Tellumo is the fifth planet in the Ciro system and a member of the Galilean Planets. It is classified a super-Gael, having 1.7 times the radius, 5.3 times the mass, and 1.9 times the surface gravity of Gael. Tellumo is one of only two planets, the other being Gael, that has either liquid water on its surface or Oxygen in its atmosphere. Although it is generally a cold planet, Tellumo undoubtedly has niches where life thrives.
"The concepts of identical and binary twins are far from foreign to kerbalkind. But to find this in Gael's shadow! Nothing could accelerate a space program more than the dream to land on a second planet that is safe to take off a helmet at and grill things for the crew. The one big problem, though, is all the gravioli."
- Deep Sky
Liquid water covers 55% of Tellumo’s surface, with 99% of it concentrated into two large oceans. The oceans are about equal in size and both are completely surrounded by a combination of land and polar ice cap. Although circumnavigation is impossible on Tellumo, it is possible to circle the globe by way of land and ice sheet. The remaining 1% of Tellumo’s liquid water is found in numerous inland lakes and rivers.
Land covers about 26% of Tellumo’s surface. It is mostly concentrated into one contiguous land mass that snakes around the planet. The land is generally high and rugged. Most coasts rise steeply as one moves inland from the ocean. About 90% of the total land area lies at elevations over 3,000 meters above sea level. There are two great mountain ranges that circle the planet, one centered on a latitude of 40° N, and the other centered on a latitude of 40° S. Tellumo has many mountains soaring to elevations over 12,000 meters, with the tallest peak reaching 13,361 m (53° 20’ 37” S, 125° 28’ 39” E).
Tellumo has two massive polar ices caps. Not only do they cover 19% of the planet’s surface, but they extend to heights exceeding 9,000 meters ASL. There could be as much or more water in Tellumo’s ice caps as can be found in its oceans. The ice caps cover nearly the entire surface at latitudes above 60°, with some of the ice sheet extending to nearly 30° latitude.
Tellumo has a heavy atmosphere with nearly 15 times the total mass of Gael’s atmosphere. It consists principally of nitrogen (74%) and oxygen (16%). Because of Tellumo’s crushing gravity, its atmosphere is greatly compressed. At sea level the pressure is 10 atmospheres, but this drops rapidly with increasing altitude. By an altitude of 2,230 meters the pressure has already dropped to 5 atm, and at the top of the tallest mountain it is a scant 6.4 kPa. Despite the atmosphere’s great mass, it extends to a maximum height of only 45 km above sea level.
Tellumo’s location 1.6 AU from the sun places it near the outer edge of the habitable zone. Consequently, its temperature profile makes it much colder than Gael. If not for the greenhouse effect brought about by its thick atmosphere, Tellumo would be a frozen world. The atmosphere is able to trap enough heat to warm the planet’s surface to a mean temperature 72°C above its black body temperature. This is just enough for Tellumo to support oceans of liquid water. Like Gael, Tellumo has a troposphere, stratosphere and mesosphere, though warming in the stratosphere is much less pronounced than it is on Gael.
Tellumo’s thick troposphere moderates temperatures so that the diurnal and latitudinal range of temperature is about half what it is on Gael. Sea level temperatures at Tellumo’s equator range from a low of 1°C at night to a high of 8°C during the day, while at mid latitudes the temperature is usually near or below 0°C. At the poles the temperature is -70°C, but this is in part due to the poles’ elevation of 9 km ASL. At the tops of Tellumo's tallest mountains, the temperature can fall below -80°C. The conditions here allow carbon dioxide ice to form.
Because of the cold temperatures, it is presumed that evaporation rates, and therefore precipitation, is low. What precipitation does fall does so mostly as snow. In areas where temperatures remain below freezing, principally at high latitudes and high elevations, the snow has accumulated to produce glaciers, which today cover a significant portion of Tellumo’s land area.
Although much of Tellumo’s surface is gripped in ice age like conditions, it is probable that in the ocean depths there is a considerable amount of ongoing geothermal activity, potentially producing warm habitats, and helping to keep the ocean from freezing.
Tellumo’s equator is inclined 1.5 degrees to its orbital plane, and its orbit is slightly eccentric. These characteristics give rise to a small seasonal temperature variation.
Tellumo is one of two planets having a ring system, the other is Nero. The rings extend from about 220 km to 755 km above Tellumo’s equator, with the inner half of the rings being significantly brighter than the outer half. There are two gaps in the bright ring, a small one at about 274 km and a larger one at 455 km. Inside the large gap orbits the small moon Lili. The source of the rings could be material shed from Lili, or perhaps debris from an ancient moon that was destroyed.
Aerocapture at Tellumo is possible provided entry speeds are not too extreme, the craft has a sufficiently low ballistic coefficient and adequate heat shielding, and the approach trajectory hits the narrow entry corridor. Plan carefully because Tellumo can be quite unforgiving of mistakes.
Atmospheric entry from low Tellumo orbit can be easily achieved with a properly designed entry vehicle, though heating and acceleration loads are much higher than what we’ve come to expect at Gael. Heat shields are recommended.
Parachutes work very effectively in Tellumo’s thick atmosphere, allowing parachute landings at even the highest elevations. Because air density is greater on Tellumo than it is on Gael, less parachute area is needed to attain the same descent rate.
Tellumo’s atmosphere possesses oxygen, allowing Whiplashes, Rapiers and any classical jet engine to function up to 20 km altitude. The use of hybrid and purebred scramjets as middle or upper stage engines on a craft is now a viable and very broad avenue for engineers to explore.
A craft launching from Tellumo must attain approximately 4,200 m/s orbital speed to secure a low orbit. However, because of Tellumo’s high gravity and thick atmosphere, expect significant losses. A sea level launch requires a delta-v of over 7,000 m/s. This challenge can be met using aerospike engines, but the maximum attainable payload fraction is only about 1%. By launching from an elevation of 2 km, an approximate 1,000 m/s reduction in delta-v is possible with a significant improvement in payload fraction.
Tellumo has 12 natural biomes:
- Inland Water
- Northern Range
- Southern Range
- Ice Caps
- Tellumo is akin to Eve, however, with realistic proportions it boasts 10 atm of pressure at sea level and 5 atm at approximately 2.2 km. And its atmosphere height is 45km, unlike the 90km at Eve.
- Tellumo's radius is 300 km greater than that of Eve. Instead of a tall atmosphere this provides the bulk of the challenge of returning to orbit from its surface.
- Being a Super-Kerbin/Super-Gael, Tellumo possesses Water and Oxygen, allowing jet engines to propel any sea-faring vessels, and allowing kerbals to swim. Hopefully they can.
- Abundant Karbonite in the crust, ocean and atmosphere enable deployment and practical use of Karbonite-powered booster stacks where this resource itself is a type of SolidFuel and is refillable and throttle-able in-situ unlike stock SolidFuel, and near-unlimited propulsion for low altitude flying vessels or oceanic vessels, undoing the constraints of requiring a heavy support craft to deliver a LiquidFuel supply, or for primary craft to drive ashore and search for Ore deposits.
- Salinity in Tellumo’s ocean may act as a natural antifreeze. The freezing point of Earth’s seawater is about -2°C.
- Tellumo is a very large solid body, but there is a moon even larger than it.
- Tellumo has a a space potato called Lili. It is even tinier than Gilly.
This planet carries one region flag.
- Al Tellum: Given its configuration and its proximity to Gael, Tellumo is considered a sacred world. It's easy for any and every amateur astronomer to catch this planet in their sights, but quite practically, only the best of the best can hope for the honor of landing here, and moreover, returning from here.