This has actually been done previously. The former Ocean Odyssey (<a href="https://en.wikipedia.org/wiki/Odyssey_(launch_platform)" rel="nofollow">https://en.wikipedia.org/wiki/Odyssey_(launch_platform)</a> 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.)<p>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.
The passenger experience would be:<p>1. Get to the SpaceX terminal somewhere (maybe a major airport because of connecting flights), security checks, check in luggage and board an helicopter.<p>2. Fly to the launch platform.<p>3. Disembark, get up to Starship.<p>4. Many Gs of acceleration.<p>5. Fall to destination.<p>6. Many Gs of deceleration.<p>7. Disembark, board the helicopter.<p>8. Fly to the airport, immigration checks, collect luggage.<p>9. Leave the airport.<p>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.
Didn’t realize oil rigs float. Some do. Found this WP even more interesting than the OP.<p><a href="https://en.m.wikipedia.org/wiki/Oil_platform" rel="nofollow">https://en.m.wikipedia.org/wiki/Oil_platform</a>
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.<p>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.<p>So an empty rocket flying doesn't produce nearly as much noise or pressure waves. So, you could do it like this:<p>1. The light, almost unfueled rocket stands at airfield<p>2. People board the light rocket<p>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.<p>4. The light almost empty rocket is fully fueled at the oil rig. It becomes a heavy fully fueled rocket. People stay inside.<p>5. Heavy fully fueled rocket takes off with all engines blasting with massive noise.<p>6. Most propellant is expended during acceleration. Heavy fully fueled rocket becomes light almost empty rocket.<p>7. The light almost empty rocket lands at destination airport with one engine.<p>8. People offboard<p>9. Goto 1.
Here's a video (not by SpaceX) showing what these spaceports may look like one day<p><a href="https://www.youtube.com/watch?v=VtAC6s4PYj8" rel="nofollow">https://www.youtube.com/watch?v=VtAC6s4PYj8</a> "SpaceX Starship sea launch concept" by SpaceXvision<p>There's also an official video by SpaceX showing a sea platform at 0:25minutes: <a href="https://www.youtube.com/watch?v=zqE-ultsWt0" rel="nofollow">https://www.youtube.com/watch?v=zqE-ultsWt0</a>
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.
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."<p>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?<p>Any other reason to do this? Ability to move? Stay within range of key cities where remote areas are harder to find?
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
Reminds me of Sea-Launch <a href="https://en.wikipedia.org/wiki/Sea_Launch" rel="nofollow">https://en.wikipedia.org/wiki/Sea_Launch</a>
Makes me wonder if he ever thinks about <a href="https://en.wikipedia.org/wiki/Sea_Dragon_(rocket)" rel="nofollow">https://en.wikipedia.org/wiki/Sea_Dragon_(rocket)</a>?