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Old 02-07-2018, 04:54 PM   #11 (permalink)
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It's all down to turn-around time. SpaceX talk about an operation that would be like a busy airport. ...or airports.
Sure, turn-around time is important when you have a full schedule. Not important at all when you've got weeks/months between launches. Besides, doesn't it still take several days to prep those boosters for another launch? I find it hard to believe that retrieval is the slow part of the process.

I'd really like to see footage of the core crash yesterday. There has to be footage, right? At least a feed from the barge.

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Old 02-07-2018, 05:08 PM   #12 (permalink)
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I was afraid you miss my edit at #7.

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Originally Posted by myself
Also, just before the synchronized landing, You can see the first stage flame out most of it's rockets just before the barge is enveloped in smoke and flame. ...then the Space X rep bounces out all happy and says "We got everything we wanted". What he meant was "...just enough mayhem to keep Elon happy!"

If you're not breaking enough you're not innovating enough.
SpaceX want to land the boosters right back on the launch cradle. The're not quite there yet.

[saltwater corrosion]
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Old 02-07-2018, 06:11 PM   #13 (permalink)
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Have a "spare" (or two) as backups...swap them "in" as needed when recovered unit(s) aren't usable anymore (or lost).
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Old 02-08-2018, 03:26 PM   #14 (permalink)
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The Verge reports that Starman overshot Mars:

https://www.theverge.com/2018/2/6/16...elon-musk-mars

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Before the Tesla launched, Musk said that there was an extremely tiny chance that the vehicle would ever hit Mars, and that seems to hold true. Within the next decade, the roadster will make its closest approach to Mars in October of 2020, coming within 4.3 million miles, according to Jonathan McDowell, an astrophysicist at Harvard and spaceflight expert. He also figured out the next time the Roadster gets “close” to Earth is in March of 2021, when it passes within 28 million miles of our planet.
I wonder if the tires survived the Van Allen Belts. And if they were deflated so they wouldn't pop.
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Old 02-08-2018, 03:34 PM   #15 (permalink)
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I wonder if the tires survived the Van Allen Belts. And if they were deflated so they wouldn't pop.
Was wondering about that too. The tires are subject to direct sunlight, and they are black which will absorb much of that energy. Since the vacuum of space insulates, it would get extremely hot. Perhaps they were filled with nitrogen so they wouldn't oxidize. In that case, the tires just have to resist getting gooey and deforming. Perhaps they are capable of withstanding a couple hundred degrees F and relatively low pressure.
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Old 02-08-2018, 04:35 PM   #16 (permalink)
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Apparently, most people are wondering why they can't see the stars on their TV, when you can go out at night in Montana and they're right there.
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Old 02-11-2018, 08:03 PM   #17 (permalink)
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Quote:
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Was wondering about that too. The tires are subject to direct sunlight, and they are black which will absorb much of that energy. Since the vacuum of space insulates, it would get extremely hot. Perhaps they were filled with nitrogen so they wouldn't oxidize. In that case, the tires just have to resist getting gooey and deforming. Perhaps they are capable of withstanding a couple hundred degrees F and relatively low pressure.
The car was put into a slow rotation to heat up both sides of the car evenly (and maybe more importantly the camera equipment).

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I don't understand how landing the first stage is cheaper in the long run than using a parachute and recovery apparatus.

Extra fuel has to be loaded on the booster for the purpose of decelerating and landing it. When you load extra fuel on a booster, you have to load several times more fuel just to accelerate that extra fuel. In other words, most of the fuel spent by a rocket is used merely to accelerate the weight of the fuel. Finding ways to reduce the need for small amounts of fuel ends up allowing larger amounts of fuel to be saved.

How is the weight and simplicity of a parachute a disadvantage compared to the weight and complexity of powered landing and control systems?
A parachute would weigh less than the extra fuel, but doing controlled landing of a rocket that large into anything but water is very difficult. If you wanted to land on a barge with a parachute you would need a very complex and expensive apparatus to catch the rocket without damaging it. You'd also risk damaging a very expensive ship and apparatus. You'd also need a control system for controlled autonomous gliding of the rocket to a specific location. That's only ever been done with much smaller equipment, usually with helicopter capture.

Landing the rocket in the ocean with parachutes is fairly easy. NASA did it with the Shuttle boosters. The problem is that salt water is very bad for engines, especially when they're hot. Refurbishment would be very expensive, as it was for NASA even with their much simpler solid rocket boosters. You'd also need a large boat with a crane to retrieve the rocket. It ends up being a much more expensive proposition, especially since for most payloads, you don't actually need the extra payload capability.

Parachutes would also be impossible for SpaceX's upcoming BFR rocket, which is much larger. Parachute landings also don't work for landing large payloads on Mars, which is SpaceX's primary goal.
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Old 02-12-2018, 12:20 AM   #18 (permalink)
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If I was Musk I'd be shooting for Uranus first.
I love that planet. You know Sir William Herschal wanted to name it The Herschal Highway but after some resistance he went with Uranus. Seriously he called it the Georgian planet so we should call it Georgia, butt some German thought Uranus was better, much to the cheers of 12-70 year old boys everywhere.
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Old 02-12-2018, 12:24 AM   #19 (permalink)
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A vehicle capable of propulsive landing is suitable for landings with or without atmosphere. The BFR will have two different sized rocket bells for operation in or out of an atmosphere.
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Old 02-12-2018, 05:30 AM   #20 (permalink)
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Shame Musk wasn't in the drivers seat at the time. Would have made the world a little better.

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