NASA and SpaceX, the agency’s front-running Commercial Orbital Transportation Services (COTS) partner, declared themselves ready for a late April launching of the first privately developed cargo mission to the International Space Station, following an April 16 Flight Readiness Review (FRR).

The three-week flight test, a bid to regain some of the six-year-old NASA initiative’s lost ground by combining the objectives of what were previously considered separate Demo 2 and 3 missions, is scheduled for launch from Cape Canaveral on April 30 at 12:22 p.m. EDT, NASA and SpaceX announced as the Johnson Space Center hosted FRR drew to a close.

“I think the teams are very well prepared,” Associate Administrator for Human Exploration and Operations Bill Gerstenmaier said during a briefing after the 4.5-hr. FRR. “It was a thorough discussion. SpaceX has done a lot of work to this point. I was impressed with the overall work . . . I think there is a good change we will make April 30th.”

He cautioned, however that “there is still quite a bit of work to be done to validate software testing.” SpaceX will carry out that work at company facilities in Hawthorne, Calif., as well as at Cape Canaveral, Fla., with the flight hardware. Those test results will be presented to NASA for review on April 23.

“I think we’ve got a pretty good shot, but i think its worth emphasizing that a lot can go wrong with a mission like this,” SpaceX CEO Elon Musk said.

If each in a carefully scripted series of milestones in the early phase of the flight is met, the unpiloted SpaceX Dragon supply capsule should move within close proximity of the space station early on May 3.

Astronauts Don Pettit from NASA and Andre Kuipers from the European Space Agency will be positioned at a control console for Canadarm2, the station’s 58-ft.-long robot arm, inside the station’s Cupola observation deck, ready to grapple and berth the free-floating, 16-ft.-long freighter. After Pettit’s grapple, which could come at 8:30 a.m. EDT, Kuipers will take control of the arm, maneuvering Dragon to the Earth-facing berthing port on the station’s U.S. segment Harmony module by noon EDT.

Mission officials are prepared to respond to slips. Dragon has a 24-hr. loiter-in-orbit capability.

Dragon will remain berthed for 18 days, allowing the station’s three tenants to offload about 1,150 lb. of low-priority cargo—food, clothing, crew personal items, spare parts—as well as a NanoRacks-CubeLabs Module with proprietary research. The station crew will also re-stow the capsule with about 1,450 lb. of equipment for return to Earth.

In all, the combined test mission includes 16 objectives, the most critical focused on Dragon’s pre-grapple navigation and communications with the station, including demonstrations of the astronauts’ ability to stop the spacecraft and abort the rendezvous.

Orbital Sciences Corp., the other COTS partner, is shooting for its own cargo demonstration mission as early as this summer.