The desert is not as plain and desolate as one might assume. Its landscapes are versatile and feature sand dunes or vast salt pans. Silent at first sight, the desert teems with unique wildlife. Local fauna features various reptiles including central bearded dragon and sand goanna; mammals such as fat-tailed dunnart and dingoes; feral pests like camels and foxes; and nearly 200 species of birds that typically gather at the temporary lakes that dot the salt pans after downfalls. The rains also bring wildflowers to the desert. Moreover, it's home to the Aboriginal people—the Wangkangurru.
All that wild habitation covers the enormous area of over 170,000 square kilometres stretching on the border between South Australia and Queensland. The Simpson is renowned as Australia's fourth largest desert, and also the world's largest sand dune desert. Needless to explain why crossing it is quite a challenge. It's recommended to explore the Simpson on good four wheels, better even eight—it's safer to go in a company. Cars are to be equipped with fluorescent flags to enhance visibility, and you should also have a CB radio set to Channel 10, a high-frequency (HR) radio or a satellite phone, and some other gadgets necessary for the emergency.
The desert is split into national parks. A yearly Desert Parks Pass is necessary to get access for a vehicle—the fee covers entrance and camping, as well as other useful things such as maps, safety handbooks, etc.
The national parks are normally closed from December 1 to March 15, when the temperature exceeds 50 °C. Nevertheless, for the more updated information, you should check the websites of Australian National Parks. Generally, the access is provided between mid-March and November, still, the most pleasant weather is observed between May and October.