magnemoe Posted June 20, 2017 Share Posted June 20, 2017 11 minutes ago, wumpus said: I'm sure it's premature, but is there any indication of Raptor/Mars Colonial Ship being integrated vertically or horizontally? The video of it show vertically on pad. No idea how they will move it however. Both after construction and for doing major service on it, minor service will be done on pad but you would have to replace engines for one. Pretty skeptical to landing back on pad, Main issue is that its riskier than landing on legs and any fail and you will loose the launch pad and tower. How heavy will legs on the ITS be anyway compared with landing it into the launch clamps, you would need the attachment points anyway. Quote Link to comment Share on other sites More sharing options...
Skylon Posted June 20, 2017 Author Share Posted June 20, 2017 1 hour ago, magnemoe said: The video of it show vertically on pad. No idea how they will move it however. Both after construction and for doing major service on it, minor service will be done on pad but you would have to replace engines for one. Pretty skeptical to landing back on pad, Main issue is that its riskier than landing on legs and any fail and you will loose the launch pad and tower. How heavy will legs on the ITS be anyway compared with landing it into the launch clamps, you would need the attachment points anyway. I agree. Other than no need for landing legs, there isn't too much that landing on the pad helps with. Landing on the pad is crazy, especially with a rocket that is so big. I wonder if they will ever stretch the booster like they did with the falcon 9, but I suppose they could be overestimating it based on previous experience Quote Link to comment Share on other sites More sharing options...
tater Posted June 20, 2017 Share Posted June 20, 2017 Yeah, landing on the launch clamps seems absurd. Quote Link to comment Share on other sites More sharing options...
tater Posted June 20, 2017 Share Posted June 20, 2017 Weather in FL looks horrid right now, but the predictions for the weekend are surprisingly good. Quote Link to comment Share on other sites More sharing options...
Terwin Posted June 20, 2017 Share Posted June 20, 2017 1 hour ago, Skylon said: I agree. Other than no need for landing legs, there isn't too much that landing on the pad helps with. Landing on the pad is crazy, especially with a rocket that is so big. I wonder if they will ever stretch the booster like they did with the falcon 9, but I suppose they could be overestimating it based on previous experience If you want a fast turn-around(as in hours), landing back on the pad can save a lot of time and remove opportunities for damage to the landed vehicle(especially with how big this booster is expected to be). Refueling and mounting the tanker second stage will need to be done no matter what else you do, but if you are able to remove every other step beyond a quick visual/telemetry inspection, then you can get turn-arounds where the pumping speed of your fuel pipes becomes a major contributor to your ground-time. There was also a tweet earlier in this thread where musk mentions the accuracy of the landing improving with every return. There is also the option of adding heavy-duty shock-absorbers to the launch-clamps to allow a few extra m/s variance in the landing without damage to the booster.(not feasible when they need to be carried with the rocket, but only needing a flame-resistant cover if it stays on the launch-pad) Admittedly, I would not have considered it even plausible a few years ago, but we are currently living in a world where it is no longer remarkable to have the first stage of an orbital rocket to land within a few meters of it's target, be that a pad near the original launch-pad or a barge floating out at sea. Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted June 20, 2017 Share Posted June 20, 2017 1 hour ago, tater said: Yeah, landing on the launch clamps seems absurd. This seems like the least absurd part of the whole setup to me. And by absurd, I don't mean unworkable. Like @Terwin said, just a few years ago landing a 10-story tall rocket booster on its tail from the edge of space sounded pretty absurd. The technology for this kind of accuracy has been around for a long time, the military has made great use of it, and SpaceX probably benefitted from that experience one way or another. Like all technology, it will continue to get better and better. It's also worth noting, that returning stages do have an "oh crap!" mode. The flight path is such that if an engine fails, the stage will land in the water. The landing burn is what puts it on final target. I wouldn't be surprised if they have a further failure mode at this point, that if an engine fails during the landing burn, the remaining controls will steer it away from the pad/barge. Quote Link to comment Share on other sites More sharing options...
tater Posted June 20, 2017 Share Posted June 20, 2017 BTW, Vandenberg static fire is today at 1:30 pm local time. Quote Link to comment Share on other sites More sharing options...
magnemoe Posted June 20, 2017 Share Posted June 20, 2017 2 hours ago, Terwin said: If you want a fast turn-around(as in hours), landing back on the pad can save a lot of time and remove opportunities for damage to the landed vehicle(especially with how big this booster is expected to be). Refueling and mounting the tanker second stage will need to be done no matter what else you do, but if you are able to remove every other step beyond a quick visual/telemetry inspection, then you can get turn-arounds where the pumping speed of your fuel pipes becomes a major contributor to your ground-time. There was also a tweet earlier in this thread where musk mentions the accuracy of the landing improving with every return. There is also the option of adding heavy-duty shock-absorbers to the launch-clamps to allow a few extra m/s variance in the landing without damage to the booster.(not feasible when they need to be carried with the rocket, but only needing a flame-resistant cover if it stays on the launch-pad) Admittedly, I would not have considered it even plausible a few years ago, but we are currently living in a world where it is no longer remarkable to have the first stage of an orbital rocket to land within a few meters of it's target, be that a pad near the original launch-pad or a barge floating out at sea. I see some issues with landing on the clamps, first is the need for accuracy, you can not miss, you can also not change your mind during the final braking burn. 50 cm off and you crash on an pad you might be 10 meter off and no issues. So landing on clamps will work most of the time but with too low reliability. Worse you lose tower and lots of other structure on fail, so your reliability need to be larger than 99%. Landing on an pad and you can lose some stages, you might even use up the fuel carriers, a in use old boosters until break. That is an benefit of spacex, they are free to lose hardware, feel that NASA play a bit too safe, then you use lots of money developing an mars rover, why only send one, I assume the development cost is far higher than the construction and launch cost. Sending multiple probes also let you lose some Quote Link to comment Share on other sites More sharing options...
tater Posted June 20, 2017 Share Posted June 20, 2017 Static fire accomplished. Quote Link to comment Share on other sites More sharing options...
sojourner Posted June 21, 2017 Share Posted June 21, 2017 I could see a development of the "roomba" used on the barges as a landing pad that "centers" itself on the incoming ITS booster. It would obviously have to be much bigger than the current roomba and you would have to be careful to avoid a feedback loop of the roomba trying to center and the booster also trying to center, but it makes sense to work it out for that last few feet of landing. The key there would be to have the booster ignore the roomba and focus on a fixed landing point while the roomba is focused on lining up with the hardpoints on the booster to grab it. Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted June 21, 2017 Share Posted June 21, 2017 (edited) 9 hours ago, tater said: Yeah, landing on the launch clamps seems absurd. Unless you prepare a secret private facility somewhere on a tropical island. Let me suggest a name for the future craft: Moonraker. Edited June 21, 2017 by kerbiloid Quote Link to comment Share on other sites More sharing options...
Streetwind Posted June 21, 2017 Share Posted June 21, 2017 Here are some words from Iridium CEO Matt Desch on the topic of how Iridium thinks about flying on reusable rockets right now. Salient parts: Quote Desch said there are three criterion by which Iridium would decide whether to use a pre-flown rocket: schedule, cost and reliability — of which schedule is the most important. “Would [pre-flown rockets] improve the current launch plan that I have with brand-new rockets that I’ve basically contracted for a number of years ago and have budgeted for and have paid for?” Desch asked. “That’s the first thing: will they improve my schedule, because schedule to me is very very important.” Not entirely surprising, considering that fate seems to have conspired to delay Iridium Next as much as possible... two separate launch providers and the satellite manufacturer all failed to be on time. Quote Desch said Iridium views the pro of a lower-cost launch, with reuse, as roughly equal to the con of increased risk from a system that is still being proven. Both the cost savings and the new risk are low, he said. Desch didn’t say how much of a discount SpaceX offered for a pre-flown booster, but said the price needs to come down more in order for it to be convincing. “That may change,” Desch said of the discount, “and I can tell you over the coming months if that changes, as there are additional launches I’ll reconsider that, but right now I think we’ve made the right decision.” In other words, even today SpaceX is still not being aggressive about marketing their flight-proven boosters - looks like they're still in the "validation with select customers" phase. They need more time to nail down the refurbishment process. Quote Link to comment Share on other sites More sharing options...
Nibb31 Posted June 21, 2017 Share Posted June 21, 2017 The problem with landing the booster on the launch clamps is that you need those launch clamps to be mobile, so that you can rotate boosters, move them off of the pad for maintenance and upgrade work. You can't have your launch pad occupied 99% of the time with a single booster. Since your launch clamps have to be mobile, it doesn't make sense to land the booster at the launch pad. If something goes wrong with the landing, it would take out the pad and shut down launches for a while. So even with launch clamps, you want a dedicated landing area, and you need to move your boosters+clamps between the landing site, the maintenance facility, and the launch site. In other words, it doesn't save you any time. The only saving with the launch clamps is the weight of the landing gear on the booster, at the cost of much extra complexity and risk. Basically, the infrastructure is going to be similar to the old Apollo crawlers. Quote Link to comment Share on other sites More sharing options...
tater Posted June 21, 2017 Share Posted June 21, 2017 Yeah, what @Nibb31 says. In addition, due to safety constraints, I'd think they'd have 1 launch window a day for tankers. With a 24 hour turn around, if you had 2 boosters, you'd be golden. Launch ITS on B1. Next day, launch tanker with B2. Next day, tanker is fitted to B1 and flies, etc. Quote Link to comment Share on other sites More sharing options...
KSK Posted June 21, 2017 Share Posted June 21, 2017 (edited) 5 hours ago, Streetwind said: *snip* In other words, even today SpaceX is still not being aggressive about marketing their flight-proven boosters - looks like they're still in the "validation with select customers" phase. They need more time to nail down the refurbishment process. Hmmm. The comments from Iridium looked like a fairly transparent attempt at negotiating a lower launch price, so I'm not sure how much weight I would put on them. But with that said I'm not sure I'd even go as far as you @Streetwind. I'd say they (SpaceX) are in an extended development phase given that we also know that they're working on F9 Block 5, the design of which has presumably been heavily influenced from analyses of their recovered boosters and their one proof-of-concept re-flight of one of those boosters. With that in mind, I'm not sure they'd be wise to spin up the hype machine any further until Block 5 is flying and ideally re-flying. The loss of vehicle last Autumn might have cooled off the marketing efforts as well - if they're still having problems launching brand new boosters then aggressively pushing their used (sorry 'flight-proven') boosters looks a bit premature. Finally, I think we're in a bit of a lull at the moment, in terms of re-use economics. SpaceX (if their President is to be believed) looks like it will see significant savings even at current refurbishment requirements (add grain of salt here since we only have one data point to work with), and presumably will pass some of those savings on to their customers. I don't know whether the current 'flight proven' prices are a genuine commercial rate or whether they're a break-even, or even a loss-leading price to drum up business (and so additional flight data) for re-flown boosters. The potential cost savings are very encouraging but I don't think SpaceX have reached their hoped for step-change in launch costs that would encourage new customers and business models to come forward. Hence there's not a lot of point in going all-out on the marketing since it won't attract new customers (because there aren't any right now) and is likely to just cause eye-rolling or worse from their existing customers. Edited June 21, 2017 by KSK Quote Link to comment Share on other sites More sharing options...
tater Posted June 21, 2017 Share Posted June 21, 2017 Block 5 is supposedly the move from reusable, to more operationally significant reusability. Quote Link to comment Share on other sites More sharing options...
wumpus Posted June 21, 2017 Share Posted June 21, 2017 47 minutes ago, KSK said: Hmmm. The comments from Iridium looked like a fairly transparent attempt at negotiating a lower launch price, so I'm not sure how much weight I would put on them. But with that said I'm not sure I'd even go as far as you @Streetwind. I'd say they (SpaceX) are in an extended development phase given that we also know that they're working on F9 Block 5, the design of which has presumably been heavily influenced from analyses of their recovered boosters and their one proof-of-concept re-flight of one of those boosters. I've heard a lot of comments about schedule slippage with Spacex. The catch is that in 6 months they've put 6 satellites in orbit. It reminds me of the Groucho Marx quote "nobody goes there anymore, it's too crowded". Elon time is certainly a thing. But this isn't Elon time, this is a full launch manifest. I'm not seeing anyone else capable of clearing spacex's manifest out. Quote Link to comment Share on other sites More sharing options...
tater Posted June 21, 2017 Share Posted June 21, 2017 Slippage in summer in FL is normal and will never change. It's called "weather." It's not a warped time sense in that case, it just is what it is. 2 pads will help, because when a window in the weather opens, it will allow multiple launches up to the limit of Canaveral range control---it's not really in SX's hands. Quote Link to comment Share on other sites More sharing options...
tater Posted June 21, 2017 Share Posted June 21, 2017 Weather for Bulgariasat-1 launch is still 90% "go" in FL Friday. Vandenberg weather is good for Sunday as well. Woot! Quote Link to comment Share on other sites More sharing options...
Rakaydos Posted June 21, 2017 Share Posted June 21, 2017 (edited) 6 hours ago, Nibb31 said: The problem with landing the booster on the launch clamps is that you need those launch clamps to be mobile, so that you can rotate boosters, move them off of the pad for maintenance and upgrade work. You can't have your launch pad occupied 99% of the time with a single booster. Why not? Sure, it's not how things are done NOW, but if they can get the lifespan and reliability of the booster really up there, like they plan, what's wrong with having 3 boosters on 3 pads, plus a maintinance pad at McGregor, reached by suborbital hop? Rotation can be done by the booster's RCS before landing. Edited June 21, 2017 by Rakaydos Quote Link to comment Share on other sites More sharing options...
tater Posted June 21, 2017 Share Posted June 21, 2017 10 minutes ago, Rakaydos said: Why not? Sure, it's not how things are done NOW, but if they can get the lifespan and reliability of the booster really up there, like they plan, what's wrong with having 3 boosters on 3 pads, plus a maintinance pad at McGregor, reached by suborbital hop? Rotation can be done by the booster's RCS before landing. If the boosters are to spend the time between synodic launch windows inside (sensible in hurricane country), then the SX ground infrastructure needs to be able to move then on the ground anyway. So assume that technology. If they can be moved on the ground, then it's silly to land them on the launch clamps, IMO. The mass penalty of the landing gear translates to tanker logistics, nothing more. Utilized an orbital fuel deport, and pre-launch some or all of the TMI propellant (for a fleet of such ITS vessels, think of the prop depot as a buffer to simplify logistics. Dock the ITS craft, then fly the tankers to the other side of the depot to keep topping it, which is a buffer against slippage in schedule). Honestly, for ITS, an entirely new, and dead level infrastructure would make far more sense. A hanger building level with X pads, and whatever crawler thing that moves boosters. If the gantry has a crane, that means the crawler is easier. get it close enough, move booster with crane like the ITS in the video. Or have no crawler, and have overlapping cranes. Crane 1 moves booster from hanger to point A 2 crane radii from it's post, Crane B moves it from point A to point B, and so on. Quote Link to comment Share on other sites More sharing options...
CSE Posted June 21, 2017 Share Posted June 21, 2017 3 hours ago, Rakaydos said: Why not? Sure, it's not how things are done NOW, but if they can get the lifespan and reliability of the booster really up there, like they plan, what's wrong with having 3 boosters on 3 pads, plus a maintinance pad at McGregor, reached by suborbital hop? Rotation can be done by the booster's RCS before landing. Because each of those early flights that begin the process of proving the lifespan and reliability, has to land its boosters somewhere. Does the first ITS booster to land, land on the launch pad? If not, then you are developing and flight-proving an off-launch-pad landing system for those early flights. Even if the ITS were to be perfection itself right from day one, it would take many flights before SpaceX could know this to be so. To think through whether the ITS might one day, ever, land on the launch pad, one needs to look for a series of steps that progress in that direction from today's proven off-launch-pad rocket-legs technology. Each step needs to be small enough that customers have confidence they're buying the same thing they, and their insurers, are familiar with; at the same time, each step should be an economic improvement over the previous method, so that business and investor goals will keep driving the engineering process forward. My own guess would be that landing a short distance away from the turnaround infrastructure is here to stay - compare aviation today - and that potential turnaround improvements would be either a rocket crawler, to grab the rocket from the landing site or barge and carry it through the refurbishment hall and then to within crane reach of a conventional launch pad; or else various pad crawlers to carry the refurb equipment, with the launch/landing pad being just a reinforced flame trench with some fire suppression infrastructure, and the rocket taking off from its legs, just like landing in reverse. Quote Link to comment Share on other sites More sharing options...
sojourner Posted June 22, 2017 Share Posted June 22, 2017 4 hours ago, CSE said: Each step needs to be small enough that customers have confidence they're buying the same thing they, and their insurers, are familiar with The customers don't care about the fate of the first stage once the second stage has separated. Quote Link to comment Share on other sites More sharing options...
blowfish Posted June 22, 2017 Share Posted June 22, 2017 2 minutes ago, sojourner said: The customers don't care about the fate of the first stage once the second stage has separated. But they do care that the launchpad is going to be ready for their launch when it happens, not damaged or destroyed due to a mishap with an earlier landing. Quote Link to comment Share on other sites More sharing options...
tater Posted June 22, 2017 Share Posted June 22, 2017 I think any ITS infrastructure that includes multiple launches would require multiple pads, regardless. Quote Link to comment Share on other sites More sharing options...
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