The key differences with the Sandbox mode KSP has long had are that the new Research and Development facility is open, science activities yield Science points and descriptive "flavor text", and the player can build only with parts from the nodes in the technology tree they've unlocked thus far.
Career progression comes by performing science activities to "research" and unlock currently locked nodes. Every game starts with the Start node unlocked already.
Career mode in future version 0.24[outdated] is expected to have monetary costs for each part used and missions to earn money to fund future missions of the space program. Like the R&D facility, the Mission Control building expected in 0.24 will likely be available only in Career mode. Additionally contracts and reputation.
The first rockets could possibly go anywhere in the vicinity of Kerbin, especially with techniques like explosive decoupling. But most early rockets will barely, if even, exit the atmosphere. However, landing in a new biome means a fresh opportunity for science activities.
It's easy to unlock the first four nodes of the tech tree by performing science activities around Kerbal Space Center, even with only Start node parts. KSC comprises three special surface-only biomes. Regular biomes outside these special biome locations include opportunities for science while the vessel is flying or in space.
There are three science activities that can be done from the start:
Crew and EVA Reports only yield science points the first time performed in a situation and biome. Surface Samples can be repeated, but with diminishing results each time up to six times. So, visiting the same biome multiple times without having new science modules on board isn't very productive.
To accelerate the amount of science returned, it's wise to unlock nodes offering new science modules. With these it is possible to gain even more science to compensate for the fact that technology tree nodes become increasingly expensive.
Later nodes will be difficult at best without visiting other celestial bodies. Kerbin's moons Mun and Minmus are especially primary targets for the middle game as they can be reached quickly and easily. Both also feature biomes, greatly increasing the amount of science that can be done.
It will be important to unlock various batteries and solar power generators for transmitting data until only retrieval to Kerbin will yield Science points. Missions will generally be larger and demand greater mastery of the maneuver node system in Map view.
With good strategy and diligent "mining" to exhaust biome+situation combinations, it's possible to finish the tech tree with just Kerbin and its moons; but it's often faster and more exciting to figure out how to intercept with other planets. Eve and Duna are certainly reachable with conventional rockets. For manned exploration of distant planets, and the high multipliers for doing any Science on them, acquiring the LV-N Atomic Rocket Motor will be very helpful.
Possible future features
Money and Stock
- The Career mode will add limited money, with parts costing the amount shown.
- There will be a limited amount of parts in stock. It has been said that if the parts land safely, they can be reused.
- It is planned that if a part of KSC is damaged, repairing it will cost money.
During a development chat, one of the devs said that things have to be "discovered" with a telescope or probe to find out information about it. For example, if a craft were going to Jool, and looked in Map View, it would look like a giant green sphere unless a probe had already been send there with cameras and scientific instruments. Cameras will be added to the game in a further update.