WASHINGTON — NASA documents about the selection of commercial cargo contracts announced in January show that SpaceX had the highest technical ratings of the three winning companies, but also, by one metric, the highest price.

NASA released Feb. 5 the source selection statement for the Commercial Resupply Services (CRS) 2 contracts, which the agency awarded Jan. 14 to Orbital ATK, Sierra Nevada Corporation (SNC) and SpaceX to transport cargo to and from the International Space Station. The statement provides details about NASA’s evaluation of the CRS-2 proposals and the rationale for selecting the winning companies.

NASA evaluated the CRS-2 proposals on three major factors: price, past performance and “mission suitability,” which examines the bidder’s technical and management approach as well as use of small businesses. NASA weighted price approximately the same as the combination of mission suitability and past performance, with mission suitability alone more important than past performance.

SpaceX did the best of the three companies in mission suitability, with 922 out of a 1,000 possible points. Orbital ATK had a score of 880 and SNC 879. All three companies received a “high” confidence rating in past performance.

The document did not provide specific price information, only that reviewers deemed the prices “reasonable” based on “other competitive and historical prices.” The document states, though, that SpaceX’s prices were “notably higher” that Orbital ATK, which had the lowest prices, and “somewhat higher” than SNC.

The price used in the evaluation, though, was based only on one aspect of the overall cargo delivery service requested in the CRS-2 competition. According to the statement, evaluators calculated integration prices for cargo services, plus the cost of transporting pressurized cargo to the station assuming each company delivered half of NASA’s estimated demand each year.

However, the price calculation did not include cost for unpressurized cargo delivery to the station. It did not also include pricing for taking cargo away from the station either for destructive reentry in the Earth’s atmosphere or return to the Earth.

The use of pressurized cargo to the station for price calculations, those familiar with the evaluation process say, was used because it was common among all proposals. Orbital ATK does not return cargo to Earth with its Cygnus spacecraft and requires a separate mission to deliver unpressurized cargo to the station. SpaceX, by comparison, does not dispose cargo through destructive reentry. Taking those additional services into account could result in a more favorable overall price per kilogram of cargo for SpaceX.

William Gerstenmaier, NASA associate administrator for human exploration and operations and the agency official who made the final decision on the CRS-2 awards, said the higher SpaceX costs for pressurized cargo delivery had to do with the production and size of the company’s Dragon spacecraft, which will also have a version carrying crew.

“Having two separate vehicles with separate production lines contributed to the prices, as well as the vehicle sizes which impact the cargo capacity and number of missions needed per year to deliver the required amount of upmass,” he wrote. The statement doesn’t list cargo capacities of the vehicles, but notes Orbital’s Cygnus vehicle can carry more mass than Dragon, and Sierra Nevada’s Dream Chaser even more.

The differences in technical scoring or pricing did not play a major factor in NASA’s final decision to award all three companies with CRS-2 contracts. “All three proposals meet or exceed the requirements of the RFP and will provide good value to NASA and the ISS,” Gerstenmaier concluded.

The source selection statement also confirmed that, beyond the three winning companies, Boeing and Lockheed Martin were the only others to submit proposals. The document, however, offers few details about why those companies failed to win contracts.

According to the statement, an initial review of the proposals submitted in December 2014 found that Lockheed Martin was not in the “competitive range” and thus was no longer considered for evaluation. NASA contacted the other four companies in May 2015, who updated their proposals by July.

In November, NASA decided to narrow the competitive range of CRS-2 proposals again, excluding those proposals “that were no longer among the most highly rated.” That dropped Boeing from the competition, although the source selection statement gave no additional information on what set Boeing apart from the other three companies.

NASA asked the remaining companies to revise their proposals to take into account schedule changes in the CRS-2 program, with the first missions, originally scheduled for 2018, now planned for late 2019. The updates, delivered to NASA by a Dec. 8 deadline, resulted in unspecified updates to pricing, but no changes to the mission suitability and past performance scoring.