Satellites in geostationary orbit are in permanent sunlight for the majority of the year except for "eclipse seasons" (vernal and autumnal equinoxes, lasting a total of about a month each) during which satellites can see up to 70 minutes of eclipse per day. This is caused by the Earth's equatorial plane being inclined to the ecliptic.
First: The Earth's relationship with the Moon is such that their barycentre is inside the Earth, about 1700 km below the surface.
Second: L4 and L5 are potential minima, meaning the gravitational potential field increases as you move away from these points. Although the term "well" is misleading, it is certainly more applicable than "hill". It is this increasing potential that leads to the Lyapunov stability of L4 and L5 in the restricted three-body problem. The definition of this kind of stability is that if you are perturbed from equilibrium some small delta less than epsilon, then you will stay within that epsilon band.
Third: The Earth-Sun Lagrange points currently occupied by satellites are L1 and L2, for perpetual sunlight and perpetual shadow respectively. L1, L2, and L3 are all unstable, hence the necessity for station-keeping of these satellites. As far as I am aware, there are no satellites currently occupying L4 or L5.
Fourth: Large Impact Theory is just that, a theory. One of the objectives of this mission is to determine if there are small asteroids at L4 and/or L5, which could either lend support to or detract support from this theory. Regardless of whether this event happened or not, the L4 and L5 points still exist for any restricted three-body problem. Case in point: Jupiter-Sun L4 and L5 are filled with the Trojan asteroids.
From the Wikipedia article(s) on the SSMEs and RS-68 (the former being the Space Shuttle main engines, and the latter being designed for the Delta IV Heavy launch vehicle, and later being snapped up for the Ares V):
The [SSMEs] are removed after every flight and taken to the Space Shuttle Main Engine Processing Facility (SSMEPF) for inspection and replacement of any necessary components.
A leading goal of the RS-68 program was to produce a simple engine that would be cost-effective when jettisoned after a single launch. To achieve this, the RS-68 has 80% fewer parts than the multi-launch Space Shuttle main engine (SSME). Simplicity came at the cost of lower thrust-efficiency versus the SSME: the RS-68's thrust-to-weight ratio is significantly lower and the RS-68's specific impulse is 10% lower. The benefit of the RS-68 is its reduced construction cost: To build an RS-68 for the Boeing Delta IV program costs about $14 million, compared to $50 million for the SSME. While the SSME's higher costs were designed to be spread across multiple launches, the larger, less-costly, more powerful (50% more thrust) RS-68 was a more cost-effective engine for an expendable launch vehicle.
The regenerative nozzle of the SSME may have an advantage over the ablative RS-68 by providing a more resistant nozzle in the extreme environment of the core stage cluster.
Of course all of this is moot because I failed to recognize that we were talking about SRBs as opposed to SSMEs.
The shuttle concept in an of itself is not a terrible idea, however it got horribly warped by the Air Force's unrelenting requirements (i.e. payload bay size, etc.) and morphed into something horrendously inefficient.
There are certain parts of rockets that lend themselves much more to re-use than others. In this case, I believe the intent for Ares rockets is to replace the nozzle each flight -- they decided it was cheaper to build consumable thruster nozzles for each flight than to re-process the expensive, intricate cooling designs for keeping a nozzle in good enough shape to use again.
The atmosphere remains a fairly significant factor in satellite design up to altitudes of about 1000km (depending on where you are in the solar cycle; as Sun activity increases, the atmosphere expands). However, your premise remains.. 250km is a VLEO (Very Low Earth Orbit).
There is no "sunny side" of the Moon, nor is there a "dark side"; it has days and nights just like Earth does. The lunar day (or synodic period) is about 29.5 days (..Earth days, that is) long.
No kidding.. this is like the record industry releasing shitty music without DRM and pointing to its low sales to show that people don't want to buy DRM-free music.
There's also a big difference between making a rocket which can reach escape velocity and making a rocket that can just put something in orbit. All an orbit really is is a constant state of free-fall.
And maybe that they also know how to build and launch an entire satellite, including the radio communications sub-system. Currently operating on-orbit:
So it's a good thing that in areas like the maths, sciences, and engineering, LaTeX will reduce the amount of time you spend updating and fixing student handouts.
I'm running Ubuntu Intrepid on a Lenovo T61. It suspends to disk (or RAM) and resumes very nicely as well. However, it didn't always. Up until recently, there was a bug in the iwl4965 driver that prevented re-loading of the kernel module after suspend (or any unloading).
All of the manned missions to the Moon took place in a relatively small area on the near-side. As far as I can tell from the press spiel in the link, M3's mission is to survey the entire surface of the Moon.
At present there is very little data of any sort regarding the far-side of the Moon. Information on the magnetic and gravitational fields is of particular interest because of its importance for orbital prediction, determination, and manipulation.
The new AMC theatre at Yonge and Dundas in Toronto is quad-HD, so 3840x2160 resolution. It looks a little sharper than the traditional projector systems we've become used to, but there are huge advantages in terms of not having to switch reels, not having random black and white spots, etc.; I'm thoroughly enjoying it!
Looks related to this research done in the late seventies.
C.T. Russell and R.C. Elphic. ISEE observations of flux transfer events at the dayside mangetopause. Geophyiscal Research Letters, vol. 6, pp.33-36, 1979.
that classify as "internal combustion", and jet engines (in the general case, e.g. pump-jets on SeaDoos don't count) are one of those types. And before you go off the handle, rockets are actually a sub-class of jet engine.
Slashdot Mirror
Satellites in geostationary orbit are in permanent sunlight for the majority of the year except for "eclipse seasons" (vernal and autumnal equinoxes, lasting a total of about a month each) during which satellites can see up to 70 minutes of eclipse per day. This is caused by the Earth's equatorial plane being inclined to the ecliptic.
-Aikon
Roses are red
Violets are blue.
All of my base
Are belong to you.
First: The Earth's relationship with the Moon is such that their barycentre is inside the Earth, about 1700 km below the surface.
Second: L4 and L5 are potential minima, meaning the gravitational potential field increases as you move away from these points. Although the term "well" is misleading, it is certainly more applicable than "hill". It is this increasing potential that leads to the Lyapunov stability of L4 and L5 in the restricted three-body problem. The definition of this kind of stability is that if you are perturbed from equilibrium some small delta less than epsilon, then you will stay within that epsilon band.
Third: The Earth-Sun Lagrange points currently occupied by satellites are L1 and L2, for perpetual sunlight and perpetual shadow respectively. L1, L2, and L3 are all unstable, hence the necessity for station-keeping of these satellites. As far as I am aware, there are no satellites currently occupying L4 or L5.
Fourth: Large Impact Theory is just that, a theory. One of the objectives of this mission is to determine if there are small asteroids at L4 and/or L5, which could either lend support to or detract support from this theory. Regardless of whether this event happened or not, the L4 and L5 points still exist for any restricted three-body problem. Case in point: Jupiter-Sun L4 and L5 are filled with the Trojan asteroids.
-Aikon
Off-topic, but I always loved that idea and have used The Songs of a Distant Earth as an example of how to set up an off-world colony.
Aikon-
From http://www.nasaspaceflight.com/2008/12/ssme-ares-v-undergoes-evaluation-potential-switch/:
Of course all of this is moot because I failed to recognize that we were talking about SRBs as opposed to SSMEs.
The shuttle concept in an of itself is not a terrible idea, however it got horribly warped by the Air Force's unrelenting requirements (i.e. payload bay size, etc.) and morphed into something horrendously inefficient.
There are certain parts of rockets that lend themselves much more to re-use than others. In this case, I believe the intent for Ares rockets is to replace the nozzle each flight -- they decided it was cheaper to build consumable thruster nozzles for each flight than to re-process the expensive, intricate cooling designs for keeping a nozzle in good enough shape to use again.
Aikon-
The atmosphere remains a fairly significant factor in satellite design up to altitudes of about 1000km (depending on where you are in the solar cycle; as Sun activity increases, the atmosphere expands). However, your premise remains.. 250km is a VLEO (Very Low Earth Orbit).
Aikon-
Do you mean something like this, which has been around since the 1950s?
Aikon-
There is no "sunny side" of the Moon, nor is there a "dark side"; it has days and nights just like Earth does. The lunar day (or synodic period) is about 29.5 days (..Earth days, that is) long.
Aikon-
Without a seat in parliament, I'm going to go out on a limb and say effectively none.
Aikon-
Funny? More like insightful..
Not that I would use the same pin for my bank card as my iphone, thats crazy talk.
That's only because you know the bank won't let you use 1234 on your card ;)
1234? That's the stupidest combination I've ever heard in my life! The kind of thing an idiot would have on his bank card!
No kidding.. this is like the record industry releasing shitty music without DRM and pointing to its low sales to show that people don't want to buy DRM-free music.
*sigh*
Aikon-
There's also a big difference between making a rocket which can reach escape velocity and making a rocket that can just put something in orbit. All an orbit really is is a constant state of free-fall.
Aikon-
And maybe that they also know how to build and launch an entire satellite, including the radio communications sub-system. Currently operating on-orbit:
Currently under construction/testing:
We also have our own ground-station which is capable of communicating in UHF, VHF, L-band, and S-band.
Aikon-
So it's a good thing that in areas like the maths, sciences, and engineering, LaTeX will reduce the amount of time you spend updating and fixing student handouts.
Aikon-
I'm running Ubuntu Intrepid on a Lenovo T61. It suspends to disk (or RAM) and resumes very nicely as well. However, it didn't always. Up until recently, there was a bug in the iwl4965 driver that prevented re-loading of the kernel module after suspend (or any unloading).
But, it's all fixed now and works great =D
Aikon-
All of the manned missions to the Moon took place in a relatively small area on the near-side. As far as I can tell from the press spiel in the link, M3's mission is to survey the entire surface of the Moon.
At present there is very little data of any sort regarding the far-side of the Moon. Information on the magnetic and gravitational fields is of particular interest because of its importance for orbital prediction, determination, and manipulation.
Aikon-
You must not fly at all then, since with any airplane, the only join between the hull and the sky are the wings.
Aikon-
The new AMC theatre at Yonge and Dundas in Toronto is quad-HD, so 3840x2160 resolution. It looks a little sharper than the traditional projector systems we've become used to, but there are huge advantages in terms of not having to switch reels, not having random black and white spots, etc.; I'm thoroughly enjoying it!
Aikon-
I think a gravity gun would be way cooler in space. Come to think of it, even here on Earth =D
Aikon-
It's an API into specific hardware features only found on nVidia graphics cards; seems to me nVidia's graphics drivers are the perfect place for it.
Aikon-
Looks related to this research done in the late seventies.
C.T. Russell and R.C. Elphic. ISEE observations of flux transfer events at the dayside mangetopause. Geophyiscal Research Letters, vol. 6, pp.33-36, 1979.
Aikon-
From XKCD: Certainty
Aikon-
Please see: http://en.wikipedia.org/wiki/Internal_combustion_engine
Specifically, there are a number of types of engine
that classify as "internal combustion", and jet engines (in the general case, e.g. pump-jets on SeaDoos don't count) are one of those types. And before you go off the handle, rockets are actually a sub-class of jet engine.
Aikon-