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Space: A sudden light

economist.com

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Re: Space: A sudden light

#21

Post by marcosdumay »

chris_va wrote: post #9

The real problem with the space economy is that there are really very few business plans: - Space Tourism - Imagery Acquisition - Communications - Science - Astroid Mining (pending) ... And it turns out that none so far have been good businesses, and the small sat form factor is really limited. I really really love space stuff, but I don't see any of these creating explosive growth in the short term. Eventually the c…

Asteroid mining is a support business, not an end goal. It's more like selling stoves, it may be lucrative and a big field, but won't make people go to the middle of nowhere by itself.

Some day we'll probably start to send supercomputers into space, but there isn't really any kind shortage here on Earth that this would solve right now.

Re: Space: A sudden light

#22

Post by chris_va »

pjungwir wrote: post #17
chris_va wrote: post #9

The real problem with the space economy is that there are really very few business plans: - Space Tourism - Imagery Acquisition - Communications - Science - Astroid Mining (pending) ... And it turns out that none so far have been good businesses, and the small sat form factor is really limited. I really really love space stuff, but I don't see any of these creating explosive growth in the short term. Eventually the c…

I keep daydreaming about what a killer business might be. A few other ideas that probably won't pan out but are interesting to think about: - Since nuclear reactors are dangerous, what if we build them on the moon instead? Is there any way to generate energy there and get it back to earth? - In The Moon is a Harsh Mistress the moon-dwellers fight earth by hurling rocks (maybe just threatening?), which strike with mor…

- Zero g manufacturing (good edit, has some potential)

You have something with the spaced based solar (SBSP). The unsolved problem there is the microwave power beaming, which has some technical hurdles (synchronizing microwave frequencies across multiple dishes is apparently hard, but necessary for power beaming, and there is an ozone problem). Any other space based power system has this same transmission problem (people have proposed attaching conductive tethers to orbiting NEOs to drag through the magnetic field).

The "nuclear reactors are dangerous" bit hasn't really been true in a long time (Chernobyl was the worst disaster, but killed a lot fewer people than hydro/coal/etc).

Space is actually not great for computers. Dielectrics change in vacuum, and cooling is actually a big problem (turns out space isn't actually "cold" in the traditional sense, it is insulating, and heat tends to build up). Quantum computers are probably a red herring, there is vey little difference on an atomic scale in/outside of micro-gravity.

Re: Space: A sudden light

#23

Post by mikeash »

chris_va wrote: post #18
mikeash wrote: post #16

Earlier quoted context omitted.

Now you're changing from "so far" to attempting to predict the future, which is rather different. As far as the future goes, throughput and latency both improve dramatically with low-orbit systems. Cost is high (see the massive failure of Iridium to see how that can go) but is coming down pretty rapidly right now. And given how many satellite dishes I see on buildings in cities, it seems that there are use cases beyo…

Mostly fair, but... Latency to space is always going to be slower, as you are going to add a few hundred miles, and power requirements for high-bandwidth applications require large solar panels which are incompatible with low-altitude sats (too much drag). Then there is also a problem with non-geo sync orbits and directional antenna tracking. This is actually a huge problem. Current small sats point directly at their…

Lower launch costs make drag less of a problem, since you can give the satellites more fuel for reboosts. A few hundred miles of latency is no big deal. 200 miles adds one millisecond of latency. The speed of light is noticeably slower in fiber, too, so that balances out once you get past a certain distance.

Talking to one receiver at a time is clearly not an inherent limitation of low-orbit satellites. Iridium satellites can handle multiple simultaneous connections without directional antennas on the ground side, and with a phased array on the satellite side.

I'm well aware that dishes are pointed at geosync satellites. The fact that there are so many in areas with good coverage from terrestrial radio and cables means that there are applications beyond filling gaps, even with the latency that geosync implies. I don't recall ever seeing a satellite dish pointed horizontally, and certainly all the little ones I see on houses aren't, so I completely don't believe that "half of those" figure.

Re: Space: A sudden light

#24

Post by chris_va »

ChuckMcM wrote: post #19
chris_va wrote: post #9

The real problem with the space economy is that there are really very few business plans: - Space Tourism - Imagery Acquisition - Communications - Science - Astroid Mining (pending) ... And it turns out that none so far have been good businesses, and the small sat form factor is really limited. I really really love space stuff, but I don't see any of these creating explosive growth in the short term. Eventually the c…

I would agree this is generally true. There isn't anything that is easier to do in "space" than it is on the planet. But I think that might not be as true for other planets. You could, for example, put radioactive waste in an open pit on the moon. Nobody is going to "accidentally walk by it unprotected" as the radiation levels on the surface of the moon are "naturally" higher than anything we've got in our waste pile…

If you can get it to he moon, may as well put it in the sun :).

There is a slight problem with the x% chance the rocket will blow up at max-Q while still in the atmosphere.

Plus, all nuclear waste ever generated would fit in 1 football stadium. The rest of the spending is just due to political infighting that looks good to voters.

Re: Space: A sudden light

#25

Post by chris_va »

mikeash wrote: post #23
chris_va wrote: post #18

Earlier quoted context omitted.

Mostly fair, but... Latency to space is always going to be slower, as you are going to add a few hundred miles, and power requirements for high-bandwidth applications require large solar panels which are incompatible with low-altitude sats (too much drag). Then there is also a problem with non-geo sync orbits and directional antenna tracking. This is actually a huge problem. Current small sats point directly at their…

Lower launch costs make drag less of a problem, since you can give the satellites more fuel for reboosts. A few hundred miles of latency is no big deal. 200 miles adds one millisecond of latency. The speed of light is noticeably slower in fiber, too, so that balances out once you get past a certain distance. Talking to one receiver at a time is clearly not an inherent limitation of low-orbit satellites. Iridium satel…

Sorry, didn't mean to imply that your argument was wrong.

For Iridium, the total bandwidth per satellite is really really low (like 28.8? Newer ones might be higher), and they had to put them slightly higher up (500 miles, I think?) to avoid drag issues since they needed bigger solar panels.

The latency thing is more compared to microwave beaming, which is how most cell backhaul is done now, but you are right that the extra few hundred miles isn't critical (my head was still in geo-synch).

Re: Space: A sudden light

#26

Post by TeMPOraL »

pjungwir wrote: post #17
chris_va wrote: post #9

The real problem with the space economy is that there are really very few business plans: - Space Tourism - Imagery Acquisition - Communications - Science - Astroid Mining (pending) ... And it turns out that none so far have been good businesses, and the small sat form factor is really limited. I really really love space stuff, but I don't see any of these creating explosive growth in the short term. Eventually the c…

I keep daydreaming about what a killer business might be. A few other ideas that probably won't pan out but are interesting to think about: - Since nuclear reactors are dangerous, what if we build them on the moon instead? Is there any way to generate energy there and get it back to earth? - In The Moon is a Harsh Mistress the moon-dwellers fight earth by hurling rocks (maybe just threatening?), which strike with mor…

> Since nuclear reactors are dangerous, what if we build them on the moon instead? Is there any way to generate energy there and get it back to earth?

Any way of bringing down lots of beamed energy from the Moon could be also used as a weapon of mass destruction[0], so I imagine we first need to sort out terrestrial politics before this has a chance of catching on.

[0] - possibly quite surgical, as WMDs go.

Re: Space: A sudden light

#27

Post by blackbagboys »

api wrote: post #4

This is notable because The Economist penned this a few years ago: http://www.economist.com/node/18897425 Of course economists are on par with Ouija board users at predicting the future.

The typical Economist staff writer is probably a 25-30 year old journalist with a B.A. and a prestigious-sounding alma mater, not an actual economist.

Re: Space: A sudden light

#28

Post by pjungwir »

chris_va wrote: post #22
pjungwir wrote: post #17

Earlier quoted context omitted.

I keep daydreaming about what a killer business might be. A few other ideas that probably won't pan out but are interesting to think about: - Since nuclear reactors are dangerous, what if we build them on the moon instead? Is there any way to generate energy there and get it back to earth? - In The Moon is a Harsh Mistress the moon-dwellers fight earth by hurling rocks (maybe just threatening?), which strike with mor…

- Zero g manufacturing ( good edit , has some potential) You have something with the spaced based solar (SBSP). The unsolved problem there is the microwave power beaming, which has some technical hurdles (synchronizing microwave frequencies across multiple dishes is apparently hard, but necessary for power beaming, and there is an ozone problem). Any other space based power system has this same transmission problem (…

Ha ha I knew someone would point out that vacuum isn't "cold", because lack of matter means heat can't transfer away from hot things. My comment about superconductors and computers tossed a bunch of stuff together I probably should have separated. I agree space wouldn't help for cooling conventional CPUs. Would it still help for superconductivity? (I have no idea.) Also for quantum computers I was wondering if vacuum would have any benefit for decoherence.

Re: Space: A sudden light

#29

Post by mikeash »

chris_va wrote: post #25
mikeash wrote: post #23

Earlier quoted context omitted.

Lower launch costs make drag less of a problem, since you can give the satellites more fuel for reboosts. A few hundred miles of latency is no big deal. 200 miles adds one millisecond of latency. The speed of light is noticeably slower in fiber, too, so that balances out once you get past a certain distance. Talking to one receiver at a time is clearly not an inherent limitation of low-orbit satellites. Iridium satel…

Sorry, didn't mean to imply that your argument was wrong. For Iridium, the total bandwidth per satellite is really really low (like 28.8? Newer ones might be higher), and they had to put them slightly higher up (500 miles, I think?) to avoid drag issues since they needed bigger solar panels. The latency thing is more compared to microwave beaming, which is how most cell backhaul is done now, but you are right that th…

The current Iridium satellites are ridiculously slow. They were designed in the 90s for voice, and having any data capability at all is sort of an afterthought. One "call" is a whopping 2400bps. Each satellite can support 1100 calls simultaneously, but even if you ganged them all together that's still only 2.6Mbps total.

Iridium NEXT is going to start launching in September and will have vastly better capabilities, up to 8Mbps per connection. Still not great compared to a terrestrial wired connection or even modern cellular connections, but a lot better. If launch costs drop significantly, you could presumably do a lot better still.

Re: Space: A sudden light

#30

Post by ChuckMcM »

chris_va wrote: post #24
ChuckMcM wrote: post #19

Earlier quoted context omitted.

I would agree this is generally true. There isn't anything that is easier to do in "space" than it is on the planet. But I think that might not be as true for other planets. You could, for example, put radioactive waste in an open pit on the moon. Nobody is going to "accidentally walk by it unprotected" as the radiation levels on the surface of the moon are "naturally" higher than anything we've got in our waste pile…

If you can get it to he moon, may as well put it in the sun :). There is a slight problem with the x% chance the rocket will blow up at max-Q while still in the atmosphere. Plus, all nuclear waste ever generated would fit in 1 football stadium. The rest of the spending is just due to political infighting that looks good to voters.

Yes, there are risks. Just saying its a defensible "permanent" solution to disposing waste with a very long half life.

As far as using the Sun as an alternate, it takes less delta-v to get to the moon than it does to get to the Sun.

Further, the overall effect of adding nuclear waste to the Moon is completely predictable in its impact, but that is less true of adding it to the Sun.

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