| Altitude in Miles | Satellite Types |
| 100-300 | shuttles, space stations, spysats, navsats, hamsats |
| 300-600 | weather sats, photo sats |
| 600-1,200 | spysats, military comsats, hamsats |
| 3,000-6,000 | science sats |
| 6,000-12,000 | navsats |
| 22,300 (stationary) | communications, broadcast, weather |
| 250-50,000 (elliptical) | early-warning, Molniya broadcast, communications, spysats, hamsats |
Aluminium starts melting at 660.3 °C
Fortunately for me, I went to school before they destroyed education. So, drawing upon what I learned before eighth grade, I'd like to point out a few things without going into a dissertation on thermodynamics, heat transfer, ect.
ReplyDeleteTemperature and heat are not the same thing. Temperature is a measure of the average molecular activity of a substance while heat is the total energy of same based on mass.
On the surface the atmosphere is densest with gazillions of molecules crammed together, so when the temperature is high there is lots of molecular activity and lots of mass and therefore lots of heat.
As you ascend, the air gets increasingly thinner with less and less mass and less and heat while what molecules are present can be very active and at high temperature.
In other words, if you go out far enough, a brass monkey could freeze his balls off even though it's hundreds of degrees outside.
The friction of air molecules in the thermosphere do not transfer heat well because of their scarcity. That makes perfect sense to me. Problem solved.
ReplyDeleteWhat effect would the temperature have on a satellite that is in orbit for years?
ReplyDeleteDo you mean to say that no heat would transfer to the molecules of the satellite even though it is in direct sunlight for years?
If there is no energy transfer, then wouldn't all the energy from the sun continue to store up in the satellite?
The satellite would reflect or absorb radiant energy from the sun which could cause heating but satellites are designed to regulate that through reflection, insulation, dissipation etc. The discussion was about the thermosphere.
ReplyDeleteIf a highly polished brass monkey were to be inserted into orbit I am confident it would reflect all of the sunlight and the monkey would freeze.
well, since the sun is electomagnetic and there are no atmosphere molecules in space for the energy to heat anything up, it would stand to reason that space is minus 275 degrees and an elephant would freeze in one second, or less.
ReplyDelete@EP: You said: Temperature is a measure of the average molecular activity of a substance while heat is the total energy of same based on mass.
ReplyDeleteThen wouldn't the measure of the average molecular activity of all the substance in thermosphere be 1,000 degrees (C) during the day? And doesn't the average measure drop to 700 degrees at night?
And since there is a change between the day and the night temperature, couldn't we reason that the change is due to the sun? i.e. that the change in the energy of the molecules of the objects in the thermosphere is due to the sun?
And since the average molecular activity never drops below that minimum, couldn't we say that the energy is permanently "retained" above 700 degrees?
Now if an object is sent into the thermosphere, why should it not also absorb the energy being given off by the sun?
You say that the magical objects we send into the thermosphere are not affected by the sun. They are immune from the sun.
You credit reflection, insulation, dissipation with the reason why. They have a perfect reflectivity that keeps all the energy away. There is no energy that gets by the magical reflectors. And if any energy does get by the reflectors, the magical insulation is able to keep energy from the sensitive parts without storing any energy?. And unlike everything else in the thermosphere, they don't store any heat over the day that is not dissipated at night. Everything else in the thermosphere will not dissipate below 700 degrees, but the magical things we send up dissipate everything so that they get down to FREEZING.
It's too bad no one can test any of these magical properties. But I am confident that NASA would not lie about anything.