NASA has ordered five more missions from SpaceX to resupply the International Space Station, in a new deal that was signed in late December, Space News reports. That means the company will make a total of 20 cargo trips to the ISS for NASA under its original resupply contract — eight more trips than originally planned. The new missions are valued somewhere around $700 million in total, according to Space News.

The company will make a total of 20 cargo trips to the ISS through 2018

NASA's other commercial space station supplier, Orbital ATK, did not receive any additional trips; the company will resupply the ISS a total of 10 times for NASA under its original contract. It's not clear exactly why SpaceX has received so many more orders than Orbital. SpaceXalso holds another contract with the agency to transport astronauts to and from the space station starting in 2017.

Under the current cargo contracts, SpaceX and Orbital are supposed to build and operate spacecraft that can bring supplies to the ISS. The contracts were first awarded in 2008, and they originally tasked each company with delivering cargo through 2016. The terms of the contracts have expanded since then: SpaceX and Orbital are expected to resupply the station through 2018. And a NASA spokesperson told Space News that the agency can order an indefinite amount of launches and cargo through the contract, but each company is promised a maximum of $3.1 billion each for the launches.

Both companies will continue to resupply the space station once their original contracts expire. SpaceX and Orbital were awarded NASA's second round of resupply contracts in January, along with another spaceflight company Sierra Nevada. These second contracts cover launches to the ISS from 2019 through 2024, though the financial details weren’t disclosed. NASA said it would order at least six missions from each company, and the total cost would vary depending on how many flights are performed.