Chandrayaan-2 : Updates

Today is the fifth and final Earth bound orbit raising burn of the CY-2. Scheduled to happen between 14:30-15:30 IST or 2:30 PM-3:30 PM IST. The targeted orbit is (221 km X 143585 km).

After this we will have the Trans-Lunar Insertion burn. Scheduled on 14-08-2019, 03:00-04:00 IST. CY-2 is scheduled to reach moon on August 20, 2019.
 
And its done :

August 6, 2019

Fifth earth bound orbit raising maneuver for Chandryaan-2 spacecraft has been performed successfully today (August 6, 2019) at 1504 hrs (IST) as planned, using the onboard propulsion system for a firing duration of 1041 seconds. The orbit achieved is 276 x 142975 km.

All spacecraft parameters are normal.

The next maneuver is Trans Lunar Insertion (TLI), which is scheduled on August 14, 2019, between 0300 – 0400 hrs (IST).

Chandrayaan2 Latest updates - ISRO
 
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Gautam said:
And its done :

August 6, 2019

Fifth earth bound orbit raising maneuver for Chandryaan-2 spacecraft has been performed successfully today (August 6, 2019) at 1504 hrs (IST) as planned, using the onboard propulsion system for a firing duration of 1041 seconds. The orbit achieved is 276 x 142975 km.

All spacecraft parameters are normal.

The next maneuver is Trans Lunar Insertion (TLI), which is scheduled on August 14, 2019, between 0300 – 0400 hrs (IST).

Chandrayaan2 Latest updates - ISRO
Click to expand...

Sir, does the shortfall in apogee any way affect the mission or the efficacy of the TLI burn?
 
vingensys said:
Sir, does the shortfall in apogee any way affect the mission or the efficacy of the TLI burn?
Click to expand...
I frankly don't know enough about orbital dynamics to make any sense of it. But it seems to me, unlike a direct transfer, a Hohmann minimum energy transfer orbit has a lot of room for errors. Remember the first launch getting delayed due to a technical problem with the launcher ? The initial orbits were planned for that launch was thrown out and new ones were brought in. That seemed to have no impact on the mission plan.

Now this is what happened so far :

Date - Event Scheduled during(IST) - Targeted Orbit(km) - Achieved Orbit(km)

24.07.2019 - 14:00 - 15:30 - 230 x 45162 - 230 X 45163
26.07.2019 - 01:00 - 02:00 - 250 x 54689 - 251 X 54829
29.07.2019 - 14:30 - 15:30 - 268 x 71558 - 276 x 71792
02.08.2019 - 14:00 - 15:00 - 248 x 90229 - 277 x 89472
06.08.2019 - 14:30 - 15:30 - 221 x 143585 - 276 x 142975


Notice how every single targeted orbit wasn't achieved. It was always slightly more or less. We saw similar inaccurate orbital attainment during the Mangalyaan too and that worked out just fine. So I think we will be okay, let's see.
 
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Gautam said:
I frankly don't know enough about orbital dynamics to make any sense of it. But it seems to me, unlike a direct transfer, a Hohmann minimum energy transfer orbit has a lot of room for errors. Remember the first launch getting delayed due to a technical problem with the launcher ? The initial orbits were planned for that launch was thrown out and new ones were brought in. That seemed to have no impact on the mission plan.

Now this is what happened so far :

Date - Event Scheduled during(IST) - Targeted Orbit(km) - Achieved Orbit(km)

24.07.2019 - 14:00 - 15:30 - 230 x 45162 - 230 X 45163
26.07.2019 - 01:00 - 02:00 - 250 x 54689 - 251 X 54829
29.07.2019 - 14:30 - 15:30 - 268 x 71558 - 276 x 71792
02.08.2019 - 14:00 - 15:00 - 248 x 90229 - 277 x 89472
06.08.2019 - 14:30 - 15:30 - 221 x 143585 - 276 x 142975


Notice how every single targeted orbit wasn't achieved. It was always slightly more or less. We saw similar inaccurate orbital attainment during the Mangalyaan too and that worked out just fine. So I think we will be okay, let's see.
Click to expand...

While desirable, attaining the orbital figures down to the last decimal is neither easy nor is it necessary.

There is always a defined margin of error and as long as the orbits are within it, there is no problem.
 
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Gautam said:
I frankly don't know enough about orbital dynamics to make any sense of it. But it seems to me, unlike a direct transfer, a Hohmann minimum energy transfer orbit has a lot of room for errors. Remember the first launch getting delayed due to a technical problem with the launcher ? The initial orbits were planned for that launch was thrown out and new ones were brought in. That seemed to have no impact on the mission plan.

Now this is what happened so far :

Date - Event Scheduled during(IST) - Targeted Orbit(km) - Achieved Orbit(km)

24.07.2019 - 14:00 - 15:30 - 230 x 45162 - 230 X 45163
26.07.2019 - 01:00 - 02:00 - 250 x 54689 - 251 X 54829
29.07.2019 - 14:30 - 15:30 - 268 x 71558 - 276 x 71792
02.08.2019 - 14:00 - 15:00 - 248 x 90229 - 277 x 89472
06.08.2019 - 14:30 - 15:30 - 221 x 143585 - 276 x 142975


Notice how every single targeted orbit wasn't achieved. It was always slightly more or less. We saw similar inaccurate orbital attainment during the Mangalyaan too and that worked out just fine. So I think we will be okay, let's see.
Click to expand...

There will always be a delta between the projected/planned orbital parameters and the actual achieved.

There are multiple reasons for this

- micro gravity affect of other celestial bodies on the Orbiter
- this causes nutation and precession of the ecliptic
- the micro-angular vector deflection of the thrust nozzles with respect to the intended vector
- time duration of firing the thursters
- deflection in computational calculations due to the above factors

Also note that unlike maneuvering of Satellites to intended coordinates where 3D space coordinates are achieved after multiple precision firings, this one is simply a gross firing for orbit raising and orbit escaping purpose.

The finer accuracy will be achieved by the lander after being released from the orbiter and in orbiting the moon for several days and slowly descending to the moon's surface with every pass.

Similarly, before release of the lander, the Orbiter itself will be fine tuned to the intended Orbit in several days.
 
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YAY !!:D:D


Chandrayaan-2 Successfully enters Lunar Transfer Trajectory

Aug 14, 2019

The final orbit raising manoeuvre of Chandrayaan-2 spacecraft was successfully carried out today (August 14, 2019) at 02:21 am IST. During this maneuver, the spacecraft's liquid engine was fired for about 1203 seconds. With this, Chandrayaan-2 entered the Lunar Transfer Trajectory. Earlier, the spacecraft’s orbit was progressively increased five times during July 23 to August 06, 2019.

The health of the spacecraft is being continuously monitored from the Mission Operations Complex (MOX) at ISRO Telemetry, Tracking and Command Network (ISTRAC) in Bengaluru with support from Indian Deep Space Network (IDSN) antennas at Byalalu, near Bengaluru. Since its launch on July 22, 2019 by GSLV MkIII-M1 vehicle, all systems onboard Chandrayaan-2 spacecraft are performing normal.

Chandrayaan-2 will approach Moon on August 20, 2019 and the spacecraft's liquid engine will be fired again to insert the spacecraft into a lunar orbit. Following this, there will be further four orbit maneuvers to make the spacecraft enter into its final orbit passing over the lunar poles at a distance of about 100 km from the Moon’s surface.

Subsequently, Vikram lander will separate from the orbiter on September 02, 2019. Two orbit maneuvers will be performed on the lander before the initiation of powered descent to make a soft landing on the lunar surface on September 07, 2019.




Chandrayaan-2 Successfully enters Lunar Transfer Trajectory - ISRO
 
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Gautam said:
YAY !!:D:D


Chandrayaan-2 Successfully enters Lunar Transfer Trajectory

Aug 14, 2019

The final orbit raising manoeuvre of Chandrayaan-2 spacecraft was successfully carried out today (August 14, 2019) at 02:21 am IST. During this maneuver, the spacecraft's liquid engine was fired for about 1203 seconds. With this, Chandrayaan-2 entered the Lunar Transfer Trajectory. Earlier, the spacecraft’s orbit was progressively increased five times during July 23 to August 06, 2019.

The health of the spacecraft is being continuously monitored from the Mission Operations Complex (MOX) at ISRO Telemetry, Tracking and Command Network (ISTRAC) in Bengaluru with support from Indian Deep Space Network (IDSN) antennas at Byalalu, near Bengaluru. Since its launch on July 22, 2019 by GSLV MkIII-M1 vehicle, all systems onboard Chandrayaan-2 spacecraft are performing normal.

Chandrayaan-2 will approach Moon on August 20, 2019 and the spacecraft's liquid engine will be fired again to insert the spacecraft into a lunar orbit. Following this, there will be further four orbit maneuvers to make the spacecraft enter into its final orbit passing over the lunar poles at a distance of about 100 km from the Moon’s surface.

Subsequently, Vikram lander will separate from the orbiter on September 02, 2019. Two orbit maneuvers will be performed on the lander before the initiation of powered descent to make a soft landing on the lunar surface on September 07, 2019.




Chandrayaan-2 Successfully enters Lunar Transfer Trajectory - ISRO
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I read this was to happen around 20 th Aug.
 
_Anonymous_ said:
I read this was to happen around 20 th Aug.
Click to expand...
CY-2 is scheduled to arrive on moon and settle in a lunar orbit on 20th. It has now left earth's orbit and is heading for the moon, the journey will take a few days. This journey will happen in a pre-designated trajectory known as the Lunar Transfer orbit. Everything is on schedule.
 
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Here is a detailed plan from now till Sep 7 when the touchdown happens :

Lunar Bound Phase (20 Aug till 1 Sep) :

> After the LOI, Chandrayaan-2 has an inclination of 88 Degrees
> The orbit achieved is 114 km x 18072 km.
> 4 manoeuvres are planned to put the spacecraft around 100km X 100km orbit
> The manoeuvres will be conducted on August 21(1 PM IST), 28, 30 and September 1 respectively

Lander Orbiter Separation (2 Sep) :

> By Sep 2, Chandrayaan-2 is expected to be in a 114km X 128km orbit when Vikram will separate from orbiter
> A short 3 second health check will be done on Vikram

Deboosting (3 Sep till 6 Sep) :

> On Sep 3, Vikram will perform a de-orbit manoeuvre for 6.5 seconds where its orbit will be 35km X 97km
> Vikram will need to reach a 30km X 100km orbit
> Here Vikram will achieve the planned inclination of 90 degrees

Powered Descend (7 Sep) :

> On Sep 7 at 1.40 am (IST) the powered descent will start
> Vikram will start its descent from a height of 30 km (Speed 6120 km/h)
> A little over 10 minutes and 30 seconds later it will be 7.4 km from the lunar surface (Speed 526 km/h)
> In next 38 seconds, it will reach an altitude of 5 Km from the lunar surface (Speed 331 km/h)
> After another 89 seconds, it will reach an altitude of 400 m from the lunar surface
> Here Vikram will hover for 12 seconds
> It again takes 66 seconds to reach to 100 m altitude from the lunar surface
> Again it will hover for for 25 seconds (Here Vikram decides whether to land or choose an alternate spot)
> If it decides to land on the original spot, it takes 65 seconds to reach a height of 10m
> If it decides to land on an alternate spot, it takes 40 seconds to reach an altitude of 60 m and then again drop to 10 m in next 25 seconds

Landing (7 Sep, 1.55 am IST/ 6 Sep, 8:25 pm UTC) :

> From a height of 10 m to reach the lunar surface, it will take 13 seconds for a soft touchdown
> All five of its engines will be firing during this time, till sensors tell them to shut off once all the four legs of the lander touch the surface
> Moon landing is planned at 1.55 am IST on September 7 ( Sep 6, 8:25 pm UTC)
> Vikram will send back to Earth its first pictures after touchdown some 15 minutes later
> After four hours, Pragyan will crawl out of the lander


@47:45 in the video I posted just above(#178), Dr Sivan is asked about whether the hardware on the lunar surface could be expected to survive through the lunar night, and to function afterwards. @49:05 he says that the hardware has been qualified for survival, but that this could not be guaranteed.


Oh and one last thing. The CY-2 lander landing on lunar surface on 7th Sep will be broadcasted live by Nat Geo and Hotstar.

Chandrayaan 2 | English | 7th September

https://www.indiantelevision.com/te...andrayaan-2-from-isro-s-command-centre-190724
 
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