PakledHostage

I was going to try tomorrow morning. My weather window has moved up from Sunday morning. I hadn't actually considered image stacking as an option, but I did some practice image stacking last night after Lexif mentioned it. I didn't have much success; I get better images with a fast prime lens and a high ISO. I will try both methods tomorrow morning. It looks like it is brightening nicely, but I may not get another chance to see it until after perihelion because the local long range weather forecast doesn't look promising for astronomy. Articles that I've read (such as this one in "Nature") indicate that ISON is large enough that it won't be vaporized and predict that ISON will survive perihelion. Below is the most recent light curve from the Comet ISON Observing Campaign group:

"Rendezvous in reverse" as a means of evenly spacing out satellites around an orbit. Basically, you start with a launcher that has multiple satellites aboard and place it into a transfer orbit that both intercepts with and has a suitable orbital resonance with your final working orbit. You then release satellites at the point where the orbits intercept and boost them into the final working orbit while the launcher spacecraft continues to orbit in the transfer orbit. Over the course of several orbits, you can release all of your satellites in an evenly spaced pattern and in the same orbital plane. The process is a bit difficult to explain in writing, but I made a video for my Figaro GNSS mod's thread that shows how I used the method to place my GNSS satellites in orbit:

It may be a bit early but you never know. You might be able to capture it with a decent camera. If you do manage to photograph it tomorrow, would you be willing to post your picture on these forums? I'd be interested to know what settings you used. I have a potential weather window on Sunday morning. If it still looks promising on Saturday, I may even try to borrow a friend's Canon 6D. It is a good low light camera and will give me my best chance of getting a picture.

Which is also a good way to save delta-V. Stochasty used the method very effectively in the Minimum Delta-V to the Mun challenge from last winter (although nobody used the term "harenodynamics" to describe the landing). Sadly that thread was lost along with so many good threads when the forum database crashed. I was able to find his video, though:

The Comet Ison Observing Campaign group has a nice website detailing scientific efforts around the world to observe Ison. Their site includes a light curve that is updated every two or three days. The plot below is the most recent update from November 11th:

According to a BBC article from about 45 minutes ago, initial estimates are that any debris came down along a line stretching through eastern Asia and the western Pacific to Antarctica. While Texas is indeed big, none of those places are in Texas.

The point is the same because the planet or moon is rotating about its axis in a stable equilibrium. The stable equilibrium is driven by the dynamics of the system, in so far as an external torque exists that constantly restores the rotational speed of the orbiting body to a stable resonant frequency after any perturbation. In the absence of such a stabilizing torque, there is no stable equilibrium and no reason to expect the orbiting object to rotate about its axis once per orbit, three times for every two orbits, or at any other rotational rate.

Hello? Oh, hello grade 8, I thought we'd gone our separate ways?... What's that, I was wrong? Well I stand corrected. Sorry. Nice talking to you. Have a good day... [hangs up phone] p.s. the point is the same whether it is tidally locked in a 1:1 resonance, or in some other resonance.

Mercury, as is true of our moon and likely many of the known exoplanets, is tidally locked. Please see the above discussion about tidal locking as applied to spacecraft.

Further to m4v's post, I'd like to add that satellites are only visible when they are above the horizon. Like with real GNSS systems, the signal is line of sight. Edit: Reposting a .gif from the Q&A section on the first page of this thread. It shows how the number of visible satellites in the real world GPS system changes with time:

Something about your entire post rubs me the wrong way... I discussed this thread with my wife last night. I wanted her opinion on it because she lived in rural India for several years. It is because of that conversation that I previously said that I don't want to argue the point either way. I do feel the need to point out, however, that your post and many others in this thread are full of cultural biases. India is a complex society of over a billion people. It has often been said that it is really two countries within a country. People in rural parts of the country may be "poor" by western standards, but that doesn't mean they are universally unhappy or don't have any opportunities to better themselves. You can't stereotype the entire country based solely on media images of the urban poor, or legacy colonial prejudice. After all, even a country as rich as the United States has its own share of desperately poor people in its urban centres. Urban poverty is a separate problem that needs its own attention, independent of the pursuit of science and technology.

I don't want to argue this point either way, but I do want to point out that Wikipedia's list of countries by foreign aid received shows that India received $1.4 billion in foreign aid in 2007 and $2.1 billion in 2008. Compare that to Israel (yes, Israel) that received $2.5 billion in 2007 and $2.4 billion in 2008.

What's that they say? Never let the facts get in the way of a good story? To add to what MrShifty said, re-entry heating is really just all about conservation of energy. A spacecraft in LEO has an immense amount of potential and kinetic energy that must be dissipated during re-entry. The majority of that energy is kinetic energy. An object orbiting the Earth at 400 km has roughly 4 MJ/kg of potential energy and a whopping 30 MJ/kg of kinetic energy relative to an object on the surface. This is why SpaceShipOne can re-enter without heatshields. It has very little, if any, kinetic energy at the top of its ballistic arc. It needs to dissipate less than 2 MJ/kg, whereas the space shuttle needs to dissipate upwards of 34 MJ/kg. An object returning from the Moon has to dissipate close to twice as much energy as an object in LEO, and the Stardust probe's sample return capsule entered the Earth's atmosphere with over 80 MJ/kg! An aggressive aerobraking pass will cause significant heating and will require a heat shield. The most aggressive form of aerobraking is aerocapture. In the case of aggressive aerobraking, heat dissipation is a further problem because there's no convection in space to cool the shield between aerobraking passes. Radiation is the only cooling mechanism and it isn't as effective as convection. Ablative heat shields designed for multi-pass aerobraking/aerocapture must also tolerate repeated exposure to elevated temperatures without failing or burning through. The multi-pass aerobraking followed by aerocapture process described in the OP works in KSP because the current re-entry heat model doesn't take into account ablation of heat shields, and the unshielded spacecraft components are more tolerant of high temperatures than real life spacecraft.

What they are doing is a series of small perigee kicks to add orbital energy to the spacecraft, in preparation for the final ejection burn that will send it on its way to Mars in December. The perigee kicks take advantage of the Oberth effect to increase the efficiency of the burns. NASA's LADEE probe used the same procedure to reach the moon. I have actually been thinking of hosting a new efficiency challenge, along the lines of my earlier "Minimum delta-V to the Mun" challenge that was lost when the forum database was corrupted last spring. During the old challenge, people tried techniques such as perigee kicks with some success. Edit: Ninja'd by Kryten

I agree. I am always impressed by the camera work. It is not as easy as they make it look. Thanks for sharing this video, Mr Shifty.

Through experimentation. A lot of it is documented in this thread: Mini challenge: Max altitude with this supplied spacecraft. Indeed, that thread was arguably the genesis of MechJeb.

If by that you mean the one below, then I agree wholeheartedly. Let's hurl Ron Ford at it...

Here's my entry. A roughly circular orbit at 115.4 km.

Well add me to the list of well wishers. While the launch will be a day late, it will be one heck of a way to cap off this year's Diwali fireworks! Good luck with the mission and à ¤¦à ¤¿à ¤µà ¤¾à ¤²à ¥€ à ¤•à ¥€ à ¤¶à ¥Âà ¤­à ¤•à ¤¾à ¤®à ¤¨à ¤¾à ¤Âà ¤‚ to everyone at the ISRO.

Did anyone on the east coast of North America get up early this morning to catch the partial? What about you, WooDzor? Did you manage to get any photos from wherever it is that you are located?

And what side is "my side", exactly? Please show me where I wrote that I was against nuclear energy outright? All I ever advocated was caution in expanding our reliance on it because there are real risks associated with using it. Being cautious doesn't mean don't do it. I am a rock climber. I am also an engineer in a safety critical industry. I am cautious when I go climbing and when I sign an authorization, yet I still do both on a regular basis. Although I have been following this thread for the past few days, I have been trying to stay out of it because it is full of ideologically motivated personal attacks. Clearly I should have exercised more self control...

Never underestimate the ability of people to come up with new and creative ways to have accidents. Chernobyl and Fukushima may be unlikely to happen again, but that doesn't mean that there won't be other accidents... Just like nuclear power plants, transport category aircraft are operated and maintained by professionals, yet accidents still happen. It is often said that the aviation regulations are written in blood; the regulations are updated every time somebody invents a new way to have an accident. Take, for example, the shape of control knobs in cockpits. FAR 25.781 specifies the shape of each control. The shapes help pilots identify the correct control in low visibility and during lapses in concentration. Some might have claimed that there'd never be another accident due to a pilot activating the wrong control. Then along came the crew of China Eastern Airlines Flight 583: One of the flight crew accidentally deployed the leading edge slats when he dropped his clipboard. Two people died and 60 people ended up in hospital as a result of injuries sustained during the resulting upset. The MD-11's flap lever was originally designed to meet the requirements of FAR 25.781 but it wasn't enough. It was redesigned following the China Eastern Airlines accident. Thanks for helping me make my earlier point.

What's promising about it? It reads like a religious discussion. Just about everyone who's expressed any concern about nuclear energy in this thread has been shot down as being stupid, irrational, a hippie or some combination thereof... Now we can add troll to the mix. Risk management involves more than just simple statistics, and complex issues like the risks associated with nuclear or any other form of energy need intelligent discussion. There is almost certainly room for both sides of the argument to learn something, but this thread isn't turning out to be a forum where that can happen.

I was the Ralph Wiggums of my neighborhood. I was late in learning to read and a lot of the other kids and even some of the teachers thought I was dumb. I am not sure what changed for me, but when I finally did learn to read, I read everything I could get my hands on. I remember regularly skipping class in grade 5 to go read in the library, and I'd sign out encyclopedia volumes to read on the school bus. I think I was just bored with school but I was fortunate to discover that I could teach myself interesting things. Through it all, I always gravitated towards math and science subjects. Maybe I'm just hard wired for it?

Agreed. Below is a chart showing winds right now at the 250 HPa level over our own planet. The chart shows the location of the jet stream. The wind arrow over SW Kansas is indicating a wind speed of 140 knots (about 260 km/hr or 72 m/s). The chart shows that United Airlines flight 656 reported similar wind conditions over the Wyoming/Nebraska border. Airliners are routinely flight planned to take advantage of winds like this to save fuel and shorten flight times when flying west to east. Most times, the passengers won't even notice.