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China’s told the world it plans to get into the recoverable satellite business. The nation’s launched and recovered satellites since the 1960s. Early missions may have been surveillance efforts that returned films to Earth to provide photographic reconnaissance. More recent missions have allowed experiments to be conducted in …
I believe school children in WW2 were asked to collect walnut shells and then their school would send them to a PO BOX. The military were looking at using the shells to make heat shields.
I can't find a link on Google though. Some one with a New Scientist subscription might be able to dig it out.
Horse Chesnuts aka 'Conkers' were collected by school children as a supplementary source of starch for the manufacture of acetone, which was then used to make cordite. I believe this happened in both world wars, but may have been more for propaganda then practical use.
Oak is a particularly fire-resistant timber because it is very strong and dense so that it chars rather than burns, forming a protective layer of charcoal that keeps oxygen at bay. This is recognised (or certainly used to be) in the UK Building Regulations for fire resistance and it makes oak a more economic building material than you might expect. Run that up to Mach 20 or whatever and it becomes an ablative or sacrificial material similar to that used on the original American X-15 sub-orbital rocket plane. Oak is kinder to the environment than that disgusting and toxic chemical brew, too. I don't know about the weight though, that would add a lot to the fuel costs.
"Oak is a particularly fire-resistant timber because it is very strong and dense so that it chars rather than burns"
There's at least one type of eucalypt so dense that it's known as "firebricks" - it's almost impossible to work as it ruins metal tools and it's around twice the density of water.
'There's at least one type of eucalypt so dense that it's known as "firebricks" - it's almost impossible to work as it ruins metal tools and it's around twice the density of water.'
Only one problem with using eucalypts as heat shields, eucalyptus oil tends to burn far too easily. Just ask any Australian fire fighter.
Webbing for oaken heat shield produced this confirmatory article:
...BUT same article refers to a nuclear test site manhole cover being the first object launched (unintentionally) into space (nuclear cannon) - which (sadly) from the following article appears to be urban myth:
Because its getting damn crowded up there.
The planned constellations of several thousand micro-sats must have an impact on other launches as these try to find a launch window that suits the mission objectives while avoiding the risk of hitting a micro-sat. If you were to point out that launching one of these mega-constellations looks downright selfish and totally inconsiderate of other satellite users I would not disagree.
J2C offered, "Couple of thousand [satellites] shouldn't be an issue. Still plenty of separation."
Arguably correct. Too bad there's probably about 14,000+ objects now.
Wiki: "The United States Space Surveillance Network (SSN) currently tracks more than 8,000 man-made orbiting objects ...that are 10 centimeters in diameter or larger."
> 1) We're running out of room
That's not an argument to make them recoverable, just to provide provision for a controlled suicide burn at end of life. Many larger sats do this already.
> 2) The chances of some random lump of metal landing on your head are increasing
Again, this isn't an argument for recoverable satellites. At best, it's an argument for a controlled suicide burn. But sats which are large enough to do damage can generally already do this. Micro-sats really don't need to - nothing will make it back through.
All of those unrecoverable satellites are up there because aliens ha e tricked the human race into sending thousands of bits of metal into orbit around the Earth. When there are enough of them they will weld them together into a mini Dyson sphere to stop humans getting off the planetand contaminating the galaxy with never ending war, reality shows and unintelligible gangster rap.
"More recent missions have allowed experiments to be conducted in microgravity, an environment China feels is a fine place to grow seeds that produce hardier plants than their terra-bound cousins."
That gives me an idea for a new line of business for someone - probably Amazon.
Grow stuff in orbit in a micro-gravity, and provide a (cooked) food delivery service; customer orders something from the menu, and the order is dropped
on to them from orbit, using the heat of re-entry to cook it.
I'm told that Apollo had an oak component in its heat shielding. Once it chars, oak is remarkably resistant to heat and insulates well I'm led to understand.
Works well against cannonballs too, I understand, which is why the great oak forests of England were strip-mined into extinction by Henry the Eighth.
Good job too. Dealt with the Spanish Menace, the French Menace and the incipient Werewolf Menace in one go.
..Those who wish to conduct cheap microgravity experiments often turn to sounding rockets, which offer only a few minutes of space flight and no return trip..
Umm. My understanding of a sounding rocket is that it goes straight up. This gives a bit of microgravity once the booster stops and it cruises up... but then it turns round and comes straight down again.
So there's quite a rapid return trip. And one which, if you include a parachute, you ecperiment might survive...
Anyone who's tried to laser cut a digestive can tell you that they're surprisingly resistant, so I reckon a huge one would be worth a try for a heat shield. Getting SpaceX to replace their boat-borne catcher's mitt with a giant cup of tea would be a fine thing, too.
It would be costly to go up there and grab them, in the style of Elon Musk with returning rockets to a platform. so what will they do, make a nice big landing pad or something ?
NO! lets just keep them falling out of the sky. China's reign/rain may just be satellites.
What with all that space junk up there, where a Mylar face panel or a tiny nut hurtling around could spell oblivion for a satellite or astronaut.
It would be good to clean it up.
Perhaps China might elect itself Earth's space police and garbage collectors. do stop and wait.
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