The second expedition to Mars arrives in the year 2000, but crew are wearing flag patches with only 48 stars.
When the second expedition lands on the alien grass, there should be scorch marks from the rocket's boosters from landing - but there are none.
On the night of the farewell party for Colonel Wilder (set in the summer of 2001), all of the cars driving by the club are clearly from the 1970s.
Though set in the near future, the astronauts' shoulder patches show pre-1960 48-star American flags.
Colonel Wilder refers to the first mission as a trip to the outer planets. Mars is an inner planet (the divide is the asteroid belt).