If we look at jet aircraft, wear depends on the airframe and the engines, and the airframe seems to be the number of pressurize/depressurize cycles as well as the running hours. Engines get swapped out routinely but when the airframe has enough stress it's time to retire the aircraft lest it suffer catastrophic failure. Rockets are different in scale (much greater stresses) but we can expect the failure points due to age to be those two, with the addition of one main rocket-specific failure point: cryogenic tanks.
How long each will be reliable can be established using ground-based environmental testing. Nobody has the numbers for Falcon 9R yet.
Weight vs. reusable life will become a design decision in rocket design.
An English major is NOT getting into a STEM Ph.D. program, no matter what.
Even if they were, job prospects are worse for STEM Ph.D. holders than for MS/BS holders—there are far fewer jobs that require Ph.D. level qualifications outside of the professoriate and academics, and for Ph.D. holders in particular, employers are absolutely loathe to hire overqualified people.
Inside the professoriate and academics, the job market is historically bad right now. It's not "get a Ph.D., then become a lab head or professor," it's "get a Ph.D., then do a postdoc, then do another postdoc, then do another postdoc, then do another postdoc, really do at least 6-7 postdocs, moving around the world every year the entire time, and at the end of all of that if you've managed to stay employed at poverty wages using highly competitive postdocs that you may not even get, while not flying apart at the emotional seams, you may finally be competitive enough to be amongst the minority of 40-year-old Ph.D. holders that gets a lab or a tenure-track position, at which point the fun REALLY begins as you are forced onto the grantwriting treadmill and feel little job security, since universities increasingly require junior faculty to 'pay their own way' with external grants or be budgeted out."
And that's INSIDE STEM, which this person is almost certainly likely to be uncompetitive for as a B.A. holder trying to get into graduate programs.
Much more likely is that with great grades and GRE scores they'll be admitted to a humanities or social sciences Ph.D. program, with many of the same problems but with CATASTROPHICALLY worse job prospects due to the accelerating collapse of humanities budgets and support on most campuses.
Ph.D. is absolutely not the way to go unless you are independently wealthy and are looking for a way to "contribute to the world" since you don't actually have to draw a salary.
For anyone with student loans, it's a disastrous decision right now, and I wouldn't recommend it.
I say this as someone with a Ph.D. who is on a faculty and routinely is approached by starry-eyed top students looking to "make the world a better place" and "do research." Given the competition out there right now, only the superstars should even attempt it, and then only if they're not strapped for cash. Hint: If you don't know whether or not you're a superstar, you're not.
I think in a decade I've strongly recommended that someone enter a Ph.D. program once, and greeted the suggestion favorably maybe three times total, out of thousands of students, many of them with the classic "4.0 GPA" and tons of "books smarts."
In short, I disagree strongly with the suggestion. Unless you absolutely know that you're competitive already on the academic market, DO NOT GO. Don't listen to the marketing from the schools; it's designed to drive (a) your enrollment and tuition, and/or (b) your cheap labor as a teaching assistant/research assistant forever once you're in the program. It's a win for the institution, not for you.
The easiest sanity checks: Do you know exactly what your dissertation will be about and what you'll need to do, in broad strokes to conduct your research, as well as what resources you'll need? Do you already have personal contact with faculty on a well-matched campus in a well-matched department that are championing you and that want to bring you in as one of their own students/assistants?
If you answers to either one of these questions is "no," then while you may be offered a position somewhere, you will be on the losing end of the deal and would be naive to take it.
Link to Original Source
From the look of things, this is already happening:
Like others I found the headline confusing. I read it as "Researchers are predicting the use of Wikipedia as a vector for the spread of disease". This may mean that:
- Disinformation and ignorance are diseases.
- Memes and computer viruses are diseases.
- Wilipedia contains information that leads to depression.
- Instructions on Wikipedia lead to substance abuse.
- This is getting entertaining, fill in your own reason here.
One of the definitions I found was:
One who makes great sacrifices or suffers much in order to further a belief, cause, or principle.
I am sure that fits. While SpaceShip II is mainly intended for a non-exploration purpose, the program has resulted in some significant advances in rocketry and White Knight II has significant non-tourism use. These pilots have been involved in other space efforts, I remember the one who was injured from the Rotary Rocket test flights. There are lots of safer ways for these folks to make as much money as a test pilot is paid. They do what they do to advance our progress in aeronautics and space.
Martyrs? Who killed them for their beliefs?
Go away, troll. They certainly died while pursuing something intensely important that they were willing to risk their lives for. The fact that you weren't around to pull the trigger makes them no less martyrs.
Anyway, I have better uses of my time than to waste another minute with you.
We knew what was going on when you ran your anti-IBM campaign, sometimes even positioning yourself as arguing on behalf of our community. It was a way to lend credence to IBM and MS arguments during the SCO issue. To state otherwise is deceptive, perhaps even self-deceptive.
Florian, you would not be devoting all of this text to explaining yourself if you didn't feel the need to paint your actions in a positive light. That comes from guilt, whether you admit it to yourself or not.
Go write your app, and if you actually get to make any money with it you can give thanks, because it will happen despite what you worked for previously. Keep a low profile otherwise because your credibility is well and truly blown and you can only make things worse. And maybe someday you can really move past this part of your life. But I am not holding out much hope.
So, I see this as rationalization.
The fact is, you took a leadership position, and later turned your coat for reasons that perhaps made sense to you. But they don't really make sense to anyone else. So, yes, everyone who supported you then is going to feel burned.
You also made yourself a paid voice that was often hostile to Free Software, all the way back to the SCO issue. Anyone could have told you that was bound to be a losing side and you would be forever tarred with their brush.
So nobody is going to believe you had any reason but cash, whatever rationalization you cook up after the fact. So, the bottom line is that you joined a list of people who we're never going to be able to trust or put the slightest amount of credibility in.
And ultimately it was for nothing. I've consistently tried to take the high road and it's led to a pretty good income, I would hazard a guess better than yours, not just being able to feel good about myself.
Meh, it's easy to find people with skill. With values, OTOH...
You have a point.