Red Planet Mars Life
Lawrence M. Krauss’s “Rethinking the Dream” [Forum] rightly points out that the benefits of flying humans in space have not been commensurate with the cost, especially when human flight is compared with advanced robotic or automatic systems that can do many of the same tasks at one tenth of the cost and with no risk to humans. I think this is a result of nasa’s focus on dramatic, exciting exploration and failure to create an economical, durable infrastructure. I disagree with Krauss only where he advocates one-way missions to Mars. I believe that keeping humans alive on the planet for more than a few weeks will be extremely costly.

The Martian atmosphere is very thin and contains essentially no oxygen. The average surface temperature is about –60 degrees Celsius. Humans must always be in a pressurized enclosure, with a suitable atmosphere and adequate temperature and humidity control. Unlike Earth, Mars does not have a protective magnetic field, and the thin atmosphere provides little shielding from cosmic rays. I suspect some rather heavy shielding will have to be included in any habitats, rovers, and so on. Living off the land is, I think, absolutely ruled out on Mars, where there is no free water and what water ice there is seems to lie below the surface. To be of use, it would have to be collected, thawed and purified.

NASA has learned that an average human will require about five kilograms of food, water and oxygen each day and will produce an equal amount of waste. Of course, water can be recycled, oxygen can be extracted from CO2 and solid waste can be treated, but all that requires power and equipment. Solar arrays on Mars must be twice the size of Earth arrays because solar radiation is weaker (the planet is farther away from the sun). And the arrays will likely require cleaning from Martian dust. For safety reasons, there must also be redundant equipment, plus tools and spare parts for repair. Solid food cannot be recycled, and growing food would require a large, totally enclosed “hothouse.”

The habitat must have air locks to enable humans and their rovers to get in and out without depressurizing the entire living environment. Surface excursions must not go so far from the habitat that participants will not be able to walk back in case their rover breaks down. Furthermore, if a sortie lasts longer than a few hours, the rover must provide food, water and toilet facilities.

Finally, there are human considerations that do not factor directly into costs but that I think make the whole idea unfeasible. Will the colonial-nauts include a doctor? Will the habitat include clinical/hospital facilities? What about recreation? What about normal family life? What happens when the colonial-nauts age and die?

Most of all, why would anyone go?
Don Peterson
Retired U.S. Air Force pilot and NASA astronaut
El Lago, Tex.

COCKTAIL PARTY CHATTER
I am deaf in one ear, and even though my hearing is much better than most, I experience the issues described in Graham P. Collins’s “Solving the Cocktail Party Problem” every day. For me, it is only when a room is very noisy and I am struggling to comprehend the conversation that I notice the process I use to solve the cocktail party problem. My technique seems to be a combination of those mentioned in the article. As in spread-spectrum signal processing, once I know what a person sounds like, I listen for the sounds he or she is making. Second, I take in the sounds and try to reconstruct the words based on the expected probability of sounds surrounding each one. Finally, I use the probability of words surrounding each one based on the context to fill in the sentence. I knit the sounds into words and the words into a sentence.

This procedure is imprecise and adds a time delay. It is very common for me to knit a sentence together several seconds after everyone else heard it. Everyone laughs, and seconds later I get to “hear” the punch line in my head. Having to do all this processing does have an upside. Sometimes the combination of words that my mind has rejected sounds like what was said and has a message that is related to the topic but creates an absurd vision in my head. Periodically the incorrect interpretation of the sounds is more entertaining than what was actually said.
Kee Nethery
Berkeley, Calif.

BIOTECH FOOD AND DRUGS
Both Brendan Borrell’s interview with agro-research czar Roger Beachy [“Food Fight”] and Mary McKenna’s “The Enemy Within” point to a serious disconnect between research, learning and hopes for applications of that research. Beachy says that crops with permanent resistance to pests are “almost unheard of,” and McKenna shows us how scary the future of infection may be with antibiotic-resistant bacteria winning over the development of new medicines. There is no difference between the loss of valuable antibiotics to ever more resistant bacteria and the fight with pests through genetic engineering. In only a few years, with the planet’s food-production capability more strained by population demands, major crop harvests may well follow the same hazardous, on-the-edge life we humans are walking ourselves into as a result of not learning our lessons from history nor from one another.
Scott C. Reuman
Nederland, Colo.

FAMILY ALBUMS OF THE FUTURE
David Pogue laments in “Seeing Forever” [TechnoFiles] that current digital media may not last long. And it is good that in 100 years 99.9 percent of all images, video and audio recordings will be gone. Who cares about Uncle Joe’s photos from his 2005 vacation in Florida or Italy? Future generations need their own memories plus the very best from past generations. Nobody in the year 2100 will have the time to look at pictures from their forebears of the past 100 years. They need to build their own memories.
Marc Tomaszewski
Friedrichshafen, Germany

LIVING DREAM
Eitan Haddok’s “Can the Dead Sea Live?” shows how pragmatism can give hope.
A project involving salvation of an extraordinary body of water brings together three politically disparate regions: ­Israel, Jordan and the Palestinian Authority. It is a rare example of cooperation in the midst of a bitter area of human conflict. An organization that has been monitoring the project, Friends of the Earth Middle East, consists of participants from each of those regions. The organization, and specifically its undertaking to save the Dead Sea, is a wonderful example of how the effort to save a precious resource can raise people above endless, vicious political squabbling.
Stanley P. Santire
Houston