Over the last 60 years, space medicine has primarily focused on effects of microgravity exposure on healthy, professional astronauts. With the advent of low cost, reusable rocketry, space travel will become available to the general public as early as later this year, allowing travellers with underlying medical conditions to be exposed to the space environment. In this project, a lumped parameter computer model of the cardiovascular system will be used to explore the effects of microgravity on travellers with heart failure to quantify the risk of travel and model any countermeasures that could be used.