Our visit to Nasa was the highlight of our trip to Houston and would recommend to all.
As older travelers from overseas we enjoyed the Houston City tour but were disappointed in NASA Space Centre. We visited on a Saturday in mid-August, which was still school holidays, so Centre was very crowded. We queued for 1 1/2 hours for red-line train trip and did not see anything that we had not already seen better at Washington Smithsonian Museum and Cape Canaveral. The Centre is designed for children so would not recommend for retired people.
Tour of the city before visiting the Space Centre.Would have liked a bit less time in the city and a bit more at the Space Centre. However, we would certainly recommend this tour.