#### Weapon Arm

The first question is which weapon we want to mount. The list in Robots itself lists several, many of which aren’t available due to our tech decision, and many which either aren’t useful or are overpowered. THS instead shows two alternatives: the anti-materiel rifle (23lbs and 0.29lbs per shot, ST13, but 11d+1 damage), and the battle rifle (11lbs and 0.016/0.8lbs per shot, ST10, but only 6d although it mount a micromissile pod). There’s also the police grenade launcher from Robots, at 25lbs, which would be interesting. I’ll still prefer the other two. Which one, though? Why not both?

Specifically, let’s assume we’ll just produce a pod which can be changed in the field. The pod is 35lbs and has a volume of 0.7cf; per default it mounts a battle rifle, 500 shots (8lbs), and an additional 20 minimissiles. Note that you can trade off minimissiles and normal ammunition at 50 shots per missile. Cost is $2,056.20. For less subtlety and less flexibility, mount the AMR plus 40 shots (34.6lbs,$3,064.32; waste brings it to 35lbs). The modular socket costs $350. To fire that weaponry, the arm needs an ST of 13. I’ll take ST 15 for 1.4lbs and$3,000 base. Striker and retractable brings this to 1.05lbs and $900. Oh, and we’ll also need a sensor package - Telescopic Zoom 5 (32x), Deafness, and No Smell/Taste sound good and give 0.25lbs and$2,500.

### The Body

The arms already defined require 1.17cf. What else do we mount?

At the moment, this is a total of 30lbs, $1500, and 0.6cf. Since it’s four legs, each of those has 7.5lbs and 0.15cf. However, the whole drivetrain has to be 60% of the body’s volume (1.8498cf). We could move components into the legs, but fuel tanks seem kind of silly, so I’ll just add empty space to bring it to 1.85cf. That brings our whole robot to 4.933cf volume. #### Structure and Surface Features What are the surface areas? We already computed them for the arms (sensor arm: 1, weapon arm 5, manipulator arm 2.5); the body has an area of 18. Total is 30. Our frame will be extra-heavy, massing 60lbs and costing$15,000. Hit points are 12 (sensor arm), 60 (weapon arm), and 30 (manipulator arm) - the extra-heavy option really pays of here. Similarly for the body - hit points are 108.

Our armour goal, as previously mentioned, is 200DR; at the total area of 30, every point laminate armour DR costs 1.2lbs and $120. Turns out I greatly underestimated total required area - DR of 200 would be 240lbs and$24,000.

So, back to the drawing board. A 60° slope for the body from the front increases effective volume to 3.85375; total leg volume then becomes 2.31cf. This gives a total volume of 6.16375cf, area of 21 (total is 33) and therefore structural mass of 66lbs and costs $16,500. Body HP, by the way, becomes 126. Now, we’ll mount laminate armour worth 100DR: 132lbs,$13,200. From the front, that’s an effective DR 200.

What else? I dislike the chameleon systems, but an infrared cloak is extremely useful, and so would be radiation shielding. Also, sealing. That’s 16.5lbs, $2,475 for the infrared cloak, 16.5lbs and$165 for radiation shielding, and another $330 for sealing. Actually, let’s replace the IR cloak with IR/Stealth: 33lbs,$4950.

What else? Surface sensors would be nice, but $9,900 seem a bit high. I’ll leave them off. ### Statistics So, where does that leave us? • Design Weight: That’s 359.85lbs unloaded, and 409.85 loaded (0.205t). • Volume and Size: Total volume is 6.16cf; longest dimension is about 1.7 metres. • Price: The robot costs$97,930. That does not include the weapons pod.
• Attributes: Body ST is 64; arm STs can be found above but are 15 for the manipulators. DX is 10; IQ 8. HT is 12.
• Ground Speed: 1KW drivetrain divided by 0.205t and multiplied by the speed factor gives 13.25y/s as speed. That is slightly better than human world-class sprinter speeds. Luckily we over-provisioned the power system! Loaded, it cannot float; unloaded it does. In that case, it can swim at 3y/s.

Another attribute is required maintenance: Robots doesn’t include that, but Vehicles does (at 20,000/sqrt(cost)). This means a maintenance interval of 63 hours for our robot: Every 63 operating hours, it needs four hours of maintenance. This means a human mechanic could keep five robots operating continuously; if we assume maintenance being more automated, this could rise to maybe fifty.

#### Another Brain

But wait! THS has different computers. The closest equivalent to the 10lbs standard PC would be a 10lbs microframe, at $15,000 vs$10,000; plus the latter is already hardened. The THS one also has a higher complexity: 7 vs 5. Rebuilding the robot brain, we can mount a normal-sized microframe (10lbs, $10,000, 0.2lbs); with a DX+3 booster it’s$30,000. Since really exchanging that component would require me to recompute volume, armour etc, I’ll just leave it be.

This changes statistics: Cost is only $90,430 (without software), IQ is 10, and DX is 14. ### Software What kind of software should this mount? We’ll probably want Ambidexterity (C2,$10,000), Combat Reflexes (C4, $15,000), a Personality Simulation (limited, C4 and$8,000), and a Datalink (C1, $800). I’m ignoring the encryption program: That seems like it should be standard anyway. As for skills, there’s Guns (long-arm, subsuming the others as from the pyramid article), Soldier, Land Navigation, Tactics, Stealth, Electronic Ops (Comms), Camouflage, and Forward Observer. I’ll buy Guns, Soldier, and Tactics to 4CP (C4),$2,000 each. The others, I’ll buy at 2CP (C3, $1,000 each); note that I’m ignoring that physical skills are more expensive. That’s a total of$11,000.

This gives Guns-16, Soldier-10, Land Navigation-10 (although the inertial compass and GPS make this quite a bit higher in practice), Tactics-10, Stealth-14, Electronic Ops (Comms)-10, Camouflage-11, and Forward Observer-10.

Note that the software will probably be cheaper since the military probably doesn’t pay by license but pays for the development.

And there we go - that’s the robot!

## Summary

Compared to the RATS from THS, it is superior in almost every way: Far more heavily armoured (200DR vs 60DR), more and higher-powered weapons (usually a battle rifle and minimissiles vs a PDW and micro-missiles), and it only costs a quarter. On the other hand, the THS RATS can tunnel, has melee claws, and masses only half. Still, I’d definitely prefer the former.

Note that I might have redesigned it to mount a heavier weapon on the arm; the 15mm chaingun from Vehicles (p. 43, 16d, 51lbs and ROF of 20) would’ve made an excellent (extremely heavy) support weapon.

Despite their speed, they will probably be transported by another vehicle (which would also contain more fuel and ammunition), clamped to the outside. They are far more efficient to transport using spacecraft: You can fit 80 robots into the space occupied by one bunkroom (four people); mass-equivalency is 5 robots per bunkroom but does not include any equipment for the humans.

On a more meta-note, this took me quite some time to implement (probably about 3-6 hours). Part of it is my own inexperience, of course; I could probably achieve a far higher speed by writing a small program for that system. Might actually do that.

1. Note that this does not include armour which would make this quite a bit more weight.