4 ms·
Curious: what happened to them? Sure, at this point none should still be in orbit because LEO has too much drag. But did they definitely burn up on re-entry? O
by mabbo 4y ago
Curious: what happened to them?
Sure, at this point none should still be in orbit because LEO has too much drag. But did they definitely burn up on re-entry? Or did the American Government cover the planet in a fine layer of tiny needles?
- panzagl 4y agoStill there, look for SATIDs in the 2360s.
- wumpus 4y agoThose are the clumps large enough to be seen by radar. The needles that successfully deployed came down in 3 years.
- shagie 4y agohttps://www.wired.com/2013/08/project-west-ford/ https://www.wired.com/2013/08/project-west-ford/ > On May 9, 1963, a second West Ford launch successfully dispersed its spindly cargo approximately 3,500 kilometers above the Earth, along an orbit that crossed the North and South Pole. Voice transmissions were successfully relayed between California and Massachusetts, and the technical aspects of the experiment were declared a success. As the dipole needles continued to disperse, the transmissions fell off considerably, although the experiment proved the strategy could work in principle. The successful MEO are still there - https://www.n2yo.com/satellites/?c=37 https://www.n2yo.com/satellites/?c=37
- wumpus 4y agoAs I said, those are the clumps. The individual needles can't be seen by radar and have a high enough surface to mass ratio that they deorbited in 3 years instead of centuries.
- panzagl 4y agoOccasionally NASA will do surveys of smaller objects, but I'm not sure how they would be able to tell if they're still up there since they're not regularly tracked- it's more like 'we scanned volume x and found y objects smaller than we usually track so we think there are z small objects up there overall'. Overall one of the more interesting bits of the 'hold my beer' phase of space exploration.
- wumpus 4y agoIsn't that done by an Air Force radar at... Westford? I didn't think NASA had a radar for that purpose.
- panzagl 4y agoThe radar at Westford is a tracking dish, I think they used one of the bigger phased arrays for the survey I'm thinking of.
- wumpus 4y agoI didn't know NASA had a phased array suitable for such surveys, but of course it's not really my gig -- astronomer, we don't transmit much! I mainly know about the Westford dish because it's used for VLBI and VGOS. I looked for a big NASA phased array, and couldn't find one other than the SOAR proposal. I couldn't figure out if it was actually built or not. Seriously, I'm interested in the details.
- deleted 4y ago[deleted]
- shagie 4y agoAfter digging a bit: https://en.wikipedia.org/wiki/Project_West_Ford https://en.wikipedia.org/wiki/Project_West_Ford > The needles were placed in medium Earth orbit at an altitude of between 3,500 and 3,800 kilometres (2,200–2,400 mi) at inclinations of 96 and 87 degrees. This is problematic as they are MEO not LEO. From https://www.spaceacademy.net.au/watch/debris/orblife.htm https://www.spaceacademy.net.au/watch/debris/orblife.htm - this is off their chart (which goes to 900km and 1000 years). Likewise, https://www.lizard-tail.com/isana/lab/orbital_decay/ https://www.lizard-tail.com/isana/lab/orbital_decay/ only goes up to 500km. https://www.n2yo.com/satellites/?c=37 https://www.n2yo.com/satellites/?c=37 for a tracker.
- JKCalhoun 4y agoI can't decide if they would burn up or not — while referred to as needles, they sound more like very fine wires. Would these short, fine wires fall fast enough to burn up? Or would they more or less float to the ground?