WASHINGTON, July 18 -- Space-based 3D printing of hardware such as a fully functional small spacecraft is still far from being a reality at least in the short term, according to a new U.S. report out Friday that believed "a substantial degree of exaggeration, even hype" exists about this technology that has attracted significant attention recently.

Although 3D printing, also known as additive manufacturing, is advancing rapidly and is increasingly used on the ground for an expanding number of industrial purposes, the basic technology is " still relatively young" and its application in space "is not feasible today, except for very limited and experimental purposes, " said the report from U.S. National Research Council, which was written at the request of the U.S. space agency NASA and the U.S. Air Force.

The specific benefits and potential scope of the technology's use in space remain undetermined, the report acknowledged, adding that the realities of what can be done today on the ground demonstrate the "substantial gaps" between the vision for 3D printing in space and its limitations.

"Many of the claims made in the popular press about this technology have been exaggerated," Robert Latiff, chair of the committee that wrote the report and a former Air Force Major General, said in a statement.

"For in-space use, the technology may provide new capabilities, but it will serve as one more tool in the toolbox, not a magic solution to tough space operations and manufacturing problems."

According to the report, multiple limitations prevent in-orbit 3D printing, a process of joining materials, usually layer on layer, to make objects from 3D model data, from coming true in the near future.

The vacuum of space, zero gravity, and intense thermal fluctuations all pose extreme and harsh environmental obstacles as these factors are important not only in terms of completing the manufacturing process but also in how they can alter the integrity of the final product, the report said

Furthermore, a number of impacts and obstacles need to be considered in the cost-benefit equation for space-based manufacture, said the report.

The largest disadvantages stem from the high costs of equipment operation, maintenance, and infrastructure platforms such as a reliable power source that does not detract from spacecraft operations, it said.

Automation presents another unknown cost. The report said that 3D printing currently requires extensive human presence and participation on the ground, sometimes just to move parts from one machine to the next, but human labor in space is very expensive.

"Because the most obvious applications are for human spaceflight and exploration and for military missions, the government cannot expect industry to invest in technology developments that do not have a clear path to profit," it said.

The report recommended that NASA and the U.S. Air Force create a roadmap for developing space-based 3D printing technology as well as identify experiments that they can develop and test aboard the International Space Station during its remaining 10 years of service.

Specially, it disputed the claim by the U.S. Air Force that 3D printing could help meet its "most pressing requirement" to reduce the cost of launching payloads to orbit.

"At the present time, it is too early to be certain that space- based additive manufacturing will make it possible to reduce the cost of space launch," the report said.

"It is also too early to determine how the Air Force may best make use of this technology, although its potential for the deployment of structures too large or fragile to fit in current launch vehicle payload shrouds could prove attractive for some national security missions."