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SpaceX's First Official Cargo Resupply Mission to the ISS - Launch Webcast (livestream.com)
184 points by Reltair on Oct 7, 2012 | hide | past | favorite | 95 comments

One of the best things to happen during this launch is that an engine exploded. You can see engine 1 eat itself at 1:31 in this video:


[Edit: First the video was public, then it was made private, now it seems to be "unlisted" but viewable. So no guarantee that it'll still be there in another minute...]

Why is this a good thing? Because it proves a point: the rocket automatically adjusted its trajectory, and continued on its course as if nothing had happened.

The Falcon 9 is the first American rocket since the Saturn 5 with an engine-out capability. Its multiple symmetrically-arrayed engines allow for it to compensate for a sudden loss of thrust from one side: the other side reduces thrust as well to stay balanced, and everything else just burns a little bit longer. That was the theory, anyways. Today they put it into practice.

For any other rocket that you've seen launched in the last 35 years, that would have ended the mission catastrophically -- but the Falcon shrugged it off like nothing had happened. They always said they could do that, and now they've done it. Congratulations, SpaceX! Creating a fault-tolerant rocket is much better than creating a faultless one (since that's impossible).

[Edit]: In the absence of the video, the engine anomaly is being widely reported on Twitter: https://twitter.com/spaceteam/status/255128401927610368 https://twitter.com/visionik/status/255128010653593600

Here's a high quality 1080P slow-mo clip of the explosion. You can clearly see huge pieces of debris falling off for several seconds afterwards.


While I'm glad that everything worked out well for SpaceX, I would not be so quick to consider it a smashing success. Correcting for an ineffective engine is a fantastic feat of engineering, but consider that the engine obliterated itself due to some other unknown flaw. The bigger issue with blowouts like tonights is that the violent nature of the event can damage surrounding engines, or the failure could be caused from a common system. SpaceX was lucky that it was a corner engine that exploded, as it was least-likely to damage any of the other engines. Excellent redundancy engineering allowed them to continue the climb to orbit, but only after they got lucky.

Then again, it is unfair of me to make relatively uninformed declaratives about tonight's launch. The engine blowout could have been cause by an incredibly unlucky set of circumstances, and the engineers at SpaceX could have built a vehicle that survived a catastrophic failure that would have doomed any other craft to date.

Given what I've seen from SpaceX, I am positive that they will get to the bottom of the incident and have it corrected before their next launch.

Each engine is surrounded by a kevlar blast shield, in anticipation of exactly this kind of scenario. While there have been previous rockets with an engine-out capability (the Saturn 5 first stage demonstrated this, for example), I believe this is the first rocket explicitly designed to survive an explosive engine failure.

No doubt they should do an investigation to see if the cause of failure can be determined and corrected. It's possible that the fault may no longer be an issue; this was flying the soon-to-be-retired Merlin C engines, and the design or manufacturing flaw may not have carried over to the Merlin D engines. But what they shouldn't do is spend billions trying to make the rocket perfect, which has been the traditional approach. A few million + redundancy is much better.

A very important distinction is that liquid rocket engines should be shut down when problems are detected, and an explosion should not occur.

This has been done many times in history, in Saturn V and Space Shuttle for example.

But in this case, since the engines are so small, it seems the explosion tactic paid off very well.

Hopefully they can test Merlin-1D adequately. If you aim for reusability, your reliability must go up considerably. If you plan to fly something for 100 times, you probably can not tolerate 98% per-flight reliability. A lot depends on assumptions of course.

All very true. Although as I note in a thread below, I'm starting to wonder whether this was truly an explosion (ie of the combustion chamber and everything), or simply a nozzle collapse following a commanded shutdown of the engine. The latter would be relatively benign, aside from some aerodynamic effects which the flight dynamics software obviously handled without trouble.

And you're right -- for reusability, they do need to get their per-engine reliability above 98%. That would produce a mission reliability of 97.1% (assuming that 2 engines out causes a loss of vehicle, which I understand is only the case during the earlier phases of flight). At 99% engine reliability, you get 99.3% per-flight reliability -- which strikes me as the point where reusability starts to become very sensible. I have considerable confidence that SpaceX will be able to do this.

Well spotted! I missed that during the live webcast, there was absolutely no mention of it. Some people at SpaceX should be pretty hard to play poker against, there was 0 indication that they were aware of any issues.

Bringing a RAID approach to engine configurations seems to have paid off quite handsomely.

There was a point where they said something along the lines of "the rocket is on an anomalous trajectory", and I was wondering what they hell they meant by that, since they didn't follow up on it.

Way to go SpaceX! I'm just as thrilled by the fault tolerant system working as designed as I am for the launch itself. SpaceX is proving again and again just how well thought out and robust their system is.

Wow, that's a great catch - I did notice the turbulence from the explosion in the webcast and thought "whoah, that didn't look like it was planned", but everything went so smoothly afterwards that I just wrote it off as the supersonic shockwave or something like that.

Well, to be fair, I may have jumped to conclusions by calling it an "explosion". Something disassembled itself for sure, but it may have just been the bell nozzle rather than the whole engine (combustion chamber, turbopump, etc.).

SpaceX is calling it an "unplanned shutdown", but it's unclear at what point the shutdown was commanded. It's possible that some off-nominal parameter triggered an engine shutdown, at which point the sudden vacuum inside the engine bell would have caused the nozzle to collapse. (Note that this happened at Max-Q, the moment of maximum aerodynamic pressure, so the outside force on the nozzle would have been significant). This would have had some impact on the aerodynamics of the vehicle (with the flight dynamics software compensating perfectly), but it wouldn't really have been a threat to the other engines, and is not too dissimilar from some unplanned shutdowns which the Saturn V experienced. It wouldn't really count as an "explosion". It might just be a (relatively benign) software bug which triggered the shutdown.

On the other hand, the engine might have disassembled itself first, followed by the shutdown order to keep it from dumping uncombusted propellant. This would be an actual explosion of the engine -- contained by the kevlar shielding to keep it from damaging the surrounding engines. If this is the case, then it's a huge validation of SpaceX's RAID-like design philosophy, since I don't believe that any launch vehicle has ever survived such an explosion, much less completed its mission to perfection.

New video (not private) with engine blast around minute 5:21


I checked out the video you linked. It's now all of a sudden marked Private for some reason... Is there any corroboration from SpaceX that there was indeed an engine failure? It looked to me like it could have been ice breaking off near max Q or some kind of shockwave interacting with the exhaust plume. I'm not questioning your observation but it didn't look definitive to me. I agree that having redundancy is good though.

Yes, the loss of engine 1 was apparently confirmed in a press conference.


Nice. Thanks for pointing this out.

The video is now private, does anyone have a mirror?

'This video is private'

I have a favour to ask of HN.

I'm responsible for webcasting Copenhagen Suborbitals launches, and we're having a lot of great discussions about what works and what doesn't in a live webcast of a launch. We obviously want our webcasts to be as interesting as possible, and so I'd like to ask you a question:

What do you think could be done better in this Space X webcast? Is there something you're missing? Something you think would be cool? Something that's bothering you? Are the speakers good? Why?

I'm sure we can learn a lot by asking potential viewers what they think, and implement it for next summers launches.

And good luck to SpaceX!

I'd like it to be richer in information, even if I won't understand all of it. I'd like to see diagrams of the engine, description of how it works, discussion of pros/cons of various technologies, how this one is different, etc, etc.

For example, they mentioned they don't want the rocket to fly through clouds because of water vapor. Why is that? How does it interfere with the rocket? What can it cause? How confidently can we measure water vapor in atmosphere?

Simply, much more technical information and more educational.

Something I would like to suggest, now that we're at T+00:06:40 it would be cool to see more than just the second stage engine doing its thing. The live feed from the craft is always interesting, but now that the ground cameras aren't able to provide "cool" tracking shots of the vehicle, I would like to see telemetry data. Current speed, distance from launch, and maybe a map with the position superimposed would be interesting to me. Basically something to give me a broader overview of what was/is happening. Thanks for the awesome live feed!

And Dragon is in orbit! Congratulations to the SpaceX team!

one vote from me! I kept listening and hearing "blah blah km", but it doesn't mean anything to me so I had to look up what else is at 200kms in altitude.

Maybe an updating checklist you tick off, as the launch progresses. Normally, the steps to amateurs just seem to be (1) Launch. (2) Don't crash.

I'm sure there are some steps before, between, and after those two. :)

It would also make it more exciting to watch, since it makes the sense of progression and success more tangible.

That's an excellent idea!

Thats a fantastic idea.

So far so good, the pre-launch show is interesting, full of interesting content both live (Q&A) and pre-recorded videos.

The speakers reading from a prompter is a bit too obvious at times but this is a minor annoyance. It's awesome that they are actual engineers/managers involved with SpaceX's day-to-day operations.

(It might make sense to setup an off-site poll for this, I'm not sure Hacker News' commenting system will scale well for this kind of feedback.)

Yep. Real engineers FTW!

You need to find engineers who understand the stuff AND can also speak clearly. Or can train to improve in either.

I realize many engineers are not good at speaking to general audiences since they might use jargon or are really slow, stutter etc.. Probably they can improve a lot if you pay attention to it and consider it important and devote the necessary resources like time and money.

I'll take an opportunity to ask you a question.

I saw the news the other day that you guys had written a video mixer for Linux, with integrated Chyrons, transitions, and all that. That's great work, but I do have a question about the motivation behind it.

As a former television technical director, I was curious what made you choose to write a custom software video mixer. The alternative, of course, would be picking up a cheap digital mixer, like a Grass Valley, and encoding its program output instead. Was the impetus financial in nature? Technical, since making a video mixer train work is a little challenging unless you have experience (reference signals, CCU if you have fancy-enough cameras, and so on)? Are you mixing audio in your software suite as well, or do you have an external mixer? (The rationale for each is the same, IMO.)

I'm just curious. Not saying the work isn't valued, just steaming ahead on writing a custom software mixer is an interesting decision. Production houses usually have old digital mixers in storage and might be willing to donate to your effort, too.

It's a very good question!

Launches are done in the Baltic Sea, 30-40 km. east of the Danish island Bornholm. In order to stream live we managed to get a wi-fi connection going from Bornholm to the mission control ship 40 kilometers away, but we couldn't reliably get enough bandwidth to stream all our camera positions to Bornholm. Furthermore internet connection on Bornholm is not very good. The result being that we needed to do the videomixing at sea. Only problem was that the broadcast studio, and thus the people that need to do the vdeomixing, were placed in Copenhagen. The result being this videomixer where we can send two streams from the launch site at sea: the livefeed and a mosaiq of available camera positions. The studio in Copenhagen can then remotely mix the livefeed based on the mosaiq using a webbased interface, or a commandline.

Ah, that makes sense, so you're sending a program and sorta-preview from this custom tool to a fuller production studio and it's remote-driven. That makes more sense.

Right on, thanks for answering.

With the studio consisting of our speaker, Peter who wrote the snowmix mixer, me and a few laptops in a backroom in the local planetarium. So a studio is probably overstating it. But hey, that's what you can get with a budget of 0.



I would love to see a channel or webapp that had the real-time telemetry feeds. As techy as possible.

That's actually one of the things we're working on. We're hoping to have a fighterjet-like heads up display showing altitude, roll, pitch, etc. that will be overlayed on the stream.

You may consider showing the rocket in relation to the Earth. I tuned in at T+7 and just saw an engine burning, now at T+10 the engine cut off and the thing is in orbit. I have no idea where the rocket is at this point. Would a live Google Earth feed be a possibility?

Very cool stuff.

I think even a 2d map with a dot for the object would be serviceable and neat in cases like this. Maybe draw the flight path in a swath that changes color over altitude.

In example, think how meteorologists on TV use color on a map to show the how much rain has fallen.

dark green -> green -> dark yellow -> yellow -> orange -> red -> blinking purple

Just use a gradient with colors that won't interfere with whatever map you're using. Maybe just "yellow -> orange -> red" as it progresses to its target. Then once it hits it, switch to white, and continue to chart the movement as long as you broadcast.

The launch coverage was too clinical. 1,800 employees behind the company and they must be absolutely ecstatic right now. There were very brief audio snippets where you could hear cheering, but it would have been great to have gotten to feel what it's like to be there inside Launch Control. NASA Curiosity did a much better job of this, with applause, cheering, hugs, and high fives.

Congratulations to the whole team at SpaceX!

I _LOVED_ the fact that they had an engineer co-hosting the webcast. He wasn't the typical pretty-boy spewing stuff from a teleprompter that he didn't understand, and his post-launch elation said it all.

Go for quality information, even if it's a bit rough around the edges from a BS marketing standpoint.

Get a REAL rocket scientist spreading the word.

Both of the hosts were engineers, actually.

The likely difference is probably not enthusiasm, but the fact that the Curiosity folks were just along for the ride. Everything happening had already happened minutes ago.

I love being able to hear their comm checks. It really makes you feel like you are actually there.

"Vehicle is supersonic."

gives me the shivers every time

Subtitles - Not all the world is sleeping, now we are currently sitting here in an office. Many of us have the webcast up on their screens, but we either don't have headphones or don't have the sound on.

A timeline of what is supposed to happen - Since we had no sound we were left wondering what was happening, and when the next event should be. It would be nice to have something like:

   T-30 - XXX
   T-5 - YYY
   T-0 - Launch
   T+2 - ZZZ

The engineer host sounds like a goofball. When he tries to add his personality it sounds really artificial and forced.

He is very goofy but exactly what I would expect from a rocket engineer doing tv hosting. Quirky but awesome! Doesn't sound artificial to me at all, but I'll agree he doesn't sound very comfortable doing it yet.

The male engineer is a little nerdy, but it works for me. The female engineer is more polished, but still slightly nerdy in an appealing way.

Serious question -- in the past, when NASA wanted to launch a rocket, they would contract with a commercial company such as Lockheed, Douglass, or some similar. Now they contract with companies such as SpaceX. Why is this considered a commercial / private space launch, but the others in the past were considered government funded? NASA is paying for the launches in either case. Or is it the level of involvement and control that NASA has in this case?

Hold on, it's more complicated than that, but we'll get back to that in a second.

NASA contracted to launch the Curiosity rover on the Atlas V rocket, for example, so how is this different? Well, the Atlas V wasn't developed commercially, it was developed as part of the EELV program. This was a USAF program which sought to develop launch vehicles to carry military payloads into orbit in the future. Boeing and Lockheed Martin developed those launch vehicles (which became the Delta IV and Atlas V) but government had a lot of say on the design of the vehicles and ultimately paid for most of the development cost of the vehicles. This is different from SpaceX's example where they developed their own launcher from scratch to their own design, specs, and manufacturing and management processes, etc.

Also, if you look at other NASA launches in recent history the contrast is even stronger. NASA drove and funded development of the Delta II, the Shuttle, the Saturn V, etc, etc.

Additionally, operations for the spacecraft component, the Dragon, is being handled by SpaceX themselves and not by NASA, which is a new thing, especially in the realm of manned spaceflight.

NASA isn't just buying launches, nor are they just buying Dragon spacecraft and launches, they are buying cargo delivered to ISS.

I think that last sentence in your comment summarizes it best. They are now, basically, just paying for "shipping" their cargo into space. That is awesome.

So it's basically like the difference between a company hiring contractors to develop a custom accounting system, vs. going out and buying a copy of Quickbooks. Makes sense now.

My understanding (I may be mistaken) is that the level of involvement and control in the two cases is different. SpaceX runs their own mission control for their launches, and the amount of NASA involvement in creation of the vehicles is different (from what I understand). As an example, the Space Shuttle was built by Boeing, but was operated by NASA. von Braun's crowning achievement at NASA, the Saturn V rocket (about as pure a "NASA" rocket as you normally think of) was built by Douglas/Boeing/etc.

Beyond that, the interesting bit I think is the difference in the contracts that SpaceX has, and the contracts that have traditionally been given to space contractors. Traditionally overruns would be covered by government funding, but in the case of SpaceX they eat their own overruns. The result of this seemingly minor change in funding is that they are far less "quasi-government" than space contractors traditionally have been.

the pricing is a big diff. the big prime contractors tend to cost more per payload mass than SpaceX. plus the primes do pricing based on "cost plus" which means a general incentive to increase costs in order to increase profits. SpaceX is doing firm fixed price quotes, and builds their profit margin into that (at least in long run, after R&D costs recovered), and eats risk, as you mentioned.

Also, and this is big, frankly SpaceX is operated in a much more nimble and entrepreneurial fashion. The primes, while having lots of very smart and well-meaning people working for them, have BDC-itis. Musk wants to dramatically improve the world and the species, and put a colony on Mars. The leadership of the primes seem to just want to make money. Musk/SpaceX is more exciting and compelling for a lot of folks, plus they're more likely to lead to spin-off missions down the road.

Difference is people who managed the program and who paid for it.

Early rocket programs were military programs, rockets make excellent weapons, they can reach around the world and touch someone in less than 90 minutes. The military paid for, and managed, programs for putting payloads into orbit. Of course the military doesn't have a rocket factory, so it hires contractors to build rockets to its specifications, and to research questions the military wants answers too, Etc. NASA worked with the same contractors as part of the civilian space program to give scientists access to space.

In the military programs, function was important, cost was not. That is because the military has "cost plus" contracting, they say "we need a rocket that does X" and the contractor builds it and charges the cost of building it plus the agreed upon 'profit' and the military pays it. There is no incentive to be economical and no incentive to change.

SpaceX on the other hand invested its own money in building its rockets (that's the 'private' part) and they are selling services on these rockets at a price that makes them a profit on their investment (that is the 'commercial' part). They have been re-using research done by NASA and the defense contractors in their work so they have an advantage over earlier efforts in terms of costs. That said, by approaching it as a business rather than a government contract they have removed a huge amount of cost out of the process.

Because of the process, SpaceX isn't necessarily constrained by the restrictions a nation-state might put on them (although in reality if they tried to sell launch services to say Iran the US would prevent that) They also have the right to re-use their technology for their own enterprise so if Bigelowe Aerospace needs someone to launch their space hotels, SpaceX can offer that service without either Bigelow or SpaceX needing 'permission' from the military.

The amazing bit here is that nation-state space programs were possible because nobody expected to 'make' money, they just took tax payer money and burned it at a high rate :-). In this case SpaceX is looking to recoup their development costs and then some. Not being under the whims of a nation-state budgeting authority (like the US Congress) allows them to make progress quickly.

It's a lot like the difference between contracting to have a piece of software built, and buying a copy of a piece of software that's already built. You get a lot of control with the former, but also a lot of cost, and the result often doesn't generalize well.

Previous systems had heavy input for specs and design from NASA. With this, NASA basically says, "X pounds for Y dollars to ISS" and SpaceX is figuring out all the details.

I think the main difference is that the launch is made using a commercial launch vehicle/capsule. If you had the money, you could hand Space X a ball of metal and a pile of cash and they will put it in orbit for you. Just because the government is the first paying customer doesn't mean it isn't commercial.

One small correction which I think makes the difference even clearer: the US government was not the first paying customer. SpaceX has already delivered several satellites into orbit for other non-US governments and corporations.

Says Wikipedia, and my recollection, the first two flights of Falcon 1 were purchased by the DoD, i.e. the US government, so that's not correct.


I stand corrected. Sort of since the DoD wasn't really a customer in those cases. And the reference listed doesn't specify that the first flight was paid for by the DoD.

Difference is between cost plus custom government contracts and fixed bid ones.

Think of it like the difference between the cost of developing a new product such as an iPhone before scaling it out (cost plus) and the cost of the delivery of the final product (a final complete iPhone from the city store).

Good question. The main difference is the assumption of risk. Even though previous launches were often operated by private companies (and of course the launchers were built by the private sector) they did so on cost-plus contracts. SpaceX will be paid a fixed fee for delivering cargo.

In the past, Lockheed and Douglass had contracts to build the launch vehicles and support systems, which then became property of and were maintained by NASA. SpaceX has a contract to deliver cargo, meaning that the launch system and control is entirely theirs and NASA cargo is merely hitching a ride on it. Exciting times, my friend.

I watched this launch live with my children under the giant maple tree in front of our library. I was surprised when they called me out on my predictions of the timing for first and second stage separation. They are learning from this. I love that my daughter, who wants to be a scientist, could watch Gwynne Shotwell comment on the launch afterward and know that she is a world-class engineering executive. On the way home, my son spotted a home with a new rack of solar panels on the roof and a fresh Solar City sign planted in the yard. And my kids are dreaming of getting Teslas for their first cars. What an amazing set of accomplishments set into motion by one great founder.

Yay! SpaceX scores again, congratulations to Elon Musk and the whole team there.

Every time I watch one of these I feel that I'm watching history being made. And I wished I could stop holding my breath through the last 20 seconds or so. I also feel like I'm 6 years old again.

Another awesome SpaceX launch, very nice. Instead of hats and t-shirts from the SpaceX store I'd love to see them offer that 'launch workstation config' (three monitors, wrap around table) I'd get one of those for my lab in a heartbeat.

I just think it's pretty damn cool that space launches have gone from the old 50's mission control room to something that looks like a very boring LAN party in a student lecture hall.

Wow, they're going to land the ignition rockets in future launches! That's great and sounds like it would be cheaper than the NASA space shuttle. Can't even begin to imagine the amazing feedback control that'll go on in that thing.

While that sounds great, i wonder what the advantage to that is over using parachutes and making a water landing like the Shuttle Solid Rocket Boosters did.

This question always comes up.

It's about turnaround time and precision. Parachutes are messy. They use pyrotechnics to deploy, they have to be packed very carefully and precisely, etc. They also don't lend themselves to precision landings well. They're fine for landing in an enormous landing zone in the ocean or in some unpopulated, featureless desert, but otherwise they're not so good for targeted landings.

Now, compare this to propulsive landings. You "waste" a lot more fuel and cut into the payload of your vehicle but on the other hand you get to streamline the turnaround process to just a matter of refueling and inspection, which you would do regardless of the landing mode. More so, by landing the vehicle in a designated spot you dramatically lower the cost and time necessary to put the vehicle back into service. You don't have to drive out to the desert and retrieve the vehicle (which could take a day at least) you just pick the thing up with a crane and you move it a few hundred meters to the hangar / processing facility.

thats what i figured. Although to me it seems like a lot of moving parts, and big hit to fuel and payload. I wonder if development focused on optimizing it as a one use booster and driving down the cost of each booster might be more efficient in the long run.

That's a very worthwhile point but there are a few major reasons why it's a more problematic strategy.

First, reliability. When you engineer a vehicle as large and as complex as an orbital launcher which only operates once in its entire lifetime you typically need to over-engineer a lot of key parts of the thing in order to ensure a high level of overall reliability. This runs counter to the sorts of optimizations necessary to bring production costs down by orders of magnitude. More so, when a full up test inevitably results in the destruction of the vehicle (because it is expendable) and tests cost as much as a launch (tens of millions of dollars) it makes it very, very difficult to evolve the design of the vehicle extensively.

That leads to a catch-22, you have to run a lot of launches to make the vehicle design significantly cheaper to manufacture. Buuuut, now you've vastly increased the development cost of the vehicle so you've erased all of the cost gains you've made.

But, if you design for reusability then you can actually increase reliability because the cost of the vehicle is amortized over multiple flights, so you can have a more expensive vehicle.

Also, while a lot of aerospace components (like fuel tanks, electronics, etc.) can be mass produced with the right design, this is a lot more difficult with rocket engines which have a very high number of precision machined parts made out of special alloys. This makes the engines the long-pole in the costs of a rocket, and it's very difficult to reduce those costs. Right now SpaceX is already the world's largest manufacturer of high-power rocket engines, so if there was a way to cut costs on them they would already be on top of them.

Now, back to reusability. Another thing that you get from reusability is that testing can be much cheaper, since you can make incremental changes to a vehicle design and then re-test it.

With reusability you have the best of all 3 worlds. You have reliability, you have low per-flight costs, and you have an enhanced ability to prove out potential vehicle redesigns economically.

Now, if the size of the launch market were much larger and reusability were more difficult then the equation could change, because it might be easier to recoup expensive cost-saving efforts over a shorter period of time.

At least for the first decade or two (maybe still - I don't know) the shuttle SRBs were only recovered for political reasons - the system was supposed to be reusable and they didn't want to be accused of building an expensive disposable rocket.

By the time the boosters were recovered disassembled, had every inch checked for damage (visible and xray), and rebuilt, the cost was more than if they'd just left off the parachutes and built a new pair for every launch.

In theory if you landed the first stage of a liquid fueled rocket back near the launch site you could just gas it up and launch again, since the stresses are so much lower. I doubt that's what will happen, though - they'll give it a pretty thorough (and expensive) going over the way NASA did with the SSME.

There are two ways this could make sense from a cost perspective. One is after a confidence-building period they just do quick inspections and live with a slightly higher failure rate on subsequent launches. This would mean the second and subsequent missions are unmanned only, and it would have to bring the cost down so much that satellite makers could afford the risk.

The second is they just do relatively quick and cheap inspections and the increased failure rate is so small it's balanced out by the decrease in failures due to manufacturing error. This is really the holy grail of the rocket business, since it means you start to operate on the same economics the airlines do, where fuel is the cost driver. In rocket launches fuel typically comes to about 2% of the cost.

Putting a kg into LEO takes about the same amount of energy as flying it from LA to Sydney on a 747. The reason sending that kg to Sydney is so much cheaper is they turn the plane around and fly somewhere else instead of throwing it away.

It's basically a savings in recovery and turnaround time & expense. Sea recovery is logistically costly and difficult, plus the vehicle must be completely rebuilt and refurbished once it's back in the hanger. A saltwater bath and the stresses of a water touchdown are not easy on equipment.

While a controlled, retrorocket touchdown is obviously s huge engineering challenge and greatly complexifies the vehicle and increases its launch weight, the possible cost savings apparently make it a desirable goal.

Also, I believe SpaceX hopes to perfect the technology as part of their strategy to be make their tickets to Mars "round trip" :)

Turn around time. You can turn around a self-landing ignition stage much faster than something you have to turn around after a water landing.

Well, not for a couple years, right? Anyone know when the first powered return-to-lunchpad can realistically be expected?

Not yet scheduled. They now have a test rig ("Grasshopper") with one engine, first-stage tanks, and extremely heavy, fixed legs, which they'll presumably be using to check out flight control algorithms for return and landing; it just took its first, very brief hop off the ground. It's not likely that they'd schedule any launches with a reusable first stage until they had a pretty extensive series of suborbital tests with rigs like this.

Yeah - definitely a couple years. They're in early testing right now. It was just "proved" through computer simulations a few months ago.

The condensed gas that we see shooting off perpendicular to the side of the rocket, in 2 locations near the top - what is that?

I recall them saying it was liquid oxygen venting.

Since it's a kerosene-fueled rocket motor (RP-1), there's only one kind of cryogenic tank per stage, and that's the LO2 tanks. So you're correct, that's the only possibility.

We have liftoff and in orbit... Nice! I got nervous. Best tech news since Curiousity =)

Is this supposed to work on iPad? It taunts me with the promise of a QuickTime-looking play button, which unfortunately doesn't actually do anything when I press it.

There's a Livestream app you can get which I assume would let you watch this.


Odd. It works on my iPhone. May want to try it again.

Try the NASA TV feed.

it was so unbelievably beautiful, how the rain caught the rocket's glow. what a beautiful way to leave the earth

Launch webcast begins in T-1 hour!

This is absolutely fascinating, like being an astronaut without leaving my desk!

Congrats to SpaceX on a successful launch and a great webcast!

anyone know what that background tune is?

No, but it is SUPER annoying after the 25th or so repetition.

I'd mute it except that I want to keep the thing open in another browser tab so I can switch to it when the show starts.

Lesson learned: don't use repetitive audio crap while waiting for a web cast to start. Just have silence, then start talking when it's actually starting.

On the other hand, having no sound until it starts means people might get startled when you actually start (or have them not realize their speakers are off).

A very short voice announcement every minute or so would be okay.

And/or just 1 iteration of the music.

I just wish it'd stop repeating.

Congratulations, exciting

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