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SpaceX SES-9 Mission Live Webcast (spacex.com)
152 points by nerdy on Mar 4, 2016 | hide | past | web | favorite | 90 comments

Elon confirms 1st stage did not get a good landing


Edit - text of tweet: "Rocket landed hard on the droneship. Didn't expect this one to work (v hot reentry), but next flight has a good chance."

Very impressive nonetheless. I am wondering if they had a loss of the drone ship?

It's unlikely the drone ship would be lost. The rocket is coming in nearly empty. The explosions we've seen in the past are really just the remnants of fuel briefly burning, it's not all that powerful. The rocket itself is light compared to the ship. It's a little bit like someone throwing a soda can at your head. It'll hurt, but it won't break your skull. Some of the support equipment on the deck might take damage (there are fun pictures of the ship after previous attempts with various items dented and scorched) but the ship itself should be fine.

> The explosions we've seen in the past are really just the remnants of fuel briefly burning

And rapid de-pressurisation.

Ah, OK. For some reason I had the mental image of a bunch of inexpensive ships which would surely sink if they got hit at high velocity. It's pretty incredible, given how large the rockets are, that the ship dwarfs them, but recalling earlier landing videos you are correct.

Just to put some numbers on it, this barge is the MARMAC 304, modified by SpaceX. According to this page:


That ship has a cargo capacity of over 13,000 tons. I believe an empty Falcon 9 first stage is around 20 tons. Totally different scales.

I read that entire barge blog. Its interesting.

Do they 'refurbish' the barge ? It's the .. 4th time ?

> It's a little bit like someone throwing a soda can at your head.

A mostly empty can. And it should be moving slowly when it hits.

Hah, no, the drone ship will be ok, it's pretty strong.

Rainbow-bars [NO SIGNAL] right when stage 1 was landing on the barge...

So suspenseful!

The last frame before video cut out http://i.imgur.com/3HCnn7c.png

Edit - looks like stage 1 did not survive landing (this time).


The Drone Ship says, "Sorry guys :(" https://twitter.com/TheDroneShip/status/705907706209693696

While I'm sure there are a number of people who are really interested in the SES-9 success, I was really hoping to see a water landing. I continue to be amazed at how difficult it appears to be to get a reliable signal from an unmanned boat out in the Atlantic back to land.

It looks like getting a signal in normal circumstances is doable, but problems occur when a 200ft rocket shows up wanting to make friends.

Lots of motion in the frame -> high bandwidth requirements.

That might cause the video to go funky, but it shouldn't cut the feed. My guess is that the satellite dish or other communications hardware gets upset when the first stage effectively takes a flamethrower to it.

Seems a likely explanation. Its the engineer in my that goes wild here though, I think "why not have the uplink on a smaller flotation unit being held in place by a sea anchor? Or given the amount of time needed to monitor the return is relatively short (you know to the minute when it "should" touch down) could you launch the uplink on a hex a copter so that it could stand off from the barge, free of vibrations while the rocket landed? How about a 2.4Ghz cross link to an independent platform with its own uplink? How about using a towed fiber optic cable to a remote relay station away from the barge? Etc. I totally understand that this is a small (and in the larger picture unimportant) part of the mission, but the problem calls to me :-)

The issue is vibration which throws the uplink out of alignment with the receiver.

Or just shakes it a lot.

You can stick a NAS into a bouy, connect it to the drone ship with a long-ass network cable and have a petabyte of storage over a 1Gbps link that will survive anything that may happen to the drone ship.

A petabyte over a 1Gbps link would take ~94 days and is probably far more than what is necessary, so I'm not sure why that's included here.

The ship itself is pretty strong.

A new market for hug of death.

Yeah, at least this time we expected that to happen. (SpaceX webcast guy indicated the rocket shakes the uplink dish so hard on approach it's likely to lose signal every time).

I do wonder why they don't have a separate small barge with a couple fiber runs between them, to do the comms (e.g. host the dish(es)). I guess it just isn't that important.

That was asked on the spacex sub-reddit. The response was something like "you underestimate the power of a Merlin" which I took to mean that a reasonable distance to avoid the effects is too far to reasonably run ship-to-ship cabling.

That's totally reasonable, too. I had assumed that the wash from the rocket would be largely straight down, but that's probably way wrong.

It is probably pretty much straight down...until it impacts the flat surface of the ship.

Fiber optic cable is relatively light weight and strong for the bandwidth it supplies. This seems like a cop-out.

I'm sorry, but is it possible that the literal rocket scientists have given it more thought than you've given it credit for?

I've only been posting here for a bit over a year. Has HN always had an issue with these sorts of pragmatic speech mis-queues where one posits that the experts are not aware of some painfully obvious solution? I find it to be condescending, but I'm not sure that such commenters realize it, and so I struggle with pointing it out - in case they didn't honestly realize the issue - or keeping my mouth shut, thereby avoiding potential conflict with someone who either can't be swayed or may actually be smarter than the group whose collective knowledge is being challenged.

EDIT: I asked a legitimate question. Down votes don't teach people who want to learn, people.

Sorry, I don't know who gave you the downvote - it wasn't me.

It does seem to me that the rocket scientists would have had their hands full with all the other issues around the launch and recovery. My guess is that the live feed isn't a priority for them, knowing that they can get what they need after the fact.

Probably the naval architects who designed the barge are well-aware of underway replenishment procedures and know perfectly well how to connect two vessels underway. And probably asked the rocket scientists about some of these issues before drawing up the barge. Because, selling an unrep solution is going to cover a really nice year end bonus. The raw steel would cost more than half your lifetime earnings.

> Has HN always had an issue with these sorts of pragmatic speech mis-queues where one posits that the experts are not aware of some painfully obvious solution?


Mod dang has spoken about it a few times. Here's one example, but there are others: https://news.ycombinator.com/item?id=8769453

Note the way he talks about it is less harsh than the way you talked about it, which may explain some of the downvotes.

>EDIT: I asked a legitimate question. Down votes don't teach people who want to learn, people.

You demanded answers. There's a big difference.

Help me out here: where is my demand?


From your profile:

>Hi, I'm Bucky. I'm sorry if I've come off as a jerk, communication on the internet is really tough.

It sure is, so thanks in advanced for your helpful response.

You are arguing from authority, which is a fallacy. It does not matter who thinks something is obvious nor what labeled group you ascribe those thoughts to.

Argument from authority or appeal to authority aren't fallacies by definition, but only when a premise therein is flawed.

The "rocket scientist" that is responsible for landing the craft previously worked on NASA's SMAP satellite, on the control team. One challenge faced with controlling that satellite was that several systems had to share an antenna for different purposes, and the hardware needed to be steered as part of its scanning duties. Dr. Lars Blackmore (said rocket scientist) has authored many papers on control systems, several of which discuss communications as part of it.

I would submit as my "argument from authority" (appealing to Dr. Blackmore's authority) that this particular rocket scientist is likely to have ruled out the ideas posited by any given armchair quarterback engineer, a role I know many of us like to play. The premises behind the argument are not in danger of being flawed, that I can tell; my conclusion may be, but that would just be an everyday incorrect conclusion and not an outcome from a logical fallacy.

Argument from authority is always a fallacy. Your conclusion may be correct, but it is not because an authority says so.

Commenter wants to know why they are being downvoted and the response to them gets downvoted. Nice.

>I asked a legitimate question. Down votes don't teach people who want to learn, people.

When "have you guys always screwed up this way" is your only non-rhetorical question, I call shenanigans on intent to learn. You solidly earned that downvote by being so patronizing.

That said, it's very easy for a solution to be both painfully obvious and at the same time not worth the effort. The rocket scientist is busy doing rocket science. If they give a flippant answer, it's okay to point out that the answer is flippant. It's not condescending. It doesn't imply they are "not aware" of the solution. They simply lack infinite spare time to implement every solution to everything.

I didn't say screwed up. I even suggested it may be done unknowingly and presented that I struggle with "would it be helpful to point it out" vs "am I just magnifying the downvote arrow".

My child has pragmatic communication issues, and I've experienced that he (and others, adults and children alike) generally appreciate being told when they're speaking in a manner that suggests superiority even when I know they're not intending to sound that way. On the other hand, people who are just arrogant will become hostile. That's my gamble, and my question would help me to quantify the nature of that gamble.

Many people in certain segments of information technology, for example, are frequently challenged by social cues and pragmatic speech. I don't know if those groups are more concentrated here versus, say, in a community focused on space. And I don't like to piss off the communities that I have enjoyed being a part of. I learn from mistakes and, when I'm not sure, I ask.

Please don't project a hostile intent; I didn't accuse anyone of anything negative and I was sincerely trying to better understand the people in this community because, for better or worse, I identify with it.

Are you absolutely sure? I cannot imagine a way to read your first line about literal rocket scientists in a non-hostile way.

Yes, of course I am. Why would I lie?

The term "rocket scientist" is often used euphemistically, and I wanted to make sure my usage of the words rocket scientist could not be interpreted any way but literally. Perhaps the phrases "he's no rocket scientist" or "it ain't rocket science" aren't used in the milieu of the community here? I know humor is generally dismissed in this community, but if there is an in-built assumption that euphemistic language isn't expected either, then I can certainly see how my use of literal could be misinterpreted.

That term is not why I found it hostile. It was just a way to identify the sentence. "I'm sorry, but is it possible the expert professionals have given it more thought than you've given it credit for?" is similarly bad. I cannot figure out any way to read it that isn't extremely condescending.

When you ask if it's possible that [insert conclusion], when your conclusion is worded as to be super obvious and something your conversational partner really should have thought of, you're not writing the nicest sentence in the world. When you add the "I'm sorry, but", well, you're not actually apologizing for anything. A non-apology is one of those polite veneers that are put on sentences to pretend they're not insulting. Which magnifies the condescension.

Or just a flying army-like drone that would point to the barge, flying from a distance ?

this is a no-no unless you get some serious telephoto hardware so you can get a good image from outside the no-fly zone. which has been done when the landing was happening in the daytime; not sure if the aircraft was manned, but there are aerial movies of a past failed attempt.

It would make sense to record it in high quality while streaming lower bandwidth signals and, as soon as possible, send the original recording through the uplink.

I like how your imgur post is a proxy for the number of people that view HN.

Probably 1/10th the viewers clicked the link. The link is at about 6k views in 2 hours. Kind of mindblowing how much viewership a toplevel comment gets, especially compared to the number of upvotes/downvotes.

Tell me about it - never thought I'd be this excited about something landing on a floating platform!

I just love SpaceX skill in quantum mechanics

http://imgur.com/StUjcAc Maybe, maybe not

They need a bigger barge with more powerful station-keeping, and a dynamically stabilized hydraulic landing platform. (Along with a gimbal-stabilized uplink dish.)

I don't think any of the landing crashes so far have been due to the barge's size or movement. It's always been problems with the rocket, not the barge.

It's hard to tell really. If the barge was bigger it basically means more leanient constraints for the final approach, which could result in a softer landing. Remember that Falcons can't hover and thus have to achieve perfect timing for the final burn. If you constrain time down to almost zero and space down to a few meters and the initial velocity is terminal velocity + pretty fast horicontal movement, it's almost a wonder that they're already doing what they're doing.

The causes of the earlier failures were insufficient hydraulic fluid, a sticky valve, and a landing leg that didn't lock. I don't see any of those being helped by a bigger target.

Last time it effectively landed correctly in pretty rough conditions. The only problem was a landing leg did not lock because of ice and the stage was lost.

You're probably right. If they needed that stuff they'd probably build it. But I bet that what I suggest would result in being able to land in rougher weather with better media from 1st stage landings.

I imagine so. I'm not sure how much they care about the satellite feed, but handling rough weather would definitely be a plus. There was already one landing attempt that they had to give up on because weather was good at the launch site but bad out at sea.

Why arent there literally hundreds of GOPRO cams on the droneship?

I mean they can make a robotic rocket and sea-based-landing platform, but they cant take good video with $100 cameras? Why are all vids cut off as if it was some lame redditor's crappy gif repost?

Edit: I was clearly misinformed. My question was bad and I feel as.

The problem as I understand it is not the cameras, as we generally get footage later. It's that whole "bandwidth" thing when you're 600km out to sea and a 14 story rocket comes flying in and messes up your satellite uplink.

They have GoPros all over, and they usually release video afterwards from them. The problem is not the cameras, it's the uplink. Turns out cellular signals aren't so strong several hundred miles out to sea, and satellite uplinks are a bit iffy when your dish is being vibrated by a rocket.

Ah, well I was interested in longer content even delayed by days...

They're aiming for 6:35 ET, from the page:

We’re targeting today, Friday, March 4 at 6:35pm ET for launch of SES-9. The window extends to 8:06pm ET. The SpaceX webcast is scheduled to go live here (on http://www.spacex.com/webcast) and on YouTube about 10 minutes prior to launch. For rocket views, launch countdown audio and telemetry info, use this link for our technical webcast: https://www.youtube.com/watch?v=sIkPP2LM8DU

Did I see video footage of inside the fuel tank?

Pretty sure it was actually the LOX tank. But yes.

Ahh, thanks for clarifying!

Another successful Falcon 9 launch. Too bad about the booster landing. The barge landing is very tough; it requires drastic maneuvers in the last seconds to hit that tiny target. The land-based landing pad is much larger.

The Falcon Heavy launch was supposed to be next month, but that's slipped to late 2016, maybe.

Nice "intermission" music.

I'm glad the launch is going well. After all those false starts a first stage failure would have been depressing.

The only question that matters right now is: did stage 1 land successfully on the barge???

Unless you're SES, in which case the remaining 2nd stage stuff is pretty important.

After all that's what they're getting paid for. They can crash a dozen more stage 1's and they're still making money. If only other startups worked that way.

This is just a friendly reminder to everyone that if the first stage did indeed crash, this is merely what every other rocket does every time on purpose. I'm sure you all know this, but sometimes we momentarily lose that context.

I doubt if anyone forgot that rockets aren't reusable. What was said to make you think you needed to remind people of something everyone already knows?

"they're still making money. If only other startups worked that way." is the part that prompted the reminder.

Imagine someone saying the same thing about a delivery service throwing boxes away. They're not burning money and getting away with mass failure. It's a perfectly ordinary way of handling things.

At over 13 years old, SpaceX is many things - but I don't think it can really be called a startup anymore.

This gets mentioned lot, not just with spaceX but other similar sized organizations as well . It is simply not true, for two reasons

a) The scales are not the same in aerospace as in software, they are still very much the minnows in that industry.

b) It does not matter if they have 5,000 staff or $1+ Billion revenue today,What matters is the high growth plan they are following, In the next 10-15 years they could be easily doing $100 Billion + i.e. if they are successful with cost costing and can expand the market for it support companies of that size.

Any company looking to 100x or more their revenue is a startup. Size notwithstanding, simply because whatever they do now will be nothing similar to what they need to do to get the remaining 99%. Every single business and technology process would have to be continuously innovated and thrown out to get there. That really requires a startup mind frame and startup culture

It also has 5000 employees...

It looked like it was somewhat off-center just before the video froze. Hope I'm wrong.

It intentionally comes down a bit off center so that if the engine(s) don't relight, the rocket crashes into the ocean instead of the ship. It then maneuvers onto the ship from there. The video may have just cut off before that.


We detached this subthread from https://news.ycombinator.com/item?id=11228607 and marked it off-topic.

>The point I wanted you to make is that some company is developing a great new technology while running a profitable business. If robotics, self-driving cars, clean energy, etc could do the same, we'd all benefit.

That's a perfectly nice point, but it's also obvious. Were you stating such an obvious thing "because we're all a bunch of fucking idiots"?

Your original post's wording really seems to be wishing other startups could get away with that kind of waste as long as their core product is good, not wishing they were trying to massively eliminate waste.

Nope, everyone knows that landing the first stage is an incredibly difficult problem to solve, right? I was simply saying that they have a lot of time and money to solve it because they have a profitable business that doesn't depend on them solving it. Lots of startups are VC backed long shots. Most startups fail because they run out of money. It seems to be the way the market is played these days. SpaceX is kept private, for example, so it doesn't have to be held hostage by public markets. That's rare for most companies.

Are you really trying to blame me for an argument you got yourself into with someone else? Way to go indeed.

You're the person with the "friendly" reminder stating the obvious. Try to remember me and avoid adding pointless comments.

If a friendly reminder of the obvious causes you to go nuts and start an argument with a stranger, that's a problem with you, not me.

Just trying to correct a problem. The level of discussion will never rise if people don't make more of an effort. Placing the words "friendly reminder" doesn't change the fact it was a stupid comment. As a friendly reminder, try not to restate the obvious and help raise the level beyond noise. Most threads read on this site add little value and nothing is to be learned from them. Can't we do better?

By the way, here's our discussion where you thought you needed to explain why SpaceX is landing on a barge:


Do you think I don't understand why SpaceX is using a barge in the ocean? I'm trying to dig deeper and you seem to be stuck in the mundane.

All I see there is a very poor understanding of SpaceX's approach. The moment you mention hovering, you've shown you don't know what they're doing. And this is supposed to be an argument against stating the "obvious"??

I was providing you with another example of you adding zero value. I wasn't trying to limit the conversation to SpaceX's current approach. I was attempting to have a broader discussion of possibilities.

You seem to enjoy the more mundane, which is fine. However, I'm really trying to drive home the point that some people want more. Perhaps you can take notice and not insert drivel into conversations?

Even if stating the obvious is a sin (and I'm not convinced), it seems way less of a sin than starting gigantic unproductive arguments, or asking questions without doing the most basic of research first.

If you want to raise the level of discussion, look at the beam in your own eye first.

Certainly I'm not helping by continuing to grow this gigantic pointless argument, so I think this will be my last post here.


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