Mangalyaan on a trajectory to Mars

truthbetold wrote:Thanks info for posting.

Sevaji,
Congratulations.

indophile wrote:ISRO successfully placed the Mars Orbiter spacecraft on a trajectory to Mars. Right on schedule!

 http://www.deccanherald.com/content/372124/mars-orbiter-successfully-placed-mars.html

rawemotions wrote:

indophile wrote:ISRO successfully placed the Mars Orbiter spacecraft on a trajectory to Mars. Right on schedule!

 http://www.deccanherald.com/content/372124/mars-orbiter-successfully-placed-mars.html

Given that the Japanese Mars Orbiter failed entering Martian Orbit, the four planned course corrections reaching Mars within the window, and the entry into Martian orbit are the next milestones. Hope they have enough fuel left for all the above.

One general question, how does ISRO/NASA or any spacecraft know its position  w.r.to the Solar system, once they cross the earth orbit? They can figure out the distance by sending a signal and measuring the time interval for it to return. But how do they know the exact position ? May be they use relative time difference in the signals the orbiter receives from multiple satellites orbiting the earth and earth itself (we need atleast 3) at different locations and use triangulation ? But even then the coverage would be restricted only to the field of view of these satellites and Earth.

Seva Lamberdar wrote:

rawemotions wrote:

indophile wrote:ISRO successfully placed the Mars Orbiter spacecraft on a trajectory to Mars. Right on schedule!

 http://www.deccanherald.com/content/372124/mars-orbiter-successfully-placed-mars.html

Given that the Japanese Mars Orbiter failed entering Martian Orbit, the four planned course corrections, reaching Mars within the window, and the entry into Martian orbit are the next milestones. Hope they have enough fuel left for all the above.

One general question, how does ISRO/NASA or any spacecraft know its position  w.r.to the Solar system, once they cross the earth orbit? They can figure out the distance by sending a signal and measuring the time interval for it to return. But how do they know the exact position ? May be they use relative time difference in the signals the orbiter receives from multiple satellites orbiting the earth and earth itself (we need atleast 3) at different locations and use triangulation ? But even then the coverage would be restricted only to the field of view of these satellites and Earth.

Good question. 
You send a radio signal to the satellite or space probe (e.g. MOM) from Earth and wait for the signal to bounce off the satellite (probe) and return to Earth. By knowing the total time (back and forth for the signal) elasped (T), you can calculate the distance of the space probe from Earth (T*c/2, c= speed of light or signal). You repeat this process a number of times (let's a say 20), and gather (20) data points (locations) in space for space probe at 20 different times (average of when you send and receive the signal). You can then create a plot (time versus location) for the space probe, giving you the trajectory of the probe (including its speed in space). From this info. about trajectory of probe, you extrapolate where the spacecraft (probe) will be in 9 or 10 months. You may even make corrections to the path (trajectory, orbit) of probe if necessary.

rawemotions wrote:

Seva Lamberdar wrote:

rawemotions wrote:

indophile wrote:ISRO successfully placed the Mars Orbiter spacecraft on a trajectory to Mars. Right on schedule!

 http://www.deccanherald.com/content/372124/mars-orbiter-successfully-placed-mars.html

Given that the Japanese Mars Orbiter failed entering Martian Orbit, the four planned course corrections, reaching Mars within the window, and the entry into Martian orbit are the next milestones. Hope they have enough fuel left for all the above.

One general question, how does ISRO/NASA or any spacecraft know its position  w.r.to the Solar system, once they cross the earth orbit? They can figure out the distance by sending a signal and measuring the time interval for it to return. But how do they know the exact position ? May be they use relative time difference in the signals the orbiter receives from multiple satellites orbiting the earth and earth itself (we need atleast 3) at different locations and use triangulation ? But even then the coverage would be restricted only to the field of view of these satellites and Earth.

Good question. 
You send a radio signal to the satellite or space probe (e.g. MOM) from Earth and wait for the signal to bounce off the satellite (probe) and return to Earth. By knowing the total time (back and forth for the signal) elasped (T), you can calculate the distance of the space probe from Earth (T*c/2, c= speed of light or signal). You repeat this process a number of times (let's a say 20), and gather (20) data points (locations) in space for space probe at 20 different times (average of when you send and receive the signal). You can then create a plot (time versus location) for the space probe, giving you the trajectory of the probe (including its speed in space). From this info. about trajectory of probe, you extrapolate where the spacecraft (probe) will be in 9 or 10 months. You may even make corrections to the path (trajectory, orbit) of probe if necessary.

I am sorry but I did not follow. You get an estimate of the distance each time you measure the time interval, but even if I get it 20 more times for a traveling object, how do I use that to get an unambiguous reading of its location? If I am at the centre of a circle/sphere, I can think of many points in space all around the centre, which will satisfy the measured time interval.

rawemotions wrote:

Seva Lamberdar wrote:

rawemotions wrote:

indophile wrote:ISRO successfully placed the Mars Orbiter spacecraft on a trajectory to Mars. Right on schedule!

 http://www.deccanherald.com/content/372124/mars-orbiter-successfully-placed-mars.html

Given that the Japanese Mars Orbiter failed entering Martian Orbit, the four planned course corrections, reaching Mars within the window, and the entry into Martian orbit are the next milestones. Hope they have enough fuel left for all the above.

One general question, how does ISRO/NASA or any spacecraft know its position  w.r.to the Solar system, once they cross the earth orbit? They can figure out the distance by sending a signal and measuring the time interval for it to return. But how do they know the exact position ? May be they use relative time difference in the signals the orbiter receives from multiple satellites orbiting the earth and earth itself (we need atleast 3) at different locations and use triangulation ? But even then the coverage would be restricted only to the field of view of these satellites and Earth.

Good question. 
You send a radio signal to the satellite or space probe (e.g. MOM) from Earth and wait for the signal to bounce off the satellite (probe) and return to Earth. By knowing the total time (back and forth for the signal) elasped (T), you can calculate the distance of the space probe from Earth (T*c/2, c= speed of light or signal). You repeat this process a number of times (let's a say 20), and gather (20) data points (locations) in space for space probe at 20 different times (average of when you send and receive the signal). You can then create a plot (time versus location) for the space probe, giving you the trajectory of the probe (including its speed in space). From this info. about trajectory of probe, you extrapolate where the spacecraft (probe) will be in 9 or 10 months. You may even make corrections to the path (trajectory, orbit) of probe if necessary.

I am sorry but I did not follow. You get an estimate of the distance each time you measure the time interval, but even if I get it 20 more times for a traveling object, how do I use that to get an unambiguous reading of its location? If I am at the centre of a circle/sphere, I can think of many points in space all around the centre, which will satisfy the measured time interval.

MaxEntropy_Man wrote:

rawemotions wrote:

Seva Lamberdar wrote:

rawemotions wrote:

indophile wrote:ISRO successfully placed the Mars Orbiter spacecraft on a trajectory to Mars. Right on schedule!

 http://www.deccanherald.com/content/372124/mars-orbiter-successfully-placed-mars.html

Given that the Japanese Mars Orbiter failed entering Martian Orbit, the four planned course corrections, reaching Mars within the window, and the entry into Martian orbit are the next milestones. Hope they have enough fuel left for all the above.

One general question, how does ISRO/NASA or any spacecraft know its position  w.r.to the Solar system, once they cross the earth orbit? They can figure out the distance by sending a signal and measuring the time interval for it to return. But how do they know the exact position ? May be they use relative time difference in the signals the orbiter receives from multiple satellites orbiting the earth and earth itself (we need atleast 3) at different locations and use triangulation ? But even then the coverage would be restricted only to the field of view of these satellites and Earth.

Good question. 
You send a radio signal to the satellite or space probe (e.g. MOM) from Earth and wait for the signal to bounce off the satellite (probe) and return to Earth. By knowing the total time (back and forth for the signal) elasped (T), you can calculate the distance of the space probe from Earth (T*c/2, c= speed of light or signal). You repeat this process a number of times (let's a say 20), and gather (20) data points (locations) in space for space probe at 20 different times (average of when you send and receive the signal). You can then create a plot (time versus location) for the space probe, giving you the trajectory of the probe (including its speed in space). From this info. about trajectory of probe, you extrapolate where the spacecraft (probe) will be in 9 or 10 months. You may even make corrections to the path (trajectory, orbit) of probe if necessary.

I am sorry but I did not follow. You get an estimate of the distance each time you measure the time interval, but even if I get it 20 more times for a traveling object, how do I use that to get an unambiguous reading of its location? If I am at the centre of a circle/sphere, I can think of many points in space all around the centre, which will satisfy the measured time interval.

i don't know how this is done, but i have a hunch that they make use of the doppler effect.

Rishi wrote:

MaxEntropy_Man wrote:

rawemotions wrote:

Seva Lamberdar wrote:

rawemotions wrote:Given that the Japanese Mars Orbiter failed entering Martian Orbit, the four planned course corrections, reaching Mars within the window, and the entry into Martian orbit are the next milestones. Hope they have enough fuel left for all the above.

One general question, how does ISRO/NASA or any spacecraft know its position  w.r.to the Solar system, once they cross the earth orbit? They can figure out the distance by sending a signal and measuring the time interval for it to return. But how do they know the exact position ? May be they use relative time difference in the signals the orbiter receives from multiple satellites orbiting the earth and earth itself (we need atleast 3) at different locations and use triangulation ? But even then the coverage would be restricted only to the field of view of these satellites and Earth.

Good question. 
You send a radio signal to the satellite or space probe (e.g. MOM) from Earth and wait for the signal to bounce off the satellite (probe) and return to Earth. By knowing the total time (back and forth for the signal) elasped (T), you can calculate the distance of the space probe from Earth (T*c/2, c= speed of light or signal). You repeat this process a number of times (let's a say 20), and gather (20) data points (locations) in space for space probe at 20 different times (average of when you send and receive the signal). You can then create a plot (time versus location) for the space probe, giving you the trajectory of the probe (including its speed in space). From this info. about trajectory of probe, you extrapolate where the spacecraft (probe) will be in 9 or 10 months. You may even make corrections to the path (trajectory, orbit) of probe if necessary.

I am sorry but I did not follow. You get an estimate of the distance each time you measure the time interval, but even if I get it 20 more times for a traveling object, how do I use that to get an unambiguous reading of its location? If I am at the centre of a circle/sphere, I can think of many points in space all around the centre, which will satisfy the measured time interval.

i don't know how this is done, but i have a hunch that they make use of the doppler effect.

The total Doppler effect may therefore result from motion of the source, motion of the observer, or motion of the medium.

>>> Can you please give me an example of where the motion of medium is involved?