EXPLORATION
W A S D / Q Efree camera: move forward, sideways, up and down in Explore
DRAG / SCROLLlook around / approach an object; two fingers pan on touch screens
SPACE / , .pause time / change its speed; use Events for time jumps
TABmove keyboard focus between controls
FLIGHT
W / ↑main engine: thrust along the nose
S / ↓reverse thrust
A / D, ← / →rotate ship
Q / ERCS lateral translation
SHIFT×4 boost (needed to lift off Earth)
Z / Xthrottle ÷ / ×; no upper limit
T / Yhold prograde / retrograde
AUTOPILOT
SHIFT+Ttravel to the focused body / star
SHIFT+Ccircularize current orbit
SHIFT+Xautopilot off (any manual input takes over)
TIME
1 – 9time warp presets: real time … 1 yr/s
, / .warp ÷2 / ×2; up to 1 Byr/s
SPACEpause
CAMERA & SCALE
Fcamera focus: ship → moon → earth → sun
SHIFT+Fcycle the planets (Mercury … Neptune)
Ccycle Solar / Milky Way / Local Group scale
Ucycle nearby stellar destinations
SHIFT+Ubrowse active stars / search HYG catalog
Jtoggle in-ship cabin view
0 / click labelfocus ship / focus body
hold-drag shipgrab the ship, release with damped velocity
RMB dragpan the free camera (detached from any body)
VISUALIZATION
Ptrajectory prediction on/off
Gspacetime river view on/off
SHIFT+Gconstellation guide lines on/off
Odark-energy expansion on/off
SHIFT+OMilky Way dark-matter halo on/off
BLACK HOLES
Bplacement mode; click the plane to place
ESCexit black-hole placement mode
N / click BHfocus next black hole + telemetry
[ / ]size: r_s 1 m … 5,000,000 km
Vremove last black hole
SYSTEM
Itoggle limited-fuel challenge mode
Mmute sound
Rrestart in low Earth orbit
K / Lquicksave / quickload (browser storage)
SHIFT+Stravel simulations menu
Hthis help
Planet and Moon motion comes from Solar System ephemerides advanced by KDK or velocity-Verlet integration; the sim hands off to analytic osculating Kepler orbits at high warp so planets stay on their tracks. RK4 advances your ship from all Solar System bodies and player-placed holes, plus a capped, priority-ranked subset of nearby stellar sources. A separate RK4 path advances player-placed holes from Solar System bodies, gravitational debris, and other placed holes. Deep-time events such as galaxy passages and stellar eras follow reduced-order equations: simplified models with fixed parameters.
The spacetime river is a velocity-field visualization, an honest picture of the pulls around you. Player-placed holes use the Paczynski-Wiita pseudo-Newtonian approximation. Catalog and special-object black holes, including SGR A*, use the capped active-star Newtonian field. Limited 1PN corrections cover weak-field motion near the Sun. Collisions are classified between simple spheres, with no melting or fragments. Only the Sun evolves as a star, changing its appearance and contact radius. Merger energy loss is bookkeeping; the engine carries no gravitational waveforms.
Galaxy-scale views skip galaxy-wide N-body integration, and the Milky Way and Andromeda dates play one modeled scenario whose real outcome stays uncertain. Shift+O toggles the modeled NFW dark-matter halo; its applied strength is under physics review and currently changes little inside the galactic disk. Drag to orbit the camera; scroll to zoom. You can land on the rocky planets. Aim for the Moon, capture orbit, land, and come home, or dive into something dark.