Build 25309432

Apogee — Playtest Build 12 - 14 September

This one is about the things a vehicle does to the people in it, and the things a planet does to the vehicle.

Heating happens to a surface now, not to a spacecraft. A heat shield protects what is behind it and nothing else, every part has its own temperature limit, and a part that passes it comes off rather than ending the flight. A capsule flown home backwards burns through with its shield untouched in its own wake, which is what it always should have done.

And a crew can die of more than running out of air: of g-force, of an EVA that went on too long, of being abandoned. None of those had any consequence before. They are also the reason the rest of this update is about giving you the information to avoid them.

Before you fly: things that will be different about craft you already have

• Strap-on parts sit centered on their parent, not flush with its bottom. That is the default for the new position slider (see below), and existing craft load with it — so a booster shorter than its core will move up. Slide it back if you want it where it was.
• Engines are the diameter their catalog entry says. They used to be resized to match the tank above them. A saved engine that names a catalog part gets its real size back on load, and the assembly building reports that as a repair.
• Vehicles turn with the hardware they carry. Every vehicle used to share one generous turning rate. Now it comes from gimbals, reaction wheels and RCS, and a typical launcher turns at 1–5% of the old figure. That is plenty for a gravity turn, but a stack with nothing to steer it is flagged in red.
• Re-entries that used to work may not. Antennas and solar panels now fail at 550–750 K, and a shield narrower than the vehicle only protects what is directly behind it. Retract, jettison or rethink before you come home.
• A lander on the Moon can no longer be "recovered". It can be written off (see Crew).

Re-entry

• A heat shield protects what is behind it. There used to be one skin temperature, one pool of ablator and one heat limit for the whole vehicle, so a shield bolted to the tail protected the nose. Now each part is exposed in proportion to how much of its face meets the airflow, with a wake that widens behind whatever is upstream. Measured on the same capsule flown both ways: shield first, the capsule sits at 900 K and uses 64 kg of ablator. Shield trailing, the capsule burns through at 1,402 K with all 250 kg of shield untouched.
• Parts fail one at a time. Each part has its own heat limit. Passing it costs you that part, plus anything held on only through it, and the flight log says which part and at what temperature. The mission ends only if the part that flies the vehicle is the one that went. A mast that fails at 602 K ahead of a shielded capsule comes off as debris, and the capsule flies on.
• A shield counts whichever tab you built it on. The vehicle's ablator was only totaled while the Engineering tab was on screen. Fit a shield on the Staging tab, press FLY, and it launched with whatever the total had been last time you looked, which could be zero.
• The entry corridor planner and the flight agree exactly. Heated area is the vehicle's frontal disc now, not the sum of every aero surface including fins. They used to disagree by 7.4%.
• Parachutes weigh something. A fixed charge for the pack and mortar plus a rate for the fabric, calibrated on Apollo's: this game's main is 34 kg and its drogue 10. Touchdown speeds quoted in the assembly building include it.
• Parachutes are drawn. The canopy opens as it inflates in the simulation: lines pay out, then the fabric fills. It streams into the airflow rather than along the vehicle, and it is drawn at the size its drag area implies. The 210 m² main is 18 m across.

Crew

• G-force kills. Above 20 g the crew is lost instantly. Between 12 and 20 g they can take 30 seconds, and dropping below 4 g resets that allowance. Between 4 and 12 g the clock neither runs nor rewinds. It is measured on the load the airframe transmits, so free fall is weightless however fast you are going. A countdown bar appears as soon as the clock starts running.
• An EVA costs air. Pressing EVA used to kill the crew member on the first tick and end the mission. The suit carries its own supply now, the pack runs down in mission time (so it speeds up with warp), and it is not refilled by climbing back in. If it runs out, that astronaut is lost by name and goes to the memorial, and everyone else comes home.
• An astronaut outside looks like a person. The EVA used to draw as a barrel, alone, with the ship not drawn at all. Now there is a suited figure, the ship beside them at the real distance, and a slack tether line between the two when one is fitted.
• EVA is flown in Earth orbit first. The contract ladder has a new Extravehicular Activity step between the uncrewed and crewed lunar landings, and it gates the crewed one. EVA Operations no longer requires a docking: a spacewalk needs a hatch and a suit, not a second vehicle.
• The EVA section is hidden until you have researched it, and so is the auto-abort checkbox. Both were four lines of disabled controls on the panel you read while flying.
• A flight cannot end with somebody outside. Recovery is refused, and the panel says why.
• A seat is not a person. The flight counted seats, not occupants, so an empty three-seat capsule flown by a probe core breathed for three and reported three aboard. It counts the crew you actually assigned now, and a crew-rated vehicle can fly empty as long as something aboard can fly it.
• Crew left on a station are not available for the next launch. They show in the assembly building as "aboard <vessel>", and taking control of that vessel brings them back.
• Abandoning a crewed vessel kills the crew. Previously they simply stopped existing: off the roster because they were aboard, and never added to the memorial. The confirmation dialog now lists them by name.
• Recovery means coming home. A vehicle landed intact on the Moon was being counted as recovered, which paid out return-trip science and credited the crew with coming home. You can still end that flight with Write it off: the mission is booked and the vehicle stays where it is.
• A rocket with nothing aboard cannot roll out. You need a cabin or a probe core. The launch button was available for a tank with an engine on it.

Coming down

• The de-orbit panel says where you will land. Latitude, longitude, time to impact and arrival speed, measured against the actual terrain rather than the reference sphere.
• You can choose a landing site in the de-orbit panel and change it in Landing Guidance. The bodies here do not rotate, so a site off your ground track can only be reached with a plane change. The panel shows how far off-track the site is and what closing that gap costs, and leaves the decision to you. On a 100 km lunar orbit, 10° off-track is 303 km and 285 m/s.
• Solve the burn for this site, then load it onto the node. The solver picks when to burn at your chosen periapsis, so the arrival stays steep enough to fly. It does not quietly spend delta-v closing a cross-range gap.
• An airless de-orbit gets a suggestion too. Without an atmosphere, the limit is the lowest periapsis your engine can still brake from. The panel computes that for your vehicle and suggests a periapsis above it. On a 4 t lander with 45 kN the limit is 12.7 km and the suggestion 17.9 km, about where a real lunar descent starts.
• The landing burn holds a throttle setting. The throttle flickered between 0 and 1 many times a second. Now the burn commits once it lights and flies the throttle that stops you in the altitude you have left. On the test descent that took 344 on/off switches to none and saved 17 kg of propellant.
• Landing guidance sees terrain ahead. It plans against the highest ground between you and the touchdown point, not just what is directly below. A 2,000 m ridge ahead starts the burn 2 km earlier. The radar altimeter readout still shows what is below you.
• Craft stand on their feet. Landed vehicles were resting on their center of mass, buried to the waist.
• Guidance resets to Ascent after a landing. It kept describing a landing that was over.
• Autoland can be armed before the descent begins. The checkbox used to appear only once the landing numbers did. Armed early, it reads "waiting for the descent to begin".
• The site readout holds still. The slope and "path clear" readings were remeasured every frame at a spot a few meters further on, so they flickered. They now change only when the predicted site moves by 200 m. The slope is printed in one place, with the warning after it, and the datum sits on the line under the altimeter.

Planning and waiting

• Launch windows have a width, and the launch can wait for one. Tick Auto Launch in Window and the clock warps to the window and releases the clamps inside it. Inside a window, the panel counts down to when it closes.
• The pad has a clock. The mission clock still starts at liftoff, but the world moves on while you wait, so the target satellite or moon moves too. On the clamps, or at rest on any surface, warp is limited only by what your machine can keep up with, up to 50,000x (replacing the 10,000x cap from the last update).
• A moon target gives you a deadline. There is always a launch plane that reaches it, but the heading changes over time. The panel says how long the heading on screen stays within a degree of correct.
• Change Orbit. Circularize, De-orbit and Change Ap/Pe are one tab, with a checkbox for each special case. The planner has five tabs instead of seven, so none are hidden behind scroll arrows.
• A rendezvous loads every burn. The planner used to load only the first burn and show the second as text. Now both go into the burn queue. After flying both on the test case, the chaser ended 0.21 km from the target at 0.00 m/s.
• The burn queue is in Guidance. Any queued burn can be loaded onto the node without removing it from the queue. The two "clear" buttons are now Clear the node and Discard every plan. Clear the node is red and asks first, quoting the burn it will clear.
• The Armed checkbox stays when burns are queued behind an empty node. Flying a hand-built burn no longer strands the queue behind it.
• Jumps go as far as they can. On an orbit that dips into air or down to the ground, jump used to disappear entirely. Now there is a row named for what stops it ("the air" or "the ground"), and targets past that point are not offered.
• Warp buttons work after a jump. The top bar arrows used to be overridden by the automatic warp on the next frame. The duplicate warp controls in the Controls panel are gone; the top bar has the working set.
• Click another craft in map view to draw its orbit and show its numbers in Orbit Info next to yours. Click empty space to clear it.
• Short ranges read in meters. Closest approach switches below 1 km, and "range now" below 10 km.
• The orbital map panel is gone. Everything on it was duplicated elsewhere, except the preview of what a planned burn does, which now sits under the sliders in the planner's Manual tab.

The assembly building

• Hover a part to see what it is: thrust at sea level and in vacuum, Isp, throttle range, mass, capacity, seats, power. The numbers are derived the same way the vehicle derives them, and locked parts show them too.
• Strap-ons have a position slider along their parent, defaulting to centered, and the whole symmetry set moves together. A radial decoupler cannot slide past the end of the part it is clamped to.
• Engine clusters must fit. Engines keep their own size, so the building refuses a cluster that won't fit inside the part above and tells you the widest engine that would.
• Adapters only appear in the stack, and never under an engine. Craft were being charged for tapers at radial mounts and under engines that nothing drew. Across the shipped craft that was 18.2 tonnes of phantom mass.
• Decouplers only go where they can work. A radial decoupler cannot be placed in the stack, and a stack separator cannot be mounted on the side. Either would build, fly and then drop nothing.
• Connections are read-only. Detach and the joint-type selector are gone. Both could leave a part hanging off the wrong thing with nothing in the building to fix it. Structure comes from how a part was placed, and separation comes from separator parts.
• Test firing shows what it buys. For example: "fails to light 2.00% → 1.52% after one more". The panel also tells you when a firing won't help: a vehicle's risk is set by its least-tested engine.
• A redundant igniter applies to every booster in a ring, not just the selected one.
• Parts mounted on a booster ring show where their count comes from, with a button to select that part, instead of a slider reading 1.
• The schematic shows stage numbers next to each part while the Staging tab is open.
• Solid boosters are named by thrust (Solid Booster (2334kN) and so on) and open at a round length. The two parts both called "Launch Escape Tower" can be told apart now.
• A solid booster's delta-v counts in the stage that lights it. Its stage could read 0 m/s if the separation was wired wrong.
• Simulate loads tracks joints through staging. After a separation, loads could be filed against the wrong joint.
• Size-limit messages can't show the limit as the measurement. "35.0 is over limit 35.0" no longer happens.
• Life support is shown once, under Endurance, at the rate the flight actually uses (7.2 kg per crew per day).
• Less text. Several captions that repeated what a control or title already said are gone. "Insert radial decoupler" no longer appears on a decoupler, and the part hover card no longer covers its own labels.

Hardware

• Gimbals, reaction wheels and RCS do something. Boosters gimbal 6°, upper stages 4°, verniers 25°, and pre-TVC engines 2°, which is what the Thrust Vector Control node is for. A crewed capsule carries about 5 kN·m of attitude control, and the large wheel 6 kN·m. The assembly building shows turning rate next to TWR.
• The fuel cell makes power in shadow, at night on the Moon, anywhere: 1,400 W for 89 hours. It runs out, and no cell in the catalog lasts a lunar night. Both the flight and assembly building power readouts show it separately.
• The crew transfer tunnel and orbital module add cabin volume, which slows the CO₂ rise, and the orbital module carries 120 kg of stores. The tunnel drops from 320 kg to 180.

The research tree

• The tree costs 3,085 science, down from 4,345. Thirty-one nodes came down and none went up. A program that flies the contracts and lands on the Moon once can afford all of it with room to spare. You should not have to repeat flights to finish your research. The deep nodes still cost enough to feel earned.
• Halo Orbits is merged into Relay Networks, which now sells both relay dishes.
• Rendezvous Operations is gone. It had no parts and unlocked nothing that was locked. Docking now follows Precision Guidance.

Fixes

• Waiting on the pad ran the world at double speed and left the flight behind. Every second on the clamps was counted twice by the calendar and not at all by the flight. After an hour's wait, the Moon on screen, the Moon the launch was planned against and the Moon the rocket flew toward were in three different places. All three now use the same clock.
• Reverting to launch rewinds the program's clock. It kept the days you had flown, so crew aged and contracts expired for a flight that never happened, and the Moon was drawn somewhere other than where the flight thought it was.
• Contracts that read "reach an altitude of 0 km". An unrecognized objective used to turn into that one, which was already met on the pad and could pay out. It now shows as an objective this version cannot read, which is never met, and you can abandon that contract.
• The auto-stager keeps your last engine. It used to drop a spent stage even when nothing behind it could fly. It now holds and says why. Manual staging is unchanged.
• The two "Load into the node" buttons in the landing site panel loaded different burns but shared an internal id, so pressing one could trigger the other. The site button is renamed.
• A satellite around the Moon, selected from Earth, is described against the Moon, with no range quoted between two vessels measured from different bodies.

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 876 checks on each.