Heavyweight spaceship
Heavyweight spaceship  
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Pattern type  Spaceship  

Family  XWSS  
Number of cells  13  
Bounding box  7 × 4  
Frequency class  15.7  
Direction  Orthogonal  
Period  4  
Mod  2  
Speed  c/2  
Speed (unsimplified)  2c/4  
Heat  19  
Discovered by  John Conway  
Year of discovery  1970  
 
 
 

The heavyweight spaceship (commonly abbreviated to HWSS) or (rarely) big fish is the fourth most common spaceship after the glider, lightweight spaceship and middleweight spaceship. It was found by John Conway in 1970 and travels at a speed of c/2 orthogonally. Its domino spark can be used to stabilize several tagalongs, including sidecar and half of x66. It is one of only three known spaceships that is a polyomino in any of its phases.
Construction
In 1973, Douglas G. Petrie made the first 8glider synthesis for a heavyweight spaceship, involving a 3glider ship, a 2glider eater 1, and three other gliders from different directions in the final step.^{[1]} Later, a headon 3glider collision producing a clean HWSS was found by Dave Buckingham.^{[2]}
A number of different known ways to construct a heavyweight spaceship can be found in Mark Niemiec's glider synthesis database.^{[3]}
There are fourobject oneglider seeds for the HWSS, consisting of a loaf, a beehive and two blocks.^{[4]}^{[5]} There are also three 1G seeds for the heavyweight spaceship in the octo3obj database.^{[6]}
3G synthesis for the HWSS (click above to open LifeViewer) 
Commonness
 See also: List of common spaceships
The HWSS is the thirtyfifth most common object on Adam P. Goucher's Catagolue.^{[7]}
It is the fourth most common natural spaceship, being less common than the middleweight spaceship but about 355,000 times more common than MWSS on MWSS 1.
There are 26 results in the octohash database, 322 results in the octo3obj database,^{[note 1]} and 30 threeglider collisions in the octo3g database with at least one escaping HWSS.
Interactions with other objects
The side and tail sparks allow an HWSS to make changes to other objects without being affected itself  a "Heisenburp" effect. For example, gliders approaching from behind can be deleted in five different ways, or can be converted into a block, Bheptomino, or beehive, that can be reanimated to make catch and throw technologies, as shown below.
First row: the five ways to delete a forward glider with an HWSS. Second row: three HWSS Heisenburp reactions with a forward glider (click above to open LifeViewer) RLE: here Plaintext: here 
Two HWSSes can escort XWSSlike objects that would otherwise be unstable, forming a c/2 spaceship. Two similar examples are shown below.


Gallery
Three heavyweight spaceship eaters. The second one is honey bit and the third killer toads
Notes
 ↑ There are two collisions (headerless RLEs are 10b3o$6b3obo$11bo$2o$2o7bo$9bo$9bo! and 10b3o$6b3obo$11bo$2o$2o$8b3o!), both converging to the same sequence, with two escaping heavyweight spaceships. The final population is 425.
 ↑ according to Mark Niemiec: https://conwaylife.com/ref/mniemiec/flotilla.htm#ss3c
See also
 Fake xWSS
 Lightweight spaceship, Middleweight spaceship
 LWSS on HWSS 1, MWSS on HWSS 1, HWSS on HWSS 1
 Overweight spaceship
 Heavyweight emulator
 Ellison p4 HW emulator
 Ellison p4 HW emulator hybrid
 Heavyweight volcano
References
 ↑ Robert Wainwright (June 1973). Lifeline, vol 10, page 5.
 ↑ Robert Wainwright (September 1973). Lifeline, vol 11, page 18,19.
 ↑ The 1 thirteenbit spaceship at Mark D. Niemiec's Life Page (download pattern file: ss/13hw.rle)
 ↑ Extrementhusiast (June 24, 2013). Re: Blockic Seeds (discussion thread) at the ConwayLife.com forums
 ↑ knightlife (June 28, 2013). Re: Blockic Seeds (discussion thread) at the ConwayLife.com forums
 ↑ Dave Greene (October 21, 2022). Re: Octohash fingerprints (discussion thread) at the ConwayLife.com forums
 ↑ Adam P. Goucher. "Statistics". Catagolue. Retrieved on June 24, 2016.
External links
 HWSS at the Life Lexicon
 Heavyweight spaceship at Adam P. Goucher's Catagolue
 13P4H2V0.1 at Heinrich Koenig's Game of Life Object Catalogs
 Patterns
 Patterns with Catagolue frequency class 15
 Natural periodic objects
 Spaceships with 13 cells
 Periodic objects with minimum population 13
 Patterns with 13 cells
 Patterns found by John Conway
 Patterns found in 1970
 Patterns that can be constructed with 3 gliders
 Spaceships
 Spaceships with period 4
 Orthogonal spaceships
 Spaceships with speed c/2
 Spaceships with unsimplified speed 2c/4
 Spaceships with heat 19
 XWSS variants
 Spaceships with mod 2
 Polyominoes
 Glide symmetric spaceships