The 79LV0408 from Data Device Corporation is a Space Qualified Memory with Storage Capacity 4 Mb, Read Access Time 200 to 250 ns, Write Access Time 15 ms, Radiation Dose 10 krad, 25 krad, 40 krad, 60 krad, Mass 10 gms, 23 gms. More details for 79LV0408 can be seen below.