| AG / SG |
Artificial gravity / spin gravity (mikelepage's preferred term) |
| Barbell, dumbbell, baton, bola |
Two masses joined by a rigid structure (barbell/baton) or a tether (bola), spinning end over end |
| "Tumbling pigeon" |
A single long vehicle (e.g. Starship) spinning end over end (Paul451) |
| "Hotdog" spin |
Spin about a vehicle's long (minimum-inertia) axis |
| Torus / wheel |
A ring-shaped habitat; "squorus" = square-section torus |
| Intermediate-axis (tennis-racket, Dzhanibekov) instability |
Rotation about the middle principal axis is unstable |
| Long-axis instability |
A slow drift from minimum-axis to maximum-axis spin through energy dissipation |
| CoM / CoR |
Centre of mass / centre of rotation |
| L |
Angular momentum (I·ω) |
| Counter-rotation |
Two bodies spinning in opposite directions for net L ≈ 0 |
| Sun-pointing / edge-on |
Spin axis pointed at the sun, or perpendicular to the sun line |
| Precession |
Turning the spin axis; costs ≈ 2π·L per year for sun-pointing |
| Despun / non-rotating hub |
A section held stationary relative to inertial space |
| "Zero-g core" |
A de-spun section inside the rotating pressure hull (Twark_Main) |
| Rotating airlock / gangway |
A temporary counter-rotating interface to a visiting vehicle |
| UBM |
Universal Berthing Mechanism (Nexus Aurora, 2 × 2 m passage) |
| CBM / IDSS / NDS / LIDS |
ISS berthing and docking standards |
| ISPR / LSPR |
International Standard Payload Rack / proposed Large Standard Payload Rack |
| ELEO / VLEO / EVLEO |
Equatorial / very low / extreme very low Earth orbit |
| EML-1, L4/L5 |
Earth–Moon Lagrange points |
| SAA |
South Atlantic Anomaly |
| GCR / SPE |
Galactic cosmic rays / solar particle events |
| mSv, Gy |
Dose units: sievert (biological), gray (absorbed) |
| OLTARIS |
NASA's online radiation-transport tool |
| ECLSS |
Environmental control and life-support system |
| ESM |
Equivalent system mass |
| ISRU |
In-situ resource utilization |
| MMOD |
Micrometeoroid and orbital debris |
| CMG |
Control moment gyroscope |
| ISEP |
Electrodynamic propulsion boom concept |
| RCS / OMS |
Reaction control system / orbital manoeuvring system |
| CAM |
ISS Centrifuge Accommodation Module (cancelled) |
| MHU |
JAXA Mouse Habitat Unit (ISS centrifuge) |
| HRP |
NASA Human Research Program |
| CLD / CCSC-2 |
NASA Commercial LEO Destinations / Collaborations for Commercial Space Capabilities-2 |
| SpinCalc |
Theodore Hall's rpm/radius comfort calculator |
| "1% rule" |
Gravity gradient head-to-foot <1% → r ≥ 100 × body height (mikelepage's guess) |
| MVP |
Minimum viable product / minimum viable station |
| Gen 1…5 |
Station generations (Coastal Ron's and Paul451's roadmaps) |
| Class 0–3 |
Twark_Main's taxonomy by number of docking ports |