(Image source: NASA)

BY STEVEN SPARKMAN

You're watching multisource science video news analysis from Newsy. 

When the shuttle Atlantis lifts off for the International Space Station, it will be the last flight of the U.S. shuttle program. With no clear successor to the program, it has many asking -- what’s next?

Astronaut Bob Crippen told CNN there doesn’t seem to be a clear answer to that question.

“Truthfully, where we’re at now -- and I’ll tell [NASA administrator Charlie Bolden] this -- it’s not very clear to me... We’re talking about building a capsule, similar to what we used in Apollo. And there’s some talk about a heavy-lift launch vehicle that would allow us to get beyond low-Earth orbit, but it’s not very definitive.” (Video source: CNN)

There was a program meant to pick up where the shuttles left off. President Bush announced a mission for rockets to take astronauts far into space, to be up and running when the shuttles were finally grounded. But astronomer Phil Plait explains in the New York Post -- that program, dubbed Constellation, has fallen by the wayside.

“The project quickly ran behind schedule and over budget. In 2009 President Obama ordered a review, and the results weren’t good: Getting to the Moon and Mars with Constellation would be well beyond any reasonable NASA budget. Obama effectively canceled Constellation.”

That means for the immediate future, U.S. astronauts won’t be going into space in U.S. vehicles. That leaves a bad taste in the mouth of pioneering astronaut and former Senator John Glenn.

“We’ll actually have to go over and have our people go up on the Soyuz, out of Kazakhistan, with Russian launch vehicles. Which I don’t like. I don’t think it’s very seemly for the ‘world’s greatest space faring nation,’ as President Kennedy termed us.” (Video source: CBS News)

But NASA and President Obama are hard at work trying to convince the public that this isn’t the end of manned space flight for America. Losing the shuttles means money can be directed to bigger and better goals.

“We’ll start by sending astronauts to an asteroid for the first time in history. By the mid 2030’s, I believe we can send humans to orbit Mars and return them safely to Earth. And landing on Mars will follow.” (Video source: CBC News)

Under this plan, low-Earth orbit will be left to the private sector. And with several companies planning test flights later this year, these private sector space taxis could be making trips to the International Space Station in just a few years. New Scientist names a few.

“Private companies are well out of the blocks. SpaceX of Hawthorne, California, headed by PayPal co-founder Elon Musk, has been in the spotlight with recent test flights of its Falcon 9 rocket and Dragon space capsule … And it is not the only one. Boeing is working on a crew capsule of its own, called the CST-100, with a view to winning space taxi business...”

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Transcript by Newsy.