Vikram Lander Soft Landing Experiment − Event Analysis

We all have been anxiously waiting to know what has happened to Vikram Lander during the last few minutes before its touch down on Moon's surface. Here I'm going to take up a small exercise to deduce whether or not Vikram Lander will ever be communicable. This attempt is to decode the event to study possibilities from the perspective of a curious student of science. It's not a failure analysis or root cause analysis as such analyses need a more detailed event data that has been obtained till loss of communication.

The experiment by ISRO is an extremely challenging one. Great missions bring greater challenges. Naturally, at each stage, there involved the risk of falling short somewhere. Despite that what ISRO's team has been able to achieve is truly incredible. They have taken a leap of faith. The interest that this experiment has kindled in young minds is invaluable and its intangible benefits will remain unparalleled in near future.

In true sense, the exercise at hands today is more about dispassionately appreciating the basic physics of the event based on limited data available through live telecast and of course wikipedia.

Mass 1471 kg (source: wiki)
Last velocities reported
Horizontal velocity Vh 48.1 mps,
Vertical velocity Vv -59 mps,
Altitude 0.335 km, 1.09 km left before touch down. (Source: recording of live telecast of the event from mission control room by DD National)

Absolute velocity V 78.84 mps, 276.6 kmph
Lander moving at an angle of 51° with moon surface.

Kinetic energy KE possesser by lander = 0.5mV2
= 4,342,392 J = 4242.392 kJ

Moon's gravity 1.62 m/s2 (mostly not used in calculations being a small value)

Approximate time to descend to surface at constant vertical velocity
= 335 m/59 mps = 5.68 s

Required time with available thrusters is way higher than available time if no resistive force is present to reduce velocity of the descending lander.

Required magnitude of constant force opposing the motion of lander in bringing the lander to rest in 5.68 seconds
= 4242.392 kJ ÷ 335 m = 12.66 kN
Force needed at each thruster
= 12.66 kN ÷ 4 = 3.17 kN

Required acceleration (negative)
= −12.66 kN ÷ 1471 kg
= − 8.61 m/s2, which is plausible if orientation of lander is proper.

Considering the information that is coming in recently, the lander lost the orientation and leading to less effective braking. Also the horizontal velocity was seen to have diminished fast and vertical velocity had seen a significant rise. This was evident from the trajectory deviation. They probably assisted descent also. The last visual of the graph of trajectory showed the descent was fast going close to vertical. This reinforces the suspicion that the lander had lost orientation and thrusters were becoming less effective. This means the lander dived into moon surface at a velocity of around 280 kilometres per hour (approximately adding effect of moon's gravity) thus leaving hardly any hope for its equipment to remain undeformed and functional - communication antennas included. Imagine a formula one car crashing into a large concrete block at 280 kilometers per hour. Will we consider repairing the remains, that once made the car seen before impact? More likely than not, the answer will be No. After eliminating least probable scenario, the only scenario is left with us according to which the lander dug into moon's surface to some extent if the surface at point of first contact was soft enough. Also it's likely that it would have tumbled along surface several times before coming to halt.

It's a sure thing that ISRO's team, which is in possession of telemetry data till 335 meter, in my opinion, doesn't expect to establish communication with lander. It'll be a miracle if they do!

...

The woods are lovely, dark and deep,
But I have promises to keep,
And miles to go before I sleep,
And miles to go before I sleep.
- Rober Frost (1874-1963)

Musings on flood affected brothers and sisters

Western Maharashtra is facing extreme flood situation and almost half a million population is directly affected. There is a great deal of anxiety and anger present in the affected region over the hardship these people are undergoing. On the other hand these people have shown remarkable resilience in facing such hardship and loss and have joined hands with each other and government machinery in rescue and the first stage relief operations. Countless people in affected and unaffected areas are working round the clock behind the scene; sometimes even putting their health at risk. There is growing debate on why the problem of such extreme flooding has arisen and which factor is responsible for this.

From illegal constructions and farming near rivers, clogging by plastic waste, excessive rainfall, presence of Alamatti Dam on River Krishna to lack of coordination between governments of Maharashtra and Karnataka are being discussed as some of the main reasons behind these floods. In this brief article, we will go through some of these reasons in order to assess their role in causing the floods.

Among these reasons, the claimed reason of alleged lack of coordination between the governments has a political connotation and hence it is not considered within the scope of present discussion.

On the onset, I would like to say that no single factor alone can lead to the calamity of such scale. It is always a combination of a few or several factors result in such event od such magnitude.

The effect of Alamatti Dam can be ignored in case the level was maintained as per studies carried earlier. Or, to say the least, effect of the presence of Alamatti Dam can be considered less significant though I personally believe otherwise. In my opinion, every resistance to flow on the downstream side potentially increases swelling on the upstream side in the requisite amount. However I do not have quantitative insight and I hereby go with the outcome of hydrological studies reportedly carried out by a joint team of experts in the past. And also unprecedented rainfall in catchment area, which is upstream of flooded region, is another factor which supports the argument of not treating the construction of a dam on the downstream side as a significant reason.

Other major factors for flooding are amount of rainfall, depth and width of riverbed, slope of plains with other geographical aspects.
Now the most important aspect is the population affected by flooding. Wise way to deal with this is to keep population out of the floodline marked by historically highest flood water level. And this is where we are failing time and over again. And when I say population I also mean the use of land within floodline for agriculture as it has potential to raise hydrodynamic resistance to water flow.

Now let us look specifically at the flooding that has taken place. Here we are talking about six to eight hundred percent excess rainfall within a span of six to eight days. This sounds to be the most significant single reason behind the flooding of such catastrophic scale. This factor is unstoppable for ordinary mortals. At the maximum, a qualitative intimation of very high rainfall can be given to the people living near rivers. However in absence of localised judicial studies, exact area under influence of floods cannot be predicted precisely.

Hence the unprecedented rainfall became the cause for extreme hardship that people in rural area underwent in last two weeks. Most of them were living inside their respective village boundary which was in most cases a couple of kilometers away from river. They had not done anything wrong. Just that the flood water breached the long trusted border between human and the river and they were trapped badly.

It must be borne in our mind that no matter how strong you are, you cannot stand the fury of nature. Only way to save yourself is to stay away; far away! That is why certain rules and regulations in town planning are put in place. This is where the role of construction between 100 year floodline and 25 year floodline (red line and blue line respectively) comes into picture. This construction exposes its inhabitants to deadly flooding. Builders and inhabitants look at this risk of suffering from flood based on their knowledge of probability of occurrence of flood at their property. Often this knowledge is shallow and is based on hearsay and never on facts. But the old guard's ways, i.e. planning for the worst, is overlooked. Worldly wisdom is forgotten. Construction plans in risky and restrictive zones are proposed. They are somehow approved by local authority. This local authority usually is oblivious to the involved risk. The nexus straightaway puts the people residing in buildings in restricted zone into grave danger of facing hardship due to flooding at least once in their life time. This increases the flood affected population.

Going by the recent reports, 20 to 25 percent people affected during the current flood situation in Western Maharashtra lived in the restricted zone. This is certainly alarming. Had such illegal constructions been avoided, the number of flood affected population would have reduced to its three fourth.

In this context, government, at least now, should ensure strict enforcement of rules by local authority. On the other hand, citizens need to be sensitized for not purchasing properties in restricted zones and create backward pressure on the builders so that they realise that their buildings if not legally located in safe zone will not be sold. No builder will overlook this aspect if this awareness of potential customers becomes reality.

Also important is the issue of lack of awareness in population of the potential risks of severe flooding. This was the reason why a large number of people across the affected region when requested by volunteers, local administration and NDRF refused to vacate their houses. The reluctance of these people to move to safer area or relief camps multiplied the hurdles in rescue work. This also delayed rescue efforts. However timely and voluntary evaluation done by a large section of flood affected people, those who have shown reasonabilty and courage of the highest order is commendable. Their patience in getting relief or in getting essential provisions and food made the giant effort by rescue teams and volunteers worth the risk.

There is discussion among general public how such flooding can be altogether avoided by construction a canal network that bypasses excess water from catchment areas away from the populated places. This idea reached many people through interview of widely respected social worker Shri Sambhaji Bhide, popularly known as Guruji, given to a few television channels wherein he appealed the state government to explore such means after due studies. It is to be seen how much traction such suggestions can gain in bureaucratic functioning of governments. But if proven feasible in this region, idea of canal network remains an attractive flood mitigation measure in case of extreme high rainfall like this month.

Now relief operation by government is in full swing. Assessment of loss itself will take some time. Chief Minister of Maharashtra has announced immediate release of financial aid to flood affected people. However the next stage of relief and rehabilitation is going to be an uphill task. I strongly recommend voluntary contribution to CM Relief Fund through its official website. Considering a large number of people from some places in states likes Karnataka, Kerala and Gujarat also are suffering from floods, considering The Prime Minister's Relief Fund for making contribution also is a welcome idea.

In the end, it needs to be emphasized that calamity arising out of such flooding can be faced only with a firm control on building plan approval process, proactive town planning, creation of new settlements at safe places and creating more awareness on how a common man should respond to such calamity. At a time when rainfall pattern is changing, if appropriate steps are not taken now, this region is bound to see such calamities only more often.

Musings over law studies

In last few days I am pondering over my ignorance for law studies I have had in the past. It is such a wonderful domain to study if one prepares himself to make the reading a habit. Although I am fond of reading, Law as the subject of study had never appealed me until very recent. I was always told by my friends in this field that they had to remember innumerable clauses and sub-clauses all the time and reproduce the 'right' clause at any time. Most of their energy was consumed in that activity and many of them were completely possessed by the fear of forgetting a clause or two. It was horrible! By that exclamation, I mean, I felt that the exercise of testing my memory, in case I were in their shoes, could be nothing less than a horrible experience! Whole prospect sounded unattractive. But then, in last few years, as I was growing up (read my brain) and when I read a few pieces in the constitution of India, a realization dawned upon me that studying law was interesting, rather damn interesting exercise. Myself being an ardent science follower, it was not going to be the mainstream activity for me. It will never be in future either. But today I have realized that some basic knowledge of the law and judiciary system is must for me as an element of the society. Similarly, in my opinion, it is necessary for all of us to understand this system.

I feel, studying law will become easier if one considers that law is driven by logic, kind of a rational logic. 'viveka', pronounced as विवेक in Sanskrit, Hindi, Marathi and also in probably a few other Sanskrit-derivatives. It will immensely help the student of law if he decides not to be driven by impulses of swaying mind. This impulse, I think, is different from intuitiveness of the mind. Intuition gives the mind a direction, logical and desired during those circumstances, without going through the elaborate process of decision making. In the following paragraphs, I will try to analyze how in normal circumstances decisions are arrived at. I will also try to list the steps in order to elaborate this point.  And in the end, I will try to relate the usefulness of being good at decision making to study law.

The process of the brain's decision making follows the course of the steps listed below.

• Searching the data in form of information held by the brain,
• Collating relevant pieces,
• Forming and comparing alternatives,
• Applying best of the available criterion, and
• Finally making a choice.

The above steps can be elaborated with a more comprehensive structure of sub-steps. I have not ventured into that for the sake of brevity. As I have mentioned earlier, the decisions are not merely taken via this process, but they are arrived at through a carefully formulated methodology. In the present context, we can safely consider this methodology as the logic. Coming back to the intuition, I would like to mention that the intuition can bypass one or more steps in the above list. At times it can lead to the final step straight away. It also helps when none of the bits and pieces of information available is concerned with the circumstances leading to non-existence of the foundation on which the decision is to be arrived at. Intuition leads the mind in such uncertainty. A stable but brave mind can adapt the thought suggested by intuition and also can start following it. But this is where the real danger lies. Such following will yield disastrous results if the path directed by the intuition-led decision turns out to be a wrong one at a later stage. On the other hand, if the intuition-led course is followed with utmost caution and the new circumstances are continuously examined and correctness of the course is verified, we are safely lead to the desired destination more likely than not. Impulsive mind lacks these qualities, caution and the analytical quality of intuitive mind, and often leads to disappointing results.

Student of law can not rely upon intuitive thinking alone. He has to master the decision making process. He will be greatly benefited by intuition of the right kind if the results of the meticulously arrived decision and his intuition coincide. Such occurrence surely has huge potential to boost his confidence. This quality can be of vital importance to the lawyers, judges, law-makers and the law enforcement agencies; not to forget the curious students like you and me.

'viveka' of the law student plays an important role in this process. It helps while working on almost all the steps. It is worth noting here that this quality does not have alternative especially in deciding which of the pieces of information are relevant and also in deciding the criterion for evaluating different alternatives or possibilities found plausible. The student whose mind is occupied with the continuous quest for finding the truth is certain to have this quality. In other words, this quality comes naturally with the desire for the quest for truth.

Having discussed about the basic qualities to study law I will briefly touch upon how law is looked upon in the real world. Law is considered to be a system of rules, usually enforced through a set of institutions. Law shapes almost every sphere of life like politics, economics and society in numerous ways. It serves as a primary social mediator of relations between people. I have borrowed this definition of law from wikipedia originally phrased by legal philosopher H.L.A. Hart. This also prompts the student to have fundamental knowledge of the various spheres of life like a few listed above. This is where the mention of first quality, the habit of reading, comes into picture. It also helps in studying various cases and verdicts delivered in the past. Basic element of the society is a human being. Thus being a good observer of people and events also becomes essential for the student of law. Today being up to date about latest happenings has no longer remained difficult due to advanced print and electronic media and also due to widespread world wide web.

To sum the things up, I would like to say that studying law is an interesting and pleasant challenge for any curious intellectual. Events and their repercussions in society are good triggers for invoking interest in law studies. Also these studies have become a necessity for the professionals not as a part of acquiring general knowledge but to actually set up a regulatory framework for various transactions in their own organizations. Thus the student of law, how ever part time his studies could be, need to have a few qualities namely: liking for reading, logical and analytical ability, 'viveka', methodical decision making ability coupled with intuitiveness, hunger for knowledge, an urge to find truth and last but not the least, a lot of patience. Here I will conclude with a hope that every thing that I have tried to tell myself till this word will motivate myself to spend more time studying law.

*** ***