Eleven companies submit ideas for launchers, vehicles, space stations and bases
Plans to return to the Moon and stay for weeks at a time were presented to NASA late last month when 11 companies outlined their ideas on launcher choices, crew exploration vehicle (CEV) capabilities, Lagrange point space stations and Moon base options.
Launcher options ranged from rockets capable of placing between 40t and 70t into low Earth orbit (LEO) to Space Shuttle-derived vehicles capable of lifting 100t-plus. Such vehicles will all have to be developed from scratch, because the largest available US launcher is the 23t-to-LEO Boeing Delta IV Heavy, which has yet to fly.
The crew exploration vehicle would carry four astronauts either directly to the Moon or to an L1 Lagrange point facility (where the Earth's gravitational pull equals that of the Moon). Companies are focusing on a four-man CEV because five- or six-person crews would lead to prohibitive costs and technical issues. The L1 facility could comprise one or two Mir-like modules and provide fuel and spares. It could also be used as the location for assembly and launch of a Mars ship. At the L1 facility, a lunar lander would dock with the CEV and take astronauts to the Moon base. However, L1 could be used just as a waypoint for crew transfer.
Once in lunar orbit, detailed topographical terrain maps would be used for accurate landings. A lunar equivalent of the global positioning system is deemed too costly because of the need for a GPS-like satellite constellation.
The preferred landing sites for bases are the equator and south polar region. For the first manned mission in late 2014, Boeing is proposing a 20t habitation module that would be sent to the equator months before the astronauts arrive to test its reliability. The module could be home to four astronauts for weeks at a time. The company also envisages a lunar base "build-up" from 2017 to 2019, with crews potentially expanding to up to eight people. Lockheed Martin is proposing a main base at the equator from which astronauts would launch robot rovers to explore the lunar surface. This would save on the energy required to send astronauts on long excursions away from the base.
The Moon bases could use nuclear or solar power or a combination of both. Nuclear power would be required for in-situ propellant and oxygen production by baking lunar rock. Based on experience with the International Space Station, the lunar base would require a single yearly supply delivery, which could be achieved with one 20t-to-LEO launch vehicle. A waste dump would also be needed because waste could not be returned to Earth's atmosphere to burn up.
Using the Moon for rehearsing elements of a Mars mission is a popular recommendation. The L1-to-Moon transfer is seen as a way of practising a Phobos-Martian surface transit, because both require the same amount of energy, according to Seattle-based Andrews Space. This is a consideration because Phobos could be a natural space station for a Mars mission.
This company is also urging NASA to commercialise cargo and tourism aspects of the new exploration effort. Other companies also recommended the space agency should sell access to the US-Earth-L1-lunar logistical chain to other space agencies, for example Russia's.
Some companies have costed the missions to try to make sure they are affordable under the NASA budget proposed by President George Bush at the launch of his space exploration initiative.
NASA's Exploration Systems Mission directorate awarded the 11 companies six-month contracts worth $1-3 million in September. Boeing, Lockheed Martin, Northrop Grumman, Andrews Space, T-Space, Shafer, Draper Labs and Orbital Sciences are conducting concept exploration and refinement studies for human lunar exploration and the crew exploration vehicle.
The US Congressional Budget Office (CBO) says a return to the Moon will cost $100 billion, more than double NASA's estimate. The CBO says it will cost NASA about $64 billion for the initial manned Moon mission, but this does not include $29 billion for robotic precursor missions, writes Tim Furniss. The office suggests a 2016 return to the Moon target could be met by grounding the Space Shuttle in 2005 and leaving what exists of the International Space Station (ISS) to the partners. But the CBO says it might be better to keep the Shuttle flying, finish the ISS and delay the Moon flights.ROB COPPINGER / LONDON
Source: Flight International
