WASHINGTON — Spaceflight, a company that arranges launches for small satellites, announced May 17 is it purchasing a launch from Rocket Lab for payloads seeking access to a less common orbit.

Seattle-based Spaceflight didn’t disclose the terms of the deal for the Electron launch, although Rocket Lab has previously quoted a launch price of as low as $4.9 million for a dedicated launch. The companies have also yet to determine the launch date for the mission.

Spaceflight said it purchased the Electron to serve payloads going to orbits not frequently served today. The company brokers launches of smallsats as secondary payloads on other launches, and in 2015 purchased a dedicated SpaceX Falcon 9 mission. Most of those launches, including its upcoming Falcon 9 mission, go to sun-synchronous orbit.

The company said it will use this Electron for payloads seeking to go to lower inclinations. “There are numerous rideshare launches each year to sun-synchronous orbit, but getting to 45 to 60 degrees is hard to find, and can cost the equivalent of buying an entire rocket,” Curt Blake, president of Spaceflight’s launch business, said in a statement about the deal.

Such missions, he said, include remote sensing spacecraft that want more frequent access to mid-latitude regions, versus a sun-synchronous orbit that offers a single pass per day over a given area. “We are thrilled to be working with Rocket Lab to enable our customers’ remote sensing missions that require high revisit time over North America, Europe and the Middle East,” Blake said.

The announcement comes as Rocket Lab continues to prepare for its first launch, planned during a 10-day window that opens at 5 p.m. Eastern May 21 from its New Zealand launch site. The company announced May 16 that it had completed a “wet dress rehearsal” for the launch, a practice countdown that includes fueling of the vehicle, in advance of the flight.

The company, which is headquartered in the United States although the bulk of its operations are in New Zealand, has also received a launch license from the U.S. Federal Aviation Administration. The license, dated May 15, covers the company’s three planned test launches of the Electron from its New Zealand site, each carrying an “inert payload” to low Earth orbit.