WASHINGTON — NASA has issued a request for proposals to purchase as many as five cubesat buses that the agency says will be used to demonstrate new technologies while also stimulating the emerging smallsat industry.

The request for proposals for NASA’s Pathfinder Technology Demonstrator project, issued Feb. 12, calls for buying one six-unit cubesat bus, with options for four more, that NASA will use for flight tests of advanced smallsat technologies under development at the agency.

“The team is excited to solicit proposals for a basic small satellite bus design that will be adaptable for use on a series of low-cost missions for NASA, and possibly for other customers,” said John Marmie, Pathfinder Technology Demonstrator project manager at NASA’s Ames Research Center, in a Feb. 12 statement.

The request for proposals calls for a “state of the art satellite that would require little, or preferably no new technology development for the bus sub-systems,” allowing NASA to add technology demonstration payloads to it. The first cubesat would fly a low-thrust propulsion system, with future missions incorporating propulsion, communications or attitude control technologies.

A six-unit cubesat uses the standard cubesat form factor — 10 centimeters on a side — as a building block for a larger spacecraft, in this case 10 by 20 by 30 centimeters in size. The spacecraft has a mass of no more than 12 kilograms and should be able to generate at least 45 watts of power, according to NASA’s requirements. One-third of the spacecraft’s volume must be available for NASA’s technology payloads.

NASA has developed a number of cubesats in the last several years for science and technology demonstration missions. Typically, though, NASA developed both the satellites and their payloads in-house, rather that purchase satellite buses from commercial vendors.

NASA says its decision to purchase smallsat buses is intended to stimulate demand for such spacecraft commercially. “We are seeking a spacecraft bus that will meet our needs while avoiding over-specification so that the vendor can propose a spacecraft that might also meet the needs of a broader market,” said Andrew Petro, program executive for NASA’s Small Spacecraft Technology Program.

The six-unit cubesat is a relatively new form factor in the field, which has in recent years standardized on smaller designs, such as the three-unit cubesat. Planet Labs has launched more than 100 three-unit cubesats for its remote sensing constellation, while Spire also plans to launch more than 100 three-unit cubesats to collect weather and maritime monitoring data.

Proposals for providing the Pathfinder Technology Demonstrator cubesat buses are due to NASA March 30. The agency expects to award a fixed-price contract in June, with the first cubesat bus to be delivered at the end of 2017.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...