Pakistan to Launch Indigenous Satellite into Space

[punit]

I'm not really knowledgeable about space satellites - can someone tell me the what benefits and uses they have?

are u kidding!

 

[ghauri05]

For that amount of money and time, hardly possible.

If Pak still has no interest in developing SLV....then we are never gonna catch up with other countries...!!!

 

[kṣamā]

If Pak still has no interest in developing SLV....then we are never gonna catch up with other countries...!!!

Thanks for re-hilighting my point. There have been no serious and significant development of any SLV. Why just SLV there is not material intrest in launching any experimental sounding rocket (atleast after the original ones done with NASA). Neither is any test flight of any big heavy missiles with modifications.

 

[ghauri05]

Thanks for re-hilighting my point. There have been no serious and significant development of any SLV. Why just SLV there is not material intrest in launching any experimental sounding rocket (atleast after the original ones done with NASA). Neither is any test flight of any big heavy missiles with modifications.

Our SUPARCO is sleeeping ....and doesn't want to wake up....can't understand why???

 

[touela]

Thanks for re-hilighting my point. There have been no serious and significant development of any SLV. Why just SLV there is not material intrest in launching any experimental sounding rocket (atleast after the original ones done with NASA). Neither is any test flight of any big heavy missiles with modifications.

Why are everybody talking about SLV? There is no need for Pakistan at the moment to make a SLV. That is going to be a massive investment, and frankly I better see Pakistan to just develope sattellites. Then Pay other countries to get them into orbit... focus on SLV is not a prioritet now

 

[Dungeness]

Best wishes for the people of Pakistan. You do have the technology to launch the satellite on your own launch vehicle. The medium range ballistic missile you already have are powerful enough to do the job.

 

[A$HU]

Why are everybody talking about SLV? There is no need for Pakistan at the moment to make a SLV. That is going to be a massive investment, and frankly I better see Pakistan to just develope sattellites. Then Pay other countries to get them into orbit... focus on SLV is not a prioritet now

See the whole point is self reliance.If you can pay for launching costs then you can surely buy some satellites too.Whats the use of even building satellites? But there will come a time possibly in this century only when countries will laying stakes on mineral resources in space and even colonizing it.Does Pakistan wants to be in that list of countries?
And it doesn't mean that Pakistan should allocate a hefty amount of budget for its space program right now. But what it must surely do is atleast layout a vision for the next 20-50 years that what it wants to achieve. Start by building basic technologies like slvs(they are not that costly,trust me),remote sensing satellites.It can also collaborate with like minded countries Turkey or malaysia(China wont give you an slv,they wont lose a customer that easily).
My last point : Its better to start late and progress slowly then to never start at all.

 

[Gen Padmanabhan]

@Gen Padmanabhan
Hi dear,it is quite misleading to think that one can convert a MRBM into a satellite launching vehicle in just 2 months. Pakistan can indeed use shaheen-3 to launch smaller payloads into low earth orbits of <300kms. There is however issue of size of satellite that can be accomodated inside the small nose(payload fairing) of shaheen. Modern launchers have payload fairing diameter in excess of 4meters! Solid fuel although provides a great deal of advantages in missiles- isnt really an ideal choice when it comes to space launchers. It has something to do with itz inherent burning characteristics(or Isp). A cryogenic engine of similar dimensions is way more efficient in space launches. Just to give you a very laymen example- you can have a 17kg payload in a 100kg cryogenic launch system.Whereas in Solid rocket system this payload mass comes down to as low as just 4-5kgs(considering a similar 100kg solid rocket system!).SO essentially,you can launch heavier satellites into orbit with same amount of cryogenic fuel. But mastering cryogenic engine is NOT AT ALL EASY.
WHat many fail to see here is the fact that there needs to be a strong push from pakistani government in this regard. Pakistani space research budget isnt even $70million compared to Indian ISRO budget which is close to $1.5bn(although that too isnt really sufficient for the kind of projects they are undertaking!). Then

Hi,
I know about this, and nobody expecting Pakistan to launch directly a 2000 kg class of Sat. Nobody in world start the SLV program directly from heavier class or launching in GTO.

But atleast a nanosat in LEO, and converting a missile into SLV is as easy as making a car (albeit you should know knowhow of making that missile).

And if you know when Musshy declared SLV program from Shaheen, then you know what I mean. If it not take 2 months to make SLV from IRBM, then neither it take 15 years.

 

[amardeep mishra]

Is the different between solid fuel and liquid fuel come down to energy density? Also The grain size and the motor design contribute to the lifting capacity?

@ksama

Hi kshama, Well i will answer it in very simple terms-
(1) yes liquid fuels generally pack more kJ of energy per unit of weight vis-a-vis their solid counterparts. The exhaust velocities in the case of liquid fuels are also higher leading to higher Isp. However they are generally more difficult to handle or store vis-a-vis solid fuels. Another important aspect is the complex design,liquid engines particularly cryogenic engines are way more complex than the solid rockets. In liquid engines only the combustion chamber and nozzle experience the chamber pressure whereas in solid rocket(due to itz design) the whole of missile casing feels a strong radial pressure.

(2)Grain geometry and size are closely related to the "regression rates" of solid motor. In modern era,a case bonded "star-geometry" is used.

Picture courtesy: Internet
This type of configuration in solid rockets offer nearly flat or stable thrust during most time(popularly known as neutral burning). Thrust is also dependent on the exposed surface area of the propellant. And if by mistake there is a small crack(due to ageing or some other factors) in the shape(geometry) of the grain,then the thrust curve will change drastically,it might even become unstable and explode!. The reason why it might become unstable is because crack provides extra surface area to burn than desired leading to sudden increase in production of gases and hence chamber pressure. And if n>1 then the increase in chamber pressure will grow!
THe equation governing regression rate and chamber pressure is
r=A*P^(n)--------------------------------(for stable operating conditions we ideally need n<1)
Where
r= regression rate
A=pre-exponential factor.
P=chamber pressure
A solid motor normally operates at stable operating point and we find that by equating output flow rate and input flow rate.

 

[kṣamā]

@ksama

Hi kshama, Well i will answer it in very simple terms-
(1) yes liquid fuels generally pack more kJ of energy per unit of weight vis-a-vis their solid counterparts. The exhaust velocities in the case of liquid fuels are also higher leading to higher Isp. However they are generally more difficult to handle or store vis-a-vis solid fuels. Another important aspect is the complex design,liquid engines particularly cryogenic engines are way more complex than the solid rockets. In liquid engines only the combustion chamber and nozzle experience the chamber pressure whereas in solid rocket(due to itz design) the whole of missile casing feels a strong radial pressure.

(2)Grain geometry and size are closely related to the "regression rates" of solid motor. In modern era,a case bonded "star-geometry" is used.
View attachment 297511
Picture courtesy: Internet
This type of configuration in solid rockets offer nearly flat or stable thrust during most time(popularly known as neutral burning). Thrust is also dependent on the exposed surface area of the propellant. And if by mistake there is a small crack(due to ageing or some other factors) in the shape(geometry) of the grain,then the thrust curve will change drastically,it might even become unstable and explode!. The reason why it might become unstable is because crack provides extra surface area to burn than desired leading to sudden increase in production of gases and hence chamber pressure. And if n>1 then the increase in chamber pressure will grow!
THe equation governing regression rate and chamber pressure is
r=A*P^(n)--------------------------------(for stable operating conditions we ideally need n<1)
Where
r= regression rate
A=pre-exponential factor.
P=chamber pressure
A solid motor normally operates at stable operating point and we find that by equating output flow rate and input flow rate.

Thanks for water drowning things for the un initiated. But pls be as geeky as you can while you explain, others can water down things for you. And thanks for refreshing my memory on few things.

Just a random thought, gelatinous fuel mix will not only give you a stable n and will not expose additional surface but the Gel mix can also have a Hybrid liquid fuel which will give higher initial impulse. Also why not change the motor geometry with changing external factor, like higher thrust star geometry till the vehicle breaches atmosphere and a longer burning cylindrical geometry for ext atmospheric stuff. Moreover we could use the same basic elements with different ratios to give different viscocity.

Just a thought.