MESSENGER Webcast: MESSENGER Mission Overview
NASA Direct! Presents: A Look At NASA's Launch Services Program

Five, four, three, two, one, start and liftoff! Why do we send anything into space? Well, it turns out sending spacecraft into space has a major impact on your life, and in ways you may not have realized. Hi, I'm George Diller, a NASA launch commentator.

You're starting on a fascinating tour behind the scenes of NASA's Launch Services Program. Have you ever wondered how you can receive television shows through a household satellite dish? Or, how we're able to monitor the weather and other forces at work on Earth? And how much effort did it really take to get the Mars Exploration Rovers Spirit and Opportunity safely to the red planet?

None of this happens overnight. Every mission is a product of months, often even years of challenging work. Every spacecraft must be designed, developed, built, tested and prepared for launch, and finally shipped to the launch site -- either Cape Canaveral Air Force Station in Florida or Vandenberg Air Force Base in California.

How do these engineering marvels get to the launch site? And once they get there, who puts on the finishing touches to prepare the spacecraft for flight? Spacecraft are shipped either fully put together, or in sections. They arrive on planes, trains, even boats. They they're taken into a processing facility where engineers get them ready for launch. The processing facility is a cleanroom environment, but in the space business, the cleanroom goes a lot further than putting things away and making the bed.

Everyone working on the spacecraft has to put on a special suit, affectionately known as a "bunny suit," over their own clothing. They have to tape their jewelry to their skin to keep it from getting loose in the work area, cover their beards and tie a string around their glasses so they don’t accidentally come off.

It sounds extreme, but there's a good reason: They need to keep the spacecraft and its delicate parts as clean and as bacteria-free as possible. When the spacecraft is finally ready for launch, it starts the last leg of its journey on Earth. It's taken to the launch pad, where it is added to the launch vehicle.

NASA's Launch Services Program, operating from the Kennedy Space Center in Florida, uses many types of space vehicles. They choose the type of rocket that is best suited to the weight and the destination of the spacecraft and the mission's goals. Most rockets lift off vertically; most of us have seen rockets that sit on a launch pad. When the countdown clock gets to zero, the engines ignite and send the rocket on its way.

But there's also another more unusual type of rocket. It's small enough to attach to the underside of a commercial airplane. The airplane flies to just the right place and the right altitude, then drops the rocket, which lights its own engine and sends the spacecraft into space.

As you can see, launching a space mission is no small job. It takes a lot of time and care to make sure that each and every spacecraft and launch vehicle is ready for the flight. But these missions help us live safer and healthier lives, and that makes everything worth it.