And while Mikoyen has plans for a MiG-31 successor, the MiG-41, the Foxhound will continue flying until at least 2030.
Source: The National Interest.
Moscow currently has about 252 MiG-31s, and plans to make 100 MiG-31BMs and MiG-31BSMs by 2020.
Source: The National Interest.
The Mig-31DZ, a variant released in 1989, was the first MiG-31 able to refuel in midair.
Source: The National Interest.
The Foxhound's main armament is the R-33 long-range missile, which is similar to the F-14s AIM-51 Phoenix missile, and it can lock onto 4 different targets at once.
It can hold 4 of the R-33 long-range missiles, and 2 R-40TD-1 medium range missiles and 4 R-60MK short range missiles. It also has a 9-A-768 23-mm gun.
Source: The National Interest and Globalsecurity.org.
There have been multiple accounts of MiG-31 fighters chasing away SR-71s, the legendary high-altitude US spy plane.
A Russian pilot claimed he was able to lock his missiles onto an SR-71 during one incident, and 6 Foxhounds reportedly cornered a Blackbird in another.
Source: The National Interest and The Aviationist.
The MiG-31 can also reach 65,000 feet in nearly 9 minutes, and even hit altitudes of 67,500 feet.
The second layer of the atmosphere, the stratosphere, starts at 59,000 feet.
Source: Globalsecurity.org.
This is the MiG-31BM, the newest MiG-31 variant, which features a Zaslon-M radar with a range of nearly 200 miles, longer range air-to-air missiles, like the R-33S, and more.
Source: Globalsecurity.org.
It has two Tumanski R-15BD-300 turbojets, which can bring the Foxhound to nearly 34,000 feet in 8 minutes. Below is a shot of the engine's afterburners in action.
Source: Globalsecurity.org.
Unlike the MiG-25, it has a backseat for the Weapons Systems Officer to operate the Zaslon radar.
The Zaslon S-800 Passive Electronically Scanned Array radar was made to track low flying bombers, and originally had a range of 125 miles, which Russia has since upgraded multiple times.
Source: The National Interest.
As an interceptor, the Foxhound was not made for dog fights, but instead for defending Russia's borders from enemy bombers, able to swoop in quickly and hit targets before jetting out.
Source: Globalsecurity.org and The National Interest.
The MiG-31, which NATO calls Foxhound, made it's first flight in 1975 and was the MiG-25s successor.
Source: Globalsecurity.org.