Dishwasha (125561) writes "Private space firm Inspiration Mars conducted a press conference today expressing their intention to send a two-person crew to slingshot around Mars in 2018. The plan has been NASA endorsed and the round trip will take around 501 days to complete." Link to Original Source
The first time, it's a KLUDGE! The second, a trick.
Later, it's a well-established technique!
-- Mike Broido, Intermetrics