SpaceX - The Quest For Mars


#281

Ha ha, thanks for running the numbers on it


#282

SpaceX just launched and landed another 1st stage today. It’s becoming meh! at this stage.

What was different about this launch was the amazing footage of the 1st stage coming back. It was incredible to watch, lots of closeups of the 1st stage as it fell back to Earth. I’ll post something once a find a good mashup of the sequence.


#283

I don’t know how to post this as an embedded video but this is a link to the incredible footage from today’s launch / landing

instagram.com/p/BTjVdLVB1bO/


#284

Also, a three legged system is self-levelling, but not always in a good way. (Try sitting on a three legged stool. It will never wobble, but, you might not always be sitting upright). Should a three-legged support shift slightly, your rocket will still be stable, but no longer pointing in the correct direction. On a four legged support, your accelerometers will immediately tell you that something is wrong if the system is moving. (This assumes that the supports are rigid, of course.)


#285

Here’s today’s full sequence … a thing of beauty. It’s fun watching the speeds on the telemetry (and estimating the accelerations) during the landing phase. I’d either forgotten or hadn’t realised that the booster rises to an apogee at more than double its separation height – from about 70 km to 166 km – before hurtling back to 4 km in just 200 seconds. Were it not for the entry burn and air resistance the free fall time would still be over 180 seconds, which makes you realise how finely tuned the whole operation is. The landing burn starts at 4 km, 30 seconds before touch down.


#286

It just doesn’t seem possible, they always land it in the centre of their logo aswell, it would seem more realistic if it came down somewhere random in the desert or Sibreia or somewhere. Great shot of it coming down at 20:38 in that video.


#287

Rumours of a SpaceX IPO later this year being denied: nasdaq.com/article/spacex-pr … 0503-01141

I’d be sceptical myself, the business is generating a lot of cash, and Musk has said several times that he hates the idea of being beholden to Quarterly reviews like he is with Tesla.

That said a Ton of cash would help accelerate his Mars plans.


#288

Attempting to split the conversation from the Tesla thread.

Exactly right now I’m on a plane on wifi that is using a Geostationary satellite located 38,000km away. The latency is perceptible. SpaceX’s sats will be ? 400km away someone correct me.

There is an instant market for airline passengers for the SpaceX service.

It’s fun living in the 21st century


#289

At any given time there are approximately one million people in the air, and most of them are short haul. Today, it was announced that the US is “considering” banning laptops from certain European airports.
In flight internet depends on extracting a lot of money from relatively few corporations/people. I think Musk will try to extract a little money from a lot of people, in much the same way that Jeff Bezos is currently transforming the economic model of the Washington Post, which has overtaken the NYT, in terms of raw clicks.


#290

I think the discussion in the Tesla thread overlooked one factor that will change the latency/price equation, the adoption of the IoT. In 20 years there’ll be billions of new devices connected Not all people, nor all applications want/need/can afford the shiniest new toy.

If my web connected toothbrush, abcX123@.toothbrush is communicating with my dentist, bigdriller@.dentist as to whether I’m following the new rec that flossing is a waste of time, that doesn’t need to be instantaneous, but it does need to be cheap.

Currently, I pay waaay too much for three separate forms of internet access, work, home, and mobile. I was never much of a man for d’oul sums, but if Musk can get 8 billion people to pay “fity cent” a week for non priority access, I think a lot of banks would want in on that action. That’s one part of the reason for why the net neutrality debate has resurfaced in the US, and while I currently support the Obama regs, over time, I can see my position drifting a bit…


#291

T.I. has asked that satellite discussion be transferred from the Tesla thread to SpaceX. I think that makes sense.

In reply to ps in the Tesla thread…

thepropertypin.com/viewtopic.php?p=913266#p913266

I don’t believe that detailed technical specs for SpaceX sats are currently available, probably for commercial reasons. Boeing, and OneWeb are potential competitors. First trial launch is not scheduled until late 17 or early 18, and full rollout not scheduled to be completed until 2024.

arstechnica.com/information-technology/2016/11/spacex-plans-worldwide-satellite-internet-with-low-latency-gigabit-speed/

The 4,000+ SpaceX sats are planned to be between 100-500kg at 7-800 miles.

SpaceX is currently quoting commercial customers between $2,000 and $5,000 per Kg for launch. That’s a max of $2.5M on a 500kg. Presumably they’ll do it for less for their own.

Since the Arstechnica article SpaceX has applied to launch 7,500 sats of its own. Not sure if that is an increase from 4,000 to 7,500, or an additional 7,500.

There are only 60 -70 Iridium sats in orbit.


#292

There’s going to be a lot of space hardware knocking around up there in the coming years.

Whoever cracks the space junk problem will probably make a decent wedge.


#293

I’ve used satellite Internet for two extended periods of more than a couple of years. The first time it cost €1,500 installation and €120/month for 0.5 Mbps. Five years later with the introduction of Ka-band it was €250 install and €60/month for 20 Mbps – an eighty-fold increase in price/performance. The latency wasn’t a showstopper for applications other than interactive video. Monthly download limits were actually a bigger problem.

Given all the things you couldn’t do because of restricted bandwidth, PAYG cellular actually become the more desirable option once 3 and 4g came along. The only reason I was a customer for either of them was because of rural location.

I don’t think a new satellite option is going to attract even lots of rural customers unless it is faster, less bandwidth-restricted, doesn’t need a fugly 1-metre dish, and is much, much cheaper than existing offerings. And to be economically viable I reckon it can’t depend on just rural dwellers and travellers on boats and planes. I think IoT is a red herring too. IoT devices won’t be deciding or caring how their traffic gets routed. Plus fibre has scads of spare capacity. No, Musk will need to capture city city slickers too, including all those apartment dwellers who can’t stick antennae anywhere they please.

That said, if Musk can get launch costs for his 4000 sats down to several hundred million, that’s no more than the cost of a big network rollout in a single large city. The other big question is how he squeezes the bandwidth numbers that have been mooted out of it.


#294

Virgin media internet connection in Dublin city:

It costs 60 euro a month and comes with a phone line. No dish required. No install cost. No bandwidth limit (though reputedly they do throttle uploads for very heavy users sometimes, at least in the UK). And Ireland is not exactly known for the cheapness of its telecoms, and it’s not like this is the best available; there a number of FTTP rollouts at various stages of development. I really struggle to see how the Tesla product could possibly be competitive in urban areas in the developed world.

In principle they could maybe offer a cheap service for very light users, but there the cost of antenna installation becomes an issue, and they’re competing with the mobile telecoms.

It might be possible for them to make some money serving rural customers, but they’re never exactly going to be the biggest telecom in the world doing that, and I would think they’d always be vulnerable to competition from mobile telecoms and WISPs. They could be good for airplane connectivity and things, but that’s a seriously niche market.

RE IoT, I’d think that’s a complete non-starter; IoT thingies usually just use the household’s internet connection, whatever it may be. And for IoTish things placed in places that don’t have an internet connection there’s mobile data (often via specialised ultra-low-cost packages; the epaper kindles get lifetime free cellular connectivity, for instance), and specialised ultra-low-energy low-bandwidth high-range wireless systems (LoRa etc). You also generally don’t want a big antenna.


#295

Why do you believe IoT is a red herring?
The data may not decide or care how it is routed, but the people paying for it may have very strong opinions on the issue. They will likely not want to pay premium rates for the transfer of oceans of routine, mundane, and non mission critical data.


#296

Household connections will account for only a tiny proportion of IoT data. Industrial, commercial, and health care data will be much more significant.
No longer will you need to get a speeding ticket to alert your insurance provider of your driving habits. Your car will automatically transmit that data and they’ll raise your rates if they can justify it.


#297

is it for the better bandwidth for space probes/Mars etc? and more than just earth communication? is it something nasa would pay for access to


#298

Actually that set me thinking - the US has really crap internet in many places, crap and expensive. It may sounds like a good deal there?


#299

You’re assuming that Musk will be selling bandwidth at very cheap rates. But I’ve seen nothing that shows how he’s going to have (practically) unlimited bandwidth. The radio spectrum is a finite resource whether you are using fixed masts or circling the earth. Apart from that, I see no reason why IoT data will be separated out from other traffic for special routing.

Yes, but the population density is lower in those places. It’s the usual problem – the people for whom satellite is the best fit are the tip of the iceberg. Lots of papers on how population distribution follows --depending on which you read – an exponential, power law, or fractal (self-similar on all scales) pattern. Either way, the city slickers will always be the low hanging fruit, and that’s where satellite is less likely to compete.


#300

Does it make sense for this to be sold B2B, to increase coverage of existing networks?

What hardware is required? I assume it can’t be squeezed into a smartphone.