The space shuttle Columbia illuminates a cloud during a morning liftoff. (Anita Barrett/AP)

There’s a 70 percent chance that Friday’s shuttle launch will be a no-go. But when the skies do clear, NASA will send its last shuttle into space. For 30 years, space shuttles launching into the sky and returning home have captured the nation’s imagination.

I remember: the texture of Neapolitan-flavored ice cream from the Air and Space Museum, freeze-dried in a silver package — just like the astronauts ate it.

I remember: my sister’s tears. Her science teacher, Mr. Wollitz, had come close to winning a contest: the first teacher in space. It seemed like all of Fuerte Elementary came out to watch the woman who beat him board the Challenger. I don’t remember much, but I remember my sister’s tears.

Astronaut Shannon Lucid in Sept. 19, 1996. (AP)

After the launch, the shuttles will move to museums, launching only in our memories. Thousands will be out of a job as the shuttle program shutters. Astronauts face an uncertain future. The space station may be endangered by the shuttle program’s end, one past flight director worries, but as Joel Achenbach writes, “that horse done left the barn, folks.”

There will be plenty of time to look forward. The end of the shuttle program does not mean the end of NASA. Far from it, with the space agency now setting its sights on a human landing on Mars. Yet its a good time, still, to pause and look back over the missions and moments that stand out, writ large on our collective memory. Check out the gallery of the space shuttle from1981-2011. And share your memory here with us.

YOUR TAKE: #NASAmemories

Tweet We asked what NASA means to you? And you replied with a few of your #NASAmemories. These are a few of the responses:

Reader Bromisky writes: “I'll always remember that first shuttle flight flown by John Young and Robert Crippen. It was John Young's reaction after touching down; bouncing around, slapping hands with everyone in sight, it was as the space age had started all over again. I remember my childhood in the sixties was dominated by watching every spacelaunch with my family, and since my father was an Aerospace Engineer, we had a running commentary with every broadcast. We had everything in front of us, now, it's all over.”

I will always remember the sonic boom in the Tehachapi Mtns as the shuttle went overhead @nasa #LOVEYOU #NASAmemories than a minute ago via Tweet Button Favorite Retweet ReplyBRADLEYIFV™

Listening to the moon landing on the radio of a pickup alongside a dirt road ‘cause we were 50 miles from the nearest TV. #nasamemoriesless than a minute ago via TweetDeck Favorite Retweet ReplyAbby Jensen

#NASAmemories I saw video of the Apollo 11 landing on the moon at age six or so on PBS. Was enthralled and got astronomy books same day.less than a minute ago via TweetDeck Favorite Retweet Replykc

Making a model of Space Station Freedom using the school cafeteria’s milk straws & pipe cleaners for #YoungAstronauts club. #NASAmemoriesless than a minute ago via TweetDeck Favorite Retweet Replycchen7

My fifth grade teacher taught her entire curriculum around the space program and ever since I’ve been a NASA junkie #NASAMemoriesless than a minute ago via web Favorite Retweet ReplyHana Rouse

Watch astronauts reflect on their time in NASA: