And what if you want to go up into space yourself? When do those space tourism flights start booking?
NASA says yes -- it is going deep into space to visit Mars. It's building a new spaceship and a powerful rocket to help land people on Mars by the 2030s.
And if you want to make a space trip yourself -- not to Mars, but maybe a suborbital or low-Earth orbit flight -- there soon may be lots of options.
Wait. What's a suborbital flight? How high is low-Earth orbit? How deep is deep space?
OK, let's take a moment to review a little space lingo:
-- Suborbital: According to NASA, this region of space is between 62 miles (100 kilometers) and 85 miles (137 km) above Earth. If you took this type of flight, you wouldn't ever go into orbit. This is the slice of space where many space tourism companies plan to operate.
-- Low-Earth orbit: If you're spaceship takes you up between 85 miles (137 km) and 2,000 miles (3,219 km) in altitude and then goes into orbit around the Earth, you are in a low-Earth orbit, according to NASA. This is where the space station and many scientific satellites orbit.
-- Deep space: NASA defines deep space as anything beyond the orbit of the moon, which is more than 300,000 miles (482,803 km) from Earth.
Mission to Mars
Deep space has special challenges for humans, but NASA still plans to go.
"Yes, NASA is on a journey to send humans to Mars! Our robotic scientific explorers are already there paving the way," said Jim Free, a deputy associate administrator in NASA's Human Exploration and Operations Mission Directorate, told CNN Digital in an email interview.
Mars is about 140 million miles (225 million km) away. It will take at least nine months to get there and a round trip could take up to three years.
This means NASA needs lots of new equipment. The agency is building a powerful rocket called the Space Launch System (SLS) that will carry its new Orion spacecraft into deep space.
The SLS is expected to be ready for Orion's next big test flight in 2018. (The first test flight used a United Launch Alliance Delta IV Heavy rocket). And SLS will launch Orion on its first crewed test flight in 2013.
Orion looks like the old Apollo command modules -- the ones that brought the astronauts back to Earth after the missions to the moon in the late '60s and early '70s. But it's bigger. Orion has 316 cubic feet of habitable space compared with 210 cubic feet for Apollo. And it's much different inside.
It has room for up to six crew members on short flights, Mark Geyer, deputy director of NASA's Johnson Space Center in Houston, told CNN's Rachel Crane. (Only three astronauts could fit in Apollo.) And it will be able to carry four people on longer flights of about 21 days. The seats would be put down after liftoff to make more room, Geyer said.
There's even a toilet. That may sound basic, but it's a huge improvement over Apollo's "waste management system." Even with a powerful rocket and a new spaceship, Mars still is a nine month trip. Surely NASA doesn't plan to keep four people locked up inside Orion for that long!
"No, no, no, no," Geyer said. "You'd drive yourselves crazy."
OK. So what gives? How does the crew get a roomier ride to Mars? And where will they live when they get there?
NASA's still working on that. Orion "will need to be augmented by in-space and on-Mars habitation modules, as well as a Mars lander," Free told CNN.
Obviously a big mission like the journey to Mars has its critics. The Aerospace Safety Advisory Panel, which was established by Congress in 1968 to make recommendations to NASA on safety, chided the agency for not having enough detail in its "detailed outline" for the journey to Mars.
Even NASA legend Kris Kraft has spoken out against the SLS. In 2013, Kraft, the first U.S. human space mission flight director, told the Houston Chronicle that SLS is too expensive.
"When they actually start to develop it, the budget is going to go haywire," he said.
Kraft added that he expects technical issues to drive up costs as the rocket is being developed. "Then there are the operating costs of that beast, which will eat NASA alive if they get there," he said.
But NASA Administrator Charles Bolden insists the mission is happening and repeatedly mentioned the mission in his annual State of NASA address in February.
"Because we are closer today than ever before in human history to sending American astronauts to the Red Planet ... the state of our NASA is strong," Bolden said.
Space tourism
OK, it will be more than a decade before the Mars mission happens, and NASA still has lots of work to do.
What if you want to take your own spaceflight?
If you have lots of money, you can book a flight right now on a Russian Soyuz rocket for a stay in low-Earth orbit on the International Space Station. The first space tourist, Dennis Tito, flew a Soyuz to the space station on April 28, 2001. He reportedly spent $20 million to spend six days on the station.
A company called Space Adventures is still booking flights on the Soyuz and is the only company actually sending private citizens to space. Today's cost? About $35 million.
There could eventually be more options for space tourists. Several private companies are planning to offer suborbital and orbital flights. Here are a few:
Richard Branson's Virgin Galactic unveiled a new space plane in February. The company won't be taking up passengers though until the plane has had extensive testing. Eventually, it will take tourists about 62 miles (100 km) above the ground, earning them their astronaut wings.
SpaceX has used its Dragon spacecraft to deliver several loads of cargo to the space station. The company has a contract with NASA to send astronauts to the space station but says its ultimate goal is enable people to live on other planets.
Boeing also has a contract to send astronauts to the space station in the future on its CST-100. And the company says it's working with Bigelow Aerospace and Space Adventures "to advance space tourism." Bigelow is testing inflatable space habitats and plans to put a hotel in low-Earth orbit.
Blue Origin is planning to offer suborbital flights, or what it calls the "astronaut experience." Passengers would go about 62 miles (100 km) above the ground.
The United States isn't the only country looking to put more people into space. China plans to send a second space lab into low-Earth orbit and hopes to have a full space station operational by 2020.
So within a few decades, we may have several ways to get way up above Earth. And, if NASA's plan stays on track, we may even have people in deep space on Mars.
