Affordable Access to Space
Rockets are 20th-century technology. A government effort to develop new launch technologies could open the door to a vast array of new opportunities for space exploration and development.
The high cost of reaching orbit is the major factor preventing the large-scale exploration and exploitation of space. When I fly from College Station, Texas, to almost anywhere in the United States, I pay $4 to $8 per kilogram (kg) of me. When a satellite is launched into space, the customer (or taxpayer) pays approximately $10,000 to $20,000/kg. Space travel will not become affordable until the age of rocketry is replaced by an age of new propulsion technology—and only government action will make that happen.
Since Sputnik inaugurated the space age in 1957, chemical rockets have propelled every payload into orbit and beyond. Rockets work well, but they are expensive. Their high costs have restricted access to space to the governments, corporations, and organizations that can afford tens or hundreds of millions of dollars to launch a satellite. Consequently, half a century after Sputnik, only a few hundred tons of payloads, the equivalent of two Boeing 747 freighter flights, reach orbit annually. The number of people who have reached orbit since Yuri Gagarin in 1961 could fit into one Airbus 380.
Nor are rockets fully reliable. Their failure rate while carrying communications satellites to geosynchronous orbit in 1997–2006 was 8%. Taurus booster failures in 2009 and 2011 cost NASA $700 million in lost satellites. Insuring a communications satellite from launch through its first year of operation costs 11 to 20% of the total cost, which is two orders of magnitude greater than for a Boeing 747.
For $125 million, an Atlas V will lift 9,000 kg to low Earth orbit for $14,000/kg, which is much less than the $25 million for the 1,300 kg carried by a Taurus at $19,000/kg. Future developments promise some improvement, but even reducing costs by an order of magnitude, a goal not envisioned by rocket advocates in the next decades, still means a dauntingly high cost. The much-heralded Virgin Galactic space tours cost $200,000 per person (approximately $2,000/kg) but will go only 60 miles up, far below Earth or-bit and demanding an order of magnitude less energy.
Under current trends, the technology for reaching orbit in 2030 and beyond will be essentially unchanged from 1957. This continued dependence on rockets is not for lack of effort. Since the introduction of the space shuttle in 1981, the National Aeronautics and Space Administration (NASA) alone has spent over $21 billion on cancelled rocket programs such as the X-33. The military also has its share of cancelled projects, such as the Rapid-Access Small-Cargo Affordable Launch (RASCAL).
Efforts by private firms to develop rockets over the past two decades have largely floundered or become dependent on government funding. The problem is not incompetence or ineptness of governments, corporations, or individuals (although overly optimistic statements have created unrealistic expectations), but the very challenge of leaving Earth. The phrase “It’s not rocket science” is part of popular culture for a reason. The technology of designing, building, and launching a rocket into a harsh, unforgiving environment is very demanding.
Why, if the cost and reliability of rockets limit space exploitation and exploration, have alternatives not been developed? First, rockets fulfill existing limited demand sufficiently well to deter the development of alternatives. Indeed, the entire space industry revolves around chemical rockets. The situation is analogous to airplane engine technology in the 1930s, when the efficiency and output of piston engines increased even as their theoretical limits were becoming increasingly apparent. The military demands of World War II and the Cold War greatly hastened the development of the jet engine. No such pressing urgency exists today for rockets.
Second, proposed alternatives to rockets are technologically immature. Moving from the laboratory to practical application will demand billions of dollars over many years. The perceived benefits are too distant for industry or nonprofits to invest serious resources. Only the federal government can provide the sustained commitment over many years that is necessary for development.
And now for something completely different
The goal is not to develop new technologies for technology’s sake, but to develop technologies to drastically decrease the cost of reaching orbit.
One reason why rockets cost so much is that over 90% of a rocket’s weight is fuel and expendable rocket stages. The actual payload is only a few percent. The alternative to the rocket is a ground-based system (GBS), which keeps the engine and most of the fuel on the ground, so the spacecraft is almost all payload, not propellant. As well as being more efficient, GBS is inherently safer than rockets, because the capsules will not carry liquid fuels and their complex equipment, eliminating the danger of an explosion.
As with any technology in its formative phase, a range of possibilities exists. Leading contenders include beamed energy propulsion and space elevators. Magnetic levitation and light gas guns have less potential. Most important, the alternatives have the potential to reduce the cost per kilogram by up to two orders of magnitude to $200/kg.
In beamed energy propulsion, a microwave or laser beam from the ground station strikes the bottom of the capsule. The resultant heat compresses and explodes the air or solid fuel there, providing lift and guidance. Researchers in the United States and Japan have propelled small models by lasers and microwaves, demonstrating proof of the concept.
Space elevators employ a thin tether attached to a satellite serving as a counterbalance tens of thousands of kilometers above Earth. A platform holding the payload crawls up the tether. Generating more publicity and better art than beamed energy, this concept depends on the development of materials strong and light enough to serve as the tether.
Magnetic levitation and magnetic propulsion systems would give a high initial velocity to a spaceplane, which would then use a scramjet or rocket to propel itself into orbit. These are not true GBSs, but ways to replace the lower stages of a rocket with a more efficient, less costly way of reaching the upper atmosphere.
The idea of employing a gigantic gun to launch space capsules received a very public unveiling from Jules Verne in his 1865 From the Earth to the Moon. Serious development occurred a century later when the U.S. and Canadian governments funded the High Altitude Research Project (HARP) by Gerald Bull in the 1960s and the Super High Altitude Research Project ♯ at Lawrence Livermore Laboratory in the 1980s and 1990s. Instead of igniting a conventional propellant, the gun compressed a low–molecular-weight gas such as hydrogen to produce a higher velocity. The small projected payload of only 1 kg helped lead to the project’s cancellation. Growing interest in picosatellites, which weigh less than 1 kg, however, may revive interest in very small payloads.
A game changer
The concept of GBS encompasses a range of technologies with payloads ranging from a kilogram to hundreds or thousands of kilograms. All assume a high frequency of launches, so that a GBS system could launch thousands of tons per year, an order of magnitude more than current launchers.
GBS should greatly change thinking about satellite design, function, and operations. The high cost of reaching orbit means satellites today are built to maximize yield per kilogram, which results in high costs to develop, assemble, and test satellites. GBS would provide designers with several options: an unchanged satellite with sharply lower launch costs; heavier but less expensive satellites; bigger, more capable satellites; and smaller, less capable satellites.
GBS will strengthen current trends toward distributing functions among many satellites and building picosatellites, nanosatellites (which weigh between 1 and 10kg), and microsatellites, which weigh between 10 and 100 kg. The satellite systems of 2030 may consist of clusters of satellites, each specialized but operating together.
Satellite operators may decide to launch a satellite by traditional rocket but send its fuel by GBS. NASA and the Department of Defense have started to investigate orbital refueling and replenishing. GBS could provide an incentive to develop these and related technologies to rendezvous, dock, transfer liquids, and build larger satellites in Earth orbit. Similarly, launching arrays of solar cells by GBS and attaching them to a satellite in orbit might meet satellites’ growing demand for more electricity.
The lower launch costs will reduce the need to maximize operational efficiency per kilogram. Satellites may grow in size and weight but drop in cost as engineers rethink their criteria for success. The development of standard structures, components, and modules may finally bring the efficiency of large-scale production to satellites, further reducing satellite costs and thus encouraging more actors to explore and exploit space.
Expanding existing services such as communications and remote sensing is an obvious market for GBS. By significantly reducing the barriers to entry posed by high launch costs, GBS should create obvious new markets such as providing propellants, water, and other bulk supplies to satellites and larger facilities in orbit.
The real radical promise of GBS is creating new markets made possible by both sharply reduced launch costs and the ability to launch thousands of tons annually. Just as the Erie Canal aided the western expansion of the United States in the 1820s by reducing the cost and risk of moving people, products, and produce, so too will GBS encourage and promote commercial exploitation and scientific exploration of space.
The 1994 NASA Commercial Space Transport Study identified many potential markets, including the long-expected space manufacturing and biopharmaceuticals, but also more provocative ideas such as orbiting movie studios, space debris disposal, and burial of nuclear waste. The report expected these markets to emerge only if launch costs dropped to hundreds of dollars per kilogram.
Perhaps the two most intriguing potential “killer apps” are solar power generation and nuclear waste disposal in solar orbit, two markets that could consume thousands of tons of launch capacity annually.
Space-based solar power (SBSP) promises gigawatts of electric power with minimum environmental damage. Too ambitious when proposed in 1968, technological advances and growing concern about providing environmentally friendly baseload electricity have renewed interest in collecting solar energy in orbit and transmitting it via microwave to Earth. Studies by the National Space Security Office of the Department of Defense in 2007 and the International Academy of Astronautics in 2011 concluded that constructing a one-gigawatt solar power station in geosynchronous orbit was technically feasible. The economics of launch costs, however, were another matter.
At $20,000/kg, launching the 3,000 metric tons of material and equipment for a SBSP station would cost an impractical $60 billion. At $200/kg, the launch cost would be $600 million, a much less daunting financial obstacle. For SBSP to become a reality, reducing the cost of reaching orbit is as important as the technology.
A less technologically and politically challenging market for GBS to serve is beaming electricity from a small SBSP to other satellites. The Air Force’s energy plan through 2025 considers this a desirable and transformational technology.
Even more unconventional is safely disposing of nuclear waste, a political, technical, and economic nightmare with no widely accepted solution. Historically, garbage has been buried or recycled. The idea of launching waste into space instead of burying it seems counterintuitive and dangerous. From an aerospace perspective, space is for satellites, not garbage. Neither the aerospace nor nuclear engineering community is advocating for space-based nuclear waste disposal, but GBS could change their thinking.
GBS could make disposing of nuclear waste in space economically and technically feasible. The concept is simple: A GBS system would launch capsules either directly to their destination (solar orbit or into the Sun) or into a high Earth orbit. If the latter, a solar sail or electric engine would then propel the capsule to its destination. The capsule, of course, would consist primarily of shielding and other technology to ensure the safety and integrity of the waste.
Space-based disposal may not only permanently solve a problem that threatens the future of nuclear energy but also fund GBS development and deployment. The Department of Energy expects to spend over $100 billion burying 50,000 tons of tons of high-level spent commercial fuel, a cost of approximately $1000/kg. Reactors elsewhere in the world have produced another 200,000 tons. A huge market exists to eliminate this waste. If space-based disposal proves politically, economically, and technically feasible, then shifting some of the billions of dollars destined for underground storage could fund GBS.
Roadmap to space
If GBS is such a good idea, why has it not been developed? The good news is that researchers have demonstrated that GBS concepts are theoretically feasible; the bad news is that these concepts remain in the laboratory. On the nine-stage Technology Readiness Level (TRL) scale that NASA and the military use to judge the maturity of a technology, GBS technologies are at TRL 1 or 2, still in the early stages of proving their practicality and worth. GBS faces the classic technological chicken-and-egg conundrum: Demand is too low to justify developing new technologies to reach orbit because the conventional cost of reaching orbit is so high that it depresses demand. This cycle can only be broken by government action.
For GBS to evolve into a mature, functioning system will require a sustained commitment of billions of dollars over many years. Developing GBS is a legitimate and necessary role of the federal government. Historically, the federal government has supported the development, construction, and operation of transportation infrastructure, including roads, canals, railroads, airways, and highways. Most pertinent, by 1957 the U.S. military had spent more than $12 billion (over $90 billion in current dollars) developing rockets. Without government funding in the 1950s, there would have been no NASA space program in the 1960s.
Rocket development received government funding because of the understandable market failure of the private sector and nonprofit organizations. In the 1920s and 1930s, individuals and private groups in Europe and the United States tried building their own rockets. They quickly discovered that rockets demand a commitment of financial, scientific, technical, and human resources far beyond what they could muster. Only a government could provide those resources. Since the 1930s, every country that has developed rockets had the state play the major role in funding and guiding those efforts, whether civilian or military.
Moving GBS from lab to launch will be a long journey of many steps. The immediate goal is to establish strategic roadmaps with metrics to enable proponents, patrons, users, and analysts to judge progress across competing approaches. A partial model to emulate is the 2011 Defense Advanced Research Projects Agency–NASA—organized conference that studied what technologies would be needed to build a starship.
Crucially, a conference to develop a GBS roadmap must include potential as well as existing rocket users, who need to consider how a radical reduction in launch costs would alter how they conceive of spacecraft and their applications. GBS designers need to know what existing and new users want, such as the minimum acceptable payload weight and maximum acceptable acceleration. Involving users will also create stakeholders to support GBS.
This roadmap conference will create criteria to judge the development of GBS. These paper studies will cost very little. The next step will be laboratory studies to climb the TRL ladder. Depending on the desired pace, this stage will demand millions or a few tens of millions of dollars annually.
The current low levels of technological maturity offer both challenge and opportunity. GBS covers several competing approaches, with many alternatives within each approach. The United States should not make the mistake that the nuclear power industry and Atomic Energy Commission made in the 1950s and 1960s when they focused on the technology closest to commercialization instead of the type of reactor best suited for civilian power generation. The government must carefully establish a level playing field among competing approaches lest it foreclose on a longterm promising technology.
Only after a few years will funding significantly increase as development moves from component and proof-of-concept testing to integrated prototypes. At that point, decisions must be made about whether GBS is sufficiently promising to merit significant funding and, if so, which concept or concepts to advance. This research may prove that expectations were unrealistically optimistic. If so, better to know that earlier than later and to realize that rocket technology will indeed continue to dominate access to space.
GBS needs an agency to nurture it until it is ready for commercialization. Candidates are NASA and the Department of Energy (DOE). NASA is the obvious but not necessarily the best sponsor because of its focus on rockets. The agency’s 2010 Technology Area Breakdown Structure of its Space Technology Roadmaps includes only “ground launch assist” as part of possible future launch propulsion systems, indicating a lack of current institutional support for GBS.
The DOE may offer a more inviting home, especially if its new Advanced Research Projects Agency–Energy (ARPAE) administers the research to move GBS up the TRL ladder. Because the DOE has less invested institutionally in rockets, it may prove a stronger sponsor. Furthermore, many GBS technologies are electrical in nature, necessitating a different skill- and mindset than that of NASA’s rocket engineers and scientists. Indeed, changing launch systems will demand changing existing ways of organization, funding, thinking, and acting, as well as developing the new technologies.
The search for alternatives to rockets is not exclusively a U.S. endeavor. The International Symposiums on Beamed Energy Propulsion (ISBEP) have attracted engineers and scientists from Japan, China, Russia, Brazil, South Korea, and other countries. Because the level of investment is so low at this stage, international cooperation in exploring GBS alternatives may be easily accomplished. Possibly a bit of friendly national competition might accelerate GBS development.
GBS may prove more promise than potential. The technological challenges may prove overwhelming or the costs too similar to those of rockets to justify development. But unless a dedicated effort tests that potential, low-cost access to space will remain in the realm of science fiction.
Developing GBS will be expensive, but the failure to create low-cost access to orbit will be even more expensive by delaying the large-scale exploration and exploitation of space. As with nuclear fusion research, the potential is great. Unlike fusion research, the time to success will be much shorter—if the effort is made. Just as government funding developed the technology that enabled humanity’s first footsteps into space, so too can the government development of GBS make the second half-century of the space age even more exciting than the first.