PakledHostage

I 100% agree. I would love to see another mission to Venus funded and successfully executed. Particularly if it was a multi month long study of Venus' climate, atmosphere, geophysics and remote sensing of its surface using a balloon probe. And I agree with you, AngelLestat, that such data may be vitally important to helping us understand our own planet's climate. The point of contention for me is whether or not we need to send people. We can do a lot of sophisticated data gathering and picture taking without physically being there.

It doesn't matter. The physics are the same whether it is a fighter jet or a transport aircraft. Fighter jets may well sometimes fly by hanging on the engine at 90 degrees angle of attack, but they aren't doing it at supersonic speeds. And while it is true that high wing loading (i.e. high lift per unit area) mitigates the effects of a sharp edged gust, my point still stands. Sharp edged gusts of the magnitudes you are describing can not be hand-waved away. Maybe it is as a result of a language barrier, but you seem to have an overly simplified understanding of aerodynamics. I am only trying to help you fix that.

It doesn't work like that. Lift is a function of airspeed and angle of attack. At high speed, you may only need one degree of AOA to maintain level flight. If you suddenly increased AOA by a factor of ten (to 10 degrees), you'd increase the lift produced by the wings by roughly a factor of 10 as well. This is why airliners slow down when they encounter bad turbulence . They could suffer catastrophic structural failure if they flew too fast through severe turbulence because they aren't built to handle the loads that can be generated at high speed. They could literally pull themselves apart. If you go slow enough however, the wings and tail can't produce enough lift to bend/break themselves or other parts of the structure because they will stall before forces get high enough.

This all sounds fascinating but, given the time frames involved before any of this is even remotely possible, we're really talking about science fiction. And isn't it reasonable to speculate that, in such a world, robot technology will also have advanced to the point that they would also be far more autonomous? As with current space exploration, we need to ask ourselves how much of this really requires a human presence?

I, along with several others, told our own fascinating stories in this thread.

I'm thinking about buying a tracking mount for my camera. I've used Deep Sky Stacker a fair bit to stack frames to yield a longer effective exposure, but I am limited by the quality of the images that I stack. Garbage in, garbage out, as they say. It doesn't take a very long exposure before you get star trails when you're using a long lens. The tracking mount that I am considering getting is the Sky Watcher Star Adventurer. It seems to get good reviews online and it is in the $350-$500 range depending on accessories. And it can be used with a small telescope (up to 5kg) as well as a camera. Anyone here have any other suggestions? Or maybe someone here even has a Star Adventurer? I know that there are better tracking mounts (i.e. multi-axis mounts or "go to" mounts) out there, but I don't want to spend thousands of dollars. I'm looking for the best value mount rather than "bells and whistles". Maybe there's even a cheaper option?

Jeremy Clarkson did a documentary about its final action, for which five Victoria Crosses were awarded:

What are you trying to say? That the Vasa wasn't historically significant? ... [Pause for response] ... Oh ...

I think this is a good guess. You're probably using the geometric angle of attack of the tail fins to impart a restoring moment, but in reality the fin's angle of attack would vary with the rotational speed and the angular displacement (i.e. aerodynamic angle of attack != geometric angle of attack). You might also want to double check how you've formulated your equations to make sure you're not aggravating the problem due to a loss of precision. A good read is "Lies My Computer and Calculator Told Me".

I'd have to go with the Vasa. Sweden's anti-hero of warships... It very publicly sank after sailing only 1300 metres from where it was launched. It makes a nice museum piece today.

This introduces a new elephant into the room: Ceres. If the motivation for building a base is resource extraction, why not just ignore Venus and Mars and focus on Ceres? As has already been pointed out, the Moon is probably the most suitable candidate for our first permanent outpost on another celestial body, but maybe the next logical destination is Ceres after we've cut our teeth there? It has low gravity and at most a tenuous atmosphere, making it easy to launch from and land upon. It also likely has a 100 km thick mantle of water ice totaling over 200 million cubic kilometers of water. Its location in the asteroid belt and ready access to water for making rocket fuel would seem to make it a far better candidate as a base for mining asteroids than Mars or Venus. A downside is the low gravity.

The requirement to comply with ADs issued by the country of manufacture of an aeronautical product is usually written into the local country's airworthiness regulations in accordance with multilateral agreements between participating nations. Some countries will also issue their own ADs mandating accomplishment of another country's ADs. Still other countries (typically developing nations) will require their operators to follow the rules of a country with a more developed regulatory framework. In extreme cases where the home nation just doesn't give a hoot, there's always the option of preventing an aircraft from using the airspace outside of its home territory. IIRC, there was a case recently where a middle eastern carrier was either banned or threatened with being banned from UK airspace because its pilots didn't speak the international language of aviation - English - well enough and they were dangerously misunderstanding ATC instructions.

The Turkish Airlines tragedy is a lesson in human factors more than a damnation of the aviation safety regulatory process. The cargo door latch mechanism on the DC-10 uses an over centre cam to hold the latch closed. As an added level of redundancy, there is a pin that inserts into the latch assembly after the latch cam is rotated over centre. If the pin isn't aligned with the hole in the latch (i.e. when the latch isn't over centre), then you're not supposed to be able to fully stow the latch lever, which should indicate to the door operator that something isn't right. After the Detroit accident, the FAA issued airworthiness directive 74-08-04 to mandate inspections and accomplishment of McDonnell-Douglas Service Bulletin 52-27. Transport category aircraft are so complex that airworthiness directives are issued against all aircraft types several times a year. This AD was unusual, however, in that it had to be accomplished prior to further flight. ADs issued by the regulatory authority of the country of manufacture of an aeronautical product are mandatory for every operator, so Turkish Airlines was also required to comply with AD 74-08-04. The tragedy is that, while they did comply, they made a maintenance error in the accomplishment. The service bulletin adds an inspection window to the cargo door so that operators can see that the pin is engaged and replaces the original pin with a longer pin to make it harder to force the door latch closed if the pin isn't engaged. Somehow Turkish Airlines' mechanics misunderstood the instructions and shortened the pin rather than installed a longer one. This made it possible for the door latch lever to be closed without any unusual amount of force being applied, even though the latch cams weren't over centre. Again, the secondary latch pin only engages in the hole when the latch cam is over centre. The longer pin installed per the service bulletin should buckle if the operator forces the latch closed, which would be visible in the inspection window, but a shorter pin wouldn't buckle or require an unusual amount of force to be applied to stow the door latch lever. And it was treated seriously in the example you gave, as I pointed out above. Indeed, there were several more ADs that were issued as a result of the Turkish Airlines accident. At least one of them (AD 75-15-05) affected all widebody aircraft, including Boeing, Airbus, Lockheed and Douglas aircraft. It was determined that all widebody aircraft did not have sufficient blowout panels between the passenger cabin and cargo holds to prevent the pressure differential from causing the cabin floor to collapse in the event of a pressure differential across it.

You can choose to interpret the statistics however you like but you're going to need to reference an ICAO or a regulatory body's definition of "safety" if you're going to be so emphatic. Also, by definition, if an aviation occurrence involves fatalities, it is an accident not an incident. The term "Accident" and "Incident" have very specific meanings in aviation. Ref: ICAO Convention on International Civil Aviation Annex 13, Chapter 1 - Definitions (page 10 of the .pdf document).

IIRC, that was the justification for retiring the SR-71fleet back in the early '90s.

On a lighter note, it seems that French president François Hollande has found Philae, in a manner of speaking.

I had to look up railfanning too. And while I can't say I am much of a train spotter, I have been accused of being a plane spotter. Friends bug me that I can tell what time it is based off which flights are going overhead. It isn't like it is a hard thing to do, though. When a distinctive airline only flies in once or twice a day, it doesn't take a rocket scientist to make an educated guess about the time or to know where the flight is coming from / going to.

I got two books: "Curiosity" by Rod Pyle and "You are Here" by Chris Hadfield. Oh, and a lump of coal...

This seems to be the appropriate place to leave this. Merry Christmas everyone!

Well then I guess we'll have to agree to disagree. You haven't made a convincing argument. If anything, you've succeeded in supporting my point. The joint ESA/NASA missions to Jupiter's moons and Saturn/Titan that I gave as examples were conceived and later cancelled during the ISS era. The ISS era is one of the two times that you highlight where there was an increase in funding for NASA. If increased funding for manned missions should also result in increased funding for robotic missions then we should have seen the effect during the period of increased funding for the ISS. And just to be clear, I am all for manned space exploration. However when significant mission opportunities are being cancelled due to lack of funding while the international community continues to spend tens of billions of dollars each year on manned missions to LEO, then I would argue we have to re-consider our priorities.

Yes, in the spirit of the hundredth anniversary of the Christmas Truce, Merry Christmas, Frohe Weihnachten and Joyeux Noël to both of you!

Who here is saying we shouldn't or aren't "building Rome"? Advocating for a practical approach to increasing our capabilities in and knowledge about space is not the same thing as advocating that we do nothing. There are missions that robots can do better than people, there are missions that people can do better than robots and there are missions where using robots is currently our only alternative to doing nothing.

You're misrepresenting arguments again. I am pretty confident that pretty much everyone on this forum is a fan of space exploration. To use your analogy, everyone here likes to go to the gym. But there's a difference between building fitness in a healthy manner that is supported by knowledge of human physiology, and pumping up on 'roids. Rome wasn't built in a day.

I used the phrase "hundreds of billions or trillions". Used that way in colloquial English, it implies an upper limit. Also, one trillion is less than an order of magnitude greater than the number you gave for the cost of the ISS. Unlike some other European languages, milliard and billiard do not come between million, billion and trillion in English. But please, can you use your "greater common sense in space economics" to answer my earlier questions?

Let me just make sure that I understand you clearly: Spending hundreds of billions or trillions of dollars to send people to Venus to spend a month performing atmospheric measurements and climate studies from a balloon is rational while believing that spending all that money on a manned mission will divert funding from smaller unmanned projects is irrational? I have already provided examples of joint ESA/NASA robotic missions that have been cancelled or mothballed because there's a lack of funding. Maybe you can explain how you envision those programs being funded as a by-product of your Venus mission? And maybe you can explain what people floating around in a balloon in Venus' atmosphere can do that a robotic Venus mission couldn't?