"We'll remember this day for the rest of our lives," Rebecca and Kimberly Yeung wrote in a blog Thursday.

The day was Wednesday and the two girls from Seattle displayed their scientific project along with other science whiz kids at President Barack Obama's final White House Science Fair.

Rebecca, 11, and Kimberly, 9, brought their "Loki Lego Launcher" - a balloon "spacecraft" that they used to launch a photo of their late cat, Loki, to the edge of space.

"That's unbelievable!" Obama told the Chinese-American girls. "You guys are amazing!"

The sisters built the lightweight balloon craft out of plywood, bent archery arrow shafts and rope that floated 70,000 feet above the Earth.

The craft's name - the Loki Lego Launcher - came from two pieces of cargo: a Lego figurine of R2D2 from the movie Star Wars and a picture of their late cat, Loki. There was also a flight computer, a GPS tracker, a temperature and pressure sensor and two GoPro camera.

The Loki Lego Launcher rose to 78,000 feet before the balloon burst on its launch date in September 2015.

The Associated Press reported that after examining the Loki Lego Launcher, Obama said, "But cow poop didn't get on this? You're sure?"

Writing in their blog, the girls said:"We were nervous when he was talking to the other kids, but we weren't nervous when he was talking to us. We got to shake the president's hand. He is really tall, Kimberly had to stretch her neck up to look at him. It was really exciting."

And they added: "We liked it a lot when he said: 'Give me a first bump. I'm proud of you guys.'"

aiheping@chinadaily.com.cn

(China Daily 04/15/2016 page2)