NASASpaceFlight.com Forum
International Space Flight (ESA, Russia, China and others) => Indian Launchers => Topic started by: Charlie65 on 11/14/2008 08:03 am
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What would be the increase for LEO and GTO payloads for the PSLV if-
1] Agni-3 based solid strapon motors were used instead of the Agni-1 based strapons. (over 1MN compared to 650 kN)
2] These strapons had more segments for a burn time of 80-90s.
3] The Vikas engine (2nd stage) had enough fuel for a 240-300 second burn?
Any idea?
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I go for the 3rd option....ISRO has already prepared a series of PSLV versions...
PSLV-HP version can take more payloads into GTO or LEO... The basic difference between pslv in normal config and the high performance configuration is a upgraded vikas engine(ps-2 stage)...
ISRO has not yet used HP versions...the upcoming launches are of xl configuration(risat, IRNSS...etc)
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Why are some of the strap on's air lit, would it increase the payload capacity if all of them are ground lit? -Thanks
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Why are some of the strap on's air lit, would it increase the payload capacity if all of them are ground lit? -Thanks
Same issue with Delta II, some SRBs are air-lighted so that their extended nozzles provide additional ISP.
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The performance issue with PSLV are not all directly hardware related. For example, if you look at a map of India, you will see that PSLV is constrained in regards to certain launch azimuths. So, sometimes, a dog leg maneuver is required to inject certain payloads, anything that gets PLSV more efficiently beyond the dog leg may provide a non-linear increase in launch performance.
If you are not sure what "non-linear" means in this context, consider this:
For Delta II, each additional SRB provides about 200 kg of additional LEO payload, after the first 3. However, take away the first 3 SRBs, and Delta II doesn't get off the ground, or at least, not very fast, and doesn't make orbit. So, the performance gain from Delta II SRBs is non-linear.
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2] These strapons had more segments for a burn time of 80-90s.
Most solid motors (especially large ones) burn from the inside out, not from one end to the other. More segments would increase the thrust, not the burn time. To increase the burn time (with the same propellant formulation), the outer diameter of the motor would need to be increased.
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2] These strapons had more segments for a burn time of 80-90s.
Most solid motors (especially large ones) burn from the inside out, not from one end to the other. More segments would increase the thrust, not the burn time. To increase the burn time (with the same propellant formulation), the outer diameter of the motor would need to be increased.
Not exactly, which is precisely why Ares-I is going to a 5 segment SRB. There is another factor involved, which is how the propellant grain is bored.
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Urmm , i am just a student and all this feels so scientific . Hopefully when I am done with my aerospace engineering , I will understand all this !