Mercury space probe runs out of fuel and crashes into planet

[norseamd]

As for solar panels, I don't think there's a way to create propulsion in space using electricity. You could electrolyse water and make hydrogen but then you have to carry water and you'd run out of that too. Fuel is higher density.

Think he is talking about solar powered ion engines. He might not know that ion engines are on the spacecraft that use solar panel power generation.

 

[BUTCH1]

Wow, OP fail here, didn't bother to read up on the fact that this was an anticipated event after an 11 year mission which was a complete success. As for the question "why don't our satellites crash" they are parked in a "Geo-stationary" orbit and need to use small amounts of propellant to move around now and then. NASA wanted much closer hi-res pictures of Mercury which entailed a much lower orbit that had to be maintained by using propellant.

 

[destrekor]

also, Mercury has ice?!
even on the dark side of the planet, I would never have imagined that it's cold enuf to form ice

Mercury is far enough away to have ice, given the fact that there is no trace of atmosphere with which to hold in heat. Mercury is tidally-locked, so without an atmosphere, a lot of heat does not make it to the "dark side" of the planet.

Think about the Earth and the Moon: when the surface of the Moon is hit by sunlight, it can reach temperatures around 253ºF (123ºC). Without the Sun, the temperatures plunge to -243ºF (-153ºC).
Yet, nowhere on Earth (on the surface) do we experience either of those temps. Atmospheres both insulate and help absorb heat, distributing that heat to the atmosphere.

In short, if close to the sun but in complete shadow, it can get wicked cold. Heat in space only works on surfaces - the space around a star isn't hot, that heat only interacts with surfaces, so if you erected a giant shield near the sun and floated behind it, you'd still freeze if not protected by an environmentally-controlled suit. Without that shield, you'd be incinerated on contact (again, unless your suit is reflective and properly designed).

Well if true then that would be because of the gravity of other objects like the Sun or Jupiter.

No, it is not because of other gravitational influences. It is due to velocity and origin. The moon was formed from material ejected from the Earth after a massive impact when the Earth was still young and more molten than today. It was formed and got captured into an orbit with the right velocity and mass to maintain an orbit that, for all intents and purposes, is stable.

No orbit is stable 100%. All "stable" objects are either ever so slowly migrating closer to the object it orbits, or slowly increasing the orbit and will eventually break free. Even then, orbits will likely just become eccentric and distant, and the only time they will "break free" is when other objects have an opportunity to exert enough gravitational influence and capture the orbit.

No artificial satellite above Earth maintains a stable orbit indefinitely, they all need fuel to apply micro-corrections from time to time. The less mass an orbital object has, and the closer they are, the more difficult it is to establish an orbit without fuel.

Planets and stars may be in the most stable orbit you may imagine, but they too still are moving away or toward the objects they orbit, it is just almost impossible to perceive this difference because this whole system is around today and evolved the way it is because of how impossibly slow their orbits change.

Planets and moons and other satellites have come and gone in our solar system, and we cannot see them because their orbits were far less stable or more eccentric.

 

[destrekor]

Wow, OP fail here, didn't bother to read up on the fact that this was an anticipated event after an 11 year mission which was a complete success. As for the question "why don't our satellites crash" they are parked in a "Geo-stationary" orbit and need to use small amounts of propellant to move around now and then. NASA wanted much closer hi-res pictures of Mercury which entailed a much lower orbit that had to be maintained by using propellant.

Not all satellites are geo-stationary. But you are otherwise correct.

 

[destrekor]

Think he is talking about solar powered ion engines. He might not know that ion engines are on the spacecraft that use solar panel power generation.

Ion engines must still have a gas to propel. Solar energy alone does not create ionized thrust: the electrical energy ionizes appropriate gasses. Of which there is very little in space.

 

[ctark]

Because physics. It is "orbitally falling" to Earth right now.

No its not, its moving away from earth right now. The moon use to be much closer.

 

[JSt0rm]

http://en.wikipedia.org/wiki/Lagrangian_point#L2 < That gravity well is where the James web space satellite will sit. Pretty cool really.

 

[Fanatical Meat]

^^^yeah its a piece of Earth

 

[JSt0rm]

^^^yeah its a piece of Earth

god made it 6000 years ago

 

[BUTCH1]

Not all satellites are geo-stationary. But you are otherwise correct.

Yea, I know that weather satellites for instance do move around on occasion (usually when another one fails and they need it moved for coverage) but for the most part it would make little sense to put a satellite in an orbit where it has to use propellant on a regular basis to maintain it's position.

 

[norseamd]

Ion engines must still have a gas to propel. Solar energy alone does not create ionized thrust: the electrical energy ionizes appropriate gasses. Of which there is very little in space.

Right but from his perspective he probably only sees the solar panel equipment and he knows that spacecraft use this power to move but he might not have known that there were ion engines.

 

[Ichinisan]

Well if true then that would be because of the gravity of other objects like the Sun or Jupiter.

No. It's because it's moving ever so slightly too fast for a perfect orbit.

Even if it had a perfect orbit, its gravity or Earth's gravity would capture space dust and meteorites and the masses would change, making the orbits ever so slightly imperfect. If the moon is slightly too slow for the relative masses of the moon and Earth, the orbit decays. Slightly too fast (as it currently is), and we eventually lose it into space. We'll all be dead long before that happens though.

 

[crashtech]

@destrekor: Mercury is not tidally locked. It has a very long day (58+ Earth days).

 

[Paratus]

TIL.

As for how it sends tweets my guess is it sends data to a NASA server first, then they eventually made the program to put that data on twitter.

As for solar panels, I don't think there's a way to create propulsion in space using electricity. You could electrolyse water and make hydrogen but then you have to carry water and you'd run out of that too. Fuel is higher density.

That's not entirely accurate.....

http://forums.anandtech.com/showthread.php?p=37368720#post37368720

 

[destrekor]

@destrekor: Mercury is not tidally locked. It has a very long day (58+ Earth days).

Ooops, right you are right, my bad!

It does have an exceptionally slow rotational period, a version of gravitational lock that is not tidal lock but something extraordinary in its own right. This is similar to the inner satellites of Jupiter, which, I believe, rotate once per orbital period. It's a lock, but not a perfect tidal lock.

 

[destrekor]

Yea, I know that weather satellites for instance do move around on occasion (usually when another one fails and they need it moved for coverage) but for the most part it would make little sense to put a satellite in an orbit where it has to use propellant on a regular basis to maintain it's position.

Satellites do not have to burn excessive propellant in order to achieve ideal orbits that are not geostationary.

Almost every single spy satellite has an orbital period. The ISS orbits. All mapping satellites (spy or not) orbit.

Some GPS and similar satellites have a gravitational lock with the Earth, but still orbit at a pace other than 1:1, typically twice per day. GSO orbits, quite far from the Earth (relatively speaking), are indeed stationary. Everything close, however, have orbital periods based on variables at time of launch, most planned for whatever reason. Mapping, "spy", and orbital stations, all orbit at periods based upon initial variables or at a calculated rate. Some radio and TV satellites have similar orbital periods, whereas most anymore are GSO.

 

[norseamd]

Honestly I had somewhat just thought if something entered orbit then the planetary satellite probably had sufficient gravity to keep the orbiter falling down. Otherwise I would have just thought potential orbiting objects would just slingshot instead of entering orbital laps.

The formation of the Moon would be different then regular orbital capture as it was formation of ejected planetary material in the orbit after the catastrophe?

 

[drebo]

Who was the girl in that video? Fuck she was hot. I'd slam my probe into her...

 

[Oceanas]

Yea, I know that weather satellites for instance do move around on occasion (usually when another one fails and they need it moved for coverage) but for the most part it would make little sense to put a satellite in an orbit where it has to use propellant on a regular basis to maintain it's position.

I guess it depends on what you define "regular" as. If the satellite is low enough, atmospheric drag will slow it down and decay the orbit, so there will need to be periodic boosts to correct the orbit (like with the ISS). For Geo satellites, atmospheric drag is a negligible contributor, but other factors such as irregularities in the distribution and strength of Earth's gravity, solar wind, and Earth/Moon/Sun gravitational interaction will cause disruptions to the orbit.

Geo satellites must perform North/South and East/West station-keeping burns to stay in the proper orbit. In addition, regular burns are conducted to desaturate reaction wheels. There are different techniques (high vs low thrust) and different schedules to achieve all of the required burns, but they can be performed as often as daily (but can be monthly, every couple of months, and yearly). The required amount of fuel for the burns vs the size of the fuel supply (at least the fuel supply at the start of the mission) is low. North/South burns require the most fuel, so these are typically suspended first when fuel starts running low. This causes the satellite to start fluctuating its position North/South over a 24 hour period.

No. It's because it's moving ever so slightly too fast for a perfect orbit.

Even if it had a perfect orbit, its gravity or Earth's gravity would capture space dust and meteorites and the masses would change, making the orbits ever so slightly imperfect. If the moon is slightly too slow for the relative masses of the moon and Earth, the orbit decays. Slightly too fast (as it currently is), and we eventually lose it into space. We'll all be dead long before that happens though.

The Earth actually net loses mass every year via Hydrogen escape to space. In any case, the amount of mass the moon and Earth accumulate via dust and meteorites is an incredibly negligible amount versus the existing mass of either.

The reason the moon is (very slowly) moving away from the Earth is due to tidal acceleration. The tidal bulge that the moon's gravity creates on Earth is slightly ahead of the moon's orbit because of the speed of Earth's rotation. This causes Earth to exert a pull on the moon in the direction of its orbit, which causes a transfer of angular momentum to the moon, and increases the size of its orbit. Since we are losing angular momentum to the moon, days are getting longer as the Earth rotates slower.

Honestly I had somewhat just thought if something entered orbit then the planetary satellite probably had sufficient gravity to keep the orbiter falling down. Otherwise I would have just thought potential orbiting objects would just slingshot instead of entering orbital laps.

The formation of the Moon would be different then regular orbital capture as it was formation of ejected planetary material in the orbit after the catastrophe?

Well, the Earth/Moon situation is due to a particular way to transfer angular momentum between bodies. There are other ways, and there are probably scenarios where a satellite capture could lead to a similar situation, but I can't really speak to that.

A bunch of the other satellites we can observe in the solar system, i.e. the gas giant systems, consists of many satellites in orbit around a planet. When there are many satellites, they can enter into orbital resonance with each other (and other perturbations), which can negate the effects of tidal acceleration and lead to other things such as massive amounts of tidal heating.

Also, the moon is in a prograde orbit, meaning it orbits in the same direction as Earth. That's what allows Earth to pull the moon in the direction of its orbit. If the moon was in a retrograde orbit, meaning orbiting against the rotation of Earth, it would actually be decaying the moon's orbit. Jupiter has a bunch of satellites that are in retrograde and have decaying orbits as a result.

 

[gorcorps]

Who was the girl in that video? Fuck she was hot. I'd slam my probe into her...

They showed her name as soon as she was on screen

 

[Paratus]

I guess it depends on what you define "regular" as. If the satellite is low enough, atmospheric drag will slow it down and decay the orbit, so there will need to be periodic boosts to correct the orbit (like with the ISS). For Geo satellites, atmospheric drag is a negligible contributor, but other factors such as irregularities in the distribution and strength of Earth's gravity, solar wind, and Earth/Moon/Sun gravitational interaction will cause disruptions to the orbit.

Geo satellites must perform North/South and East/West station-keeping burns to stay in the proper orbit. In addition, regular burns are conducted to desaturate reaction wheels. There are different techniques (high vs low thrust) and different schedules to achieve all of the required burns, but they can be performed as often as daily (but can be monthly, every couple of months, and yearly). The required amount of fuel for the burns vs the size of the fuel supply (at least the fuel supply at the start of the mission) is low. North/South burns require the most fuel, so these are typically suspended first when fuel starts running low. This causes the satellite to start fluctuating its position North/South over a 24 hour period.


The Earth actually net loses mass every year via Hydrogen escape to space. In any case, the amount of mass the moon and Earth accumulate via dust and meteorites is an incredibly negligible amount versus the existing mass of either.

The reason the moon is (very slowly) moving away from the Earth is due to tidal acceleration. The tidal bulge that the moon's gravity creates on Earth is slightly ahead of the moon's orbit because of the speed of Earth's rotation. This causes Earth to exert a pull on the moon in the direction of its orbit, which causes a transfer of angular momentum to the moon, and increases the size of its orbit. Since we are losing angular momentum to the moon, days are getting longer as the Earth rotates slower.



Well, the Earth/Moon situation is due to a particular way to transfer angular momentum between bodies. There are other ways, and there are probably scenarios where a satellite capture could lead to a similar situation, but I can't really speak to that.

A bunch of the other satellites we can observe in the solar system, i.e. the gas giant systems, consists of many satellites in orbit around a planet. When there are many satellites, they can enter into orbital resonance with each other (and other perturbations), which can negate the effects of tidal acceleration and lead to other things such as massive amounts of tidal heating.

Also, the moon is in a prograde orbit, meaning it orbits in the same direction as Earth. That's what allows Earth to pull the moon in the direction of its orbit. If the moon was in a retrograde orbit, meaning orbiting against the rotation of Earth, it would actually be decaying the moon's orbit. Jupiter has a bunch of satellites that are in retrograde and have decaying orbits as a result.

This man knows of what he speaks! :thumbsup:

 

[Smoblikat]

Then how does the moon stay around the earth for 3 billion years?

BOOM HEAD SHOT. Go ahead sciency dudes, feed us more lies, we now know the truth.

 

[destrekor]

I guess it depends on what you define "regular" as. If the satellite is low enough, atmospheric drag will slow it down and decay the orbit, so there will need to be periodic boosts to correct the orbit (like with the ISS). For Geo satellites, atmospheric drag is a negligible contributor, but other factors such as irregularities in the distribution and strength of Earth's gravity, solar wind, and Earth/Moon/Sun gravitational interaction will cause disruptions to the orbit.

Geo satellites must perform North/South and East/West station-keeping burns to stay in the proper orbit. In addition, regular burns are conducted to desaturate reaction wheels. There are different techniques (high vs low thrust) and different schedules to achieve all of the required burns, but they can be performed as often as daily (but can be monthly, every couple of months, and yearly). The required amount of fuel for the burns vs the size of the fuel supply (at least the fuel supply at the start of the mission) is low. North/South burns require the most fuel, so these are typically suspended first when fuel starts running low. This causes the satellite to start fluctuating its position North/South over a 24 hour period.


The Earth actually net loses mass every year via Hydrogen escape to space. In any case, the amount of mass the moon and Earth accumulate via dust and meteorites is an incredibly negligible amount versus the existing mass of either.

The reason the moon is (very slowly) moving away from the Earth is due to tidal acceleration. The tidal bulge that the moon's gravity creates on Earth is slightly ahead of the moon's orbit because of the speed of Earth's rotation. This causes Earth to exert a pull on the moon in the direction of its orbit, which causes a transfer of angular momentum to the moon, and increases the size of its orbit. Since we are losing angular momentum to the moon, days are getting longer as the Earth rotates slower.



Well, the Earth/Moon situation is due to a particular way to transfer angular momentum between bodies. There are other ways, and there are probably scenarios where a satellite capture could lead to a similar situation, but I can't really speak to that.

A bunch of the other satellites we can observe in the solar system, i.e. the gas giant systems, consists of many satellites in orbit around a planet. When there are many satellites, they can enter into orbital resonance with each other (and other perturbations), which can negate the effects of tidal acceleration and lead to other things such as massive amounts of tidal heating.

Also, the moon is in a prograde orbit, meaning it orbits in the same direction as Earth. That's what allows Earth to pull the moon in the direction of its orbit. If the moon was in a retrograde orbit, meaning orbiting against the rotation of Earth, it would actually be decaying the moon's orbit. Jupiter has a bunch of satellites that are in retrograde and have decaying orbits as a result.

Thank you for contributing!

I am familiar with all that, but it's been so long that my knowledge of the specifics has dwindled so I cannot explain with scientific terms/accuracy. That, and I never was well-studied in the math of any of it, lol. Just enough to have a grip on the fundamentals.

 

[IronWing]

Impact crater, eh? Would that be an Hg Well?








I slay me.

 

[destrekor]

Impact crater, eh? Would that be an Hg Well?








I slay me.

:awe: