By Urvashi Chitnavis
“You want to wake up in the morning and think the future is going to be great – and that’s what being a spacefaring civilisation is all about. It’s about believing in the future and thinking that the future will be better than the past. And I can’t think of anything more exciting than going out there and being among the stars.”
-Elon Musk, CEO and Lead Designer, SpaceX.
Elon Musk’s SpaceX has a long history of making the impossible, possible. It appears that now the private space agency is at it again. For most of us, travelling to Mars may seem like a far-fetched concept that would require several decades of careful planning and funding. However, Musk appears to be all prepared to charge ahead, in efforts to be the first to make it to the Red Planet. On March 1, Musk published an academic paper in the journal New Space that detailed his plans to send SpaceX’s first flight to the Red Planet by 2022. According to Musk’s estimation, the first manned crew should reach Mars a mere two years after launch—by 2024.
What is special about SpaceX’s project?
There have been several proposals of crewed missions to Mars over the years, but none have ever come through. This is not, as we might think, due to any major lack in technological advancement. In fact, most of the technological challenges such a mission may face have been or can be solved. The deciding factor for why humans haven’t landed on Mars yet, is money. The cost of such a large-scale project is massive, which governments and private firms alike, are hesitant, or in some cases, unwilling to fund. However, Musk and his team appear to have figured out this issue.
How does SpaceX plan to fund the Mars mission?
The key to SpaceX’s Mars mission is their newest piece of technology—a magnificent, 48-metre-tall, 85-tonne rocket, nicknamed the Big Falcon Rocket (BFR). As Musk stated in his paper, “The most important thing that I want to convey in this presentation is that I think I have figured out how to pay for it. That is very important.”
All rockets developed till date that can be launched into orbit, have been either expendable, or only partially reusable. In Elon Musk’s words, “It is really crazy that we build these sophisticated rockets and then crash them every time we fly. This is mad.” SpaceX engineers addressed this issue by envisioning a new kind of space vehicle—one that has often been proposed, but never actualised. The BFR, once it is ready, will be the first of its kind, fully reusable—a game changer for space travel.
However, building such a rocket requires massive amounts of money. In order to generate revenue, Musk plans to design the BFR so that it completely renders older rockets obsolete. At present, SpaceX gets most of its revenue from launching satellites into orbit and servicing the International Space Station. Till now, this has been done using their three major launch systems—Falcon 9, Falcon Heavy and Dragon. However, Musk intends to perfect BFR to such an extent, and make it so versatile, that SpaceX’s products become redundant, In turn forcing the firm to use only the BFR while providing services to its other clients.
In other words, BFR will cannibalise its sister rockets, such that eventually, all the current services performed by SpaceX will be executable by BFR. This means that all the resources that are currently used for Falcon 9, Falcon Heavy and Dragon can be devoted to a single system. The revenue generated from launching satellites and servicing the space station should then suffice for the to develop and maintain BFR.
What’s BFR going to look like?
Once ready, BFR will be 48 metres in length, 9 metres in diameter, and weigh 85 tonnes. This means that the rocket will be able to launch a larger number of small satellites in one go, than has ever been done before. The giant rocket will also be able to launch a satellite that is almost 9 metres across—the largest ever to be launched by humans. In fact, Musk mentioned in his paper that BFR could even be used to go around and clean up space debris, which is something that will very likely be required in the future.
But here’s the really interesting statistic—BFR will have a payload of 150 tonnes—that’s over 150,000 kilograms,the largest amount of consignment that any rocket has been able to carry in one launch, till date. This is an even greater rocket capability than NASA’s Saturn V, which was used for the Apollo missions.
Although one would assume such a massive rocket would cost a tremendous amount of money, surprisingly, BFR’s launch costs are fairly marginal. According to Musk, BFR will eventually provide the lowest marginal launch cost of any SpaceX vehicle, despite being incomparable in terms of size, payload, and rocket capability. Although the rocket might be a huge investment at present, in the long run, it is our ticket to affordable space travel.
The beauty of BFR is that it doesn’t have to be limited to jsut space travel. What if this same rocket were used to go from one place to another on Earth itself? Musk and his team looked into the results, and found that Earth to Earth transport with BFR could be done at 27,000 kilometres an hour. This means that a typical ”long-distance” trip would take less than half an hour. And once you exit Earth’s atmosphere, there’s no friction, and no turbulence.
Making a space vehicle reusable means greatly adding to its weight, which is bound to create some stress on the rocket’s engine and fuel reserves. BFR will need to hold 1,100 tons of propellant, and this requires a giant deep cryo liquid oxygen tank, with an internal volume of a thousand cubic metres. At this tremendous pressure, there must be no risk of the tank material giving way.
To make the rocket function safely and effectively, SpaceX engineers created a new material—one that can safely house the vast amount of propellant that will be required by BFR. They developed a new carbon fibre matrix that is much stronger, and more capable at storing cryogenic fuel than anything available before.
The next important aspect is the engine. Around 2011, SpaceX began developing Raptor engines, a family of cryogenic engines that use methane and liquid oxygen (LOX) as a fuel, as opposed to the RP-1 kerosene and LOX used in most of the Falcon series engines. The Raptor series was, in fact, conceptualised keeping the vision of interplanetary travel in mind. According to Musk, this design would be able to achieve full reusability of all rocket stages and, as a result, “a two order of magnitude reduction in the cost of spaceflight”.
The BFR Raptor engine is expected to be the highest thrust-to-weight engine in history. The ship engine section will comprise four Raptor engines surrounding two smaller engines. With each engine, there is a lot of redundancy, which brings the landing risk close to zero. In fact, if anything happens to go wrong with either of the centre engines during landing, the ship will still be able to land safely with the other functional engine. The real vision is for humans to reach Mars, and this involves a significant risk for the astronauts involved. But SpaceX is leaving no stone unturned in making the mission as safe as it can possibly be. According to Musk, once the rocket is ready, it will have a landing reliability that is on par with the safest commercial airlines.
In fact, it might not be so far from commercial flights in comfort level, either. In Mars transit configuration, BFR will have 40 cabins, with two to three people per cabin, a central storage area and galley, a solar storm shelter, and an entertainment area. To put this in perspective,this is just the first version of the design.
However, one of the most elegant features of this ambitious project is orbital refilling. The rocket has been designed to automatically be refuelled, while in orbit, by a tanker, via a beautifully precise docking procedure. In fact, as mentioned in Musk’s paper, if the tanker has high reuse capability, you are essentially only paying for the cost of propellant—and the cost of methane and oxygen is very low. This is how, bit by bit, Elon Musk’s vision of affordable interplanetary travel begins to materialise.
But what happens once we get to Mars?
In Musk’s words, “Being a multi-planet species beats the hell out of being a single planet species.” BFR is, at the end of the day, simply the vehicle that will get us to the Red Planet. But what next? SpaceX seems to have that part figured out as well.
Musk is hopeful that by 2022, the first cargo ship will rendezvous with the Red Planet. The goal of this first mission will be to find the best source of water. The second mission will be launched in 2024 and will involve four ships, two with cargo and two with crew.This mission will be aimed at setting up a propellant plant on the planet. Mars has a carbon dioxide atmosphere and plenty of water ice., and with the right reactions, you can use these to end up with methane and oxygen—the constituents of Raptor rocket fuel.This is how, step-by-step, ship-by-ship, a Martian city begins to be built.