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https://www.youtube.com/watch?v=_t6pLNEXh18
Space X are one of the three bidders to receive funding from NASA for developing a human-rated lunar lander. Space X are picking up well over $100 million to develop Starship as a lunar lander. This of course will help the overall Starship development programme and grow Space X's expertise in off Earth landings.
Last edited by louis (2020-05-01 16:08:54)
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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Louis,
They still need to develop an outrigger landing gear system for this thing. If they do that, then the only more stable option I see is the one from Dynetics. The SpaceX option is fully reusable, but the Dynetics option only dumps a couple of empty propellant tanks. I also see that now SpaceX (Dragon XL) and Orbital ATK are developing craft of the kind I spoke of years ago for delivery of small cargos to the lunar gateway.
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"outrigger landing gear system" - you mean like stabilisers on a child's bike?
Louis,
They still need to develop an outrigger landing gear system for this thing. If they do that, then the only more stable option I see is the one from Dynetics. The SpaceX option is fully reusable, but the Dynetics option only dumps a couple of empty propellant tanks. I also see that now SpaceX (Dragon XL) and Orbital ATK are developing craft of the kind I spoke of years ago for delivery of small cargos to the lunar gateway.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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I see they have a solution to not digging a crater on the Moon when they land. That seems good.
I am very surprised. And he spoke about refueling it in lunar orbit. I a bit confused about that.
I have watched some other info, and have the impression that the Starship-Lunar lander will only travel from lunar orbit to land and back again repeatedly. That's why the lunar orbit refueling if that is true.
And yes they could put huge landing gear on that.
https://www.bing.com/videos/search?q=Sp … ORM=VDQVAP
https://www.youtube.com/watch?v=INdytSaXzZc
I would think that if it was for freight only, you could just use it until you loose it. Then send in a replacement.
Last edited by Void (2020-05-01 16:44:18)
Done.
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Louis,
You can think of it as "training wheels" or you can think of it as a very stable landing gear system that's tolerant of landing on slopes and on soft or hard surfaces, etc. As someone interested in aircraft design, stability is a very important and ever-present concept. Landing on a steel-reinforced concrete pad is nothing like landing on sand. It just is. You can fight physics every step of the way, or you can accept that stability is an actual problem, adequately address it, and then move on from there.
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Or you can send a smaller craft to build a landing pad.
We don’t design 787’s to land on rough terrain.
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Just because we don't design 787's to land on dirt does NOT mean that we cannot design them to do it. Actually, we can. The C-5 Galaxy transport was specifically designed to support dirt strip operations. It could and did land and take off from dirt strips. They avoided doing so for the most part, because the extra dust exposure shortened engine life. Same was true of the C-17.
The difference here ain't the dirt strip, and it ain't the size, it's the tall tail-sitter configuration. All rocket landers so far have been tail sitters. All but one so far have been deliberately designed for extra static stability by having the landing leg span exceed height to vehicle center of gravity (now you know why the DC-X was conical). The exception here is Spacex, and they will pay a price for ignoring the static stability effect, in conjunction with surface bearing stresses and properties.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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Only because I read it, not because I am rocket wise, I understand this about a Starship landing on the Moon.
It is going to be very hard to throttle, the engines down properly to land in the low gravity field. I also believe that it is true that the Vacuum Raptors are not gimbaled (I think that is the word).
So, in my opinion, even if you were landing on a hard landing pad, I think you would want those clusters of side canted thrusters, to stabilize a vertical position, especially if you are relying on those stubby little legs they have shown so far.
I think however it would be silly not to put substantial legs on the vehicle in LEO.
Done.
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Mark,
In order to do much exploration of remote sites, the landing pad would have to be mobile. Again, I fail to understand why SpaceX wouldn't design landing gear that permits landing in rough terrain, because that's exactly what any other aerospace engineering company would do for an aircraft designed to land in rough terrain. The most obvious solution is continually ignored in favor of increasingly complex alternatives to an otherwise readily solvable problem with proper landing gear design.
The 787's design team didn't demand that their mammoth bird land on little nubbins for tires to save a little weight. Instead, they kept the CG low to the landing surface using a horizontal landing configuration and used wide track bogies with massive tires to assure that the fully loaded airframe exerts a ground pressure that remains well within the bearing strength of the airport runways it was intended to land on.
If the US Army wants C-130's to land at a remote site, then the US Air Force sends a team ahead of their C-130's with a test kit to test the soil bearing strength in the area they want to land in. If the soil won't bear the weight of the bird, then they select an alternate landing site or they don't land there.
After all the work required to get it there, do we really need to lose a Starship on the moon to re-discover basic physics, or can we accept that Starship's current landing gear design isn't going to work for rough-field operations (at present, 100% of the lunar and Martian surface)?
I know we have lots of SpaceX fans here, and I'm a fan of their work as well, but someone needs to politely inform their engineering team that rough field landings are not compatible with the same landing gear designs that work on steel flight decks or steel-reinforced concrete landing pads. I honestly can't believe that that point is controversial in any way.
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I'd like to say Space X know what they're doing but since the welding fiasco, I'm not so sure! However, I do think artists' CGI renderings are often meant to obfuscate (so that competitors remain in the dark) more than they are meant to enlighten about true intent.
That said, it seems to me that the other two winners are stuck in the Apollo era and Space X have a new approach that meets the requirements of what we want to achieve (the quick creation of a permanent base). I don't think the rough field challenge is nearly as big a problem as people are suggesting and it's something that can be tested in all sorts of conditions on Earth. Obviously wherever they choose to land on the Moon is not going to be covered in feet-deep dust. They are going to look for a relatively dust-free area - hard on the lunar surface I know, but there is substantial variation.
Mark,
In order to do much exploration of remote sites, the landing pad would have to be mobile. Again, I fail to understand why SpaceX wouldn't design landing gear that permits landing in rough terrain, because that's exactly what any other aerospace engineering company would do for an aircraft designed to land in rough terrain. The most obvious solution is continually ignored in favor of increasingly complex alternatives to an otherwise readily solvable problem with proper landing gear design.
The 787's design team didn't demand that their mammoth bird land on little nubbins for tires to save a little weight. Instead, they kept the CG low to the landing surface using a horizontal landing configuration and used wide track bogies with massive tires to assure that the fully loaded airframe exerts a ground pressure that remains well within the bearing strength of the airport runways it was intended to land on.
If the US Army wants C-130's to land at a remote site, then the US Air Force sends a team ahead of their C-130's with a test kit to test the soil bearing strength in the area they want to land in. If the soil won't bear the weight of the bird, then they select an alternate landing site or they don't land there.
After all the work required to get it there, do we really need to lose a Starship on the moon to re-discover basic physics, or can we accept that Starship's current landing gear design isn't going to work for rough-field operations (at present, 100% of the lunar and Martian surface)?
I know we have lots of SpaceX fans here, and I'm a fan of their work as well, but someone needs to politely inform their engineering team that rough field landings are not compatible with the same landing gear designs that work on steel flight decks or steel-reinforced concrete landing pads. I honestly can't believe that that point is controversial in any way.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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Louis,
I have no clue what artistic CGI renderings are meant to do or not do, but Elon Musk has publicly stated that their CGI animations were intended to reflect what they were actually attempting to do and what the spacecraft was actually supposed to look like, from an engineering standpoint. None of their competitors are trying to build giant fully reusable stainless steel rockets, so I fail to understand how their competitors would suddenly become "enlightened" about something that none of them are trying to do in a way similar to what SpaceX is trying to do. ULA hasn't changed plans from Vulcan development in light of Starship Super Heavy, nor has Blue Origin changed their New Glenn plans in response to SpaceX's new rocket.
Maybe the "mind's eye" has a way of seeing what it wants to see, but I don't see what you're describing at all. What I see looks like a total rush job, replete with shoddy workmanship and the resultant predictable yet unnecessary failure of things like pressure tests, wherein rocket components are needlessly destroyed before ever being assembled into a functional rocket of any kind. I want to see something basic and fundamental to rocketry with liquid propellants, like pressure tests, executed successfully before changing my opinion on this.
You're correct. Rough field landings CAN be tested here on Earth. For some inexplicable reason, that hasn't been done yet using existing booster core hardware from the Falcon program. Surely such tests, if "propellant is cheap", as Elon Musk claims, could've been tested several times already given the amount of money "up in smoke" from comparatively much simpler (yet still failed) pressure tests. So that really begs the question, "Why wasn't that tested?" They already have "flight proven" booster cores stacking up at the factory that they don't intend to re-fly on orbital missions, so why didn't one of their engineers feel the need to do that kind of testing using booster cores with known-working computer control systems and the ability to successfully hold pressure? I have a feeling that it's not as simple and easy as you're suggesting it is.
Regarding what SpaceX's competitors are doing with their lunar landers, they've clearly chosen much more conservative designs that are intended to fulfill a specific role. That's typically how aerospace engineering is actually done whenever something must be delivered on time and within budget. You don't start "experimenting" unless it's absolutely necessary to achieve a specific design requirement. The lunar lander needs to be really good at landing on unimproved surfaces with variable bearing strength, thus the other two designs that received funding have wide track landing gear, low CG's, and reuse pieces of existing flight-qualified hardware in a novel new configuration. The moon is supposed to be a proving ground for future Mars missions. That means extended duration life support, radiation protection, dust abrasion damage mitigation, and ISRU capabilities all need to be thoroughly tested and refined to enable Mars missions that stand a good chance of success in the absolutely unforgiving environments of deep space and the moon or Mars. For lunar missions, there's an abort option. No such option exists for Mars missions, thus nothing will be going to Mars until basic operational test validation has been completed. NASA has faith that SpaceX's world-class landing capabilities merit further development and I agree with NASA's decision, but that doesn't mean they get a "pass" on basic engineering requirements for rough field landings.
I also see that you're still laboring under this belief that SpaceX gets to pick and choose precisely where to land their rocket. If there was a GPS system around the moon and we knew exactly what the bearing strength of the regolith was from actual testing, then maybe that would work acceptably well. We don't have or know either of those things, so guessing at it is a good way to get people killed and bring the program to a screeching halt. After you kill someone by "guessing at it", the US Federal Aviation Administration WILL ground your aircraft or spacecraft while they investigate. They hold authority over Boeing, SpaceX, ULA, and even NASA.
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Louis,
I have no clue what artistic CGI renderings are meant to do or not do, but Elon Musk has publicly stated that their CGI animations were intended to reflect what they were actually attempting to do and what the spacecraft was actually supposed to look like, from an engineering standpoint. None of their competitors are trying to build giant fully reusable stainless steel rockets, so I fail to understand how their competitors would suddenly become "enlightened" about something that none of them are trying to do in a way similar to what SpaceX is trying to do. ULA hasn't changed plans from Vulcan development in light of Starship Super Heavy, nor has Blue Origin changed their New Glenn plans in response to SpaceX's new rocket.
Maybe the "mind's eye" has a way of seeing what it wants to see, but I don't see what you're describing at all. What I see looks like a total rush job, replete with shoddy workmanship and the resultant predictable yet unnecessary failure of things like pressure tests, wherein rocket components are needlessly destroyed before ever being assembled into a functional rocket of any kind. I want to see something basic and fundamental to rocketry with liquid propellants, like pressure tests, executed successfully before changing my opinion on this.
I think there's evidence that Musk, like all big players does tell half the story half the time, in order to confuse the opposition, which could be the Chinese as much as Boeing or Blue Origin.
You're correct. Rough field landings CAN be tested here on Earth. For some inexplicable reason, that hasn't been done yet using existing booster core hardware from the Falcon program. Surely such tests, if "propellant is cheap", as Elon Musk claims, could've been tested several times already given the amount of money "up in smoke" from comparatively much simpler (yet still failed) pressure tests. So that really begs the question, "Why wasn't that tested?" They already have "flight proven" booster cores stacking up at the factory that they don't intend to re-fly on orbital missions, so why didn't one of their engineers feel the need to do that kind of testing using booster cores with known-working computer control systems and the ability to successfully hold pressure? I have a feeling that it's not as simple and easy as you're suggesting it is.
I wouldn't myself see a lot of point in testing a non-Mars or non-lunar rocket on Earth. The time will come when roughfield landing tests are required.
Regarding what SpaceX's competitors are doing with their lunar landers, they've clearly chosen much more conservative designs that are intended to fulfill a specific role. That's typically how aerospace engineering is actually done whenever something must be delivered on time and within budget. You don't start "experimenting" unless it's absolutely necessary to achieve a specific design requirement. The lunar lander needs to be really good at landing on unimproved surfaces with variable bearing strength, thus the other two designs that received funding have wide track landing gear, low CG's, and reuse pieces of existing flight-qualified hardware in a novel new configuration. The moon is supposed to be a proving ground for future Mars missions. That means extended duration life support, radiation protection, dust abrasion damage mitigation, and ISRU capabilities all need to be thoroughly tested and refined to enable Mars missions that stand a good chance of success in the absolutely unforgiving environments of deep space and the moon or Mars. For lunar missions, there's an abort option. No such option exists for Mars missions, thus nothing will be going to Mars until basic operational test validation has been completed. NASA has faith that SpaceX's world-class landing capabilities merit further development and I agree with NASA's decision, but that doesn't mean they get a "pass" on basic engineering requirements for rough field landings.
No one's giving Space X a free pass. One point though - Space X might well land their own crew on the Moon as a demonstration for NASA! They do intend to incorporate pre-missions to the lunar surface.
I don't think lunar landings are required to prove Mars landings...I think they might end up being something of a diversion, since lunar surface conditions are so different. However, if there's money on offer from NASA, you might as well go for it, and take your lessons as they come. I think in terms of gathering info for a Mars landing, landing on Earth in selected locations e.g. rocky deserts would be helpful.
I also see that you're still laboring under this belief that SpaceX gets to pick and choose precisely where to land their rocket. If there was a GPS system around the moon and we knew exactly what the bearing strength of the regolith was from actual testing, then maybe that would work acceptably well. We don't have or know either of those things, so guessing at it is a good way to get people killed and bring the program to a screeching halt. After you kill someone by "guessing at it", the US Federal Aviation Administration WILL ground your aircraft or spacecraft while they investigate. They hold authority over Boeing, SpaceX, ULA, and even NASA.
I think it would depend on where the death occurred. If it happened on the lunar surface I think it might be a different attitude from the FAA.
One thing I would say is that NASA, ULA and Boeing can't really escape the USA. I think Space X could if push came to shove. In terms of "realpolitik" that is a powerful bargaining counter they have, especially as they become a bigger and bigger player. There's nothing to stop Space X relocating to South Korea, Taiwan, Singapore, UK or other countries.
Not to rehearse all the arguments, I take a much more optimistic view of what we know about surface conditions on the Moon although, I would say I would be less relaxed about landing a Starship on the Moon than Mars. I think the Moon is a lot more treacherous. Areas of smooth lava flow seem to be the favoured landing sites:
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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Louis,
Argue the point all you wish, but no rough field landing demonstration equals no flights to a rough field. 100% of the moon and Mars are rough fields. There are no landing pads on the moon or Mars. If SpaceX's rocket can't land with acceptable stability in rough field conditions, then it will tip over and explode. The mission is over at that point.
Oh, and by the way...
Whenever you take money from the US DoD or NASA to develop your rocket, your rocket technology is subject to ITAR ever after. The technology your company develops using government money only continues to be the property of your company for so long as you adhere to the rules regarding what you're permitted to do with it. SpaceX doesn't have any "bargaining chips" with the US government, in that regard. In any event, you follow the rules or your corporate assets are seized and you'll be arrested. "I'm special" isn't likely to be an accepted form of defense in court, either.
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The landing system on Deep Space Starship will be developed the same way the original designs are: build it, test it, wreck it. Having long extensible landing leg similar to those of Falcon 9 would seem to be a realistic answer. Once extended, they would never retract in the vacuum of space.
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There was some speculation on the latest Felix program last night about extensible legs vis a vis Falcon 9; Starship needs a lot more load bearing area and wider footprint for rough and inhospitable terrain.
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Presumably you could have additional legs for stability, rather than direct load bearing...the equivalent of a walking stick for humans.
There was some speculation on the latest Felix program last night about extensible legs vis a vis Falcon 9; Starship needs a lot more load bearing area and wider footprint for rough and inhospitable terrain.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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So is Space x current version of starship to scale for a lunar lander and if so what are we looking at for capability in words....
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