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#1260
by
cscott
on 21 Dec, 2015 00:25
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No one has mentioned this yet, but I wonder if the extra time might give SpaceX time to swap out a gse valve or wrap another layer of insulation around a troublesome pipe, something like that. Not *strictly* necessary, but it gives them a bit extra margin on the gse side of things, thus (probabilistically) colder LOX, greater chance of launch in the window, greater landing probability, etc.
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#1261
by
SVBarnard
on 21 Dec, 2015 00:29
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For now.. but eventually the payloads will be worth less than the rocket (otherwise, what's the point of reusability?) and at that point it'll make more sense to save the rocket than the payload.
"But eventually the payloads will be worht less than the rocket" Please will someone explain this to me? Im not a rocket scientist but this is extremely fascinating to me? How could a rocket if it ever becomes reusable be worth more than the payload? Please people I will keep reposting this til its thoroughly explained to me?
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#1262
by
JamesG123
on 21 Dec, 2015 00:37
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"But eventually the payloads will be worht less than the rocket" Please will someone explain this to me? Im not a rocket scientist but this is extremely fascinating to me? How could a rocket if it ever becomes reusable be worth more than the payload? Please people I will keep reposting this til its thoroughly explained to me?
Because if say your payload is a satillite that is worth over its lifetime $500M dollars, that is what its either it cost to develop or build if it is a scientific project, or it is what profit it can generate minus its costs to build and launch.
But, if your launcher costs $50M but you earn $150M per launch, for a profit of $100M, right now the payload is worth more than the rocket. But what if you can launch that rocket 10 times? The rocket is now worth more over the long run than its payload.
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#1263
by
TomTX
on 21 Dec, 2015 00:56
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... they passed the data and the LRR, then not happy again. Bit confusing 
They didn't say they "weren't happy". What I get from the tweet is that they like the landing odds tomorrow better - that's all. I assume that is because the wind gusts at LZ-1 will be half the strength v.s. tonight's wind gusts. Unless there is a compelling reason to launch tonight, I'd make the same choice, especially because of the importance of this landing attempt. Lighter wind gusts means better control authority for the landing attempt. It's a good call.
Minor technical nitpick: If we are looking at wind speeds tomorrow half of today's speeds, the strength (power) of the wind will be one eighth, not one half. Wind power goes up with the cube of the speed.
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#1264
by
CyndyC
on 21 Dec, 2015 01:19
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No one has mentioned this yet, but I wonder if the extra time might give SpaceX time to swap out a gse valve or wrap another layer of insulation around a troublesome pipe, something like that. Not *strictly* necessary, but it gives them a bit extra margin on the gse side of things, thus (probabilistically) colder LOX, greater chance of launch in the window, greater landing probability, etc.
This and another post or two have been the only ones to bring up the ground support equipment. All eyes have been on SpaceX, but according to a comment on another news site, the propellant systems at LC-40 are newly renovated, so not surprising if breaking in the new GSE has been part of the hold up.
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#1265
by
davey142
on 21 Dec, 2015 01:20
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Why can't there be multiple reasons for the delay? Perhaps there was something out of the ordinary during static fire testing. Maybe it wasn't enough on its own to delay the launch but when combined with better landing odds, caused SpaceX to elect to delay by 24 hours.
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#1266
by
meekGee
on 21 Dec, 2015 01:44
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And no-one said:
- Gives launch team a little time to rest after a few hard days, and reflect if launch fever might be operating.
Their Monte Carlo analysis factors in operator fatigue!
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#1267
by
Lee Jay
on 21 Dec, 2015 01:49
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... they passed the data and the LRR, then not happy again. Bit confusing
They didn't say they "weren't happy". What I get from the tweet is that they like the landing odds tomorrow better - that's all. I assume that is because the wind gusts at LZ-1 will be half the strength v.s. tonight's wind gusts. Unless there is a compelling reason to launch tonight, I'd make the same choice, especially because of the importance of this landing attempt. Lighter wind gusts means better control authority for the landing attempt. It's a good call.
Minor technical nitpick: If we are looking at wind speeds tomorrow half of today's speeds, the strength (power) of the wind will be one eighth, not one half. Wind power goes up with the cube of the speed.
The force goes up with the square and the force is probably what's important for control authority. The power is important for wind turbines.
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#1268
by
Danny452
on 21 Dec, 2015 02:02
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"But eventually the payloads will be worht less than the rocket" Please will someone explain this to me? Im not a rocket scientist but this is extremely fascinating to me? How could a rocket if it ever becomes reusable be worth more than the payload? Please people I will keep reposting this til its thoroughly explained to me?
Because if say your payload is a satillite that is worth over its lifetime $500M dollars, that is what its either it cost to develop or build if it is a scientific project, or it is what profit it can generate minus its costs to build and launch.
But, if your launcher costs $50M but you earn $150M per launch, for a profit of $100M, right now the payload is worth more than the rocket. But what if you can launch that rocket 10 times? The rocket is now worth more over the long run than its payload.
When the rocket is reusable Spacex can charge much less for a launch. This makes it worthwhile launching cheaper satellites. The cost of building the rocket stays the same. But the cost of launching it is less and the (average) value of satellite launched is less.
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#1269
by
gregpet
on 21 Dec, 2015 02:32
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"But eventually the payloads will be worht less than the rocket" Please will someone explain this to me? Im not a rocket scientist but this is extremely fascinating to me? How could a rocket if it ever becomes reusable be worth more than the payload? Please people I will keep reposting this til its thoroughly explained to me?
Because if say your payload is a satillite that is worth over its lifetime $500M dollars, that is what its either it cost to develop or build if it is a scientific project, or it is what profit it can generate minus its costs to build and launch.
But, if your launcher costs $50M but you earn $150M per launch, for a profit of $100M, right now the payload is worth more than the rocket. But what if you can launch that rocket 10 times? The rocket is now worth more over the long run than its payload.
When the rocket is reusable Spacex can charge much less for a launch. This makes it worthwhile launching cheaper satellites. The cost of building the rocket stays the same. But the cost of launching it is less and the (average) value of satellite launched is less.
Once regular reusability service is up and running, satellite manufacturers will not have to build as much redundancy into their product since they can be quickly and easily relaunched (thus cheaper satellites). The satellites can also be replaced more often given the cheaper manufacturing and launch (maybe a virtuous circle?)
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#1270
by
Lee Jay
on 21 Dec, 2015 02:40
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Once regular reusability service is up and running, satellite manufacturers will not have to build as much redundancy into their product since they can be quickly and easily relaunched (thus cheaper satellites). The satellites can also be replaced more often given the cheaper manufacturing and launch (maybe a virtuous circle?)
Not virtuous at all if you happen to be worried about space junk (and you should be).
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#1271
by
meekGee
on 21 Dec, 2015 02:41
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But to ground the discussion in the topic of the thread, the decision is not whether to lose the rocket or lose the payload (for a long time now, the payload will remain more important).
The decision is whether to postpone a launch in order to improve the chance of recovering the stage (also known as "the barge go-no-go debate".)
For satellites, the decision is easy, since they're not time-critical - not in the scale of days or weeks.
For ISS supply, initially they'll run into the "every day's delay costs millions" argument, but after a while this will subside, since launch delays happen all the time anyway, multiple times, over weeks and sometimes months, and the ISS survives. So if the rocket is expected to be recovered as a matter of routine, then it won't launch if it can't land.
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#1272
by
a_langwich
on 21 Dec, 2015 03:32
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"But eventually the payloads will be worht less than the rocket" Please will someone explain this to me? Im not a rocket scientist but this is extremely fascinating to me? How could a rocket if it ever becomes reusable be worth more than the payload? Please people I will keep reposting this til its thoroughly explained to me?
Because if say your payload is a satillite that is worth over its lifetime $500M dollars, that is what its either it cost to develop or build if it is a scientific project, or it is what profit it can generate minus its costs to build and launch.
But, if your launcher costs $50M but you earn $150M per launch, for a profit of $100M, right now the payload is worth more than the rocket. But what if you can launch that rocket 10 times? The rocket is now worth more over the long run than its payload.
Hmm, I'm not sure I agree with that accounting logic. If the rocket is damaged irretrievably on the first flight, by this accounting method you are saying you've lost $900M dollars, but in fact you haven't, you can replace it for only $50M by your numbers (+ costs for delays, possibly lost launch opportunities, etc, none of which is likely to approach or coincide with your phantom $900M).
If the landing gear collapses and an airline "totals" an airplane, they aren't in the hole for the entire revenue that airplane would have made over the rest of its career (even assuming such a crystal-ball number could be calculated). They are only out the cost of the airplane (+ costs for delays, possibly canceled flights, etc, none of which would approach the total-future-revenue figure).
More likely, if SpaceX managed to get launch prices down sharply, then it is likely the business case for launching a payload could be closed for much cheaper payloads.
If this is not the case, for example if orbital debris concerns increase costs as quickly as reusability lowers them, or the satcom market saturates and other markets fail to materialize, then demand for launch services will not increase sufficiently with lower prices, and reusability will not be worthwhile.
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#1273
by
Kabloona
on 21 Dec, 2015 03:38
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#1274
by
QuantumG
on 21 Dec, 2015 03:43
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I think the payload on this launch is insured for about $76M.
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#1275
by
a_langwich
on 21 Dec, 2015 03:57
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The decision is whether to postpone a launch in order to improve the chance of recovering the stage (also known as "the barge go-no-go debate".)
For satellites, the decision is easy, since they're not time-critical - not in the scale of days or weeks.
For ISS supply, initially they'll run into the "every day's delay costs millions" argument, but after a while this will subside, since launch delays happen all the time anyway, multiple times, over weeks and sometimes months, and the ISS survives. So if the rocket is expected to be recovered as a matter of routine, then it won't launch if it can't land.
I think the comsat manufacturers would tell you every one of THEIR days costs money, too. But presumably they (like the ISS) have factored in margins for those delays.
In the bigger picture, there is the extremely long backlog of flights that SpaceX is carrying. If the rocket won't launch when it can't land, and if that adds appreciably to SpaceX's inability to launch on a schedule, then "every day's delay costs millions" to them, too. That is, a day here and there seems like no big deal, but if that huge backlog isn't getting worked off because of these self-inflicted delays, potential customers are going to walk past their door and find a competitor.
I don't expect that to happen, of course. It seems likely with a little experience landings would very, very rarely contribute to a delay.
But for the next year, possibly two, it seems to me customers are getting nothing (but delays) from SpaceX's extracurricular activities, and I imagine the bigger customers like SES won't tolerate as much. Orbcomm is paying 1/3 the price knocked off the cheapest rocket around (albeit with a several years long delay, too, right?), so they are presumably happy.
It was uncharacteristically tone-deaf for Elon Musk to tweet what he did, which is why we are all discussing it now. Perhaps he is pretty tired, too.
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#1276
by
Lars-J
on 21 Dec, 2015 04:09
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But for the next year, possibly two, it seems to me customers are getting nothing (but delays) from SpaceX's extracurricular activities, and I imagine the bigger customers like SES won't tolerate as much. Orbcomm is paying 1/3 the price knocked off the cheapest rocket around (albeit with a several years long delay, too, right?), so they are presumably happy.
It was uncharacteristically tone-deaf for Elon Musk to tweet what he did, which is why we are all discussing it now. Perhaps he is pretty tired, too.
There is no reason that you need to voice your disappointmewnt on behalf of the customers.
I'm sure they are quite capable of expressing any frustrations to SpaceX directly.
Believe it or not Orbcomm and SES (and other customers) are FAAAAAR more involved in the SpaceX decision making than we are.
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#1277
by
a_langwich
on 21 Dec, 2015 04:41
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But for the next year, possibly two, it seems to me customers are getting nothing (but delays) from SpaceX's extracurricular activities, and I imagine the bigger customers like SES won't tolerate as much. Orbcomm is paying 1/3 the price knocked off the cheapest rocket around (albeit with a several years long delay, too, right?), so they are presumably happy.
It was uncharacteristically tone-deaf for Elon Musk to tweet what he did, which is why we are all discussing it now. Perhaps he is pretty tired, too.
There is no reason that you need to voice your disappointmewnt on behalf of the customers. I'm sure they are quite capable of expressing any frustrations to SpaceX directly.
Believe it or not Orbcomm and SES (and other customers) are FAAAAAR more involved in the SpaceX decision making than we are.
I'm not voicing disappointment on behalf of the customers, we were talking about the costs/benefits of delaying delivery for the customer in order to achieve landing, and that's a cost. I'm not voicing their concerns for them, I'm describing what I think is the likely outcome of that process. The likely outcome is that SpaceX will focus far more heavily on primary mission execution for SES.
With regard to Musk's tweet, whenever the story from one CEO in a transaction differs markedly from the story of the other CEO, and that difference diminishes the importance of one of the two, that was probably not the ideal tweet. (Assuming the two CEOs aren't in open conflict, like suing each other or trying a hostile takeover.) The PR department (possibly including Shotwell) would probably have preferred giving the impression that primary mission execution was the driving factor for Orbcomm, too.
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#1278
by
OxCartMark
on 21 Dec, 2015 05:00
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I've read some speculation upthread that depletion of the oxygen stores could be the thing that drove this decision. And I've seen where it was speculated that you'd want the stage to come back with the minimum propellent load to increase maneuverability. Another twist on this that makes sense to me is that it could be that they are a bit low on oxygen but do have enough to get a flight and return attempt in. ...But having more oxygen (which could take a day to get) would mean that the stage lands heavier so that on the spectrum of hover-slam the landing dynamics are moved a bit closer to the hover end of the spectrum, allowing just a bit more time for maneuvering and (in this theory 10%) increased probability of success. Recall from the successful Blue Origin landing that their craft was was completely capable of hovering.
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This may be one more of an endless series of repeated answers but the ASDS was supposedly able to hold its position to 3 meters.
This is less than the diameter of the rocket and not significant on the scale of the ~53 meter wide ASDS.
Another ten feet of deck wouldn't have enabled either of the previous landing attempt to succeed.
Weeeel.
To land properly you need to get down at the right vertical, horizontal speeds, in the right horizontal and vertical position.
These are not unrelated problems.
If you relax any constraint, others get easier.
Getting it upright at 0 horizontal speed and 0 vertical velocity is moderately eased - especially if you have an imperfectly tuned control loop - if you add flex to the absolute position.
Weeeel, If you consider the two near misses in which the stage came down a few hundred feet off the ASDS then had to make a quick horizontal divert I'll bet you would have gotten a better result if the control system had been able to say "I'm not horizontally in the right position but I am over a legitimate landing spot so I'll just deal with vertical altitude and vertical component of velocity". Also, when thinking of the 53 meter wide ASDS and 3M position holding capability don't forget that the legs are quite wide when splayed out.
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Allow me to expand on the term "Monte Carlo Analysis". Elon told his team that if they can get the 11 satellites where they need to be and if they car also land the stage in one piece he'd send them all to Monte Carlo for a week. After some discussion among the team members they concluded that they had a better chance of winning the bet on Monday.
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#1279
by
Lars-J
on 21 Dec, 2015 05:01
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But for the next year, possibly two, it seems to me customers are getting nothing (but delays) from SpaceX's extracurricular activities, and I imagine the bigger customers like SES won't tolerate as much. Orbcomm is paying 1/3 the price knocked off the cheapest rocket around (albeit with a several years long delay, too, right?), so they are presumably happy.
It was uncharacteristically tone-deaf for Elon Musk to tweet what he did, which is why we are all discussing it now. Perhaps he is pretty tired, too.
There is no reason that you need to voice your disappointmewnt on behalf of the customers. I'm sure they are quite capable of expressing any frustrations to SpaceX directly.
Believe it or not Orbcomm and SES (and other customers) are FAAAAAR more involved in the SpaceX decision making than we are.
I'm not voicing disappointment on behalf of the customers, we were talking about the costs/benefits of delaying delivery for the customer in order to achieve landing, and that's a cost. I'm not voicing their concerns for them, I'm describing what I think is the likely outcome of that process. The likely outcome is that SpaceX will focus far more heavily on primary mission execution for SES
It's only a short-term cost, but potentially a long term benefit. SpaceX wants to transition to a reusable model which will benefit customers. The customers know this. And if you start to view the whole enterprise from a reusable perspective, it makes a lot of sense to start adjusting the factors in your fly/wait decision tree.
After all, would you have any complaints if a air freight company decided to delay a flight a couple of days if it meant that their aircraft wouldn't crash on the way back? Air freight customers know that air freight would get VERY expensive fast if the aircraft started falling out of the sky instead of being reused.
I'm sure they are quite capable of expressing any frustrations to SpaceX directly.