Updated 12:20 p.m. Eastern

WASHINGTON — Rocket Lab, a U.S.-New Zealand company developing the Electron small launch vehicle, declared success on its first launch May 25, although the rocket failed to reach orbit.

In a statement, the company said the Electron lifted off from its private launch complex on New Zealand’s Mahia Peninsula at 12:20 a.m. Eastern (4:20 p.m. local time.) The rocket reached space on an apparent suborbital trajectory three minutes later.

“It was a great flight. We had a great first stage burn, stage separation, second stage ignition and fairing separation,” Rocket Lab Chief Executive Peter Beck said in a statement. “We didn’t quite reach orbit and we’ll be investigating why, however reaching space in our first test puts us in an incredibly strong position to accelerate the commercial phase of our program, deliver our customers to orbit and make space open for business.”

“We’re looking at all our data and trying to find the root cause” for failing to make it to orbit, Beck said in a phone interview a few hours after the launch. “Until we look at the data it’s really hard to say.”

Beck, in a media teleconference later May 25, offered few additional technical details about the launch, but said that the company was pleased with the mission overall. “We’re very, very happy with the vehicle’s performance,” he said. “On this first flight we’re well ahead of where we needed to be.”

Electron is a two-stage vehicle designed to place payloads weighing up to 150 kilograms into sun-synchronous orbit. The first stage is powered by nine Rutherford engines, using liquid oxygen and kerosene propellants, while the second stage uses a single modified Rutherford engine.

As designed, the Electron’s first stage fires for two and a half minutes before separating. The second stage then ignites for a burn lasting nearly five minutes, with payload fairing separation taking place a little more than three minutes after liftoff. The company didn’t disclose in its statement if the timing of those events for this launch matched that plan.

The launch carried only a test payload, including instrumentation to collect data on the launch environment. “It’ll probably take us a couple of months to work through the data,” he said in the interview, before performing another launch. That second Electron vehicle, he said, is already built and sitting in the company’s factory.

“There were a lot of firsts today: building the range and having all that infrastructure work, a great first stage burn,” he said. “We validated and ticked off an awful lot today.”

Rocket Lab is planning three test launches of the Electron before beginning commercial flights. Beck said in a May 23 interview that the company was considering flying some commercial payloads on those later test flights, depending on the performance of the vehicle and instrumentation needs.

Rocket Lab’s customers include a mix of government agencies and companies. NASA awarded the company a launch contract under its Venture Class Launch Services program in October 2015. Moon Express has a contract for multiple launches, with the goal of performing the first launch before the end of this year in order to meet the requirements of the $20 million Google Lunar X Prize. Planet and Spire, two companies operating constellations of cubesats, also have booked launches with the company.

This was the first orbital-class launch to take place from New Zealand. The launch was licensed by the U.S. Federal Aviation Administration because the company is headquartered in the United States, although most of its operations are in New Zealand.

The launch site, and coordination with local officials to clear airspace and seas for the launch, worked as planned, but Beck said in the media teleconference it took a “huge effort” to get everything in place. “If anybody has ever contemplated building a launch range, I’d advise against it, because it’s certainly a lot more involved than even we, four years ago, thought it would be,” he said.

“We have learned so much through this test launch and will learn even more in the weeks to come,” Beck said in the statement. “It has been an incredible day and I’m immensely proud of our talented team.”