WASHINGTON — NASA awarded contracts valued at several billion dollars Jan. 14 to three companies, including one newcomer, for commercial cargo deliveries to the International Space Station through 2024.

The agency announced it awarded Commercial Resupply Services 2 (CRS-2) contracts to Orbital ATK, Sierra Nevada Corporation and SpaceX for cargo missions to and from the ISS starting in late 2019. The contracts, which run through 2024, include at least six missions for each company.

Orbital and SpaceX offered versions of their Cygnus and Dragon vehicles, respectively, that currently support the station. NASA said that Orbital offered three versions of Cygnus, two to transport pressurized cargo to the station and one for unpressurized cargo. Those missions would launch on either Orbital’s own Antares rocket from Wallops Island, Virginia, or a United Launch Alliance Atlas 5 from Cape Canaveral, Florida.

SpaceX offered two versions of its Dragon spacecraft, one that would berth with the ISS with the assistance of the station’s robotic arm as Dragon missions currently do, and one that would dock with the station without the arm’s assistance, as future crewed Dragon missions will do. the Dragon spacecraft will be able to land on land as well as splashdown at sea as it does currently.

Sierra Nevada, the newcomer to the CRS program, will provide two versions of its Dream Chaser lifting body vehicle: one that berths and one that docks. Dream Chaser will be able to glide back to a runway landing to any number of potential sites, although Kirk Shireman, NASA ISS program manager, said the Kennedy Space Center is the most likely site in order to get experiments returned from the station into the hands of scientists as quickly as possible.

Shireman said the berthing and docking options exist for both Sierra Nevada and SpaceX because while berthing requires the assistance of ISS crewmembers operating the station’s arm, those spacecraft can use different ports on the station with larger hatches.

NASA officials, in a briefing at the Johnson Space Center, declined to assign a monetary value to any of the awards. Shireman said that since each company offered several mission types with varying capabilities and prices that NASA can choose from as needed, the agency could not estimate the value of the contracts.

Shireman did say the total value of the contracts will be “nowhere near” the maximum value in the request for proposals of $14 billion. Orbital, in a Jan. 14 press release, estimated the value of its contract at between $1.2 billion and $1.5 billion.

“There is a general sense that it’s a reasonably big number, over a billion dollars,” Mark Sirangelo, corporate vice president for Sierra Nevada Space Systems, said of his company’s award in a Jan. 14 interview, but added that uncertainties in when NASA will order missions, and what kinds, kept him from offering a more specific estimate.

The award is something of a lifeline for Sierra Nevada, which had been looking for alternative business for Dream Chaser since losing the commercial crew competition to Boeing and SpaceX in 2014. The cargo version of Dream Chaser, which the company unveiled last March, is based on the crew version but features an external cargo module and foldable wings, allowing it to fit inside the payload fairing of an Atlas 5 or an Ariane 5.

“There is the excitement of a big win,” Sirangelo said. “We certainly had a lot of ups and downs and a lot of times where we didn’t know if we were going to have the next step. I think coming back from the dead a few times, like a phoenix, is a really fun thing.”

At least five companies submitted CRS-2 proposals to NASA in December 2014. In addition to the three winners, Boeing and Lockheed Martin also offered to transport cargo to and from the ISS. NASA officials said they could not discuss the reasons why those companies lost until after it completed briefings with those companies and released the source selection statement.

Boeing proposed a version of its CST-100 Starliner vehicle it is developing for NASA’s commercial crew program. NASA notified Boeing in November the company was no longer being considered for a CRS-2 award, but did not give a reason at the time.

Lockheed Martin proposed a system where a robotic space tug called Jupiter would transport cargo modules dubbed Exoliners, placed into orbit on Atlas 5 launch vehicles, to and from the station. The company said Jupiter could also be used for other applications, such as satellite servicing.

NASA delayed the contract award, originally scheduled for June 2015, several times, saying it needed more time to evaluate the proposals. “It just turned out to be a really complicated process,” Shireman said of the evaluation of the various mission types offered by companies. “The real reason for the delay was us being very deliberate and very careful, making sure we made the right decision.”

Orbital and SpaceX won the original CRS contracts in December 2008. Orbital received a $1.9 billion contract for eight Cygnus missions and SpaceX received a $1.6 billion contract for 12 Dragon missions. NASA has since added two Cygnus and three Dragon flights to those contracts, for an unspecified additional amount.

Shireman said those CRS contracts would be further extended to provide additional cargo flights until the CRS-2 missions begin in late 2019. He said NASA signed a task order with SpaceX in December for a flight “to bridge the gap” before the CRS-2 missions begin. NASA also has a similar proposal from Orbital for additional flights currently under evaluation.