Thunder and lightning (John Varley)

As Chinese and US spacecraft compete to be the first to land on Mars, a former astronaut, his cousin, and four teens from Florida decide to take matters into their own hands. If they can quickly build their own space-worthy ship using scrap metal, appliances, and power tools, they have a chance to come from behind-thanks to an inventive new power source that can propel them to the Red Planet within three days. No guts, no glory ...