SpaceX continues to push the envelope on its march to sending manned missions into space.  In the coming months, SpaceX will continue its high visibility tests of the Dragon spaceship in an effort to one day send human into space.

"We have a very aggressive and exciting year ahead of us," says Garrett Reisman, SpaceX's director of crew operations and a former space shuttle astronaut.

Assuming everything goes according to plan, SpaceX believes it will be sending an unmanned Dragon spacecraft to the International Space Station by the end of 2016, followed by an orbital flight with two pilots in early 2017. Development of the Dragon crew capsule, known as the Crew Dragon by SpaceX, began several years ago. SpaceX won its first batch of federal funding for the crew capsule in 2011.

In September, NASA awarded SpaceX with a contract worth up to $2.6 billion to complete its work. The contracts maximum value also includes up to six operational missions to rotate crews on the International Space Station. But SpaceX isn't the only one designing a space capsule.  Boeing is hard at work on a craft of their own known as the CST-100, and NASA awarded the contractor $4.2 billion to complete its worth. 

Both companies are on track to launch astronauts in 2017, when NASA will end its reliance on the Soyuz ferry craft.  But the two companies are taking different approaches to the job.

"We don't want to be pushing on just the schedule because the most important thing is for them to develop their systems in a careful way," says Kathy Leuders, manager of NASA's commercial crew program. "We need to give them enough time to deliver their system as safely as possible."

SpaceX recently completed it's pad abort test, and Boeing is scheduled to conduct a similar test in February 2017, two months before the CST-100's first mission. 

"It (2017) is a busy year," John Elbon, director of Boeing's space exploration division, told reporters earlier this year. "We need to get the capsules ready for launch, so we're following a process that is very similar to the process we followed on the space station, of assigning an individual and a team for each of those vehicles, so they can work in parallel and each of them can be ready. We were launching space station elements once a quarter, and those were each individual spacecraft, in essence, so we're pulling off that experience."

Before the end of the year, SpaceX aims for two more major flight tests. 

"Anytime we do a flight test, we learn a lot," Reisman says. "The sooner you do it, the sooner you can make design changes, and the less painful it is. It's always painful to make changes at the last minute. So testing early and testing often is kind of our mantra at SpaceX, and this falls neatly into that category."

The company plans another demonstration of the Crew Dragon's abort system to prove that the escape rockets will work in flight. 

"There are two points in the trajectory that are the hardest for that system to work," Reisman says. "The first is when it's sitting still on the pad, and we call that a pad abort. When you have zero altitude and zero airspeed, you've got to get high enough and far enough downrange so you can get the parachutes out, get to the water, and get far enough away from any bad thing that might be happening over here (on the pad). That proves that you have enough gas in the tank, essentially."

The in-flight abort test "proves you have enough thrust in the engines to get away and enough controllability in the guidance navigation and control system to get away in a stable manner, even at the most challenging point," Reisman said.

SpaceX's Crew Dragon is an upgrade to the company's Dragon supply ship that is now flying cargo to the International Space Station.  The crew version carries new SuperDraco engines and has a different aerodynamic shape, and SpaceX plans to introduce a new solar panel design, a docking port, updated computers and avionics, a cockpit control panel, seats and a life support system before flying astronauts.