Date: 20710601

Classification: Secret

Circulation within TVOR-nets only.

Priority: Executive Summary for ICCXD

Sources: Collated by Profoundity from science team data (reports MICH 12-153)

Subject: On the Petra Findings

Petra (DM+46 1797 A21)

Petra was found to be a metal-rich asteroid in the Oort cloud of DM+46 1797 system [Orbital Elements and data enclosed], roughly 5 times 4 kilometers across. Astrographic data suggests that it has had a stable orbit for at least one billion years, with a major collision with another body approximately twenty million years ago which created the system of rifts near the east pole.

Studies of the surface revealed traces of activity, tracks from machines and the hidden entrance to the labyrinth. The entrance, a square hole 20 meters across at the bottom of a crater near the west pole, was surrounded by 5 meter walls of regolith rubble (note: no trace was found of the rock that had been dug out from the labyrinth. It may have been ejected into space).

The Labyrinth

The Labyrinth is the largest artifact found so far, a system of branching tunnels at least 20 kilometers in length extending from the entrance into Petra.

Beyond the entrance lies a conical chamber, 150 meters high and 100 meters wide. On the walls were affixed metal rails, suggesting a system for anchoring cranes or other equipment. The chamber floor was slightly radioactive, likely as a result of nuclear exhaust from a fission drive.

From the conical chamber three tunnels, each 3 meters in diameter leads away. Each ends at a pressure door; in tunnel 1 the door was open while in tunnel 2 and 3 they were closed. The latter tunnels lead to what appear to be minor storage areas for tools, robots and ore. Tunnel 1 passes through and airlock and continues into the Labyrinth proper. Signs suggest that it was opened sometime in the past and the Labyrinth was depressurized; the exact amount of matter vented is uncertain, but likely on the order of 200,000 tons given estimates of the Labyrinth size, likely air-water mixture and the erosion of the walls.

Of special note is the ice sector, the sector beyond the airlock in tunnel 1131221212. This sector of the Labyrinth was not depressurized, and its water contents froze sometime after the abandoning of Petra. Judging by the finds of the cone (see below), the pit chamber (see below) and the reactor (see below), it was a central part of the Labyrinth. Unfortunately it has not yet been excavated completely.

The Tunnels

The tunnels have been dug using some kind of drilling equipment, leaving very smooth but irregular basic walls. In most parts of the complex the walls have been covered with regocrete, a concrete- like substance derived from pulverized regolith. Under this layer cables, antigravity modules and metal plates of unknown purpose have been found, while the regocrete usually have been decorated with elaborate patterns.

The Labyrinth is a branching tunnel system with no up or down. No tunnels form closed loops, all seem to diverge towards veins of ore. As a naming system each tunnel have been given the number of its "parent" tunnel and an unique identifier based on which branch it is from it (branch 1 of tunnel 1 is tunnel 11, its third branch is 113 and so on). From the tunnels irregular chambers have been dug out (numbered by the tunnel and in what order they appear, such as 113-5). In many cases working names for the different parts of the Labyrinth have been invented based on local textures, such as the "ridged sedimentary sector", the "fishbone sector" and the "encyclopaedia tunnels" (the later contain dense text-like inscription with a regular pattern of quasi-repetitions).

"Mining tunnels" do not appear to be as carefully decorated as the others. Their chambers appear to have been primarily ore sources and usually lack regocrete walls. The "living tunnels" are smaller (2-1.5 meter in diameter), covered with regocrete with elaborate inscriptions and contain numerous chambers with regocrete walls with inscriptions.

It is noteworthy that very few objects affixed to the walls have been found. Most were a kind of screw made out of titanium alloys that may have acted as hooks. It seems likely that objects were either freely drifting (as evidenced by the occasional scratches and dents in the walls) or affixed using now gone adhesives.

The "Pit Chamber" (1131221212-17) in the ice sector appears to be unique so far. It has five pits in its walls, each measuring around 1 meter across and 1.5 meter seep, with screws affixed around the opening. The walls are covered with textual symbols, which recur at different places in the Labyrinth. It is not clear what it was used for, although the screws seems to suggest that something was anchored above or in the pits. It has been proposed that the chamber was used as a nursery, rest room, religious place, sick bay, storage chamber or meeting room.

The Doors

In several places pressure doors can be found. These doors consist of three titanium wedges, able to draw back into spaces in the wall. The mechanism consists of sheets of memory metal (a titanium- nickel alloy) which change shape when heated by electricity. Each heating moves the doors (each wedge weighs around a half ton) from the current stable state to the other (open/closed). No moving parts exist except the doors themselves.

How the doors were controlled is unknown (see below).


Throughout the Labyrinth electricity has been transmitted using gold cables beneath the regocrete. They appear to have fueled the doors, antigravity modules, metal plates and likely acted as a medium for signaling; the exact system is uncertain, pending excavation of the ice sector.

The antigravity modules found in the walls and robot are conical, 10 centimeters long and 10 wide, made out of semiconducting silicon with a layered structure, with a single metal pin running through their length. Using unknown physics these devices apparently produced significant antigravity; the conditions under which this happens have not been replicated but seems to suggest electrical current and possibly other factors. They appear to have produced localized inhomogeneous fields, possibly of use in air- water filled tunnels.

The plates consist of plates of gold foil embedded in the regocrete, with no obvious connections. Their locations often coincide with kartouches. One theory is that they act as induction plates for interfacing with the electrical system, thus controlling the doors. It is not ruled out that the electrical system acted as a broadcast message medium, although the evidence is scarce.

In the frozen sector a large (4 meter diameter, see appended pictures) thorium nuclear battery was found behind an airlock in an air atmosphere (composition appended). The nuclear batter was estimated to have an output in the megawatt range during its original operation period, but is at present locked in a storage-state using neutron absorbers.

Organic Data

The ice of the ice sector contained biological matter, likely remains after decay processes after the abandonment of Petra but before the water froze.

The organics found (see appended file) belonged to the categories simple low energy compounds (typical for the decay of all known carbon-based life), common biomolecules (amino acids, saccharides, polycarbons and heterocyclic compounds) and complex biomolecules. The last category included protein-polysaccharide complexes of a completely new kind, and hydrophobic gel-like structures of branching chiral fatty acids. While similar on a basic level, the alien biochemistry was likely extremely different from terrestrial biochemistry.

No remains of organisms were found in the ice, which suggests that they are extremely sensitive to low temperature disruption. Some fragments of membrane-like polysaccharides were found, but their function remains conjectural.

The Inscriptions

The Petra inscriptions remain a mystery. Practically all walls have been engraved with complex patterns, ranging from wavelike to scales to geometric, occasionally broken by "kartouches" of what appears to be writing; some tunnels are covered in this writing-like patterns.

All inscriptions are around 0.5 cm deep and wide with minor variations. They appear to have been engraved with a vibrating conical instrument soon after the regocrete was set.

The textlike pattern consists of only 8 basic symbols, combined with their mirror images. Of these 8 basic symbols, only four ("branch", "arch", "bend", "straight") occur inside "words", the other four ("loop", "hook", "horns", "tail") occur around spaces. The writing appear to follow the direction of the tunnel in most cases (one instance of looped writing has been found in tunnel 1114), often in several parallel lines.

Linguistic analysis has suggested that there exists repetitions and correlations reminiscent of a syntax, but that spaces may not be significant delimiters. This last fact is very significant, since it suggests a radically different psychology than the human psychology where gestalt is important and a delimited object is seen as independent. Different sequences of figures seem to recur in correlation with each other, including some fairly long sequences. When written in several parallel lines the different lines show slightly different linguistic frequencies and syntaxes.

The Cone

This object was found in the frozen section. It is a aluminum cone, 15 centimeters long and 3 wide with a ridged surface. The base is open, and the interior is partially filled with a clear epoxy-like polymer (see appended analysis and picture). The hole in the polymer is roughly conical, with a shape that suggests an organic structure.

It is worth noting, given the speculations about aliens with a radar sense, that the epoxy matrix, while insulating in itself, has been doped with metal to make it conducting.

The purpose of the cone is not known, although it has been conjectured that it is some kind of tool.

The Robot

Several trails, around one meter wide, in the regolith on the surface emerge from the opening of the Labyrinth. A crater count combined with a planetological survey suggests that they are at least 6000 years old. They appear to have been made using an antigravity vehicle of some kind which has rearranged the gravel.

The robot was found in a crevasse near the east pole and is likely of the kind that caused the trails. It is a sphere (radius 65.4 centimeters) of polished titanium, with four arms (each 1.23 meters long) extending through holes in the spherical shell. It was found wedged into a crack, perhaps due to a malfunction.

The arms were singly jointed, ending in conical manipulators with radar antennas at the "wrists". They were actuated using titanium-nickel memory metal fibers. It seems that they were rather slow (2 m/s) and not very strong; this suggests that the robot was a sampling vehicle. The radar consists of a central sender module in the body and receivers on the arms; the resulting reflected signal was apparently sent back essentially unmodified.

The interior of the shell consists of a small thorium battery using a very complex sandwiched structure, a block of silicon-based electronics, actuator threads and a nest of conical antigravity units of the same kind as found in the walls. The electronics appears to be pulse-modulated and three-dimensional. Signals were sent back essentially unprocessed to a receiver somewhere; it seems likely that it was some kind of telepresence system sending back radar impressions.


The age of the Petra complex suggests that this is either a different species than the enemy, or that they have been present in the periphery of human space for a very long time. At present no conclusion can be drawn.

Overall, the technology gives a rugged, very practical impression. At the same time the antigravity modules are utterly incomprehensible and a paradigmatic shift away from current designs.

Why the asteroid was abandoned is unknown. It has been suggested that the inhabitants were nomadic and left as soon as they had enough supplies, or that it was built as a reserve bunker in case of war. The almost extreme absence of remaining objects is hard to explain; the asteroid may have been plundered (but in that case with extreme care) after being abandoned. This could have coincided with the depressurization.

There is evidence that the builders were aquatic or semi-amphibious (water and ice presence, hydroxide remains in the tunnels etc) and used an oxygen-carbon dioxide atmosphere. Beyond that very little can be said, except for guesses at their biochemistry and body size.

Petra remains a mystery. Who the builders were, what they were and what they did is shrouded in mystery, made even more opaque by the extreme lack of artifacts. The whole asteroid may have been fine-combed for objects (using the robots?) but why?

Report Ends

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