Thursday, December 20, 2012

Turkish Indigenous Reconnaissance and Intelligence Satellite
About

GÖKTÜRK-2 Satellite is originally an Earth Observation Scientific Research and Technology Satellite Development Project which has been funded by The Scientific and Technological Research Council of Turkey (TÜBİTAK) resources. The contract was signed by the Ministry of Defense (MoD), The Scientific and Technological Research Council of Turkey (TÜBİTAK) and TUBİTAK UZAY-TAI consortium on 13 April 2007.  And was also developed by Turkish Aerospace Industries, Inc. (TAI) and The Scientific andTechnological Research Council Space Technologies Research Institute (TÜBİTAK UZAY) Consortium.

Launch and Beyond…

Turkey's second observation satellite GÖKTÜRK-2 was launched successfully from Jiuquan Satellite Launch Center (JSLC) in China.


The first national high-resolution optical observation satellite GÖKTÜRK-2, was launched on December 18, 2012 at 18:13 local time in Turkey with a Long March-2D rocket. It left the launcher at 18:25 local time in Turkey. 

 The first transition signal was received successfully from Tromsø SatelliteStation in Norway at 19:39 local time in Turkey.



Gökturk-2 Technical Specs
Orbit
:Sun Synchronous Orbit
Altitude
: ~ 700 km
Period
:~ 98 minutes
Daily Ground Station Contact
: ~- 40 min (day time and night)
Imaging by Full Coverage of Earth

Real Time Image Transfer

Mass
:< 409 kg.
Image Storage Capacity
:> 15 Gbit
Resolution
: 2,5 m

Usage

The satellite meets the observation, reconnaissance and intelligence needs of the Turkish Armed Forces with high-resolution picture capability.The first pictures from the satellite are expected to be received on December 25-30, 2012.

Wednesday, August 1, 2012

Ion Thrusters and Electric Spacecraft Propulsion

Ion thruster is basically a much better and faster  propulsion system than any other propulsion system already in use.

It sounds like an assertive claim. But you can belive it. Its superior than chemical propulsions in many ways. 


Its an electric propulsion created by accelerating ions. By the method of accelerating ions these thrusters differ as electrostatic and electromagnetic ion thrusters.




Copyright: ESA, Illustration Medialab

Electrostatic ion thrusters use the Coulomb force accelerate ions in the direction of the electric field on the other hand electromagnetic ion thrusters use the Lorentz force. (which is mentioned in almost every article of  this blog)

In my opinion they are better than chemical thrusters in many ways.

-Power and speed of the spacecraft
-The range of a spacecraft.
-Cruising cost
-Pulse preciseness

I will try to explain...
Conventional chemical spacecraft propulsion systems create thrust by thermodynamically expanding heated propellant as through a nozzle. Which can be effective but these systems are limited by the available reaction energies and thermal transfer considerations to exhaust gas velocities of a few thousand metres per second. Electric/electromagnetic propulsion can produce a higher velocity increment for the vehicle. 

A clear comparison table of ESA will show the differences.

Comparison of propulsion technologies



Chemical

Electric

Small monopropellant thruster
Fregat Main Engine (S5.92M)
SMART-1 Hall Effect Thruster(PPS-1350)
Propellant
 Hydrazine
Nitrogen tetroxide / Unsymmetrical dimethyl hydrazine
 Xenon
SpecificImpulse (s)
200
320
1640
Thrust (N)
1
1.96 x 104
6.80 x 10-2
Thrust time (s)
1.66 x 105
877
1.80 x 107
Thrust time (h)
46
0.24
5000
Propellantconsumed (kg)
52
5350
80
TotalImpulse (Ns)
1.1 x 105
1.72 x 107
1.2 x 106
Fregat produces ~ 14 times the total impulse of SMART-1's engine, but uses nearly 70 times more propellant mass to do so. The hydrazine thruster produces less than a tenth as much total impulse while using 65% of the propellant mass.
http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=34201

Another limitation of any chemical propulsion system faces is the storage of the energy or storage of the source of the energy. There are two problems of storage. First it can store a limited supply second they are big and heavy. Bigger and heavier objects are harder to carry to space.
While chemical propulsion systems store their energy in the propellants, the energy required by electric propulsion systems is generated by solar panels so there is no storage to carry to space and there is no limited energy source.

Thats why this could be the only way for mankind to explore outer space.

Applications

Outer space  or in orbit;  Ad Astra VF-200 VASIMR electromagnetic thruster was being considered for placement and testing on the International Space Station.

 "The Variable Specific Impulse Magnetoplasma Rocket, or VASIMR, uses radio waves to create and speed up free-flying, electrically charged particles known as plasma. The concoction is then herded through nozzles made of magnetic fields, not metals like traditional rocket engines."

http://dsc.discovery.com/news/2008/08/07/plasma-rocket.html



LISA Pathfinder
LISA Pathfinder is an ESA spacecraft to be launched in 2013. It will not use ion thrusters as its primary propulsion system, but will use both colloid thrusters and FEEP for very precise altitude control. These kind of precise pulses are possible with electrical propulsion.

Which is a very important part of space flight and navigation.





http://www.esa.int/esaSC/120397_index_1_m.html#subhead7
http://www.rssd.esa.int/index.php?project=LISAPATHFINDER


References