Launch energy
Compare direct translunar injection, Earth-orbit phasing, low-energy transfer, and rideshare constraints.
Past lunar mission
Chang'e 4
Chang'e 4 is a past Moon mission entry covering launch, transfer, lunar operations, and engineering context.
Animated launch, translunar trajectory, lunar operations, and return or descent path.
Mission facts
Launch and expedition data
- Status
- Past
- Agency
- China
- Launch
- 2018
- Vehicle
- Long March 3B
- Destination
- Von Karman crater, far side
- Mission class
- Far-side lander and rover
Trajectory and outcome
Flight sequence
- Trajectory
- Relay-supported far-side descent via Queqiao
- Expedition
- Yutu-2 rover and far-side geology observations
- Outcome
- First soft landing on the lunar far side
Detailed notes
What this mission teaches
- Mission class: Far-side lander and rover.
- Transfer profile: Relay-supported far-side descent via Queqiao.
- Lunar work: Yutu-2 rover and far-side geology observations.
- Result or planning state: First soft landing on the lunar far side.
Technical Review
What to compare against other lunar missions
Navigation
Flybys and orbiters stress tracking and burn accuracy; landers add powered descent, hazard detection, and autonomous terminal guidance.
Surface operations
Rovers, landers, and crewed missions have very different thermal, dust, communications, and power constraints.
Return path
Sample-return and crewed missions add ascent, rendezvous, entry interface, heat shield, and recovery risk.
Mathematical model
Mission trajectory and spacecraft model
Mission visuals combine catalog dates, distance vectors, speed estimates, and schematic spacecraft geometry. They are not CAD-certified vehicle meshes unless a source model is explicitly loaded.
Vector propagation
\[\mathbf{r}(t)=\mathbf{r}_0+\mathbf{v}(t-t_0)\]
For live-distance spacecraft pages, current position is propagated from epoch vector and velocity when high-precision ephemerides are not bundled.
Transfer curve
\[\mathbf{r}_{\mathrm{curve}}(u)=\operatorname{Bezier}\!\left(\mathbf{r}_{\mathrm{launch}},\mathbf{r}_{\mathrm{mid}},\mathbf{r}_{\mathrm{target}}\right)\]
Mission path arcs are schematic transfer curves anchored at meaningful endpoints, not claims of exact reconstructed trajectories.
Dimensional hierarchy
\[T_{\mathrm{world}}=T_{\mathrm{parent}}RS\]
Spacecraft parts are placed with transformation matrices. This proves the generated geometry is internally consistent even when simplified.
Verification standard: the rendered object must be reproducible from stated equations, catalog parameters, or explicit geometric transforms. Visual reference images may inform presentation only; they are not the source of orbital positions, field vectors, accretion-disk gradients, timing, or engineering layout.
Limitations: browser scenes may use bounded scale, compressed distances, simplified two-body dynamics, schematic transfer curves, or educational approximations where full numerical ephemerides, CFD, finite-element models, or general-relativistic ray tracing are outside the page scope. Those simplifications are part of the model contract, not hidden image-based construction.