NASA has released 21 different models on its website for visitors to 3D print.

The move is the latest made by the space agency to get more involved in 3D printing, having announced its partnership with MakerBot to launch a "Mars Base Challenge" several months ago and creating the first full 3D model of Eta Carinae Nebula a few weeks ago, according to 3DPrint.

The 21 printable objects include Mars' Gale Crater and several probes, such as the Mars Odyssey, the Kepler, the Voyager and the Rosetta. Two asteroids - Eros and Itokawa  - are also available, as are models of the surfaces of the Moon and Mars, CNET reported.

NASA cut some of the round objects in half to make it easier for people to print the models, which are available in STL format. The agency said that the files are made for 3D printing, but some of the models need to be changed before being sent to the printer. It might also be almost impossible to 3D print some of the models because they include parts that are very small, making an extremely accurate, high quality printer necessary at times, 3DPrint reported.

"This .stl file was produced by scaling the original model and converting it directly to .stl format," NASA explained. "It may not yet be ideal for printing."

The models can be downloaded for free, and have been scaled down to 4 inches in the longest dimension, CNET reported. Images and textures are included on the agency's site for creative 3D artists to use as resources for their work. The site also features interactive pages and games that provide the chance for artists to learn more about operations at NASA.

Those interested in creating art with 3D printing can go to the NASA 3D Resources beta page to play around with the space models.