If you look into the night you can see the Moon our nearest neighbor. Humans have been there a few times but we aim to “shoot to the moon” more permanently and sustainably. We can see Mars, a planet which sits in the cross hairs of our exploration with its raw resources and atmosphere which could be used to build a civilization. We see other places in our Solar System and beyond that every science fiction movie advertises as our future homes, as places where humanity can unabashedly grow without the looming threat of global catastrophe and scarcity of resources.
The future of humanity is in the stars, but how do we move toward it? Governments seem ambivalent, and today it seems with the retirement of the shuttle and lack of a sustained space vision that we are less capable of spaceflight than we were in the days of our parents. Are we going anywhere anytime soon?
Any object that has traveled into space is worth its weight in gold. For the past 30 years the price to go to Earth orbit has been $10,000 a pound ($20,000 a kg). Any mission to Mars or the Moon must first travel through the gateway of Earth orbit meaning that economically, our ambitions to travel beyond stand as unsustainable pots of gold at the end of the rainbow.
The staggering cost of spaceflight has been the single biggest deterrent to extending our reach beyond Earth orbit. Only light-weight robotic missions are even fiscally capable of being implemented. During the early 1990’s the Space Exploration Initiative quoted $500 billion as the cost of a human Mars mission. The many permutations of Mars missions considered by NASA ever since have not been able to lower the bill.
There is no way to become a space faring civilization with costs this high. Perhaps flags and footprints can be left, but not a sustainable system capable of sprouting a colony on another world.
Yet there is a change in the wind. Namely a new company called SpaceX is driving costs down. SpaceX’s Falcon 9 rocket currently boasts a cost per pound to orbit of $1,800. The falcon heavy, a rocket in development, claims a cost less than $1,000 per pound (less than 1/10th the traditional cost). Even more exciting, the company is working on saving and reusing parts of the rocket to drive the cost down by another factor of 10.
To put it in context, imagine you’re an astronaut traveling into orbit. The cost of launching you, and your support equipment with Russia is around $70 million. With SpaceX the cost has been reduced to below $7 million and has potential to drop to under $700,000.
You might ask why is the cost of spaceflight so exorbitant and how can one company make such a difference? The major factor is sustained vision. John F. Kennedy was the leader of the space age. His leadership and consistent goal of reaching the moon provided the stability required for the Apollo program. Unfortunately after president Kennedy, no leader emerged with a sustained vision for humanity in space. Today there are approximately 500 different visions for US spaceflight in congress. Leaders consistently fight over the destination, (Moon, Mars, or Asteroid) the budget, the location of the jobs supporting the mission, etc. Typically projects only last the stretch of a political cycle.
It’s no wonder that government contractors have to charge so much. When projects are consistently being canceled, moved, and re-prioritized, a manager must charge many times the actual cost to cover the risk that they may lose their contract the next day.
Elon Musk the founder and CEO of SpaceX is a man with a vision. As early as 2000 he set his sights on extending humanity’s reach to Mars. He began by attempting to raise money for the Mars Oasis project to place a greenhouse full of plants on Mars. He ultimately learned from the Mars Oasis project that access to space was too expensive to accomplish his goal. He then shifted his focus to create SpaceX to develop cheap access to space and ultimately access to Mars.
The Space Shuttle is one of the most advanced spacecraft systems in existence. The shuttle’s liquid oxygen, liquid hydrogen staged combustion cycle engines achieved a vacuum specific impulse of 450 seconds, quite a feat of engineering. The Falcon 9 uses a less advanced gas generator cycle, kerosene liquid oxygen cycle and only achieves a specific impulse in the lower 300’s. Yet, just like the difference between a sports car and a work truck, the simpler technology with lower performance costs less and can get the job done. Whereas the shuttle focused on pushing the performance of the system the Falcon 9 focused on cost and manufacturing.
Everything at SpaceX is focused on scalability. Every part from the engines to the tanks to the rocket fairings are built like LEGO pieces that can be mixed and matched. The Falcon Heavy Rocket is literally three Falcon 9 rockets strapped together.
In contrast the Space Shuttle was designed by a concert of seven different companies with highly distinct systems resulting in a marvel of system engineering but couldn’t deliver on the original promise of cheap, repeatable access to space.
Reusability is the true key piece of the puzzle. With sustained leadership and a focus on scalability the price of space access can drop by a factor of 10. To drop the price by a factor of 100 the rocket must be reusable. Elon Musk puts it this way:
“The way rockets work now is they’re expendable. You buy them, then throw them away. Imagine if other means of transport were expendable – planes, cars, bicycles, horses. A 747 costs a quarter-billion dollars, and you would need two for a roundtrip. But nobody is paying a half-billion dollars to lunch in New York.”
The typical cost of the fuel of a rocket is less than 1 percent of the cost of the rocket as a whole. If the rocket could be reused then you could purchase a rocket 99% off. SpaceX is actively working towards reusing the first stage of the Falcon 9 and ultimately the entire rocket. They plan to land the fist stage of their next mission on a barge.
At the end of the day what is the actual cost saving that can be achieved? I would break it into three categories: near term, medium term, and long term. Near term decreases in the cost are mostly attributed to modularity and manufacturing and have largely been achieved as the Falcon 9 is currently quoting $1,800 per pound to orbit. The medium term decreases in cost will be largely due to scaling of the rocket. As mentioned the Falcon heavy is quoting $1,000 per pound and the methane BFR rocket (literally stand for Big F#!#&# Rocket) in early stages of development has a target price of less than $500 per pound. Realistically the Falcon Heavy is still a few years and the BFG could be a decade or more. A wild card is the reusability and I would classify it as a long term savings. There is a clear path to reusing the first stage because of its relatively low speed and altitude make the performance hit small. The second stage however is more difficult. It would need either a large heavy heat shield or a sizable amount of propellant to return to Earth. If the first stage can be easily reused in the near future it could reduce the cost of spaceflight by as much as a factor of two but likely a bit less. There are fixed costs such as insurance, operations, refurbishment, and other factors that reduce the savings achievable from reusablility. In addition second stage reusability may not be a reality.
At the end of the day the cost savings compared to traditional spaceflight achievable now is around a factor of 6, in the next few years that will go to a reduction by a factor of 10, and in the next decade a factor of 20. To be reduced from $10,000 per pound to $500. Will it be enough to shatter the low-Earth orbit glass ceiling humans have been constrained by since the Apollo mission? I think so.
Aside from SpaceX, there are companies working on the cost of spaceflight. Some of which have made great strides recently. While not at near term as SpaceX they are working on game changing technologies.
The Skylon is a single stage to orbit air breathing rocket which has been the brain child of a British innovator Alan Bond. The allure of an air breathing rocket is the huge reduction in the mass of the oxidizer. Typically the oxidizer comprises more than half the mass of the rocket on the launch pad. If a reasonable fraction of that oxygen could be replaced with oxygen from the atmosphere then one could make an argument for ditching the second stage and making a “Space Plane” which would be more akin to an airplane than a traditional rocket. Using the engine in this fashion allows the Skylon to reduce its required propellent and boast a phenomenal effective specific impulse of 2800 s or almost ten times that of conventional rockets.
For years the Skylon (and its predecessor HOTOL) had a technical problem that prevented further development of the air breathing rocket. When traveling at Mach speeds, the atmosphere forms a superheated bubble around the aircraft. To utilize the scorching air from the atmosphere the air would need to be cooled from around 1,800 ºF (1,000 ºC) to -230 ºF (-150 ºC).
In 2012 the Skylon team demonstrated a successful precooler that utilized supercooled liquid helium traveling though micrometer scale ducts to achieve the decrease in temperature necessary for an air breathing rocket. Success has attracted more funding from the British government and a path forward to develop a full scale engine. The Skylon is still a wildcard, but the air breathing single stage to orbit technology has the potential to disrupt even SpaceX. The Skylon would likely be at least two decades away from commercial feasibility and may encounter other issues, but it is a concept well worth watching develop.
Another possible player is the Stratolaunch Systems funded by Microsoft mogul Paul Allen. Currently in the Mojave Desert an aircraft is being built that has the largest single payload lift capacity of any aircraft in existence and the largest wingspan. The goal is to lift an entire rocket to 50,000 feet into the stratosphere where it could be dropped from the aircraft and launched regardless of weather conditions anywhere on the planet. Originally a Falcon 9 was planned as the carry rocket, but Orbital Sciences has stepped in with a new rocket design based on their current aircraft launched Pegasus design. Realistically the Stratolaunch may be more of a niche project offering independence of weather and global location. However the concept of launching a rocket from an aircraft has some potential. The Stratolaunch aircraft is planned to fly in 2017.
When I started as an undergraduate at Embry Riddle in Aerospace Engineering I had one one goal – make the Solar System humanity’s back yard. I originally thought that I would be working on access to space. However I can see now that access to space is a problem that is being solved. I can move to focusing on the next step – moving from the orbit gateway to the frontiers of the Solar System. Thank you SpaceX. Without you and those like you, I wouldn’t be able to follow my dreams of Mars and beyond.