Sunday, 3 March 2013

Tau Zero, Chapters 3-10

(Neat. This edition has the value of Tau on the cover.)

Have I correctly understood the Bussard ramjet and other cosmic events in Poul Anderson's Tau Zero (London, 1973)?

Ion drive moves the spaceship Leonora Christine out of Earth orbit. She starts to leave the Solar System in free fall. Spacemen detach the Bussard module from the back of the vessel so that it trails on a cable and stays on the same orbit as the vessel when the cable is reeled back in. The spacemen return to the vessel, which extends scoopfield webs and activates scoopfield generators. The webs deploy, across thousands of kilometers, magnetohydrodynamic force fields that lock the Bussard module into position. The star-drive engine starts.

The fields deflect dust and all gasses except hydrogen which they force around the vessel to the Bussard engine whose electromagnetic vortex fuses the hydrogen into a laser effect that moves the ship, which will accelerate away from Sol, then decelerate towards Beta Virginis.

Passage through a small nebula damages the decelerators which cease to function so that the ship accelerates uncontrollably. Spacemen can go outside to try to repair the decelerators. However, if the accelerators are not turned off, then their radiation will kill the spacemen and, if they are turned off, then radiation from the impact of interstellar particles, otherwise deflected by the fields, will kill them.

There are two possible responses to this situation:

(i) circle around within the galaxy for an estimated fifty years until the last crew member dies;
(ii) leave the galaxy.

To implement (ii), the ship will:

widen scoopfields and plunge through matter-dense galactic regions;
gain enough mass to utilize denser regions instead of being damaged by them;
spiral through the thirty thousand light year distant galactic centre and back out again into intergalactic space;
leave the local galactic cluster of Milky Way, Magellanic Clouds, Andromeda galaxy and thirteen other galaxies;
in inter-cluster space, where gas is almost nonexistent, switch off accelerators and hopefully repair decelerators;
travel to the forty million light year distant Virgo galactic cluster;
colonise a suitable planet in a galaxy of that cluster.

The discussions in Chapters 9 and 10 add no new crew member names but do mention M'Botu and Iwamoto who are as yet mere names.

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