High Frontier can help Mars Direct

In a message dated 5/12/01 3:36:54 PM Eastern Daylight Time, jhuebn@...
writes:

<< There are other issues for a "plastic wrap" garden on Mars. Mars has no
oxygen in its atmosphere and so no ozone protection from the hard solar
ultra-violet radiation. Plastic left outside on Earth breaks down in a few
months or years from the soft ultra-violet which gets through our ozone
layer. Exposed plastic wrap would rapidly be destroyed on Mars.
>>

Some plastics may degrade faster than others. The plastics we use on Mars
don't have to last for all of eternity, they only have to last long enough to
grow plants. There is no short supply of glass on Mars either. I had a
plastic greenhouse once and had to replace the plastic every year.