HX-5 is one of the twenty systems charted by Taisa Hanako while she commanded the YSS Elfin Princess in YE 30. It is an unusual system because it has two stars.

In YE 32, YSS Eucharis placed an Orbital Geological Survey Platform in orbit of a habitable moon of the system's gas giant. This effectively served as a claim to the system and helps define Yamatai's southeast border (YSS Eucharis Mission 11).

After a rescue mission to Mitsuya System the heavily-damaged Eucharis stopped at HX-5 to recover (YSS Eucharis Mission 15).

In YE 42, something or someone attempted to board the survey platform and its anti-tampering deteactors activated its self-destruct system¹⁾.

• Type F5 V Yellow-white Main Sequence
• Radius 9.01 x 10⁵ km (1.29 x sol)
• Mass 3.34 x 10³⁰ kg (1.68 x sol)
• Temperature 6700 K
• Luminosity 1.94 x 10²⁷ W (5.07 x sol)

• Type Jovian Planet
• Orbital Radius 4.83 x 10⁷ km (0.32 AU)
• Period 1.24 x 10³ hours (0.14 earth years)
• Gravity 41.18 m/s² (4.21 x earth)
• Special Planetary rings, 14 small moons, 4 large moons

• Type M6 V Red Dwarf Star
• Distance 1.80 x 10⁸ km (1.21 AU)
• Radius 2.76 x 10⁵ km (0.40 x sol)
• Mass 5.81 x 10²⁹ kg (0.29 x sol)
• Temperature 2400 K
• Luminosity 2.05 x 10²⁵ W (0.05 x sol)