracted to some degree anywhere on the planet from the atmosphere. Iron-nickel metal is littering the surface and can just be picked up, no smelting required. Ore veins of other metals and of things like gypsum, etc, are plentiful. Ore (in the literal sense of minerals concentrated by a water cycle) is present on Mars in a way that it isn’t on the airless Moon and asteroids or cloud layers of Venus or the gas giants. The atmosphere, at likely landing altitudes, shields from all micrometeorites, from the vast, vast majority of solar flare effects, and (along with the planet itself) even from most galactic cosmic rays, plus allows propellantless flight (Ingenuity), aggressive aerobraking/capture/reentry/etc, and reduces the day/night temperature swings plus shields from virtually all hard vacuum UV. Mars is a pretty good choice for planetary settlement, the best we have other than Earth.
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...From what I know, NASA doesn't have much hope for StarShip-HLS
Then you don't know anything, because NASA won't be able to land humans on the surface of the Moon this decade without SpaceX and the Starship, and NASA is certainly planning on landing multiple missions on the Moon this decade.
Remember there are no other HLS landers under contract yet, and based on how long it took the Commercial Crew program to develop operational LEO spacecraft, it is likely to take 10 years or more for a second lander to be developed and made operational.
So NASA does have a LOT of hope that Starship will work, because otherwise the Artemis program is a failure.
But none of this is related to the thread topic, and you don't seem to want to talk about the thread topic. So please either stick to the topic, or go post your opinions about how Starship is not the right design for whatever on the more related threads. This thread was created to talk about "Why", not bash what SpaceX is actually doing... ::)
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"Why hasn't there been an "all-in-one" (same vehicle) Mars architecture before?"
For the same reasons why Starship will require multiple variants to accomplish Space X's Mars missions.
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I think one of the significant factors has been the half century of industry opinion that all crewed system need a separate launch escape system for all stages of launch.
SpaceX are definitely trying to change that mind-set, and thereby release a lot more performance from their system. That in turn has allowed this system to close the Mars mission performance goals more easily and helps to make this architecture viable.
Opinions on this are certainly divided. We've all heard the arguments ad infinitum, so let's NOT trawl all those points up again here on this thread. Suffice to say, only time, and whatever inevitable accident(s) the future will bring, will prove whether this was a good decision or not.
Ross.
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I'd strongly recommend you actually read what has been written before making such general statements. All your points have been answered long ago. Espeically if most of your points are severely lacking.
I know what you said. But I have never been convinced.
Because I can also put forward a lot of countervailing opinions for example.
* Mars is not dropping children at school, the analogy is nonsense. And yes, people were using same carts for many different functions long before specialization happened. WRT space we're in early carts age not modern intercity communication age.
I have explained this.
I want to remind you that you need to know. The current integrated spacecraft program is only a transition.
The real solution must be the cooperation of all kinds of professional and professional spacecraft to complete the super-scale interstellar space activities with the highest efficiency and lowest cost.
* The Earth has much stronger gravity than either Moon or Mars. Your talk about ground equipment misses this so badly. BTW a possible (and definitely workable) solution for HLS landing was long presented by SpaceX: landign engines high up on the vehicle.
A. I heard that Musk did not like the plan of deploying a circle of landing engines at the waist of StarShip. He repeatedly asked Nasa to use only Raptor to realize HLS landing. NASA finally agreed to carry out space missions beyond the Artemis plan. SpaceX can try according to its own ideas.
B. There are all replies I know about this question. But it didn't answer my question. The StarShip is still too heavy. On the surface without professional hardening, the stability and reliability of landing success is still unknown.
C. NASA chose StarShip as the contractor of HLS Annex H, not because it was really more scientific, but because all the plans were immature at that time, and SpaceX engineering capability was more efficient. The last key issue is that the price is low enough. So low that the opponent is automatically eliminated. This is also the reason why NASA's HLS program still has P attachments.
From what I know, NASA doesn't have much hope for StarShip-HLS
D. The celestial lander within 20 tons can set up a test simulation environment on the earth and complete all kinds of ground landing simulation through the pulley counterweight system. Including inclined surface, homing identification of landing site, etc., through hundreds of physical verification and simulation, high reliability landing survival is obtained. How to verify the simulation in advance for the weight level of StarShip? Just one Demo flight? Is SpaceX successful for the first time since the research and development began?
If SpaceX uses the landing system changed from Dragon Spacecraft. I won't have much worry and doubt. Because it is small enough. The Apollo program has verified that this weight level is not a problem.
The problem is StarShip. Landing on the moon is at least about M1A1 mass. It's still so high.
If the density of moon dust is uneven (one landing leg falls), or one landing leg encounters a crater or moon rock. What about the consequences?
In the Apollo era, designers were most worried about the landing scene. In the discussion of StarShip-HLS, I think many problems have been ignored
* We do have mapped surfaces of both Moon and Mars with sub meter accuracy. And we already landed within meters of the target spot on Mars (and did so using platform with parachuted for a significant portion of descent). Toppling is not a significant issue
On extraterrestrial bodies, we should land at high precision and repeatedly. Navigation satellite deployment is the best solution
Space imaging is not a navigation system.
* The significant issue would be reliability of active elements of the vehicle. Lack of redundancy of most landers is high risk factor. Starship happens to have redundancies and this is what counts most.
I don't think StarShip has much power redundancy when taking off from extraterrestrial objects.
In fact, I think the safety margin of StarShip is much smaller than that of other small spacecraft because of its huge size and weight.
* The value of colonizing Mars has been discussed a lot. This is off topic here. Suffice to say, that the return (scientific, quality of life, solutions to problems) has been regularly the greatest form bold endeavors for which those solutions were mere "scaffoldings" or side effects. At the same time most programs to create solutions for the sake of those solutions have failed or were at best very poor cost to gain ratio.
The more we understand the details of the development of modern space technology, the more we know how far away we are from colonial Mars.
This is severely misinformed. You're arguing from a mix of incredulity and misinformation.
You have very wrong image of how things are being developed and what is and what isn't hard. Do you know how Perseverance landed with high precision on Mars? It landed by using visual navigation, i.e. image recognition and matching to precise surface image. The technology to both know the areas without boulders larger than 20cm and how to navigate to such areas is already there in operational use. That you have no idea how it works or even its very existence doesn't make it false. Be more humble, and you'll make less confidently wrong statements.
And no, ensuring that vehicle won't topple and when it would topple is not achieved by some elaborate tests with test article suspended from a special crane. It's actually trivial to simply calculate maximum safe leaning angle of the vehicle.
I'd like to remind you that SpaceX knows how to land large and tall vehicle on an not fully stable platform. They did so over 100 times already.
Also, the hard part of both Mars and Earth atmospheric entry occurs in the air with pressure about 1:10000 of seal level, and both Earth and Mars atmospheres have such low pressure quite high above the ground (~60km on the Earth and ~40km on Mars). So yes, both planets are similar enough to use same reentry vehicle on both.
IOW, you have failed to demonstrate sufficient understanding of "the details of the development of modern space technology", so while you're obviously entitled to your opinion, it doesn't have much weight.
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This is severely misinformed. You're arguing from a mix of incredulity and misinformation.
My source of information is not confused. But the judgment process of most space enthusiasts is too hasty
You have very wrong image of how things are being developed and what is and what isn't hard. Do you know how Perseverance landed with high precision on Mars? It landed by using visual navigation, i.e. image recognition and matching to precise surface image. The technology to both know the areas without boulders larger than 20cm and how to navigate to such areas is already there in operational use. That you have no idea how it works or even its very existence doesn't make it false. Be more humble, and you'll make less confidently wrong statements.
You said that the landing process of Persevere is a link of terminal guidance and homing.
Now, almost all the automatic vertical landing processes of extraterrestrial objects have this technology.
The problem is that the range of the terminal guidance homing correction route is also very limited.
Why it is necessary to do high-precision fixed-point repeated landing similar to GPS navigation is related to the mission.
Every process in the re-entry process is very important, especially the navigation and positioning in the early and middle stages of the descent process.
In fact, this is not a very difficult technical problem for the United States. The real problem is the budget. The establishment of GPS systems for extraterrestrial objects is very important for the establishment of bases on the moon and Mars. The higher the degree of automation, the higher the precision of repetition, the more they are needed for fixed point landing. And you turn a blind eye.
The terminal guidance process (navigation process) before landing. This involves my other point of view.
NASA's Mars probe Persevere is a small lander. It is easy to correct its position during terminal guidance.
Its speed can be controlled to hover, which requires a lot of fuel reserves and enough attitude control engines. It is convenient to avoid obstacles in the air.
The landing of Falcon 9 has no near-hovering speed reduction and obstacle avoidance process. It also lacks technical means to avoid obstacles at very low speeds. StarShip is even more uncertain.
One problem you ignore is that I have repeatedly stressed that StarShip is too big and heavy. What perseverance can do is not necessarily what StarShip can do. This is why I think NASA will support the landing of a traditional lander with a capacity of less than 20 tons on the moon.
And no, ensuring that vehicle won't topple and when it would topple is not achieved by some elaborate tests with test article suspended from a special crane. It's actually trivial to simply calculate maximum safe leaning angle of the vehicle.
You know too little about hardware-in-the-loop simulation.
The physical simulation and simulation of the landing scene of an extraterrestrial planet is a very complex part with a lot of test contents, which ensures the high reliability of the mission. It is not just to calculate several dip angles. The establishment of this experimental environment costs far more money and manpower than ordinary people imagine. The period required for the experiment is also very long.
For most formal space missions, only when the physical simulation of various technologies is close to the technical maturity of 6 (the full score is 8-9) or above can the real launch mission be executed. StarShip can complete the technical prototype, but can't actually test it. Because it is too large and heavy to build a simulation experiment environment. It can only be directly verified in the actual environment outside the ground. This is a radical technology development route.
For people engaged in technology, its technical maturity is only 2 or 3. The risk is not much lower than the unmanned lunar exploration and Mars missions of the former Soviet Union. Because the former Soviet Union failed because it was in a hurry and in addition, it was to save money. If the technology maturity is not enough, the probability of failure is far greater than that of success.
I'd like to remind you that SpaceX knows how to land large and tall vehicle on an not fully stable platform. They did so over 100 times already.
You can see how different the two are by carefully comparing the landing conditions
1. The landing environment of the earth should be leveled in advance.
If the landing site is paved with cement according to the airport standard. Generally, there will also be high-strength cement with a thickness of 1-2 meters.
The surface hardness is above 10-11.
It means a rocket landing of dozens of tons (the landing mass of Falcon 9 rocket is about 20 tons), and there is no need to worry about the ground leveling problem. There is no need to worry about the undulation under the lunar soil, or the uncertain problems such as stones (you can't see under the soil layer with laser imaging). There is no need to worry about collapse.
The moon is a little better. The surface of Mars has a lot of problems. The shallow surface and the surface below contain water ice.
It looks like a flat landing site. It's not a big problem for a few hundred kg lander.
This kind of surface, a large spaceship with a total weight of one or two hundred tons, can only land on the landing leg. I dare not think about the consequences.
2. Generally, the lander is still possible to correct the 3-5 degree inclined surface,
But what should you do if your tilt scene is more than 5 degrees or even 10 degrees?
I have read some documents on the analysis of landing scenarios of landers, considering the existence and size of meteorite craters.
The technical requirement is that some manned landers can cope with the landing slope with an inclination of 13.5 degrees. There are dozens of actual landing risk scenarios. Have StarShip considered it? The development cycle of the lander for Apollo missions is almost the same as that of the Saturn 5 rocket. Research and development funds are also very high. I can understand Blue Origin's $6 billion offer. If you use the ratio of this price to the price of SLS and the development cost of Apollo mission, you will find that it is not unreasonable. It is the quotation of SpaceX that is ridiculous.
3. For the landing of extraterrestrial objects, because of the uncertainty of the landing site, it is necessary to accurately scan the homing and switch the landing site.
At least the ability to hover for 15-30 seconds at a height of several hundred meters is required, so as to find a new landing site at a distance of several hundred meters to one or two kilometers. Falcon 9 demonstrated? This is the core work of the driver in the Apollo moon landing era.
4. Have you seen the technical verification of direct refueling and immediate launch after the landing of Falcon 9? This is the maintenance-free technology of space vehicles. The Apollo mission avoids the reuse of the engine by means of a multi-compartment structure and a special takeoff engine. Ensure the high reliability of the lander mission. There are also designs of repeated takeoff and landing landers with multiple small engines. Generally, the maximum thrust of this small engine is within a few KN, which can easily achieve maintenance-free ignition (more than 20 starts and stops) within the mission cycle.
However, for large engines like Raptor, it is very powerful to achieve 2-3 start-stop times in a task cycle, but as a reuse task, is it enough to start and stop without maintenance for 2-3 times in a task cycle? In addition, considering the problem of landing quality and the impact on various pipelines of complex rockets, it is almost inevitable for the next flight to detect them immediately after landing. In the deep space environment, it is almost impossible to maintain StarShip with such large mass and volume. Although it is impossible for other suppliers to maintain small landers within 20 tons in the field, due to its small weight, simple technology and small engine, it can start and stop many times with high reliability. In theory, its reliability is far greater than that of StarShip, a heavy carrier.
So I understand why NASA seems to be more supportive of the supplier of HLS P accessories. My bid for the HLS of SpaceX is not based on the improvement of the Dragon spacecraft and the heavy Falcon rocket, but is very confused.
Also, the hard part of both Mars and Earth atmospheric entry occurs in the air with pressure about 1:10000 of seal level, and both Earth and Mars atmospheres have such low pressure quite high above the ground (~60km on the Earth and ~40km on Mars). So yes, both planets are similar enough to use same reentry vehicle on both.
I have read some research materials. Because the density of the atmosphere on Mars is much lower than that on Earth. It is much more difficult than the earth to decelerate by using pneumatic.
In addition, you can pay attention to NASA's Mars spacecraft, from the time of each flight, and its super designed rotor. It's not difficult to judge. The aerodynamic shape design of the earth's atmosphere that can decelerate is much worse on Mars.
IOW, you have failed to demonstrate sufficient understanding of "the details of the development of modern space technology", so while you're obviously entitled to your opinion, it doesn't have much weight.
I have reservations about this statement. Generally speaking, I don't think the person who said this can really make such a judgment.
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My source of information is not confused. But the judgment process of most space enthusiasts is too hasty
This forum would appreciate a lot if you can show us what/who's this sources are
2. Generally, the lander is still possible to correct the 3-5 degree inclined surface,
But what should you do if your tilt scene is more than 5 degrees or even 10 degrees?
I have read some documents on the analysis of landing scenarios of landers, considering the existence and size of meteorite craters.
The technical requirement is that some manned landers can cope with the landing slope with an inclination of 13.5 degrees. There are dozens of actual landing risk scenarios. Have StarShip considered it?
So you imply that SpaceX people consists of all noobs who can't even calculate & engineers? Or are self-leveling legs with large stances violate the laws of physics?
The development cycle of the lander for Apollo missions is almost the same as that of the Saturn 5 rocket. Research and development funds are also very high. I can understand Blue Origin's $6 billion offer. If you use the ratio of this price to the price of SLS and the development cost of Apollo mission, you will find that it is not unreasonable. It is the quotation of SpaceX that is ridiculous.
You'll be shocked to know that self-funding the majority of development costs from contractor's own money & lander derived from launch vehicle they already developed are....doable
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This is severely misinformed. You're arguing from a mix of incredulity and misinformation.
My source of information is not confused. But the judgment process of most space enthusiasts is too hasty
You have very wrong image of how things are being developed and what is and what isn't hard. Do you know how Perseverance landed with high precision on Mars? It landed by using visual navigation, i.e. image recognition and matching to precise surface image. The technology to both know the areas without boulders larger than 20cm and how to navigate to such areas is already there in operational use. That you have no idea how it works or even its very existence doesn't make it false. Be more humble, and you'll make less confidently wrong statements.
You said that the landing process of Persevere is a link of terminal guidance and homing.
Now, almost all the automatic vertical landing processes of extraterrestrial objects have this technology.
The problem is that the range of the terminal guidance homing correction route is also very limited.
Why it is necessary to do high-precision fixed-point repeated landing similar to GPS navigation is related to the mission.
Every process in the re-entry process is very important, especially the navigation and positioning in the early and middle stages of the descent process.
In fact, this is not a very difficult technical problem for the United States. The real problem is the budget. The establishment of GPS systems for extraterrestrial objects is very important for the establishment of bases on the moon and Mars. The higher the degree of automation, the higher the precision of repetition, the more they are needed for fixed point landing. And you turn a blind eye.
The terminal guidance process (navigation process) before landing. This involves my other point of view.
NASA's Mars probe Persevere is a small lander. It is easy to correct its position during terminal guidance.
Its speed can be controlled to hover, which requires a lot of fuel reserves and enough attitude control engines. It is convenient to avoid obstacles in the air.
The landing of Falcon 9 has no near-hovering speed reduction and obstacle avoidance process. It also lacks technical means to avoid obstacles at very low speeds. StarShip is even more uncertain.
One problem you ignore is that I have repeatedly stressed that StarShip is too big and heavy. What perseverance can do is not necessarily what StarShip can do. This is why I think NASA will support the landing of a traditional lander with a capacity of less than 20 tons on the moon.
And no, ensuring that vehicle won't topple and when it would topple is not achieved by some elaborate tests with test article suspended from a special crane. It's actually trivial to simply calculate maximum safe leaning angle of the vehicle.
You know too little about hardware-in-the-loop simulation.
The physical simulation and simulation of the landing scene of an extraterrestrial planet is a very complex part with a lot of test contents, which ensures the high reliability of the mission. It is not just to calculate several dip angles. The establishment of this experimental environment costs far more money and manpower than ordinary people imagine. The period required for the experiment is also very long.
For most formal space missions, only when the physical simulation of various technologies is close to the technical maturity of 6 (the full score is 8-9) or above can the real launch mission be executed. StarShip can complete the technical prototype, but can't actually test it. Because it is too large and heavy to build a simulation experiment environment. It can only be directly verified in the actual environment outside the ground. This is a radical technology development route.
For people engaged in technology, its technical maturity is only 2 or 3. The risk is not much lower than the unmanned lunar exploration and Mars missions of the former Soviet Union. Because the former Soviet Union failed because it was in a hurry and in addition, it was to save money. If the technology maturity is not enough, the probability of failure is far greater than that of success.
I'd like to remind you that SpaceX knows how to land large and tall vehicle on an not fully stable platform. They did so over 100 times already.
You can see how different the two are by carefully comparing the landing conditions
1. The landing environment of the earth should be leveled in advance.
If the landing site is paved with cement according to the airport standard. Generally, there will also be high-strength cement with a thickness of 1-2 meters.
The surface hardness is above 10-11.
It means a rocket landing of dozens of tons (the landing mass of Falcon 9 rocket is about 20 tons), and there is no need to worry about the ground leveling problem. There is no need to worry about the undulation under the lunar soil, or the uncertain problems such as stones (you can't see under the soil layer with laser imaging). There is no need to worry about collapse.
The moon is a little better. The surface of Mars has a lot of problems. The shallow surface and the surface below contain water ice.
It looks like a flat landing site. It's not a big problem for a few hundred kg lander.
This kind of surface, a large spaceship with a total weight of one or two hundred tons, can only land on the landing leg. I dare not think about the consequences.
2. Generally, the lander is still possible to correct the 3-5 degree inclined surface,
But what should you do if your tilt scene is more than 5 degrees or even 10 degrees?
I have read some documents on the analysis of landing scenarios of landers, considering the existence and size of meteorite craters.
The technical requirement is that some manned landers can cope with the landing slope with an inclination of 13.5 degrees. There are dozens of actual landing risk scenarios. Have StarShip considered it? The development cycle of the lander for Apollo missions is almost the same as that of the Saturn 5 rocket. Research and development funds are also very high. I can understand Blue Origin's $6 billion offer. If you use the ratio of this price to the price of SLS and the development cost of Apollo mission, you will find that it is not unreasonable. It is the quotation of SpaceX that is ridiculous.
3. For the landing of extraterrestrial objects, because of the uncertainty of the landing site, it is necessary to accurately scan the homing and switch the landing site.
At least the ability to hover for 15-30 seconds at a height of several hundred meters is required, so as to find a new landing site at a distance of several hundred meters to one or two kilometers. Falcon 9 demonstrated? This is the core work of the driver in the Apollo moon landing era.
4. Have you seen the technical verification of direct refueling and immediate launch after the landing of Falcon 9? This is the maintenance-free technology of space vehicles. The Apollo mission avoids the reuse of the engine by means of a multi-compartment structure and a special takeoff engine. Ensure the high reliability of the lander mission. There are also designs of repeated takeoff and landing landers with multiple small engines. Generally, the maximum thrust of this small engine is within a few KN, which can easily achieve maintenance-free ignition (more than 20 starts and stops) within the mission cycle.
However, for large engines like Raptor, it is very powerful to achieve 2-3 start-stop times in a task cycle, but as a reuse task, is it enough to start and stop without maintenance for 2-3 times in a task cycle? In addition, considering the problem of landing quality and the impact on various pipelines of complex rockets, it is almost inevitable for the next flight to detect them immediately after landing. In the deep space environment, it is almost impossible to maintain StarShip with such large mass and volume. Although it is impossible for other suppliers to maintain small landers within 20 tons in the field, due to its small weight, simple technology and small engine, it can start and stop many times with high reliability. In theory, its reliability is far greater than that of StarShip, a heavy carrier.
So I understand why NASA seems to be more supportive of the supplier of HLS P accessories. My bid for the HLS of SpaceX is not based on the improvement of the Dragon spacecraft and the heavy Falcon rocket, but is very confused.
Also, the hard part of both Mars and Earth atmospheric entry occurs in the air with pressure about 1:10000 of seal level, and both Earth and Mars atmospheres have such low pressure quite high above the ground (~60km on the Earth and ~40km on Mars). So yes, both planets are similar enough to use same reentry vehicle on both.
I have read some research materials. Because the density of the atmosphere on Mars is much lower than that on Earth. It is much more difficult than the earth to decelerate by using pneumatic.
In addition, you can pay attention to NASA's Mars spacecraft, from the time of each flight, and its super designed rotor. It's not difficult to judge. The aerodynamic shape design of the earth's atmosphere that can decelerate is much worse on Mars.
IOW, you have failed to demonstrate sufficient understanding of "the details of the development of modern space technology", so while you're obviously entitled to your opinion, it doesn't have much weight.
I have reservations about this statement. Generally speaking, I don't think the person who said this can really make such a judgment.
GPS is very useful and once there is a similar system around the Moon or Mars, it will be very helpful. However, it is not necessary to put a GPS system in place before repeated landings to the same site can be made.
Using satellite imagery to accurately land to the same place, repeatedly, is entirely possible. Look up "Terrain Relative Navigation" -- First used to guide cruise missiles to their targets without the use of GPS or radar (both of which can be detected by anti-missile ground systems), now it has been used to land the Perseverance Rover on Mars. Landing accuracy could easily be within a few hundred meters of the target point, which is plenty sufficient for any early Moon / Mars bases.
Starship is capable of maneuvering during terminal descent using its flaps during aerodynamic phase, and with its rocket engine during the powered phase. There will likely never be a need to hover, but Starship is easily capable of hovering.
Starship is not too big and heavy, this is nonsense.
Starship will have adjustable legs that can self-level the vehicle after landing. Based on the length of the landing legs in renders we have seen, it should be capable of handling around 10 degrees of tilt. This is something that SpaceX will be working closely with NASA on, it's not something you really need to worry about.
The Moon has been mapped in great detail both visually and with laser rangefinders for altimetry. Finding a good landing site is not a problem.
Hovering is not a requirement for landing, neither on the Moon or on Mars. There should be no need to divert to another landing site kilometers away.
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One problem you ignore is that I have repeatedly stressed that StarShip is too big and heavy. What perseverance can do is not necessarily what StarShip can do. This is why I think NASA will support the landing of a traditional lander with a capacity of less than 20 tons on the moon.
1. It is "Starship", not "StarShip".
2. You keep saying that Starship is "too big and heavy", and while this is your personal opinion, it is also an unsupported assertion that SpaceX clearly disagrees with. Now, feel free to disagree with SpaceX all you want, but they have money, they have engineers, and they are building what they feel is the right vehicle. So if you want to convince people that SpaceX is wrong you're going to have get better at persuasion, otherwise you'll end up like all the other SpaceX naysayers that have wilted away after SpaceX succeeds yet again at something (this happens quite often).
3. Your opinions about what NASA will or won't do regarding their Moon efforts is off topic for this thread. Please stick to the topic at hand. NSF has moderators, and if they get called in they will "clean things up" if the conversations stray too much, so since you are new I'm giving you a heads up.
4. And actually the topic of this thread is "Why hasn't there been an "all-in-one" (same vehicle) Mars architecture before?", so this is not a thread to critique what SpaceX is doing with Starship, since the question is more related to historical reasons, business reasons, engineering reasons, etc. why the rest of the aerospace industry hasn't pursued an "all-in-one" (same vehicle) Mars architecture.
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...way too many words, largely off topic, and largely showing at best superficial understanding of the matters and frequently totally wrong...
You're wrong way too many times to give your claims much (if any) credit.
The visual navigation system used by Perseverance is not present on "almost all the automatic vertical landing processes of extraterrestrial objects", it was present on only one system: Perseverance. This clearly demonstrates you have no clue what you're talking about.
It's also obvious you understand precious little about hardware in a loop testing. The image of it you're presenting is simply ridiculous.
Generally the following statement of yours: Generally, the lander is still possible to correct the 3-5 degree inclined surface
is severely wrong. It's about 3x off.
And so on.
You have to accept the reality that your intuitions are not facts. You make a lot of unsupported claims.
PS.
Also, you have been reminded several times to stay on topic. You're new on this forum, so you should exercise the common courtesy to read ad understand the community rules here. That's pretty basic ask, so please do so, and post relevant things in relevant topics.
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fascinating, but why hasn't there been an "all-in-one" (same vehicle) Mars architecture before?
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fascinating, but why hasn't there been an "all-in-one" (same vehicle) Mars architecture before?
Nobody thought of it until a certian senator from alabama had NASA's budget in a controlling grapple, and an all-in-one lander didnt bring jobs to alabama.
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fascinating, but why hasn't there been an "all-in-one" (same vehicle) Mars architecture before?
My personal hypothesis, based on other rocket development paradigm - premature optimization for mass.
If you start your design as mass-constrained (includes propellants!), it makes sense to have hyper-specialized, hyper-optimized-for-the-job separate elements.
If, on the other hand, you approach it with mass-is-cheap (prop depots, isru), you can "afford" to "waste" mass and optimize for cost.
Remember the you-are-wasting-payload-for-recovery/your-rocket-is-too-big-for-the-payload critiques of F9R? (The dial-a-rocket crowd).
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I think a big part of it is a stubborn refusal to pursue in-orbit refueling.
NASA's conceptual design process is also not much different than, say, Kerbal Space Program... in the sense that mass growth is often assumed such that dry mass ratios will be fairly high (like in KSP), requiring a lot of staging off of elements. NASA's conceptual assumptions for in-space stages are like far worse in dry mass than what is in principle possible and also what industry actually does achieve when they attempt to optimize. That means lots and lots of staging (which is actually part of the fun of KSP... and NASA, in a sense, in that there are a bunch of elements that can be spread to lots of different contractors in lots of different states).
A lot of NASA's conceptual designs are pre-ISS. ISS demonstrated regular autonomous rendezvous and docking. Before ISS, the idea among many in NASA was that more than a couple launches would be crazy, and that the spacecraft that is doing the docking would need to be crewed. Space Station Freedom was therefore a kind of staging point for deep space missions. ISS has had literally hundreds of flights to it; less than half have been crewed, and with Dragon, NASA finally had an autonomous rendezvous and docking capability demonstrated.
In the before ISS and after Apollo days, the assumption is you'd be building up pieces of an interplanetary mission in modular units launched on an RLV, and you'd put them together to make a large interplanetary vessel.
I'm not really sure why refueling wasn't as common in architectures. With refueling, your 5 or 10 launch mission can still have most of its dry mass launched in one go, the vast majority of the rest are just fueling flights. Maybe it was a sort of infatuation with drop tanks? Before Shuttle, it just seemed like an obvious way to reduce costs... don't need to bring tank mass with you, and tanks were just tanks and so therefore "cheap"... But... The Shuttle External tank ended up costing like $150 million apiece by the end of the program. Not at all cheap.
I suppose hydrogen tends to push you in this direction due to its very low density.
Also, Shuttle could not land on the Moon or Mars due to being horizontal landing, like an airplane. Most RLV concepts I think used that approach (X-33/VentureStar, Skylon, etc). The DC-X style approach was not favored by NASA, but does lend itself to all-in-one Mars architectures as you can use it as a lander (on Mars or on Earth or on the Moon).
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Also, Shuttle could not land on the Moon or Mars due to being horizontal landing, like an airplane. Most RLV concepts I think used that approach (X-33/VentureStar, Skylon, etc). The DC-X style approach was not favored by NASA, but does lend itself to all-in-one Mars architectures as you can use it as a lander (on Mars or on Earth or on the Moon).
Any spaceplane is not designed for landing on Mars, just for making a horizontal landing back to Earth runways. The design bureau of Vladimir Chelomei envisaged the UR-900 and the UR-700M nuclear-powered variant of the UR-700 for carrying humans to Mars, and the MK-700 spacecraft designed to carried by the UR-900 and UR-700M would have comprised the VA re-entry capsule, a living/equipment module that was to be the the living quarters for the crew, and a Mars lander. There was a plan to launch the Mars 4NM and 5NM aboard the N1 and have those missions deploy the heavy Marsokhod rovers, but when the N1 program was canceled in 1974, so were the Mars 4NM and 5NM missions. Therefore, the N1 and super-heavy rocket designs envisaged by Chelomei utilized somewhat distinctive Mars mission architectures.
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Also, Shuttle could not land on the Moon or Mars due to being horizontal landing, like an airplane. Most RLV concepts I think used that approach (X-33/VentureStar, Skylon, etc). The DC-X style approach was not favored by NASA, but does lend itself to all-in-one Mars architectures as you can use it as a lander (on Mars or on Earth or on the Moon).
Any spaceplane is not designed for landing on Mars, just for making a horizontal landing back to Earth runways....
That's my point. There were concepts for DC-X/DeltaClipper to do lunar/martian landings. Starship, too, of course. But not for spaceplanes (once we learned how thin its atmosphere really is).
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fascinating, but why hasn't there been an "all-in-one" (same vehicle) Mars architecture before?
Nobody thought of it until a certian senator from alabama had NASA's budget in a controlling grapple, and an all-in-one lander didnt bring jobs to alabama.
I suspect Slarty was dryly commenting on the off-topic nature of much of the recent discussion, rather than actually wanting an answer.
That said, in my view the answer is simply that there hasn't been a mission requirement that needed it before. Now there is: cheap mass transport between the planets to enable a city of a million on Mars. That mission leads to a requirement for a large, refuel-able, reusable two-way transport system, then add in the benefits of aerobraking at both ends and an all-in-one solution (plus a reusable booster for Earth launch) is the result.
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There have been lots of paper architectures with varying-degrees-of-unitary (e.g. is a vehicle assembled in Earth orbit from multiple component launches but not further staged for Mars departure and return an 'all in one' vehicle?) architectures proposed, and some maybe even studies with moderate funds.
There have been none previously pursued to the point of actual manufacture, because the funding for such an endeavour is immense, and until the last decade the sole purview of public funded efforts. And public funding adds additional design constraints to CONOPS beyond the purely technical (and has since the dawn of rocketry), generally precluding such architectures. The second* most common constraints being the requirement to utilise existing vehicles, existing ground infrastructure, and/or existing components, rather than design tabula-rasa.
*The most common being "your design needs $X? You have have $X/2".
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Also, Shuttle could not land on the Moon or Mars due to being horizontal landing, like an airplane. Most RLV concepts I think used that approach (X-33/VentureStar, Skylon, etc). The DC-X style approach was not favored by NASA, but does lend itself to all-in-one Mars architectures as you can use it as a lander (on Mars or on Earth or on the Moon).
Any spaceplane is not designed for landing on Mars, just for making a horizontal landing back to Earth runways....
That's my point. There were concepts for DC-X/DeltaClipper to do lunar/martian landings. Starship, too, of course. But not for spaceplanes (once we learned how thin its atmosphere really is).
The mode of landing for the DC-X is probably the big reason that Lockheed Martin was declared the winner of the Reusable Launch Vehicle (RLV) competition by NASA, given the risk of a DC-X unintentionally making a hard vertical landing on an earthbound surface after returning from space.
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That’s the airplane bias showing. Falcon just demonstrated its 100th successful consecutive booster landing. This is better reliability than any of us would have anticipated, given that there is zero engine redundancy allocated for it and there are 9 engines that have to work basically flawlessly (underperformance on the way up is made up with margin that comes out of the landing propellant). (A crewed vehicle like Starship… or Delta-Clipper I’d imagine… would include engine redundancy for landing and sufficient propellant margins to account for engine-out, etc.)
Considering that glider returns, like Dreamchaser’s or SpaceShipTwo’s, don’t have a perfect record… I would consider this vindication that powered landing can be just as reliable as winged landing. Or parachute, for that matter, considering the failure that occurred for Soyuz and Apollo.
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I think the real reason is that no one who has presented a serious attempt at a Mars plan has ever had to work within Elon's financial constraints. SpaceX has to work with as much commonality as possible because that required a minimum of resources to design and build.
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Yes, SpaceX has only really developed two basic rocket engines. The Merlin and the Merlin Vacuum for 2nd stage, and the Raptor and the Raptor Vacuum for the second stage/Starship. The engines are the most expensive part of a rocket system. So SpaceX had only developed two basic engines. Tanking and computer controls are not as expensive. Their system for going to Mars is about the least expensive architecture they could do. Nuclear engines have a lot of red tape and problems securing nuclear material. Some type of refueling will have to be done on most all architectures. They also have learned how to land rockets.
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Going back to the OP, I wonder whether SpaceX's high degree of vertical integration and Musk's role as CTO might have something to do with it. When a vehicle is built by multiple organizations, it's important to keep the interfaces between them and their products simple. As an example, during Apollo, as a general rule, electrical power was not to flow through interfaces: each module powered itself. The Saturn launch vehicle and the Apollo spacecraft had their own guidance systems (which proved crucial on Apollo 12). An outfit like NASA is politically constrained to share the work among multiple prime contractors with disparate styles, competencies and philosophies. Having them all work together on a monolithic universal vehicle would be a managerial nightmare.
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Going back to the OP, I wonder whether SpaceX's high degree of vertical integration and Musk's role as CTO might have something to do with it. When a vehicle is built by multiple organizations, it's important to keep the interfaces between them and their products simple. As an example, during Apollo, as a general rule, electrical power was not to flow through interfaces: each module powered itself. The Saturn launch vehicle and the Apollo spacecraft had their own guidance systems (which proved crucial on Apollo 12). An outfit like NASA is politically constrained to share the work among multiple prime contractors with disparate styles, competencies and philosophies. Having them all work together on a monolithic universal vehicle would be a managerial nightmare.
Excellent points.
Also, the physics of orbital rocket flight using chemical propulsion strongly suggests a staging approach. Also the physics of reentry makes reuse a very, very difficult problem.
With those constraints, along with an Apollo mandated of "waste anything but time", adopting a design philosophy of expendable staging was reasonable in the 1960s.
Adopting brand new, entirely different fundamental design constraints and goals will lead to different results.
A useful, different goal could be: "Design to minimize long term operational costs". That directly leads to reusability, high flight rate, commonality of engines.
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I think the desire to reduce staging pushed everyone too hard toward SSTO since the very dawn of the space age. Especially for RLVs, SSTO is just too inefficient. 2STO is only a small increase in complexity but is just a MASSIVE improvement in margins all over the place. Maybe 4 or 5 stages is bad, but 2 stages can be done relatively easily and can be done with reuse as well.
Falcon 9 has really vindicated 2STO as operationally efficient and reliable. The slight complication of stage integration is no big deal.
So I think that’s part of it. And a VTVL reusable upper stage really sets the stage for an”all in one” architecture.
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I think the desire to reduce staging pushed everyone too hard toward SSTO since the very dawn of the space age. Especially for RLVs, SSTO is just too inefficient. 2STO is only a small increase in complexity but is just a MASSIVE improvement in margins all over the place. Maybe 4 or 5 stages is bad, but 2 stages can be done relatively easily and can be done with reuse as well.
Falcon 9 has really vindicated 2STO as operationally efficient and reliable. The slight complication of stage integration is no big deal.
So I think that’s part of it. And a VTVL reusable upper stage really sets the stage for an”all in one” architecture.
The way I like to think of it is that 2STO is the minimum that can (currently) launch a practical amount of fuel into orbit, and orbital refuelling then makes additional stages redundant for all but the most extreme cases.
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That’s pretty good. But I think I’d emphasize that people shouldn’t think SSTO RLVs are impossible, either, just insanely inefficient and fragile. When 80% of your mass in orbit is your launch vehicle’s dry mass (that then ALL has to go through reentry), that’s kinda bad. Even typical aviation’s 50-60% is higher than you’d like. Staging allows the final orbit mass to only have 20-40% of the mass in orbit as parasitic vehicle dry mass, vast majority can be payload.
That means for the same vehicle manufacturing cost and same fuel costs and refurb costs, you can get like 4 times the payload. 2STO is just so obvious from that perspective.
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That’s pretty good. But I think I’d emphasize that people shouldn’t think SSTO RLVs are impossible, either, just insanely inefficient and fragile. When 80% of your mass in orbit is your launch vehicle’s dry mass (that then ALL has to go through reentry), that’s kinda bad. Even typical aviation’s 50-60% is higher than you’d like. Staging allows the final orbit mass to only have 20-40% of the mass in orbit as parasitic vehicle dry mass, vast majority can be payload.
That means for the same vehicle manufacturing cost and same fuel costs and refurb costs, you can get like 4 times the payload. 2STO is just so obvious from that perspective.
Why would the vehicle manufacturing and fuel/refurb costs be the same for 2 stages as one? Not that it matters much, because it will be less than 4 times as much so you win anyway.
Also, are both F9+Dragon and Starship considered two-stage-to-orbit? Because it feels like F9+Dragon has an extra stage in there compared to Starship when looking at the full mission.
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Also, are both F9+Dragon and Starship considered two-stage-to-orbit? Because it feels like F9+Dragon has an extra stage in there compared to Starship when looking at the full mission.
By that logic add an extra stage to every nearly every payload in existence, since almost all have maneuvering thrusters (such as Starlink, which gets to its final orbit on its own).
Come to think of it, in KSP, that is pretty much true.
So rather than going down that path, since 1 orbit counts as an "to orbit" per Yuri Gagarin tradition, no, the Dragon doesn't count as a stage in the "to-orbit" category, and neither does Starlink or the thousands of spacecraft out there.
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Also, are both F9+Dragon and Starship considered two-stage-to-orbit? Because it feels like F9+Dragon has an extra stage in there compared to Starship when looking at the full mission.
By that logic add an extra stage to every nearly every payload in existence, since almost all have maneuvering thrusters (such as Starlink, which gets to its final orbit on its own).
Come to think of it, in KSP, that is pretty much true.
So rather than going down that path, since 1 orbit counts as an "to orbit" per Yuri Gagarin tradition, no, the Dragon doesn't count as a stage in the "to-orbit" category, and neither does Starlink or the thousands of spacecraft out there.
I consider it a grey area. By your definition, the OMS thrusters and the orbiter itself acts as like a second or third stage for Shuttle flights.
A capsule or payload which does an insertion burn to get to a stable orbit could be considered an upper stage.
The difference between Starship upper stage and Dragon is… well, a difference in degree. Dragon has a lot less on-board delta-v but in principle it could have more.
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Also, are both F9+Dragon and Starship considered two-stage-to-orbit? Because it feels like F9+Dragon has an extra stage in there compared to Starship when looking at the full mission.
By that logic add an extra stage to every nearly every payload in existence, since almost all have maneuvering thrusters (such as Starlink, which gets to its final orbit on its own).
Come to think of it, in KSP, that is pretty much true.
So rather than going down that path, since 1 orbit counts as an "to orbit" per Yuri Gagarin tradition, no, the Dragon doesn't count as a stage in the "to-orbit" category, and neither does Starlink or the thousands of spacecraft out there.
I consider it a grey area. By your definition, the OMS thrusters and the orbiter itself acts as like a second or third stage for Shuttle flights.
A capsule or payload which does an insertion burn to get to a stable orbit could be considered an upper stage.
The difference between Starship upper stage and Dragon is… well, a difference in degree. Dragon has a lot less on-board delta-v but in principle it could have more.
Yeah, a grey area for sure: SpaceX seems to have a knack for finding them.
It just feels like there is a difference between a 2nd stage that launches a spaceship and a 2nd stage that is a spaceship.
Other ways to look at it...
The Dragon spaceship needs 2 additional stages to get it into orbit, Starship only needs one. But we're calling both "2 stage to orbit".
Or if you magically evolved Dragon and the F9 first stage to the point that you no longer needed the F9 second stage, what would you call that? You've removed a stage from your 2STO but it clearly isn't an SSTO.
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Yep - a degree.
A Star-48 has been counted as a 3rd stage of Atlas-V launching the New Horizons probe. Yet, we say that Atlas V is a 2 stage rocket.
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The Dragon spaceship needs 2 additional stages to get it into orbit, Starship only needs one. But we're calling both "2 stage to orbit".
Or if you magically evolved Dragon and the F9 first stage to the point that you no longer needed the F9 second stage, what would you call that? You've removed a stage from your 2STO but it clearly isn't an SSTO.
You are confused because you using the wrong terms. "to orbit" means whatever you want it to mean, no more no less (to paraphrase Carroll).
"to-orbit" implies "to a LEO of at least one orbit". If not, then Yuri Gagarin isn't the first. And thus Dragon is 2 stages to orbit. QED.
"to space station rendezvous", Dragon is indeed a 3 stage system. As is Starlink a "3 stages to final orbit" system.
Starship, OTOH, is 2-stage-to-space-station-rendezvous, and also to the rest of the Solar system with refueling.
Kinda. because refueling is equivalent to staging in terms of the rocket equation. (Jupiter requires 2 refuelings of the final stage. Is that 4 stages to Jupiter?).
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The Dragon spaceship needs 2 additional stages to get it into orbit, Starship only needs one. But we're calling both "2 stage to orbit".
Or if you magically evolved Dragon and the F9 first stage to the point that you no longer needed the F9 second stage, what would you call that? You've removed a stage from your 2STO but it clearly isn't an SSTO.
You are confused because you using the wrong terms. "to orbit" means whatever you want it to mean, no more no less (to paraphrase Carroll).
"to-orbit" implies "to a LEO of at least one orbit". If not, then Yuri Gagarin isn't the first. And thus Dragon is 2 stages to orbit. QED.
"to space station rendezvous", Dragon is indeed a 3 stage system. As is Starlink a "3 stages to final orbit" system.
Starship, OTOH, is 2-stage-to-space-station-rendezvous, and also to the rest of the Solar system with refueling.
Kinda. because refueling is equivalent to staging in terms of the rocket equation. (Jupiter requires 2 refuelings of the final stage. Is that 4 stages to Jupiter?).
Doesn't staging requires stages in the sense of separate platforms? Orbital refueling wouldn't be staging by that definition, perhaps range extension. I guess stage 1, stage 2, stage 3 in the sense of a series of steps in an operation is another use of the word so perhaps both are correct? Although the second definition is pretty arbitrary and could include refueling or any number of steps depending on the operations.
Starship would be a TSTO, and then, operationally, become an OTV (Orbital transfer vehicle) with Interplanetary capabilities using refueling. Once it reaches Mars it turns into a Re-entry Vehicle. On Mars, once landed, it becomes a SSTO and Interplanetary OTV combo, and back at Earth it's a Re-entry vehicle again.
Due to the fact that Mars has an atmosphere, the OTV to Mars is significantly optimized using the tiles for the Re-entry Vehicle for aerobraking. Same advantage for Earth return. This would only be true for fast transits using aerobraking. I guess there is not much gain for Hohmann transfer orbits. This optimization does not exist for the airless Moon, making Starship a less interesting platform for that destination.
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I would consider orbital refueling to do the same kind of job as another stage. It’s a very useful analogue.
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The Dragon spaceship needs 2 additional stages to get it into orbit, Starship only needs one. But we're calling both "2 stage to orbit".
Or if you magically evolved Dragon and the F9 first stage to the point that you no longer needed the F9 second stage, what would you call that? You've removed a stage from your 2STO but it clearly isn't an SSTO.
You are confused because you using the wrong terms. "to orbit" means whatever you want it to mean, no more no less (to paraphrase Carroll).
"to-orbit" implies "to a LEO of at least one orbit". If not, then Yuri Gagarin isn't the first. And thus Dragon is 2 stages to orbit. QED.
"to space station rendezvous", Dragon is indeed a 3 stage system. As is Starlink a "3 stages to final orbit" system.
Starship, OTOH, is 2-stage-to-space-station-rendezvous, and also to the rest of the Solar system with refueling.
Kinda. because refueling is equivalent to staging in terms of the rocket equation. (Jupiter requires 2 refuelings of the final stage. Is that 4 stages to Jupiter?).
Doesn't staging requires stages in the sense of separate platforms? Orbital refueling wouldn't be staging by that definition, perhaps range extension. I guess stage 1, stage 2, stage 3 in the sense of a series of steps in an operation is another use of the word so perhaps both are correct? Although the second definition is pretty arbitrary and could include refueling or any number of steps depending on the operations.
Starship would be a TSTO, and then, operationally, become an OTV (Orbital transfer vehicle) with Interplanetary capabilities using refueling. Once it reaches Mars it turns into a Re-entry Vehicle. On Mars, once landed, it becomes a SSTO and Interplanetary OTV combo, and back at Earth it's a Re-entry vehicle again.
Due to the fact that Mars has an atmosphere, the OTV to Mars is significantly optimized using the tiles for the Re-entry Vehicle for aerobraking. Same advantage for Earth return. This would only be true for fast transits using aerobraking. I guess there is not much gain for Hohmann transfer orbits. This optimization does not exist for the airless Moon, making Starship a less interesting platform for that destination.
Staging means at least two different things:
1. Removing old vehicle and continuing voyage in a new, smaller vehicle.
2. Taking advantage of the rocket equation by effectively starting over with a new mass ratio
Traditional rockets do both. Hence some of the confusion.
Starship does both for one stage change, which gets it to LEO. Then it uses refueling which is only #2. Which means Jupiter (and Moon) is effectively 4 stages, and Mars as 3 stages, but by traditional definition (#1) is only 2 stages.
Starlink and Dragon are 3 stages by both definitions, but two are used to get to initial orbit, and the third to get to final orbit.
See? Very clear ;) ;D
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...way too many words, largely off topic, and largely showing at best superficial understanding of the matters and frequently totally wrong...
You're wrong way too many times to give your claims much (if any) credit.
The visual navigation system used by Perseverance is not present on "almost all the automatic vertical landing processes of extraterrestrial objects", it was present on only one system: Perseverance. This clearly demonstrates you have no clue what you're talking about.
It's also obvious you understand precious little about hardware in a loop testing. The image of it you're presenting is simply ridiculous.
Generally the following statement of yours: Generally, the lander is still possible to correct the 3-5 degree inclined surface
is severely wrong. It's about 3x off.
And so on.
You have to accept the reality that your intuitions are not facts. You make a lot of unsupported claims.
PS.
Also, you have been reminded several times to stay on topic. You're new on this forum, so you should exercise the common courtesy to read ad understand the community rules here. That's pretty basic ask, so please do so, and post relevant things in relevant topics.
The automatic landing system for extraterrestrial objects I mentioned does not include some ancient landing methods for the moon and planets in the early Soviet Union and the United States.
Currently, in addition to the US-based Persevere series you mentioned, only Chang'e 3,4,5 and Tianwen 1 have used visual imaging technology to assist in terminal guidance landing and achieved success.
As for dealing with landing on a larger slope without tipping over, the figures quoted above are incorrect in my memory.
However, please pay attention to the height of the lander and the detailed design of the landing leg. I have seen various landing leg system design materials. It's more than 3-5 degrees. The problem is the design of this type of landing leg system. The overall shape of the lander is low, and the height to span ratio is within 2:1, even lower than 1:1. Lowered the center of gravity of the lander. The ratio of height to span of the StarShip lander appears to be greater than 3:1
Finally, I hope you understand.
Some of my views only illustrate my interpretation of some phenomena.
For example, I think NASA has little interest in landing large landers like StarShip on extraterrestrial objects. This can be seen in many details.
For example, in the PDF of the latest portal space station, although the text mentions StarShip. However, in various official images, there are no images of StarShip docking with the space station. I didn't just notice this, and many people have already discovered it.
The other is in the accompanying picture of the latest Artemis plan. After 2028, HLS is clearly not the HLS version of StarShip.
I think these phenomena all represent some problems.
I just want you to think calmly. Is the configuration design of StarShip really the best plan for landing on the moon or on fire? Why do I support the consumptive upper level? The reason is that it can better match most of the achievements and solutions of current aerospace technology.
Currently, StarShip does not have the ability to truly release large scientific loads in outer space. Currently, StarShip's design does not have a large hatch, and it is uncertain when it will be resolved, which is completely unable to replace the role of SLS. StarShip's hatch design, handling large sized loads on the ground, is also a problem at present. It is replaced by a consumable upper level. "At present, all the problems are gone, and many of SLS's work can be replaced immediately.". Opening a new era of aerospace.
I'm not saying that StarShip's design for deep space is definitely not feasible, but I want to ask, is this really the best and most suitable choice in the short term?
Many times, I have different views on some issues, especially when I know the design thinking of other heavy rockets. When comparing the design differences between the two rockets, many differences worth considering can be found. I also agree with you and do not want to discuss this topic further, lest it cause unnecessary controversy.
I think it may take 5-10 years, or even longer, to continuously observe and obtain the correct answer.
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That’s the airplane bias showing. Falcon just demonstrated its 100th successful consecutive booster landing. This is better reliability than any of us would have anticipated, given that there is zero engine redundancy allocated for it and there are 9 engines that have to work basically flawlessly (underperformance on the way up is made up with margin that comes out of the landing propellant). (A crewed vehicle like Starship… or Delta-Clipper I’d imagine… would include engine redundancy for landing and sufficient propellant margins to account for engine-out, etc.)
Considering that glider returns, like Dreamchaser’s or SpaceShipTwo’s, don’t have a perfect record… I would consider this vindication that powered landing can be just as reliable as winged landing. Or parachute, for that matter, considering the failure that occurred for Soyuz and Apollo.
Years ago I made a series of spreadsheets modeling failure rates for launch and booster recovery attempting to estimate cost savings from re-use. I never modeled 100 of 100 booster recoveries, too unrealistic. I was WRONG.
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Currently, StarShip does not have the ability to truly release large scientific loads in outer space. Currently, StarShip's design does not have a large hatch, and it is uncertain when it will be resolved, which is completely unable to replace the role of SLS. StarShip's hatch design, handling large sized loads on the ground, is also a problem at present. It is replaced by a consumable upper level. "At present, all the problems are gone, and many of SLS's work can be replaced immediately.". Opening a new era of aerospace.
I'm not saying that StarShip's design for deep space is definitely not feasible, but I want to ask, is this really the best and most suitable choice in the short term?
Do you really think it will take longer for SpaceX to build a large hatch or openable fairing for Starship than it will to build a spare SLS that is not already committed to Artemis so it could launch some other satellite? Right now I believe every SLS that can be built in the next 10 years is committed to Artemis, and Boeing has said they would need a lot more money to increase the build rate. Meanwhile, SpaceX has reused more fairings on the F9 than most companies have ever built, and built more Starship variants in the last 9 months than SLS will have in the next 5 years.
What is a better choice short term, given SLS is just not available?
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SLS ALSO doesn’t have a fairing, and the cost of developing one would not be trivial, especially a large one. SpaceX has at least made prototype openable fairings for Starship.
I will never understand people who think SLS is ahead of Starship for scientific payloads because of a PowerPoint for a fairing they saw, which isn’t even funded. We’ve actually seen Starship fairing prototypes.
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For example, I think NASA has little interest in landing large landers like StarShip on extraterrestrial objects. This can be seen in many details.
For example, in the PDF of the latest portal space station, although the text mentions StarShip. However, in various official images, there are no images of StarShip docking with the space station. I didn't just notice this, and many people have already discovered it.
This is ridiculous. The fact is Starship is the contracted vehicle for Artemis. In fact the only contracted vehicle.
The other is in the accompanying picture of the latest Artemis plan. After 2028, HLS is clearly not the HLS version of StarShip.
Again, you're plain wrong. The plan is to have both Starship and some other not yet selected lander, the same way Commercial Crew is supposed to fly on SpaceX Crew Dragon and Boeing Starliner CST-100. The only issue is Dragon has flown 1 crewed test and 6 operational NASA missions (and 2 non-NASA missions) while CST-100 didn't even do the crewed test flight. But the plan is to alternate Crew Dragon and Starliner CST-100 once the other one is ready.
The plan for HLS is similar: fly Artemis III and Artemis IV on Starship and then hopefully alternate Starship with whatever other lander wins the contract.
I'm basing my information on actual released NASA documents and statements and not few artist vision pictures.
I think these phenomena all represent some problems.
I think you're using nonsesical sources. Garbage in -> garbage out.
I just want you to think calmly. Is the configuration design of StarShip really the best plan for landing on the moon or on fire? Why do I support the consumptive upper level? The reason is that it can better match most of the achievements and solutions of current aerospace technology.
You have conclusively demonstrated that you don't have any appreciable understanding of current aerospace technology. So you can think whatever you want, but it doesn't make it correct or informed.
Anyway, Starship doesn't have to be the best plan. It just is the only workable plan before 2030.
Currently, StarShip does not have the ability to truly release large scientific loads in outer space. Currently, StarShip's design does not have a large hatch, and it is uncertain when it will be resolved, which is completely unable to replace the role of SLS. StarShip's hatch design, handling large sized loads on the ground, is also a problem at present. It is replaced by a consumable upper level. "At present, all the problems are gone, and many of SLS's work can be replaced immediately.".
Opening a new era of aerospace.
SLS doesn't have any fairing. None at all. It has no role of launching any scientific payload. SLS can only launch Orion. That's it. SLS has no fairings, no chosen place to manufacture them, no tooling to build them... Nothing.
Contrary to SLS Starship does have multiple physical test articles of its fairing.
I'm not saying that StarShip's design for deep space is definitely not feasible, but I want to ask, is this really the best and most suitable choice in the short term?
It's workable and has workable budget. And is designed for frequent use and streamlined processing, this means its operating costs will also be reasonable. Contrary to other super heavy rockets which either had totally unworkable budgets (Ares, got cancelled) or borderline workable budget allowing them to fly once per couple of years (SLS).