PakledHostage

I thought it was better than Gravity

But we English speakers can't even agree amongst ourselves how to spell our words... There are English, Canadian, American, etc spellings for many words. Getting us to agree would be like trying to herd cats!

I thought I read that today was the last day that they could launch before the Moon's gravitational influence would have affected DSCOVR's delta-V budget beyond allowables? Presumably that means that the Moon does occasionally get close enough to the second stage's orbit to affect it significantly?

A 187 km high perigee should already be low enough to bring it down eventually. That's roughly 225 km lower than the ISS and even the ISS will come down eventually if they don't raise its orbit periodically. Edit: Sorry, I just noticed the 1.37 million km apogee... With that in mind, I suspect that the second stage will just end up in solar orbit. Maybe someone more knowledgeable can confirm?

DSCOVR spacecraft separation confirmed, according to NASA TV

Not necessarily. The animation you posted seems to show the current upper level winds rather than the typical upper level winds. You can clearly see the southerly dip in the jet stream that is currently situated over Colorado in both the analysis chart that I posted and your animation. The jet streams usually aren't that far south or that spread out.

The most recent NOAA surface analysis chart shows MSWH of 10-11 metres in that area. Mean significant wave height is the average height of the largest 33% of waves out there. That means that roughly 1 in 6 waves are bigger than that. Edit: They also seem to be running against the gulf stream so they'd be steep and dangerous... I don't envy the guys who are out there supporting the ASDS.

What's happening with the upper level winds? To my untrained eye, the 250 hPa analysis chart doesn't look much better today than it did yesterday?

I think it is worth pointing out (correct me if I am wrong, cicatrix and lajoswinkler) that the people expressing concern about online privacy have admitted elsewhere on this forum that they are from the former eastern bloc and former Yugoslavia. Maybe we shouldn't read their opinions so much as "paranoia" but as a warning. They are from cultures that have been down that road and it didn't end well. The phrase "you have nothing to fear if you have nothing to hide" is cringe inducing for a reason.

Fixed that for you.

I think the trouble many people have with Mandarin is how to pronounce the tones with enough accuracy to say the right thing. That was certainly my experience with the little bit of Mandarin that I've tried to speak, and I've heard the same from many others. I once tried to say hello to a friend's mother, (referring to her with the honorific title of "mother" even though she wasn't my mother) and I ended up saying "hello horse" instead of "hello mother". When they finished laughing, they told me that it is an easy mistake to make. They told me that there's even a nursery rhyme about those two words (plus two others) that sound very much the same, differing only subtlety by their tones. Maybe the point is that every language has its idiosyncrasies?

But there are other promising methods of storing energy. For example, flow batteries are seeing a lot of development work because the tanks and hardware can be housed inside wind turbines

I flew down to Florida to see STS-101 launch back in April of 2000. It didn't launch while I was there due to high winds. My regret isn't that I missed out on seeing that launch. My regret is that I didn't ever try again.

For anyone who's interested in still more details, here's a section of the Environment Canada upper level (250 hPa level) wind analysis chart from 1200 UTC today (Source: 250 hPa: Geopotential height, wind velocity):

Whiskey Tango Foxtrot?

Thanks. I watched it on my Chromecast. Not 4k but it still looked great on a big screen.

From the latest NASA press release about the upcoming DSCOVR launch on Tuesday (for what it is worth):

Here's a view of how Jupiter and the inner planets were oriented at the time of the transit, according to the Mobile Observatory app on my phone (time is GMT):

I was curious if the 1 second window wasn't actually a requirement of the barge landing test? The last Falcon launch (CRS-5 to the ISS) also had a 1 second launch window, IIRC. That's far more restrictive than the Shuttle for an ISS rendezvous mission.

Real life got in the way. I still like spaceflight and this community though... Hence my continued participation. On with the show.

Will I get flamed for admitting that I haven't played KSP in so long that I don't recognize the webcast music as being from KSP?

I am not going to argue with you, Iskierka, because I have disliked the "comic bookstore guy" tone of your posts for years, but I will make a few points: You can also see the stream lines travel upwards for some distance ahead of the airfoil. If I was to apply your own argument to the view looking forward from the airfoil test section, I could suggest that "there's no downwash, indeed there's upwash!". You can't look at them in isolation because the very images that you're referring show that there's upwash ahead of the wing as well as downwash behind it. Otherwise, you are correct that wind tunnels do affect the airflow around a test article. This is why you must apply correction factors to the measurements that you make in them. I don't understand why you are bringing reflex camber airfoils into this? Why is this relevant? Did I miss where someone brought it up? This is an oversimplified explanation. It doesn't account for why higher aspect ratios result in lower induced drag. How could such a strong vortex be created at the tip when the lift on a 3D wing (and the pressure differential between lower and upper surfaces) falls to zero at the tip? It also doesn't account for why the tip vortices don't form directly behind the wing tip. The initial distance between tip vortices is typically about 85% of the wing span. An airfoil (and indeed a wing) generates circulation about itself when moving through a viscous fluid like air through a combination of the shear forces that occur in the fluid at the sharp trailing edge (ref. the Kutta condition that I mentioned in one of my earlier posts) and conservation of angular momentum. Conservation of angular momentum requires that net circulation in the fluid must be conserved. Where a wing creates circulation, equal and opposite circulation must be created elsewhere. That circulation is fundamental to the production of lift because it results in a pressure field about the wing being created as a result of conservation of momentum and conservation of energy. Vortices also can't just begin or end in a fluid. A wing will shed a small part of its bound vortex with every change in lift along its span. In a 3D flow, the lift on a wing is not uniformly distributed from root to tip; the lift per unit span decreases all the way out to the tip. In a viscous flow, all of these minute vortices roll up to form a trailing vortex that is located inboard of the tips. The sum of these shed vortices results in a net downwash behind the wing in addition to the aforementioned trailing vortices. If readers of this thread have any doubts about what I've written, they can do their own experiment to learn more about circulation about a lifting surface in a viscous fluid. All it takes is some chicken broth (or similar fluid with low viscosity oil on the surface to aid flow visualization). 1. Take a knife and insert the blade into the broth at a small angle of attack 2. Suddenly accelerate the knife through the broth, maintaining the small angle of attack. Note that a little "whirlpool" forms where the knife started moving from. This is a starting vortex. It is related to the natural occurrence of the kutta condition on the knife's trailing edge in a viscous fluid due to conservation of angular momentum and shear forces in the viscous fluid at the knife's trailing edge. 3. Let the broth settle down for a few seconds and then move the knife smoothly through the broth at an angle of attack again. This time stop it suddenly. Note that a little whirlpool is shed by the knife and continues to move towards the edge of the bowl at the speed that you were moving the knife? This is the bound vortex/lifting vortex being shed by the knife when it stops producing lift. 4. The bound vortex changes in intensity with every change in lift. Increasing the angle of attack of the knife will also increase circulation about the knife. If you do it carefully and suddenly enough, you will be able to see a second starting vortex generated in the broth at the location where you increased the knife's angle of attack. This starting vortex conserves the angular momentum of the new opposite circulation that has been created about the knife. 5. And while you can't see it in the broth, there is a vortex under the surface that connects the starting vortex and the bound vortex. This is the same vortex that you see trailing from the wings of an airplane. In a real fluid, the trailing vortex will break up into little eddies and dissipate, but overall, angular momentum is still conserved.

Please give me 12-18 hours. I don't have time to respond right now, but I will get back to you (unless someone else wants to take it on before I get to it).

And fuel. And paperwork... but I digress. Lift has a lot to do with viscosity. The kutta condition is imposed naturally when viscous fluids (i.e. air) flow over an object with a sharp trailing edge. All airfoils have sharp trailing edges, regardless of whether they are symmetrical, cambered or are composed of a single membrane that has no relevant thickness (like a sail). The Kutta condition requires there to be circulation about the airfoil that causes air to flow faster over one surface of the airfoil than it does over the other. That circulation manifests itself in the form of tip vortices trailing back from the tips of a finite wing. The tip vortices, in turn, result in downwash. An infinite aspect ratio wing doesn't have downwash because it doesn't have tip vortices. Induced drag is a function of downwash strength, which is why induced drag is greatest at high angles of attack and large flap deflections. High angles of attack and large flap deflections both generate higher circulation (and stronger tip vortices) than a clean wing experiences at low angles of attack.

OK. I assumed that Φ was to be the latitude of the observer at V. Just be sure that you restrict yourself to the 2D case if you're going to solve it using an SSA triangle.