Posts by Vulch 598 publicly visible posts • joined 28 May 2008
It's quite often done by just turning on the engine but not lighting the blue touchpaper. Rotate the stage through 180 degrees so the engine points along the orbit, open the valves and you get a bit of thrust slowing it but without the risk of toasting the expensive payload that has just been dropped off.
The cutaway looks better than the actual car. Leave the doors off, put Lotus 7 style mudguards over the wheels instead of extending the bodyshell and make the top over the gubbins at the rear a flat deck with some tie-down points so you've got a bit of load carrying capacity and you've got a decent fair-weather run-about.
Replying a week later but at least I'll be able to find it next time...
Actually, if that 16 million is for the first stage rather than the whole F9 it does fit with advertised rates. A standard launch is being priced at 60 million, a Heavy launch 90. It has been suggested that the first stage makes up two thirds of the hardware cost so with a fixed cost per launch (y) plus a hardware unit cost (x) we have F9R as 3x + y = 60 and F9H as 7x + y = 90. Solving that gives x = 7.5 making each first stage 15 million, 22.5 million (15 + 7.5) for a complete F9R and 52.5 million (3 * 15 + 7.5) for the F9H. It also means there's an overhead of 37.5 million for each launch going into range payments, pad rent, payload integration and company profits.
How much of that is for the hardware and how much goes to things like paying for the Air Force range tracking and rent on the pads though? There will be a fixed cost per launch that is independent of the number of first stages involved. Still sounds like a bit of a bargain mind you.
making throwaway rockets as efficiently as possible without the agenda of the space agencies or defence contractors
Military involvement as it was originally designed as a very large ICBM, but it's thought the Russian Proton takes a team of around 50 people just under a year to build. It's assembled horizontally (the first stage is put together from 7 components which are the largest size that will fit a standard Russian railway tunnel) when it reaches the launch site. All pad services run through a single set of umbilicals at the base of the first stage and the pre-launch checkout is highly automated. That's probably as cheap as you can get. Buying a Proton launch if you aren't Russian isn't that cheap as there's a lot of middle-men taking a cut.
It's the people needed to build, inspect and launch a rocket cost a large chunk of the money. The more of a particular model you can launch, the less the standing army adds to each one. Elon Musk has mentioned that during the stand-down they've got the first stage production rate to one every three weeks. Start adding in reflights of recovered stages and they could hit a launch a week which gets them to the point where they need another shift at the assembly and launch point.
You end up with a much bigger, and hence more expensive
Rocket cost only weakly scales with size, complexity affects it far more. This Falcon 9 had around 30% more capability than the baseline v1.1 model at the cost of a bunch of engine improvements and a few feet extra on the tanks. No significant added complexity, and an extra ring of aluminium welded in during manufacture.
Or not paying attention for the last couple of years.
As pure oxygen is toxic above 0.5 atmospheres, it seems unlikely it was both "pure" and "high pressure"
And you'd be wrong. The spacecraft cabin was pressurised to 16.7psi with pure oxygen, the idea being that during launch the pressure would be reduced to around 5psi when in space. The crew were fully suited and breathing from a different supply.
"That's the nearest asteroid flyby since 2006"
Ummm, no?
There has been at least one bigger and closer in November 2011, and at least a dozen have come inside the moons orbit since then. http://www.theregister.co.uk/2013/02/15/2012_de14_asteroid_fail/ for instance a day or two after Chelyabinsk.
I suspect Mr Davis had a lot less, erm, "guidance" for his little revival of a minor science fiction series that had been cancelled years before, and was better placed to resist the increased level of "advice" as it returned to being a flagship programme. Hopefully Stephen Moffat is managing to shake off some of the barnacles that attached when he took over. Scripts like Blink and The Girl In The Fireplace along with his work on Sherlock show he can produce excellent work when he's allowed to get on with it.
But what's with all the numbers ?
The pictures are from part of the KURS docking system (over on the right, 6 lines down "KYPC") giving distances, velocities and angles between the station and the Soyuz. eg bottom left quadrant gives the distance, 208m with a relative velocity of 0.1m/s in the first pic and 40m out closing at 0.14m/s in the second. If a manual docking is needed the crosshairs are lined up with a target beside the docking port on the station which gives a visual indication of whether you're on line and at the right angle.
It's actually got some clever stuff like bellows inside to make sure you can get the water back out again and sensors to tell how full it is so not just a tank.
According to an ex-shuttle worker commenting on http://spaceflightnow.com/2015/08/19/photos-water-tanks-removed-from-shuttle-for-new-use/ the manufacturer for these tanks went out of business and this is a lot easier than trying to source suitable new tanks.
" take the train if you want to nail 600 miles in a single trip."
Speed up main line electrification and bring back Motorail. Your self driving electric car takes you to the station, drops you off at the ticket hall, pootles round to the loading bay and hops on the train itself, recharges on the journey, and is outside waiting for you at the far end.
How to deal with changing platforms in a hurry and cars that decide to go to Aberdeen when their owners were heading to Cardiff are left as an exercise for the software engineering team...
It's one of the minor reasons for switching to Methane for the fuel. It's not hard to process the Martian atmosphere into Methane and Oxygen which you can use to refuel your lander for the trip back up. Takes power and time but saves a huge amount of payload lifted from Earth.
A tweet from Elon Musk suggested it was an over-pressure event in the second stage oxygen tank. So probably something like tank burst causing debris which took out the first stage.
At the press conference that has just finished Gwen Shotwell of SPaceX said she wasn't aware of the range safety being used. There were also comments that telemetry from the Dragon carried on after the event.
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