July 24, 2013
BBC Program Asks “How Do We Get To Mars?”
Brett Smith for redOrbit.com - Your Universe Online
This weekend, BBC News and Imperial College London will treat BBC viewers to a five-part television series depicting how a manned mission to Mars might unfold.
According to BBC News, the program is intended to stoke the conversation about the risks and obstacles that such a mission would entail.
"Every part of this mission scenario has been demonstrated one way or the other, including the in situ propellant production on the surface of Mars," Imperial professor Tom Pike told the British news agency. "There are big, big jumps between a demonstration at one level and putting together the engineering systems for a mission, but they are engineering challenges. They are not fundamentally about making new discoveries."
According to the documentary, the manned mission would begin with a rocket launch sending a two-part craft into Earth orbit just as Mars is approaching its closest distance to our planet. A rocket burst would then send the craft on a curved trajectory toward Mars.
After leaving Earth's orbit, the two parts of the craft, the lander and the cruise vehicle, would extend from each other via an unwinding steel cable. Tethered by a distance of about 200 feet, short thruster rockets would send both sections spinning around a central pivot point to create artificial gravity through centrifugal force. This faux gravitational pull would prevent 1 to 2 percent bone loss per month caused by the microgravity of outer space.
As the craft approaches Mars, the spin rate would be slowed from an approximation of Earth's gravity to an approximation of gravity on Mars.
"We've obviously got some real issues with a long-term mission in terms of the de-conditioning which goes on in the space environment," said Ryan Robinson, a physiologist from Imperial. "If (crew member are) landing they'll be susceptible to fractures if they've got to be exerting themselves."
Astronauts would also be exposed to deadly solar flares and cosmic radiation throughout the entire Mars mission and steps would need to be taken to limit or prevent exposure, the scientists said.
After landing on the Martian surface, the crew would be able to perform experiments and make observation not yet possible with robotic explorers.
"Some people think that the use of humans is just something that is popular and attractive from an adventure and inspirational point of view, but there are also real scientific benefits for sending humans," said Mark Sephton, the Imperial team's geologist. "Humans can data process while they're walking around, while they're looking at rocks. They're probably the most sophisticated computer, the most sophisticated robotic living organism that we can imagine."
While getting to and surviving on Mars is challenging enough, the scientists involved in the show said the biggest difficulty would be getting Martian explorers back home. Rocket fuel would have to be generated by mining frozen water from the Martian surface so that it could be split into hydrogen and oxygen, both necessary components for fuel. To accomplish this, the scientists said an automated mining and production facility could be launched in advance on the manned mission.
With enough fuel waiting for them on the Martian surface, the crew could launch a craft to rejoin the orbiting cruise vessel. The rejoined vessel could then begin the nine-month trek back home.
While the entire project sounds a bit like science fiction from the "not too distant future," several recent private proposals have envisioned sending people to Mars in the coming decades.