The need for broadband communications with manned Moon and Mars missions is under discussion by the major space agencies because of potential problems with frequency availability. Video may have to be transmitted from Earth to crewed spacecraft by the end of the next decade and will require low-band frequencies already allocated to terrestrial users.

The space agencies want to lobby the World Radio Conference (WRC), expected in 2011 or 2012, to allow new allocations to enable the broadband uplinks required. Held every three or four years, the WRC is the only opportunity to change frequency allocations under the International Telecommunications Union (ITU), which regulates frequency use for satellites and other spacecraft out to a distance of 1 million km (621,000 miles) from Earth, the legal definition of deep space. The Moon is only 385,000km from the Earth.

Space agencies have had two meetings this year to discuss the issue. “Optical communications using lasers would be a solution [the ITU does not regulate laser communication], but the technology is not there yet,” says Eduardo Marelli, the European Space Agency’s head of frequency management.

Source: Flight International