The Pythagoras Sling uses a lengthy graphene string pulled via two hoops suspended from simple parachutes to rapidly accelerate a projectile into orbit. Graphene string will likely become widely available over the next two decades. If it works as expected, the Pythagoras Sling launch system could greatly reduce the cost of getting into space compared to any current rocket-based system and could help accelerate space development. Total cost of the fully reusable launch system could be as low as $1M for small and medium sized satellites so cost per kg could be two orders of magnitude cheaper than today. Apart for human spacecraft or more delicate satellites that need low g-forces, the system needs little or no fuel to achieve orbit, only ground electricity, so would be safer and more environmentally friendly as well as cheaper than current rocket-based approaches.