Astra Missile- Indian Missile development

The Minister of State for Defence recently flagged off the indigenously developed Astra Missiles for supply to the Indian Air Force (IAF) at Bharat Dynamics in Hyderabad.

Astra Missile

• Astra is a beyond-visual-range (BVR) air-to-air missile designed to be mounted on fighter aircraft. 
• It is indigenously developed by the Defence Research and Development Organisation (DRDO) and manufactured by Bharat Dynamics Ltd. (BDL) for the Indian Air Force (IAF).
• The missile is designed to engage and destroy highly manoeuvring supersonic aircraft.
• It is the best in its class of weapon systems in the world in the category of air-to-air missiles.
• The missile is being developed in multiple variants to meet specific requirements.
• The ASTRA Mk-I Weapon System, integrated with SU-30 Mk-I aircraft, is being inducted into the Indian Air Force (IAF).

Features of ASTRA Mk-I:

• • It has a range of 80 to 110 km in a head-on chase and can travel at 4.5 Mach speed (almost hypersonic).
  • The missile also has a locally developed Ku-band active radar guidance system and a 15-kg warhead.
  • It offers the pilot the option to choose between “Lock on Before Launch – LOBL” and “Lock on After Launch – LOAL” and later allows the aircraft to shoot and scoot to safety after firing the missile in the direction of the target.
  • It is based on advanced solid-fuel ducted ramjet (SFDR) engine technology.
  • It is capable of operating under all weather conditions, both day and night, and offers high overall reliability and a very high ”Single Shot Kill Probability – SSKP”. 

Missiles Based on Speed

Missiles are classified based on their speed with respect to that of sound, expressed as Mach.

• Subsonic missile: Missiles that travel slower than sound are known as "subsonic."
  • Examples: U.S. Harpoon anti-ship missile, Indian Prithvi short-range ballistic missile
• Supersonic missile: Missiles that travel faster than the speed of sound (Mach 1) but less than Mach 5 are called "supersonic."
  • Examples: Russian Iskander tactical ballistic missile, Indian BrahMos supersonic cruise missile.
• Hypersonic missile: The term "hypersonic" means that the speed of missiles should be at least five times faster than the speed of sound (over Mach 5).
  • Examples: China's DF-ZF hypersonic glide vehicle, Russia’s Avangard, and Shaurya/Sagarika missiles of India (Max speed - 7.5 Mach), etc.

• Fractional Orbital Bombardment System (FOBS): It is a warhead delivery system that uses a low Earth orbit towards its target destination. Just before reaching the target, it deorbits through a retrograde engine burn.
  • Instead of ICBMs which follow a probable trajectory, FOBS can avoid early warning systems by approaching from the south polar region without the revelation of targets.
  • Example: Russia developed this technology in the 1960s. Recently, China has tested this system too.

Missiles Based on the Launch Mode

Based on Strategic Importance

Strategic missiles encompass missiles that give a strategic edge over an opponent or provide credible deterrence to a country. In India and other powerful countries, these missiles are part of the nuclear triad.

• Intercontinental ballistic missile (ICBM): These missiles are long-range missiles that are capable of delivering nuclear warheads across continents.
  • It is a part of India’s Nuclear Triad.
  • Agni-V is India's first Intercontinental Ballistic Missile(ICBM), with a range of around 5000-8000 km. It brings the entire Asia-Pacific region within its reach.
  • Mission Divyastra successfully tested the Agni-V missile using MIRV (Multiple Independently Targetable Re-entry Vehicle) technology, capable of striking multiple targets hundreds of kilometres apart with a single missile.
• Sub-surface ballistic nuclear (SSBN):  A nuclear-powered submarine carrying and launching ballistic missiles armed with nuclear weapons.
  • K-15 Sagarika (750 km) and K-4 (3500 km, in development) are the Submarine-launched ballistic Missiles (SLBMs), thatcomplete India's nuclear triad by enabling second-strike capability from underwater locations. 
  • K-15 Sagarika has been deployed in Arihant class SSBN.

Based on Tactical Importance

Tactical missiles are employed in the battlefield and frontline combat situations to strike and neutralise enemy assets and capabilities. India boasts an array of tactical missiles.

• Prithvi Missiles: The Prithvi series includes short-range surface-to-surface ballistic missiles.
  • Prithvi-I (150km) and Prithvi-II (350 km) for battlefield roles and hitting strategic targets close to the border.
  • Prithvi-III naval variant (350 km) to boost coastal and seaborne deterrence from warships.
• BrahMos Missile: BrahMos is the fastest supersonic missile of the world.
  • It is a Mach 3 "fire-and-forget" missile, inducted in all three services of the Indian Armed Forces.
  • Its variants include land, ship, submarine, and air-launched missiles.
  • BrahMos II, the hypersonic cruise missile, is currently in the developing phase. 

Types of Missiles Based on Propulsion

Missiles utilise different types of propulsion and guidance systems based on their range, launch platform and targets. Key missile propulsion systems are:

• Solid Propulsion: It uses solid propellants like Hydroxyl-terminated polybutadiene (HTPB) fuel. It is simple, low-cost, and reliable.
  • Example: Prithvi, Brahmos.
• Liquid Propulsion: It employs liquid fuels (Hydrazine - N2H4, Liq. hydrogen, etc.) and oxidisers (Nitrogen tetroxide - N2O4, Liq. oxygen, etc.).
  • It has higher efficiency and throttle ability.
  • Example: Agni series, Akash.
    • Recently, India has successfully tested the Agni-Prime missile with solid propellant, making it lighter than other Agni series missiles.
• Hybrid Propulsion: It uses a combination of solid and liquid propellants. 
  • Example: Used in Brahmos hypersonic cruise missile prototype.
• Cryogenic: It uses liquid oxygen and hydrogen. It has a very high energy density. 
  • Example: Employed in long-range Agni-V ICBM.
• Ramjet/Scramjet: Air-breathing engines are used for hypersonic ballistic and cruise missiles. 
  • Example: Under development (India’s HGV and  Brahmos-II).

Based on Guidance Systems

Guidance systems enable missiles to accurately reach targets. Various guidance technologies are:

• Command Guidance: External commands guide missiles through radio/wire links. 
  • Example: Nag anti-tank missile.
• Inertial Guidance: Onboard computers and motion sensors provide autonomous course correction. 
  • Example: Agni ballistic missiles.
• Terrain Mapping: This compares onboard terrain maps to radar altimeter data for accuracy. 
  • Example: Prithvi missiles.
• Laser Homing: It guides towards a target illuminated by a laser designator. 
  • Example: Helina anti-tank missile, Anti-Tank Guided Missile for MBT Arjun, etc.
• Radar/GPS: This updates position using satellite navigation and matches it to targeting data. Example: Brahmos cruise missile.

Integrated Missile Development Program

• Structured as a phased campaign, IGMDP progressed through technology development, sub-system testing, prototype fabrication, rigorous flight trials, production and eventual induction:
  • 1983-84: Developing infrastructure and training scientific talent.
  • 1984-89: Prithvi and Trishul missile advances.
  • 1989-92: Mastering Nag anti-tank and Akash SAM missiles.
  • 1992- 2008: Mature Agni ballistic missiles proving program success.
• The indigenised outputs enabled India to gatecrash the exclusive club of missile-possessing states - an indicator of technological proficiency conversion into strategic deterrence.
• The IGMDP program also delivered seminal spin-offs like the Long-Range Tracking System, advanced composite materials, high-accuracy ring laser gyros and radomes.
• It laid the foundations for the Integrated Missile Development Center, Defense Technology Center and the Advanced Center for Energetic Materials.
• 2008: After achieving the goal of making India self-reliant (Atma Nirbharta) the DRDO discontinued this program.

Objectives of the IGMDP

The IGMDP set ambitious objectives targeted at developing complete competence in guided missiles natively covering:

• Principal Technologies: The Integrated Guided Missile Development Programme established research facilities and hands-on mastery over dozens of technologies needed - propellants, aerodynamics, navigation, control systems etc.
• Production Infrastructure: This Program set up dedicated assembly lines and facilities so developed missiles can be manufactured in numbers efficiently.
• Deployment Capabilities: This Program enables the transition of successfully developed missile systems into the armed services through extensive field trials validation and induction into units.