SpaceX Dragon's ultimate mission is Mars colonization
By David Szondy
February 5, 2012
The private spaceflight company SpaceX declared that 2012 would be the "Year of the Dragon" - a play on the current cycle of the Chinese calendar and the upcoming tests of SpaceX's Dragon space capsule. For a time, it seemed as if SpaceX was regretting that slogan. Dragon was chosen as one of five competitors for NASA's Commercial Orbital Transportation Services (COTS) contest to develop a cargo/passenger craft to service the International Space Station. The Dragon program had enjoyed considerable success and was scheduled to be the first private spacecraft to visit and, if all went well, dock with the International Space Station (ISS). Unfortunately, with the need for more testing of the Dragon capsule delaying the launch from its original February 7, 2012 date to late March or even into April, it looked as though the Year of the Dragon was starting a bit late.
Then Roscosmos, the Russian space agency, suffered another in a string of space mishaps that saw the grounding of the manned Soyuz-TMA spacecraft after a booster malfunctioned on a Progress cargo rocket in August 2011. Things were then compunded by the failure of the Phobos-Grunt Mars probe that was trapped in low Earth orbit and eventually destroyed on re-entry when its engines failed to fire. Now sources in Russia report that a failure of the pressure capsule of the Soyuz TMA-04M spacecraft has postponed the next passenger flight to the ISS from March 30, 2012 to sometime in late April or May. With the Soyuz-TMA currently the only way of taking crews to and from the ISS, the reliability of the Russian spacecraft coming into question only highlights the growing need to provide the station with alternatives to Soyuz and Progress.
Add to this the successful test of SpaceX's SuperDraco rocket engines for the Dragon spacecraft and the ambitions of Elon Musk, the founder of SpaceX, and the month's delay looks on the order of stopping to buy a newspaper at the airport before heading off to conquer Mount Everest. Or in Musk's case, the planet Mars.
Though the next step SpaceX's Dragon spacecraft is a rendezvous and possible docking with the ISS, Elon Musk's publicly stated final goal for the Dragon is much larger: The colonization of the planet Mars. In a recent interview with New Scientist magazine, Musk said that he wants to see 10,000 people living on Mars in the near future - preferably, millions of people. To help bring this about, the ultimate goal for the Dragon spacecraft is to execute a manned landing on the red planet within 20 years. Not only that, but Musk plans to do it at a mission cost of only US$5 billion dollars - maybe even as low as US$1 billion.
As the centerpiece of such lofty ambition, the Dragon hardly looks up to the job. At 9.5 feet (2.9 m) high, a diameter of 11.8 feet (3.6 m) and weighing 9,260 pounds (4,200 kg), it resembles the old Command Service modules of the American Apollo program that reached the Moon in the late '60s and early '70s. It even has a similar configuration with a return capsule forward and a support module containing engines and support systems aft.
This is not an accident. It's part of the potentially greatest revolution in space flight since Sputnik was sent into orbit by the USSR in 1957. For decades after that first launch, space flight was a government monopoly. Even when private companies started going into space in the 1990s, it was only as providers of launch services to send commercial and government satellites into orbit. Now, all that is changing as private enterprise takes over space exploration in a manner not seen since the early days of the Hudson's Bay Company. Over half a dozen companies are working on sending tourists on suborbital pleasure flights while others are testing orbital hotels.
There are also plans for private lunar landings and private lunar bases. Meanwhile, the United States government cedes manned flights to low Earth orbit to private companies while NASA concentrates on preparing for sending crews on deep space missions. It's beginning to look as if the race to build the first lunar base or achieve a manned landing on Mars won't be between the United States and China, but private companies.
NASA's COTS program includes five companies developing space freighters and passenger craft to service the ISS. Dragon is one of these craft, but for Elon Musk the space station was never more than a stopping off point on the way to reaching the planet Mars. In fact, every phase in the development of Dragon and the Falcon rockets that hurl it into orbit have not been about just fulfilling the next mission, but on the one several steps on. This is very different from the approach that NASA took during the early days of their manned space program. In the 1960s, the American space agency was rolling out brand new models of spacecraft like Detroit did cars and just about as often. No one would ever mistake a Gemini capsule for last year's Mercury or next year's Apollo. Each were distinct craft built to fulfill distinct missions using what was cutting edge technology at the time.
Musk's approach, on the other hand, is one where SpaceX uses a form of parallel development that aims at building launchers and capsules that will carry out the client missions yet are also incremental steps in a longer development program. In this respect, this approach is similar to that of the US Navy's Polaris submarine program of the 1960s where the submarines were designed to carry the missiles that would be available ten years in the future as well as those ready to deploy at the time the boat was built. With SpaceX's launcher's and capsules, each one is an improvement on a basic design that was created with those improvements in mind. The Falcon 1 booster was built with an eye on the much larger Falcon 9, which was was built looking forward to a Falcon variant that will be larger and more powerful than NASA's famed Saturn V booster that sent the first men to the Moon. The same goes for the capsule with the first test bed versions intended as direct ancestors of the later cargo and passenger variants.
The other part of the SpaceX approach is to benefit as much as possible from the huge stores of data that NASA created for the American space program. This not only provided SpaceX with a tremendous technological treasure trove, but also a rich field of examples of how and how not to build spacecraft. Not having the financial resources of a superpower to draw on, any private space venture like SpaceX has to pay close attention to the bottom line. That means keeping costs down and that means striving for maximum efficiency. In other words, the company has to deliver payloads to orbit as fast as possible, as often as possible and charge as little per pound of freight as possible. In other other words, it has to make money.
The way Musk hopes to achieve this is by taking proven rocket designs, simplifying them and streamlining them as much as possible in order to build them quickly and cheaply. One of the problems that NASA had with keeping costs down was that from President Johnson on, the space program was seen by politicians as a way of creating jobs - especially in poorer regions of the United States. That's one of the reasons why, for example, though the NASA launch facilities are in Florida, Mission Control is in Texas and there are space centers in places like Alabama. Small wonder it cost about a billion dollars a pop to send the Shuttle into space. SpaceX, on the other hand, tries to use as few people as possible in as central a location as possible building rockets in as few steps as possible.
This borrowing from NASA's past has paid off considerable dividends for SpaceX. The Dragon's shape, for example, is derived from that of the old Apollo capsule and exploits the same slightly-steerable aerodynamic characteristics during re-entry. The heat shield of Apollo was of a very successful design that used a plastic that ablated (burned slowly away), protecting the capsule from the heat of re-entry. SpaceX took this material and when they found it too expensive, they modified it and not only brought down the cost by a factor of ten, but they improved it so the shield can be used over and over instead of being written off after one mission. The shield is also much stronger, allowing the Dragon to hit the atmosphere at the much faster speeds of returning Lunar and planetary missions.
A similar legacy item is the Dragon's escape system, which every spacecraft rated to carry people must now have. Currently, Dragon uses the system that NASA used in the 1960s - a tower with solid-fuel rockets on it. The idea is that if a malfunction should occur at liftoff, the rockets would blow the capsule free of the booster. However, that is only a temporary fix. Under a US$75 million NASA contract, SpaceX intends to eliminate the tower and replace it with its SuperDraco rockets inside the capsule itself that will fire out the sides and down, avoiding the heat shield. This might seem like a trivial development, but it's actually quite remarkable because of the next step beyond. At the moment, the rockets are intended as an escape system, but SpaceX's plan is that these escape rockets will be powerful enough and capable of throttling and restarting to allow the Dragon to make a pinpoint controlled landing at the site where it took off from rather than coming down on parachutes to be recovered at sea.
This is very significant because Musk believes that the key to making spaceflight cheap is to make the flight components reliable and that means reusable. It all works together as a self-reinforcing cycle. If the system is simple, reliable and reusable, each of these three legs of the tripod strengthens the others. Simple systems become more reliable and reusable. Reliable systems become more simple and reusable. Reusable systems become more simple and reliable. One of the maddening things about most space missions is that you build these wonderful machines that get used once and then end up as scrap or in a museum.
The only reusable system that had any success was the Space Shuttle, but that was only partly so and the orbiter was a nightmare of complexity and delicacy. What Musk wants is for the entire Dragon system, capsule and booster stages, to have the ability to fly back to base on their own. This not only means that SpaceX gets their gear back, but that they have a space system that is truly flight tested. It's no longer a matter of "this one worked, so the next one probably will", it's "This one worked, so unless it's damaged it should work again." That really boosts the success rate for a machine. Not only that, but by recovering components that have been used in actual flight, much more data about them can be recovered, allowing for further efficiencies.
However, one problem with spacecraft with landing systems is that those systems take up weight, which means less payload. To offset this, larger, more powerful engines are needed. Just as the Dragon capsule needs the SuperDraco rockets if it's going to land under its own power, the Falcon boosters need larger engines. A new Merlin 1D was developed that improved the original design by not only simplifying it, but by increasing the thrust from 95,000 foot-ponds (129,000 Nm) to 140,000 foot-pounds (190,000 Nm) and allowing throttling of all engines in a multi-engine cluster to be throttled simultaneously through a range of 70 to 100 percent. This not only makes the Falcon launcher cheaper per pound of payload, but it allows for a larger payload. In this case, that increased payload is the powered landing system for the booster components and the Dragon capsule.
Another innovation is fitting the Dragon with a solar array. This has never been done with an American manned spacecraft before. All the previous ones have relied on fuel cells. The Dragon's solar panels give the craft a much longer in-orbit duration because fuel cells only operate for as long as they have fuel. With solar panels, the Dragon can remain on station for a week in the manned version (limited now by the air and water on board) and a year for the cargo version.
This program of reliability, reusability, reduced cost, mission endurance and an attitude of "why engineer when you can over-engineer?" certainly fits in with Musk's vision of opening up the Solar System to colonization. If anything, it is one of the most ambitious, most public attempts at stirring up public support for going to Mars since Werner Von Braun joined forces with Walt Disney back in the 1950s to try to kick off the American space program. It's familiar territory when SpaceX puts up animated videos of what their new systems will be like in operation and even give the public a virtual tour of a Dragon capsule.
And it isn't all pie in the sky. NASA are already looking at using the Dragon spacecraft modified as an unmanned lander to search for life on Mars. The possibility of a lander that could touch down on Martian soil without parachutes or airbags is certainly attractive. It also has eerie echoes of the Age of Exploration when Europeans set out on voyages of discovery in off the peg merchant and war ships. Converting an orbital cargo ship into a deep space explorer is a move that Captain Cook would have approved of.
Despite or perhaps because of SpaceX's ambitions, the Dragon has produced its critics. Having the the demonstration flight to the ISS delayed until April hasn't helped and some have pointed out that while the first launch of a rocket seems the hardest, it's actually the eighth or ninth when production lines are more important than innovation that the problems start to arise. Can SpaceX's small work force maintain the quality control of a NASA? Does the inherent complexity of space travel necessitate large organizations? Will the basic and growing problems faced in getting a manned mission to Mars be too great for a private company. Worse, what about the stumbling block that all space pioneers have run into over the past fifty years: Discovering that getting somewhere is one thing, finding a reason to go is something very different.
Whatever the outcome, the problems plaguing the Russian space agency and the necessity of keeping the ISS supplied and its crews replaced makes at least the short term success of Dragon and its competitors a high priority in the months and years to come.
Here's a video animation from SpaceX showing how a Dragon mission would play out.
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