Attendance for NASA's Jet Propulsion Laboratory Open House in La Cañada was so astronomical on Saturday that officials closed the event off to new entries just a few hours after its start.
JPL officials had previously said it wasn't unusual for up to 20,000 guests per day to visit for the free annual event, held both Saturday and Sunday, but that estimate skyrocketed this past weekend.
"JPL Open House is at capacity for vehicles & walk-ins for the remainder of today. The entrance is now closed," JPL posted to Twitter just after 12:15 p.m. Saturday. The event was scheduled to run from 9 a.m. to 4 p.m.
Sunday saw a similar situation, with officials first announcing they were at capacity just before 10:30 a.m. — just 90 minutes after opening.
Approximately 45,000 people total attended the weekend event, according to JPL spokesman Preston Dyches, not including the many would-be visitors turned away at the gate after JPL reached its capacity.
Traffic on the 210 Freeway and Oak Grove Drive slowed to a crawl Saturday morning as hundreds, if not thousands of vehicles made their way up to the space center. Many opted to find parking in nearby neighborhoods, virtually filling up residential streets.
Those who did make it in to the event experienced congested sidewalks and long lines for the various stations, films and presentations, as well as fall heat that reached the mid-90s.
The weather and crowded conditions didn't seem to matter to most, as attendees crowded around tents to hear about missions and technology from dozens of JPL scientists and engineers.
Many gravitated to the large "Mars Exploration" tent in JPL's outdoor courtyard, where a full-scale model of the Curiosity rover currently cruising the surface of Mars some 140 million miles away was on display.
The tent also featured rovers being driven by remote control to demonstrate how they move, including "Scarecrow," which is used to test how Mars' terrain affects rover wheels.
This was the first open house for engineer CJ Giovingo, who stood in one corner of the tent fielding questions from guests.
Giovingo said she heard all kinds of questions, ranging from high school kids asking how to get a job at JPL to attendees weighing the merits of teaching the metric system.
"You do your job on a day-to-day basis and…you kind of forget about all the people who are behind you," she said. "So it's exciting to let the public in and get to share our enthusiasm and our passion and hear what people are really excited about."
Giovingo was all smiles explaining the project she's currently working on, NASA's upcoming Mars 2020 Mission.
The mission is designed specifically to seek past life on the Red Planet, with plans to drill for samples, then store them with the hope that a future mission would bring those samples back to Earth.
Systems engineer Elyse Fosse said one particular line of questioning was expected leading up to the event.
"We're getting a lot of 'The Martian' questions," Fosse said, referring to the newly released sci-fi film starring Matt Damon as an astronaut stranded on the Red Planet. "A lot of people are asking how technically accurate the movie was."
Also featured was a longtime favorite where guests lay on the ground and a mini rover rolls across their backs.
"It felt weird," said 10-year-old Garret Roth, who came to Open House with his parents and cousin from Shadow Hills.
Garret said he is interested in one day working for NASA and that his favorite part of the open house was seeing and learning about the planets in the solar system and beyond.
Many of the stations were geared toward the younger attendees, with engineers offering hands-on learning about radio waves, electricity and even a 3D view of the Martian surface.
"I want to know about the water on Mars," said Sai Skrishnan, 12, who visited with her family from Cypress Hill. "Like, would there ever be life on Mars?"
John Bryan made the trip from Redondo Beach with his 12-year-old son Henry, friend Rob Holvey and his son Alec, also 12, and said the event was crowded, but "very cool."
"JPL is really kind of a geek haven," said Bryan, who braved traffic and long lines for his first visit to the space center. "It's really surprising to me how many people are here."
Like many kids, Bryan said he grew up wanting to be an astronaut. He said he and Holvey brought their sons to the open house to instill a joy for science.
"But in reality it's just so we can geek out," he added.
JPL spokeswoman Veronica McGregor estimated they saw roughly the same attendance as last year's open house, but said the main reason Saturday's event was closed off so early was due to the amount of people who arrived first thing in the morning.
An estimated 21,000 people were at JPL by noon Saturday, McGregor said, compared to the steady stream of people the event typically sees.
About 24,000 people were able to get in on Sunday, due in part to close crowd monitoring and social media notifications to those waiting it out for a chance to make it in. Day 2 of the open house officially closed down entry at 2:30 p.m.
"I wouldn't be surprised if we tried a few different things next year," she said.
The feedback JPL is receiving through social media has been very rewarding, McGregor said, with some online comments going as far as to mention scientists and engineers by name and thank them for inspiring guests.