The 3DSR4M08VS1520 from 3D Plus is a Space Qualified Memory with Storage Capacity 4 Mb, Read Access Time 12 ns, Bit Size 4 Mbit, Radiation Dose 80 krad (Si) (Read Mode), 25 krad (Si) (Write Mode), Mass 2.40 gms. More details for 3DSR4M08VS1520 can be seen below.