# Changes from SDX1

SDX2 is a complete remake of the Expanse experience from the ground up. While the theme, feel, and a lot of the core concepts are the same as SDX1, a lot has also changed.

Here’s a list of some of the major differences.

# Mechanics

* **No more fast/slow zones** - you can [go up to 50km/s anywhere](/doc/travel-kMrigtrr3w). Speed is only limited when in potential combat or collision scenarios.
* **A new solar system map** 5-10x larger than SDX1, with every planet, all major moons/asteroids, and a real sun at the centre
* New **mission system** - pick up contracts from stations to earn tech and reputation with NPC factions
* A **reimagined Nation system** (coming soon)
* A wide range of new NPCs and PVE combat encounters

# Building

* Block limits are now handled via a [Ship Core](/doc/ship-cores-7qVjMmN3Tt) system - you can spec your ship into a particular role (Corvette, Frigate, Hauler, etc.) for tailored limits
  * Drive limits are determined by your core, rather than maximum signal
* Revamped tech progression - multiple tiers of tech, multiple tiers of most blocks
  * Different tiers of tech are being gradually unlocked as we roll out features
* Over 500 new and redesigned blocks - weapons, drives, sensors, production, cosmetics, and more.

# Combat

* Overhauled weapon systems
  * Railguns now punch through entire ships
  * Torpedoes have been split into multiple roles
  * Increased specialisations of different PDCs
* Variable maximum speeds based on your class of ship
* A new [Signals and Detection](/doc/ed725ce4-d2bf-4f45-ba6c-a76e4547cf27) system, giving you better control over how you detect other ships through various blocks (Sensors, Lidar, Radar, etc.)


* Thruster and reactor output now degrades as the blocks take damage
* All ships now use Water as propellant - no more exploding hydrogen tanks or fuel can extractors