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Space Transportation

Musk Announces Return-to-Flight Date For Falcon 9 Rocket 114

Rei writes: After being grounded for six months after a strut failure doomed the launch vehicle, Elon Musk has confirmed rumors that SpaceX plans to try for launch again on December 19th, with a static test firing on December 16th. SpaceX will also attempt a landing of their first stage — not at sea, but on land. Lastly, this will be the first launch of a Falcon 9 "Full Thrust" variant, where the propellants are supercooled (with the oxygen just above its freezing point) to increase their density and thus fuel flow and thrust.
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Musk Announces Return-to-Flight Date For Falcon 9 Rocket

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  • just a comment (Score:3, Interesting)

    by Anonymous Coward on Thursday December 10, 2015 @10:03AM (#51094415)

    This return to flight launch is going to be scrutinized by a lot of folks. Hopefully SpaceX has truly determined the problems for the accident. A landing back at the Cape would be awesome.

  • I'm selfishly hoping that they have to scrub the launch on the 19th, I'm going to be in the Orlando area on the 20th and 21st so a delay that allowed me to watch the launch would be awesome.

    • by Rei ( 128717 )

      Here's the 10-day forcast [] - hope that that "chance of rain" on the 19th turns into "thunderstorms and strong upper level winds" ;)

      • by lgw ( 121541 )

        I used to live in Orlando - by my faulty memory one Shuttle launch in five or so went up on the planned day, so this guy's odds are good I think.

        There's an urban legend about how the Cape got picked despite the troublesome weather: someone looked at the average wind velocity there and the daily average was almost zero! (The always-present coastal winds reverse direction in the evening.) Silly, but it would explain a lot.

    • a delay that allowed me to watch the launch would be awesome.

      And the launch is the more boring part! With more notice (and not the week before Christmas!), I would have hopped in the car and motored the boy down to Fla. to see history in the making. Musk is messing with the fanbois - expect a scrub or two. ;)

  • Supercooling (Score:5, Interesting)

    by excelsior_gr ( 969383 ) on Thursday December 10, 2015 @10:46AM (#51094599)

    Aren't supercooled materials actually cooled below their freezing point, but kept in a liquid state? Oxygen "just above its freezing point" is damned cold, but not supercooled. So, which one is it?

    • This is more of an engineering term. If you let Liquid Oxygen sit around at ambient conditions it will be at the boiling point. Getting it colder requires additional systems to lower the temperature.

    • That's exactly what I thought as well. I suspect that there's an arts graduate somewhere in the writing/ editing chain. But no, I didn't bother to RTFA - if it's got this sort of error, and the submitter didn't know enough to catch it for themselves, then it's probably not worth the effort.
  • by Pumpkin Tuna ( 1033058 ) on Thursday December 10, 2015 @10:51AM (#51094629)
    I'm a bit confused. I thought the reason for the barge was because it was pretty far downrange. If they are launching from the Cape and then landing the first stage there too, won't that be a pretty massive turnaround for the first stage? Of course maybe that's why they are going with the "full power" mode. My understanding is that eventually they plan to launch from Texas and land the first stage at the Cape. Is this still what they are saying?
    • by Rei ( 128717 ) on Thursday December 10, 2015 @11:03AM (#51094669) Homepage

      Turnaround is much easier when the stage is nearly empty. First off you have air resistance killing off part of your lateral momentum for you, and you already have altitude. Your stage is vastly lighter as well, having used up most of its propellant and separated from the second stage and payload. Your last kilogram of propellant delivers about 23 times more delta-V than your first (in a way it's kind of problematic - even with just one engine operating and throttled all the way down (70%) it can't "hover", it still has way too much thrust). So turnaround is actually quite doable, if you have a little margin left over. It depends on how heavy your payload is and what sort of trajectory it's being launched to.

    • The first stage is probably all about altitude and so can 'fall' down in place. Only when the craft is above most of the atmosphere does the lateral buildup of speed to orbital insertion begin.

      • Re:landing location (Score:4, Informative)

        by necro81 ( 917438 ) on Thursday December 10, 2015 @01:24PM (#51095509) Journal
        Generally, rockets begin a roll maneuver [] that starts them heading downrange very soon after clearing the tower. For instance, the Saturn V would perform its roll maneuver about 20-30 seconds after liftoff [].

        A huge fraction (90% ?) of the energy an object must gain in order to reach orbit is tangential velocity. By comparison the gain in potential energy from gaining altitude is relatively small.
        • I seem to remember it's 95% for low Earth orbit - theoretically less for higher altitude/slower orbits, but I think most launches aim for LEO first.

          So yeah, the vertical energy needed is a tiny fraction of the total, and since the first stage is typically designed to deliver most of the energy required, it is far more concerned with speed than altitude. They go for altitude quickly mainly to reduce the efficiency losses due to air resistance at high speed.

          • by Rei ( 128717 )

            On the other hand, first stages are limited in how fast they can accelerate due to aerodynamic drag, and they face far more gravity losses. The first stage pays for most of the "losses" that the craft will encounter in its ascent. Lastly, the first stage is only 32% of the total burn time. The most important part of any first stage is to get the craft out of the atmosphere so that the second stage engine can be optimized for vacuum. A first stage can be built for more burn time, but its nozzle - having b

            • Quite right about getting out of the atmosphere being a priority, as I mentioned. That's why they go almost straight up for the early part of the launch - to reduce air resistance as much as possible before putting on speed. But as I recall most first-stage rockets are optimized for the extremely low ambient pressures experienced for the majority of their burn, though obviously there's some compromises made for the sake of the initial low-altitude portion of the flight that can be eliminated for the second

              • by Rei ( 128717 )

                What you call "support force" I call "gravity losses" - see above :). The first stage pays both aero losses and most of the gravity losses, which usually eat up what would otherwise be an additional 1000-1500 m/s delta-V per launch. And the first stage is only a third of the total burn time. And has to be a lot more acceleration-limited during the earliest parts of its flight to minimize aero losses, otherwise you waste even more energy fighting the air (and put more stress on your vehicle at max-Q, which

        • On Space Shuttle the SRBs were purely to gain altitude, which is why they could be recovered near the Cape. It was main engine thrust that took it to orbital speed after SRB staging.

    • They have always publicly said no to the idea of launch in Texas and land at the Cape, at least for now. Musk even detailed that with Falcon Heavy the side boosters would not be able to reach the Cape and the central core would go too far past Florida.

      They have long detailed the plan as try at sea at first and later have it return directly to the original launch area. Although, with some launches of Falcon Heavy they expect to only be able to try landing the central core downrange at sea, if at all.
    • As far as I know, there's still not official word from the FAA approving land-landing, only from the Airforce.

      Also, depending on the mass of the payload, and with the Full Thrust upgrade, they should have enough propellant margin to attempt landing every rocket they send up from now on, but not necessarily enough to redirect all of them back to the launch site.

      And when the Falcon Heavy finally takes flight, while the side boosters should be able to return to the launch site, the central core will probably n

  • One of the things that has frustrated me about SpaceX is it's lack of comprehensive communications about the status of the analysis, what are the corrective actions and what is it's return to launch (and beyond plans).

    I just took a look at their website ( and what do I see? CRS-7 Updates, dated July 20th. Under "Updates", the last entry is July 20th. On twitter, the last time Musk commented on the Falcon issue was July 5th.

    The dearth of timely web page updates and information just

    • by delt0r ( 999393 )
      It is a private company. They are not required to tweet every 15min to keep you entertained. If your a client i am sure it would be a little different.
      • How about ever? I put down a deposit on a Model X, as did my brother. 2 years late and we didn't have a single communication. Not one. Same with PayPal.

    • by k6mfw ( 1182893 )

      SpaceX is it's lack of comprehensive communications

      As others have mentioned it's a private company and like pretty much all have no intention of communicating anything except glowing press releases. There is NASA though they perform a wide range of activities though much of their communications gets bogged down in guvmint bureaucracy.

      Speaking of communications, I sometimes scour the internet for techie stuff on communication systems used by spacecraft but I don't find anything of value. Of course govt and companies are not going to post entire documentati

    • Why Doesn't SpaceX Provide Timely Information?


      Even though FAA rules don't preclude company communication during an accident investigation, ass-covering lawyers insist on a total shutdown anyway.

      And since you're paying your lawyers to cover your ass... you do what they say.

    • You are kidding. Right? Spacex has always given far more information than ula, Boeing, l-mart, ball Northrup , O-atk, etc. They may not give you what YOU want and when you want it, but it is still more information and sooner than others.
  • Hopefully they truly uncovered the issue in the launch vehicle, and don't suffer any more mid-launch explosions. Aside from that, the part that interests me is the continued testing of the reusable first stage. Reviewing the video of their failed sea attempt, it's apparent that they were tantalizingly close to success there, and I can't help but wonder if they decided on a land attempt to mitigate environmental factors (ex. crosswinds) that may have been more prevalent at sea. It would be pretty amazing if
    • by Rei ( 128717 )

      Indeed... really they just need to land one successfully for now before going onto the next stage, which is working to prove that they can demonstrate and refine a process for refurbishment and return to flight in an affordable manner. One first stage returned intact gives them something to work with.

      • Quite. I imagine there will still be lots of refinement of the landing process for some time to come, but once they have landed one, then they can start figuring out what's necessary for refurbishment. I wonder if there will be a period of high-risk, cut-rate launches to test early refurbished rockets? I imagine there are a lot of projects out there where the cost of getting to orbit dwarfs the cost of the satellite itself, so that a high failure rate of early refurbished rockets would be an acceptable r

        • by Rei ( 128717 )

          Oh, sure, no question. Pretty much anything that's large and what you would call a "technology demostrator" (solar sail, experimental reentry system, large tether experiments, inflatables, anything of that nature) would go crazy for a cheap, even if high risk, rocket - when your spacecraft only costs a couple tens of thousands of dollars to build (or less) but launch costs are in the tens of millions, who cares if you lose the craft if it can save you a relevant chunk of the launch price? No question that

  • Is there a public viewing area? Is the space centre and museums still open on launch days?

    • Should be viewable from just about anyplace in Central Florida, east of Orlando... Coco Beach would be nice, but Daytona Beach would work on a clear day. Heck, hop on Turtle mound road at New Smyrna and drive as far south as you can and hit the beach there, or stand in a clearing in Titusville looking east. Thousands of places to see this.
    • by k6mfw ( 1182893 )
      Space View Park in Titusville has line-of-sight to Pad 39, I was there for the last Shuttle launch. I don't know specific of other pads at the cape. There is the Space Walk of Fame, small but very interesting museum, [] Though view will be miles away, and probably may not have 500,000 people including those that stop right in the middle of the freeways, maybe these SpaceX launches are like carnivals of enthusiasts like for Shuttle launches, []
  • by frank249 ( 100528 ) on Thursday December 10, 2015 @12:02PM (#51095031)

    SpaceX has a number of launches coming up according to Space Flight Now [] including:
    * 19 Dec - Falcon 9 rocket will launch 11 second-generation Orbcomm communications satellites.
    * Dec ? - Falcon 9 rocket will launch the SES 9 communications satellite.
    * Jan - Falcon 9 rocket will launch the 10th Dragon spacecraft on the eighth operational cargo delivery mission to the International Space Station.
    * Jan - Falcon 9 rocket will launch the Jason 3 ocean altimetry mission. Jason 3 will measure ocean surface topography to aid in ocean circulation and climate change research for NOAA, EUMETSAT, NASA and the French space agency, CNES.
    * There are others scheduled for early 2016

    • by Rei ( 128717 ) on Thursday December 10, 2015 @12:12PM (#51095069) Homepage

      Not to mention Falcon Heavy planned for around April to May of 2016 - which probably means "summer". I'm so looking forward to that one... 55 tonnes to LEO for somewhere around $100m... can you imagine what sort of probes we could launch with that kind of launch economy? Picture any probe we've launched thusfar and imagine what the designers could have achieved on that mission if they'd been given five times the mass budget.

  • They've proven they can put it down in a preselected area, the only hang-up appears to be the landing which judging from the last two attempts is due to not having a decent sized pad more than a control difficulty. Here's hoping that a landing on a much larger pad gives them the area they need for success.

  • by Alioth ( 221270 )

    As every KSP player knows, moar struts.

  • by frank249 ( 100528 ) on Thursday December 10, 2015 @01:24PM (#51095507)

    Article and pic here []. SpaceX is planning a main landing pad as well as four contingency landing pads at Launch Complex 13 at Cape Canaveral Air Force Station, according to a June 2014 environmental impact statement.

    The U.S. Air Force announced Feb. 10 that SpaceX has signed a five-year lease for Cape Canaveral’s Launch Complex 13, which was used to launch Atlas rockets and missiles between 1956 and 1978. In its new role, it will serve as a landing pad for Falcon 9 and Falcon Heavy booster cores launched from Florida, the Air Force said.
    “The contingency pads would only be utilized in order to enable the safe landing of a single vehicle should last-second navigation and landing diversion be required. There are no plans to utilize the contingency pads in order to enable landing multiple stages” at once, the assessment said.

    • Huh, curious end-quote positioning, if it had been

      >"There are no plans to utilize the contingency pads in order to enable landing multiple stages at once"
      or even "[at once]", I would have accepted that as obvious - multiple stages will by their nature land at very different times. The second stage is after all going all the way into orbit, performing its mission, and only then returning at its leisure, with the option to land pretty much anywhere since th entire planet is "downrange" once you're in orbi

      • by Rei ( 128717 )

        You forgot something: the Falcon Heavy, which begins launching next year, is basically two Falcon 9s hooked to an extra-long Falcon 9. Here's a video of the concept [] - basically, the side boosters simultaneously return and land, then the center booster returns and lands, while the third stage (which is the 2nd stage on the Falcon 9) isn't recovered. The design really stresses the SpaceX line of thinking - use as much duplication of parts as you can so that you can get economies of scale on production as we

        • Fair point, I did forget about that. That would likely call for three independent landing pads - you don't want the engine wash from a landing rocket to knock over one already on the ground, to say nothing of having shrapnel from a failed landing tearing through one that landed successfully. I.e. don't drop bombs on your own valuable assets.

          What problem do you see with the OTRAG? From the wikipedia article it sounds like an extremely viable concept. A bit lacking in technical elegance perhaps, and with

          • by Rei ( 128717 )

            OTRAG takes things too far. Yes, propellant and raw materials costs are only a small fraction of the total, but that doesn't mean that you can just toss ISP out the door. When you have to make a veritable mountain to launch a tiny payload you're giving yourself massively increased overhead costs - and unlike propellant costs, overhead is a big part of rocketry costs. You're also putting yourself in a far harder situation concerning environmental permiting, and the heavy (frequent) staging requirements and

"Even if you're on the right track, you'll get run over if you just sit there." -- Will Rogers