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Two Big Rockets Launched Early Wednesday -- Then One Landed In High Seas (arstechnica.com)
Arianespace and SpaceX both launched rockets this morning between 7:25am ET (11:25 UTC) and 7:39am ET (11:39 UTC). The Ariane 5 ES rocket sent four Galileo satellites into medium Earth orbit (at an altitude of 22,922km) for the European Commission. "These satellites will form part of Europe's own global navigation system constellation," reports Ars Technica. As for SpaceX's Falcon 9 rocket, it launched from the West Cost to deliver 10 Iridium NEXT satellites into a polar orbit 625km above the Earth. Ars reports on how the launches went: Both rockets hit their instantaneous launch windows on Wednesday morning, with the Ariane 5 booster lifting off from Kourou, French Guiana under mostly sunny skies and the Falcon 9 rocket ascending from California through a thick fog layer. The upper stages of both rockets are now in their coast phases before deployment of their satellite payloads.
After the launches, attention turned toward SpaceX's attempt to recover its first stage and payload fairing. The atmosphere offshore, where the Just Read the Instructions droneship was stationed 235km away from the launch pad, had high wind shear. This means wind speeds and directions varied at different altitudes, making it a challenge to come back to the ground in a more or less straight path. This, combined with high seas, made for the "worst" conditions SpaceX has ever tried to land a rocket in, said launch commentator John Insprucker. The cameras on board didn't capture the landing clearly, but afterward SpaceX said the rocket did, in fact, make a safe landing on the droneship. Less certain was the fate of the payload fairing amid the poor weather conditions. "This is an experimental attempt; we're still learning how to catch a fairing out of the air," Insprucker said.
After the launches, attention turned toward SpaceX's attempt to recover its first stage and payload fairing. The atmosphere offshore, where the Just Read the Instructions droneship was stationed 235km away from the launch pad, had high wind shear. This means wind speeds and directions varied at different altitudes, making it a challenge to come back to the ground in a more or less straight path. This, combined with high seas, made for the "worst" conditions SpaceX has ever tried to land a rocket in, said launch commentator John Insprucker. The cameras on board didn't capture the landing clearly, but afterward SpaceX said the rocket did, in fact, make a safe landing on the droneship. Less certain was the fate of the payload fairing amid the poor weather conditions. "This is an experimental attempt; we're still learning how to catch a fairing out of the air," Insprucker said.
Ariane cost: $165-220M per launch, 16,000 kg to LEO.
Falcon 9 cost: $50M per launch (2018), 22,800 to LEO.
Taking the middle of the Ariane cost, it is $12,000 per KG to LEO. The F9 is $2200 per KG to LEO.
Actually a very good question...
LEO satellites are usually orbited low enough that they will naturally re-enter with in a few years of "unpowered" flight, such as after it's run out of fuel or is no longer controllable. So LEO orbits are generally self cleaning over time.
For orbits that are higher, the natural decay times can be quite long (as in practically not going to happen) and in such cases the usual thing is to either plan to deorbit the satellite by putting it into a highly elliptical orbit where it drags in the atmosphere at the low point and letting gravity take it's course, OR you plan a parking orbit out of the way. Such things usually take fuel and active control of the satellite so they are not always successful. Also, some orbits have natural collection points due to the gravity between say the moon and earth. These points are often the final destination of space junk as it's a low energy way to get it out of the way into a place where it will naturally stay without help, which is a good thing.
So for LEO the issue of debris is naturally correcting, though still a bit of a risk to the satellites that operate there because of the relative speed differences which can be very high for objects in different but crossing orbits. However for LEO, there are all sorts of possible orbits and directions so you can usually stay out of each other's way. Form geosynchronous orbits the relative speed differences is quite low, given that the whole point is to make the satellites all stay in one place in the sky. This stacks up a lot of hardware in a very small space though so collisions would be more slow motion train wrecks that won't create a lot of debris than quick obliteration events that generate a lot of fast moving objects.
Of course there are all sorts of highly elliptical orbits used for various types of satellites and these are usually designed to be decaying over time, with their low points being at or near LEO levels. As in most of this stuff, they have a planned way to get the used up hardware out of the way somehow.
So no, we certainly don't convert them to debris, usually, though some have been used for target practice to prove anti-satellite weapons actually can work. Such weapons have been demonstrated by multiple countries, including the USA, China and Russia/Soviet Union.
"File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
Hmmm.... don't know enough orbital mechanics to argue but getting heavier sattelites 8 times further away seems like it might take a much larger rocket than the space-X one. So is there much to compare here?
The two rockets are very comparable. In expendable mode, the Falcon-9 has a greater payload capacity (to the same orbit) than the Ariane 5, 8.3 tons vs 7, but with reuse it is less, only 5.5 tons to GTO.
In rocketry, is is not about power, distance or energy, rather it is thrust and delta-V (change in velocity). Higher orbit means higher velocity.
You need around 10km/s to get to low-orbit, and another 2-3 for the higher Galileo orbit, similar to geosync transfer orbit. So the "8 times further" is misleading.