BARD PAPER: GAIL4008

| Home | Traveller | BARD | GAIL |

---

Solar Powered Laser Carbine

by Antti Lahtinen

---

Since photovoltage cells transform a fraction of the incoming energy into electricity, I prefer to vary the energy output according to current conditions.

Photovoltage Cells:

Volume: 0.001 x area (for 1 mm thick photovoltage cell)
Mass: 2 x volume (silicon/GaAs substrate with transparent cover)
Efficiency: MIN(.5,0.02 + (0.06*TL-6))
Power: Eff x usable incoming energy
Price: Cr 1000 x area
Minimum area: ~ 1 mm2


TL	Eff
6	0.02
7	0.08
8	0.14
9	0.20
10	0.26
11	0.32
12	0.38
13	0.44
14	0.50

Notes: Cells are not very durable and must be attached to a suitable surface.

Cells are often armored with transparent cover to keep dust, sand, etc, from damaging the cells.

Since the photovoltage cells are quite expensive per unit surface, a solar cell array may consist of large solar collectors (lenses or mirrors) which concentrate the light to the cells. Some modern satellites have large lenses directly over the photovoltage cells so that the hardened lens is both armor and collector.

Example: TL-14+ photovoltage cell, 0.1 m2 area (20 x 50 cm)

Vol	Mass	Eff	Area	Price
0.1 dm3	0.2 kg	0.5	0.1 m2	100 Cr

In Terra the available solar radiation is ~1386 W/m2. However, due to atmospheric conditions a solar array can usually receive only ~1 kW/m2. The average output of the above photovoltage cell would be 50 W.

Solar-charged laser gun

The weapon contains only three moving parts: trigger, safety and battery cover. The squeeze safety is placed on the backstrap on the pistol grip and is automatically disengaged by the firing hand. Instead of a trigger guard, the weapon has large knuckle-bow which allows shooting while wearing mittens.

Inside the battery cover is a power connector which can be used to re-charge the battery with external power or fire the gun directly using any suitable power source.

Solar Powered Laser Carbine

Weapon Details

Tech Level: High Stellar (TL-14)

Weapon Type: 4cm DEI laser longarm

Pulse Energy: 15 kJ, required energy: 20 kJ

Weapon Length: 52.8 cm

Weapon Mass: 3.401 kg loaded, 2.846 kg empty, with no magazine

Weapon Price: Cr 639

Magaz Mass: 0.555 kg

Magaz Price: Cr 4.44 (100-shot box battery, 2 MJ total energy)

Features: bullpup stock, optic sight melee weapon frame, solar array

Name	ROF	DamVal	PenRtg	Bulk	Magaz	SS	Burst	S Range
5 kJ Laser	SA 5	6	Nil	3	100	None	None	300 (299)

Name	DV	(Pen)	Recoil	Range Bulk	TL	Mass	ExtMag	ROF	Magaz	Price
15 kJ Laser	6	(Nil)	None	300 m	3 14	3.4 kg	0.6 kg	SA 5	100	639

Notes: The weapon is covered with scratch-proof [1] photovoltage cells, which are used re-charge the magazine battery. When left on sun [2], the cells produce 50 W power[3]. One shot is re-loaded in 7 min 25 sec [4].

[1] Cells are covered with additional .5 mm transparent surface, and weapon is bought with "melee weapon" -class frame.

[2] A 0.1 m2 solar array is fixed on both sides of the weapon. When the weapon is placed on ground, either of the arrays is facing up. The cells produce 50 W for each kW of solar radiation.

[3] I estimated how large array fits by placing 10 x 10 cm paper squares on Valmet M-82 bullpup assault rifle.

[4] The loading time is for 1 kW radation. I assume that the battery has ~90% efficiency. When the array puts 50 joules in the battery every second, 10% of this energy is turned into heat and only 45 joules are later available from the battery.