I read both. Class notes were more in-depth, had entertaining anecdotes but I found Zero To One to be more clear and concise explanation of Peter Thiel's thesis.
The diagrams are MUCH better in Zero To One - the class notes had slightly unwieldy prose to convey the same concepts without using diagrams at times.
All that said, I preferred the class notes. Reading Zero To One I personally felt I didn't get much from it that wasn't in the original notes. I find it a little surprising that it took a whole 18 months to have a rehash of the notes released.
(I posted a similar comment a few months ago. To be clear I have nothing against the India, its space program or its achievements, but it's impossible to discuss the low price of the mission without discussing the elephant in the room)
There is clear lack of sterilization techniques being used on the ISRO spacecraft. This is clearly visible in the public photos and videos. NASA spend a great deal of time and sterilizing deep space probes to reduce the chance of Earth microbes colonizing a place like Mars, or a moon of Jupiter, but ISRO does not.
This comment has nothing to do with India, ISRO, politics or Mars, but I am curious if anyone with expertise can comment on the clean room practices seen applied in this video. Is it odd that the workers don't have on full 'bunny' suits and have (what seems to be) a relatively large amount of skin/hair unprotected? I don't know if it matters that much, it just seems a little lax given the cost of failure.
Firstly, I've visited ISRO Bangalore(A few years back). And I did see the exact things you mentioned. I did ask the guy(Not sure, if he was the PR guy) who took our class for the tour. His answer was, they were likely assembling some test equipment and not the real equipment that was going to space.
(Which unlikely given parent's NYT article:)
The modest budget did not allow for multiple iterations. So, instead of building many models (a qualification model, a flight model and a flight spare), as is the norm for American and European agencies, scientists built the final flight model right from the start.
It's unclear whether the room is a climate and particulate controlled cleanroom up to the standards required for inplanetary probes, but they may (hopefully) do sterilization through chemical and heat treatments - but that alone isn't enough for planetary protection.
Curiosity is a rover. Rovers require cleanrooms for assembly for the reasons that you just mentioned, since they land. I don't think this is an issue with orbiters. For example, one of the reasons failing orbiters are of concern is that contamination can be an issue if they crash into the surface. See Japanese orbiter Nozomi, for example: http://www.japantimes.co.jp/news/2003/11/29/national/experts...
Using the expert rule, I can't imagine Indian engineers not being concerned about contamination. It is such an obvious risk that it is probably one of the first things they'd look for. I mean, there is 50 years of precedent available to anyone working in this field.
Edit: Also, they may have done their work in non-cleanroom environments and post that, they may have sterilized the orbiter.
In the MRO image it's hard to see, but I'm pretty sure they are wearing thin white gloves (probably nitrile).
The ESA picture says its from a thermal and mass model, and the guy in question is hovering over a test fixture.
I can't say much about the ISRO video. I hope it's just press footage of something that isn't the actual flight unit. That would be pretty reasonable. Later in the video you can see the techs wearing gloves pulling the vehicle off a moment of inertia test. It's encouraging, but the fact that they're wearing hair nets while half the guys have giant, uncovered beards is not.
With Curiosity, NASA even went so far as to aim the initial trajectory to miss Mars. This was out of fear that the upper stage of the rocket, which did not have the same amount of contamination control, would collide with the planet.
MOM's orbit is fairly eccentric, so it's not likely to collide with Mars any time soon. I think we have a lot of time to study Mars before we worry about any potential contamination.
You are making vague assumptions and supporting with unscientific proof. Using phrases like "there is clear lack" or "clearly visible" etc. doesn't make your assumptions true. What's funny is that you are picking up random pictures from media and using that as evidence. There's
Some articles speculate about the rigorousness but can't confirm. Implying it doesn't exceed them doesn't equate to skipping the sterilization. Besides, it's carrying satellites from developed countries (France, Germany, Canada & Singapore), which I doubt would be complicit in creating an international controversy.
I don't think it is right to jump to conclusions based on those images. I have been to one of the clean rooms, where the satellite ASTROSAT was being created. We were in the outer most room. And for that too we had to wear these bunny suits covering all of our body, hair and skin. The actual satellite was in inner levels, where standards were higher and we were not allowed to go. We were not allowed to take any instrument inside of that room. So there were no photos. May be that is the reason for this perception, it is just bad PR. Based on my experience I do find that ISRO takes these standards very seriously.
I wrote that comment, however I'm not sure if the tour guide who showed us around was telling the truth- He might be lying, I don't know. You are right in the part that clean room practices are very important for missions like these.
This article highlights some points as to why the cost would be so less.
>>Some of them were puzzled by ISRO's style of working. They were just 18 months away from the launch date, and ISRO was only beginning to cut metal. One of the foreign partners had then asked ISRO managers: "Are you serious?"
If I'm not wrong NASA tests and validates the equipment they send into space for years. They also take a lot of time and observe very strict quality practices to ensure the equipment doesn't fail or malfunction in space. This leads to them frequently missing deadlines and over shooting budgets by large amounts.
Something that ISRO doesn't. Of course then they have a larger chance of running into failures. But then one wouldn't consider it a big loss to spend just $75 million and fail compared to similar projects in other countries that cost almost 7 times more.
>>tacitly acknowledged the value of the organisation's minimalist approach. "The told us after the launch," says M Annadurai, project manager of Chandrayaan, "that this was the Indian style of working".
India has a lot of talent and lot of young people wanting to succeed and prove their worth to the world. Given the mere population scale and level of desperateness to succeed. You will always run into ingenious people very often. Most of them come from small towns and lower middle class families who need a job at any cost, even if they have to work 16 hours a day, at whatever salary they are offered.
I was one such guy myself at one point of time. I've worked at a assembly line, call center, installed BSNL modems and now as a programmer. I know many of many friends from the villages who aspire to do anything thing can, with whatever means they have.
So I won't be surprised if they are succeeding in hiring some very brilliant people at the salaries they pay.
>>"Frugal engineering comes naturally to Indians," says National Research Professor RA Mashelkar, "which is why India delivers more than any other country per dollar of R&D investment." Mashelkar, along with management theorist CK Prahlad
I don't believe this is unique to Indians, but in general when you have fewer resources you tend to optimize you work to squeeze the most of whatever you have.
And then finally some budget and schedule discipline.
>>"Testing is expensive," says Radhakrishnan, "and we try to get the maximum information from each test." ISRO engineers worked round the clock, often in shifts, when the satellite was being made.
>>"ISRO is one of the few organisations in India that is driven by schedules," says Rajan.
So in short, work with passionate, hardworking people, save money by sticking to strict schedules, do not build anything unless you need, once you build test minimally but sufficient enough and quickly.
Not sure how it generates power? Pu238 is a very strong alpha emitter. Alpha particles (helium nuclei) are really big and charged, so they don't travel very far and deposit all their energy near where the decay occurs (as opposed to decay with e.g. neutrinos that essentially never interact and thus deposit no energy). The alpha decay carries a lot of energy so a chunk of Pu238 gets pretty hot. Couple it with a thermoelectric generator and you have an ideal power source for space applications.
Also, alpha particles have almost no penetrative power in human tissue so they're harmless as long as the source isn't inside of you. Pu238 is almost exclusively an alpha emitter, so it's completely safe to handle for extended periods, at least radiologically. It puts off a ton of heat and is chemically really toxic though. I've dealt with it in the lab before, it's relatively harmless as far as nuclear sources go. It's not suited for weapons either, so it isn't directly a proliferation concern, though producing it is because it is related to weapons grade production. You don't see it used very often mostly because it can only be made in a specially configured reactor, so it's not exactly common.
Thermoelectric generators are dead simple means of reliably generating a small amount of power for a very long time without moving parts. What you do is get a lump of radioactive material and stick a bunch of thermocouples around it. The lump of radioactivity stays hot because it's radioactive, and the thermocouples produce a very low efficiency amount of power out of the temperature difference.
Remember the used market is only workable in countries with enough previous purchase history over a long enough period, most developing economies don't reach that point for quite a few years longer than developed countries for a given technology.