To run Elite Dangerous: Horizons in VR players will need:

OS: Windows 7/8/10 64 bit
Processor: Intel Core i7-3770K Quad Core CPU or better / AMD FX 4350 Quad Core CPU or better
Memory: 16 GB RAM
Graphics: Nvidia GTX 980 with 4GB or better
Network: Broadband Internet Connection
Hard Drive: 8 GB available space

For comparison's sake, here are the minimum PC specs for running the title on a standard display:

OS: Windows 7/8/10 64 bit
Processor: Quad Core CPU (4 x 2Ghz)
Memory: 6GB
Graphics: Nvidia GTX 470 / AMD 7240 (DirectX11 functionality required)
Network Broadband Internet Connection
Hard Drive: 8 GB available space