What is "Jaspreet" in non-pingrez?UlanBatori wrote:They need to send the Jaspreets.
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What is "Jaspreet" in non-pingrez?UlanBatori wrote:They need to send the Jaspreets.
If a working Jaspreet with the required structural integrity can be made, why would the comm design lag behind, hain ji? The whole body of Jaspreet can act like an omnidirectional atenna.UlanBatori wrote:Transmission to the Orbiter may be a slight problem, we haven't solved it yet.
As I was reading somewhere in the literature the final SNR (Signal to Noise ratio) was just 8 db or so and the antenna gain was >10 dB (perhaps 18 dB) for the designed bit rate. The post hard-landing radio tracking indicates faded but unambiguous carrier that could only come from the lander (as there are no other craft that is using that freq). The very fact that carrier can be detected (by synchronous detection in the digital radio receiver) indicates antenna pointing syndrome.somdev wrote:Vikram lander has directional high gain antenna which would not work if the orientation is not right ...but then again what about the low gain antenna on board for such critical situations?
AFAIRrecall electronics was radiation hardened. OTOH there is no concept of Temp hardening as almost everything is Silicon based semiconductor and at best Military/space rated parts operate upto 125deg C and junction temp of 150 deg C.prasannasimha wrote:While we talk of mobile hardware simple thing they are not radiation and delta T hardened enough -( remember even Chandrayaan 1's electronics got fried despite hardening to a particular level so they has to redesign)
You mean IMU gimble lock? As the gyros sensors are solidstate. But for that exact reason one always has one more axis ; ie 4 axis.prasannasimha wrote:Gyroscopes could have had a Gimbal lock
piezoelectric generator to charge a battery? it can keep uploading all the data after it comes to halt. it may not be able to move around though or can it? thre are some interesting materials that display PE effect - ceramics, polymers (from Wikipedia page)UlanBatori wrote:All point to the need for the Jaspreet. VTji, the whole point is to get rid of this dependence on legs, ... Of course once fuel is exhausted it dies: I can't see how to make it solar/thermally-powered while also being able to survive hard bounce.
two flips or a flip flop.UlanBatori wrote:What is 360 degree flip?
If you see the image during the landing the animation showing the position of the lander actually did a Vishnu chakra type of somersault 360 deg rotation back to its vertical position and righted itself (I immediately commented as to why it was doing such a flip) but there was a sharp [period of descent when it was pointing itself "head down" towards the moon. By that time it had a steep vertical height loss. So the control system tried to correct the landers position which was supposed to be straight up in the fine breaking phase(or whatever they were calling it)UlanBatori wrote:What is 360 degree flip?
Locomotion is the key advantage of the Jaspreet, compared to the honey-wagon Rovers/Chariots with their clunky wheels, transmissions etc. As long as fuel lasts, the ball can boost off the surface along a ballistic trajectory, and bounce along. May last only a day of hop-skip, but can cover a huge area. You can now trade off the fuel and nozzles cost against the savings by avoiding the legs, shock-absorbers, interior-carried rover, ramp, rover wheels, etc etc etc. Now that I think about it, that is a good amount of fuel.Vayutuvan wrote:piezoelectric generator to charge a battery? it can keep uploading all the data after it comes to halt. it may not be able to move around though or can it? thre are some interesting materials that display PE effect - ceramics, polymers (from Wikipedia page)UlanBatori wrote:All point to the need for the Jaspreet. VTji, the whole point is to get rid of this dependence on legs, ... Of course once fuel is exhausted it dies: I can't see how to make it solar/thermally-powered while also being able to survive hard bounce.
on second thought, I yield to Ramana. I understand why he wants to put a stop to this line of thinking. pranaam.ramana wrote:UB please don't encourage out of carton thinking.
What is the 4th axis? ( I thought, Einstein was the only guy, who believed in the 4th axis ).Haridas wrote:You mean IMU gimble lock? As the gyros sensors are solidstate. But for that exact reason one always has one more axis ; ie 4 axis.prasannasimha wrote:Gyroscopes could have had a Gimbal lock
A means to keep the 3 gimbles away from getting near lockin orientatuon.juvva wrote:What is the 4th axis? ( I thought, Einstein was the only guy, who believed in the 4th axis ).Haridas wrote: You mean IMU gimble lock? As the gyros sensors are solidstate. But for that exact reason one always has one more axis ; ie 4 axis.
Both CY2, and Nasa's LRO are near polar orbit.., LRO's next pass will be in October over the site in better lightning condition. CY2 will also pass through (about once a month) over the course of the year. (Per ISRO the orbiter is functional and it is scheduled to send back observations over the year..) More eyes in the sky better it is.ashbhee wrote:If ISRO has images of Vikram why not release it, why are they waiting for NASA to do it?
Then please desist from posting if noncontributoryUlanBatori wrote:This thread is now more repetitive than an orbit by the LRO. As long as nothing new is discussed v should b fine. Maybe post a few pics of the launch?
Just to give a sense, this is one picture from LRO ..( CY2 images will be similar too).. the circled part (and in real life, there were thousands such candidates) was suspected by some as possible Vikram.. One literally does that by comparing 'before' and 'after' pictures to see if there is anything new in the land-scape at the right point.Amber G. wrote:ashbhee wrote:If ISRO has images of Vikram why not release it, why are they waiting for NASA to do it?
For example, LRO's recent image - approximately 900 million illuminated pixels were examined for the target area (about 1km x 1 km) .. If I understand correctly each pixel is slightly bigger than a meter ([NASA/GSFC/Arizona State University has more details.).
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