Chandrayaan adds a little good cheer! Well done, ISRO!

The news that Chandrayaan-I has sent back scientific data as intended is excellent.  ISRO has my warm congratulations at last! Iron is apparently very abundant in lunar rock so discovering it is not revolutionary but even so, the fact India has a successful lunar orbiter which is sending back signals and scientific data is simply delightful. It brings good cheer in a season marred by the Mumbai massacres and the clouds of war.

On November 9 2008, I had incidentally diagnosed the basis of my own earlier pessimism about Chandrayaan as follows, reproduced here again:
“I have been very pessimistic about Chandrayaan-I’s prospects and I am delighted to hear ISRO say it has been successful in placing the spacecraft in lunar orbit.   I have had to wonder where, precisely, my pessimism was mistaken.  The answer is that I had completely left out in my thinking the vast technological progress that has taken place in telecommunications  and telemetry in the last 40 years.  I had surveyed the history of similar attempts by the USSR and USA in the 1960s and that was a history littered by failures of  many sorts.    Let aside rocket-launch failures, the other main sources of failure were in trajectories and in communications.  I have been deeply concerned that India was simply going to fall in the same pitfalls along the way.   But  what I neglected was that our attempt was being made forty years  later and the world has seen enormous technological progress during that time, especially in telecom.  The Soviet and American missions took place in the early 1960s when, for example, colour television hardly existed.  Today, in 2008, ISRO seems to have managed control and guidance systems that have been up to the (very complex) task of placing the spacecraft in lunar orbit.  Hats off to ISRO if it turns out they have succeeded, and cheers if they actually manage to get the scientific data they have wished to receive.

The same mistake that I made here in a  field not my own is what I have myself pointed out being made  in a different context regarding the current world financial crisis. Viz., I said in my September 18 2008 Business Standard article “October 1929? Not!” that the world since the 1929 stock market crash had witnessed so much technological progress that the current crisis could not be compared to the one back then.”

Hats off to all at ISRO!

Subroto Roy

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Excuse me, but ISRO’s self-congratulation is absurdly premature!

Author’s Note, December 28 2008:  This post of mine has been superceded ex post facto by the following text:

Chandrayaan adds a little good cheer! Well done, ISRO!

The news that Chandrayaan-I has sent back scientific data as intended is excellent.  ISRO has my warm congratulations at last! Iron is apparently very abundant in lunar rock so discovering it is not revolutionary but even so, the fact India has a successful lunar orbiter which is sending back signals and scientific data is simply delightful. It brings good cheer in a season marred by the Mumbai massacres and the clouds of war.

On November 9 2008, I had incidentally diagnosed the basis of my own earlier pessimism about Chandrayaan as follows, reproduced here again:
“I have been very pessimistic about Chandrayaan-I’s prospects and I am delighted to hear ISRO say it has been successful in placing the spacecraft in lunar orbit.   I have had to wonder where, precisely, my pessimism was mistaken.  The answer is that I had completely left out in my thinking the vast technological progress that has taken place in telecommunications  and telemetry in the last 40 years.  I had surveyed the history of similar attempts by the USSR and USA in the 1960s and that was a history littered by failures of  many sorts.    Let aside rocket-launch failures, the other main sources of failure were in trajectories and in communications.  I have been deeply concerned that India was simply going to fall in the same pitfalls along the way.   But  what I neglected was that our attempt was being made forty years  later and the world has seen enormous technological progress during that time, especially in telecom.  The Soviet and American missions took place in the early 1960s when, for example, colour television hardly existed.  Today, in 2008, ISRO seems to have managed control and guidance systems that have been up to the (very complex) task of placing the spacecraft in lunar orbit.  Hats off to ISRO if it turns out they have succeeded, and cheers if they actually manage to get the scientific data they have wished to receive.

The same mistake that I made here in a  field not my own is what I have myself pointed out being made  in a different context regarding the current world financial crisis. Viz., I said in my September 18 2008 Business Standard article “October 1929? Not!” that the world since the 1929 stock market crash had witnessed so much technological progress that the current crisis could not be compared to the one back then.”

 

Hats off to all at ISRO!

Subroto Roy

The original text was as follows:

 

Chandrayaan-1 had not completed a single “parking orbit” around Earth (in fact had just reached the atmosphere above Indonesia) before a dozen scientific bureaucrats at ISRO were pouring forth self-congratulations in front of TV cameras — and Indian television news media, including the privately-owned NDTV, were proclaiming “Moon Mission Successful”!

Hello, hello, ISRO and Indian journalists: all of you need a serious reality-check!

Of course India has put satellites into terrestrial space which has been wonderful for telecommunications etc.

But that is not what the present mission is purportedly about.

Please wait until we have managed to get Chandrayan

to escape Earth’s gravity,

reach the Moon’s vicinity,

not crash into the Moon,

or miss it altogether,

(I leave out getting into lunar orbit itself, let aside transmit any data from lunar orbit)

before all the self-congratulations.

No one should want to contribute, after all, to what might still be seen as a large and expensive Government of India publicity/propaganda stunt.   Remember that credibility is all important to the good scientist.  (Just because New Delhi may be delusional does not mean all-India needs to be so as well.)

Subroto Roy, Kolkata

My Subjective Probabilities on India’s Moon Mission

[Author’s Note December 29 2008: Please see my ‘Chandrayaan adds a little good cheer! Well done ISRO!”  — as a good Bayesian would, I  have had to update my subjective probabilities ex post and gladly so!]

The subjective probability I would place on the odds

of our Moon rocket leaving earth orbit successfully is 20:1 against,
of it reaching the moon’s vicinity about 50:1 against,
of it entering lunar orbit successfully about 100:1 against,
and of it transmitting half the data it is intended to about 200:1 against.

Going to the Moon requires a spacecraft reach an “escape” velocity of some 40,000 km per hour. After some 324,000 km, the craft escapes Earth’s gravity and comes to a “standstill” or “neutral” point, a fictional station on the Earth-Moon axis, still some 32,000 km (about 19 Moon radii) away from the Moon. The Moon’s gravity then gradually takes over, drawing the spacecraft faster and faster towards the Moon, to either land on its surface or go into orbit around it, though to avoid a fatal impact crashing into the Moon, the spacecraft may require retrorockets to slow itself down.

All Indians will be delighted if the Moon-launch  tomorrow is successful. At the same time, all Indians, especially millions of wide-eyed children, will be more than disappointed if ISRO’s plans fail through avoidable error.  It was of the highest national importance to try to ensure beforehand that the Indian mission succeeded if it is going to be tried at all.  That has not taken place.

The numerous sources of possible failure include

(A) launch-failure causing the spacecraft to never reach, let aside exit from, terrestrial space onto a path to the Moon, all through belts of intense heat and radiation;

(B) trajectory-failure causing the spacecraft to move wrongly through cislunar and translunar space, miss the Moon and go into solar orbit like everything else in the solar system;

(C) failing to enter lunar orbit, crashing into the Moon instead;

(D) failing to transmit intended data from lunar orbit.

Only if all these and more are avoided, can ISRO’s Moon mission be considered successful.

Here are some questions the PM and his Government needed to answer before the liftoff but failed to do so:

1. Is there an indigenous rocket powerful enough for a spacecraft to reach 40,000 kmph, the escape-velocity from Earth’s gravity?  If a foreign rocket is being used in whole or in part, what are the terms of collaboration?

2. India’s will be mankind’s 85th mission to the Moon on record and there  was a vast amount of publicly available knowledge already gained in other countries; did ISRO do a survey of all previous Moon missions by other countries, especially the USSR and USA since 1957 to investigate and analyse the numerous errors and failures they made?  If not, why did it not do so ?  If we did absorb all existing lessons available, and there are people at ISRO wholly conversant with what went wrong with every case of launch-failure, trajectory-failure, instrumentation-failure causing spacecraft to fail to reach or leave Earth orbit, or miss the Moon, or fail to communicate etc, what identifiable improvements did this learning cause in our Mission-planning?  The cause of nationalism is not served if we repeat the known mistakes of others;  why were we made to feel so confident we were not headed to be making the same mistakes as had been already made by others?

3. It is a blow to national prestige and self-confidence if there is failure at any stage of this difficult enterprise and it may have been better to do the job in discrete and successful stages or not do it at all than fail at it most spectacularly; was any thought given to breaking down the present aim into several stages – e.g., improving rocketry to aim at a “parking orbit” around Earth permitting ground control to better calculate trajectories to the Moon, then to flyby the Moon, then to attempt to go into lunar orbit? Why are scientific payloads being planned to be carried even before we have gained any experience in successful rocketry through terrestrial, cislunar, translunar and lunar space?

4. Our country has not been a major manufacturer of engines, aircraft bodies, computers or communications and imaging equipment, all vital to this enterprise; did we import the components to be used and if so, which ones?

5. Science is universal, and belongs to all mankind; all mundane international disputes appear petty when seen from selenocentric space which is the one good reason to want to try to reach it; why not release into the public domain for scrutiny by everyone in the country and the world the equations involved in the rocketry, and even whether Newtonian or Einsteinian frames of reference are being used?

Subroto Roy
Kolkata, October 21 2008