I have to admit, I am concerned with the nearly unlimited roles people are proscribing to Starship. Each variant would have to be tested extensively and you introduce a whole gambit of failure modes.Isn't that what doomed Space Shuttle trying to accomplish too many roles?
Quote from: Khadgars on 05/11/2021 02:58 pmI have to admit, I am concerned with the nearly unlimited roles people are proscribing to Starship. Each variant would have to be tested extensively and you introduce a whole gambit of failure modes.Isn't that what doomed Space Shuttle trying to accomplish too many roles?The big thing is orbital refueling. If the Saturn 5 had orbital refueling, Saturn-Skylab could have done almost everything Starship is planned to do. Starship is just a bit more specialized for Mars, has more advanced engines, and is designed to be both affordable and reusable, making a lot of things it's kinda overbuilt for, worth doing anyway.
Quote from: rakaydos on 05/11/2021 03:57 pmQuote from: Khadgars on 05/11/2021 02:58 pmI have to admit, I am concerned with the nearly unlimited roles people are proscribing to Starship. Each variant would have to be tested extensively and you introduce a whole gambit of failure modes.Isn't that what doomed Space Shuttle trying to accomplish too many roles?The big thing is orbital refueling. If the Saturn 5 had orbital refueling, Saturn-Skylab could have done almost everything Starship is planned to do. Starship is just a bit more specialized for Mars, has more advanced engines, and is designed to be both affordable and reusable, making a lot of things it's kinda overbuilt for, worth doing anyway. Other than reusability and engines what else does Starship have that make it specialized to Mars and not, say the Moon?
I know of crew starship, tanker, cargo, lunar lander and maybe a deep space version (which is just a completely stripped down version, so very simple and very cheap).I see no reason why SpaceX would be unable to follow through with these.
Quote from: electricdawn on 05/11/2021 03:01 pmI know of crew starship, tanker, cargo, lunar lander and maybe a deep space version (which is just a completely stripped down version, so very simple and very cheap).I see no reason why SpaceX would be unable to follow through with these.Starship (mixed crew/cargo or the 'standard' Starship), Tanker and Cargo. The "Lunar lander" makes zero sense for SpaceX to build as it would be a vastly inferior vehicle, and wasted effort when they could just 'sell' flights on a regular Starship. A 'deep space' version also doesn't make much sense given SpaceX's goals and ambitions. It significantly detracts from using the "basic 3" Starships for any and all missions and thereby supporting the economics of Starship.
Quote from: RanulfC on 05/11/2021 04:02 pmQuote from: electricdawn on 05/11/2021 03:01 pmI know of crew starship, tanker, cargo, lunar lander and maybe a deep space version (which is just a completely stripped down version, so very simple and very cheap).I see no reason why SpaceX would be unable to follow through with these.Starship (mixed crew/cargo or the 'standard' Starship), Tanker and Cargo. The "Lunar lander" makes zero sense for SpaceX to build as it would be a vastly inferior vehicle, and wasted effort when they could just 'sell' flights on a regular Starship. A 'deep space' version also doesn't make much sense given SpaceX's goals and ambitions. It significantly detracts from using the "basic 3" Starships for any and all missions and thereby supporting the economics of Starship.Elon: "You're right. Everything we wanted the falcon heavy to do, the Falcon 9 can do. Lets just cut our losses and cancel it."Gwynn: "You cant cancel it, we have contracts!"
Uhm... Lunar Starship is required for the HLS contract? And I can also see a use as a pioneer Starship that lands on planets where there is no infrastructure and creates this infrastructure (ISRU, landing pad) for "regular" Starships to use.So, IMHO, this is a necessary step for Musk's dreams about Mars. At least IMHO.
Quote from: rakaydos on 05/11/2021 04:06 pmQuote from: RanulfC on 05/11/2021 04:02 pmQuote from: electricdawn on 05/11/2021 03:01 pmI know of crew starship, tanker, cargo, lunar lander and maybe a deep space version (which is just a completely stripped down version, so very simple and very cheap).I see no reason why SpaceX would be unable to follow through with these.Starship (mixed crew/cargo or the 'standard' Starship), Tanker and Cargo. The "Lunar lander" makes zero sense for SpaceX to build as it would be a vastly inferior vehicle, and wasted effort when they could just 'sell' flights on a regular Starship. A 'deep space' version also doesn't make much sense given SpaceX's goals and ambitions. It significantly detracts from using the "basic 3" Starships for any and all missions and thereby supporting the economics of Starship.Elon: "You're right. Everything we wanted the falcon heavy to do, the Falcon 9 can do. Lets just cut our losses and cancel it."Gwynn: "You cant cancel it, we have contracts!"Just going to ignore the little fact that Falcon Heavy was not less capable than Falcon 9 then? And specifically that it COULD do more than the Falcon 9 which Lunar Starship can't? You are literally trying to use a totally different situation to illustrate a point that doesn't exist. A "better", or at least more applicable argument would be that SpaceX up and decided to abandon the Falcon 9/Dragon for an as of yet un-flown "Heavy Falcon" with a totally reusable Super-Dragon upper stage and then accepted development funding towards that LV with the stipulation that it would have an expendable upper stage that was based on the reusable design. You still have to design and develop the booster(s) and upper-stage as a prerequisite to deploying the system and meanwhile you can work on the customers 'requirement' that it be expendable and single use. There is literally NO conflict here.As for contracts, well see below...Quote from: electricdawn on 05/11/2021 04:14 pmUhm... Lunar Starship is required for the HLS contract? And I can also see a use as a pioneer Starship that lands on planets where there is no infrastructure and creates this infrastructure (ISRU, landing pad) for "regular" Starships to use.So, IMHO, this is a necessary step for Musk's dreams about Mars. At least IMHO."Development" of the suggested Lunar Starship is part of the HLS contract, let me repeat, you need a "Starship" to develop the "Lunar Starship" there is literally no conflict at this point as ANY development of Starship itself can be shown to be progress towards Lunar Starship. The only point where 'contractual' issues might be brought up is if by 2024 SpaceX has yet to fly a Starshp of any kind to orbit. (Possible) At which point questions may be asked but we've been here before and the 'answer' is going to be the same, keep slogging forward, especially if there is no 'alternative' available.Once SpaceX has a "Starship" on orbit they can demonstrate on-orbit propellant transfer and at that point it is pretty much a "Lunar Starship". Unless NASA wants to demand that it be expendable and of limited utility at which point SpaceX has the choice of agreeing to build a couple "one-off-really-bad-Starships" or making the argument that Starship itself fulfills the "Lunar Starship" requirements. (Which btw was their initial argument for proposing Starship for HLS)I'd tend to agree with you about the utility of an 'expendable' Starship that could be broken apart at the destination to provide the nexus of an outpost but that's not really something that SpaceX has embraced. They would much rather than reusable Starships than one-off designs and frankly given their proposed 'economics' expendable doesn't make all that much sense. Yes this is VERY much a 'necessary' step in Musk's plans. With government money he can greatly advance his efforts towards getting Starship/Superheavy operational and the 'government' now has a lot more incentive to clear any obstacles in the "way" of that effort.If you have no issues with a government supported, unbreakable launch monopoly run by one person JUST because they say they want to get people to Mars "real soon now" then this is obviously going to sound like paradise. Those of us who know out history, have a healthy skepticism of a certain CEO due to his past and current activities and therefore have doubts about his 'altruism' and stated long-range plans have some well grounded reasons for pointing out the issues involved.And lastly let me point out that reuse of at least SOME parts of the HLS is implicit in the requirements as every design incorporated it to some extent. The Lunar Starship is to be 'reusable' if you can get it to the Gateway or somewhere it can be refilled with propellant. The ONLY difference is that "Lunar Starship" is not "planned" to be 'returnable' to Earth for reuse whereas Starship is. Again, feel free to try and point out a REAL conflict here Randy
Quote from: electricdawn on 05/11/2021 03:01 pmI know of crew starship, tanker, cargo, lunar lander and maybe a deep space version (which is just a completely stripped down version, so very simple and very cheap).I see no reason why SpaceX would be unable to follow through with these.I think we are quite a ways away from understanding exactly what Starship will require in-order to land on Mars so I don't see how it would be simpler/easier and or cheaper.
Quote from: rakaydos on 05/11/2021 04:06 pmQuote from: RanulfC on 05/11/2021 04:02 pmQuote from: electricdawn on 05/11/2021 03:01 pmI know of crew starship, tanker, cargo, lunar lander and maybe a deep space version (which is just a completely stripped down version, so very simple and very cheap).I see no reason why SpaceX would be unable to follow through with these.Starship (mixed crew/cargo or the 'standard' Starship), Tanker and Cargo. The "Lunar lander" makes zero sense for SpaceX to build as it would be a vastly inferior vehicle, and wasted effort when they could just 'sell' flights on a regular Starship. A 'deep space' version also doesn't make much sense given SpaceX's goals and ambitions. It significantly detracts from using the "basic 3" Starships for any and all missions and thereby supporting the economics of Starship.Elon: "You're right. Everything we wanted the falcon heavy to do, the Falcon 9 can do. Lets just cut our losses and cancel it."Gwynn: "You cant cancel it, we have contracts!"Just going to ignore the little fact that Falcon Heavy was not less capable than Falcon 9 then? And specifically that it COULD do more than the Falcon 9 which Lunar Starship can't? You are literally trying to use a totally different situation to illustrate a point that doesn't exist. A "better", or at least more applicable argument would be that SpaceX up and decided to abandon the Falcon 9/Dragon for an as of yet un-flown "Heavy Falcon" with a totally reusable Super-Dragon upper stage and then accepted development funding towards that LV with the stipulation that it would have an expendable upper stage that was based on the reusable design. You still have to design and develop the booster(s) and upper-stage as a prerequisite to deploying the system and meanwhile you can work on the customers 'requirement' that it be expendable and single use. There is literally NO conflict here.As for contracts, well see below...Quote from: electricdawn on 05/11/2021 04:14 pmUhm... Lunar Starship is required for the HLS contract? And I can also see a use as a pioneer Starship that lands on planets where there is no infrastructure and creates this infrastructure (ISRU, landing pad) for "regular" Starships to use.So, IMHO, this is a necessary step for Musk's dreams about Mars. At least IMHO."Development" of the suggested Lunar Starship is part of the HLS contract, let me repeat, you need a "Starship" to develop the "Lunar Starship" there is literally no conflict at this point as ANY development of Starship itself can be shown to be progress towards Lunar Starship. The only point where 'contractual' issues might be brought up is if by 2024 SpaceX has yet to fly a Starshp of any kind to orbit. (Possible) At which point questions may be asked but we've been here before and the 'answer' is going to be the same, keep slogging forward, especially if there is no 'alternative' available.Once SpaceX has a "Starship" on orbit they can demonstrate on-orbit propellant transfer and at that point it is pretty much a "Lunar Starship". Unless NASA wants to demand that it be expendable and of limited utility at which point SpaceX has the choice of agreeing to build a couple "one-off-really-bad-Starships" or making the argument that Starship itself fulfills the "Lunar Starship" requirements. (Which btw was their initial argument for proposing Starship for HLS)Randy
Isn't that what doomed Space Shuttle trying to accomplish too many roles?
That's exactly what my comparison is about. The base model is plenty from an engineering standpoint for anything the customers wanted to do... but SpaceX has a piece of paper that requires them to ALSO build specialized one-off hardware or forfit a bunch of money. SpaceX will build at least 2 specialized lunar starships because they told NASA they would. After those two are built, it's fair game for base starship.
Why are you swapping deep space with lunar lander? And I still do not see an issue with having a basic Starship and developing different versions from it that use the same basic frame.
So you're basically suggesting that the "Lunar Starship" will be indistinguishable from the "Passenger Starship," that any and all features needed for completing the HLS contract will be made into standard features that all passenger Starships include. That's plausible at least, but depends on whether a single solar panel design is appropriate for both "sitting on the lunar surface for a week" and "interplanetary journeys," whether adding interplanetary-only features (like increased life support, a hardened solar flare shelter, etc.) to HLS Starship is worth it, and whether they can get away with leaving the flaps on HLS Starship which will never be used. It may turn out that Starship has so much extra mass margin, they might as well just do everything. But I think if they could deliver an extra 10 tons to the lunar surface by making some minor modifications, they totally would do that.
That's exactly what my comparison is about. The base model is plenty from an engineering standpoint for anything the customers wanted to do... but SpaceX has a piece of paper that requires them to ALSO build specialized one-off hardware or forfeit a bunch of money. SpaceX will build at least 2 specialized lunar starships because they told NASA they would. After those two are built, it's fair game for base starship.
Quote from: rakaydos on 05/11/2021 05:28 pmThat's exactly what my comparison is about. The base model is plenty from an engineering standpoint for anything the customers wanted to do... but SpaceX has a piece of paper that requires them to ALSO build specialized one-off hardware or forfit a bunch of money. SpaceX will build at least 2 specialized lunar starships because they told NASA they would. After those two are built, it's fair game for base starship.RanulfC's argument is that they don't need to build a specialized, one-off piece of hardware for the HLS contract, they just need to build some piece of hardware which meets the requirements of the contract. So they could build a generic "Passenger Starship" which happens to do everything necessary for the HLS mission...in addition to also being appropriate for carrying colonists to Mars, for example. Whether it's cheaper to design separate "Lunar" and "Mars colonization" Starships, or design a single "Passenger" Starship that has all the features of both and which you'll use for all passenger missions, is a separate question. Designing two versions is inherently more expensive than one, but if you end up building an unnecessarily-complex vehicle with features you don't need but still are paying to include, that's also more expensive.
Quote from: Khadgars on 05/11/2021 02:58 pmIsn't that what doomed Space Shuttle trying to accomplish too many roles?STS tried to do too much in one (very expensive) design. SS is developing variants on one (relatively cheap) design to address different uses/markets.
Like every LV, SS will have problems. But it’s not repeating that particular STS mistake.