“The greenhouse consists of an aircraft-grade aluminum case with a polycarbonate dome, which is curved to prevent to accumulation of dust in the event of a storm, blocks the hard UV radiation from the Sun, and acts as a bioshield to separate the growing area from the outside world. In addition, the experiment also includes pumps for pressurizing the extremely thin Martian atmosphere; filters to keep out dust; a heater; supplies of water, nutrients, and pH balancing chemicals; and a bank of UV lamps.”

Source: www.gizmag.com