Kjell Lindgren has watched three rockets blow up or spin wildly out of control over the past several months, one spectacular failure after another that demonstrated the perils of spaceflight.

Now it’s his turn to fly to the International Space Station for a five-month tour.

So, Astronaut Lindgren: Are you nervous?

Not a bit, it seems.

In interviews with reporters Tuesday morning, he repeatedly said he was excited to fly, eager to experience weightlessness and see Earth from a distance. As for the Russian Soyuz rocket that would fly him to the station, he said he is “confident in the vehicle we are going to fly on.”

[A search for answers after Antares rocket explodes during liftoff]

But despite his scheduled departure being two weeks away, top NASA officials still haven’t given him the official green light, as they work with their Russian counterparts to fully understand what caused a previous flight to go awry two months ago. The officials have said they need to be confident that any problems have been resolved before Lindgren is allowed to fly.

In April, the unmanned Progress 59 mission, carrying cargo to the station, started spinning out of control once it reached orbit. It eventually crashed to Earth, scorched and scattered in pieces.

[Watch an unpiloted Russian spacecraft spin out of control in space]

Official crew photograph of U.S. astronaut Kjell Lindgren (NASA), Flight Engineer with the International Space Station Expedition 44

It was part of a string of recent failures. Last year, an Orbital Sciences Antares rocket blew up seconds after liftoff. Last month, a SpaceX Falcon 9 exploded two minutes into its flight.

[SpaceX’s rocket just exploded. Here’s why that’s such a big deal.]

But those rockets were carrying food, water and supplies — not people.

The mission on July 22 would ferry three astronauts to the station: Lindgren, Sergey Volkov of Russia and Kimiya Yui of Japan.

Last week, the Russians successfully launched the unmanned Progress 60 to the station. It delivered some much-needed supplies on Sunday morning and gave NASA a measure of confidence.

In an interview from Russia's Star City, Lindgren said he is aware that the Russians "have been conducting a very comprehensive review of the Progress mishap, trying to identify the root cause. … We have a couple more flight readiness reviews. We expect that those should go fine.”

He said U.S. and Russian officials were meeting about the investigation on Tuesday and that there are more reviews next week. And while he waits for the official go, he said he’s preparing as if he already has it.

“The posture I’ve adopted is, we’re confident,” he said.

But he added that “flexibility is the name of the game.”

If everything goes as planned, Lindgren, a flight surgeon and father of three, will join the three astronauts already aboard the station. That includes Scott Kelly, the U.S. astronaut who is spending a year in space.