At Seattle-based Spaceflight Industries, the size of the spacecraft continues to grow. The new SSO-A, assembled in a tall warehouse in Auburn, stands nearly 20 feet tall.

This week, the stages of the spacecraft are bolted together and scheduled for vibration tests designed to find out if the SSO, which stands for Sun Synchronous Orbit, is ready for the violence of launch.

If those tests go as expected, the company prepares to bolt it onto a SpaceX Falcon 9 rocket for launch in 2018.

Aboard the SSO, there are attachments points and dispensers for 120 satellites. Some of those satellites are the size of an office desk; others barely larger than a hockey puck. So who’s buying?

“You have well-established aerospace companies, you have new companies that have never put anything into space,” said Jeff Roberts, Spaceflights head of launch programs.

Roberts came to Spaceflight just 18 months ago, part of the company’s rapid growth, which has gone from 100 to 150 employees in just the past year.

The commercialization of space is reducing the cost of getting there. Consider the old model for launching a satellite, usually large or very large, which involves the dedication of an entire rocket, usually from NASA itself or maybe the Russians.

Spaceflight doesn’t talk about what it costs in specific numbers, but the satellites that will hitch a ride aboard the SSO-A come from nearly 50 private and government entities from 16 different countries.

“You have universities, you have foreign companies, you have U.S. companies,” said Roberts.

One way to think of what Spaceflight is offering is this. If you want to be the sole passenger aboard a private jet flying across the ocean, that’s going to be very expensive. If you took 20 of your friends and divided the cost, far less expensive. If you bought a seat aboard a scheduled commercial airline, even cheaper.

Spaceflight is a consolidator, so you could think of this trip aboard SSO-A as a charter airliner, with SpaceX providing the engines.

What does SSO really mean anyway? The idea says Spaceflight is to have all of these satellites facing the sun, in an orbit running from the north to the south pole. Hence, Sun Synchronous Orbit.