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Shit Elon Says - Transcript - Postlanding teleconference with Elon Musk

Transcript History  

I'm heading out to LZ-1 in a moment. But, if there any questions that weren't covered in the live webcast I'm happy to answer them. Everything we've seen thus far is that the mission appears to be perfect. The satellites were deployed right on target. The Falcon 9 booster came back and landed looks like almost dead center on the landing pad and then the upper stage did a coast and restarted to prove out the coasting ability. As far as we can see right now it worked, it was absolutely perfect. We could not have asked for a better mission or a better day. It was really amazing and spectacular and I think it means a lot for the future of launch. I'm happy to jump into questions.


If you can perfect this technology to the point where you can begin actually reusing boosters can you give us a sense of what that might mean for lowering launch costs?

Yeah, absolutely. The Falcon 9 rocket costs about $60 million to build. It's kind of like a big jet. But, the cost of the propellant, which is mostly oxygen and the gas, is only about $200,000. That means that the potential cost reduction over the long term is probably in excess of a factor of 100.


How confident were you leading up the launch today that you would be able to pull off the landing?

My personal probability, we looked into it last night before the flight, and I thought we had probably a 60% chance of success, maybe 70%. There's just so many things that have to go right and it's an incredibly complex set of maneuvers that the booster has to make. It's flying away from the pad in this case at 5000 km/h. In the upcoming flight it'll be going 8 or 9000 km/h, or roughly 5000 mph, in the wrong direction. So, it has to deploy the upper stage, do a u-turn, contain the propellant without centrifuging. The reason it has to be done with nitrogen attitude thrusters is because it's in a vacuum and has to be done quite rapidly. And then restart to boost back in a ballistic arc to Cape Canaveral, which was quite a scary maneuver. And then deploy the hypersonic grid fins and maneuver from hypersonic, through supersonic, to subsonic, and then finally to light the engine again for landing. I ran out onto the causeway to watch the landing and the sonic boom reached me about the same time as the rocket touched down, so I actually thought at first that it had exploded. But, it turned out to be just that the sonic boom almost exactly coincided with the touchdown point, the sound reached me several seconds later. I thought, well at least we got close, but then I went back into launch control and it was this amazing video of the rocket still actually standing there on the launch pad, or the landing pad I should say. I can't quite believe it.


What your plan is for this particular booster over the coming days and weeks and do you intend to fly it again?

The plan is to take the booster over to LC-39A, the Apollo 11 launch site that we are leasing from NASA here at the Cape and do a static fire on the launch pad there to confirm that all systems are good and that we're able to do a full-thrust hold-down firing of the rocket. And then I think we'll probably keep this one on the ground just because it's kind of unique, it's the first one we brought back. So I think we'll probably keep this one on the ground and just confirm through tests that it could fly again and then put it somewhere to display, because it's quite unique. I think we'll end up re-flying one of the subsequent boosters. We have quite a big flight manifest and should be doing well over a dozen flights next year. I think probably sometime next year we would aim to refly one the rocket boosters.


Can you try to put this event into historical context, where do you think it ranks?

I think this is quite significant. I can't say exactly where it would rank, but I do think it's a revolutionary moment. No one has ever brought an orbital-class booster back intact. This is something that was a useful mission, it delivered 11 satellites to orbit and then came back and landed. That's perhaps the thing that's really significant that we achieved recovery of the rocket in a mission that actually deployed 11 satellites. This is fundamental step change in technology compared to any other rocket that has ever flown. If you read the blog post that I wrote, I sort of penned it quite hastily just before the launch while we were going through the countdown, I think would give some good context. This is a boost stage capable of hurling 125 tons at over 5000 mph which is an incredibly amount of energy to transfer to a payload. There is really a world of difference compared to other rockets. It would be like having an aircraft that can be used many times when all the other aircraft in the world can be used once.


Can you touch on how challenging you think it'll be to get a reflight accomplished?

Straightforward, actually. Because we've done multiple full duration firings of the boost stage on the ground. We've fired the stage, including all of the engine restarts that had to occur while it was in space, and then coming back for landing, and during the engine acceptance testing, I think we've effectively fired the engines now, depending on which engine it is, between 10 and 15 times. Doing another batch like that would not be a problem, we see no degradation.


Are you talking about reflying the Merlin as well or the whole stage?

The whole stage. I think it's very important to refly the whole rocket. I think the aircraft or any other mode of transport analogy is appropriate here. You can imagine if a company was making aircraft that could be flown many times and another company was making aircraft that could be flown once, or even if most of the aircraft could be flown many times and some of it was single use, if someone kept the engines but threw away the airframe that really wouldn't count.


While the landing was certainly remarkable for everybody and you're excited for that. But, the launch itself must have brought some emotions to you considering what happened last time. Can you just talk about what you were going through and what point you thought you were back in business?

After liftoff, I ran outside the launch control center onto the causeway to watch the ascent and I was just wishing that it would make it to orbit. I think that would have been a good day frankly if it would just been that. Then I was in touch with the rest of the crew in launch control and they were giving me updates on the flight. And then I watched the booster come back in, light its engine, and land. It really felt like it was almost on top of us even though it was 3 or 4 miles away. As I mentioned earlier, the sonic boom, sound only travels at 1000 km/h, the sonic boom reached me just as the rocket touched down, so I thought it had exploded. And then I learned from launch control that it was in fact okay. That's pretty much what happened.


How do you expand upon having a rocket that you can reuse, what do you amortize the number of flights, at some point do you have an engine that's worth the cost of launching at cost for somebody? Have you planned that out yet or waiting to see how many of these things you get back?

I think we're going to get quite a few rockets back, so I imagine we're going to have a whole fleet of booster rockets accumulating quite rapidly because we're building them right now at about one every three weeks. Even if the success rate is only two thirds, but I think over time it'll be over 99%, it's going to asymptotically approach 100% over time and then we'll figure out how to make the reuse as easy as possible where no work is required between reuse apart from refilling the propellant tanks. It'll take us a few years to iron all that out and make sure it all works well. I think it bodes very well for the future and I think it's a critical step along the way towards being able to establish a city on Mars. It's quite vital to that goal and reusability of an orbital-class rocket is surely fundamental to that goal. Without it, it would be unaffordable. It would be a difference between something costing less than 1% and something costing 100%. It's all the difference in the world. Absolutely fundamental. I think it really dramatically improves my confidence that colonizing Mars is possible. That's all it's about.


I wanted to know if you could talk a little bit about what you were thinking tonight, you had the world watching and you stuck this landing. I was wondering the kind of pressure you felt before it came down and then what it felt like when you saw the reaction online and at your company HQ?

I haven't had much of a chance to look at things online. Certainly, a lot of things happened today at Spacex, as the video showed. It's been thirteen years since SpaceX started and many close calls. We had some good results with the rocket test rig, the Grasshopper, it stuck the landings there. We didn't make a big deal of it, we did land the Falcon 9 in the water twice, and those were high velocity missions. I think in one case exceeding 300 gigajoules kinetic energy transfer and an altitude of 200 km. We did do that twice, but didn't show a press release of it, but the videos are on YouTube, we just didn't make a big deal of it. I wasn't 100% confident that this would succeed, but I'm really glad that it did.


My question deals with the next booster, the Falcon Heavy. How much of this successful landing can be applied or scaled up that heavy rocket and does it boost your confidence for that booster too?

The Falcon Heavy essentially consists of the Falcon 9 with two modified boost stages attached as strap on boosters. That would be quite an exciting aerial ballet with the two side boosters dropping off and doing a symmetric pirouette back to the launch site. We'd need to have another landing spot for the two boosters and then a third one for the center core. Although I think most of the Falcon Heavy missions will see the center core land on a ship most likely. It's really going ridiculously fast. The transfer energy of Falcon Heavy will more than double that of Falcon 9. The maximum transfer energy is approaching a terajoule.

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