* Posts by Highroads

16 posts • joined 21 May 2015

It's been 50 years since those damn dirty apes took the planet by storm


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.

'Data saturation' helped to crash the Schiaparelli Mars probe


Full disclosure required

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.

Hollywood offers Daniel Craig $150m to (slash wrists) play James Bond


Best Bond we never had.

Yes, I think Clive Owen would have been excellent. I would pick Chiwetel too but he is already, according to the rumours, possibly the best Dr. Who we never had.

Watch: SpaceX finally lands Falcon rocket on robo-barge in one piece

Thumb Up

Extremely impressive

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.


Re: pointy stick

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.

Dead Steve Jobs owed $174 by San Francisco parking ticket wardens


Cake I will survive

The little car reminds me of the video to Cake's I will survive.

Boeing's X-Wing 737 makes first flight


Re: infinite improvements

Like the verse by Lewis Fry Richardson

Big whirls have little whirls that feed on their velocity,

and little whirls have lesser whirls and so on to viscosity.

Davos 2016: It's now all about technology, but what actually happened?


Industrie 4.0

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.

Forget infrasound, now it's ultrasound that's making you ill (allegedly)


Bat detector fun

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.

Europe's satellite laser comms system set to shine


Re: buy why?

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.


Re: buy why?

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.

I have you now! Star Wars stocking fillers from another age


Bring back TIE fighter

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.

The ball's in your court, Bezos: Falcon 9 lands after launching satellites



Watched the video on Youtube this morning.

It's great. Big fireball comes down. Fire goes out. Smoke clears and then there is the rocket standing in the middle of the pad. Audience goes wild!

Congratulations to SpaceX!

Think Fortran, assembly language programming is boring and useless? Tell that to the NASA Voyager team


Sounds familiar...

Isn't this just the plot for "Space Cowboys?"

Mine is the XXL spacesuit.

Mystery object re-entering atmosphere may be Apollo booster


A hollowed-out Chuy-hirtsi perhaps?

US Air Force reveals what's inside its top-secret space plane, this time


Re: Only one Ion Engine?

"I understood they worked much better in multiples, usually in a twin arrangement."

I think it's an acronym. First use about 1977?


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