The opening of Planet's Edge, 9th of May 2045, should be a wonderful moment for humanity: a group of four astronauts is on the verge of launching on a mission to Mars from the joint U.S.-New Soviet base on the moon. The launch is delayed due to a small energy system anomaly on the mission's ship, the UNS Unity. The delay is extended to ten days while the problem is investigated.
At the same time, a computer controlled telescopic system was tracking an unknown object. Continued tracking showed that the object was brighter than a comet should be and was not following its predicted course. These anomalies caused the computer to bring the object to human attention. Photography of the object made it clear the object was actually a ship, and it was given the designation Extraterrestrial Ship (ETS). Friendly messages of peace and welcome were broadcast to the probe. However, it soon became obvious the ETS was headed towards Earth.
Over the next month the probe approached earth. During this time, panic and paranoia spread amongst earth governments. Attempting to moderate the human reaction, all humanities space-effective weapons were put under control of the the United Nations First Approach (UNFA) bureau. UNFA continued to broadcast messages to the ETS with an increasingly cautionary tone, while preparing a team of astronauts to greet the probe on its arrival.
When the probe arrived at Earth, ETS echoed the peace and friendship messages that had been broadcast soon after the probe's discovery. Every sensor available tracked the probe as it circled earth and relayed the information to interested parties around the world. Eventually someone cracked and interceptors launched from Wu Chen station to attack the probe. They did not damage the probe, but got its attention, and it immediately ceased all transmissions.
Three hours later a flash was visible from the ETS followed by a flood of electromagnetic radiation across all bands. When the moment of blindness passed, the Earth had disappeared.
The group remaining on Moonbase established that they were not at risk of drifting off--the mass of the Earth was still exerting a gravitational pull on Luna. The more significant concern was the limited resources and people available without the support of the Earth. Salvage teams dispatched to the ETS were able to retrieve information about its origins and several useful pieces of alien technology including a universal translator and a star drive.
The people at Moonbase decide to assemble a team of four astronauts and a commander to pilot the new UNS Ulysses on a mission to reassemble the 'Centauri Device.' This device was believed to be responsible for the Earth's disappearance, and it was hoped, could be used to reverse the calamity.
The player assumes the role of the Commander of the UNS Ulysses mission. This mostly involves controlling the four crew members from a third person perspective. Occasionally, the astronauts break the fourth wall and address the player directly as "Commander" or "Captain."
There are three areas of gameplay in Planet's Edge: Moonbase, spaceflight and planetary exploration. At Moonbase crew members can be cloned, ships, parts and items can be constructed from resources, gear can be chosen for crew members and ships can be outfitted. Spaceflight must be undertaken to navigate between and within systems, interrupted by occasional combat with hostile ships and starbases. When a planet of interest is discovered your crew of four can beam down and explore the planet.
Moonbase is presented as a static scene with various clickable buildings that take you to a detailed screen with a specific function.
The Shipyard screen allows ships to be outfitted with weapons and engines, or scrapped when they are no longer needed.
At Crew Quarters you are able to clone crew members. This is useful to roll new skils or to replace lost crew members.
New items, ships and ship parts can be constructed at the Warehouse. Inventory levels of raw resources and constructed items are also tallied here.
In the Research Lab the blueprints for the Centauri Device are on display and any collected parts are added to a completed device here.
There are separate buildings to save or load a game and to quit to DOS. (Yep, DOS!)
Finally clicking on the ship on the Launchpad moves the game out in to Spaceflight.
Spaceflight gives the strongest impression of the player's role as the commander of the mission. The display shows the crew on the bridge of the ship, seated at their stations, with a view screen in the centre. Most of the time during spaceflight the view screen displays an overhead 2d view of your ship and any nearby ships, planets or stars. A mini-map on a smaller display in the lower left gives an overview of the current system, or of the nearby area in interstellar space. Crew members turn and address the camera in speech bubbles when carrying out actions.
Once in space the ship's speed and course are controlled directly by setting a speed and steering the ship left or right. All flight happens on a 2d-plane. The ship does not have significant momentum. It travels straight in the direction it is pointing and stops when the engines are turned off. There are different kinds of automatic pilot available in different situations. Previously visited systems can be auto-piloted to. During combat enemy ships can be pursued or the navigation officer can evade.
Clicking on a crew members turns them around and they address the camera as "Commander" or "Captain." Each of the crew members serves as a menu for a particular set of functions. The navigation officer controls auto-pilot, accessing the starmap and orbiting planets. The communication officer can open communications or attack aliens. The science officer can heal the crew, scan planets or beam the crew down to a planet. The engineering officer can manage cargo and report on the ship's status.
If a crew member died while exploring a planet their chair is empty. Their menu can still be accessed by clicking on their station, but one of the other crew members will turn to speak to the camera.