A quick question about these falling satellites.

I've been thinking about it, and it makes sense that these shuttles have to eventually be retired.
What I do not understand is why we are letting them just kinda fall back to Earth. I mean, would it be that difficult to give a satellite an engine and just fire it at the sun when it's old or something? I mean seriously, why did nobody think of this stuff? We are smart to build a 3500lb telescope that enables to see over 102 million lightyears away, but we can't figure out that if we throw a giant freaking rock in the air it's going to eventually come back down? WTF.

Originally posted by ShadowMonk
I've been thinking about it, and it makes sense that these shuttles have to eventually be retired.
What I do not understand is why we are letting them just kinda fall back to Earth. I mean, would it be that difficult to give a satellite an engine and just fire it at the sun when it's old or something? I mean seriously, why did nobody think of this stuff? We are smart to build a 3500lb telescope that enables to see over 102 million lightyears away, but we can't figure out that if we throw a giant freaking rock in the air it's going to eventually come back down? WTF.

all new sats and what not are equiped with rockets for this reason ect...but at the time they wanted to get them up there not worried about them coming back down and just an fyi there sats not shuttles

Hopefully they ARE just falling satellites.

reply to post by ShadowMonk

Yes, that would be very difficult and expensive thing to do. The satellites does have fuel and can be moved around in orbit, but no way it could be sent to sun or similar. They basically move them to "graveyard orbit" once then run out of fuel and then gravity does rest of the job.

This is no problem usually since most of them burn up in atmosphere.

Spot on. Amazingly, that's the way it is. The vast majority of those scientists working on those flying gizmos don't have a clue what they are actually supposed to be doing there...

reply to post by juleol


Why cant they be aimed at Sun and send them nothing would stop them right?

I was watching a movie from 1984 called Brother from Another Planet an in this movie one of the minor characters stated that years or decaes from now all these satellites would be falling back to earth. Weird it seems as if he was right. Let's just hope that if SHTF that all the satellites don't all come crashing down at once. I have wondere myself why not just keep them up there do they need electricty or power to keep them up there?

Yes. It would be that difficult.

It takes a lot of thrust to get an object with a lot of mass to escape velocity. For example, to break the Apollo command and lunar modules out of Earth orbit, the S-IVB booster required 6 minutes of 200,000 pounds of thrust.
That rocket (including fuel) weighed 253,000 pounds.

Yes, the satellites are not as massive as the Apollo spacecraft but it's still no minor matter.

reply to post by ShadowMonk

The primary consideration in putting a satellite into orbit is weight,lower weight equals less cost for the booster rocket required for it to be put into either geostationary or geosynchronous orbit.

The same holds true for satellites taken up in the shuttle,as the shuttle payload is determined by the boosters required to allow it to escape the earth,s atmosphere.Putting an engine in a satellite would drastically increase the weight after you take into consideration the weight of the motor itself and the fuel load required to support a rocket motor burn sufficient to take it further from the earths gravitational influence.

Obviously it's cheaper for NASA or ESA or whoever is launching the satellites to cope with the aftermath of a satellite falling to earth once it has reached the end of it's operational life(which is after all a very rare ocurrence),but not very comforting if you happen to be standing at the impact point!

reply to post by nake13


Nake, Phage, thank you both for pointing out these factors I had failed to consider. So since letting it fall to Earth seems to be the only feasible option, why don't they build the satellites to... you know, break on the way down, so that it doesn't land in a few ton fireball? It just seems like these are things that should have been considered, given our history with flying space objects and such.

reply to post by ShadowMonk

Standards are being developed to do just that.
Newer satellites are designed with that in mind.

reply to post by Phage


Hooray! Somebody used their brain! There is hope for humanity yet!
Well, that settles that I guess.
*curbstomps thread*

Since it was a great expense to get the materials in orbit finding a way to recycle them in orbit before they burn in the atmosphere might not be a bad plan.

Anyone remember the thread on here recently about Richard Hoagland announcing this back in late August?

I do' just can't remember the title. I believe it was talking about a hexagon shaped craft.....

The problem is with satellites is they have a lot of titanium, and titanium has the highest melting point of all metals not ever achieved during reentry, probably not half the temperature to melt those parts. Plus it was mentioned cheaper materials cause more satellite disables from solar storms so you can't have both worlds, and you aren't going to give each and every satellite enough fuel to reach 25,200 mph to escape velocity when they break down, OH WAIT! If they broke down how do you trigger these rockets to aim them out of earth orbit??!!

One has to realize that in order to lift heavy satellites with enough rocket fuel to end their life plunging into the sun, you are going to have more expendable fuel tanks on the heavy lift rockets that get them to orbit so you will still have masses of metal falling back to earth and most heavy lift rocket fuel tanks LAND, and don't burn up because they just aren't going fast enough after a 2-minute burn, when they are released/jettisoned.

So it seems that the crux of the complaint isn't metal falling back to earth, just certain kinds then huh?

I for one had enough of the rate hikes for satellite receptions, now people want to add to that cost? You have to take into account achieving higher orbits just don't take twice or three times the fuel and heavy lift rockets, it takes exponentially more every hundred miles you want to achieve. I mean logic dictates that if you want to launch more fuel, the heaviest part of the launch, you need bigger rockets to do it, and more fuel.

The amount of fuel that Charles Lindbergh carried on his airplane the Spirit of St. Louis, specially designed to carry fuel, so heavy it almost never took off, with wing supports that blocked any front view, for the whole trip he used 1/10th the fuel heavy lift rockets burn in each and every second of being powered on.

Originally posted by Illustronic
"The problem is with satellites is they have a lot of titanium, and titanium has the highest melting point of all metals not ever achieved during reentry, probably not half the temperature to melt those parts. "

---- Titanium melts at temperatures close to the melting point of steel, you probably meant tungsten ( wolfram) which has the highest melting point of all metals.

reply to post by windlass34


Yes, stupid mixup on my part, I didn't think to check while making the post. More importantly though, little is known of the actual temperatures reached in uncontrolled LEO reentry, its not like they installed sensors on 20-year old satellites, but the point of my post is I doubt reentry ever reaches the melting point of titanium, also considering all of the metal that may be around those parts that have to burn off first.

Now they have taken measurements of many of the points on the Space Shuttle during reentry and the more you look into them, their durations and such, in controlled reentry, I haven't seen any points that exceed titanium melting point. Also quite a bit was recorded during the Apollo years, and those temps fall between the melting points of steels and titanium, still, I mixed up the tungsten and titanium points.