MOSCOW. (Yury Zaitsev for RIA Novosti) - (the following is the continuation of the article published on November 30)
In the last few years, the Space Research Institute has studied the possibility of building a space-elevator cluster that would deliver payloads from the Earth to the Moon and back.
Theoretical studies and experiments showed that the cluster should comprise two cableway systems, one in a low circular and the other in a low elliptical Earth orbit, and one cableway in a circular equatorial lunar orbit. The dimensions of all three cableways should create different gravitational potentials at each end. By adjusting tether length, it will be possible to change each orbital system's angular speed of rotation.
The space-elevator cluster will exchange payloads between orbital cableways. In essence, two-way freight traffic would turn such cableways into a transportation artery.
Most importantly, the system's components would exchange mass and energy. For example, a system in a low circular orbit would act as a sling and place a payload into a higher elliptical orbit, where it would be captured by another cableway. The lower "sling" would then lose part of its energy and move to a lower orbit.
The same would happen when a payload is transferred from a high elliptical orbit to a near-Earth cableway.
The space elevator will thus deliver equipment to the Moon and bring back lunar rock and soil. Its launch frequency, the main criterion of its cost-effective performance, depends on the time needed to restore the "launching" cableway's initial altitude.
The required cable length and rotational speed around the center of gravity will ensure identical trajectories when transferring a payload between lower and upper cableways at predetermined intervals. Reliable grips are needed to prevent dangling during rapid relative movements of payloads and the sling itself.
With this in mind, scientists have suggested an optimal cable-inclination angle in relation to the sling's vertical movement at the link-up point. The payload and the sling grip will therefore remain near each other for considerably longer periods of time.
The Space Research Institute has already conducted several experiments in water and confirmed the main parameters of the projected Earth-Moon-Earth transport system. Calculations show that the new system will weigh 28 times less than the payload it will deliver to the Moon during its entire service life.
Meanwhile, the fuel burned by conventional rocket engines would weigh 16 times more than their payload.
The need to exploit the Moon and Mars will serve as the main incentive for developing space elevators as mankind looks for new places to settle.
Yury Zaitsev is expert at the Space Research Institute, Russian Academy of Sciences