LONGUEUIL, Que. -- Canadian astronaut David Saint-Jacques boarded the International Space Station Monday afternoon, declaring himself "astounded" by the journey and excited for the discoveries ahead of him.

After the hatch opened at 2:37 p.m. Eastern, Saint-Jacques and his two crewmates floated in from the docked Soyuz capsule, embracing the astronauts who have been at the space station since June.

"I am completely astounded by everything I have seen," Saint-Jacques said during a brief conversation with family members on the ground at the Baikonur Cosmodrome launch site in Kazakhstan.

Speaking in French, he described his first sunrise seen from space as "breathtaking." He said "it's just the beginning" of the discoveries ahead of him.

Canadian Space Agency president Sylvain Laporte told the crew members there was "a lot of relief" when the astronauts entered the space station.

"Although we knew that you were safe and sound, there was nothing like seeing you come through the hatch," Laporte said.

The Soyuz MS-11 space capsule had reached the space station about two hours earlier. "Good contact, and capture," a commentator said on NASA television as the capsule docked six hours after blasting off.

The launch of the spacecraft carrying Saint-Jacques, Anne McClain of NASA and Oleg Kononenko of the Russian space agency, Roscosmos, appeared to go exactly as planned, lifting off at precisely 6:31 a.m. Eastern.

"We have liftoff," a NASA television commentator said as the rocket roared into the sky under 930 pounds of thrust and at a speed of 1,770 kilometres per hour. "Everything looking good, vehicle is stable -- good first stage performance."

The crew reported that all went well in the critical initial minutes after liftoff.

Back on Canadian soil, a crowd monitored the launch from the Canadian Space Agency in Longueuil, Que., as the rocket began its trip to the space station.

Innovation Minister Navdeep Bains praised the successful takeoff and said the mission offers an exciting opportunity for scientific research and developments that could have broad applications, in such things as robotics and aging.

"Space represents a lot of opportunities for a lot of Canadians," he said at the agency office. "It really is inspirational what David represents...today is an incredible day in space."

Astronaut Jenni Sidey-Gibbons echoed the message, saying Saint-Jacques was a special role model for her and other young people who may be considering a future in space.

"That was particularly important for me when I was growing up and I certainly wouldn't be where I am today if it wasn't for Canada's early space program and, kind of, the heroes that pushed that forward," she said. "It's incredible."

It was the first manned Russian rocket launch since a dramatic aborted Soyuz mission in October.

On Oct. 11, a rocket failure forced a Soyuz capsule carrying two astronauts to make an emergency landing.

Russia suspended all manned space launches pending an investigation before giving the green light Nov. 1.

Saint-Jacques, 48, has spent years training for the six-month mission, which was originally scheduled for Dec. 20 but was moved up after the aborted Soyuz launch.

Aboard the station, he will conduct a number of science experiments, with some focusing on the physical effects of the weak gravity astronauts experience in orbit.

Former astronaut Robert Thirsk said the schedule will be especially busy for the trio.

"Every five-minute increment of our life is scheduled, and that will be the same for David also," he said at the space agency office. "The challenge for him will be to pace himself to accomplish the work that's expected of him."

The arrival of the three astronauts restores the space station's crew to six as they join Serena Aunon-Chancellor of NASA, Alexander Gerst of the European Space Agency and Sergey Prokopyev of Roscosmos, who are scheduled to remain aboard until Dec. 20.

The crowd watching the liftoff in Kazakhstan included members of Saint-Jacques' family as well as Gov. Gen. Julie Payette, herself a former astronaut.

Payette, who completed missions to the space station in 1999 and 2009, had said the most dangerous moments come immediately following the launch as the rocket passes through several "critical zones" on its way into space.

The last Canadian astronaut to visit the space station was Chris Hadfield, who was on a five-month mission that ended in May 2013.