The German astronaut Matthias Maurer has to wait for his start to the International Space Station ISS.

The 51-year-old Saarlander should start on Monday at the earliest (9:51 p.m. local time, 3:51 a.m. CET on Tuesday) together with three NASA colleagues from the Cape Canaveral spaceport in the US state of Florida, NASA announced on Thursday.

A final decision should be made in the coming days.

The “Saarbrücker Zeitung” had previously reported on the new start plans.

The start was originally planned for the last weekend in October and has already been postponed several times due to bad weather conditions, among other things. Most recently, NASA had targeted “Saturday at the earliest” (local time). For the first time in three years, a German astronaut is supposed to fly into space with Maurer. Together with NASA colleagues Thomas Marshburn, Raja Chari and Kayla Barron, he is to take off from the Cape Canaveral spaceport in Florida to the ISS space station. The four astronauts are to be transported by a "Crew Dragon" from Elon Musk's private space company SpaceX.

There are several things to consider when planning for Nasa, SpaceX and Esa: On the one hand, the weather conditions for a possible start on Saturday and Sunday (both local time) do not look good.

Both in Cape Canaveral and for the rest of the flight there are concerns about the weather.

Nasa also said it was not yet clear whether the weather could play along for a start on Monday.

The main concerns were strong winds in Cape Canaveral and poor weather conditions in the further course of the flight.

"Smaller, medical problem"

In addition, the "minor medical problem" will continue to be observed with a crew member because of whom the start had already been postponed once.

It is expected that this will be okay before the planned start, said NASA.

There was no further information on this.

There is also the "Crew-2" on the ISS, which has been there since April and should actually fly back to Earth soon.

These are the French Esa astronaut Thomas Pesquet, the NASA astronauts Shane Kimbrough and Megan McArthur and the Japanese astronaut Akihiko Hoshide.

A handover between "Crew-2" and "Crew-3" on board the ISS was actually planned.

The return of the "Crew-2" would be possible on Sunday at the earliest, otherwise also on Monday, according to NASA.

With both options, however, the "Crew-3" could not start on Monday (local time).

The time required between start and return - or the other way around - is currently still being calculated.

It must be decided whether the return of "Crew-2" or the start of "Crew-3" should have priority.

The "Crew Dragon" with which the "Crew-2" is currently at the ISS can officially stay in space for up to 210 days, possibly even longer after additional testing.

"Dynamic and complex decisions"

"These are dynamic and complex decisions that can change every day," said NASA manager Steve Stich.

"The weather can be particularly challenging in November, so our goal is to go ahead with the highest likelihood of mission safety and crew protection."

With the flight, Maurer would be the twelfth German in space, the fourth on the ISS and the first to fly there with a “Crew Dragon”.

On the ISS, the astronaut of the European Space Agency (ESA) will carry out numerous experiments for about six months at an altitude of around 400 kilometers and will probably also complete an outdoor mission.

The last time a German Esa astronaut was in space was Alexander Gerst in 2018.