SpaceX finally nails a droneship landing!

Phuncz

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May 9, 2015
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And that's why we'll still be watching Alien movies for many decades before we can have our faces hugged in real life. #whoneedsreality
 

CC Ricers

Shrink Ray Wielder
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Nov 1, 2015
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Payload was integrated as part of a full test and not a simple static fire. Unfortunately, because the ignition was unintended, the satellite won't be covered by the insurance.

It also took place at the same launch pad that is planned for the first re-use of a previously flown first stage, flight SES-10, so that will very likely be delayed also.
 

EdZ

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May 11, 2015
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Almost all of SpaceX's launches will be delayed due to damage to LC-40. It's their only east-coats pad (for now. The conversion of LC-39A is far from complete) so their only remaining active pad is SLC-4E at Vandenberg on the west coast, and that is only suitable for polar and retrograde launches. All SpaceX's LEO customers, GEO customers, and the CRS flights to the ISS will be on hold until either LC-40 is reactivated or conversion of LC-39A is completed.
 

Cutie DarkFae

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May 18, 2016
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Yeah, this is sad :( SpaceX should bounce back from this, Elon BELIEVES! in Mars, and SpaceX isn't a publicly traded company so there's no stock price to worry about. But it's a serious dent in their reputation :(
 

jeshikat

Jessica. Wayward SFF.n Founder
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Feb 22, 2015
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Yup, so epic:


Less epic was half the questions from the Q&A after the presentation :\
 

EdZ

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Yeah those were awful. So many things to ask about (the low-ratio bells in the centre of the MCT, that ludicrously large window, mircrogravity vs. tethered centrifuge, 'fan' solar arrays vs. more area efficient packings, MCT launch-escape architecture, etc). I guess the r/SpaceX guys couldn't sprint fast enough from the front row to the mic stands.
 

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Shrink Ray Wielder
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I guess the r/SpaceX guys couldn't sprint fast enough from the front row to the mic stands.

Nah, much of r/spacex is also upset about the quality check (or lack thereof) of the questions asked at the panel. Some media personalities like Roosterteeth(!) were apparently there.. I guess the people during the Q&A just wanted to take advantage of the media frenzy.

The whole presentation and video demos make the project sound so impressive yet at the same time they make it look deceptively simple as a scaled up version of their current reusable rocket system. That big window does make me wonder how well it could take possible debris impacts at cruising speeds. Lots of issues to be addressed for the safety of passengers on the way to Mars.
 

jeshikat

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Lots of issues to be addressed for the safety of passengers on the way to Mars.

Yeah, Musk was a bit dismissive of the safety aspects. I think his comparisons of Mars colonization to the early European settlers traveling to The New World is going to be more apt than people would like :p
 

EdZ

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In the impromptu press-only Q&A afterwards, Musk said the MCT engines double as the abort engines.
He did, but non pressure-fed non-hypergolic engines take some time to spin up their turbopumps, bring the chamber up to operating pressure, and ignite before ramping up to maximum thrust (the the Raptor not only has an extremely chamber pressure, but has two independent turbopumps as part of it's full-flow staged combustion cycle). Unlike with Dragon 2, whose Superdraco engines are Hypergolic and pressure-fed - so will ignite and ramp up to full thrust in a few milliseconds just by opening a valve - the MCT would be sitting on a RUD for several seconds before the Raptors could start moving it away (and they would be exhausting directly into the interstage chamber, which risks damaging the Raptors themselves in the enclosed space). Plus several of the Raptors have extended nozzle bells for vacuum use, so these would need to be jettisoned (tricky, you won;t want to add the mass of an explosive cleaver to the nozzle extension), have thrust severely ramped down, to just blast away and hope the flow separation doesn't fire bits of shattering nozzle extension into the adjacent engines.
 

iFreilicht

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Feb 28, 2015
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That big window does make me wonder how well it could take possible debris impacts at cruising speeds.

Did they even say that was going to be a real thing? I imagined that as just being the artists impression to make it look cooler.

He did, but non pressure-fed non-hypergolic engines take some time to spin up their turbopumps, bring the chamber up to operating pressure, and ignite before ramping up to maximum thrust (the the Raptor not only has an extremely chamber pressure, but has two independent turbopumps as part of it's full-flow staged combustion cycle). Unlike with Dragon 2, whose Superdraco engines are Hypergolic and pressure-fed - so will ignite and ramp up to full thrust in a few milliseconds just by opening a valve - the MCT would be sitting on a RUD for several seconds before the Raptors could start moving it away (and they would be exhausting directly into the interstage chamber, which risks damaging the Raptors themselves in the enclosed space). Plus several of the Raptors have extended nozzle bells for vacuum use, so these would need to be jettisoned (tricky, you won;t want to add the mass of an explosive cleaver to the nozzle extension), have thrust severely ramped down, to just blast away and hope the flow separation doesn't fire bits of shattering nozzle extension into the adjacent engines.

Very good points. But SpaceX is already using a design for bells where the vacuum extension is a separate part which is extended after stage separation on their transfer stage on falcon, so maybe they'll just have something like that?

Could there be a way to let the turbopumps run on "standby", generating fuel pressure towards the exhaust without opening the exhaust valve?
 

EdZ

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Very good points. But SpaceX is already using a design for bells where the vacuum extension is a separate part which is extended after stage separation on their transfer stage on falcon, so maybe they'll just have something like that?
The M1Dvac's nozzle extension is welded to the bell (on the second F9 mission where the extension was damaged in transit, they literally took a set of tin-snips to it to trim it off and used excess fuel to counter the loss in efficiency). The RL10B-2 on the Centaur variant used on the Delta IV has a moveable nozzle extension, as does the yet-to-fly Vinci motor.
Could there be a way to let the turbopumps run on "standby", generating fuel pressure towards the exhaust without opening the exhaust valve?
That might be tricky. The turbopumps are driven by full-flow gas generators which cannot operate independently of the pumps, so having the pumps spun up would require effectively pumping fuel and oxidiser out of the nozzle at flight flow-rates (tons per second) but not igniting it. Which would then hit the hot gas-generator exhaust that feeds into the bell, and would probably ignite in a nice kaboom between the first and second stages.
 

jeshikat

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It's not ideal, but is there any alternative when there's just one large upper stage?
 

EdZ

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They had a few delays due to a Helium line on the Strongback, but that has been resolved. Supposedly they've changed their Helium loading procedure to a 'prior proven flight configuration', but as far as I know they've always loaded the Helium once LOX is already partially filling the tank, even prior to the switch to sub-chilled propellants.
 

EdZ

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Iridium NEXT 1-10 is looking good so far: good launch and insertion of S2 into it's parking orbit (will be another ~20 minutes before satellite deployment), good landing of S1 on JRTI.

 
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iFreilicht

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Not called RTFM. Why even watch the stream? :( jk, missed the live stream, going to catch up right now. Good to see everything is back to normal. Also holy smoke, they got a steady stream from the rocket down to the landing? Did they change something about their setup?
 

EdZ

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Also holy smoke, they got a steady stream from the rocket down to the landing? Did they change something about their setup?
This launch was from Vandenberg rather than CCAFS, so maybe they managed to wrangle some time on one of the high-gain tracking antennas there (normally used for ICBM test launches)? They had some beautiful IR tracking shots too.