Apogee — Update, 4 September
This is a big one. Three systems that were quietly inert — electrical power, aerodynamic surfaces, and the facility upgrades your program pays for — now do the job their descriptions always claimed. The planner learned to offer you a choice instead of one answer. And Earth and the Moon are the real ones, measured, all the way down to the altimeter.
Electrical power is a real system
Batteries, solar panels and the fuel cell used to be mass with a name on it. They cost you kilograms and bought nothing at all.
- Storage, generation and load are simulated. Watt-hours of battery, watts of panel output in full sunlight, watts of standing load — summed from the parts still attached, so jettisoning a stage takes its batteries and its arrays with it.
- Night is real. A panel makes its full rating in the sun and nothing in the planet's shadow, which is about a third of every low orbit. The battery is what carries you through it.
- Things actually draw power now. Command pods, antennas, reaction wheels, life support and every science instrument have an authored draw. A crewed vehicle runs several hundred watts across a dozen parts.
- A flat battery stops the guidance computer. The vehicle keeps doing whatever it was last told, and nothing new gets through until there is charge again.
- New Electrical tab in the VAB's Analysis panel. Storage, production and consumption as totals, then two tables: what stores and generates, and what spends — sorted heaviest first, with each part's share of the total. If you are 119 W short in full sunlight, this is the screen that says which part is doing it.
- New Electrical panel in flight, with the store, generation, whether you are in sunlight, and the running net.
- Endurance in shadow is called out at design time, and warned about when it will not survive a single low-orbit night.
Fins finally fly
Aerodynamic lift, drag and torque have been modeled since the second milestone. The problem was that a fin bolted on in the assembly building never became a surface the flight could see, so it was pure mass.
- Fins are aerodynamic surfaces. Planform area, lift-curve slope and edge-on drag, all authored per part, all read by the flight.
- Rockets are naturally unstable, and a fin is what fixes it. The hull's own drag now acts at its center of pressure, which on a tall stack sits ahead of the center of mass — so an unfinned rocket wants to tumble, and fins move the balance back. The VAB reports the stability margin.
- Aerodynamic pitch damping. Each station on a rotating vehicle meets a different airflow, which is what stops a stable craft ringing instead of settling.
- A lift-direction bug dating to M2 is fixed. Lift now acts along the crossflow rather than along an ambiguous perpendicular, so surfaces push the way they should.
Engines and the parts catalog
- Throttle floors are real. An engine with a 60% floor cannot hover a light lander — it climbs at idle. The commanded 0–100% now maps into each engine's usable band, and zero always means shutdown. Landing guidance pulses below the floor rather than pretending it can hold 20%.
- A tab per propellant. Thirty liquid engines in one scrolling list became Kerolox, Hydrolox, Methalox and Hypergolic tabs, kept together in the category list.
- Tanks take any propellant you own an engine for, and the separate hydrolox, methalox and hypergolic tank parts are gone — a tank is a tank of that diameter with something in it.
- Monopropellant tanks moved to RCS, and the "Tanks" category is now "Fuel Tanks".
- Solid boosters are worth fitting.
- Separation motors retired. They cost mass and money for something the simulation never modeled. Craft carrying one still load, and say what was removed.
- Radial symmetry can be changed after the fact. Deciding a pair of boosters should have been four no longer means deleting them and rebuilding everything hung off them.
- Solar arrays are drawn as flat wings instead of cylinders, because that is what one is.
Mission planning
- Rendezvous is a phasing orbit, not a three-year wait. Waiting for a natural window between two near-co-orbital craft is genuinely unbounded, which is why the old solver flickered between answers thousands of hours apart. It now plans a phasing orbit — raise or lower, catch up, come back — and offers a list of options with their waits and costs, the way the transfer planner does.
- The way home is a trade too. Return trips get the same list of options rather than one answer.
- Multiple transfer options everywhere. The transfer planner used to show alternatives only for Earth→Moon; it now solves them for any transfer, and can be asked to go direct or to leave soon.
- A long burn is not an impulse, and the planner says so — a burn that takes several minutes does not deliver its delta-v at a point.
- Free return is a checkbox on the transfer, not a rival button beside it. Two solved plans with two Load buttons is how you fly a burn you never planned.
- A plan means the moment it named. Warping four days after solving used to push the node four days late, carrying a vector computed for geometry the vehicle had left. Plans now carry the epoch they were solved at.
- The way home can be trimmed. A lunar return arriving at the wrong perigee now has a mid-course correction to fix it.
- An escape can still be captured. A hyperbola has no apoapsis but a perfectly good periapsis, and a craft falling toward one is exactly where a capture panel should have something to say.
- Orbit Info says where the arc ends up when it crosses a sphere of influence, instead of describing a lunar trajectory as an enormous Earth ellipse.
- The map shows the orbit; the planner plans the burn. The same controls used to live in two windows at once, editing one plan.
Earth is Earth, and the Moon is the Moon
- Real Earth terrain, from ETOPO5. The procedural planet was a perfectly good world and it was not ours.
- Real lunar terrain, from LOLA — the Lunar Orbiter Laser Altimeter record. If you know where Tranquillitatis is, you can find it.
- The screen draws the ground the altimeter reads. The baked elevation went into what the flight measures before it went into what it renders, so the number and the picture briefly described two different planets. They agree now.
- Finer ground up close, with options for how far to push it.
- Orbit lines stay curved when you zoom in instead of going visibly polygonal.
Your program
- The buildings decide what you can fly. The launch pad's mass cap and the assembly building's part, height and width caps were sold on the upgrade screen and read by nothing. They are enforced now.
- The pad and the assembly building grow to the size of a real rocket. The old ladder topped out at 140 tonnes; a Saturn V is 2,890 on the pad, so a fully upgraded pad used to refuse nearly every vehicle you build after Earth orbit.
- The R&D complex is worth its upgrade screen. Science rate and reanalysis had sat on the ladder since M3, priced in the hundreds of thousands, read by nobody.
- The astronaut complex trains a tier. Every program could previously hire all three specializations on day one at the cheapest building.
- Facility rungs repriced against what a program actually collects, measured off the real contract generator.
- Commercial customers ask for a payload the pad can lift. The reward mass was drawn as a large fraction of your mass limit, which has the physics backwards — a launch vehicle delivers a few percent of what it weighs.
- A contract the catalog cannot satisfy is withdrawn on load, rather than sitting on the board forever.
- Lunar orbit contracts require a lunar orbit. The old objective was satisfied by the Earth parking orbit every lunar mission starts in, plus a graze of the Moon's sphere of influence — a free return ticked both and never captured at all.
- A crew lost to life support is lost to the program. The simulation had latched it and printed it on the flight screen the whole time; the debrief decided survival by whether the capsule was recovered, so it logged them a mission and paid them experience.
Tracking station
- Fleet rows say which world they orbit. Every row subtracted Earth's radius from everything, so a 100 km lunar orbit read as 4,500 km underground.
- A fleet vessel remembers which world it is going round. Craft loaded from the fleet used to come back in Earth orbit whatever they had been orbiting — for a lunar one, an immediate failure — and satellites around anything but Earth did not appear in the solar view.
- Rows say when the link next changes.
Flight controls
- Hold can be aimed. The new Hold Config panel, beside Controls, takes a pitch, a heading and a roll, and SAS in Hold flies to them. Out of Hold the fields follow the nose, so the panel reads as a digital navball — and selecting Hold takes whatever the vehicle was doing at that moment as the target, which is what Hold has always meant.
- Roll can be held. It could not be commanded at all before: a direction says nothing about rotation about itself.
- Pitch carries on over the top. The slider runs the full ±180°, so tipping the nose back past vertical no longer means spinning the heading around 180° as well.
- Keyboard controls work with a panel focused. Clicking any slider used to take the throttle and staging with it, and the only way back was to click the sky. Only an active text field captures keys now.
- Map view gets the cockpit keys. Circularizing while watching the map no longer means a round trip to the cockpit and back.
- RCS trim for burns, and floor-aware landing guidance that pulses.
- 5,000x fills the gap in the warp ladder between 1,000 and 10,000.
- A burn's numbers stop moving once the engine is lit.
- The HUD gets out of the middle of the screen.
- "Stage Info" is now "Thrust" — it named where the numbers came from rather than what they tell you.
Fixes
- Saved craft lost their batteries, solar panels and fins. The electrical and aerodynamic properties were added to the parts, the catalog, the editor and the simulation — and not to the craft file. A battery worked in the VAB until you pressed save. Every craft already on disk is repaired on load, and the check that found it now sweeps the whole catalog: 139 parts, 77 authored properties, every one required to survive a stale file and a re-save. Writing that check turned up a heat shield's ablator in the same state.
- Instrument bays were free power. Every instrument has had an authored draw since they went in and nothing summed them, because an instrument is a fitting inside a part rather than a part.
- No power readout before launch. The held-on-pad path returned before the electrical balance was ever published, so a vehicle sitting on the clamps reported no battery and no panels however many were bolted on.
- Engines came off disk burning kerolox. The propellant was only written for parts carrying fuel, and an engine carries none — so a hydrolox stage, saved and reloaded, drew on the kerolox tanks beside it and refused its own.
- The rendezvous readout in the cockpit stopped re-solving every frame.
- The cheapest option shown is the cheapest one — the comparison was running across families that are not comparable.
- A delivery is one payload, and it stays where it was delivered.
- A flight test names the part, and asks for one you can actually fit.
- Life support tells the truth on the pad.
- The tutorial stopped telling new players things that were not true.
As always: the core simulation is deterministic and dependency-free, and every build is verified bit-identical across two compilers before it ships. This update runs 752 checks on each.