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ELEVATOR going up. Next stop: geostationary orbit! The notion of a tether extending from the ground to space is not new: it was first dreamed up by Konstantin Tsiolkovsky, the father of rocketry, all the way back in 1895.

The space elevator is an appealing concept. It also seems impossible. No material we know of comes close to being strong enough to support its own weight over tens of thousands of kilometres. So the idea has never attracted serious funding: the writer Arthur C. Clarke once said it would be built 鈥渁bout 50 years after everyone stops laughing鈥�.

They haven鈥檛 stopped yet. But perhaps they should. Other implausible schemes are turning into engineering realities. Silicon Valley firms and entrepreneurs have started betting big on 鈥渕oonshots鈥�: grand projects that will be tough, if not impossible, to pull off, but which would have a huge impact if they succeeded 鈥� like the Apollo space programme, the original moonshot.

Google鈥檚 recent restructuring highlights this trend. The search firm is now just one of a family of enterprises targeting far-fetched objectives from driverless cars to longevity: its holding company Alphabet spent $3.74 billion on moonshots last year.

Is this money well spent? Debate has raged in business circles about whether Google鈥檚 founders have the moral right to spend their investors鈥� cash this way. Doubts may be assuaged by the promise of huge profits if any of these bets pay off. But what do the rest of us stand to gain?

鈥淭hese grand projects would have a huge impact if they succeeded, like the Apollo space programme鈥�

Well, there鈥檚 spectacle, for one thing. Elon Musk鈥檚 first attempts to show off his reusable rocket left sceptics laughing. But then it started working 鈥� not perfectly, but well enough to silence the laughter. That gives space flight fans something to root for, at a time when many governments seem to have lost interest (the ambassadorial residents of the International Space Station notwithstanding).

The cost of this spectacle is not fronted by the public 鈥� not via taxation, anyway, although subsidies are a different matter. The expectation is that 鈥渘ew space鈥� initiatives will mostly let the very rich work and play on the high frontier. But it could support the development of more public-spirited projects too.

For example, orbiting solar power stations are another good idea that have always seemed laughably difficult in practice. The plan is simple: harness the sun鈥檚 energy before it is dissipated by Earth鈥檚 atmosphere, then beam it down using microwaves, thus providing clean, abundant energy.

The obvious objection is the astronomical cost of lifting huge amounts of equipment into space. Reductions in the weight of solar technology have encouraged stolid aerospace and utility firms to experiment in earnest (see 鈥�Space solar: The global race to tap the sun鈥檚 energy from orbit鈥�); perhaps the space flight moonshots can help them out.

Some may yearn for the days when the military-industrial complex led the way. But now politicians are following the Valley鈥檚 rhetorical lead: last month, US vice-president Joe Biden proposed a billion-dollar moonshot to cure cancer, although he met with from .

We鈥檒l see if medicine eventually proves as receptive to moonshot thinking as engineering. Actually, we have yet to see if it can deliver a return on all those billions there, too. Let鈥檚 hope it can: combining big money and big dreams might finally get some 鈥渋mpossible鈥� ideas off the ground. Including, just maybe, a space elevator.

This article appeared in print under the headline 鈥淪hooting for the moon鈥�