Yeah, I miss my old Heath "Tunnel Dipper". Wish I'd never sold it.

How many devices used tunnel diodes?

I'm Gunn look it up

Of course, the shielding depends on the stability of the earth's magnetic field.

Do you mean a steak and kiddley pie, or more a pork pie?

No one commenting on the so-called nuclear Verne gun?

It might be the only option to save hundreds of millions of lives on earth, the anomalies of earth magnetic field that have been detected by satellites might mean the overdue reversal of our protective field is imminent (within a century) which from history would take a few thousand years to stabilise.

The ability to launch thousands of tons of matter into space, quickly and even more economically than the BFR will allow enough material to build an artificial protective magnetic field in space and if we can mass produce strong enough fibres the famed space elevator, as well of course for cheaper space habitats.

The name nuclear puts fear in people but the small increase of radioactivity that might get into the atmosphere would be considerably less then that released every week by the use of fossil fuel, less if we use laser-initiated fusion explosions.

Blasting things straight up at escape velocity would not be very useful, however, there is a trick the early Apollo spacecraft used, that is to use the moon's gravity to return the payload back into the vicinity of earth.

Even if the magnetic anomalies are just (hopefully) a false alarm the nuclear gun will be built but just not by a very democratic country.

Well, an equatorial launch site might be better for a lunar gravity assist but the EU does have some strange form of democracy.

If the volcanic island of Ascension is stable enough it could be built there.

The project could be very helpful to mankind or extremely divisive, you choose.

Mass in space might be needed quickly if we do need an artificial magnetic shield.

The Japanese are very keen on a space elevator but unfortunately for them have no expertise in fusion bombs but would happily pay for cheap access to space.

The Apollo spacecraft had very primitive computers but managed to use lunar gravity assist to get back to earth. once a nuclear shell has gone around the moon a couple of BFR launched craft could attach to it to adjust its trajectory to that required if it cannot do it itself.

Of course, plenty of computer simulations would be needed to optimise everything.

Isn't all of our solar power beamed from space?

Is China's space laser for real?

https://www.popsci.com/china-space-laser