ISRO - The Latest updates

[Robinhood Pandey]

ISRO going to Launch its PSLV-C24 rocket with IRNSS satellite, on 4th April, at 17:14 hrs.

is it the second satellite of the 7 satellite constellation of IRNSS ?

 

[ptltejas]

is it the second satellite of the 7 satellite constellation of IRNSS ?

Seven satellites with the prefix "IRNSS-1" will constitute the space segment of the IRNSS.
IRNSS-1A
, the first of the seven satellites of the IRNSS constellation, was built at ISRO Satellite Centre, Bangalore, costing INR
125 crore
(US$20 million).
It has a lift-off mass of 1380 kg, and carries a navigation payload and a C-band
ranging transponder, which operates in L5 band
(1176.45 MHz) and S band
(2492.028 MHz).
An optimised I-1K bus structure with a power handling capability of around 1600 watts is used and is designed for a ten-year mission.
The satellite was launched on-board PSLV-C22
on 1 July 2013 from the Satish Dhawan Space Centre
at Sriharikota, while the full constellation is planned to be placed in orbit by 2015.

IRNSS-1B will be launched in March 2014 on-board PSLV C24.

wikipedia

 

[ptltejas]

 

[ptltejas]

 

[Aegis DDG]

Well If U know about DOR and also about Quasars, hats off sir;
I get search one post in Bharat Rakshak forum which is as under, may it will be useful, as in it its refer that any Quasar near 10 degree may be used for it.

Its as under

poster (prasannasimha) Bharat Rakshak • View topic - Mangalyaan : ISRO's Mars Orbiter Mission

From the German Wikipedia site
Delta-DOR method
The Delta-DOR method (English: Delta Differential One-way Ranging) for interplanetary navigation is based on a simple but effective idea. Two widely spaced receive antennas simultaneously track a spacecraft and thereby determine the time difference between the time instants at which the signal arrives at the two stations. The art to determine this difference is one-way differential range (DOR). Theoretically, this difference depends only upon the positions of the two antennas and the observed spacecraft. However, there are a number of confounding factors, they must, for example, the radio waves through the troposphere and the ionosphere , they are disturbed by the plasma in the solar wind and the clocks of the base stations are inaccurate. The Delta-DOR method corrects this error by changing the direction of a quasar is used for correction (within 10 °) near the spacecraft.
The direction of the quasar is by prior measurements very accurately known with an accuracy of only 50 billionths of a degree. The distance to the spacecraft is calculated by measuring the time it takes for a radio signal to the probe and to the earth. By measuring the Doppler shift of the signal, the relative velocity along the line of sight is determined. In order to control the spacecraft, however, the real speed is needed in the room. So far, the movement of the probe against the sky background was observed to several days. In principle, the measured signal from the radio of the quasar time difference (the delta subtracted) from the time difference between the spacecraft. The position can be accurately determined with the delta-DOR method, since the error in the measurement of the spacecraft position can be corrected by the similar error in the Quasarposition.
This procedure was applied in the NASA space probe Phoenix and the two Mars Exploration Rovers and the ESA probe Venus Express and Rosetta for use.
Even though I dont know the Quasar ISRO Refers.

plz refer for isro mom mangalyan details at

http://www.isro.org/pslv-c25/pdf/pslv-c25-brochure.pdf
(plz remove space between . pdf)

 

[kurup]

@Aeronaut : Please merge this thread with ISRO sticky .

 

[ptltejas]

today Eureka: Mars Mission Special.
Tonight 7:30 PM on Rajya Sabha TV.