Planet Labs flock release
Planet began sending its first "flock" of Doves from the International Space Station in 2014. Now, the company operates the world's largest constellation of Earth observation satellites. Credit: Planet

SAN FRANCISCO — The international space station is beginning to jettison miniature satellites at a steady pace as astronauts work through a batch of 33 cubesats slated to fly through a window in the Kibo module.

On Feb. 11, Japanese astronaut Koichi Wakata launched the first four of 33 cubesats sent to the international space station in January aboard Orbital Sciences Corp.’s Cygnus cargo mission. The cubesats deployed Feb. 11 were Earth imaging spacecraft built by San Francisco-based Planet Labs, which is planning to launch its entire 28-satellite Flock-1 constellation from the orbiting outpost. 

In addition, space station astronauts are preparing to launch in the coming weeks two cubesats built in Lithuania, one from Peru, a NanoSatisfi Inc. ArduSat and a Southern Stars Group LLC SkyCube, said Mike Johnson, chief technology officer for NanoRacks LLC, the Houston-based space services provider that made arrangements for the tiny satellites to travel to the space station and helped pave the way for their recent launch through the Japanese module.

NanoRacks also built the mechanism being used to eject the tiny satellites. Each NanoRacks Cubesat Deployment System holds six spacecraft and the mechanisms are stackable to enable eight of them, for a total of 48 cubesats, to fit on a single pallet aboard Kibo. With the help of the Japanese slide table and robotic arm, astronauts began launching two cubesats at a time, then waiting a couple of orbits to prevent collisions. 

Since NASA published images in October 2012 of the first five cubesats launched from the international space station, cubesats developers in industry and academia have contacted NanoRacks to express keen interest in traveling the same path into orbit. The company has more than 50 cubesats under contract to fly from the space station and memoranda of understanding for more than 100 more satellites. 

“We’re booked for cubesat launches for the next couple of years,” said NanoRacks Managing Director Jeffrey Manber.

While some scientists say they do not want to launch from the space station because its low altitude would limit the life of their satellites, many other cubesat builders are eager to reach orbit as quickly as possible. 

“Without an onboard propulsion system, the [satellites’ lives] will be fairly limited,” said Chris Boshuizen, Planet Labs chief technology officer. “Our [business] model is based on our ability to mass-produce satellites. Instead of building a more sophisticated satellite with a 10-year lifetime, we chose to build a much simpler spacecraft with a design life of a couple of years and replenish the constellation.”  

Cubesat missions seeking rides into space as a secondary payload often wait years. In contrast, NanoRacks can send small satellites to the space station on U.S., Russian or Japanese launch vehicles in nine months on average, Manber said. 

Jason Dunne, co-founder of Made in Space, the company preparing to send a 3-D printer to the international space station later this year, said the orbiting outpost may become Grand Central Station for cubesat launches. Made in Space is working with NASA to determine whether cubesats also could be built on the orbiting outpost using additive manufacturing.