While other kids their age are enjoying time off during spring break, 9-year-old Kimberly Yeung and 11-year-old Rebecca Yeung are busy traveling from their hometown of Seattle to Washington, D.C. to present a project at the annual White House Science Fair.
It's not just any project. The sisters will be exhibiting a homemade "spacecraft" that they created and launched in September.
The Loki Lego Launcher, named for the craft's "crew" of a picture of the family's late cat Loki and a Lego mini figurine of R2-D2, was launched to the stratosphere via a helium weather balloon. It recorded location coordinates, temperature, velocity, and pressure measurements at the edge of space and reported the data back to the sisters on the ground.
"One of the things that we learned from our data was that the temperature gets colder as it goes through the first layer of the atmosphere," Kimberly Yeung told NBC News. "Then it reaches the second layer, the stratosphere, it starts to get a little bit warmer, and then colder again as it goes down."
Prior to being on the White House's radar, the Yeung sisters' project had attracted attention thanks to a video the family made, garnering invitations to visit NASA's Jet Propulsion Lab and Jeff Bezos' Blue Origin space program, among others. The video also attracted the attention of buddingSTEM, a Seattle-based clothing line for girls interested in science and technology. The girls modeled in a photo shoot for the company in the Museum of Flight's Space Shuttle simulator in Seattle last year, and buddingSTEM nominated their project for the White House Science Fair.
"We found out [about the Science Fair] just a few days ago," Kimberly Yeung said. "Just actually being able to go there, it's really special."
Originally, the sisters were planning on launching a second version of the spacecraft with a larger balloon during their spring break, but that'll have to wait.
Last September, the Loki Lego Launcher floated more than 78,000 feet from its launch site in Central Washington. After it burst, the sisters waited until the craft floated back to earth on a parachute. Included on the spacecraft are GoPro cameras, a GPS tracker, a flight computer, a temperature and pressure sensor, the Lego R2-D2 and a picture of Loki. With the cameras attached, the sisters were able to record the spacecraft's flight and even capture Loki and R2-D2 with the Earth's slight curve.
While the spacecraft started as a "family project," most of the work was done by the sisters, they said. Their father, Winston Yeung, assisted in cutting the wood scraps to build the craft and pumping the helium balloon. The sisters did calculations and tests prior to the launch and even have a specific binder to store their notes regarding various models, pre-launch planning, and post-launch data findings.
"Our first version of our spacecraft was made out of PVC pipes but that was too heavy, so we redesigned it to use arrow shafts from some of my bent archery arrows," Rebecca Yeung said in the family video.
But the Loki Lego Launcher isn't the first project the sisters did together. They also created, among other things, a hydraulic arm from a kit they got from the Museum of Flight in Seattle.
"I think the best thing about the project is working together as a family," Kimberly Yeung said.
Science is a favorite subject in school for the sisters. Kimberly Yeung said that when she grows up, she wants to be a robotic engineer with a specialization in bio-robotics to put together prosthetics for medical purposes.
Given their project's momentum, the sisters are already well on their way. On the six-hour car ride home from Central Washington, the two wrote a list of things they learned from the launch, which they posted on their blog.
One of the points, which they reiterated in their video, is fitting: "It's not good to speculate, you always want to rely on data and facts," they said.