Jessica Alba has defended the star-studded Blue Origin space flight amid a furious backlash.

The 43-year-old actress and entrepreneur took to Instagram to publicly defend the all-female voyage by resharing a post from political strategist Ana Navarro-Cárdenas, which encouraged critics to focus their energy on "denouncing" US President Donald Trump rather than the passengers.

In her post, Ana said: "I've seen endless criticisms of 5 women doing their space thing, I can't see how it affects our lives.

"I wish people would show same energy focus that anger towards fearlessly denouncing Trump's abuses of power, which do affect countless lives in the US and the world."

Jessica reposted the message and captioned it "this".

The all-female passengers on Blue Origin's 10-minute trip to space included Blue Origin founder Jeff Bezos' fiancée, Lauren Sánchez, singer Katy Perry, journalist Gayle King, film producer Kerianne Flynn, NASA rocket scientist Aisha Bowe, and civil rights activist Amanda Nguyen.

And, Gayle recently defended the trip after considerable backlash.

When asked about the criticism, Gayle told Extra: "I think it's good that we can really address it … because I was one of those people before I went on this flight and before I became educated. 'Why are we spending so much money on space when there's so much to do on Earth?' I was one of those people."

However, Gayle said she changed her mind after researching Blue Origin and finding out "what their intention is," which she said is "to figure out a way to harness the waste here and put it in space to make the Earth a better place."

Gayle added that "every time a flight goes up, they get some type of information that can be used for something else".

She went on: "So I wish people would do more due diligence. And then my question is, have y'all been to space? Go to space or go to Blue Origin and see what they do and then come back and say, 'This is a terrible thing.'"