JerryZaza

JerryZaza

Joined on Aug 11, 2012

Comments

Total: 4, showing: 1 – 4
In reply to:

cleverinstigator: I'm sorry why not put up a few satellite relays in between so we can get some decent images of the planet why spend that much money on a mission that is 8 years behind in sensor technology. 2mp is a joke for landscape shots.

Well for starters, the Earth and Mars revolve around our Sun at different speeds. the Martian Year is about twice the length of Earth's. That is why the "Primary Mission" has to last 2 Years (Earth) or 1 complete season for Mars.
So the distance from Earth to Mars is constantly changing.
And as a result you can't place "repeaters" between Earth and Mars. The best we can do and NASA DID is to place some repeaters around Mars itself. Actually NASA has 2 and ESA will add a 3rd.

Direct link | Posted on Aug 11, 2012 at 17:25 UTC
In reply to:

prohidium: 250 megabits is roughly 31 megabytes of data over a 24 hour period. They must be using jpg compression to make it worth while. That is not very much data at all. It is about 2.9Kb per second or 2900 baud. That was the speed of data on earth in about 1986. I suspect the actual speed might be higher but there are probably some blackout periods through the day where the orbiting relays do not line up well and they can't transmit at full speed.

Uhm when they state an available bandwidth/day that takes into account any blackouts that happen during that day. And no there is no compression on data as someone as pointed out JPEG is a lossy compression algorithm i.e. You loose information with it the more you compress the more you loose. NASA has developed over the years algorithms that compress data without loss. But I would imagine that they are applied to the Data Stream itself, also the same algorithms need to cope with any errors that might occur during transmission. We are talking about receiving data from 300 million kilometers after all.

Direct link | Posted on Aug 11, 2012 at 17:15 UTC
In reply to:

SunflowerFly: The computer on board:
200MHz G3, 256MB RAM, 2GB SSD drive (yes, seriously), VxWorks OS.

Actually at the last press conference the Engineer for the software stated that it was a "120 Mhz MicroProcessor"
Which is not to be laughed at, you would be amazed what that machine can do if you write code for it in Assembler Language (most compact and efficient) or a well optimized C++ code compiler.
Without all the added junk and inherent inefficienties of an OS like Windows adds that processor is very powerful.

Direct link | Posted on Aug 11, 2012 at 17:07 UTC
In reply to:

aired: Very likely another fake landing. Black and white photos again? Low res photos? !!!Average person will associate low resolution and grinny and de colored photos as more authentic and real than vivid high resolution photos!!!

Black and white photos and videos can mask the fake artificial lights. In pro photography world one that can shoot and edit color professionally can do black and white easily. But not the case for black and white only photographer.

The light source that look too close to the subject can be identified

And of course the earth is flat and the Sun revolves around it. Gosh! never mind that any seriously minded Ham Radio operator can actually receive the signals sent back from Mars independently from NASA. http://www.uk.amsat.org/2578

Direct link | Posted on Aug 11, 2012 at 16:48 UTC
Total: 4, showing: 1 – 4