OTU Only: Satellites sometimes obsolete in the OTU?

[CosmicGamer]

I like them too, but I wonder how the cost and maintenance of a large number of airships would compare to the cost of satellites.

This can vary by planet. Again is the issue regarding some planets possibly not having the capability to put satellites up themselves.

With our very limited space going capability it seams for whatever reason, satellites are the way to go. Last thing I read was that a typical satellite was 50 million to $2 billion (US) but some private Co. claims they will be able to build and put one up for under $1 million. Not a communication satellite. Solar powered, cameras, a geiger counter, a spectrometer, a magnetometer, data transceiver, and remote control from earth. Definitely not milspec and only expected to stay up a couple years. I guess cheaper to just build another and send it up than to equip it with propulsion to maintain orbit or to pay for someone to grab it and pull it back into position (is that possible any more without the shuttles?).

I'd think once space traffic is more common that it would be much more cost effective.

Just get whatever ship is passing through to put a couple in it's airlock and push it out? Wouldn't even count as cargo cost.

 

[robject]

That computer is still going to need data points to work from. You have to see a celestial body, in any weather, to navigate by. You don't have to see a GPS Satellite.

I'd be most happy to have such a computer, weatherproofed and easily rechargeable!

On top of that, a human must accurately take the measurements and input them. Garbage in = garbage out.

This is interesting. Let's work out the hard limits to this. The big one is being able to see identifiable celestial bodies, which may be obscured by weather or sunlight.

Data is critically important too, but that could be a job for the IISS.

An easily recharged, ruggedized, cheap computer is similarly no issue for Traveller.

Correct usage requires three things: visibility, human training, and ease of use for the equipment.


Bottom line, if you don't have celestial references and you lack the skill (or your computer is obnoxiously hard to use), then you're SOL. That doesn't sound like a problem so much as it sounds like an adventure scenario.

 

[BytePro]

Not good enough to navigate from.

I was not discussing navigation.

There is some truth in this. It is however a localized situation, not global.

Latency for geosync satellites is a global issue as long as ones comms are not FTL.

My supertanker will try really hard not to hit any of your thousands of ocean towers. Especially during storms when I can neither see nor hold an accurate course.

:rofl: Come now, supertankers primary navigation method is visual? LMAO.
Man made structures, such as the over 500 oil rigs today, use RF for collision avoidance. A few thousand towers in something the size of the world's oceans is hardly going to pose a navigational hazard.

They still can't hold position for accurate navigation. They don't lift a whole lot of weight either. Until you find an elemental gas with better lift properties than hydrogen.

Well, I wasn't proposing airships for navigation - accurate or otherwise. However, it should not be hard to realize that an airship can, in real time, know its relative position from fixed ground points extremely accurately and encode that into positional transmissions.

As to airships not being able to 'lift a whole lot of weight', that is incorrect - not to mention not relevant to their use of air current and solar energy, nor isotope reactors (as on space probes). That they can't lift a lot proportionately to their size should go without saying.

Space-based radio-positioning ala GPS is great, but is not the sole use, nor even the initial justification for satellites. Commercially it was highly restricted until after the KAL 007 incident (and intentionally less accurate till after selective availability was rescinded). There are other systems that would work more than well enough for modern societies. The U.S. military justified the expense of the Navstar system during the cold war for ICBMs, but it also pursued it reduce the numerous different navigation methods of the day.

EDIT: While weather can deter celestial navigation, it can also interfere with satellites. Many many times a year my dish for internet, dish for TV, and car GPS says it can't find a satellite in bad weather. No system will be perfect. Is it not possible certain atmospheres would preclude not only celestial navigation but the use of satellites too?

Yes - though there are lots of band one could use*. One could image environments were any transmissions would have to compete with extreme interference.

(*BTW: military bands (in portions of C vs the more common Ku) suffer much less from the rain/snow fade consumer issues you relate. There is also an issue of allowed power to avoid terrestrial interference. Lift those restrictions and satellite becomes a lot more reliable.

Also, while 'selective availability' was rescinded for U.S. GPS, consumer accuracy is still around 40 feet or so, IIRC (maybe better with some differential GPS methods), while military accuracy is measured in, er, fractions of a foot.)

I like them too, but I wonder how the cost and maintenance of a large number of airships would compare to the cost of satellites.

Well, satellites are very expensive to build, launch, maintain (via earth based monitoring and adjustments) and replace. The HS-601, one of the most popular birds in the later '90's, generally cost $150-250 million just for the satellite.

If an infrastructure and market were established, airships could cost substantially less than satellites, even accounting for reduced terrestrial footprint.

Bear in mind, satellite launches and in-orbit failures are rarely (if ever?) insured. I know back in my day Loyd's wouldn't insure them.

[Sorry for long post - prior post didn't...]

 

[BytePro]

This is interesting. Let's work out the hard limits to this. The big one is being able to see identifiable celestial bodies, which may be obscured by weather or sunlight.

Astro navigation instruments have, in fact, used the sun, in addition to sensing stars in daylight. Military has had numerous astro navigation systems that worked day round: http://www.prc68.com/I/MD1.shtml

This may be interesting as well: http://gkaplan.us/content/NewTech.html

 

[CosmicGamer]

Space-based radio-positioning ala GPS is great, but is not the sole use, nor even the initial justification for satellites

If Space-based radio-positioning was not one of the initial justifications for satellites, what came before the Navy TRANSIT satellite system 1A in 1959? I thought just Sputnik 1?

 

[Vladika]

Bottom line, if you don't have celestial references and you lack the skill (or your computer is obnoxiously hard to use), then you're SOL. That doesn't sound like a problem so much as it sounds like an adventure scenario.

Adventure is just a romantic word for trouble? Try figuring out if you missed Bermuda after 3 days of storm and no visibility, double reefed, exhausted, cold and the whole crew suffering from varying degrees of seasickness. GPS at that moment is a God send. Sometimes its a fine line between SOL and an adventure scenario.

 

[Vladika]

:rofl: Come now, supertankers primary navigation method is visual? LMAO.

Never claimed it was, nor will I. You can't steer a ship worth a darn in storm conditions. Supertankers are underpowered and have large windage issues. Ask any sea-captain if he wants satellite GPS or an ocean full of towers during a storm. By the way, these wonderful towers are susceptible to storms and capsize and sink all to often. Ask their crews, but then you can't really do that in all to many cases. (I know, unnamed towers, but the point is they are vulnerable.)

Images for oil rig collisions: https://www.google.com/search?q=oil...uIoyN0QGbxYHYAg&ved=0CEYQsAQ&biw=1196&bih=598

Didn't the Exxon Valdez run aground on a clear day in site of land? Leaving a well traveled harbor that was a regular port of call?

Well, satellites are very expensive to build, launch, maintain (via earth based monitoring and adjustments) and replace. The HS-601, one of the most popular birds in the later '90's, generally cost $150-250 million just for the satellite.

How much does your average stationary deep ocean oil rig platform cost?

 

[Vladika]

For all of you "Let's abandon what works and go back to the past"

If airships and towers would actually work, and be cheaper, why are satellites the system in use?

Certainly, at this Tech level, we can build airships and build towers, at least in relatively shallow waters.

Maybe you could get jobs in government and effect a changeover? Or apply for a grant? Take out a patent?

I'm done though. Your educations, training and real world experiences far outstrip my degree and practice as a structural engineer.

 

[Timerover51]

:rofl: Come now, supertankers primary navigation method is visual? LMAO.
Man made structures, such as the over 500 oil rigs today, use RF for collision avoidance. A few thousand towers in something the size of the world's oceans is hardly going to pose a navigational hazard.

There was just a case of a 1,000 foot bulk cargo carrier in the Great Lakes hitting a bridge because they were reading from the rear radar rather than the front one, so they thought that they had a lot of clearance. The US Coast Guard was not exactly impressed that they did not have a visual lookout, who would have detected the collision possibilities.

Based on what we see in the Great Lakes, a few thousand ocean towers would be more than a minor navigational problem.

 

[BytePro]

Never claimed it was, nor will I. You can't steer a ship worth a darn in storm conditions. Supertankers are underpowered and have large windage issues. Ask any sea-captain if he wants satellite GPS or an ocean full of towers during a storm. By the way, these wonderful towers are susceptible to storms and capsize and sink all to often. Ask their crews, but then you can't really do that in all to many cases. (I know, unnamed towers, but the point is they are vulnerable.)

Underpowered and with windage issues that will put them hundreds of miles off course?

Satellites fail too... I know - worked with VSAT and HS-601 birds for several years. Also some familiarity with oil rigs. In neither case are the numbers significant nor a show stopper for either technology.

How much does your average stationary deep ocean oil rig platform cost?

Hows that relevant to the discussion on satellite cost vs airships?

 

[Timerover51]

If airships and towers would actually work, and be cheaper, why are satellites the system in use?

Certainly, at this Tech level, we can build airships and build towers, at least in relatively shallow waters.

Maybe you could get jobs in government and effect a changeover? Or apply for a grant? Take out a patent?

I'm done though. Your educations, training and real world experiences far outstrip my degree and practice as a structural engineer.

The problem is that no one is plugging the cost of such a system into the equation. Plug that in, and satellites become much more reasonable.

 

[Vladika]

Hows that relevant to the discussion on satellite cost vs airships?

Platforms were also under discussion. But , hey, you go fly the Hindenburg any ole time.

 

[Vladika]

Oil rig collisions

Oil rig collisions:

Images for oil rig collisions: https://www.google.com/search?q=oil...uIoyN0QGbxYHYAg&ved=0CEYQsAQ&biw=1196&bih=598
You don't need to be "hundreds of miles off course" when your towers are every 50 miles or so on a grid.

 

[BytePro]

If Space-based radio-positioning was not one of the initial justifications for satellites, what came before the Navy TRANSIT satellite system 1A in 1959?

Sputnik.

'Initial justifications' - sure, it later became a significant one (especially given the number of satellites required), but it was an observation of Sputnik that resulted in the idea that space-based navigation had merit. Initial justification were for surveillance. Though it proved the concept, the early TRANSIT system took half a decade or so to be used for navigation purposes - it served a surveying role and to update the inertia systems on submarines and was initially not useful for real-time position measurements due to the limitations of the system. The TRANSIT program later evolved into/was replaced by NavStar as far as I know.

 

[CosmicGamer]

If airships and towers would actually work, and be cheaper, why are satellites the system in use?

Because the U.S. Department of Defense (DOD) is responsible for GPS operations and management.

GPS was not made available for public use until 1983. The public encoding had much lower navigation resolution than the encrypted encoding used by the U.S. military.

In 1993 it was decided to provide access free of cost, all over the world.

Until 1996 the Selective Availability for civilian access was lifted giving civilian access the higher navigational resolution.

NOTE: The above is based on Google-Foo so don't hold me personally accountable for the accuracy.

 

[aramis]

Because the U.S. Department of Defense (DOD) is responsible for GPS operations and management.

GPS was not made available for public use until 1983. The public encoding had much lower navigation resolution than the encrypted encoding used by the U.S. military.

In 1993 it was decided to provide access free of cost, all over the world.

Until 1996 the Selective Availability for civilian access was lifted giving civilian access the higher navigational resolution.

NOTE: The above is based on Google-Foo so don't hold me personally accountable for the accuracy.

There was news footage of Army Corps of Engineers troops setting survey plates using a GPS, and moving in 5" or so increments... then shooting fixes with a theodolite off of it. Civil units are still only 3m or so... not the "half a foot" accuracy that I've repeatedly heard bandied about by drunk troops.

 

[BytePro]

Yeah - without the Cold War to justify the expense of satellites for spying and MAD the satellite industry today probably wouldn't exist. Without the Hindenburg disaster, airships might be in common use - even hauling cargo. If J. P. Morgan had funded Tesla, wireless power might be the norm and countries wouldn't be crisscrossed with power lines. If WWI hadn't resulted in the government purchasing batteries, and the automatic starter hadn't been invented, we'd probably all be driving electric cars and plastic would be a rare material...

If Turner hadn't been the exclusive satellite broadcaster at one point and a friend of a president, then Americans might all have fiber optics to their homes and Turner might not have any TV stations.

If Mickey Mouse didn't exist, then U.S. patent laws would likely not cover computer algorithms. Which means that superior compression technology would have continued advancing in the market, instead of being pulled (national security first right of refusal on patents).

Just because something is cheaper, or better doesn't mean anything as far as commercialism and what is produced and sold in the real world - and that's ignoring the reality of patents.

You don't need to be "hundreds of miles off course" when your towers are every 50 miles or so on a grid.

50 miles? Perhaps you are thinking cell phone towers - which are limited in range given cell phone and legal limits. It would take a lot more than a few thousand towers to cover the oceans in such a scenario.

As you seem interested in navigation - hyperbolic navigation systems, such as LORAN, could transmit well over a thousand miles (especially over ocean) and provided accuracies of well under a mile many decades ago. [Not sure about the more recent systems, like Omega, which I think used even lower frequencies and probably less accuracy, but larger range...]

The German Zeppelins navigated the North Sea during WWI using a pair of Telefunkin (sp?) towers. BTW, the Zeppelins (at least during WWII) carried several thousand pounds of bombs, IIRC.

 

[BytePro]

There was news footage of Army Corps of Engineers troops setting survey plates using a GPS, and moving in 5" or so increments... then shooting fixes with a theodolite off of it. Civil units are still only 3m or so... not the "half a foot" accuracy that I've repeatedly heard bandied about by drunk troops.

Yeah, there's a lot of anecdotal evidence that points to U.S. military accuracy in the inches range. Of course, there are different methods employable, even in the civil sector, that increase GPS based accuracy (hence probably the justification for dropping selective availability around the turn of the century). Differential GPS and land based augmenting claims go down into the single digit cm range!

I generally hear 10 foot for consumer devices, though FAA cites 40 feet or so, IIRC. The FAA is being conservative, of course, as GPS is influenced by varying timing though atmo, indirect readings, orbital and gravitational variations, etc. (mostly eliminated when a good many satellite signals are received).

 

[Vladika]

50 miles? Perhaps you are thinking cell phone towers - which are limited in range given cell phone and legal limits. It would take a lot more than a few thousand towers to cover the oceans in such a scenario.

Whatever you might think GPS is "line of site". Do away with satellites and you need thousands of towers. Kind of like FM, no matter the power of broadcast it is line of sight. AM can and does work on atmospheric "skip". You can't count on it for reliability or accuracy.

As you seem interested in navigation - hyperbolic navigation systems, such as LORAN, could transmit well over a thousand miles (especially over ocean) and provided accuracies of well under a mile many decades ago.

Look for and at old LORAN charts. They were an augmentation to accurate navigation. Mostly good to aid in dead reckoning situations. Small-craft captains, yacht, other pleasure and fishing boats wanted them kept due to common use of LORAN and expense of early GPS. No one at sea today would willingly give up GPS.

 

[Vladika]

There was news footage of Army Corps of Engineers troops setting survey plates using a GPS, and moving in 5" or so increments... then shooting fixes with a theodolite off of it. Civil units are still only 3m or so... not the "half a foot" accuracy that I've repeatedly heard bandied about by drunk troops.

Call any surveyor in your yellow pages and ask about their use of GPS today. Accuracy is stated to be within a cm. This is accepted for legal surveys and land boundaries and corners all over America. Good for recording of Deeds and obtaining Title Insurance.

Their systems are a lot better, and more expensive, the your car GPS.