Good news for future human settlement of Mars: a supply of water for Mars colonists will not be a problem.
AUSTIN, Texas—Vast Martian glaciers of water ice under protective blankets of rocky debris persist today at much lower latitudes than any ice previously identified on Mars, says new research using ground-penetrating radar on NASA's Mars Reconnaissance Orbiter.
Because water is one of the primary requirements for life as we know it, finding large new reservoirs of frozen water on Mars is an encouraging sign for scientists searching for life beyond Earth.
The concealed glaciers extend for tens of miles from edges of mountains or cliffs and are up to one-half mile thick. A layer of rocky debris covering the ice may have preserved the glaciers as remnants from an ice sheet covering middle latitudes during a past ice age.
"Altogether, these glaciers almost certainly represent the largest reservoir of water ice on Mars that's not in the polar caps. Just one of the features we examined is three times larger than the city of Los Angeles, and up to one-half-mile thick, and there are many more," said John W. Holt of The University of Texas at Austin's Jackson School of Geosciences, lead author of a report on the radar observations in the Nov. 21 issue of the journal Science.
"In addition to their scientific value, they could be a source of water to support future exploration of Mars," said Holt.
So would it be better to melt all that ice? Some of the water would evaporate into the atmosphere providing Mars with a higher atmospheric pressure. But it is not clear to me that would help. The amount of radiation reaching the surface would probably still be so high that underground colonies would continue to make the most sense. If the water is kept frozen then colonies could be located around glaciers and only melt as much water as needed.
To make Mars a full outside-living planet where can the oxygen come from? The outer planets seem to have little oxygen. Can anyone point to abundant sources of oxygen in this solar system outside of the Earth? The Mars glaciers are mostly oxygen since water is made from 2 hydrogens and an oxygen. But I doubt enough oxygen is in that water to support a high atmospheric pressure.
Neptune's moon Triton seems like the best place to go (leaving aside energy costs and time) to get oxygen and nitrogen for a Mars atmosphere. We could remove Triton's surface and transport it to Mars for the nitrogen and oxygen.
As with Pluto, 55% of Triton's surface is covered with frozen nitrogen, with water ice comprising 15–35% and dry ice (frozen carbon dioxide) forming the remaining 10–20%.
But does anyone know how much mass of nitrogen and oxygen are on Triton as compared to how much would be needed to give Mars an atmospheric pressure similar to that of Earth?
Or does anyone have a good source for how else enough oxygen and nitrogen could be found to make the Mars atmosphere capable of supporting humans outside?
Update: James Bowery points me to a problematic report on why Mars lost its atmosphere in the first place. David Brain of UC Berkeley says irregular magnetic fields on Mars cause pieces of the Martian atmosphere to pinch off and get blown away by the solar wind.
Brain was scrolling through archival data from Global Surveyor's particles and fields sensors. "We have measurements from 25,000 orbits," he says. During one of those orbits, MGS passed through the top of a magnetic umbrella. Brain noticed that the umbrella's magnetic field had linked up with the magnetic field in the solar wind. Physicists call this "magnetic reconnection." What happened next is not 100% certain, but Global Surveyor's readings are consistent with the following scenario: "The joined fields wrapped themselves around a packet of gas at the top of the Martian atmosphere, forming a magnetic capsule a thousand kilometers wide with ionized air trapped inside," says Brain. "Solar wind pressure caused the capsule to 'pinch off' and it blew away, taking its cargo of air with it." Brain has since found a dozen more examples. The magnetic capsules or "plasmoids" tend to blow over the south pole of Mars, mainly because most of the umbrellas are located in Mars' southern hemisphere.
So how can we create a strong consistent magnetic field on Mars capable of retaining an atmosphere for a long time? Bring iron in from elsewhere in the solar system? If so, where?
|Share |||Randall Parker, 2008 November 22 07:16 PM Space Exploration|