Kerbals are the native denizens of the planet Kerbin, and cartoonish in-game analogs for humankind.
Kerbals display no variance in height or weight. They stand roughly 0.75 meters tall (2'5½"). A Kerbal in an EVA suit has a mass of 93.75 kilograms (206.68 lb.), which is 0.09375 in-game Mass units. However, this only counts toward the mass of a craft if seated in an EAS-1 External Command Seat; Kerbals add no mass when in a command pod or PPD-10 Hitchhiker Storage Container or the Mobile Processing Lab MPL-LG-2.
The only Kerbals seen in-game work at Kerbal Space Center. Other than two official in-game characters, currently all Kerbals appear identical.
Kerbals have massive heads with respect to their bodies with roughly half of their total volume accounted for the head. Kerbal eyes protrude from their heads significantly, as do their corneas from the eyes. Kerbals appear to lack any irises, or they are perfectly black in color. They also possess no eyelids.
Judging by official artwork and in-game models, Kerbals appear to have two large teeth that span the length of their gums, one on the mandible and one on the skull.
Their skin hues appear to range from light green to pale green, if they range at all. Although Kerbals appear mostly hairless, they have notable hair growth occurring on the top of their heads and Wernher von Kerman can be seen to have a mustache.
Kerbals also appear to be warm-blooded, given their ability to sweat.
Kerbals have an awkward, sprawling walk due to their wide pelvis and short legs. A Kerbal's walking speed on Kerbin is about 0.87 m/s, it's running speed is about 2.35 m/s.
All Kerbals, or at least the ones involved with KSC, seem to be male judging from their names and general appearance. C7, a developer at Squad, has said that “there were no plans to add female Kerbals”. He also said that they don't have any specific sex in his mind. Maxmaps, a public relations manager, has repeatedly said on squadcast that female Kerbals, however, were in the plan.
Anecdotal statements in the descriptions of the Rockomax HubMax Multi-Point Connector and the RoveMax Model 3 suggest that Kerbals may die from shock when exposed to unexpected technological innovations. This could also be marketing hyperbole.
Kerbals seem to be in infinite supply, the in-game description of planet Kerbin saying its conditions support a "seemingly undepletable population of the eager green creatures".
Their most prominent personality traits are their Stupidity and Courage, as these are about the only individual traits to be seen beyond a name. Some Kerbals, such as Jebediah Kerman, have the rare "badass" trait, which makes them continually enthusiastic and without fear.
Kerbonauts can be seen to spend years in space without showing any signs of muscle atrophy or other ill effects and can survive for years with vastly less food and oxygen than humans would require. There are various theories why this is possible:
- They may enter a state of hibernation to endure long space travels
- This is unlikely, as they appear always awake when controlling the craft (although they still might hibernate whenever their ship isn't active).
- Their green skin may contain chlorophyll allowing them to photosynthesize
- Unlikely, as Kerbals can also survive without light seemingly indefinitely.
- They may also not need oxygen to breathe, as they have no nose and can survive with their mouth closed. Although the question arises how Kerbals get energy.
- Kerbals do eat, but life support simply has not been implemented into the game.
- Another theory simply states that worrying about life support might simply not be considered fun.
Kerbal eyes may be a vulnerable spot for injuries due to protrusion, size, and lack of eyelids. If Kerbal eyes truly lack irises, their eyes would be very sensitive to bright lights.
Kerbals' awkward, sprawling walk may indicate that their species only recently evolved to the point of bipedal movement.
Kerbals only speak in some recent trailers but not in-game. In trailers they speak reverse Spanish (aka "hsinapS"). However, Wernher von Kerman and Gene Kerman do emit sounds like "a-ha" and disappointed groans during in-game tutorials. They seem to write in modern English.
All kerbonauts have a random generated first name and "Kerman" as the surname. The first name is either a combination of phonetic syllables or chosen from a list of preset names. There are also a few uniquely named Kerbals, most of whom are apparent homages to real-life figures in NASA.
Kerbals refer to their species as "Kerbalkind" in several in-game texts. This parallels with the real-life term "mankind" or "humankind" English-speakers use.
Kerbal larynxes would need an interesting structure to be able to pronounce phonemes that humans either cannot or would at least have great difficulty pronouncing. In addition, their language is full of sudden sharp sounds, unmelodic syllables, and impressively difficult pronunciations, owing to its nature of being a reversed human language. Given the cartoonish nature of Kerbals, their language may "simply be" without any realistic explanation for their vocal abilities.
Material culture and technology
Limited observations make things difficult to determine.
The technology and architecture appears to share many similarities with the modernized nations of Earth during the 1960s-2000s. However, currently (0.23[outdated]) Kerbin has no cities, homes, or any buildings other than those related to aerospace (barring a few easter eggs). The text for the EVA Report while flying in the lower atmosphere over Kerbin's Grasslands biome, however, mentions being able to "see my house from here", implying that Kerbals may live in houses visible above ground even though they are none to be seen in-game yet.
From the humorous descriptions found in-game, it can be assumed that Kerbals are even more foolish and accident-prone than humans. Kerbals have accidentally mistaken planets for dust or smudges on a telescope lens or mistaken how telescopes work entirely.
A necessarily short list of technologies Kerbals possess includes
- Liquid-fuel and solid-fuel engines
- Electric power generation and storage
- Radio communications
- Steel and concrete building construction
It appears that their culture revolves singly around the process of designing, building, launching, and riding rockets and planes, as every structure on Kerbin (excluding a certain Easter Egg) is devoted to either aviation or spaceflight.
One explanation of the scarcity of buildings on Kerbin theorizes that Kerbal civilization may live underground, or underwater, due to some unknown factor. Of course, this may be because KSP is a game that does not necessarily mandate cities, or they are planned but not yet implemented.
Some theories state that Kerbals, if their anatomy and biology resembles plants, can be cloned. This idea could be supported by the fact that all Kerbals have the same surname, and that all of them look alike but have different personalities via artificial memories, meaning that all of them are clones of one original Kerbal with “Kerman” as the surname. This could possibly be Jebediah Kerman, since the "Selection Process" labeled him as #0001. Also, it could be supported more by the fact that at least some Kerbals, Jebediah, Bill and Bob, can respawn or un-die.
- Kerbonaut, the only Kerbals playable in-game
- Jebediah Kerman, kerbonaut, badass, and manufacturer
- Bill Kerman, kerbonaut
- Bob Kerman, kerbonaut
- Wernher von Kerman, famous rocket scientist
- Gene Kerman, flight instructor
- Dinklestein Kerman, manufacturer
- Dawton Kerman, swimming pool supplier
- Bobak Kerman, mission controller (semi-official)
- Kirrim Kerman, kerbonaut, special agent (semi-official)
- Answer by C7 in Kerbal Polar Expedition - Day 5 - Part 1 (Charity Water Campaign) by HOCgaming at 1:14:13