It’s no secret that SpaceX has revolutionized the world of space travel, with the company’s founder Elon Musk becoming more popular than ever in recent years. Now, SpaceX is revealing plans to change the game yet again with entirely new fuel. Why? What does this mean for space travel, and why should you care? Let’s take a look!
Why reusable rockets are important
Due to their enormous size, rockets are often viewed as disposable. This idea makes sense when you think about manufacturing costs: making reusable rockets out of strong yet lightweight materials is more expensive than just building them out of lightweight but weak materials. But since SpaceX’s ultimate goal is to make space travel cheap enough that we can live in outer space full-time—and since they’re currently experimenting with sustainable aviation fuel—it makes sense for them to rethink how we build our craft. (Read How Rockets Work for more info.) By finding ways to make our vehicles reusable, we can use fewer resources in transportation.
Most rockets are made from aluminium alloys; we usually use aluminium because of its high strength-to-weight ratio—meaning that you can build structures out of it that are both strong and light. But while aluminium is lighter than other metals like steel or titanium, its melting point isn’t as high. This means that when your rocket returns to Earth after being in space for a while, it has to slow down quickly before burning up on re-entry—which means putting intense heat onto any material used on the exterior of your rocket.
To combat that issue, reusable rockets usually rely on passive cooling systems. For example, aerodynamic fins can be used to slow down your vehicle upon reentry. Since they’re lightweight and simple to make, they don’t add much weight to your craft—making them an ideal choice for keeping your rocket light in space. But what if we didn’t have to return to Earth? Well, we wouldn’t need special materials on our rockets—and aluminium alloys wouldn’t be nearly as cost-effective as others like titanium or steel.
What technology allows reusable rockets to happen
For many years, rockets have been expendable. That means that every time you launch a rocket for commercial or military purposes, you’re blowing up an extremely expensive piece of equipment. And that’s not really viable long-term for anyone but governments (or those with deep pockets). So what if rockets could be reused? Theoretically, that would lower the cost of spaceflight—which would make going to space easier and more affordable. But how does one make that happen?
Well, that’s where SpaceX comes in. They’ve developed what they call Grasshopper, which uses methane as its fuel source. This allows them to refuel their reusable rockets in midair—which makes them much cheaper than traditional ones. There are still plenty of challenges ahead for SpaceX before reusable rockets become mainstream technology—but we’re getting closer all the time!
In other words, they’re doing what aviation has done for decades. Traditional aviation uses hydrocarbon-based fuels because they’re efficient (though not without their problems). While there are other types of fuels that could be used—such as hydrogen—hydrocarbons are easy to store and very reliable. But that means their emissions can be harmful if we don’t do something about them. So companies like SpaceX—as well as government agencies like NASA—are trying to develop better sustainable aviation fuels. This is where methane comes in: it’s got an energy density similar to hydrocarbons but with fewer carbon emissions. Of course, methane can also explode (just ask Mark Watney) so safety testing will still need to occur before we start filling up our cars with methane.
How reusability will impact rocket technology in the future
Since April 2010, SpaceX has been upgrading its Falcon 9 rocket for reusability. The company has recovered two of its rockets after launch—the first in December 2015 following a cargo resupply mission to deliver supplies to astronauts living at the International Space Station; and a Falcon 9 Full Thrust first stage booster on May 6th that was used in another resupply mission. Both rockets are now ready for future missions as part of ongoing efforts to commercialize spaceflight by making access more affordable. But there’s one question that remains: What’s next? To figure out what lies ahead, let’s take a closer look at methane fuels—what they are and how they work.
What are methane fuels? Methane has been used as rocket fuel for decades, dating back to the German V-2 rockets of World War II. When burned with liquid oxygen—in which case it’s referred to as methane liquid oxygen or metal ox—it produces exhaust that includes nitrogen gas and water vapour. These gases do not produce particulate matter pollution during combustion, so they don’t harm Earth’s atmosphere. Thus far, most rockets that use methane propellant have relied on traditional chemical propulsion technology.
How do methane fuels work? When methane burns in liquid oxygen—again, producing nitrogen gas and water vapour—the resulting propellant produces far more thrust than other traditional solid or liquid propellants. The reason for that is that nitrogen gas has an extremely low molecular weight compared to other rocket propellants like hydrazine or hydrogen peroxide. This means that methane’s combustion reaction creates far more energy than other popular forms of chemical propulsion such as kerosene (RP-1) and hydrogen.
The potential of reusability
The Falcon 9 uses liquid oxygen and rocket-grade kerosene (RP-1) as propellants. The rocket’s first stage also uses liquid oxygen. However, while RP-1 has been used as a fuel in most of SpaceX’s launches to date, they are also experimenting with methane. If they can master its use in their rockets (which are significantly more powerful than those that burn RP-1), it could mean huge savings for them. Liquid oxygen must be stored at extremely low temperatures (-340°F/-210°C), which makes transporting it around very expensive. Using methane instead would eliminate these costs entirely – enabling them to deliver on Elon Musk’s long-term goal of reusable rockets.
This potential breakthrough has been made possible by another technology that SpaceX has pioneered: supercooled propellants. By storing propellants at their extremely low liquid-oxygen temperatures (-340°F/-210°C), but then blowing them into gaseous form at launch time, reusable rockets become possible. If your rocket uses only solid fuel, that means you’d need to throw away (or reuse) all of its stages every time you wanted to launch again. However, if your rockets use liquid fuels—like Falcon 9’s first stage—you can simply allow these fuels to cool back down after they have done their job of lifting off your payload into orbit.
For most of us, there’s little difference between liquid oxygen (LOX) and methane on an everyday level. Both are easily accessible in our homes or places of work. But when you apply high temperatures to them they can take on very different forms: LOX becomes gas, while methane becomes a liquid (called natural gas). When liquids are cooled back down again they solidify.
This means that if you want to re-use your rocket over and over again—by allowing its propellants to cool after each flight—you need to find ways of keeping them in liquid form during transport so that they don’t freeze into unusable ice crystals during storage. It sounds like a simple problem, but it can be incredibly hard to solve.
The future of space travel
The world has always been fascinated by space travel. Sure we’ve made significant progress over the past few decades with bigger rockets and faster shuttles but there are still major hurdles we have to overcome. Heavy reliance on liquid oxygen means that liquid fuels are volatile, which isn’t ideal when you’re travelling into outer space. We need something safer and more efficient to reach our goals of deep space exploration. Enter methane fuel. Unlike liquid oxygen-based rockets, methane can be stored in liquid or gaseous form at room temperature so there’s less risk of explosion or fire – a crucial factor for a long-term trip into space.
Unlike liquid oxygen-based rockets, methane can be stored in liquid or gaseous form at room temperature so there’s less risk of explosion or fire – a crucial factor for a long-term trip into space. And by harnessing methane power in fuel cells that use light from solar panels to generate electricity onboard (similar to how an electric car works), we don’t need to store massive amounts of extra propellant for future missions. This system was used for NASA’s Dawn mission launched in 2007, where solar energy turned hydrazine into ammonia to power thrusters throughout its course through space – something that would have been impossible with conventional fuels. The new system not only reduces carbon emissions but also dramatically cuts down costs by nearly $500 million.
However, methane isn’t quite as efficient at getting us through space. Though more efficient than liquid oxygen-based rockets, rocket engines tend to use about 3.8 million pounds of air per second for combustion and travel – meaning there’s only about half that amount of propellant for every pound of payload being carried (nearly twice as much if you’re just carrying people). The tradeoff seems worth it though; imagine how much faster space travel would be if we could halve our current time spent in transit! There are plenty of reasons to be excited about what’s happening at SpaceX right now. What used to take days or weeks to reach other planets in our solar system will soon take just a few hours with methane fuel.
As we mentioned earlier, methane has many benefits. It burns cleaner than many hydrocarbon fuels. Additionally, as a solid or liquid at standard temperatures and pressures, rocket engines can use methane in existing designs with relative ease. This is an important step for SpaceX as it develops its reusable rockets to be used by space tourists in suborbital flights that could lead to private missions to Mars. Methane-based propellants have been around for decades—but until now they’ve been prohibitively expensive compared to more traditional propellants such as kerosene (used in Falcon 9) or liquid hydrogen (used in Falcon Heavy). If methane fuel proves successful in future launches by NASA or private companies like Blue Origin, we may see more organizations adopt methane/LOX systems over time.
In addition to reducing cost over time, methane engines also have an advantage in launch location. The Martian atmosphere is much thinner than Earth’s atmosphere; approximately 0.6% of Earth’s total atmospheric mass. This means that less thrust is needed for orbital liftoff when launching from Mars (approximately 0.13 vs 1 g) than from Earth. Methane/LOX systems can make use of up to 75% of their potential thrust from sea level to orbit without any modifications—leaving less thrust required during launch when launching from Mars compared to other propellants (such as RP-1). This could make interplanetary travel more feasible with current technology while still keeping costs low.
If methane proves successful in future launches by NASA or private companies like Blue Origin, we may see more organizations adopt methane/LOX systems over time. Although its use could be high-risk at first due to a lack of experience with methane-based propellants. At their core, these engines represent a shift towards cheaper and cleaner rockets that may allow for easier long-term space travel—whether that’s interplanetary travel within our solar system or trips to Mars. No matter what path these engines take us down in future years ahead, they’re an exciting step forward in rocketry!