Tuesday, 16 October 2007
Future Space Ships
The risks from radiation in space, and the need to keep the crew safe on long flights, may influence the shape of future spaceships.
The major radiation sources are galactic cosmic rays, charged particles: from electrons up to the heavy metal elements and 'solar particle events', which throw out protons and helium nuclei.
Exposure from the hazards of severe space radiation in long-duration deep space missions is 'the show stopper'. Protection from the hazards of severe space radiation is of paramount importance to NASA's new vision to reach the Moon, Mars and beyond.
The electrons, protons & heavy-metal ions such as iron and uranium whiz through the void and can all cause cancers. But aluminium shielding capable of staving the radiation off on extended journeys would be prohibitively heavy, burning too much fuel.
The ideal form, according to Ram Tripathi, a spaceflight engineer at NASA, is a grapefruit spiked with cherries on sticks. Positively and negatively charged metal spheres be arranged on struts jutting out of the crew capsule, in carefully controlled directions, to give the crew a high degree of electrostatic radiation cover.
Tripathi calculates the "cherries" would need to be between 10 and 20 metres in diameter and would be stationed about 50 metres from the crew capsule – the "grapefruit". These spheres would protect the crew by deflecting charged particles away from the central habitat. Spheres give you more volume and less mass, and evenly distribute the deflecting charges over their surface.
The spheres would be made of lightweight hollow aluminium, the material shielding the crew capsule would incorporate carbon nanotubes – in a novel composite with aluminium. The nanotubes are light, and they can take a pounding from heavy incoming ions.
Or we could have spaceships with a more conventional shape like a submarine, the starship enterprise, the space shuttle or nerva, with a false skin filled with smaller spheres (or even tubes) having the same desired effect, deflecting radiation and adding volume, without overwhelmingly increasing the mass.
Laser power stations, drawing energy from the local environment, might one day propel spacecraft throughout the solar system. NASA studies of advanced planetary missions have ranged from small robotic probes to multiple-spacecraft human exploration missions.
The completed International Space Station will have a mass of about 1,040,000 pounds. It will measure 356 feet across and 290 feet in length, with almost an acre of solar panels to provide electrical power to six laboratories.
The assembled space station will provide the first lab complex where gravity, a fundamental force on Earth, can be controlled for extended periods. This control of gravity opens up an unimaginable world where almost everything grows differently than on Earth. For example, purer protein crystals can be grown in space than on Earth. By analyzing crystals grown on the ISS, scientists may be able to develop medicines that target particular disease-causing proteins.
Such crystals for research into cancer, diabetes, emphysema and immune disorders grown on the space station have already shown promise. New drugs to fight influenza and post-surgery inflammation are already in clinical trials, and future research will benefit from the extended exposure to weightlessness available on the station.
Many of the changes in the human body that result from space flight mimic those seen on Earth as a result of aging. Understanding of the causes of these changes may lead to the development of countermeasures against bone loss, muscle atrophy, balance disorders and other symptoms common in an aging population.
The Johnson Space Centre, together with scientists and researchers at NASA's other field centers, is working on the technologies that will be required for further exploration of the universe in the next years. For example, a new rocket team at Marshall is developing revolutionary technologies that will make space transportation as safe, reliable and affordable as today's airline transportation.
Hospitals, business parks and solar electric power stations that beam clean, inexpensive energy back to Earth are likely to dot the "space-scape" 40 years from now. Space adventure tourism and travel, orbiting movie studios, and worldwide, two-hour express package delivery also appear just over the horizon.
By 2040, it's expected to cost only tens of dollars per pound to launch humans or cargo to space; today, it costs as much as $10,000 per pound. Bridging that gap requires intense research and technology development focused on accelerating breakthroughs that will serve as keys to open the space frontier for business and pleasure.
Space transportation technology breakthroughs will launch a new age of space exploration, just as the silicon chip revolutionized the computer industry and made desktop computers commonplace.
The New Space Race by Brian Appleyard @ The Sunday Times
The Johnson Space Centre Celebrates 40 Years of Human Space Flight