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Two Starships in "bolas" rotation
The SpaceX plans for the first Mars trips involve two Starships making
the trip at the same time. The SpaceX videos show a Starship flying alone, in a fixed attitude (pointing away from the Sun) thus in free fall. From other sources there is some concern that a multi-month weightless trip may incapacitate the pilots and passengers, for example resulting in blurred vision when they are again subjected to acceleration or gravity. Here I propose a possible solution: cable the two Starships together in a nose-to-nose attitude and rotate them to provide simulated gravity during the trip. Such rotating spaceship combinations have been suggested before, of course, but it seems to me that the Starship design is uniquely apt for this. The two Starships would be connected by two cables (wire ropes) starting from the outer ends of the two articulated aft fins and passing through non-load-bearing connections ("rings", "eyelets") at the outer ends of the two front fins. The weight (centripetal acceleration) of each Starship would thus be carried by the outer ends of the aft fins, just as when the Starship has landed and these fins act as two of the three landing legs. The connection to the front fins would stabilize the Starship in a "nose-up" position. Alternatively, a third cable could connect to the third (dorsal) landing leg for an even closer emulation of the landed, upright state. The articulation (rotation) range of the fins seems (from the videos) large enough to place the pull from the cables close to the center of gravity of the Starship -- even if the third landing leg is not used -- so the simulated gravity would be aligned with the long axis of the Starship, as in the landed position. For a Mars trip, a simulated Martian gravity level could be used, giving less stress and weaker Coriolis effects than full Earth gravity. The same two-Starship bolas system could be used in Earth orbit to test the long-term effects of Martian gravity levels before Mars trips are undertaken. There may be a thermal problem. The Starship carries cryopropellants which must not evaporate away during the trip from Earth to Mars or vice versa. In the SpaceX trip videos, the Starship points away from the Sun, and is furthermore shadowed by a semi-circular fan of solar cells unfolded at the aft end of the Starship. This prevents solar heating of the Starship structure, which may be important to limit propellant evaporation. In a rotating Starship pair the same shadowing is not possible. The illumination conditions depend on the orientation of the rotation axis. For human comfort, it seems best for the rotation axis to point at the Sun, which means that the direction of incoming sunlight and the position of the Sun as seen from the Starships are constant and not rotating. (Another nice feature of this orientation is that the Starships could be slowly rolled around their long axes to simulate a day-night cycle.) However, this also means that both Starships are constantly illuminated and heated from one side, which may cause propellant evaporation. If the rotation axis is perpendicular to the Sun direction, the average solar illumination of the Starships is reduced, but is still larger than in the fixed away-from-Sun attitude. As seen from a Starship the Sun rotates around the Starship, front to aft and back again, once per Starship rotation. This rapid rotation of the illumination may be very distracting to the passengers. A lesser problem may be how to mount the solar cell fans. Their original aft-facing position at the aft Starship end is now bad, because the fans would not be well illuminated and would be stressed by centripetal forces. One solution is to mount the solar cell fans on the cables, at the center of rotation. If the rotation axis does not point at the Sun, or if the centripetal forces are still too strong even this close to the axis, the fans could be decoupled from the rotation by a rotating electrical coupling at the rotation axis. So that's the suggestion. Comments are welcome... -- Niklas Holsti Tidorum Ltd niklas holsti tidorum fi . @ . |
#2
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Two Starships in "bolas" rotation
On 5/21/2019 2:15 PM, Niklas Holsti wrote:
So that's the suggestion. Comments are welcome... This very type of configuration of Starships has been discussed here before. It is not an unrealistic approach. However I was unaware that the SpaceX plan called for two Starships to make the journey all the way to Mars. Two Superheavys (or whatever SpaceX is calling the BFR these days) where planned but one of them was not a Starship destined for Mars but a fueling pod for the Starship that was. That's the plan I remember. But frankly I think Mars is a long way off. In fact the Moon is becoming a major distraction. And that actually makes sense since all this hardware can be tested out far more easily on lunar missions. There is a push within NASA to refocus on the Moon and a lunar base, by any means possible. If that means contracting with private enterprise to do it, so be it. We will have to wait and see how Starship does in this regard. We are along a familiar trajectory here. Same one as was taken for recoverable Falcon 9 stages. I think Starship will focus on P2P suborbital trajectories first to establish launch and return procedures that must work anyway. Then a push to orbit, then a push beyond. Opening out the envelope becomes easier the further along the curve you get. However the first part of that curve is the hardest. Or would appear so from where we stand today. What is interesting, to me, is how much SpaceX is going to rely on automation before committing crew to the Starship. At what point will they crew the vehicle? After it completely passes all P2P and orbital tests or before? Will crew be considered an essential part of Starship operation or not? (i.e. will Starship require pilots or provide crew with a flat screen they can follow the action on?) If the past is any indication I'd say no. At least not in the initial stages. Your bolas configuration could be tried out in LEO. If such a plan were part of a SpaceX requirement this would make a lot of sense. It could provide an orbital gravity lab "on the cheap" in the sense that it doesn't require "bending steel" that a specialized orbital lab would. But you bolas configuration points to a far far deeper question than the mere mechanics of generating artificial g in space. The data points we'd get from the physiological effects of long term operations on the lunar surface might also make the need for a gravity lab moot. If humans can do "fine" in lunar gravity, there would be no rational supposition that Mars would be worse. At least until we get to Mars. I put the word fine in quotes because there are going to be physiological effects. The key question is whether we define those effects as debilitating. Some might consider the inability to return to Earth as disabling. Others might not. Same with Mars. The key in all cases is whether medically humans can adapt to a sudden change in 'g' long term. Is life in space like smoking? If you are guaranteed to die after 15 years in lunar surface conditions, will that be a deterrent? Or would the experience of a (short) life in space on the moon be worth every otherwise lost year? Let's hope we're not forced into that kind of choice, but right now there is no reason to say it can't happen. We need more data. Dave |
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Two Starships in "bolas" rotation
In article , says...
On 5/21/2019 2:15 PM, Niklas Holsti wrote: So that's the suggestion. Comments are welcome... This very type of configuration of Starships has been discussed here before. It is not an unrealistic approach. However I was unaware that the SpaceX plan called for two Starships to make the journey all the way to Mars. Two Superheavys (or whatever SpaceX is calling the BFR these days) where planned but one of them was not a Starship destined for Mars but a fueling pod for the Starship that was. That's the plan I remember. This is all still very notional since Starship/Super Heavy has yet to fly. But I do believe the plan was always for Starships to make the journey to Mars in pairs. That would provide redundancy. Tankers are a separate thing which are obviously needed in order to top off the propellant tanks of Starship. And to do this "right", IMHO, you need even more Starships. What you'd want to do is to preposition a return Starship (or at least a propellant production Starship which would stay on Mars) which would produce propellant for the return trip. Once that's "full", you'd send your crewed ship. Otherwise, there's no coming back if the crewed Starship fails to make its own propellant once on Mars. The only way the delta-V case for crewed Mars missions is by using in situ propellant production. But frankly I think Mars is a long way off. In fact the Moon is becoming a major distraction. Agreed. And that actually makes sense since all this hardware can be tested out far more easily on lunar missions. Disagree. The hardware will be very different between the two. For starters, the landing mode is different. Mars has a thin atmosphere which you want to use to shed as much delta-V as possible. The moon lacks any atmosphere. This also means that in situ propellant production will be completely different. On Mars it will rely on CO2 from the atmosphere. On the moon, it would rely on any water which can be produced from local resources. This means different fuels will be produced (methane on Mars, LH2 on the moon). So even the engines will need to be different. In fact, the difference in atmospheres drives a lot of the engineering, so the hardware just won't be the same at all. Second, power generation challenges are different. The long lunar night makes for a large electricity storage requirement. Mars night is much shorter. Mars dust storms provide a challenge for solar arrays. The moon has no dust storms, but does have dust which can be kicked up by human and robotic activity and then stick to surfaces via static electric forces. Third, spacesuits are likely to be quite different. The 1/6 gravity of the moon allows for much more massive designs than Mars suits. This is a huge challenge when designing practical Mars suits. Fourth, dust challenges are different. Both bodies have dust. But the dust is hugely different. On Mars you have dust storms and the dust can have perclorates in it which make it toxic, so it has to be dealt with in order to prevent humans from coming into contact with it. On the moon, the dust has super sharp edges due to no weathering and it is famously abrasive. It's primary health hazard would be the lungs, which don't tolerate small particles of any origins. But lunar dust is largely non-toxic in other respects. So even though "dust bad", the solutions for dealing with that dust might end up being different due to the different properties of that dust. I'm sure I could go on, but I think I've made my point. If you want to go to Mars, go to Mars. Going to the moon first is largely a distraction because most of that "experience" gained will be thrown out and nearly everything will need to be re-engineered specifically for the Martian surface environment. There is a push within NASA to refocus on the Moon and a lunar base, by any means possible. If that means contracting with private enterprise to do it, so be it. We will have to wait and see how Starship does in this regard. Clearly, especially since the current NASA plan of record doesn't include Starship in any meaningful way. It still relies heavily on SLS/Orion, so we will be limited to one crewed mission per year. That's pretty weak sauce considering how "close" the moon is. We are along a familiar trajectory here. Same one as was taken for recoverable Falcon 9 stages. I think Starship will focus on P2P suborbital trajectories first to establish launch and return procedures that must work anyway. Only if they can find a paying customer. Such flights without Super Booster would be severely limited in P2P range. All P2P promotional videos made to date show Starship being lofted by Super Booster. I personally think we'll see Starship only flights for testing, but nothing else. Then a push to orbit, then a push beyond. I personally think the "push beyond" will take a very long time. Once Starship/Super Booster is flying to earth orbit, its primary mission will be Starlink satellite deployment. Yes you can keep flying up to 60 Starlink satellites at a time on Falcon 9 (more polar orbits will either have less satellites or require Falcon Heavy launches), but when the goal is on the order of 12,000 satellites (by the mid 2020s), that's at least 200 Falcon/Falcon Heavy launches in a few short years! If we guess those launches cost on average $50 million each, that's $10 billion in launch costs just to get the initial constellation up and running! And keep in mind the lifetime of these satellites is relatively short (from memory something like 3-5 years), so this isn't a "one time" thing. If Starlink is successful, SpaceX will be continuously launching its own Starlink satellites for some time to come. SpaceX needs Starlink for the potential revenue to attract investors to develop Starship/Super Heavy. But SpaceX also needs Starship/Super Heavy to launch and maintain the Starlink constellation. Mars is still Musk's ultimate goal, but Starlink will need to come first in order to provide the massive cash flow needed to turn Starship from a cargo launcher into a true crewed spaceship capable of performing an actual Mars mission. IMHO, of course. Opening out the envelope becomes easier the further along the curve you get. However the first part of that curve is the hardest. Each part of the development of Starship will present its own challenges. But getting it from development to a cargo launcher involves the same types of challenges that Falcon development had. They've done this before. Going from cargo launcher to crewed Mars spacecraft involves a whole host of other challenges that SpaceX has yet to face. That's where the true "unknown unknowns" are hiding. Talking more about the configuration of the two Starships on an actual flight to Mars is a tad premature, IMHO, so I'm going to snip the rest of the discussion, interesting as it is. Jeff -- All opinions posted by me on Usenet News are mine, and mine alone. These posts do not reflect the opinions of my family, friends, employer, or any organization that I am a member of. |
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Two Starships in "bolas" rotation
David Spain wrote on Sat, 25 May 2019 08:58:45
-0400: On 5/21/2019 2:15 PM, Niklas Holsti wrote: So that's the suggestion. Comments are welcome... This very type of configuration of Starships has been discussed here before. It is not an unrealistic approach. However I was unaware that the SpaceX plan called for two Starships to make the journey all the way to Mars. The SpaceX plan (which I consider wildly optimistic) is to send two cargo Starships to Mars in 2022, followed by two more cargo Starships plus two crewed Starships in 2024. Moon flights before 2022. I think you need to shift everything 2-4 years to the right to get to something that removes the "wildly" from "wildly optimistic". Two Superheavys (or whatever SpaceX is calling the BFR these days) where planned but one of them was not a Starship destined for Mars but a fueling pod for the Starship that was. That's the plan I remember. It takes at least 3-4 tanker launches to refuel a single Starship for a Mars (or a Moon, if you intend to land and return to Earth) trip. But frankly I think Mars is a long way off. In fact the Moon is becoming a major distraction. And that actually makes sense since all this hardware can be tested out far more easily on lunar missions. There is a push within NASA to refocus on the Moon and a lunar base, by any means possible. If that means contracting with private enterprise to do it, so be it. We will have to wait and see how Starship does in this regard. I'm not convinced NASA has its own direction, other than to build some hardware (like Gateway). They vacillate with whatever the then current President wants. So we've seen things go from Mars to Asteroid Retrieval to Moon over the last three Presidents. Musk plans on Mars, regardless of what NASA does. Blue Origin appears to be Moon focused. We are along a familiar trajectory here. Same one as was taken for recoverable Falcon 9 stages. I think Starship will focus on P2P suborbital trajectories first to establish launch and return procedures that must work anyway. I think pursuit of P2P as a first goal is unlikely. Expect to see some non-orbital hopper tests, followed by some hopper 'dives' to validate thermal protection and such. These will all launch and return in Texas with no Falcon Super Heavy booster involved. From there the next stop is probably the free return trip around the Moon. Then a push to orbit, then a push beyond. Opening out the envelope becomes easier the further along the curve you get. However the first part of that curve is the hardest. Or would appear so from where we stand today. What is interesting, to me, is how much SpaceX is going to rely on automation before committing crew to the Starship. At what point will they crew the vehicle? After it completely passes all P2P and orbital tests or before? Will crew be considered an essential part of Starship operation or not? (i.e. will Starship require pilots or provide crew with a flat screen they can follow the action on?) If the past is any indication I'd say no. At least not in the initial stages. I don't think 'crew' will ever be considered 'essential' just to fly the vehicle. After all, the Mars plan has the first two ships to Mars as cargo only. And that's really what you want, since you want your first trips to do things like set up something to manufacture fuel so that your later manned flights can refuel to get home. Your bolas configuration could be tried out in LEO. If such a plan were part of a SpaceX requirement this would make a lot of sense. It could provide an orbital gravity lab "on the cheap" in the sense that it doesn't require "bending steel" that a specialized orbital lab would. Except such a plan is NOT part of the SpaceX requirements. THEIR plan is to do transits that are sufficiently fast in a ship that is large enough to carry along whatever exercise equipment is required. -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
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Two Starships in "bolas" rotation
On 19-05-25 15:58 , David Spain wrote:
On 5/21/2019 2:15 PM, Niklas Holsti wrote: So that's the suggestion. Comments are welcome... This very type of configuration of Starships has been discussed here before. Ah, I must have missed that somehow (which surprises me as I tend to read all posts). Apologies for being redundant. A belated web search brings up a couple of YouTube videos of such proposals. However, in these videos the Starships are connected by a nose-to-nose cable, which means that the Starship structures are stressed unnaturally in tension, and not in compression as in my suggestion where the cables are connected to the aft fins. It is the fins that IMO make the Starship so intrinsically suitable for a bolas pair. It is not an unrealistic approach. However I was unaware that the SpaceX plan called for two Starships to make the journey all the way to Mars. One Starship could make the trip alone, but in the 2017 "Making Life Multiplanetary" presentation (https://youtu.be/tdUX3ypDVwI), starting at 36:52 Musk describes the SpaceX "aspirational" plan as follows: in 2022: cargo-only missions to Mars with "at least 2" ships in 2024: two cargo ships and two crew ships. Later trips involve even larger numbers of ships at the same time. Musk does not say that the ships travel at exactly the same time. Constraints on the number of Tankers or the Super Heavy launch rate may mean that some time (a week or two?) passes between full retanking of the first Starship and the full retanking of the second Starship. But waiting a week or two in Earth orbit would not be a large increase in the overall trip time of the first Starship. Two Superheavys (or whatever SpaceX is calling the BFR these days) where planned but one of them was not a Starship destined for Mars but a fueling pod for the Starship that was. That's the plan I remember. Super Heavy is the BFR first stage (booster). Starship and Tanker are two versions of the second-stage-and-ship (BFS). At 27:29 in the video Musk explains the tanking of a Starship in Earth orbit. He ends up with five Tankers (five Super Heavy + Tanker launches) to fully refill one Starship. At 33:51 Musk shows four Tankers for a Mars trip. So five or six Super Heavy launches for one Starship to Mars. But frankly I think Mars is a long way off. In fact the Moon is becoming a major distraction. And that actually makes sense since all this hardware can be tested out far more easily on lunar missions. Yes indeed, so why would it be a distraction? If you mean the Yusaku Maezawa trip around the Moon, it does not require the Super Heavy + Starship + Tanker system to do anything that a Mars trip would not require. The only major difference that comes to mind is that a shorter-duration life-support system could be used on the round-the-Moon trip, with less recycling than during the longer Mars trip. But that does not seem to be a major distraction. There is a push within NASA to refocus on the Moon and a lunar base, by any means possible. If that means contracting with private enterprise to do it, so be it. We will have to wait and see how Starship does in this regard. I hope that SpaceX does not try design a different system for NASA's Moon plans. Building a SpaceX version of, say, the Blue Origin Moon lander _would_ be a distraction. Unfortunately, as I understand NASA's current Moon plans, Starship does not fit -- it has no need for the LOP-G, nor does it fall apart into the multiple "elements" (transfer, lander, returner) of the NASA relay-race. I think Starship will focus on P2P suborbital trajectories first to establish launch and return procedures that must work anyway. Then a push to orbit, then a push beyond. Opening out the envelope becomes easier the further along the curve you get. Yes, as Musk has explained and as the "Starhopper" is close to start doing (although very sub-orbital :-). What is interesting, to me, is how much SpaceX is going to rely on automation before committing crew to the Starship. At what point will they crew the vehicle? After it completely passes all P2P and orbital tests or before? Will crew be considered an essential part of Starship operation or not? (i.e. will Starship require pilots or provide crew with a flat screen they can follow the action on?) If the past is any indication I'd say no. At least not in the initial stages. AIUI the Tanker will be uncrewed, as will the cargo missions to Mars, so I don't see why the Starship should require a crew. Your bolas configuration could be tried out in LEO. Indeed (and as I said). If such a plan were part of a SpaceX requirement this would make a lot of sense. "Requirement"? From whom? SpaceX will surely test the Starship's endurance in space conditions and it must be easier to do that in Earth orbit than in deep space. But perhaps some deeper orbits will be tried, too, for radiation soaks. It could provide an orbital gravity lab "on the cheap" in the sense that it doesn't require "bending steel" that a specialized orbital lab would. That's the nice thing about the Starship. It is big enough to be a "home on wheels", for traveling and living in. But you bolas configuration points to a far far deeper question than the mere mechanics of generating artificial g in space. The data points we'd get from the physiological effects of long term operations on the lunar surface might also make the need for a gravity lab moot. If humans can do "fine" in lunar gravity, there would be no rational supposition that Mars would be worse. "If", yes. However the trip from Earth to Mars would still be several months of zero-gee, which currently is seen as debilitating upon sudden transition to one gee. But perhaps it will turn out to be OK for a sudden transition to Martian 1/3 gee. -- Niklas Holsti Tidorum Ltd niklas holsti tidorum fi . @ . |
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Two Starships in "bolas" rotation
On 19-05-26 15:16 , Jeff Findley wrote:
... Once Starship/Super Booster is flying to earth orbit, its primary mission will be Starlink satellite deployment. Yes you can keep flying up to 60 Starlink satellites at a time on Falcon 9 (more polar orbits will either have less satellites or require Falcon Heavy launches), but when the goal is on the order of 12,000 satellites (by the mid 2020s), that's at least 200 Falcon/Falcon Heavy launches in a few short years! If we guess those launches cost on average $50 million each, that's $10 billion in launch costs just to get the initial constellation up and running! According to Wikipedia, $10 billion is indeed the Starlink cost estimate. Starlink launches would use the "satellite delivery" version of Starship, right? So that has to be developed. But it seems to me that if these things are reusable, and rapidly reusable, to the degree that SpaceX is planning, one or two Super Heavy boosters and one or two satellite deliverers should be enough to finish building Starlink and maintaining it. That is an operational use of Super Heavy and the Starship. If Starlink proves to work after the minimal number of satellites is up, it seems likely that SpaceX will be able to finance and run such Starlink operations in parallel with further development of the crewed Starship version and the Tanker version. And keep in mind the lifetime of these satellites is relatively short (from memory something like 3-5 years), so this isn't a "one time" thing. I think that lifetime refers to a failed, dead satellite, in the lower orbits, yes? AIUI working satellites use ion engines that will extend their lifetime. (There are developments in air-breathing ion enginges for very low Earth orbits that could make the lifetime independent of the launched propellant mass.) If Starlink is successful, SpaceX will be continuously launching its own Starlink satellites for some time to come. Yes, but if those launches are part of day-to-day Starlink operations, reusing the same launchers, why should they prevent further development aiming at Mars? -- Niklas Holsti Tidorum Ltd niklas holsti tidorum fi . @ . |
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Two Starships in "bolas" rotation
Niklas Holsti wrote on Sun, 26 May
2019 19:32:54 +0300: On 19-05-26 15:16 , Jeff Findley wrote: ... Once Starship/Super Booster is flying to earth orbit, its primary mission will be Starlink satellite deployment. Yes you can keep flying up to 60 Starlink satellites at a time on Falcon 9 (more polar orbits will either have less satellites or require Falcon Heavy launches), but when the goal is on the order of 12,000 satellites (by the mid 2020s), that's at least 200 Falcon/Falcon Heavy launches in a few short years! If we guess those launches cost on average $50 million each, that's $10 billion in launch costs just to get the initial constellation up and running! According to Wikipedia, $10 billion is indeed the Starlink cost estimate. But that $10 billion is not just launch costs, but rather total system cost from designing the thing to building all the satellites to deploying them to required ground stations. And keep in mind the lifetime of these satellites is relatively short (from memory something like 3-5 years), so this isn't a "one time" thing. I think that lifetime refers to a failed, dead satellite, in the lower orbits, yes? AIUI working satellites use ion engines that will extend their lifetime. No. 'Lifetime' generally refers to the operating lifespan of the satellite, which for these is 5 years or less. If Starlink is successful, SpaceX will be continuously launching its own Starlink satellites for some time to come. Yes, but if those launches are part of day-to-day Starlink operations, reusing the same launchers, why should they prevent further development aiming at Mars? Because it's going to tie up resources like launch pads, launch management, etc. Once Starlink is complete it takes a Falcon 9 launch per week just to replace satellites that are falling out of orbit. -- "Millions for defense, but not one cent for tribute." -- Charles Pinckney |
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Two Starships in "bolas" rotation
Jeff Findley wrote on Sun, 26 May 2019
08:16:34 -0400: In article , says... And that actually makes sense since all this hardware can be tested out far more easily on lunar missions. Disagree. The hardware will be very different between the two. I agree with Jeff on this one. While some hardware designed for Mars can be tested on the Moon (or on Earth, for that matter) and might be useful for lunar landing and settlement, there are lots of differences. For starters, the landing mode is different. Mars has a thin atmosphere which you want to use to shed as much delta-V as possible. The moon lacks any atmosphere. This also means that in situ propellant production will be completely different. On Mars it will rely on CO2 from the atmosphere. On the moon, it would rely on any water which can be produced from local resources. This means different fuels will be produced (methane on Mars, LH2 on the moon). So even the engines will need to be different. In fact, the difference in atmospheres drives a lot of the engineering, so the hardware just won't be the same at all. Yep. This is why Blue Origin's Blue Moon lander is an LH2/LOX vehicle. It's specifically intended for lunar work. Meanwhile, Starship can also do lunar work but does so by refueling in LEO just like it would for a Mars mission and then NOT requiring a refueling at the Moon to take off and get back to Earth. Second, power generation challenges are different. The long lunar night makes for a large electricity storage requirement. Mars night is much shorter. Mars dust storms provide a challenge for solar arrays. The moon has no dust storms, but does have dust which can be kicked up by human and robotic activity and then stick to surfaces via static electric forces. I don't think anyone is seriously planning on solar for either Moon or Mars. Blue Origin is planning to use hydrogen fuel cells run by boil off from the Lander Element LH2 tank so as to get through that two weeks of frigid night on the Moon. I think Mars settlements are expected to use small nuclear reactors like KRUSTY. Once on the surface of either the Moon or Mars I would expect that Starship would deploy one or more of these for 'shore power'. snip If you want to go to Mars, go to Mars. Going to the moon first is largely a distraction because most of that "experience" gained will be thrown out and nearly everything will need to be re-engineered specifically for the Martian surface environment. I want to go to both and I think Starship is the only feasible system being talked about that can do that. After all, ships that return from Mars need SOMETHING to do until the next conjunction. There is a push within NASA to refocus on the Moon and a lunar base, by any means possible. If that means contracting with private enterprise to do it, so be it. We will have to wait and see how Starship does in this regard. Clearly, especially since the current NASA plan of record doesn't include Starship in any meaningful way. It still relies heavily on SLS/Orion, so we will be limited to one crewed mission per year. That's pretty weak sauce considering how "close" the moon is. Starship doesn't fit their desired architecture. Once they admit that Starship is real, all their plans and hardware go into a cocked hat. If you think the graphic Musk showed of Starship docked to ISS looked a little silly, imagine the same thing with the much smaller Gateway. We are along a familiar trajectory here. Same one as was taken for recoverable Falcon 9 stages. I think Starship will focus on P2P suborbital trajectories first to establish launch and return procedures that must work anyway. Only if they can find a paying customer. Such flights without Super Booster would be severely limited in P2P range. All P2P promotional videos made to date show Starship being lofted by Super Booster. I personally think we'll see Starship only flights for testing, but nothing else. I'm inclined to agree. The big stumbling block for P2P, though, is having all the facilities on the ground built to support it and getting through the regulatory hurdles. Then a push to orbit, then a push beyond. I personally think the "push beyond" will take a very long time. Once Starship/Super Booster is flying to earth orbit, its primary mission will be Starlink satellite deployment. Yes you can keep flying up to 60 Starlink satellites at a time on Falcon 9 (more polar orbits will either have less satellites or require Falcon Heavy launches), but when the goal is on the order of 12,000 satellites (by the mid 2020s), that's at least 200 Falcon/Falcon Heavy launches in a few short years! If we guess those launches cost on average $50 million each, that's $10 billion in launch costs just to get the initial constellation up and running! It takes a Falcon 9 launch every week just to maintain things once they're up. However, I disagree with you. I think you'll see "push beyond" in parallel with satellite deployment. Remember, these are fast turnaround reusable vehicles. And keep in mind the lifetime of these satellites is relatively short (from memory something like 3-5 years), so this isn't a "one time" thing. If Starlink is successful, SpaceX will be continuously launching its own Starlink satellites for some time to come. Yep. They're going to have to replace something like 2500 satellites a year once the full system is up. SpaceX needs Starlink for the potential revenue to attract investors to develop Starship/Super Heavy. But SpaceX also needs Starship/Super Heavy to launch and maintain the Starlink constellation. You're starting to make this sound like trying to fly by tugging on your own bootstraps. SpaceX has gotten over a billion in investment and it is ALL going to StarLink (and none to Starship/Falcon Super Heavy). Mars is still Musk's ultimate goal, but Starlink will need to come first in order to provide the massive cash flow needed to turn Starship from a cargo launcher into a true crewed spaceship capable of performing an actual Mars mission. IMHO, of course. While I think Musk is overly optimistic (as usual), I think you are overly pessimistic. I'd bet on a manned Mars mission before 2030 with the potential for lunar missions before that. -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
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Two Starships in "bolas" rotation
JF Mezei wrote on Sun, 26 May 2019
23:10:24 -0400: On 2019-05-26 20:24, Fred J. McCall wrote: your own bootstraps. SpaceX has gotten over a billion in investment and it is ALL going to StarLink (and none to Starship/Falcon Super Heavy). SO now, you agree there are investors for the BFR/BFS project? Do you not read ****ing English? Which part of "it is ALL going to StarLink" is it that you think says it is going to Starship/Falcon Super Heavy? You blasted me in the not distant past for saying investors in BFR/BFS expect to see return on investment and want a realistic project that doesn't constantly change. Yes, and I'm blasting you now for not being able to read simple declarative English sentences. Which part of "none to Starship/Falcon Super Heavy" is it that you think indicates some is going to Starship/Falcon Super Heavy? -- "Ignorance is preferable to error, and he is less remote from the truth who believes nothing than he who believes what is wrong." -- Thomas Jefferson |
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Two Starships in "bolas" rotation
On Sun, 26 May 2019, Fred J. McCall wrote:
Jeff Findley wrote on Sun, 26 May 2019 And keep in mind the lifetime of these satellites is relatively short (from memory something like 3-5 years), so this isn't a "one time" thing. If Starlink is successful, SpaceX will be continuously launching its own Starlink satellites for some time to come. Yep. They're going to have to replace something like 2500 satellites a year once the full system is up. A huge investement that has to constantly tread water? Insanity! |
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