EDITOR'S NOTE: Over the last year, CNN's John Zarrella has been following mom and NASA Astronaut Cady Coleman as she prepares to launch into space to work on the International Space Station. On Wednesday, Coleman is scheduled to embark on her journey. In her last blog post before lift off, she explains what is racing through her mind as she prepares for her trip. Watch "American Morning" at 6am ET to follow Coleman's progress. Watch the story of Cady Coleman here

Birthday Blog
By Cady Coleman

I’ll keep this short because there are still a few things that I’d like to pack into my last few hours on the planet until next May, not to mention I’m spending as much time as I can with my husband Josh and my sons Josiah and Jamey, before I go. I’m hoping that the photos attached will tell the story of our final few weeks of training before launch.

Who would have thought that it would all happen so fast? This day was always something that would happen sometime in the future… but I find myself in Baikonur, Russia, preparing to launch on a Soyuz for a six-month mission to the International Space Station (ISS), AND I’m turning 50 today. If this is what “Downhill from Here” means – then bring it on!

I thought I knew what getting ready to launch would be like. As a backup for Expedition 24, I watched the prime crew as they completed all the training that precedes a Soyuz launch. I climbed into their spacecraft for a fit check, took all the last classes, got signed off by the medical and training commissions and was pronounced “Certified for Spaceflight”. If my counterpart on the prime crew couldn’t launch for some reason, then I would go in their place.

Now I’m finding that everything feels different when you are really the NEXT crew to launch. I realize that the prime crew always had a look in their eyes – a kind of wonder and anticipation that can’t be felt by the backups. Not many people get to leave our planet in a spacecraft bound for the International Space Station – and Dmitry Kondratev, Paolo Nespoli and I, the crew of Soyuz TMA 20, are launching in less than 24 hours!

Two weeks ago we flew to Baikonur, Kazakhstan to complete the last phase of our training. We are in quarantine at the Cosmonaut Hotel here. That means that we can’t see anyone who hasn’t had a physical, and we can’t leave. Three great meals a day, it is a cross between prison and paradise! Even family have limited access, which is probably the hardest part of the last few weeks. I’ve tried to put that aside as we completed a busy series of fit checks in the REAL Soyuz and some final classes to review the important points of launching and then working aboard the ISS.

Our families and the backup crew got to watch OUR VERY OWN SOYUZ taken by train out to the launch pad and placed upright in the launch position. Josh likes to joke that arranging a ride to space in the Soyuz was the least he could do for my birthday present!

I look forward to sharing our 5 month mission with you. The steps that Gagarin took just 50 years ago were huge. Who knows what new first steps will result from our work aboard the ISS? I’m proud to be a part of the space program and I look forward to sharing our mission. I’ll sign off for now with launch less than a day away.

As Yuri Gagarin would say, “Поехали!” or “Let’s GO!”