Nasa says contact has been re-established with the moon-bound Capstone satellite.
The announcement came at 3.30am this morning NZT - ending a day and a half of the Rocket Lab-launched craft being lost in space.
The astronomy community first noted an apparent loss of signal at 1.54pm on Tuesday NZT. Nasa confirmed problems several hours later.
At midday on Wednesday, the US space agency updated that a scheduled course-correcting manoeuvre had been delayed as attempts to reach Capstone continued.
This morning's good-news update was a one-liner, with Nasa promising details to follow.
Capstone was launched on a Rocket Lab Electron on June 28.
Rocket Lab's "Lunar Photon" - the Electron's upper stage - then lifted Capstone into a high Earth orbit before setting it on a course for the moon - at which point it handed the reins to US private operators Advanced Space and Terran Orbital who are managing Capstone's flight to the moon.
Rocket Lab spokeswoman Morgan Bailey said although her company had handed over control to Advanced Space after successfully completing its two legs of the mission, it would assist if it could.
"Right now Lunar Photon is on the same trajectory as Capstone, is performing well, and has propellant remaining, so we're working with Nasa to assess what support Lunar Photon might be able to provide to the mission," Bailey said.
The first sign something was wrong was when US astronomer Jonathan McDowell, who works for Nasa's Chandra X-ray observatory, tweeted: "Various sources are expressing concern for the status of the Capstone spacecraft."
McDowell retweeted screen grabs of failed attempts to reach Capstone by the Deep Space Network, a series of radio dishes in Madrid, Canberra and Goldstone in California.
A New Zealand space industry insider told the Herald: "This suggests that the Capstone spacecraft stopped talking to the ground shortly after separating from the Rocket Lab 'bus'. Rocket Lab would have done its job but the mission managers for the spacecraft itself will be sh*****g bricks right now."
Nasa confirmed problems overnight, posting: "Following successful deployment and start of spacecraft commissioning on July 4, the Capstone spacecraft experienced communications issues while in contact with the Deep Space Network. The spacecraft team currently is working to understand the cause and re-establish contact. The team has good trajectory data for the spacecraft based on the first full and second partial ground station pass with the Deep Space Network. If needed, the mission has enough fuel to delay the initial post-separation trajectory correction manoeuvre for several days. Additional updates will be provided as soon as possible."
Following Capstone's launch into low Earth orbit, Rocket Lab used the Lunar Photon - or "satellite bus" - to lift the craft into progressively higher orbits over six sets of manoeuvres.
The final burn on July 4 - symbolically, Independence Day in the US - saw the microwave oven-size Capstone separate from Rocket Lab's Photon and deployed on its ballistic lunar transfer trajectory to the moon. The 1.3 million km journey will take until November 13.
Rocket Lab and Nasa described the final burn as a success.
"The spacecraft is now being flown by the teams at Advanced Space and Terran Orbital," Nasa said on July 4.
Terran Orbital designed and built Capstone, while Advanced Space runs mission operations. Both are US companies.
The plan is for Capstone to arrive at the moon on November 13, when it will be placed in an experimental halo orbit, which Nasa wants to use for Gateway - a planned small satellite station that will form part of its Artemis programme to return astronauts to the moon.
Nasa budgeted US$30m for Capstone, of which US9.95m ($14m) went to Rocket Lab.
The space agency will would have been nervous during the craft's day-and-a-half of being AWOL.
On June 13, Rocket Lab rival Astra lost two Nasa weather tracking satellites after a failed launch.