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LVM3 M4/Chandrayaan-3 Mission:
Mission Readiness Review is completed.
The board has authorised the launch.
The countdown begins tomorrow.
It begins. C3 will mark an epoch in India's quest to launch a rover on the Moon's polar regions. This is an immense and very challenging task. Fraught with many challenges. While wishing India, ISRO & C3 the best, we can track all Chandrayaan 3 activities here.
Personally I do hope that the rover is successful and we find copious amount of water in one of the craters.
The first post launch parameter to check will be the injection orbit after separation from CUS25 - marking it here as 170 +/- 3.5 kms x 36,500 +/- 500 kms and inclination 21.3 deg from the Brochure.
Isro chairman S Somanath told TOI that LVM3 will place Chandrayaan-3 in an apogee (farthest point from Earth) of 36,500km as against 45,475km during Chandrayaan-2. The perigee (closest point to Earth) will be around 170km, nearly the same as last time. “This is being done to get more stability,” he said.
4+1 Earth-Bound Manoeuvres
Another scientist explained: “In Chandrayaan-2, we took the ‘burn to depletion’ — use the last drop of fuel — approach with the cryogenic upper stage to achieve high altitude. However, that creates post-launch tracking challenges given that we use international stations. So, we’ve decided to go to a definitive orbit (36,500km), making initial tracking and operations that follow more efficient.”
Isro will then conduct multiple Earth-bound manoeuvres to increase Chandrayaan-3’s orbit before commands for trans-lunar insertion (TLI) that will kick off the spacecraft’s journey towards Moon, are given. Multiple scientists explained that Isro will perform four major manoeuvres — No 1, 3, 4 and 5 — to raise the apogee, while the second manoeuvre will be a minor perigee-rising one.
TLI Expected On July 31 If all goes as planned, TLI will be done on July 31.
Chandrayaan-3 will then travel towards Moon for about five-and-a-half days and lunar orbit insertion is expected around August 5. These are estimations for nominal performance.
“Spacecraft will initially be on a greater apolune (farthest point from Moon) and we’ll do multiple perilune (closest point) manoeuvres to reduce altitude eventually to a 100km X 100km circular orbit. It’s too early to speak about exact dates for this milestone,” one scientist explained, adding there could be around five lunar-bound manoeuvres before the final descent phase. After Chandrayaan-3 reaches 100km X 100km orbit, the lander module (Vikram & Pragyan) will separate from the propulsion module and be eventually brought to a 100km X 30km orbit, from where commands for deboost and final descent is expected on August 23.
rahulm wrote: ↑10 Jul 2023 14:32
S Somnath on CY2 and CY3. There are many vdo's out there on this topic but in my opinion, in this single vdo, Shri Somnath explains the issues with CY2 and fixes in CY3 well.
This is an AI generated summary. There may be inaccuracies. ·
Summary
"In this YouTube video, the ISRO Chief discusses the issues faced during the Chandrayaan-2 mission and the improvements made for Chandrayaan-3. The primary problems with Chandrayaan-2 included higher thrust from the engines, accumulation of errors, limited maneuverability, and conflicting landing requirements. To address these, Chandrayaan-3 adopts a failure-based design approach by expanding the landing area, providing more fuel, and considering various failure scenarios. The ISRO Chief also mentions the experiments and instruments to be used in Chandrayaan-3, collaboration with Japan on a moon mission, and the need to transfer SSLV technology to the industry."
Details
00:00:00 In this section, the ISRO Chief explains how they have perfected the overall process of reaching the Moon through previous missions but faced challenges during Chandrayaan-2. The primary issues included higher thrust from the engines than expected, accumulation of errors over time, limited ability to make turns, and conflicting requirements for reaching the landing spot with low velocity. To address these problems, they are adopting a failure-based design approach for Chandrayaan-3. They are expanding the landing area, providing more fuel for flexibility, and considering various failure scenarios to protect the mission. The goal is to enhance the craft's ability to handle parameter variation and dispersion.
00:05:00 In this section, the ISRO Chief explains the improvements made for Chandrayaan-3 based on the failures of Chandrayaan-2. The high-resolution camera on board Chandrayaan-2 provided detailed images of the moon's landing site, allowing for better mapping and programming of the landing coordinates. Additional failure modes were also taken into consideration, such as generating power and facing the sun. Extensive testing was conducted, including helicopter flights and simulations of failure scenarios. Unlike Chandrayaan-2, the Orbiter for Chandrayaan-3 does not have scientific payloads, thus reducing costs. The Rover of Chandrayaan-3 will conduct experiments on the composition of the moon's surface and study its minimal atmosphere and electrical and thermal characteristics.
00:10:00 In this section, the speaker discusses the various experiments and instruments that would be used in the upcoming Chandrayaan-3 mission. This includes measuring conductivity and electrical characteristics of the lunar surface, studying vibrations and internal processes, and analyzing the chemical composition of materials. The speaker also mentions plans to collaborate with Japan on a moon mission, although the details are still being worked out. The duration of the Chandrayaan-3 mission would be one Moon day, which is approximately 14 days, and the launch window is expected to start from August 23rd. The speaker assures that weather conditions are being monitored, and there shouldn't be any issues with the launch as of now. The speaker also explains the need to transfer SSLV technology to the industry, as there was no industry capable of developing small rockets in India. The development of SSLV has been completed successfully, and now the focus is on supporting the industry in this field.
00:15:00 In this section, the ISRO Chief clarifies that initially, they had no intentions of developing a small satellite rocket as they were not interested in competing with anyone. Their focus has always been on assisting industries in their development. However, they have now recognized the need for a small satellite launch capability, which is currently being undertaken by the Private Industry.
My comment (not present in the Ai summary) : CY3 is designed for 6-sigma as against 3-sigma for CY2.
sanman wrote: ↑11 Jul 2023 04:22
Good nuts-n-bolts nitty-gritty talk between Gareeb Scientist and ISRO Chairman Somnath on Chandrayaan-3:
I like Somnath's full command of knowledge on all aspects. He is a very good hands-on ISRO chief, immediately able to fluently discuss any and all aspects in expert detail.
Chandrayaan 3 is an ISRO (Indian Space Research Organization) mission with the primary objective of putting a lander and rover in the highlands near the south pole of the Moon in the August 2023 timeframe and demonstrating end-to-end landing and roving capabilities. It will also make a number of scientific measurements on the surface and from orbit. It comprises a lander/rover and a propulsion module. The lander/rover will be similar to the Vikram rover on Chandrayaan 2, with improvements to help ensure a safe landing. It will be carried to lunar orbit by the propulsion module which will remain in orbit around the Moon and act as a communications relay satellite.
Spacecraft and Subsystems
The propulsion module is a box-like structure (modified I-3K structure) with one large solar panel mounted on one side and a large cylinder on top (the Intermodule Adapter Cone) that acts as a mounting structure for the lander. The main thruster nozzle is on the bottom. It has a mass of 2145.01 kg, of which 1696.39 kg is propellant for the MMH + MON3 bi-propellant propulsion system. It can generate 738 W power. Communications is via S-Band and attitude sensors include a star sensor, Sun sensor, and Inertail Reference unit and Accelerometer Package (IRAP).
The lander is also generally box-shaped (200 x 200 x 116.6 cm), with four landing legs and four landing thrusters. It has a mass of 1749.86 kg, including 26 kg for the rover, and can generate 738 W using side-mounted solar panels. The lander has a number of sensors to ensure a safe touchdown, including an accelerometer, altimeters (Ka-band and laser), Doppler velocimeter, star sensors, inclinometer, touchdown sensor, and a suite of cameras for hazard avoidance and positional knowledge. Reaction wheels are used for attitude control, and propulsion is provided by a MMH and MON3 bipropellant system with four 800 N throttleable engines and eight 58 N throttleable engines. An X-band antenna is used for communications. The lander carries the rover in a compartment with a ramp for deployment onto the surface.
The rover is a rectangular chassis, 91.7 x 75.0 x 39.7 cm in size, mounted on a six-wheel rocker-bogie wheel drive assembly. It has navigation cameras and a solar panel that can generate 50 W. It communicates directly with the lander via Rx/Tx antennas.
The lander will carry an instrument called Chandra’s Surface Thermophysical Experiment (ChaSTE) to measure surface thermal properties, the Instrument for Lunar Seismic Activity (ILSA) to measure seismicity around the landing site, the Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere (RAMBHA) to study the gas and plasma environment, and a passive laser retroreflector array provided by NASA for lunar ranging studies. The rover will carry two instruments to study the local surface elemental composition, an Alpha Particle X-ray Spectrometer (APXS) and Laser Induced Breakdown Spectroscope (LIBS). The Propulsion Module / Orbiter will carry one experiment called the Spectropolarimetry of HAbitable Planet Earth (SHAPE) to study Earth from lunar orbit.
Mission Profile
The mission is currently scheduled to launch on 14 July 2023 at 9:05 UT (2:35 p.m. India standard time), with a possibility to launch as late as 19 July, on a GSLV Mark 3 (LVM 3) heavy lift launch vehicle from Satish Dhawan Space Center in Sriharikota, India. It will place Chandrayaan 3 into an approximately 170 x 36,500 km elliptic parking orbit. The propulsion module will bring the lander/rover will into a 100 km circular polar lunar orbit and separate. The lander will then touch down with the rover in the south polar region of the Moon, near 69.37 S, 32.35 E. For the scheduled launch time, touchdown is expected to occur near the end of August. Touchdown velocity is planned to be less than 2 m/s vertical and 0.5 m/s horizontal. The propulsion module / communications relay satellite will remain in lunar orbit to enable communications with Earth. Chandrayaan 2 will also be used as a backup relay. The lander and rover are designed to operate for one lunar daylight period (about 14 Earth days).
rahulm wrote: ↑12 Jul 2023 03:46
K. Sivan speaks on CY2 and CY3
This is an AI generated summary. There may be inaccuracies.
00:00:00 - 00:05:00
Former ISRO chief K Sivan shares insights and progress regarding the Chandrayaan-2 mission and the upcoming Chandrayaan-3 mission. While the landing and roving objectives of Chandrayaan-2 were not successful, valuable telemetry data was gathered during the descent, leading to improvements and corrections for Chandrayaan-3. Lessons learned from Chandrayaan-2 have been applied to enhance redundancy and alternative routes for data collection in Chandrayaan-3, making the system more robust and prepared for future missions. Additionally, K Sivan mentions that while there are no new technologies introduced in Chandrayaan-3 compared to Chandrayaan-2, improvements in technology configuration and a laser Doppler velocity meter sensor aim to increase the mission's chances of success, even in case of obstacles.
00:00:00 In this section, K Sivan, former ISRO chief, discusses the progress and key learnings from the Chandrayaan-2 mission. While the mission had three objectives, the landing and roving parts were not successful. However, a significant amount of telemetry data was collected during the descent, which helped identify discrepancies and errors in the system. These errors have been corrected, and margins and capabilities have been improved for Chandrayaan-3. Lessons learned from Chandrayaan-2 have been applied in all aspects of Chandrayaan-3, including redundancy and alternative routes for data collection. Overall, the system has become more robust and prepared for future missions.
00:05:00 In this section, K Sivan explains that there are no new technologies implemented in Chandrayaan-3 compared to Chandrayaan-2. The mission is a repetition of Chandrayaan-2 with improvements in technology configuration and robustness. The only addition is a laser Doppler velocity meter sensor. The aim is to increase the mission's chances of success even if something goes wrong.
I am deploying with my unit for the annual weekend exercise from tomorrow (Friday). I will be in a no coverage area in the Australian bush and will miss the launch. It will be the first ISRO launch in the last 20 odd years that I will miss. :-(
I will catch up with events upon my return late Sunday.
Until then, all the very best to ISRO and looking forward to reading this thread with updates upon my return to civilisation.
rahulm wrote: ↑13 Jul 2023 03:53
...I am deploying with my unit for the annual weekend exercise from tomorrow (Friday). I will be in a no coverage area in the Australian bush and will miss the launch. It will be the first ISRO launch in the last 20 odd years that I will miss. :-(
First of all stay safe and enjoy your annual weekend exercise with your unit.
C3 has three phases and will go all the way to August 5. So you may miss the excitement of the launch, but that is trivial compared to C3's TLI and even more exciting will be the day when C3 Lander goes for its mission.
if the launch is ho-hum, all parameters naarmal, then you can start preparing for the bigger excitement. Like getting beer for the unit for Aug 5. Like Aug 15 coming earlier.
I am so excited. Will be tracking this launch closely. 3 years from last attempt . I am hoping that all the kinks are worked out and we land and plant our flag!!!!!!.
Ahead of the launch of the Chandrayaan-3 mission, a team of scientists from the Indian Space Research Organisation (ISRO) offered prayers at the Tirupati temple.
The scientists also carried with them a miniature model of Chandrayaan-3.
Chandrayaan-3, the third lunar mission of the Indian space agency, will be launched at 2.30 pm tomorrow (14 July) from Satish Dhawan Space Centre in Sriharikota.
"A team of ISRO scientists team arrive at Tirupati Venkatachalapathy Temple, with a miniature model of Chandrayaan-3 to offer prayers," ANI reported.
Additionally:
Earlier on 10 July, speaking on the sidelines of India Space Congress 2023, ISRO Chairman S Somanath said that the space agency has designed the Chandrayaan-3 after learning from the failure of Chandrayaan-2.
"We were trying to target a landing in a particular spot, closer to the South Pole, that is 70 degrees to the South Pole, and in doing so, we faced certain challenges," Somanath said on Chandrayaan-2.
The five engines responsible for the retardation, or reduction of the velocity, of the Chandrayaan-2 lander "developed a little higher thrust than that was expected," Somanath said.
This was coupled with the lander's desperation to land at its designated spot even when it was still far away, thereby increasing its velocity, which was already very high, even if still within the specifications.
"So, there was a contradictory requirement of reaching to the exact spot and, at the same time, achieve a low velocity. It became mathematically difficult for it to do it in the available time. So, finally, when it actually did it, it was (sic) fell short of almost half a kilometre and the velocity of touch was higher," the ISRO chief said.
As to what needed to be rectified in Chandrayaan-3, Somanath said, "We found that... we must give more flexibility to the craft to handle dispersions, essentially."
"So, instead of success-based design in Chandrayaan-2, we are doing a failure-based design in Chandrayaan-3. What all can fail, and how to protect it — this is the approach that we have taken...," he said.
As for a concrete change, ISRO has expanded the area of landing for the Chandrayaan-3 lander, from 0.5 km x 0.5 km in Chandrayaan-2 to 4 km x 2.5 km in the next instalment.
Last edited by disha on 13 Jul 2023 21:32, edited 1 time in total.
SBajwa'ji, since you are missing Dilbu so much, I have to let you know.
Please do not be heartbroken, Dilbu got Halal'ed., that is, he is now happily married. He is now reporting to a new SHQ and all you and I can do is mention him in dispatches and recommend him for BRF vishisht seva medal.
As for Dilbu'ji, we will wish him best when he argues for his case to his SHQ.
So CY-3 lander is designed on frailty basis.
Actually, he is pointing out it was overspecified with contradictory requirements which caused the crash.
""So, there was a contradictory requirement of reaching to the exact spot and, at the same time, achieve a low velocity. It became mathematically difficult for it to do it in the available time. So, finally, when it actually did it, it was (sic) fell short of almost half a kilometre and the velocity of touch was higher," the ISRO chief said."
Off the two more important for landing was the need to achieve low velocity to preclude a crash.
In another interview, he said there were errors accumulated.
If all goes as per plan, Chandrayaan-3 lander Vikram will touch down on the lunar surface at 5.47pm on August 23, after a 40-day journey, at least two people part of the mission confirmed to TOI.
Final landing planned on August 23 will be tracked by Isro’s Bengaluru station;
Chandrayaan-3, India's third Moon mission, has an added 'desi' element to it. "Unlike Chandrayaan-2, when the landing was tracked through a Madrid (NASA-JPL) station, this time we will track the lander from our Isro Telemetry, Tracking and Command Network (Istrac) station in Bengaluru," said a senior scientist. "As per calculations now, Vikram should land on Moon at 5.47pm on August 23; it may change due to variations in mission profile."
While all of Istrac’s stations will track the Friday launch, spacecraft separation will be captured by stations at Brunei and Biak (Indonesia).
Sorry see-near maulanas I could not sleep last night and even now I am too tensed. 'Parfaarmace naarmal' is all that what I wish to hear.
Chandrayaan 3 will fail onlee.
