Re: Travelling Wild West Show?
Yes, I remember something just like. I think I even have a photo of one of the gorillas. I found them scary at the time as a small child. Lots of shooting too.
16 posts • joined 21 May 2015
I am sad that Schiaparelli crashed as it seemed like an interesting mission. ESA needs to get to the bottom of this quickly as the next ExoMars mission is apparently using the same landing concept and software. The report on Ariane 5 V501 loss was good and thorough.
They should do the same thing here. Publish the details and let's learn from what went wrong.
Recommendation #2 from the Ariane report seems a good one:
R2 Prepare a test facility including as much real equipment as technically feasible, inject realistic input data, and perform complete, closed-loop, system testing. Complete simulations must take place before any mission. A high test coverage has to be obtained.
I know David Parker is a very competent engineer am sure he will drive this in the right direction.
You could tell it was really just a matter of time before SpaceX succeeded. They were so close a few times now. I am still mightily impressed by the physics and engineering involved. The live coverage was good too. Surely we need more of this kind of thing.
Congrats to everyone involved.
It's all about the base - apparently most of the mass is the bottom end after landing. I heard some hand-waving explanation about welding the feet to the deck afterwards. I seems more likely to me that they have some special fixtures that they put over the feet and tie down to hard points on the deck for the journey back. Wire stays - probably sensible to add once the structure is stabilised.
The german influence is showing here. Industrie 4.0 is talked about in manufacturing and academic circles. It does not have the same ring in English. I think Siemens and Bosch (both industrial automation companies) have been pushing it. It seems to me that WEF has been a bit of a yawn fest this year.
Perhaps without the protestors it's missing something. Most of the big pressure groups are giving it a rest this year. Public Eye on Davos said goodbye last year with a lifetime "achievement" award for Chevron.
I recently purchased a digital bat detector from Peersonic. It samples directly at 384 kHz with an ultrasonic microphone and you can listen to the sound slowed down by up to a factor of 20. It will write a sound file to an SD card and you can connect to a PC with USB to download the files. You can process them with a program like Audacity. It is a really cool gadget to have.
Since the bats near us are taking a well-earned winter rest I've been listening to other things. Jingly keys slowed down sound like really huge keys. Surprisingly, a nice source of ultrasound seems to be a fast running stream of water from a tap into a metal sink. I measured some fountains and they also had a peak around 30kHz.
That's right there will be an equilibrium reached for an object in space between the energy absorbed and the heat radiated to the background of space. For a gold surface facing the Sun in low earth orbit and insulated on the back this probably will not be high enough temperature to melt the gold. You can work out the temperatures roughly.
Heat energy radiated to space approx = area *5.67x10^-8* infrared emissivity * (temperature in Kelvin)^4 .
I've simplified the equation here by assuming the background is 0 Kelvin rather than 3 Kelvin.
5.67x10^-8 is approx. the Stefan-Boltzmann constant.
Solar heat input at Earth orbit say 1400 W/m^2
Gold solar absorptance 0.2 -> so 280 W absorbed per m^2
I worked out the temperature to be 705 Kelvin or 430 Celsius.
Gold has a low infrared emissivity - that means it won't lose much heat by radiation at the temperatures we are used to. In this case it is probably meant to keep the structure at a very uniform temperature, so that it does not distort too much. Distortion would affect the pointing accuracy to the next satellite.
Gold would also stop the surface corroding but there are better and cheaper ways of doing that. There are space qualified paints or other coatings.
Gold on its own would get rather hot in the sunlight as it absorbs light in the visible and ultraviolet but does not radiate much in the infrared. Usually there would be multiple layers of insulation or MLI blanket over the top of what you see in the picture to protect the system from the cold of space and from the Sun's heat.
Is there no market for a decent Star Wars space sim? I've been waiting for years for an updated version the original games. I liked that the missions and the ships' controls were quite complicated. I've read that the latest games (Battlefront) are a bit dissapointing in that respect.
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