how long until humans will have step foot on every planet in our solar system.

Question: how long until humans will have step foot on every planet in our solar system.
- Keywords:
  human,
  planet,
  solar system
Asked by 396enek22 to Shane on 15 Nov 2017.
- Shane Mcdonagh answered on 15 Nov 2017:
  
  This may never happen! The surface of many of the planets are totally inhospitable to humans, for example the surface of Venus is around 462 degrees Celsius. Pluto is no longer considered a planet so the next coldest one is Neptune with a temperature of around -200 degrees Celcius.
  Maybe in the future will will have designed materials and machines that can withstand these extremes…. my guess… not including for how long it would take to get there…. 200 years!

Question: how long until humans will have step foot on every planet in our solar system.