Dud Mars probe's explosion will spare Earth's cities The chief of the Russian space agency has assured the public that the stalled and uncommunicative Mars probe Phobos-Grunt will not smash into a populated area of Earth. Vladimir Popovkin, head of Roscosmos, told reporters that if the wayward spacecraft re-enters the Earth's atmosphere, which he believes is still the worst-case …
The thing is that most of the probe is actually the spacecraft to leave orbit and then fly all the way to Mars and then generate the required power for the experiments and communicate with Earth.
You would have to duplicate all of this for each probe you sent, and it is probably significant. It is a bit like saying instead of flying 220 people on a single Airbus A321, you want to fly them in batches of 10; the plane is so much of what you actually fly that it doesn't make that much sense.
Europe is about to build some; European Data Relay Satellite (EDRS) http://www.esa.int/esaTE/SEM5GGKTYRF_index_0.html. I think the final configuration has 2 in Geo orbit. One is a dedicated sat, and the other 1 is a payload on a commercial communication sat. With this they should have almost continuous coverage of most of the Earth.
However, these will be designed to work with small terminals built into specific satellites, using specific laser (& RF?) wavelengths, and these terminals will need to be steered to point at the EDRSs. I don't think that it would be worth adding a terminal like this to something that is only supposed to be in orbit for a few days.
If you put the relays in geosynchronous orbit, only two or, better, three would be required. Coverage might get a bit thin around the poles, at least theoretically. However, most things planning to leave Earth's gravity well, like a probe headed to Mars, launch into orbits near the equator, so that's not much of a problem practically.
When pieces come down to Earth, it is usually because they were absolutely HUGE before they entered the atmosphere (think MIR), or becuase they are made out of materials that survive the very high temperatures /stresses of re-entry (e.g. spherical titanium tanks, aluminimum-silicon-carbide structures, etc.)
The Russians will know what materials they used, and what sort of size they are. On top of that, some of the larger pieces may well end up smaller once the fuel starts reacting. If they say that it is very unlikely that anything will reach the ground it may be true. (Just because WMD were not found, not everything is a lie :)
Orbital mechanics are tricky things. It could be very much like trying to catch an artillery shell in flight... a little impractical, and any satisfaction you might have from succeeding will be rather brief.
To extend an already daft analogy, its probably like a guy in Canada trying to catch artillery rounds being fired in Afghanistan. Chances of their orbits coming close are incredibly small, if only for safety reasons.
Standard Missile 3. It's already done it once. About the only limitation is that the Russians probably don't have quite as clear an idea of their satellite's location as the Americans did of theirs. (And wouldn't tell even if they did know, perhaps.)
((No joke icon because it isn't really meant as a joke.))
It is a sad state of afairs that a lot of their tech has just wasted away sitting around outside :( In it's day, it did fly, and automatically too, up and back by itself.
If they had caught the capitalism virus sooner, they could've sold all the stuff to museums to be displayed and looked after like the US shuttles. (There is a reasonably well conserved Soyuz in the space museum in Leicester by the way)
Although the American probe doesn't return any soil, it is a monster device with a fascinating landing mechanism. It also has 10 anhydrous testing mechanisms and is going for a very promising target.
Too bad about the Russian probe. Now let us cheer on this probe!
So the probe will somehow be eroded in such a way that the two liquids/gases mix and ignite and blow the thing apart?
More likely it will vent and not mix until large fractions of a kilometre behind the craft as it re-enters at speed considerably in excess of the flame front of the fuel if perfectly mixed.
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