Sunday SpaceX's Crew Dragon Demo-2 Spacecraft is set to arrive back on Earth as it wraps up a historic mission. What began in late May with the first-ever commercial launch of NASA astronauts from U.S. soil to the International Space Station is expected to end uneventfully on Sunday — hopefully.  
"In my opinion, we're only about halfway done, from an engineering standpoint," said
Garrett Reisman, SpaceX Consultant, and former NASA Astronaut. "All the energy we put into the Dragon to get it up into space — the rocket and all that rocket fuel that we turned into velocity — every drop of that energy has to come back out and we have to slow them down and safely bring them to a rest in the ocean." 
Onboard the returning spacecraft will be astronauts Bob Behnken and Doug Hurley. Reinsman, who has been to the ISS, said the men will need time to adjust once they're back on Earth, stating that after he returned "it was tough just to sit up, let alone stand up and walk." 
Reisman also discussed the possibility of Space eventually sending tourists to space at an affordable price. While he concedes a ticket will be out of the reach of most people for some time, he compared it to the price of airline tickets. 
"Keep in mind, when the airlines started, the only people that flew on these initial airline flights, from, say, Burbank to Las Vegas in these rickety old airplanes, were millionaires and movie stars," he said. "Now today we have Southwest and JetBlue and everybody goes. I think we'll follow the same trajectory in space. It just is going to take a while." 
While the landing is scheduled for Sunday afternoon, NASA is closely monitoring the approach of Hurricane Isaias, which could cause the return home to be delayed.