Maverick Missile limitations

[Zimmerdylan]

I was chatting with an A10 pilot about the Maverick missile and it's ability to seek at longer distances using the targeting pod.

As we talked, he began to talk about why the Maverick on it's own is limited to the relatively short distance that it is. What he told me confused me and really surprised me. He told me that the maverick itself is capable of finding and launching on a target 20 ft. or larger from over 10 miles. The problem is that it uses a thermal battery that supplies power for a limited time, and after it burns out, the missile loses it's ability to stay on course effectively. Although this made sense, it was something that I had never thought about before. SO I started to do some investigating on it. It turns out that the Maverick as it sits on the rail of an A10 or whatever it is mounted to, is capable of seeking at great distances but the aircraft itself limits that ability. This is because of the thermal battery. Example: This pilot told me that the A10's computer determines the distance that the A10 can lock at and at what size object. When the screen in the cockpit signals a lock by the pulsing cross hairs. The object that it locked on to must fill 1/2 the distance between the gap of where the two (vertical, and horizontal) lines come together. And this is to ensure that the battery will live long enough to facilitate the missile. When I researched thermal batteries in missiles, I understood why:

 

1. 
   
2. 6. APPLICATION 1: THERMAL BATTERY IN MISSILES
   
3. 7. POSITION OF THE BATTERY IN MISSILE The components that a missile has: •Guidance section •Warhead •Midbody section •Propulsion section •Control actuator section
   
4. 8. • The control actuator section maneuvers the missile during flight and provides internal electrical power. The control actuator section consists of four control fins, four thrust vector control vanes, and a thermal battery. • The thermal battery provides internal electrical power for the missile during flight. It is sealed in the body of the missile.
   
5. 9. HOW IT WORKS IN MISSILE Thermal batteries in missiles provide several output voltages from one battery. They are compatible with pulse regime as well as steady load demands. They easily replace several power-sources with a considerable gain in volume, weight and reliability, becoming the sole source of onboard power to electronics and actuators.
   
6. 10. • These batteries are totally inert prior to activation. They are therefore completely maintenance-free over a very long storage-life, and are the only power sources able to operate reliably in very harsh environments. • This includes extremely low and high temperatures (they have a range of more than 100°C), extremes of pressure, EMI, acceleration, etc
   
7. 11. WHY THERMAL BATTERY ? The thermal battery is the ideal solution for artillery shells and smart munitions because of its intrinsic qualities, especially robustness with regards to harsh environments and storage conditions. Moreover, a built-in sticker mechanism can allow self activation under launch-acceleration effects. Recent innovations have allowed the repackaging of the thermal battery to provide all the advantages within a miniaturised volume: by combining innovative manufacturing process and new electro chemistries, a power of 2W is now available in a volume of around 1.5cm³.
   

But this left another question in my head. "Then why is the range longer using the TGP if the Maverick itself is able to achieve that kind of range?"

My only conclusion is that when the Maverick is turned on, on the rail to seek, it may start using the battery immediately. And the power that is consumes on the rail is set so that it only consumes a specified amount. But when the TGP is used, the maverick sits dormant, not using the thermal battery until it is launched. This makes sense to me because this pilot told me that at the instant a Maverick is launched, it shuts down the optical power and it resets back on a second later.

Anyone know anything about this? I may have completely misunderstood this guy but I don't think so.

 

http://www.eaglepicher.com/publications/158-book-chapters/371-thermal-batteries

Abstract for "Thermal Batteries"

Thermal batteries are primary reserve batteries that employ inorganic salt electrolytes. These electrolytes are relatively non-conductive solids at ambient temperatures. Integral to the thermal battery are pyrotechnic materials scaled to supply sufficient thermal energy to melt the electrolyte. The molten electrolyte is highly conductive, and high currents may then be drawn from the cell.

 

The activated life of a thermal battery depends on several factors involving cell chemistry and construction. Once activated, and as long as the electrolyte remains molten, thermal batteries may supply current, discharging the active materials to the point of functional exhaustion. On the other hand, even with excess active materials present, the batteries will eventually cease functioning due to loss of internal heat and subsequent re-solidification of the electrolyte. Hence two of the primary factors behind thermal battery active life are: 1) Compositions and massed of the active cell stack materials (i.e. anodes and cathodes), and 2) other construction details, including the overall battery shape and types and amounts of thermal insulation. Depending on the battery design, which is ultimately determined by the specific requirements of the application, the activated thermal battery may supply electric power for only a few seconds, or may function for over an hour.

Initiation of a thermal battery is normally provided by an energy impulse from an external source to a built-in initiator. The initiator, typically an electric match, an electro-explosive device (squib), or a percussion primer, ignites the cell stack pyrotechnics. Rise time, the time interval between the initiation impulse and that time at which the battery can sustain a current at voltage, varies as a function of battery size, design, and chemistry. Rise times of several hundred milliseconds are not uncommon for large units. Small batteries have been designed to reliably achieve operating conditions withing 10 to 20 milliseconds.

The shelf life of an unactivated thermal battery is typically 10-25 years, depending upon design. Once activated and discharged, though, they are not reusable or rechargeable.

Current developments in extending the activated life capabilities of thermal batteries have widened their suitability and application potential in new military as well as industrial/civilian systems.

Edited December 13, 2015 by Zimmerdylan

[Mike5560]

But this left another question in my head. "Then why is the range longer using the TGP if the Maverick itself is able to achieve that kind of range?"

 

I'm not sure what you mean by your question. The way I understand it, (and this may be completely untrue) is that the AGM-65 is powered by the aircraft when on the rail; the one second delay you mentioned after launch has to do with the internal transition from offboard power to the thermal battery. The battery just doesn't last very long in-flight, and the only reason the aircraft prevents you from launching at too great of a range is to prevent the pilot from wasting a missile. Once the battery runs out, it's running on a memory of the target through inertial guidance. Similar to a HARM missile in flight when the target radar turns off.

[Zane33]

So... why not add another battery? Or a wire like with TOW missiles? Seems like a design flaw to me.

[mattebubben]

A reason for not having a wire is probably because it would limit the options for a pilot.

 

First it would probably limit the range but it would also most likley make the missile less of a Fire and Forget weapon since you would be limited in youre manuvers after launch to keep the wire intact etc.

 

And also it would probably be a very much different thing to have an electrical wire to transfer power to the missile then it would be to have an extremley thin wire that tranfers the command signals for wire guided missiles.

 

And why not just add another Battery?

 

Space and Weight.

 

There is not alot of free space in a missile so there would be no place to put the second battery only way would be to make the missile bigger.

 

And that would increase weight and would probably require a larger engine to keep the same range etc so that would not be a brilliant solution either since it would give the weapon other limitations.

 

You have to remember that the AGM-65 is an Old weapon.

 

Sure it has been upgraded over the time with new variants but its still an old design.

 

And most weapon systems have downsides and limitations and this limitation has a minor impact on the weapons effectiveness as long as its employed within the correct launch parameters.

[GGTharos]

The AGM-65 has a range of 27nm if launched high and fast.

 

The main limitation is 'blob size'. To use this range you need a data-link. The target needs to fill a certain number of pixels, not for battery purposes, but for tracking purposes.

 

It's highly unlikely IMHO that you could lock into onto a single pixel target, and DCS gives a bit of a poor impression of what the 65D display looks like: It's analog, but everything in DCS is digital, so it's extra crisp/sharp, there's no bloom effect etc.