On Thursday in Kazakhstan, at 4:40am EDT, a Soyuz rocket took off carrying NASA astronaut Nick Hague and Russian cosmonaut Aleksey Ovchinin toward the International Space Station. The ascent proceeded normally until the separation of one of the rocket's booster stages, by which point the crew had already experienced microgravity.

Because the Soyuz spacecraft did not reach orbit at the point of this booster failure, the crew was forced to make a rapid ballistic descent likely under high g-forces. After about 20 minutes of uncertainty, Russian officials confirmed the crew were ok and had landed about 20km east of Dzhezkazgan, a city in central Kazakhstan. As rescue crews arrived, Hague and Ovchinin were reported in "good condition" and found out of the capsule.

Little additional information has been provided. Roscosmos, the Russian firm that operates the nation's space agency and is responsible for Soyuz launches, will not hold any news conferences today. The head of Roscosmos, Dmitry Rogozin, said a state commission has already been established to study the accident.

This failure raises serious questions about the future of the International Space Station, as, since the space shuttle's retirement in 2011, the Soyuz spacecraft and rocket were the only means by which crews have been able to reach it. With Thursday's failed launch, just three people remain on the station: American astronaut Serena Auñón-Chancellor, German ISS Commander Alexander Gerst, and Russian Sergey Prokopyev.

It is not clear how long the Soyuz vehicle will be grounded or how long the current crew can remain in orbit. NASA's own transportation system, the commercial crew vehicles under development by SpaceX and Boeing, have yet to take uncrewed test flights to the station, and those are unlikely to occur before early 2019. The first crewed flights would not take place until several months after that, unless the space agency is willing to take additional risks with those missions. China has a human space flight capability, but it has no crew missions planned before 2020, and NASA is barred by Congress from working with the Chinese Space Agency.

Recent problems

Several recent problems with the Soyuz launch system will complicate the investigation. In December 2016, a Soyuz-U rocket carrying an uncrewed Progress spacecraft laden with 2.6 tons of food, fuel, and other supplies lifted off from the Baikonur cosmodrome in Kazakhstan. Following a normal launch, first-, and second-stage firings, things started to go wrong for Progress MS-04 at about six minutes into the flight, also with a booster issue. The spacecraft was lost. The rocket that launched Thursday was a slightly more modern Soyuz-FG booster.

Moreover, there was a problem with the last Soyuz spacecraft, which launched in June, when a small leak was found in the vehicle's orbital module in space in August. Russian officials have been coy about what caused the problem, even intimating that a NASA astronaut may have drilled the hole while in space. An investigation is ongoing, but what most likely happened is that a worker accidentally damaged the spacecraft at some point during the manufacturing or integration process. This could have happened during the manufacturing phase at RSC Energia's facilities in Samara, Russia or at the processing and integration facilities in Baikonur, Kazakhstan, from where the spacecraft was launched.

In the wake of this most recent mishap, NASA released a statement just last week saying it had full confidence in the Soyuz rocket and spacecraft that was launching Thursday morning. NASA's administrator, Jim Bridenstine, was actually in Kazakhstan for the launch.

This story will be updated with additional information when it is available.