Gbaba Evaluation Committee
Tellesburg, Charis, August 2, New Terran Federation Year 2
Because of the tragic loss of Merlin, Nimue, and Owl in the closing actions of the Great War, limited data on the Gbaba and the old Terran Federation is available. While the urgent search for more old data stores continues, this document presents an initial analysis.
Known data at this time:
- Gbaba destruction of an alien race discovered 10 years before the destruction of Crestwell
- Crestwell located 50 light years from Sol and the newest and furthest human colony. It was probably founded before the finding of the destroyed alien race.
- Human interstellar colonization is estimated at 250 years.
- Crestwell attacked by a large fleet with no prior in system recon by the Gbaba.
- Initial course of the war involved the loss of 3 human major worlds (of 14), followed by a counterattack that took 6 Gbaba worlds.
- Next phase started with a massive fleet showing up and driving back to their major words. The Gbaba then besieged all of these.
- One attempted colony fleet made it past the Gbaba before Project Arc. It was destroyed within 10 years and warned that the Gbaba tracked their transmissions.
- The time from the fall of Crestwell to the final battle of Task Force 1 of Operation Ark was 43 years.
- Against the poor tactics of the Gbaba, human fleets could often handle 3 to 4 times their numbers.
- Gbaba ships appeared to be unchanged in 2,000 years and had slightly superior equipment. Their ships are generally 15% faster to their Terran counterparts.
- The Gbaba may have been able to track at least the initial direction of hyperspace travel of Terran ships because they were able to vector in on Terran fleets uncomfortably quickly.
- Operation Ark flew around 10 years from Sol. If detected it would have fled another 10.
Since we are currently ignorant of many basic data on the Gbaba-Terran war, we used the above data plus the following astronomical data to come to some assumptions on ship performance.
- Sol is around 27,000 ly from the center of a Galaxy that is 160,000 ly in diameter by 2,000 ly thick. There is a central bulge of around 10,000 ly in diameter.
- The density of stars is around 0.035 stars per cubic light year with an average of 6.59 ly between stars in the general neighborhood.
- 90% of all stars are main sequence. 42% of main sequence stars are type G or K. Initial sky surveys predict 11% of all G and K stars should have 1 to 2 Earth mass planets in the water zone of their stars.
The following derived assumptions that apply to all scenarios should only be considered as approximate.
The extent of the Gbaba colonization is extrapolated from Terra’s expansion to 50 ly in 250 years. Since the oldest Gbaba starship found is 2,000 years old, we can assume the Gbaba have been interstellar for at least as long. We assumed both expansions started with 6 ly radius spherical volume (slightly less than average distance between stars). Since the TF expanded to 50 ly in 250 years, the Gbaba, if they expanded at a similar rate, would have expanded to 100 ly in 2,000 years and 115 in 3,000. The TF encompassed around 1,833 stars with 76 planets of 1 to 2 Earth mass in the habitable zone of G or K class stars. On these potential planets 14 major colonies were established. The figures for the Gbaba after 2,000 years would be 14,660 stars with 610 Terra-like planets containing 112 major colonies. If the Gbaba had been expanding for 3,000 years the numbers would be 21,991 stars, 914 habitable planets, and 168 major colonies.
Note that the above analysis involved linear expansion functions. Exponential functions were investigated and yielded results that the Gbaba dominated the entire galaxy. This seems unlikely given their xenophobia. It seems likely if they were present in the entire galaxy any life bearing worlds would be investigated on a routine basis making Earth’s technical development very umlikely.
The endurance of starships is an important factor. We know Terran ships were capable of at least 10 years of continuous operation since that is the time taken to reach Safehold. We also know that another ten years of continuous operation is at least possible because of the emergency continuation orders for Operation Ark.
The question comes up why Ark did not simply go 20 years initially since doubling the distance from Sol would increase the Gbaba potential search area by 8. Furthermore if the Gbaba had found Safehold during the initial terraforming period, it is likely that they would find Ark again after another 10 year trip. There is likely some limit in the 20 year trip range.
The limit seems unlikely to be biological. 20 years of trip would have represented 30 years of life for the crew and cryo-sleep for the passengers before settlement. 30 years of life represents only around 10% of the life of the crew who were picked to be young. Cryo-sleep had only been used by the Federation for 30 or 40 years but was theoretically good for 1.5 centuries.
This means that the limit is probably represents a limit of fuel or maintenance. Ships under drive would need to be continuously operating their systems. This represents wear that could lead to a critical system failure. This is a totally different situation than long term storage of equipment seen in Niume’’s cave or minimum use scenarios seen in the orbital bombardment systems. Gbaba ships that are 2,000 years old probably represent ships activated from llong term storage an/or routinely maintained ships.
Limited data on TFN ship speed(and by default Gbaba ship speed by being 15% faster) makes any precise estimation difficult. The only direct reference to ship speed is that Safehold is thousands of ly from Sol. Other than that speed estimate depends on the speed of the detection of the failed colony attempt. Destruction of the colony within 1+ years by thousands of ships homing on the colonies signal seems to work best for the colony traveling out 1 or two years at 100 to 200 ly/y. However, the data is so sparse that any ship speed up to 800 ly/y can be seen as reasonable.
Both Crestwell and the failed escape attempt were apparently destroyed without Gbaba scouts entering into the system. This especially makes sense if the Gbaba have detectors that can detect high tech emissions at 6 ly or more. At 6 ly detection range the number of scouting parties drops by 40% compared to actually having to enter a planetary system. In general time to search a number of stars drops with the square of the increase in detection range.
The pace of the combat between the TF and Gbaba suggests that the Gbaba worlds conquered by the TF were 0.5 to 1.5 ship years from Sol. Closer than 0.5 it is likely that the Gbaba worlds would have been detected by the TF. Further away, the war would probably have taken longer. The committee is far less confident in the upper limit as compared to the lower limit.
The destroyed alien civilization found 10 years before Crestwell had no indication of interstellar travel. No known TF ship is known to have been in contact with the Gbaba before Crestwell. Thus, it can be inferred that the Gbaba conduct periodic sweeps for high tech civilization. Without ship speed, endurance, and detection range no reliable estimation of the size and frequency of the sweeps can be made.
However, the Gbaba could sweep out to 11 ship years every 500 years with 250 ships that do 115 ly/y. At 920 ly/y the Gbaba would need 1,725 ships. The following assumptions were used for the calculations:
- Gbaba sphere is 114 ly in radius and ships leave form edge
- Gbaba use pairs of scouts for sweeps
- Each scout can detect high tech emissions at 10 ly
- The pairs travel for 22 years
