The decision on how many orbits the Lander will make has not yet been taken, but it will be a 100x30 (100km on one side and 30 on the other) elliptical orbit, which means that the entire configuration of the mission has now changed, in effect, causing the delay.“Earlier, the plan was to gradually go down from 100km and reach 18km from the Moon’s surface. From there, the orientation would change, making the Lander go slightly horizontal for about 8.5km and then we were to change the orientation and velocity further to make the soft landing,” a senior member of the Chandrayaan-2 team said.Now, as per the revised plans, the Lander has to go around the surface of the moon before entering the descent phase. Scientists working on the project say that this change in plan could have been avoided as the earlier configuration that was cleared would have achieved the main mission goals.“This additional activity required by the Lander means a host of new hardware added. This is one method of achieving the landing, while the earlier one was another. Our job is to follow what the chairman and other seniors decide and develop things that can successfully complete the mission,” another scientist said.This has also increased Chandrayaan-2 weight from 3,250kg to 3,850kg, which has prompted some changes, including moving to GSLV MK-III instead of the GSLV MK-II, which would have required an uprate to accommodate the additional weight.New configuration & soft landing issueAs per the new configuration cleared after the fourth Comprehensive Technical Review (CTR) meeting held on June 19, among other things, the Lander would require a fifth liquid engine to manage the additional load of having to orbit, along with other hardware including a transponder which it earlier didn’t need.“All these last-minute changes means that we have to test all the new hardware and then begin the fabrication process, which will delay the project. Also, the software algorithms need to change as the mission profile itself has been altered, and even this would need tests,” the scientist said.“The fifth Centrally mounted 800N Steady State Liquid Engine with additional hardware has been included to mitigate upward draft of dust to craft while landing,” the Isro has found.Also, the Lander will have a new Lander Leg configuration with increased base diameter (from 3.6m to 4.34m) which is to improve the stability margins.Why the orbitingAccording to the committee, the Lander is now required to orbit so that it can make “assessment of various system performances before the actual critical Powered,” and to do this, the descent phase requires the inclusion of four reaction wheel and its drive electronics as well as two micro Star Sensors (main & redundant) which will enable it to measure the moving velocity and help land.It will also have transponders for ranging and doppler functions with the antenna configuration and a host of additional supporting systems—power, structure, thermal, etc, will also be added.Besides, there will be two additional propellant tanks (390L capacity), additional pressurant tank (35.5L capacity) among other changes.
No - this to help locate the lander. Its images are compared with previous maps to identify its location, so it can be steered down to a precise landing. This technology has been described before, e.g. by Astrobotic in the US for the Moon and for future Mars landings as well. It will help ensure a safe landing by guiding the lander to the pre-selected safe location.
Probably the LRO images would be used for the terrain map, as they would have 2 or 3 times better resolution. My guess is that the low passes are intended to improve knowledge of the trajectory. Drop to the final pre-descent orbit and make a couple more orbits while the trajectory is checked, then commit to the final descent. Otherwise you are going from the higher orbit to the surface in one go.
Among the key missions to look for in 2019 will be the Chandrayaan-2, Aditya-L1 (India's solar mission) and two demonstration flights of the SSLV (small satellite launch vehicle).
Isro hopes to start the new year (2019) with the launch of Chandrayaan-2, which has already been delayed owing to multiple changes that were needed. Sivan said that they are looking at a launch window between January 3 and mid-March. "We hope to meet the January 3 date," he said, while confirming TOI's August 12 report that the entire configuration of the mission has changed.
The launch of India’s second spacecraft to the Moon has been delayed for the second time this year. Chandrayaan-2 had been expected to lift off in October, after it was pushed back from its original launch date in April.Kailasavadivoo Sivan, chair of the Indian Space Research Organisation (ISRO) in Bangalore, told reporters on 12 August that the agency is aiming to launch the craft on 3 January next year — although the mission has a launch window of any time between January and March. Chandrayaan-2 will carry an orbiter that will travel around the Moon; a lander that will attempt India’s first controlled, or soft, landing; and a rover.Sivan said that there were several reasons for the latest delay, including design changes to ensure a smooth touchdown for the lander. He said these changes have increased the weight of the spacecraft and therefore the amount of fuel needed to complete the mission, which has further added to delays.
NASA's Moon Minerology Mapper hits it big, confirming water ice on the Moon:https://www.nasa.gov/feature/ames/ice-confirmed-at-the-moon-s-polesThe pics seem to show way more ice detected at the South Pole compared to the North Pole - I wonder why. Shouldn't we expect similar apportionment for both poles? What could be the reason for this?I wonder how this could affect the Chandrayaan-2 mission?
Nothing to do with rotation, the answer is topography. The south pole has more craters with permanent shadow in them than the north pole. In the north, many craters are largely filled with ejecta from the Imbrium basin impact, so they are not very deep (e.g. Peary) and don't have much shadow area. In the south, the gigantic South Pole-Aitken basin (extending from Aitken crater at c. 20 degrees south to the South Pole itself) causes lower topography to begin with (plus mountain blocks which cast shadow), and there are other craters in the area to dig even deeper - Shoemaker, Haworth, Faustini, Amundsen, Cabeus to name only the biggest ones. The result is much more permanent shadow in the south, and more opportunities for the ice to collect.Chandrayaan 2 is landing at about 70 degrees south, nowhere near these ice deposits. They will have to wait for future missions.
Indian Space Research Organisation (Isro) will launch its second moon mission 'Chandrayaan-2' carrying an orbiter, a lander and a rover between January 3 and February 16 next year. During a media interaction, Isro chairman K Sivan said, "We have a window of opportunity to launch the mission between January 3 and February 16. We will try our best to launch the mission during this window."He said "Chandrayaan-2 will be the first mission in the world going near the "south pole", where recently Nasa's payload M3 on Chandrayaan-1 discovered ice in the shadow of craters.
The Chandrayaan-2 spacecraft will carry an orbiter, a lander and a rover. The lander carrying a rover will make a soft-landing on the south pole of the moon and the "rover will spend a full lunar day (14 Earth days) there to make the most of the day time performing experiments. "The rover will walk 100 metres and analyse the content of the lunar surface. It will also perform several experiments using payloads it will be carrying. The orbiter and rover will send back photographs of the moon within 15 minutes. The Isro chairman revealed that the "mass of Chandrayaan-2 has been increased to 3.8 tonnes and will be launched by GSLV-MK-III", instead of GSLV Mk II as planned earlier.
Dutch lunar rover missionBy the end of 2018 or in early 2019 a small Dutch lunar rover will travel to the moon.The little 1.5 kg six legged robot will land on the lunar surface and will send images back hometo earth. For this mission the Dwingeloo radio telescope will become ‘mission control’!! Thelaunch will take place in India and on the same launch there will also be an Indian lunar rover. Infact the plan is that the Indian and Dutch lunar rovers will take pictures of each other. It’s a‘proof of concept’ mission. If this is successful a whole ‘swarm’ of little rovers will go to themoon eventually. One planned mission is to build radio antennas to form an array for radioastronomy