SpaceX's all-civilian Inspiration4 crew spent their first day in orbit conducting scientific research and talking to children at a pediatric cancer hospital, after blasting off on their pioneering mission from Cape Canaveral the night before.

St Jude tweeted its patients got to speak with the four American space tourists, "asking the questions we all want to know like 'are there cows on the Moon?'"

Billionaire Jared Isaacman, who chartered the flight, is trying to raise $200 million for the research facility.

Inspiration4 is the first orbital spaceflight with only private citizens aboard.

Earlier, Elon Musk's company tweeted that the four were "healthy" and "happy," had completed their first round of scientific research, and enjoyed a couple of meals.

Musk himself tweeted that he had personally spoken with the crew and "all is well.

Verifying that a satellite will resist the sheer noise of the rocket launching it into orbit is a very important test that every mission must successfully pass.

"Typically satellites are tested inside purpose-built reverberant chambers, such as ESTEC's own Large European Acoustic Facility sometimes described as the largest and most powerful sound system in Europe," explains ESA test facility expert Steffen Scharfenberg, overseeing the test campaign together with ESA mechanical engineer Ivan Ngan. A very powerful noise generation system produces a uniform noise field thanks to the reverberation on the thick concrete walls of the chamber.

ESA has initiated a working group comprising of European spacecraft testing entities, industries and academics to study an alternative method, in which the satellite is surrounded by less powerful noise generators but these are placed very close all around the satellite. This method is called the Direct Field Acoustic Noise Test.

This technique is already in use in several locations but there is not yet much experience of it in Europe. Accordingly ESA has just completed a test campaign where the classic method and the new method have been used on a small satellite to compare their results.