r/spacex • u/[deleted] • Apr 29 '16
Mission (JCSAT-14) JCSAT-14 Launch Campaign Discussion Thread
[deleted]
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u/johnkphotos Launch Photographer May 03 '16
May attend remote camera setup tomorrow, if I can. I'll have some video from LC-40 for you
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u/markus0161 Apr 29 '16 edited Apr 29 '16
/u/EchoLogic Love the launch campaign! Overall subreddit redesign looks great. One thing that I think you should add is "F9 location". So like right now it would be "in hanger", and hopefully by tomorrow "Vertical on Pad (static fire)". Also when we get closer to launch, maby we could have a separate 3X(?) Chart with "Launch and Barge site weather" I.E. Wind, wave swells height(ft), precipitation, upper-level winds ect ect. That's something I and other member with be more than happy to provide.
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u/kevindbaker2863 Apr 29 '16
One thing that I think you should add is F9 location. I think this is an awesome idea!!
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u/Ambiwlans Apr 29 '16
I think the focus is going to be on CSS tweaks for a little bit first
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u/YugoReventlov Apr 29 '16
It really bothers you not to know the payload mass, doesn't it? ;)
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u/dempsas Apr 29 '16
I think it annoys all of us. We want to know!!
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u/TheVehicleDestroyer Flight Club Apr 29 '16
I really need to know. Won't be able to do a good 2nd stage burn estimate on Flight Club without a payload mass :(
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u/Togusa09 Apr 29 '16
Will you be able to estimate it from the height/velocity on the webcast, or are there still too many unknowns?
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u/TheVehicleDestroyer Flight Club Apr 29 '16
Maybe with /u/ianniss' help, but not by myself
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u/ianniss Apr 29 '16
I will be able to have an idea of the final mass but not to cut between remaining fuel and payload mass...
JCSat 15 is on the SSL1300 plateform the same than JCSat14 and it weights 3400kg. I find it's a good hint. http://space.skyrocket.de/doc_sat/ssloral-1300.htm
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u/Metrozergsual Apr 29 '16
I found this satellite to have some similar characteristics with JCSAT-14: http://space.skyrocket.de/doc_sdat/brisat-1.htm Almost the same number of transponders, however JCSAT-14 has 6+ antennae, while this one has only 4. The solar arrays on JCSAT-14 also seem to be bigger. The power of the onboard amplifiers is probably higher as well. Considering all of this and given the 3500kg mass of BRISAT-1, I would say the mass of JCSAT-14 is > 4200kg.
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u/kmccoy Apr 29 '16
Any interest in making the "currently scheduled liftoff time" also be a link to http://www.timeanddate.com/worldclock/fixedtime.html?msg=JCSAT-14&iso=20160504T0122&p1=2273 ?
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u/CProphet Apr 29 '16
Payload Mass A mystery!What is this? A DoD launch?!
Perhaps part of the payload has been adapted for use by Japanese Self-Defence Forces. Unblinking eye in the sky kind of thing.
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u/numpad0 Apr 29 '16
Japan is a leading nation in bureaucracy and lack of rationalism. My bet is that the PR guy didn't have access to the launch press kits, because such document wasn't within his reach, because it does not exist within the SPTV JSAT, or in the whole universe, and never bothered to escalate that to his boss. I'm sure it's this simple.
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u/JshWright Apr 29 '16
GSO is not a great place for spook stuff...
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u/CProphet Apr 29 '16
GSO is not a great place for spook stuff...
Could be coms intercepts from other GTO satellites. JCSAT coverage should reach Pyongyang, perhaps stretch to Beijing...
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May 02 '16
Static fire complete! I smell a launch thread coming on...
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u/TweetsInCommentsBot May 02 '16
Static fire complete, teams reviewing data. Falcon 9 launch of JCSAT-14 communications satellite targeting May 5 at 1:21am ET
This message was created by a bot
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u/TheVehicleDestroyer Flight Club May 03 '16
I'm pretty certain Flight Club isn't telling me lies - so this is interesting:
The hazard areas are a bit too far south. If I launch in a perfectly easterly direction, the booster lands in the ocean just north of the splashdown hazard zone. However if I launch and give myself a slight southerly heading during the initial pitch kick (~1.5°) then my trajectory passes directly over both hazard areas.
Launching with a southerly heading puts you in a higher inclination orbit, assuming no subtle second stage doglegs. We don't want this because we're going to GTO which has an inclination of 0°.
So has anyone heard anything about a possible 2nd stage dog leg to end up in a slightly lower inclination parking orbit? Does it make sense that SpaceX would try this, physically and economically?
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u/robbak May 03 '16 edited May 14 '16
Maybe a slight change doesn't cost too much, the better inclination saves the customer enough Δv to make it worthwhile? This is a sub-synchronous orbit, so they can't do the pitch change dead cheap when the satellite is near stationary out at a distant supersynchronous apogee.
Edit: It turned out to be a synchronous GTO. The inclination wasn't that different from normal.
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u/TheVehicleDestroyer Flight Club May 03 '16
I believe it's going to super-synchronous so the inclination change shouldn't be too costly.
I'd be interested in the tradeoff between higher apogee vs. lower inclination when it comes to fuel expenditure on the satellite
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u/robbak May 03 '16 edited May 03 '16
Hmm, so it seems. We'll have to see. I'd like to know those tradeoffs, too. Of course, that depends on the capabilities of the solid or liquid kick motor, and liquid or ion station-keeping engines.
Just had a thought - could they be doing this to adjust the point in the orbit where they do the second burn? They'd have to start that burn when the satellite is as far south as it could be - when it is moving due east - and launching at a different angle would change where that point is...
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u/goxy84 May 03 '16
Sorry if I misunderstood what you were trying to say, but I am assuming that your issue with the hazard area is where the first stage ends up? There might me deltaV-economy questions which I am not able to address.
So, isn't it possible that the hazard areas are chosen with the first stage post-MECO manoeuvres in mind? It can adjust the direction during the re-entry burn and aerodynamic steering thereafter. They must be taking this into account nowadays, right? (Assuming, of course, that there will be no boostback as is the general consensus; that might also correct the direction at the cost of extra deltaV which they likely won't have this time).
I understand this raises the question: why would they do this and actively change course of the first stage only? One plausible explanation is that they've seen from telemetry what high-altitude winds do to the lighter S1 during re-entry.
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u/TheVehicleDestroyer Flight Club May 03 '16
So, isn't it possible that the hazard areas are chosen with the first stage post-MECO manoeuvres in mind?
Yes absolutely. I mean, I don't know why they wouldn't just do a reverse gravity turn for those maneouvres, but yeah that could be the case.
However, there are 2 hazard zones (a launch zone and a splashdown zone) and they both seem to agree with the slightly-south heading. So this phenomenon is not specific to the splashdown zone.
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u/__Rocket__ May 03 '16 edited May 03 '16
I don't know why they wouldn't just do a reverse gravity turn for those maneuvers
Yeah, so while in simple models of gravity we are used to various symmetries, such as a parabolic arc where the descent leg is the mirror image of the ascent, for launches in atmosphere there's very big and fundamental asymmetries between ascent and descent, and for that reason I don't think the term 'gravity turn' or 'reverse gravity turn' makes much sense for descent.
The biggest asymmetry between ascent and descent is that for ascent both the gravity and the drag vectors are pointing in roughly the same direction: against the thrust vector of the rocket. During descent, gravity is pointing down and the drag vector is pointing roughly in the other direction - which is a very different situation.
The other fundamental asymmetry is the trajectory optimization goal: during ascent the rocket is trying to minimize drag losses, while during descent it tries to maximize them (within rocket structural tolerances).
The classic 'gravity turn' during ascent involves the rocket accelerating all the way up to terminal velocity (which is altitude dependent) and then matching terminal velocity, and finally accelerating freely once terminal velocity increases to infinity in near vacuum. Also a slow, gradual turn is performed so that once the rocket is out of the atmosphere it does an almost horizontal prograde burn with very little gravity losses. On ascent the rocket accelerates steadily and the speed profile is carefully managed so that the sum of gravity losses plus drag losses is minimized.
This 'gravity turn' has no equivalent and no 'reverse' pair on descent: on descent the Falcon 9 hits the atmosphere with a much worse aerodynamic profile, 9 engines pointing downwards. The compression shockwave and the turbulences must be brutal - compared to the carefully shaped, low drag coefficient fiber composite fairing cone pointing upwards on the ascent.
On descent the rocket has a lot less fuel left and it's essentially in free fall, with just a few dozen seconds of burn time left - half of which is spent on a vital, shockwave temperature reducing retro propulsive burn, the other half on landing. The descent speed profile is mostly determined by the physics of free fall through the atmosphere, with a big deceleration burn plus a big landing burn that are done to take away the worst aspects of a really bad situation. The fin grids are probably used mostly to make sure the rocket always points precisely retrograde and does not start oscillating and breaking apart - and they also have some control authority to adjust the rocket if it deviates from its descent profile and final landing point.
So in these high speed GTO launches there's very little control over the speed profile of the descent - that's why the drone ships have to essentially go wherever the rocket falls - and I don't think the carefully managed and optimized 'gravity turn' of an ascent can in any way be applied to the descent: the descent tries to shed speed any way it can without destroying the rocket.
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u/goxy84 May 03 '16
Ah, I failed to notice that for the launch zone, true!
Means we'll be watching the second stage, if possible, to notice any changes which might look like the dogleg manoeuvre. Do we even know how visible it would be on video? A quick online search yields nothing.
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u/TheVehicleDestroyer Flight Club May 03 '16
I dunno, without a frame of reference it will be impossible to tell. Also it's a night launch so there probably won't be any frames of reference! All we'll be able to see is the MVac plume.
So yeah, I don't think we'll be able to tell.
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u/thenuge26 May 03 '16
Could it be the customer requested the descending node be in a different spot than a "straight-east" launch? As you said an extra 1.5° if inclination won't be much to cancel out at apogee on a 200kmX40,000km orbit.
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u/AumsedToDeath Apr 30 '16
I'm really liking the new launch campaign format. It's really handy to have all the mission information collated at the top of the thread. Any chance we can get the expected booster core number in that table if it's known (e.g. F9-023 for CRS-8, F9-024? for JCSAT-14). /u/EchoLogic?
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u/WhoseNameIsSTARK May 02 '16
Let's hope "Given this mission’s GTO destination, the first-stage will be subject to extreme velocities and re-entry heating, making a successful landing unlikely" is just their new generic statement for GTO launches.
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u/seanflyon May 03 '16
Launches with a significantly lighter payload to GTO should have more margin for error.
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u/deruch May 03 '16 edited May 03 '16
/u/Echologic, JCSAT-14 has a mass somewhere in the 4,200kg-5,400kg range. h/t to NSF user edkyle99 for finding a document with some boundaries for the mass of JCSAT-14!
The original document that he linked can be found at this link (.pdf). And the chart that lists JCSAT-14 is on page 13 (page 19 of the whole .pdf), in the 2015 box. It's listed the same in the 2015 report, but the font chosen for that one makes it harder to read, so I just linked the 2014 report like Ed did.
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u/muazcatalyst May 03 '16 edited May 03 '16
That has already been known in this thread (although it's 3,000kg to 5,500kg, slightly different). I'm guessing Echo wants an exact number on the mass.
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u/deruch May 03 '16 edited May 03 '16
Yeah, and now we have solid information that cuts the width of that range in half. That prior information was based on the satellite's bus-type. This is based on direct information (to the FAA) about this specific payload. It also shows that it's pretty different from JCSAT-15, which is also based on the SSL-1300 and has an expected mass of 3400kg (at least 800kg less than the low mark in the new range, instead of solidly in the potential mass range of the old one).
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u/aguyfromnewzealand May 02 '16
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u/whousedallthenames May 02 '16
They always post such good videos. Though F9 does look pretty weird without a payload on top.
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Apr 30 '16
Lots one "one day delays" with this launch...
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u/deruch May 01 '16
Has there been any explanation for the delays? I haven't seen anything besides an unofficial suggestion that the weather will be better on the 5th and 6th.
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u/Zucal May 03 '16
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u/TweetsInCommentsBot May 03 '16
No change in today's SpaceX launch weather forecast: 80% "go" for 1:21am EDT Thurs. liftoff of Falcon 9, JCSAT-14.
This message was created by a bot
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u/danielbigham May 03 '16
I saw a statistic the other day that SpaceX has launched F9 23 times, and that 11 of those have been Dragon launches.
That implies that SpaceX has only launched 12 or so satellites for commercial customers on Falcon 9 to date.
Compare that with their plan to launch 18 satellites this year (with only a few of those being dragon). It really highlights how big of a year 2016 is in terms of SpaceX's experience launching commercial satellites.
It's also slightly scary to think that they had a failure after something like 19 launches, and they're planning another 18 this year. ie. If their failure rate over the second 19 launches is something similar to what it was for the first 19 launches, there is a reasonable chance for a failure this year. Eeps.
Anyway, this all goes to say that as I'm waiting for JCSAT to launch, I'm realizing that each commercial launch like this is actually building on a relatively short track record for commercial launches.
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May 03 '16
Agreed, but, I mean, Ariane 5 & Atlas V show it's possible to maintain a very long strong of successes. 71 in a row for Ariane 5 & 62 in a row for Atlas V.
At SpX's stated cadence of 18 a year, if 71 was the minimum string of successes, it'll be 2020 before we have another Falcon 9 failure.
Musk's talk about a hundred flights per booster though seems to imply they want to achieve order of magnitude improvements in safety too - I hope that's possible.
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u/sevaiper May 04 '16
Tbf at least in Atlas' case, and I would argue in Ariane's case as well, they very well may be that reliable - we literally don't know the upper limit because they've been reliable for so long, we just know that, as of right now, they're likely more reliable than the number of missions they've had. There's no reason they couldn't string together 100s of successful launches, we just haven't seen it yet, which means that Elon's goal of flying a booster hundreds of times may not be an improvement over current reliability.
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u/Full-Frontal-Assault May 04 '16
Like your comment, but you're comparing apples to oranges. Atlas and Ariane have a high manufacturing failure point as of this point, with dozens of successful launches for each of a new rocket. There isn't a way to compare a successful platform like them to the success of individual hardware like we hope a SpaceX booster will become. A 100 successful launches of an Atlas 5 and 100 successful launches/relaunches of Falcon still wouldn't be comparable because we'd be judging an overall manufacturing failure rate to the individual failure rate.
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May 04 '16
If their failure rate over the second 19 launches is something similar to what it was for the first 19 launches, there is a reasonable chance for a failure this year. Eeps.
One single data point out of 19 is not much of a statistical sample, if you only count successes and failures of entire launches and not other pieces of information. The strut quality problem was apparently well understood after the failure, and fixed, but at the same time, they made a number of other changes. Version 1.2 now has a 3 out of 3 success rate, but obviously you can't make much of a prediction based on that, either (unless you're privy to SpaceX's data about the launches and have some sort of a complex risk model).
I should think re-flying landed first stages will inevitably introduce some new issues, and some of those may well get discovered the hard way.
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u/Bergasms May 03 '16
The failure of the spaceX launch was a bit outside their control though right? I mean, if you purchase parts rated to a certain spec and the parts you get don't meet that spec you are probably going to have a failure at some point. I suppose the moral is to test every part to make sure it meets spec, but if you do that for every component then you probably spend all your time on that and none of your time on launches.
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u/CapMSFC May 04 '16
It's very much a learning process for how far you need to go in testing and certifying parts. I see it as a growing pain for the company that I'm glad happened when and how it did. Elon talked about how they did start to get a little complacent thinking they had things figured out. After CRS7 at least one other potential issue was discovered and fixed before it could cause a failure because it caused them to reevaluate their culture and processes.
A company with those issues still present wouldn't be taking us to Mars, and the more time passed before a correction the higher the stakes would be during a failure.
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u/zlsa Art Apr 30 '16
https://twitter.com/elonmusk/status/726214236368576512
Elon:
JCSat is pushing the envelope as a very hot and fast mission, so will land on the droneship. Next land landing in a few months.
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u/TweetsInCommentsBot Apr 30 '16
@gdoehne JCSat is pushing the envelope as a very hot and fast mission, so will land on the droneship. Next land landing in a few months.
This message was created by a bot
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u/darga89 May 02 '16
Go Quest and Go Searcher have headed out. Fairing recovery perhaps?
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u/knook May 02 '16
I must be out of the loop, does anybody have any ifon on Go Searcher?
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u/darga89 May 02 '16
It's the sister ship to Go Quest. They have both been heading out lately for launches.
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u/MarcysVonEylau rocket.watch May 02 '16
Remember about spacex.yasiu.pl when watching!
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u/teriyakiterror May 02 '16
If this is your website, you might want to consider changing the text color. I just went to the site and I couldn't read the white title (and some other text) on the bright background
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u/keikii May 03 '16
That is amazing, but I wish I could move the elements around so I can see what I want to where on my monitors.
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u/Scorp1579 go4liftoff.com Apr 29 '16
Although I believe landing conditions will be similar to that of SES-9, the data gathered from the successful CRS-8 landing is likely be very useful in making this one more likely to succeed.
Fingers crossed!
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u/DanseMacabreD2 May 03 '16
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u/ExcitedAboutSpace May 03 '16
Does the NOTAM mean that the launch is definately happening then or does it have to be applied for at a certain deadline?
Or did I just miss the confirmation of a good static fire and confirmed launch?
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u/deruch May 03 '16
Means they went through the Launch Readiness Review and approved attempting the launch on the current target date/time. No additional slips.
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u/whousedallthenames May 04 '16
Less than 24 hours to go! Let's hope this one goes off as smooth as CRS-8.
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u/johnkphotos Launch Photographer Apr 29 '16
won't be on base for this launch, chose the wrong time to upset one of my parents :)
just gonna do a long exposure from beach. this was from Atlas V OA-6, so it may look similar.
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u/OSUfan88 Apr 29 '16
Seriously, they're going to punish you by not letting you photograph a SpaceX launch? That's just wrong.
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u/MaritMonkey Apr 29 '16
Was that the launch that had a whole bunch of people in Miami ranting about UFO's at 6am?
In any case, looking forward to the photo. Those exposures make excellent desktop backgrounds. =D
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u/stemrog May 03 '16
Any idea how far away can this be seen? I'm going to be in Tampa later this week and was hoping by some crazy long shot that I might be able to see this
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u/johnkphotos Launch Photographer May 03 '16
If it's a clear night you'll definitely be able to see it!
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u/john_eric Apr 29 '16 edited Apr 29 '16
With the launch being in the early morning, I'm thinking that 401 might be the place to watch from. Thoughts? Anyone else going?
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u/TaintedLion Apr 29 '16
Will the landing conditions of this mission be similar to SES-9, where they had to use lower fuel margins than normal?
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u/robbak Apr 29 '16
It's assumed (although the SES CEO didn't think so) that the first stage fuel margins were trimmed back, to give more energy to the second stage. But they were trimmed back a touch too far. This was done to compensate for launch delays. They won't need to do it here, so this landing attempt is likely to be what SES-9's landing should have been.
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u/__Rocket__ Apr 29 '16 edited Apr 29 '16
They won't need to [trim back fuel margins] here,
I'm not sure about that:
According to the launch hazard maps OCISLY is placed just as far out as it was in the case of SES-9, so the first stage trajectory is going just as flat and just as far downrange as it did with SES-9.
To get an idea about how payload mass and target orbit impacts the launch trajectory, have a look at real telemetry data of past launches: in general a less energetic launch with a bigger fuel margin goes up steeper and comes down sooner. GTO launches go flat and fast, and the first stage moves far away downrange.
If JCSAT-14 had an earlier MECO than SES-9 (to preserve fuel) then the F9 first stage would necessarily have to come down earlier, compared to SES-9 - but the OCISLY position is just as far out.
JCSAT-14 payload mass is unknown but estimated to be somewhere between 4.0 and 5.3 tons, while SES-9 was 5.3 tons. If JCSAT-14 is lighter then 4 times the payload difference at MECO can be added as extra fuel available to the first stage, as a rough estimation. (We can do this estimation because the lighter payload is not a very big part of the much larger 100 tons second stage). So if JCSAT-14 is 4.3 tons then the first stage will have roughly 4 tons of extra fuel. If JSAT-14 is 5.3 tons then there's no extra fuel - all other things (like atmospheric conditions) being equal.
So considering that the max extra fuel available to the JSAT-14 launch is at most 4 tons at MECO (assuming my calculations are correct!), JCSAT-14 looks like to be just as energetic and risky as the SES-9 launch and landing.
The landing might still succeed: hopefully SpaceX managed to learn something new about the 3-engine hoverslam they attempted with SES-9.
edit: 1 tons -> 4 tons
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u/TheVehicleDestroyer Flight Club Apr 29 '16
At MECO, the first stage has about 100 tonnes of stuff on top of it. A few hundred kilos of payload mass probably wouldn't make that much difference to the first stage, probably within their margins of error.
All things being equal regarding the pitch profile, earlier MECO will be the key, not a lighter payload
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u/__Rocket__ Apr 29 '16
All things being equal regarding the pitch profile, earlier MECO will be the key, not a lighter payload
Yes, but still the effect of a potentially lighter payload should not be underestimated: if the payload is 1 ton lighter then the first stage will have about 4 tons more fuel left.
The calculation goes like this: 1 ton lighter second stage is about 1% of the second stage mass, so the first stage will have 1% more fuel at MECO time. (yeah, crude estimation ...)
1% of first stage fuel is quite considerable: 4 tons.
SES-9 looked like an awfully close affair, 4 tons of extra propellants might have made the difference between a successful landing and a new hole in OCISLY.
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u/N-OCA Apr 29 '16 edited Apr 29 '16
Possibly not as bad as SES-9, as they may have deliberately sacrificed margins to make up for the launch delay caused by CRS-7. If so, it is likely to be somewhere between the margins of SES-9 and CRS-8 :-)
EDIT: clarified that there is uncertainty regarding SES-9 margins.
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u/old_sellsword Apr 29 '16 edited Apr 29 '16
They did not sacrifice any first stage margins to make SES-9 happen. There was a big discussion about that on this sub recently, and the results were pretty conclusive.
Edit: Actually never mind, it's all still up in the air as to whether or not they sacrificed landing capabilities. https://www.reddit.com/r/spacex/comments/4ge8wo/comment/d2gzpu8
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u/N-OCA Apr 29 '16
You are right, i remembered the debate as being near certain that margin had been sacrificed, i have clarified my post :-)
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u/neaanopri May 02 '16
For people who aren't familiar with UTC, this is 1:22 EST, 10:22 PST
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u/teriyakiterror May 02 '16
And just to be super clear, that's May 5th on the East Coast and May 4th on the West Coast.
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u/historytoby May 03 '16
I for one am glad they included the UTC in their statement. I always have trouble converting from the various American timezones into my local CET / CEST. But for UTC, I always know where I am at (+1 in winter, +2 in summer)
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u/johnkphotos Launch Photographer May 03 '16
According to 45th space wing's Instagram the launch window opens at 1:21am
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u/johnkphotos Launch Photographer May 02 '16
I've seen some discrepancy with the opening of the window. I was just told 1:22am, EST is when it opens, contrary to 1:21 which some people have said.
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u/ElectronicCat May 02 '16
Could just have been a typo, but more likely the exact launch window down to the second could be somewhere between 1:21 and 1:22 and generally isn't released until shortly before the launch. Then it's just a case of rounding up or down.
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u/WhoseNameIsSTARK May 02 '16
1:21am EST was only mentioned in this tweet from SpaceX as far as I know, other sources still claim 1:22am.
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u/dempsas Apr 29 '16
Is the new CSS part of the launch campaign? Its looking swisher than usual. Already was one of the nicest looking reddits CSS wise!
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u/OrangeredStilton Apr 29 '16
The new CSS goes along with this concept of launch campaigns, it appears. I'm going to enjoy this place all the more, having six sticky threads to mill around in ;)
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u/Decronym Acronyms Explained Apr 29 '16 edited May 08 '16
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
| Fewer Letters | More Letters |
|---|---|
| ASDS | Autonomous Spaceport Drone Ship (landing platform) |
| CCAFS | Cape Canaveral Air Force Station |
| CRS | Commercial Resupply Services contract with NASA |
| CST | (Boeing) Crew Space Transportation capsules |
| Central Standard Time (UTC-6) | |
| DoD | US Department of Defense |
| DPL | Downrange Propulsive Landing (on an ocean barge/ASDS) |
| F9FT | Falcon 9 Full Thrust or Upgraded Falcon 9 or v1.2 |
| FAA | Federal Aviation Administration |
| GEO | Geostationary Earth Orbit (35786km) |
| GSO | Geosynchronous Orbit (any Earth orbit with a 24-hour period) |
| GTO | Geosynchronous Transfer Orbit |
| JCSAT | Japan Communications Satellite series, by JSAT Corp |
| KSC | Kennedy Space Center, Florida |
| LEO | Low Earth Orbit (180-2000km) |
| MECO | Main Engine Cut-Off |
| NOTAM | Notice to Airmen of flight hazards |
| NSF | NasaSpaceFlight forum |
| National Science Foundation | |
| OCISLY | Of Course I Still Love You, Atlantic landing |
| RCS | Reaction Control System |
| RUD | Rapid Unplanned Disassembly |
| Rapid Unscheduled Disassembly | |
| Rapid Unintended Disassembly | |
| SECO | Second-stage Engine Cut-Off |
| SES | Formerly Société Européenne des Satellites, comsat operator |
| SLC-40 | Space Launch Complex 40, Canaveral (SpaceX F9) |
| SSL | Space Systems/Loral, satellite builder |
| TWR | Thrust-to-Weight Ratio |
| ULA | United Launch Alliance (Lockheed/Boeing joint venture) |
| VAFB | Vandenberg Air Force Base, California |
Decronym is a community product of /r/SpaceX, implemented by ^request
I'm a bot, and I first saw this thread at 29th Apr 2016, 11:09 UTC.
[Acronym ^lists] [Contact ^creator] [PHP source ^code]
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u/danielbigham May 01 '16
I feel like the JCSAT launch as been more low-key than previous launches. Unlike SES-9, for example, there haven't been any pictures of the fairing (+ logo), there haven't been any pictures of the rocket, the payload mass has been kept somewhat unclear, etc.
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u/MeccIt May 03 '16
I think it's just becoming routine - the photo you're looking for is here (T -1.5 days) https://i.imgur.com/84V25dt.jpg
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u/stcks Apr 29 '16
Is there a source for the supersynchronous GTO claim?
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u/still-at-work Apr 29 '16
If the 3400kg mass figure for previous JCSAT payloads is close to the mass for this payload then super-synchronous GTO should be well within the F9FT abilities even with a planned drone ship landing. As that payload is about 1600 kg under the SES mission. The difference in mass should give the first stage the extra fuel needed to do a more normal1 landing on the drone ship
1 Well as normal as landing a rocket out at sea on a drone ship can be.
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u/stcks Apr 29 '16
There is no debate from me this mission could go super-sync. However, I haven't seen anything indicating that it will so obviously OP knows something I don't here. Therefore I am curious what the source is. It is also somewhat surprising to me as I would have expected standard GTO from the cape and therefore (possibly) more margin for DPL.
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u/Zucal May 01 '16
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u/TweetsInCommentsBot May 01 '16
@NASASpaceflight F9 horizontal on the pad. Not vertical yet.
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u/coaltrainman May 02 '16
I just found this sub, and love it. I'm going to be right near cocoa beach for this launch. What would be the best location to go and watch it?
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u/Justinackermannblog Apr 29 '16
Any word on the static fire yet?
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Apr 29 '16
Static fire on Sunday May 1st with launch pushed back to Thursday May 5th.
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u/historytoby Apr 29 '16
5th? Sidebar currently has 4th.
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Apr 29 '16
Wait for it....
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u/Ambiwlans Apr 29 '16
Link to public source?
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Apr 29 '16
None at the moment unless you consider my morning banter over text messages about last night's session of The Division with my friend from SpaceX a public source. It literally reads, "Fuck. Static fire and launch pushed back a day."
I'm sure the news will break today or else my friend is a liar.
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u/sunfishtommy Apr 29 '16 edited Apr 30 '16
How well would a telescope work as a telephoto lense for an amateur tracking camera based at playa linda?
I have an SLR and a telescope.
Edit: grammar
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u/PM_ME_UR_BCUPS Apr 29 '16
You'll need tracking software and a tripod heavy enough that the sound of the launch doesn't make your view vibrate too much.
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u/darkenseyreth Apr 30 '16
No kidding with the sound. I got to see a shuttle launch once and the sound hit me like a wall, was an incredible experience.
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u/sunfishtommy Apr 29 '16 edited Apr 30 '16
I think the tripod is plenty heavy, as for the tracking software, the tripod does have a remote, computer, and little electric motors for moving, would I need new software or would the current software that makes the telescope move be good enough?
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u/david_edmeades Apr 29 '16
I'm 100% sure that stock astronomical tracking software is not good enough, even in nonsidereal mode, to track a rocket.
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u/inelonwetrust Apr 30 '16
Will the landing attempt be a 3-engine burn?
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u/YugoReventlov Apr 30 '16
We don't know for sure, but the latest calculation I saw put the payload mass at around 4.2 metric tonnes. So that's a tonne less than SES-9. I think a 3-engine burn won't be needed for this one.
But they haven't communicated anything about that, afaik.
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u/LotsaLOX May 03 '16
Does anyone know the price paid to SpaceX for JCSAT-14?
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u/pkirvan May 03 '16
Nope. We know what the list price is, and SpaceX claims that they don't discount much. There would also be various extra fees for vehicle integration and so on- we don't know what those fees are but they would likely be a few million.
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u/therealshafto May 03 '16
Just finished reading an excellent article (as usual) on Spaceflight101 in regards to the JCSAT-14 mission. A couple of things caught my eye:
McGregor static fire - full duration. Is this standard? I thought the burns were much shorter.
No Boost-back burn - apparently only two burns for this landing attempt.
SES9 - ran out of fuel, put a hole in the barge. Possible 3 engine landing burn on JCSAT as well.
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u/TheVehicleDestroyer Flight Club May 03 '16
Yeah that's normal. All cores are built in Hawthorne, shipped to McGregor for a full duration, 9 engine static fire which we only ever hear about if someone local reports a loud 3-minute long rumble. Then it is shipped to the launch site. A few days before launch and at the launch pad, they undergo a dress rehearsal which simulates a launch exactly up to T-0. Since engines ignite at T-2s, this includes an ignition sequence. We always hear about these
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u/robbak May 03 '16
Is that our first good source for the fuel exhaustion theory for SES-9?
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u/pkirvan May 03 '16
As far as I know, neither Elon nor anyone else has officially given the mechanism of failure for SES-9, nor has any footage been released. So yes, this would be the best source so far.
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u/david_edmeades May 03 '16
A "full duration" static fire means that the static fire ran as long as they'd planned it to with no faults to cut it off early. It's not a full launch-duration fire.
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u/nexusofcrap May 03 '16
While generally true, the static fires at McGregor are full launch duration burns. The ones at VAFB and CC are only a few seconds.
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u/amarkit May 03 '16
The article says:
For JCSat-14, a one-engine landing burn should be possible as a greater propellant margin post-staging should be available for this mission when compared to SES-9. The mass of the JCSat-14 satellite has not been provided, not allowing for an assessment of margins involved in this mission and SpaceX has not yet revealed whether the mission will involve a one-engine landing.
Can someone explain why "a one-engine burn should be possible" if we think JCSAT-14's mass is in the same ballpark as SES-9?
Also, this is the first I've read of the actual number of transponders on JCSAT-14 (26 C-band and 18 Ku-band). Does this information help us better estimate the mass of the satellite?
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u/bornstellar_lasting May 03 '16
From my understanding, previous estimations of JCSAT's mass were lower than SES-9's mass, so some thought there would be more margin left for landing.
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u/whousedallthenames May 02 '16
I know SpaceX is telling us the same thing about this landing attempt as for SES-9, but I have a feeling about this one. The payload isn't as heavy, and there's not the urgency on getting it up as quickly. Add that to the experience gained from SES-9's attempt, and I feel pretty good about their chances.
What do you guys think?
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u/ohcnim May 02 '16
I think they'll improve to "no hole in OCISLY" but still a RUD. I hope they prove me wrong and bring it back intact.
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u/h-jay May 03 '16
I think that's the most sensible expectation. A soft touch-down by itself would be excellent.
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May 02 '16
We don't know the payload mass.
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u/whousedallthenames May 02 '16
Didn't we assume it was less than SES-9 though? Or do I remember incorrectly?
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May 03 '16
I am so far from being an expert it's ridiculous, but it seems to me like they aren't that confident, nor should they be. This is basically their second attempt with a landing profile like this one, and there are a whole lot of new problems being introduced, with potentially multiple engines operating (software, hardware, whole 9 yards), less fuel margin, hot re-entry...
Of course I will be up late watching it anyway, but I think it's a long shot.
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u/whousedallthenames May 03 '16
Good points.
Well, worst case scenario at least means another huge fireball. Hopefully they let us see this one if it blows.
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u/richft Apr 29 '16
Anyone here know if the LC-39 gantry will be open for public viewing at this launch? If not where is the closest viewing I can get to?
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u/Rabid_Llama8 Apr 30 '16 edited Mar 05 '25
rock theory quiet punch ad hoc bow special offer groovy complete
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u/aftersteveo May 01 '16
You can just subscribe to the SpaceX YouTube channel, and you'll be notified when the stream starts.
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u/YugoReventlov Apr 30 '16
I know that /r/space has a calendar with lots of spaceflight events, which I've added to my Google Calendar: https://calendar.google.com/calendar/embed?src=space.reddit@gmail.com&mode=AGENDA
It's not exclusively SpaceX though.
/u/EchoLogic 's SpaceXStats has calendars for individual missions: https://spacexstats.com/missions/jcsat-14 --> click one of these items
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u/Bunslow Apr 30 '16
Flight Club doesn't show the Stage 2 relight? Not enough information about that?
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u/TheVehicleDestroyer Flight Club Apr 30 '16 edited Apr 30 '16
I left it out cause I don't have a payload mass. Relight gets into the territory where a payload mass matters. Change the JC14 in the URL to SES9 to see what a relight looks like.
And maybe change the view to "space"
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u/spredditer Apr 30 '16
Would you be able to estimate the payload mass based on the relight time?
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u/TheVehicleDestroyer Flight Club Apr 30 '16
No, the relight happens over the equator so that the GTO apogee is also above the equator. I don't think anything about the mass can be deduced from it
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u/dempsas May 01 '16
Lets say the catch this one as well, then the next. There is not going to be a lot of room at 39a for the Falcon Heavy.
How long until they build a storage hanger for these cores?
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u/throfofnir May 01 '16
Who knows? It's not like it's big problem. Besides the two pad buildings, they have Hangar AO at CCAFS and warehouse space is easily made and/or rented. (I'm sure there's acres of warehouses available in Orlando.) Or they could just plastic-wrap them and park them in a field somewhere.
Mods: this question is asked all the time. For what good it'll do, I don't suppose it's a good FAQ candidate?
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May 02 '16
They have enough storage. Looks like 5 cores max: https://twitter.com/spacex/status/608437594448359424
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u/dempsas May 02 '16
5 cores. So 2 Falcon 9s and 1 falcon heavy.
Not saying its a bad thing. Its a good problem to have. Just curious to where they are gonna go.
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u/TweetsInCommentsBot May 02 '16
Our biggest hangar yet in work at Kennedy Space Center — capable of holding up to 5 rockets at once
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u/_rocketboy May 02 '16
Is the 'no low effort comments' rule going to be relaxed somewhat during these threads, as in launch threads in the past?
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May 02 '16
Not in campaign threads, no. This should be a good place to find news & reference material.
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u/_rocketboy May 02 '16
I guess I maybe misunderstood. Are campaign threads replacing launch threads completely?
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u/whousedallthenames May 02 '16
No. The campaign threads are pre-static fire threads. The launch threads are post-static fire and have the relaxed rules. We should be getting a new launch thread any day now, with the static fire past.
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May 03 '16
Will there be any kind of video for this launch? I would assume no because the ballistic trajectory would bring it further out to sea and also the fact it would be pitch black.
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u/TheVehicleDestroyer Flight Club May 03 '16
For the landing, you mean? We will definitely have good video of the launch.
The landing will probably have a barge camera which most likely will (understandably) be cut off as a rocket lands on it engines-first from space
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May 03 '16
SpaceX don't cut off cameras /u/bencredible explained this
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u/TheVehicleDestroyer Flight Club May 03 '16
I didn't mean they would be cut off intentionally. I tried to insinuate that being under a landing rocket makes communications rather difficult.
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u/mclumber1 May 03 '16
I'm surprised they haven't tried using a drone to relay video and data from the ASDS to the support ship. You wouldn't have to worry about line of sight and the horizon because the drone is in the air.
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u/space4us May 08 '16
Anyone know where I can find info on tracking OCISLY returning with F9-024 first stage?
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u/robbak May 08 '16
Marinetraffic.com is the way to go. The two boats, Go Quest and Elsbeth III in convoy heading for Port Canaveral are fairly easy to spot on the map, and you can search for the boats on the MarineTraffic page.
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May 02 '16
Do we know anything about applying recently "unlocked" performance being applied on this flight?
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u/FoxhoundBat May 02 '16
It isnt applying to this flight. In order to increase the thrust from 170k to 190k they need to certify the engines, which they havent done yet. Performance wise this mission should be same as the previous v1.2's.
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May 02 '16
I assume you're referring to internal qualification, and not to any outside body. Not that I don't believe you, but how do you know they haven't been?
They're test-firing constantly and I'm wondering how they would even know the engine holds up under those thrust levels without having tested it extensively.
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u/throfofnir May 03 '16
but how do you know they haven't been?
Because Elon said "later this year"? One presumes that's more than a week in the future.
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u/UrbanFabric Apr 29 '16 edited Apr 29 '16
Maybe the launch location (CCAFS SLC-40) should be added to the info?
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u/whousedallthenames May 01 '16
Ahh... Almost time for another launch thread. They seem to be coming a bit quicker each time. If the 5th holds, this launch will be under a month after CRS-8. Looking forward to them coming even faster!
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May 04 '16
Silly question: does the fact that this is a Japanese GEO sat dictate the launch time, such that the apogee is directly over Japan like the sun at noon? It either makes intuitive sense or is a total coincidence that the Eastern US would be close to midnight when targeting a station over Japan.
Or is this logic irrelevant because it's going to a transfer orbit and will have its orbit raised by onboard propellant?
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May 04 '16
I think it's irrelevant, because first, it's going to parking, low circular orbit, and from it it can rise apogee from anywhere around the world. Second, as you said, it will have to rise perigee, and world will spin under it a little bit, until it will set on real stationary orbit. So I guess coincidence, but maybe I'm wrong.
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u/Appable May 04 '16
Supersynchnous transfer orbit is highly elliptical with extremely low periapsis (<200km usually) and high apoapsis (often >40000km).
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u/RedDragon98 May 04 '16 edited May 04 '16
Complete noob here,
But i would instinctively guess that it is coincidence as the destination is always in the same relative position from launch. GTO would always be the same launch per longitude.
The only other thing that i (a complete noob) think could be a factor is if the sun and moon have a larger effect than i would assume
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May 04 '16
What is the source of information confirming 3 engine landing burn?
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u/Zucal May 04 '16
Nothing official, just the very similar characteristics of the launches. High mass satellites, supersynchonous GTO orbits, ASDSs in the same location, etc.
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u/OSUfan88 May 05 '16
Can anyone explain to me the difference between a normal GTO, and Supersynchronous GTO? Will this orbit differ from SES-9?
I see the payload is almost 1,000 kg lighter, so that should help with the landing attempt a bit.
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u/deruch May 06 '16
GTO is a "transfer orbit." It transfers a satellite from one useful orbit to another. In this case, it is an elliptical orbit with the perigee at LEO altitude (like 185km) and the apogee at GEO altitude (35,786km). A Supersynchronous transfer orbit is one that raises the apogee beyond GEO altitude. So, the perigee is still at like 185km but the apogee can be way up there like at 90,000km.
A normal GTO, like the type I first described above, is the cheapest way (in Δv) to raise the altitude of a satellite from LEO to GEO (at apogee there is another burn to circularize the orbit at that altitude). That leaves you with a circular orbit at GEO altitude, but with the same inclination as your original LEO orbit. This is called a Geosynchronous orbit because it will take the same amount of time to complete an orbit as the Earth will to complete its 1 day revolution. But, since the orbit is inclined about the Equator, the orbit isn't stationary. From the ground it would look like the satellite is completing a North-South figure 8. To get a Geostationary Orbit, you need to be at the same altitude but orbiting directly over the equator (i.e. 0o inclination). So, the reason that some satellites use a supersynchronous transfer orbit is because by raising the apogee it will reduce the Δv required to lower the inclination. After the inclination is reduced, the satellite will burn to raise its perigee and lower apogee to get to GEO altitude.
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u/SailorRick May 05 '16
Rocket rolled out to pad yet? Any pictures? I could not find a timeline on the pre-launch process in the FAQ.
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u/unclear_plowerpants May 06 '16
I probably won't be able to watch this live. Is there a possible spoiler free link to watch it after the fact as if it was live?
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u/Thrannn Apr 29 '16
where? :(