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Old 2013-07-03, 21:04   #958
ewmayer
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Today's interesting weather factoid is related to the intense week-long heat wave which has blanketed the Western U.S.: last night's *low* temperature in Death Valley was 104F = 40C.

"But it's a dry heat..."
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Old 2013-07-04, 01:12   #959
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Brutal. I was arriving on a plane at 1:00 in the morning in Abadan, Iran once, and the pilot came on the intercom to welcome us to Abadan, where the temperature had "cooled down to a pleasant 103 degrees F". That was before air-conditioned jet-ways; really weird walking down the steps from the plane and across the tarmac, in the middle of the night, yet incredibly hot.

Norm
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Old 2013-07-06, 14:40   #960
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Un manned rocket lft-off, then land back on its own launchpad (vertically, and without chute)
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Old 2013-07-06, 16:41   #961
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That is amazing, though it must be a real fuel hog.
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Old 2013-07-06, 17:04   #962
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part of the discussion on slate :
Quote:
Originally Posted by gopher65
1) They don't "avoid" the rocket equation. This idea causes the payload-to-orbit of any rocket that uses it to drop by ~40%. The reason this idea is still good is that the fuel on (for instance) a Falcon 9 only cost about 200,000 dollars per launch. The other 45 million is the cost of the rocket itself. Think about it this way: how much would a flight from London to New York cost if you threw the 747/A380 into the garbage at the end of every flight (and built a new one for the next flight)? Flights would be incredibly expensive, just like disposable rocket launches are.

Once we have fully reusable rockets, a trip to orbit will be in approximately the same price range for customers as a first class seat on an international flight.

2) The first stage of a rocket only travels one to two hundred kilometres downrange. So they wouldn't need to "launch from Florida, land in Africa". They could launch from Florida... and pick up the first stage a short distance away. There is a small fuel cost to flying it back to the pad, but that cost is probably less than what it would cost to ship it in an oversize trailer by ground. The second stage actually makes orbit, so it can orbit as many times as it needs to and then come down wherever they want.
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Old 2013-07-06, 17:08   #963
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Thanks for the added info. Those are some interesting points on cost comparisons.
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Old 2013-07-06, 17:49   #964
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Quote:
Originally Posted by kladner View Post
That is amazing, though it must be a real fuel hog.
Single engine, throttled way back, and an almost empty tank make for better fuel economy.

Their idea of putting an ablative coating on the top of the second stage tank is innovative.
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Old 2013-07-07, 01:12   #965
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The above links prompted me to wax nostalgic and read the Wikipage on the Saturn V - thanks for the memories. Even almost 50 years later, I still am in awe of the profound engineering feat that rocket represents.

Interestingly, note that there were for a while plans involving use of the Saturn V's mighty first stage (the S-IC) for heavy-lift, and moreover in reusable fashion:
Quote:
The Space Shuttle was initially conceived of as a cargo transport to be used in concert with the Saturn V, even to the point that a Saturn-Shuttle was proposed, using the winged shuttle orbiter and external tank, but with the tank mounted on a modified, fly-back version of the S-IC. The first S-IC stage would be used to power the Shuttle during the first two minutes of flight, after which the S-IC would be jettisoned (which would then fly back to KSC for refurbishment) and the Space Shuttle Main Engines would then fire and place the orbiter into orbit. The Shuttle would handle space station logistics, while Saturn V would launch components. Lack of a second Saturn V production run killed this plan and has left the United States without a heavy-lift launch vehicle. Some in the U.S. space community have come to lament this situation,[who?] as continued production would have allowed the International Space Station, using a Skylab or Mir configuration with both U.S. and Russian docking ports, to have been lifted with just a handful of launches. The Saturn-Shuttle concept also would have eliminated the Space shuttle solid rocket boosters that ultimately precipitated the Challenger accident in 1986.
IMO, killing the Saturn V-based booster program is one of the most short-sighted, idiotic decisions in the history of manned space flight. "Cost savings", my butt - I bet merely the post-Challenger-disaster *redesign* of the shuttle solid boosters cost more than a second Saturn V S-IC production run would have.
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Old 2013-07-11, 19:03   #966
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Rare Record of Chinese Classics Discovered: Muddy bamboo strips, dating from about 300 B.C., turn out to contain texts as important to China's history as ancient Greek or Latin texts are to the West.
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Old 2013-07-11, 19:59   #967
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Default The blue, blue glass of home.

Nice observation of a hot Jupiter.
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Old 2013-07-11, 20:33   #968
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Solar system has trailing tail, just like comet



Quote:
CAPE CANAVERAL, Fla. (AP) — NASA can prove it now. Our solar system has a tail, just like comets.
Scientists revealed images Wednesday showing the tail emanating from the bullet-shaped region of space under the grip of the sun, including the solar system and beyond. The region is known as the heliosphere, thus the name heliotail
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