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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.
The fairing has a steerable parachute. It's as big as a bus. They didn't manage to get the ship under it, but "they saw it come down".
Bruce Perens.
It's not just the grid fins and landing burns that make the first stage easier. The rocket does a boostback burn and a reentry burn, both of which help pointpoint where the rocket will end up. The fairing does no burns; the only control over where it will be when its parachute deploys is when it separates and the trajectory of the upper stage at the time. Errors in precision high up are amplified as the fairing descends and enters the atmosphere.
The terminal guidance with the parachute and catching that with a boat is yet another problem on top of that. At least the parachute slows the descent, giving the boat more time to position itself.
"Lock and load, Brides of Christ!"
Not to doubt you, but where did you find those numbers?
Sorry, i should have put the sources. All numbers sourced from wikipedia, but there are many other sources around the net too. Sidebars on the right:
Ariane 5
Falcon 9
The Ariane 5 that launched four Galileo satellites yesterday is the ES variant, capable of putting about 21 tonnes into LEO. It's only flown that particular profile for ATV service missions to the ISS. This is the second ES-variant Galileo mission flown, putting a carrier with four satellites in elliptical orbit which is then circularised at GPS altitude (about 20,000km). Originally the Galileo satellites were being launched two at a time by Soyz-Fregat rockets but one launch went wrong and ESA decided to take the rest of the launches "in-house". It worked out cheaper to fly four satellites at a time on the heaviest-lift variant of the Ariane V compared to two at a time on the less-capable ECA variant.
As for the Falcon 9 FT it can only, IIRC, deliver 20-odd tonnes to LEO if it flies without recovery in mind -- no landing legs, no first-stage fuel reserve for landing etc. This makes for a more expensive launch cost.