This has actually been done previously. The former Ocean Odyssey (https://en.wikipedia.org/wiki/Odyssey_(launch_platform) was used as a launch platform for a time after it was damaged by a blowout. (I had a very small part in the original drilling rig design.)
Semi-submersible rigs, of which this is an example, basically flood ballast tanks in lower pontoons to sink lower in the water for stability and then use typically 8 anchors to keep the rig in place. You can also use dynamic positioning although I think that was only used on drillships when I was involved.
Can you say a bit more about the anchors? I have in mind just large pieces of metal dragging on the ocean floor but I'm sure that's not representative.
Sure. I actually did a fair bit of work related to mooring system analysis.
Basically, the rig would be towed on station. Each of the four columns in the corners of the rig largely consisted of chain lockers and there were two big anchor windlasses at each corner. Each anchor would be lowered down in sequence and a work boat would carry the anchor out some distance with the chain playing out and drop it. It would then be tensioned using the windlass so that the anchor digs into the sea floor. This operation was then repeated. So you basically end up with a pair of anchors coming from each corner in some sort of a spread configuration.
I'm sure there were later designs that used dynamic positioning rather than anchors but those were just on drill ships when I was working.
They are designed to lodge and get partially buried in the sea floor soil.
Some oil rigs might be anchored more permanently to submerged concrete blocks or very heavy metal anchors, you basically drop them off a ship then when the rig moves into place you have divers connect the anchor cables to the previously submerged anchors.
Some also use steering engines for station keeping but that is usually for smaller exploration and mobile rigs.
>Some also use steering engines for station keeping but that is usually for smaller exploration and mobile rigs.
Yeah, I'm just familiar with exploration rigs. I was actually trying to remember if the Ocean Odyssey, which ended up being used by Sea Launch, for a launch platform, had dynamic positioning or not. I think it may have but I left before it launched and wasn't involved in that aspect of its design.
I think for sea launching dynamic positioning can be used the engines should be powerful enough and you have more control on under which sea conditions you’ll be operating under.
At that point the exhaust might be the biggest problem but if you design your exhaust deflectors correctly they themselves can be used for station keeping as long as you don’t vent everything from one side of the rig I think you’ll be all right.
Deep enough ballast tanks and dynamic positioning should be more than stable enough for launch.
I think the rigs in the med use dynamic positioning even on a semi permanent basis because the Mediterranean is much calmer compared to say the North Sea or even the Atlantic.
With drilling, your big constraint was stresses on the marine riser (the big pipe that connects the drill floor to the subsea blowout preventer) and the parts connected to it. As I recall you wanted to keep your horizontal deviation at less the 2-3% of water depth.
1. Get to the SpaceX terminal somewhere (maybe a major airport because of connecting flights), security checks, check in luggage and board an helicopter.
2. Fly to the launch platform.
3. Disembark, get up to Starship.
4. Many Gs of acceleration.
5. Fall to destination.
6. Many Gs of deceleration.
7. Disembark, board the helicopter.
8. Fly to the airport, immigration checks, collect luggage.
9. Leave the airport.
The two helicopter hops cost time, maybe not much more than some long rides on airport buses. The acceleration and deceleration will be exciting but maybe not everybody fit to fly can withstand them. I guess it's not for everybody.
I haven't been in the oil business for a long time but to get from a boat deck to the rig deck (actually the heliport in my experience) requires a transfer by a personnel basket which is apparently still used. https://www.grandoceanmarine.com/marine-safety-equipments/pe...
That's a bit different from a "modern airport experience." We would usually take helicopters out but if weather didn't cooperate (or the oil company we were working for didn't want to pay for it), we would sometimes take work boats.
Added: I assume though if someone wanted to do so, they could design an enclosed capsule of some sort that people could sit in and that capsule could be lifted with a crane which would be a bit less "exciting."
The general public is going to get something looks like elevators, even if their all just baskets suspended from a wire. Honestly saving ~17 hours NYC to Auckland is going to be worth some inconvenience. However, a bigger issue is how calm the weather needs to be before their going to launch rockets, though that means people aren’t going to go out to the launch platform in bad weather.
Boat to boat transfers are tricky. I'd still put my money on some sort of lift. Though TBH if we're stipulating a level of science fiction that allows routine human suborbital flight, getting people out to a launch platform comfortably and safely is not a hard problem by comparison.
>However, a bigger issue is how calm the weather needs to be before their going to launch rockets, though that means people aren’t going to go out to the launch platform in bad weather.
I'm honestly not sure why you wouldn't just use helicopters. They're not that unsafe if flown in good weather. VIPs fly in them all the time.
Most cities have regulations around helicopters which may cause issues. I think the boat concept is based around moving people from the city center rather than speed after pickup.
Really, a 40+ MPH boat ride gets you to a launch site 8 miles out to sea in around 5 minutes which is both safer and good enough to not really benefit from using a helicopter.
The point still stands. If you're handling a thousand passengers per day, you will obviously have more efficient transfers options than if you're operating an oil rig doing occasional personnel transfers. It's not a serious objection.
For a passenger port though they'll probably come up with something different. Not sure if there's anything preventing a fairly normal dock from being added to the rig at water level with an elevator to take people to the main levels along on of the legs.
Most rigs don't receive large amounts of visitors either so the high cost and low volume of helicopter rides makes sense. A rig working as a rocket port needs to move more people through it so the economics of figuring out a dock makes more sense.
Also they have the tech with actively stabilized gangplanks to make the link between the more stable rig and the docks.
Small children, babies, 85 year olds, disabled people all fly and probably make much more of the passenger population than you think. Also with the levels of obesity in many countries and other conditions I’m not sure how many “healthy adults” over the age of 30-35 you’ll find that could handle 3G without any risk.
I think the start ship on earth concept is a pipe dream, I give hyperloop a better chance of succeeding.
Those gangways look nice. They could make them look like normal jet bridges with the nice side effect of not scaring people with the fear of falling into the sea, etc.
About accelerations, many people scream when they are in a car braking or turning at some low 0.x G, so I wonder what a couple of Gs would be to them. Anyway, there will always be plenty of planes and they'll be much cheaper too.
> Those gangways look nice. They could make them look like normal jet bridges
Nod. And given the difference in duty cycle from supply ships and oil rigs, they might be mounted on the rig rather than the boat. Removing the "it has to fit folded up on the ship" constraint. And with luggage perhaps containerized onboard the ship, the containers would need to be transferred too.
Hydrofoils are sort of seaplanes? They just keep the wing in the water. And so don't have to deal with being not-so-great airplanes, so they can focus on being good boats.
Starship might end up even more robust to weather than airliners. As are boats. But seaplanes combine the vulnerability of planes, with the those of poor boats. Taking off in a swell, is not a happy thing. I suppose SpX could hypothetically do JATO rocket-assisted seaplanes. :P
But consider the number of passengers. And choices of flying formations of existing seaplanes for each launch, or "let's create a brand new large airliner, and make it a seaplane too!" (even without the seaplane bit, those can be 'bet the aerospace company' gambles), or... order some ferries. Maybe even rent them to start.
I wonder by how many orders of magnitude that this would be less safe and more expensive that as commercial airline first class ticket to the same destination.
Those two helicopter hops probably make the trip 100x more dangerous by them selves.
They're not gonna be trying to land rockets in bad weather so the helicopter rides should pretty much all take place during ideal conditions. Point to point helicopter rides are also very safe relatively speaking. Industrial and emergency helicopter usage really drags down the average.
>Point to point helicopter rides are also very safe relatively speaking
Not for coastal ops. It falls in the more dangerous category.
All rig workers are required to pass HUET- Helicopter Underwater Egress Training.
The gyro forces of the rotating blades ensure any splashdown is followed immediately by the helicopter inverting itself- so underwater and upside down. It also involves the immediate need for survival swimming, with a presumption of a burning oil slick at the surface that must be splashed clear each time you surface, until you can clear the wreckage.
And since the water might be dirty, or covered in oil slick or debris, this training is often done blindfolded.
It's not a rule (that I know of), but it's a standard part of the more serious training classes. The companies I'm familiar with have been teaching it that way for 15+ years. Edited to "often"
Also an engineer, but was first required to do it way back as a summer intern working on a deepwater support ship. A helicopter ride for me at the time would have only been for an emergency, but it was still required training.
I'm sure safety standards went up over time. For example, after the Ocean Ranger went down off Newfoundland, survival suits became standard (which they amazingly hadn't been previously even in cold weather operations).
Can you honestly not see the difference between a taxi that will only be used on days clear enough to land a rocket and regular ship to shore operations characteristic of the oil industry?
Tesla's use case is likely less dangerous than the helicopters that fly VIPs all around NYC simply because the airspace will be so much less cluttered allowing for higher faster flights that are more tolerant of things going wrong.
If you see a significant difference, it's only because you want to see one.
The Gulf of Mexico already has the highest amount of helicopter traffic in the country. It's always cluttered. I'd expect most of the local helicopter services and pilots that ferry the oil industry would be also be ferrying for SpaceX.
>Tesla's use case
The SpaceX use case is based on high frequency launches. You don't get high frequency by sticking to Space Shuttle blue-sky launch requirements. (And the safety-obsessed oil industry isn't flying in weather it shouldn't be.)
But it's still coastal weather, and even blue-sky launches are going to require pre-dawn (or after dark), foggy and/or windy flights out to the rig (and back to shore).
If it's point-to-point rocket travel, daylight at the launch site means it's likely to be dark at landing, and vice-versa. Otherwise flight windows are going to be very restricted.
If anything, time windows are likely to be more constrained for launches than for the oil industry (who might have a day-long+ window for personnel changes), which means more flying when you have to, not waiting for when conditions are ideal.
> how many orders of magnitude [...] more expensive [...] commercial airline first class ticket
Estimates are order zero. Amortization on more frequent (because quicker) flights. Rocket vs airliner simplicity. Fuel is only a fraction of airline opex.
By the time it's open to the public, I'd expect for it to be approximately as safe as air travel currently is, possibly even more safe, given the very reasonable apprehension the public will have to rocket travel.
And I'd expect the US Government to be heavily involved in ensuring that to be the case.
Musk has mentioned using Hyperloop to transport people to the launch platforms. I don't have time to dig up the interview I heard it in but I'm pretty sure he said as much at one point.
It’s worth noting that Musk quoted 30-60 minutes rocket trip time for any pair of source/destination in the world, so there is a lot of room for time wasted around the launch while still being way faster.
That said, they probably have to run hundreds of thousands or millions of non-crewed launches before they can demonstrate it’s safe enough for civilian use. Current tech must be in the range of 3-4 orders of magnitude more dangerous?
Sounds like a nightmare.
One key aspect is also the weather. Flying will only be possible under perfect weather conditions for both take off and landing.
Will the passengers require a class-3 flight physical? High-G's can be risky to some people. blood pressure, risk of stroke, etc... Examples would be the number of medical issues that arise at roller coasters and the related posted warnings on them.
I am almost certain that, at a certain point, the US military will use Starship to deploy some extra forces (specialists and equipment) to a distant theater of operations under a tight schedule. Or perhaps evacuate the sick and the wounded, if they can tolerate this rough ride but need to see a top hospital urgently. So as far as humans go, that will probably happen.
A regular service for civilian customers, that is another story. Just like Concorde, it might prove economically infeasible.
Will starship land with enough fuel to take off and return to friendly territory?
Can starship land in Earth like gravity on a standard concrete area?
Concorde's heels were
1) No supersonic over water
2) Limited Range
3) Limited use to reclaim development costs and ongoing maintenence costs
4) Eating into their owners fares -- standard London-NY cost was £8k return, or £13k today. That's in the same ballpark as an F return pre-covid, so BA weren't making more money.
> Will starship land with enough fuel to take off and return to friendly territory?
No. If you want it back, you land at a friendly base. The nominal use would not likely to be for insertion but logistics, like a really fast C-17.
It's intended to be quite cheap to build, however, so it's not impossible that it could be used one way (in a very high-value operation.)
> Can starship land in Earth like gravity on a standard concrete area?
Yes. They're doing that right now. Taking off from a flat pad, however, is unlikely, at least in current configuration. A "tactical" version with pre-main-ignition "hop" engines, like planned for the lunar lander version, might allow such ops (providing you can provide large quantities of liquid methane and oxygen on site!)
Not many nimbys if you're 20 miles off the coast of NY going to 20 mile off the Singapore coast (not that nimbys would have any say in Singapore), and nobody en-route would even know it's flying overhead.
OK you have a 30 minute ride at each end from downtown, but that's not much more than going to JFK/Changi from downtown. 1 hour checkin and 1 hour flight, you're doing end to end in 3 hours rather than 22.
Many Gs of acceleration: I don't think it would be a huge problem, when lying on your back, in a g-suit or submerged in water. I don't think it would require liquid breathing, which is not fully developed yet.
Many Gs of deceleration: for the passenger, acceleration and deceleration have the same effects.
1) Get into a rocket, lift-off, land on the platform.
2) Play with a complimentary Space Grenade Launcher™ on the rim of the platform while you wait for refuel.
3) Go to space for some time
4) Land in your destination platform
5) Summon your Tesla over the under-the-ocean tunnel
6) Go home.
Typically people flying on a helicopter to an oil rig need to be trained to ditch in the water. I think most would consider that prohibitive for the Starship transit clientele, so I wonder if they just live with the risks.
I don't think they're as different in energy as you're thinking. "Suborbital" ranges from throwing a baseball 100ft to going almost into orbit, and going halfway around the earth is just shy of a circular orbit. It would be different if you were doing a short hop, but Starship is impractical for short hops.
Don't forget all the vomit. Put ten passengers in a single space, even trained astronauts, and at least one of them will be vomiting during the zero-G portion of the flight. Compare this to a first class seat on a BA transatlantic crossing.
(And the carbon costs of rocket-powered passenger services are maddening. This is not a service that anyone should support.)
Starship is methane-powered. There are ways to generate methane sustainably (from C02 and water); that's even an essential part of the plan for Mars. I strongly suspect they'll want to test it on Earth before, and having an appliance on the platform that generates the needed propellant for passenger flight would be a very good test (developing something that works reliably with minimal / no human intervention).
> Starship is methane-powered. There are ways to generate methane sustainably (from C02 and water);
It's not about the generation. Burning methane results in a 1:1 emission of CO2 [0]; literally the equivalent of just dumping pure carbon dioxide into the atmosphere.
That doesn't matter if you made the methane by extracting CO2 from the atmosphere. Then you are just putting the CO2 back from where you got it.
The bad part with burning fossil fuels is that you are putting carbon in the form of CO2 into the air which was previously locked under ground in the form of coal/gas/oil. If you are burning carbon that you extracted from CO2 in the atmosphere, there is no such problem, assuming you didn't use fossil fuels to extract that carbon.
>That doesn't matter if you made the methane by extracting CO2 from the atmosphere. Then you are just putting the CO2 back from where you got it.
It's not that simple. What you're describing is free energy. We're still burning fossil fuels to extract the methane. Maybe that could be powered by renewables one day. But as of now, it is not.
The point is you could do it with renewables without burning fossil fuels. There would be losses in the step between renewables and methane sure, but it doesn't require "free energy".
Ya, but that isn't happening. Look at where liquid hydrogen for rockets is sourced. It could be made from water. In reality, it is made from hydrocarbons because that is cheaper. And even if CO2 is pulled from the air, a huge amount of energy is need to compress/store that rocket fuel, energy that could be put to far better uses. Instead of launching a passenger rocket to london, I'd rather divert that energy into shutting a coal-fired powerplant for a week or two. Once all those powerplants are shut, then we should look at passenger rocket services.
I don't doubt you're right for most existing rockets, but I think the main difference here is that SpaceX has every reason to test the hell out of their propellant-producing appliances here on Earth, even if it's not economical at the beginning. They depend on these appliances working perfectly on Mars for the return trip, so they need to be _very_ reliable.
If these vehicles were from anyone besides a company whose explicit goal is to develop an interplanetary colony ship whose duty cycle will require the launch infrastructure on the other planet to convert atmospheric CO2 into methane using solar power, I’d agree — it hasn’t been done, it’s not economical to do it that way yet.
But Musk needs this process to become economical so that Mars can become economical.
(The same tech may, ironically given Tesla, compete with batteries for the energy storage PV calls for).
The fuels in the rocket. The fuels in the support vehicles. The fuels for the platform. The fuels in the helicopters. Even if all of them are produced from solar power, a 747 needs less than 1% of the same total fuel per passenger. No matter how it is fueled, a ballistic rocket needs orders of magnitude more energy than conventional flight. It is not an energy-efficient means of realworld transport.
Do you have any numbers to back that up? A 747 burns 10-11 tons of fuel per hour and carries about 360 passengers. For a 12 hour flight, that is about 350kg of fuel per passenger. Starship's tanks hold approximately 250 tons of fuel and 950 tons of liquid oxygen. In order to match the per passenger fuel efficiency of a 747 they would need to carry about 700 passengers. Starship has about 20% more internal volume as a 747, so it seems likely that they would be able to fit at least the same number of passengers. That puts them at about 50% of the fuel efficiency of a 747.
In addition, methane combustion produces 2.75kg of CO2 per kg of fuel, while kerosene produces 3kg CO2 per kg of fuel. If they are able to fit 20% more passengers than a 747 due to the larger internal volume then they would be within about 66% efficiency on a CO2 emissions per passenger basis.
As I replied to others, rocket fuel is very different. The total carbon emissions include not just the fuel used by the rocket but the fuels used to create those fuels before the flight. Liquid oxygen is not carbon-free as creating liquid oxygen requires lots and lots of energy. So too methane which is heavily refined/compressed/cooled, processes that take more energy, create more emissions, than burning the fuel itself during flight. The fuel for a 747 is not nearly as energy/carbon-intensive to create.
Not sure where you're getting these figures. Here's an analysis which estimates CO2 emissions from Starship for E2E will be roughly similar to those from a 777 flight based on fuel consumption. Depending upon how the methane is generated it could be a carbon-neutral flight. This doesn't include support vehicles, but that would be quite speculative at this stage.
Look deeper at those numbers. Net fuel consumption/emissions is different than "rocket emissions". Rocket fuel isn't diesel. The emissions from the actual rocket in flight do not capture the total emissions generated in the creation/preparation/compression of rocket fuels. Some rockets produce literally zero carbon during flight (liquid hydrogen + liquid oxygen = water) but that doesn't mean plenty of coal/oil wasn't used in the creation of those fuels.
Yep - pushing air away for 12+ hours at high sub sonic speeds might indeed be less efficient than a sub orbital flight where you exit the atmosphere in a couple minutes and cover most of the distance without meaningful air resistance in the vacuum of space.
Lol, I'm no communist but I do appreciate that market forces alone will never address the carbon/energy problem, let alone the wider problem of pollution overall. Just because someone has the money do to so doesn't mean that we should support them burning away the energy to light a small city simply to get to their vacation spot a few hours faster than on a private jet.
How about reaching a dying father a few hours faster? A middle class person might judge the extra $5-10k (from savings) worth it.
If SpaceX/energy company deploys a new nuclear power plant (and one day fusion) to provide the energy, why should you care? It's a new energy source and not competing away your personal idea of worthwhile energy use.
Oil rigs are super fascinating from an engineering perspective. Ironically, outside of space the ocean is probably the most inhospitable environment for man-made structures to be built where we still want them. Anybody wanting to build platforms/cities/anything else in the ocean would probably do well to start by looking oil rig construction.
That's an interesting point. The article says that the rigs were bought for $3.5 million each. At that price, it seems pretty obtainable for people interested in creating a floating city at sea to buy a few as a starting point.
Absolutely back when I worked in Hydrodynamics RnD we built a test rig that could simulate some aspects of that - 21 Cumecs flow rate! (fist time we turned it on its set the alarms of on Cranfield Universities Power supply)
Heck yeah they do. For anyone else interested who hasn’t seen it, check out “types” in the wiki article linked above for a nice picture of some variations in common use. Fun stuff to compute the wave induced motions of... The math is very similar to a circuit analysis (linear time invariant systems). But the properties of your “circuit” (your boat, craft, platform, whatever) are solved by hydrodynamics to account for the shape dependence, environment dependence, etc. and depending what you want to know - done in the time domain or frequency domain as well.
I would love to see the modeling they must be doing to make sure that the floating rig is stable while 11mil lbs of rocket with 15mil lbs of thrust launches.
Rockets have very high mass ratios. A fully fueled rocket is by mass almost all propellant. This is counterintuitive, other vehicles do not have that. Rockets also have very high thrust to weight ratios.
One of the effects is that flying an almost-empty rocket is really easy. When landing, the Falcon 9 first stage actually has too much thrust to even hover stably with one ninth of engines running and that at only partial thrust.
So an empty rocket flying doesn't produce nearly as much noise or pressure waves. So, you could do it like this:
1. The light, almost unfueled rocket stands at airfield
2. People board the light rocket
3. The light rocket flies a short hop to an oil rig (20 km or so). Only one rocket engine needed for takeoff and landing.
4. The light almost empty rocket is fully fueled at the oil rig. It becomes a heavy fully fueled rocket. People stay inside.
5. Heavy fully fueled rocket takes off with all engines blasting with massive noise.
6. Most propellant is expended during acceleration. Heavy fully fueled rocket becomes light almost empty rocket.
7. The light almost empty rocket lands at destination airport with one engine.
The advantages are that you don't need to offboard and onboard, and you don't need personnel facilities at the refueling stop.
Also fueling doesn't need to take an hour. The rocket consumes its fuel in minutes, fueling could be as fast.
The fuel pumps are literally powered by the rocket and use high pressure tanks to prevent vacuums from forming in the tanks. How do you plan on achieving that on the pad?
It's just engineering. It's much easier than the turbopumps on the rocket. The rocket pumps have a much harder job than these refueling pumps, since the rocket's pumps have to raise the pressure to higher than the engine chamber pressure, so in Raptor that would be about three hundred bars (4500 psi). No such issue in tanking as the rocket tank pressure is low.
You can also just use electrical pumps with no weight or size constraints, since it's not flight hardware. Large scale LNG pumping solutions at least are off the shelf items for LNG tanker ships.
There also exist solutions for what to do with the gases in the LNG tank when it's filled. Oxygen tank contents you can of course just vent to the atmosphere.
Falcon 9 first stage flight lasts 2 minutes and 34 seconds.
Tanks go from full to empty. [1] You could design the refueling operation to be ten minutes if it provided some benefit to you.
Yeah I’m sure it is solvable. It just doesn’t seem like the kind of thing worth doing. But if you told me 5 years ago a first stage booster could land and be reused I’d have laughed in your face.
So yeah, maybe!
Would be pretty funny if SpaceX could refuel a Starship faster than Tesla can recharge a Model S!
Seems more practical to use conventional transport to go to and from the rig, such as a helicopter.
A crash with a rocket is both more likely and more devastating, and thus should happen away from population centers. Even if the return trip is less noisy.
Also rockets pollute, which is another reason to keep them far away from people.
The last point you make is only partially true. The Starship is using Methane and Oxygen and produces mostly CO2 and Water as output. Since they plan to produce propellant using the Sabatier process using renewable energy you get a nearly closed cycle. There's a fantastic video by EverydayAstronaut on Youtube about this topic.
The coolest part? They will scale it up to have hundreads of platforms, clustered fairly close likely, so they'll be able to continuously launch 1,000 Starships as Elon's stated goal.
No problem, couldn't care less about the downvotes. Yes, it is an impressive thing to imagine. But the scale you are talking about is not something that I expect to see in a very long time, if ever. The degree of international cooperation that would require just isn't on the books in the present climate, and Musk has a habit of throwing grand visions with unspecified or wildly optimistic time-tables out there.
He's our generation's Howard Hughes, genius but flawed. That doesn't mean he isn't moving the needle forward in a very meaningful way but at the same time I don't believe every word he says.
Naw, the moment SpaceX starts capturing astroids or mining on Mars there's a whole new world, literally, worth of economic value unlocked. There are other defensive strategic reasons to have many launch pads as well. They're creating a manufacturing line for Starships to be able to "mass" produce them. Elon gets exponentials, and he'll build whatever technology or follow whatever strategy he figures out that's needed to make what he's doing self-sustaining. There's plenty of opportunity to tap and revenue streams, profits, he can direct towards SpaceX if needed.
Eh, the Starship rocket doesn't really make smog itself. High levels of liquid nitrogen may if it interacts with organics from sea spray.
With all that said, oceans tend to be pretty windy around 90% of the time so things that cause air to be still on land are much more rare in most parts of the ocean.
Launch is going to be one of the most inefficient parts of the burn, both due to the required impulse and also due to the thermal state change of the engines. I wouldn't be so quick to hand-wave this away.
Maybe they will have to space them out a fair amount then to help reduce that, allowing the area current to
Hell, maybe they can build a catch system surrounding the launch pad and vacuum in to capture the pollution. You just need big or many motors - probably could use Tesla's motors?
Maybe what they can capture at the level of the landing pad is moot though...
Wow, acquiring a semi-submersible drilling rig (in use for 12 years it seems, came into service 2008) for $3.5 million? It cost $312 dollars to build. I get there are a lot of environmental concerns with these kinds of things but this just seems like a steal.
The market for off-shore oil drilling has collapsed, as it can't currently compete with on-shore (e.g., shale). So most of them are now only worth their scrap value, which isn't trivial but from which you also need to subtract scrapping cost. It's not surprising to me that a $300M piece of machinery has <$10M of metal scrap value, and you loose half in the scrapping process. Your $30,000 dollar car is only worth about $200 as scrap.
From article: "The super heavy lift launch vehicle will have a large blast danger area and pose noise concerns if launched frequently near populated areas."
Why a sea platform vs a remote area? It can't be that hard to find a few remote areas and significantly cheaper being on land?
Any other reason to do this? Ability to move? Stay within range of key cities where remote areas are harder to find?
>It can't be that hard to find a few remote areas and significantly cheaper being on land?
The shore along the oceans tend to be the most populated areas on the planet. Unless of course they have some terrible geographical issue like being a bottomless swamp or unscalable mountain.
In addition you want to generally launch to the east to get a boost with the earths rotation. In the US the east coast is generally flat and mostly easy to build on, which means a ton of people live along it.
The US doesn't fly rockets over land due to population - I'm sure this is probably law, but I don't know specifically. It's also easier to clear launch zones in water vs land, as vessels have maritime transponders (not sure of law or terminology here). Your last point is probably the most important - being close to cities but far enough away to not bother folks is the dance.
Where they're launching now is fairly remote, and they bought out anyone who lived nearby.
I wonder if it's really about that. Presumably if you could launch at the equator it would be a little cheaper to get to space, but having floating platforms that far away might eat up those benefits and more.
I think it is really the number and frequency of orbital launches required for refueling that is the concern right now. SpaceX would love to get approval for unlimited orbital flights from Boca Chica, but it is four miles away from South Padre Island and it would probably require a massive deluge system and huge water storage to get approval for that. The can also launch from Kennedy, but they are trying to keep all three options on the table for now.
The reality is that they bought the platforms for cheap, but haven't made any renovations yet so for now it may just be a backup plan.
The same reason they currently land Falcon 9's on ocean platforms: because rocket trajectories are almost always required to go over water for safety reasons. The only time they use land landings is when there is sufficient excess fuel to return to the launch site (which is along the shore).
you need a HUGE area of exclusion incase if explosion, and it need to have a large down range uninhabited area (ocean or desert). it is actually very difficult to find a large coastal land area uninhabited, or large inland area that is uninhabited for hundreds of miles down range.
When it goes boom, they won't have to clean it up, that is all done automatically for them. And vanity of course - "sea launch master race vs peasant land launches."
More importantly, if it goes boom the pieces dont fall on anyone. There's a big difference in area between a launch site and the down range keep-out area.
They also plan to catch the first stage using the launch tower instead of landing them on the platform. There's some fan-art around, but I can't wait to see some SpaceX originated concept designs of this.
Anyone has an input on how the salt of the water could impact the rockets on reusability ? I've been wondering since they catch the rockets in the ocean
Starship will use 304L stainless steel due to it's good performance at cryogenic temps. 304L just so happens to be the best kind of stainless steel for salt water exposure.
Not sure if any other steps will need to be taken for greater protection (for the ceramic heat shielding etc).
Yes, but you need to get them there, even then it's going to be negative money so owners would want subsidies. So for example, as the North Sea fields die, the Cromarty Firth in North East Scotland is getting rigs at an increasing pace, they just mothball them in the firth in the hope they can get a refit or sell them, but they rarely seem to be able to do either these days (there's a set of jack up legs that have been there for at least 15 years for example). Nobody's buying them for scrap and paying to drag them halfway across the world any more (there was a suggestion money was going to get pumped into a breaking yard down the coast in England, at Middlesbrough, but looks like wasn't financially viable). Financial incentives aren't there, so it's easier to just find a coastal location to moor them that's cheap, where they rot. There's no cash value in them, it's usage that makes money and that ain't happening a lot now, the owners of the ones Musk's bought will have bitten his hand off.
Edit: for clarity, it's a massive financial bet building a platform -- they have specific purposes and take a long time to plan and build, but the deployment environment (physical/political/economic) is volatile relative the build timespan. That doesn't matter in boomtime, any hits are absorbable, but it is not boomtime. The above Scottish example, a fair % of the rigs in the firth at any one time are "new" (as in unused). They get kept in hopes of refits, not scrapped; it's too expensive to scrap.
i would imagine they're very polluted. it's surprising the price isn't negative, in that someone pays you to take ownership because the EPA is forcing a clean up.
They're a liability, you can buy them at a fraction of the their original value but to unload them you have to find a sucker who will be on the hook for the eventual cleanup.
iirc, they use a large sound barrier around the blast area in the ocean. the 'fence' is a giant fence of bubbles rising to the top, and the bubbles act as a sonic barrier.
Not sure why you were downvoted - given how well sound travels in a medium like sea-water, and given how incredibly loud rockets are it's going to make life hell for sealife within a very large radius/volume.
I'm a huge fan of what SpaceX is doing, but to simply ignore environmental impact here would be quite blinkered.
Semi-submersible rigs, of which this is an example, basically flood ballast tanks in lower pontoons to sink lower in the water for stability and then use typically 8 anchors to keep the rig in place. You can also use dynamic positioning although I think that was only used on drillships when I was involved.