Fusion SpaceMuster

Motor-hardware compatibility for high-power rocketry

J320-LR

721 N·s · 335 N avg

Loki Research · class J · Loki Red · delay 5, 8, 10, 14 s · built for the 38/740 case

406 mm long · 752 g loaded · 372 g propellant

TRA certifiedOut of production
Open in the interactive toolFind it in stockView on ThrustCurve

Muster is a shopping aid, not an assembly guide. Build only to the reload's printed instructions — always the authority — and confirm every part with the manufacturer before you buy or fly.

What you need to fly it

The simplest build — in its own 38/740 case. Reusable hardware you buy once, plus the single-use reload.

Reusable hardware to own

Single-use reload to buy

J320-LR reload kit

Single-use: liner, propellant grains, o-rings, and the delay or smoke element (the nozzle and closures are reusable, not in the reload), and ejection charge

Source: thrustcurve.org

  • This reload is out of production. That is not the same as decertified — it stays flyable until stocks run out — but it may be hard to find.
  • Loki's graphite nozzle is reusable and sold by throat number — the correct throat for this reload is in its instructions, and the wrong one can cause a failure.
  • A dab of high-temperature o-ring grease is needed on assembly (it comes with most hardware sets).

Cases that fly it

Its own case is the simplest; a longer case flies it too, with the adapter and spacers.