NEW YORK — NASA’s new spaceship intended to send astronauts into space and ultimately the moon has passed an early design review amid uncertainty over whether the rocket slated to launch it into orbit will ever fly.

The spacecraft, a capsule-based vehicle called Orion, passed a preliminary review this month to make sure there are no glaring problems with the design, which NASA plans to replace its aging space shuttle fleet. Orion capsules are slated to begin operational flights in 2015 and, under the current plan, return astronauts to the moon by 2020.

“I’m very excited about the design of this spacecraft,” said Jeff Hanley, manager of NASA’s Constellation program developing Orion and its Ares 1 rocket booster. “It’s a very capable spacecraft not just for low Earth orbit, but also for returning astronauts to the vicinity of the moon.”

The Orion spacecraft is a 5-meter-wide capsule designed to carry at least four astronauts on crew change flights to the international space station or on longer expeditions to the Moon. NASA originally envisioned launching six people aboard Orion, but scaled down the crew size for the first flights earlier this year in order to maintain the 2015 flight schedule.

Orion’s preliminary design review, a major project milestone, comes as uncertainly looms over the spacecraft’s Ares 1 rocket, a two-stage booster was slated to make its first test flight on Oct. 31.

Rocket limbo

Earlier this month, an independent committee appointed by the White House to review NASA’s plans for human space exploration came up with four general options for consideration by President Barack Obama. Only one of those options, a baseline study, included the Ares I rocket while others replaced it with existing rockets or NASA’s larger, heavy-lift Ares 5 booster planned to support eventual moon missions.

The committee, led by former Lockheed Martin chief Norman Augustine, is expected to file a final report to the White House in upcoming weeks. Any presidential decision to eliminate the Ares 1 rocket would add years to Orion’s development, project managers said, but NASA has a wealth of experts that could be ready to review that option.

“It’s important for folks to understand that the rocket and the spacecraft fly as an integrated system,” Hanley said in a Tuesday teleconference. “So whatever we do with respect to the launcher, we would have to go back and redo, to some extent, work that is already done.”

That could mean a considerable reevaluation of Orion’s design, adding up to two years to NASA’s already extended development schedule. An independent report released this month found that NASA would have to spend billions more than planned if it abandoned the Ares 1 rocket and replaced it with an human-rated Delta 4 Heavy rocket currently available for unmanned satellite launches.

“I think we’re very much staying on the plan right now until we receive new direction,” Hanley said.

To date, NASA has spent $3.1 billion developing the Orion spacecraft and $7.7 billion on the Constellation program as a whole. The agency plans to spend about $35 billion on the program through 2015. The Augustine committee has said NASA does not have the budget to meet its ultimate target — returning astronauts to the moon by 2020 — unless it receives a substantial boost from the Obama Administration.

Orion work ahead

Currently, the Orion crew capsule is about 136 kilograms heavier than its target weight of about 9,706 kilograms, spacecraft project manager Mark Geyer told reporters. NASA has about 453 kilograms of margin and expects to hit its weight target soon, he added.

Geyer added that engineers still have to complete a design review of a critical cover for Orion’s landing parachutes to make sure it is safe and efficient. That is expected to be completed soon.

The final critical design review for Orion, the Ares 1 rocket and other systems are not scheduled until about 2011 or later, when NASA would begin building flight hardware, Hanley added.

Once the Augustine committee submits its report, the options it compiled will be evaluated by the Obama Administration and NASA’s new chief Charles Bolden, a former shuttle commander.

“We have a few weeks left to wait and see what happens with this review and what direction Charlie Bolden and the team wants to take us,” Hanley said. “So we wait with great anticipation.”