Steven Weinberg takes issue with manned space flight because it is expensive. Manned space crafts are being build to send astronmers to the space station and moon; and then Mars (estimated to cost 170-600b$, but Weinbrg thinks it'll cost over a trillion dollars given how we've underestimated things in the past). In contrast, sending Spirit and Opportunity to Mars only costed us 820m$ (1 thousandth of the cost). This is because inclusion of people make any space mission much more expensive (as they need food, shelter, air, water, etc.,).
Most of NASA's actual science has been done in unmanned missions (eg. studying CMR from unmanned satellites). Putting humans in space doesn't give us any scientific benefit that unmanned missions cannot (except learning about how to keep humans alive in space).
But wouldn't space travel motivate young scientists? None of the physicists Weinberg met were inspired by spaceflight. Most people are motivated from actual science. But doesn't it help us learn to keep humans alive away from earth? We haven't figured out a way to keep people alive on Antartia, maybe we should figure that out first.
In 1911, Rutherford identified the atomic model with the help of one postdoc and one undergraduate; supported by a grant of 70pounds. To learn more about the atomic model at a higher resolution, we need to break the nuclei by bashing them at high energies. This was done by a group of physicists at Berkeley using the cyclotron in 1930. In 1959, a higher energy Bevatron was invented to create antiprotons. But it found 100s of other unstable particles including antiprotons; more work made it clear that we need higher energy accelerators to learn more. Then more labs were built, notably in LHC at CERN near Geneva with it's circumference in miles. People were hoping to discover Higgs boson, and they did. Seems like this trend is going to continue for new discoveries.
In 1980s, US began plans for an accelerator 3 times the power of LHC; but it has been squashed in later years after the project started. Weinberg isn't too hopeful that this will happen.
While we can still study other aspects of nature without building accelerators, it might drastically slow down when we'll understand nature. The problem with big science is dropping the funding from 33% to 22% halts progress, building an accelerator half the size doesn't help.
Same with astronomy, we needed more powerful telescopes over time. Now, we need telescopes on satellites -- something that individuals cannot afford. Funding will now be the limiting factor to do science.
The population, especially in the US, has been becoming more and more skeptical about science.
People have a false notion of science. They imagine a science establishment that supresses dissent which only changes it's dogma after years of evidence to the contrary. They quote historical stories of lone scientists proving the establishment wrong, but such stories are rare. The establishment is generally shown to be right.
They would say scientists are wrong on the model of nucleus until 1932, universe expansion until 1998, etc., But these incorrect ideas were never held as dogmas, they were only tentatively held and the scientific community was quick to correct the concensus without the intervention of skeptical outsiders. It's every scientists dream to show the establishment wrong; hasn't always been true but this is true for a while now. It is foolish to bet against the judgment of science when the planet is at stake (climate change).
Additional reading:
- Third thoughts.
- https://www.nybooks.com/articles/2004/04/08/the-wrong-stuff/