Nibb31

Hermes was cancelled well before the actual design work started on Ariane 5. It isn't man-rated. Considering the cost of JWST and Proton's reliability these days, that would be a bad idea. The Ariane launch is provided by ESA as part of a barter arrangement. Basically, it's free for NASA.

That would depend on the extent and cost of the totat redesign it would take to make it cheap and reusable. It could never have been cheap and reusable in its existing form.

Beyond drag issues, the limiting factor will be shelf life of components. Metal structural components, plastics and rubbers in covers and seals, filters, gasses, fluids and lubricants... All these things age and will end up failing. Solar panels have a working life of approximately 20 years. You couldn't leave a station powered-down and mothballed and expect it to power up with a breathable environment after several years. After a while, you will necessarily have leaks, The atmosphere would become unbreathable without proper filtering, polluted by leaking fluids, flaking paint and insulation, or bacteria. If the atmosphere leaks, any system that isn't vacuum hardened inside will be destroyed.

Yes, but really what matters in the picture is the cost of the entire system, not the cost of the individual satellite. Development through trial and error is a bad process that typically entails budget overruns and waste. I really can't see SpaceX launching these birds. OneWeb is a direct competitor to SpaceX's own constellation and they wouldn't delay their own project when being the first-to-market is going to be crucial. They are going to have to go with a more traditional launch provider or find a really really cheap alternative (good luck with that!). Not the numbers I've seen. OneWeb claims the total cost of the project to be between 1.5 to 2 billion. I can't see how they could get 25 launches for less than a billion. If they are paying 1.4 billion for the satellite contract, they are already over budget. And there is still the commercial service to set up. Given that we are talking about Airbus Defense and Space (ex-EADS Astrium), don't get your hopes up too high...

You can get energy out of a pressure differential. However, you need more energy to create that pressure differential in the first place. The efficiency of the system will be very poor.

Well, since they are basically reinventing the wheel in terms of how a satellite is built, it will actually require more design team/production team people to not only design the new satellites using new methods, but also to source the new parts from new suppliers, layout a new manufacturing chain, and come up with new and innovative procedures to reduce man hours. Instead of relying on established infrastructure and practices that are used in the industry, Airbus DS is going to have to throw away 50 years of experience and rethink vertically and horizontally the entire satellite industry from scratch. That is not going to be cheap or easy. And since this is going to be pretty big production run (by industry standards), they can't simply try completely unproven solutions with certifying them through rigorous testing. They would need to be sure that your 5 system-on-chip CPUs or your on-board wifi works in space before committing the design to 900 satellites, because if one of those cheap systems fail on the first batch, then you have to rework the whole design, which will cost more in the end. So at the end of the day, those cheaper systems still need to have some sort of certification process before you can include them in the design.

A black hole is not a hole. It's a very very very heavy object. So heavy that its own gravitation pull has caused it to collapse on itself, making it very very very dense. It's so heavy that it attracts all the matter nearby to crash into it, making it even heavier and its gravitational pull even stronger. It's so strong that even photons can't escape, which is why we can't see it.

Probably a silly question, but... I'm buying a UPS for my NAS/home server and the one I'm eyeing has RJ45 connectors for surge protection of data/phone lines. However, I get TV/Internet/Phone from a buried fiberoptic connection. The FO cable arrives at a converter box inside the house that has an RJ45 connector that goes to the router. Would there be any benefit in putting the UPS surge protection between the converter box and the router? My gut feeling is no, but you never know...

Absolutely. The fact they plan 200 spares for a constellation of 700 sats indicates that they expect a very high failure rate (nearly 30%!), therefore they are willing to take cuts in quality control and reliability. My point is that it is a huge shift that completely changes the way a company like Airbus does business. The 25% failure rate is scary, because these sats are designed to be at an orbit of approx 700 to 1000km, where there isn't much drag to deorbit them if they fail. Any sat that doesn't deorbit will become a debris hazard. As a comparison, it's equivalent to the number of A330 aircraft produced or it's twice the number or Eurofighters. It's a pretty large production run for the aerospace industry, but fare from anything the space industry has ever done. - - - Updated - - - You need at least one launch per inclination. A decent spread for ~700 sats would be something like ~26 satellites on ~26 different inclinations or a similar combination. That would mean ~26 launches of 26 sats that weight 150Kg each, meaning that if you add the weight of a dispenser, a launcher in the 6-tons-to-LEO class like Soyuz or Angara could do the trick. But then you start hitting schedule bottlenecks. How many Angaras or Soyuz can be produced every year?

That's not how satellites (or even mass-produced aircraft) are built. Individual parts can be produced by machines, but assembly, wiring, and testing is a very involved manual process. In addition, spacecraft are built in a clean room, which is expensive. Making a production run for 900 satellites is going to require a paradigm change for Airbus (or any other aerospace company). It also means that standards are going to be lower than what is in practice in the industry. This means lots of engineers working on new processes and standards, finding and certifying new suppliers, building and laying out production lines, etc... It also means that the sats have to be designed for cheap assembly, which has never been done before. Basically, this is like creating a new industry from scratch. There is no way it's going to cost just a few million dollars. Unfortunately, no. Typical production runs in the satellite industry range from 1 to 10 or 20 units. For typical comsats, Boeing or Airbus offer standard satellite busses that carry the propulsion, power, and avionics, and the customer adds antennas and transponders as required. However, those are still small volumes of large and expensive satellites (several tons and several $10 million). As an example, for small runs of metal parts, it makes sense to mill them (or even 3D print in some cases). When it comes to larger production runs, casting those parts becomes more economical (you make a mold, which is expensive, but the unit cost is much lower than CNC milling). The problem is that your usual suppliers might be tooled for milling. Buying larger batches means that either your certified aerospace supplier has to invest in a new production line for casting, or you need to certify another supplier to aerospace standards who is already capable of meeting your volume.

Because there is no existing production line in the world that can manufacture a production run of 900 small satellites. Existing satellite manufacturing facilities have a capacity or 1 or 2 units per year. I also don't see how you could set up such an infrastructure from scratch at a cost of only $400000 x 900 units. I've read unofficial numbers of $1.4 billion for the Airbus DS contract, which is more realistic, but it also doesn't fit with OneWeb's claimed budget.

I agree, it wouldn't make sense to expect 700 launches from Virgin, but even if they get 50 launches on SpaceX's manifest (which I doubt they will because SpaceX is a direct competitor), that's still way over their total $2 billion budget.

It looks like Airbus DS is getting the contract for developing and building the OneWeb sats. 10 preproduction models will be built in Toulouse, France, and the series production will be in a purpose-built factory in the US. The figures I have are that the order is for 900 satellites for $1.4 billion. The constellation will have 700 sats and the remaining 200 are spares to replace failed birds. One of OneWeb's investors is Richard Branson, so it seems like they plan to use LauncherOne to launch the satellites. LauncherOne is supposed to be sized to launch up to 200kg to LEO on a small expendable rocket for "under $10 million". I can't see how 700 individual launches can ever be cost-effective... The total cost of the project is estimated at $1.5 to 2 billion, and OneWeb has said that they didn't want to pay more that $400000 for each sat. Although we don't know the amount of the Airbus DS contract, I doubt they would bother for only $360 million, that's small change for them (it's the price of a single A380). If you add the cost of the ground infrastructure and setting up the commercial service, the numbers simply don't add up.

Not true in Europe at least... You can get low bandwidth (1Mbps) DSL practically anywhere you have a phone line. Where you can't get it, you can get satellite or 3G. 4G is still only for urban areas, but it's expanding to smaller towns. Satellite internet is still a niche in terms of population coverage, and therefore marketshare, and it's not necessarily growing. It's going to be hard for OneWeb or SpaceX to compete with established operators, and they won't go down without a fight. - - - Updated - - - You're right, but it's notoriously difficult to do business in those countries. There are political, cultural, and legal barriers. You need to set up billing and customer services for all sorts of currencies, and you also need to make sure your service is affordable. It's not an easy combination, which is why companies like Google or Amazon don't do business in many of those countries.

I understand that, but that is becoming more and more of a niche market. You can get decent internet pretty much everywhere in Europe and America. There are existing offerings for satellite internet, but that's a shrinking market as 3G and 4G expand. There are also niche markets like aircraft or ships, but those are small. The areas with little internet coverage these days are mainly developing countries, which are hard to do business with. In fact, the reason people don't have access to the internet nowadays is more about affordability than a problem of coverage.

Europe converted to the Euro and there wasn't much of a revolution. Canada and Australia converted to metric, and there wasn't much of a revolution either.

This isn't news. It was actually announced before SpaceX's constellation. I really don't see how these constellations can compete commercially with existing offerings (4G, fiberoptics, DSL, etc...), let alone among themselves.

That's a bit of an urban legend. One of the people on the team calculated that the shaft cover of the nuclear test would be launched into space, however chances are it was obliterated during the test.

The reason for using 24-hours goes back to the ancient Egyptians. They divided the day into two equal parts, night and day, and then divided each part into 12 hours. The duodecimal system was popular in ancient times, because 12 can be neatly divided by 1, 2, 3, 4, and 6. It also fitted the Babylonian system of dividing the circle (and thus Earth's rotation) into 360 degrees. The beauty of 360 is that it can be divided by pretty much every number from 1 to 10 except 7, which is a huge advantage. - - - Updated - - - 57 kilograms. That was easy. No idea how much it would weigh in pounds without pulling out the calculator.

There's already a thread here: http://forum.kerbalspaceprogram.com/threads/124524-Rare-photos-of-survived-Burans

Yeah right, your house is sitting on a gold deposit in Wilmington, NC, but it's not worth picking it up. Believe me, if that was true, someone else would be picking it up and you would not be living there.

Spacecraft are not Lego. Rockets don't work that way. Buran doesn't have engines. It has the equivalent of the Shuttle's OMS thrusters. It was launched on the side of a huge Energia rocket. Its structure is designed for sidemount launch loads, not thrust from the rear end. It weighs 80 tons, so even if you filled it to the brim with propellant it would not make it to orbit. It would need something the size of SLS to get to orbit. Half a billion dollars wouldn't even pay for the trade studies. Old unmaintained space hardware is worth zero as a spacecraft. It can go to a museum or on display as plane-on-pole at Baikonur spaceport, but that's it. It's dead Jim.

There isn't that much secrecy. The problem is that western media doesn't relay much of what's happening in China.

It would be pretty hard to hide a manned orbital program. It would also be pretty useless.

Titan was super-expensive too. Those hypergolics (hydrazine and UDMH with nitrogen tetroxide) were really nasty and required lots of specialized handling procedures and equipment that boosted the cost.