Floating spaceport for future rockets

SpaceX’s early prototypes of Starship explode fairly regularly at the company’s Texas test facility, but the overall program is progressing at an alarming pace. The towering spacecraft, which CEO Elon Musk believes is key to building a sustainable human colony on Mars, has moved from CGI rendering to flying hardware in just a few years. This is fast in traditional rocket terminology, but there is little courage for anyone to call Starship traditional.

Almost all components of deep space vehicles are technological advances or deviations from standards. Its innovative full-flow multi-stage combustion engine is unprecedented in flight. It’s so complicated that other aerospace industries have given up I’m trying to build them decades ago. To support quick reusability, Starship’s smooth fuselage discards fine carbon fiber for its extremely hard (and heavy) stainless steel. A material that has not been used in rocket manufacturing since the dawn of the space age.

In addition, its size is very large. When mounted on top of the Starship’s corresponding super heavy booster, it will be taller and heavier than the iconic Saturn V and NASA’s upcoming space launch systems. At the booster lift-off, 31 Raptor engines generate incredible 16,000,000 pounds of thrust, unleashing horrific pressure waves that are literally deadly to anyone who gets too close to the ground.

This leads to an interesting question. Where can we safely launch (and land) such a giant rocket? Even in the ideal situation, you need to be a few kilometers away from the pad, but what if the worst happens? If a single-engine prototype burns, that’s one thing, but if a fully fueled starship stack explodes on a pad, the resulting fireball will have the energy equivalent to a few kilotons of TNT.

We may have an answer, thanks to the stream of consciousness that Elon frequently unloads on Twitter. Responding to comments on past efforts to launch orbital rockets from the ocean, Starship casually stated that once it began flying on a regular basis, it was likely to operate from a floating spaceport.

History warns us Excessive digging into Elon’s social media commentsThe potential benefits of launching a starship from the ocean are too few to be unruly dismissed. The Zenit rocket he refers to has successfully launched more than 30 orbits from its unique floating pad, especially because it is a proven technology.

The end of the Soviet rocket

Developed in the 1980s, the Zenit rocket replaces the aging Soyuz and Proton launchers that were the backbone of the Soviet space program. Although similar in size and specifications to the earlier versions of SpaceX’s Falcon 9, the Zenit, powered by liquid oxygen and refined kerosene, is cheaper and safer to operate than previous versions. Its ability to act as a strap booster for heavy vehicles, another similarity shared with Falcon 9, also promised to further streamline Soviet space logistics.

Zenit-2

Falcon 9 v1

Of course, that never happened. The Soviet Union collapsed and the program was left behind in politics before all bugs were resolved from the new booster. Not only is the Russian Federation lacking funding to get the most out of Soyuz, Proton and Zenit, but there are concerns about launching a newly independent rocket-sensitive payload manufactured in Ukraine. did. The Zenit program was almost completely canceled after some notable failures in the 1990s.

1 for land and 2 for sea

The dissolution of the Soviet Union eventually made Zenit unable to replace Soyuz and Proton, but it also offered some appetizing business potential. After the official end of the Cold War, a United Nations of companies from the United States, Russia, Ukraine and Norway was formed to provide Zenit to commercial customers. There is no need to determine the country that will act as a permanent base for the rocket, and the modified version of the vehicle will fly from a self-propelled ocean launch pad that began its life as an offshore oil rig. This revolutionary new service was properly called Sea Launch.

Beyond the political dimension of not being tied to any country, launching from the sea had many compelling advantages. For one thing, it was much safer for the rocket to explode on the pad or fail shortly after takeoff. This was especially important given Zenit’s somewhat uneven track record. It also allows launches from near the Earth’s equator, giving the vehicle greater tangential velocity during ascent, which directly leads to an increase in payload capacity.

The initial boost provided by the rotation of the Earth can be estimated by taking the speed of rotation of the planet at the equator and multiplying it by the cosine of the latitude of the launch point.

The gains gained from equatorial launch may seem small compared to orbital speed (approximately 28,000 km / h), but the rocket equation is not very tolerant. Much of the vehicle’s mass can be devoted to the payload rather than the propellant, even if the acceleration required to reach orbit is slightly reduced. In addition, payloads directed to the equatorial orbit, such as geostationary communications satellites, mean that they do not need to be tilted after being separated from the boosters. This further reduces propellant requirements and extends the useful life of the satellite as it enters final operational orbit sooner.

Shortening the experiment

Between 1999 and 2014, a total of 36 Zenit rockets were launched from Sea Launch’s floating pads, 32 of which put the payload into orbit. The most serious failure was in January 2007, when a rocket carrying the NSS-8 satellite failed within seconds of ignition, engulfing the launch pad in a fireball.

Due to the floating launch pad design, the rocket rocket fell through the opening of the platform and sank. It causes only superficial damage to the infrastructure you are riding. No one was on board as part of the normal operating procedure Ocean Odyssey Since it was the platform at the time of launch, no one was injured. The platform was repaired and ready for the next launch just six months after the accident.

From a technical point of view, Sea Launch has shown certain potential for orbital rockets launched from the ocean. Only a handful of failures the program experienced had nothing to do with the logistics of transporting rockets to the equator or the unique nature of floating launch pads. Even a single failure that got in Ocean Odyssey It is enough to delay the program for a very long time and rarely stops completely. If anything, the NSS-8 explosion demonstrated the inherent safety of a sea launch in the event of a catastrophic failure.

Unfortunately, Sea Launch was eventually killed by the same thing that made it possible in the first place: political turmoil. Russia’s annexation of Crimea in 2014 strained relations with Ukraine and Sea Launch officially denied that it had affected the situation, but within a few months staff were dismissed and Ocean Odyssey And its support vessel were bulletproof.

Rocket on the high seas

SpaceX has already won Considerable experience of landing a rocket on a floating platformUndoubtedly, it’s a more difficult feat than taking off from 1. The Sea Launch project has proved that there is no doubt that the concept works. You just need to scale up. As Elon pointed out, the Starship and Super Heavy boosters are much larger vehicles than the Zenit, but that doesn’t mean the core technology needs to be different.

The overall starship architecture is built on the concept of orbital refueling. In other words, each mission actually consists of multiple launches. For trips to Mars, up to 5 or 6 were all launched within a few days of each other.

Launches in the equatorial waters will help streamline this process as much as possible, allowing the maximum amount of propellant to be delivered to spacecraft waiting in orbit in the shortest amount of time. The profit per flight isn’t that great, but SpaceX is clearly playing a long game. At the very least, it will help keep such an operation incredible amounts of noise generated as far as possible from civilization.

Or, as we learned in SpaceX in the past, it may never happen. Perhaps the cost of building a fleet of huge floating spaceports will be high enough to negate the benefits of launching at sea. With all the changes the Starship design has made in just a few years, there’s little to be absolutely certain about this futuristic craft. Many suspected that it would never even be reached.

But even if SpaceX isn’t pushing to launch Starship from the ocean, there’s still hope for the concept of a rocket going to the ocean. Russian space agency Roscosmos has announced plans for them to suffer Ocean Odyssey Start again, This time only domestic technology is used. Like a stainless steel rocket, the sea launch pad seems to be returning to a new space racing style.