The Price

The more ambitious and innovative a space tether application, the more money will be needed for the development but also the more difficult it will be to estimate the cost and predict the benefits. The benefits, in the form of lower launch costs, enhanced capabilities, or increased efficiency, must outweigh the investments in terms of time and money. If benefits from a new development can be expected soon and the financial return on investment is high, technology development may be paid for by private industries. However, for space projects it is typical that new developments need to be at least partly financed by government space organizations, because for industry the financial benefits are often too far in the future and too uncertain.

In Europe the development of the Ariane series of launchers has always been financed by European governments through the European Space Agency (ESA). Only after a successful qualification launch does the commercial operator Arianespace take over, and even then it does not need to pay back the development costs. Developing the original version of the Ariane 5 has cost about $8 billion (in 1996 dollars) and took over 10 years. The revenues obtained from selling Ariane launches are not sufficient to run the operation on a commercial basis and also pay back the initial investments. Because Europe wants to have independent access to space and up-to-date rocket technology, ESAs member states find it worthwhile to finance launcher developments. This is not a typical European situation. In other countries the development of launchers and innovative satellite technology is usually funded by government space agencies or defense organizations (for example, in the United States launcher development is strongly supported by the U.S. Air Force). Scientific space missions are always financed by government space agencies or other nonprofit organizations, because no money can be made on those.

Relatively small space tether projects require modest amounts of money; the financial risks are generally low and development durations relatively short. Projects such as the Small Expendable Deployer System (SEDS) series can be funded as experimental precursor missions, often even by universities. Applications such as the Terminator Tether, for de-orbiting obsolete satellites, may find commercial investors, if the market looks good and the investments and risks are reasonable. However, huge projects such as lunavators and space elevators will cost billions of dollars and take tens of years of development. Moreover, they are technologically and financially risky due to the large numbers of unknowns involved: Do we really understand carbon nanotube ribbon dynamics? What size will the satellite launch market for a space elevator be by the time it becomes operational? How much will it cost to operate and maintain a lunavator? The answers to such questions may require costly research and test programs, or may even not be available before the actual system is put into operation.

Two types of cost are important here: the development cost and the operations cost. The development involves such activities as basic research, test model construction, equipment development, and operations logic development—basically everything needed to make the system operational. The operations cost are those that need to be paid to keep an existing system functioning: maintenance, upgrades, electricity bills, marketing, security services, and so on. Development costs occur only once, while the operations costs recur during the entire lifetime of a system.

Edwards has made some first cost estimates for his space elevator concept. Initially he came up with a total estimate of $40 billion: $20 billion for the "best estimate" plus a 100 percent contingency. In a paper presented in Vancouver in 2004, he and co-author David Raitt were considerably more optimistic. Based on current launch prices, they estimate that it will cost about $1 billion to put the first deployer satellite in space (assembled from individually launched smaller parts). The development of this satellite would cost about $500 million, although this seems to be rather optimistic considering that large, single-launch satellites usually cost well over $1 billion. The production of the not-yet-existing carbon nanotube ribbon is very difficult to estimate at the moment, but Edwards and Raitt's estimate is a total of $390 million for the first space elevator. This number assumes that by the time the construction of the space elevator starts, carbon nanotube fiber production for other applications would already be well established and therefore relatively cheap. Other cost estimates are $370 million for developing and producing the 230 climbers needed to enlarge the space elevator (assuming they are sent up only once, ending their life as part of the countermass), $120 million for an oil rig type of seagoing anchor platform, $1.5 billion for three ocean-going laser power platforms with two lasers each, and $500 million for a space debris tracking radar network. With some $400 million for miscellaneous items and a 30 percent margin on top for risks and unknowns, the total development cost for the first operational space elevator would then be something on the order of $6.2 billion (in 2008 economic conditions).

This is a lot of money, but compared to other large space access investments it is not outrageous. The budget required according to Edwards is even less than the development cost for the first version of the Ariane 5 launcher, while a working space elevator would be incomparably more efficient in launching spacecraft than any conventional rocket. According to

Edwards's estimates, a space elevator would cost even less than the development of large airliners (such as the Boeing 787 Dreamliner, which cost some $10 billion).

It may be better to compare the space elevator's role with large transport infrastructures such as bridges and tunnels. Its development cost is in line with those as well; the almost 4-km-long (2.5-mile-long) Akashi bridge in Japan has cost about $4 billion. The English Channel tunnel linking England with France has cost approximately $13 billion. Even if Edwards's latest estimates for the development of a space elevator are optimistic and the real cost will be considerably higher, the required investments are not prohibitive (assuming that sufficiently strong carbon nanotube tethers can be developed and that there are not other technical difficulties). This means that, at least economically, the space elevator is a much more realistic concept than large space colonies, interstellar spacecraft, and similar grand ideas regularly featured in science fiction.

At the 2008 space elevator conference, Edwards announced an innovative way to fund further space elevator research: he is investigating the feasibility of a combined entertainment and research center, to be called Space Orlando. The entertainment area would involve a 10-story space elevator simulator. Visitors would enter the structure as if they were walking into a real space elevator base station, and then board a climber vehicle for a virtual-reality ascent into space. At the end of the ride up, they would step out into a massive room lined with plasma screens displaying what it would look like to be on a geosynchronous orbit (GEO) space elevator station. Combined with the entertainment facility would be a research center, funded by the tickets sold to Space Orlando visitors, who would also be able to see the research going on at the center. Edwards estimates the facility would cost some $500 million to $1 billion to build and would attract 8 million visitors a year.

In terms of operations cost, to make the space elevator an interesting investment it must provide a way to reduce overall launch costs. Based on the amount and price of the energy needed to bring something up with a space elevator climber and Edwards's estimates of the operations costs of a space elevator, the cost for putting a kilogram of cargo into space could be less than $150. As current launch prices are equivalent to about $15,000 per kilogram (to the geosynchronous transfer orbit [GTO]), at such cost a space elevator would have a huge benefit over conventional rockets.

If the operations costs for a space elevator are indeed a low as predicted, then even the development cost may be recovered. Edwards estimates the cost for keeping the first space elevator going for 10 years to be about $300 million—an average of just over $80,000 per day (this is the indirect operations cost—daily costs that are independent of the amount of payload sent up). Assuming a total development cost of $6.2 billion and a payback period of 30 years, then about half a million per day will need to be recovered in addition to the indirect operations cost. At a projected direct operations cost of just $10 per kilogram payload moved up the space elevator, lifting 5000 kg (11,000 pounds) per day at a fee of $145 per kilogram would be sufficient. That would mean a much larger launch market than today, where 5000 kg is put in space on about a weekly basis rather than every day. However, a space elevator will have an enormous effect on the launch market, enabling a much more intensive use of space due to the unprecedented low launch costs.

The satellite launch market situation represents a vicious circle: the launch market will remain small without breakthroughs such as a space elevator, and for such a small market it does not economically make sense to develop expensive new launch systems. As mentioned before, government investment is probably needed to break this loop and develop the first space elevator. Once it is operational and the launch market increases because of its availability, the construction and operation of additional and improved space elevators may become a purely commercial business. At Earth this stage will be difficult to reach, but for space elevators on the Moon and Mars it will be even harder to find an economical balance between costs and benefits.

Unfortunately, no significant amounts of money have been reserved for space elevator development, or the development of any other large tether application, in the current budgets of the world's space agencies. NASA's current post-shuttle and post-International Space Station plans do not include any important space tether mission, and the space agencies of Europe, Russia, Japan, China, and India also do not see space tether development as a priority.

0 0

Post a comment