Pre-pulsar spaceship

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Pre-pulsar spaceship
Pre-pulsar spaceship image
Pattern type Spaceship
Number of cells 128
Bounding box 73×14
Direction Orthogonal
Period 30
Mod 30
Speed c/5
Speed (unsimplified) 6c/30
Heat 131.5
Discovered by David Bell
Year of discovery 1998

Pre-pulsar spaceship (or PPS for short) is any of three different period 30 c/5 orthogonal spaceships in which a pre-pulsar is pushed by a pair of spiders. The back sparks of these spaceships can be used to perturb gliders in many different ways, allowing the easy construction of c/5 puffers.

The first pre-pulsar spaceship, the symmetric pre-pulsar spaceship (or SPPS for short, shown to the right) was found by David Bell in May 1998 and was based on the P15 pre-pulsar spaceship found by Noam Elkies in December 1997.

The asymmetric pre-pulsar spaceship (or APPS for short, shown below) was found by Alan Hensel, also in May 1998, based on a skewed version of the pre-pulsar.

The third period 30 pre-pulsar spaceship, shown below, is similar to the symmetric pre-pulsar spaceship but contains an extra T-tetromino between the spiders and is glide symmetric.

Martin Grant's 601-glider spider synthesis resulted in a 1212-glider synthesis for the symmetric pre-pulsar spaceship on March 8, 2019.[1]

Image gallery

The asymmetric pre-pulsar spaceship.
Download RLE: click here
The glide symmetric pre-pulsar spaceship.
Download RLE: click here


  1. Adam P. Goucher. Re: Small Spaceship Syntheses (discussion thread) at the forums

External links

  • 128P30H6V0.1 at Heinrich Koenig's Game of Life Object Catalogs