Bharat Rakshak

cy3 gallery (so far):

https://www.isro.gov.in/chandrayaan3_gallery.html

Especially for the audience who is familiar with night sky ....

As I post this message, Looking from the vantage point of Vikram:

Here is what stars look like, at the time I am posting this.. Enjoy...

Those who are familiar with star names in Hindi, or naxtra's .. I am naming them too (in Hindi)

You can see Venus, Sun, Earth ... since sun is quite bright, the other stars may not be visible .. (unless you block the sun )..

Enjoy!


( - By Amber G - - (I have put labels - using familiar naxtras etc - the are labeled by hand - it is near the naxtra -- I have used hindi star names for especially bright stars -- or brightest star in the naxtra -- )

Why is Venus so bright?. It's almost as bright as the Sun.

^^^

Rupesh wrote: ↑02 Sep 2023 00:52 Why is Venus so bright?. It's almost as bright as the Sun.

I was playing with the brightness ( theoretical value) so that I can print it out .. -- sun is much much brighter (with that in the sky all other stars will fade..).. The brightness you see for sun is is not sun but a magha naxtra's brightest's star (Regulus).... Sun is very close to that star when the positions were printed out. .. Remember it is "day" there, normally you don't see stars in the day, unless you block the sun very nicely.

(If you are curious, Sun there is about 600 billion times brighter than that bright Venus -- which itself is quite bright)

disha wrote: ↑01 Sep 2023 08:16 Since it also means, that Sun and not Earth is center of the Solar system (and stating that cost Galileo his freedom! and almost near death) and further, the solar system is just another of those solar systems in the Universe. And that is profound.

Atcually Giordano Bruno was burnt at the stake for proposing SOlar centered universe and stars being distant suns.

https://en.wikipedia.org/wiki/Giordano_Bruno

Giordano Bruno (/dʒɔːrˈdɑːnoʊ ˈbruːnoʊ/; Italian: [dʒorˈdaːno ˈbruːno]; Latin: Iordanus Brunus Nolanus; born Filippo Bruno, January or February 1548 – 17 February 1600) was an Italian philosopher, poet, cosmological theorist and esotericist.[4] He is known for his cosmological theories, which conceptually extended to include the then novel Copernican model. He proposed that the stars were distant suns surrounded by their own planets (exoplanets), and he raised the possibility that these planets might foster life of their own, a cosmological position known as cosmic pluralism. He also insisted that the universe is infinite and could have no center.

Wow... is this true?

https://twitter.com/isro/status/1697881823391711684

Chandrayaan-3 Mission:

Pragyan 100*

Meanwhile, over the Moon, Pragan Rover has traversed over 100 meters and continuing.

At the end of Aditya L1 launch, Dr Somnath said that within next 1 or 2 days, they'll start preparing the lander and rover to hibernate.

srin wrote: ↑02 Sep 2023 17:30 At the end of Aditya L1 launch, Dr Somnath said that within next 1 or 2 days, they'll start preparing the lander and rover to hibernate.

I thought we had 14 days of sunlight ?

Negotiating craters... U Turn from the edge of the crater ..... Walking on the edge of the crater......

Pragyan must have been trained on Indian .no-roads'.

India should name the circle as Pragyan circle whose center is ShivShakti point.

Something seems off in that image. If the scale is 50m X 50m, and if that represents the entire rectangle (square), then the distance traveled, as shown, seems to be about the width of the image - should be around 50m. Unless the rover retraced that entire path back?

srin wrote: ↑02 Sep 2023 17:30 At the end of Aditya L1 launch, Dr Somnath said that within next 1 or 2 days, they'll start preparing the lander and rover to hibernate.

Yeah, they'll definitely be going to sleep when the Sun goes down. ISRO has a contract with BARC where the latter is developing RTGs (Radioisotope Thermoelectric Generators) and RHUs (Radioisotope Heating Units) for them. These nuclear decay power sources will enable continuous power and heating for Indian spacecraft, including future rovers, etc. Chinese and Russians have already used them on the Moon (the recently crashed Luna-25 was nuclear-powered).

I've read some optimistic claims that the lander & rover may be able to survive the lunar night, but I really wouldn't bet on that.

I still hope they do survive, because I would've liked to see them take a picture of Earth (especially if our hardware is in the same shot.)
I especially would've liked to see a picture of Indian flag and Earth in the same shot.
(We can see from pictures of our rover tracks, that our Asoka Lions emblem and ISRO logo aren't showing up at all. Why would anyone expect that if wheels are rotating and smearing the dirt?)

https://twitter.com/isro/status/1698010732128764164

Chandrayaan-3 Mission:
The Rover completed its assignments.

It is now safely parked and set into Sleep mode.
APXS and LIBS payloads are turned off.
Data from these payloads is transmitted to the Earth via the Lander.

Currently, the battery is fully charged.
The solar panel is oriented to receive the light at the next sunrise expected on September 22, 2023.
The receiver is kept on.

Hoping for a successful awakening for another set of assignments!
Else, it will forever stay there as India's lunar ambassador.

sudarshan wrote: ↑02 Sep 2023 07:37 Wow... is this true?

[youtube RWGFDVK69Zw plan to nuke the moon ]

I knew Carl Sagan very well (over 25 years) but I have not heard of it before. He did not talk about it and in none of the books/articles I have seen, he mentioned it . Yet the items presented in the video are basically correct, and main-stream newspapers did have articles. So the video is quite well and well produced.
Carl Sagan who was student of Kuiper (also worked with Urey, Gamow, Chandrasekhar) has written *several* books and articles -- both for scientists and popular. (We both are physicists and have a great interest in astronomy/astrophysics). I highly recommend his books and extremely popular COSMOS series. (If you have not seen it, it is as good as it gets for any student for astronomy). Voyager record, which has greetings in many languages , Greetings in all Indian languages (including Rajasthani were recorded by a few of Indian grad students in Cornell. )..

(In younger days he did have top/secret clearance but later he never worked for military etc .. he was quite against using science for anything other than peace ... and had great relationship with international scientists)

ISRO has put the rover to sleep in just 10 earth days instead of full 14 earth days of a lunar day. Any idea why did they stop just in 10 days.

Yeah, they'll definitely be going to sleep when the Sun goes down. ISRO has a contract with BARC where the latter is developing RTGs (Radioisotope Thermoelectric Generators) and RHUs (Radioisotope Heating Units) for them. These nuclear decay power sources will enable continuous power and heating for Indian spacecraft, including future rovers, etc. Chinese and Russians have already used them on the Moon (the recently crashed Luna-25 was nuclear-powered).

Just for perspective - As I posted before: RHU is not that challenging ..

In 1970's or so they were even used in medical devices (like pacemakers). Over time, advancements in battery technology led to the development of smaller, longer-lasting, and safer power sources for medical devices. Lithium batteries, in particular, became widely used in pacemakers and other implantable medical devices due to their high energy density and safety profile. (As safer and more reliable battery technologies became available, the use of Plutonium-238 RHUs for medical devices like pacemakers was discontinued).

These units are less complex then RTG, -- One of the key advantages of RHUs is their longevity. They can continue to provide heat/power for decades, which is essential for missions to the outer solar system or deep space, where solar panels become less effective due to reduced sunlight.

RHUs have been used in many notable missions, including the Mars rovers (Spirit, Opportunity, Curiosity), the Voyager spacecraft, and the New Horizons mission to Pluto, among others.

--
RTGs are used to generate electrical power for spacecraft, while RHUs are used to provide thermal heat for temperature control in space missions. Both devices rely on the heat produced by the radioactive decay of isotopes like Plutonium-238 (or Po210), but they serve different purposes in the context of space exploration.

IOW: The main output of an RTG is electrical power, which is used to operate spacecraft systems and instruments.
While: The main output of an RHU is thermal heat, which is used to maintain the temperature of critical components and systems on spacecraft.

For safety and shielding:

RTGs are designed with multiple layers of containment to prevent the release of radioactive material in the event of a launch failure. Safety protocols are strictly followed to minimize the risk to the environment and human health.
:RHUs are also designed with safety in mind, but they are generally smaller and have a lower radioactive content compared to RTGs. They are used for less power-demanding applications. (Typically few grams of Pu-288 all shielded nicely in Iridium type casting etc)

akashganga wrote: ↑03 Sep 2023 00:44 ISRO has put the rover to sleep in just 10 earth days instead of full 14 earth days of a lunar day. Any idea why did they stop just in 10 days.

Apparently It is well planned in advance..Making sure, there in enough time to run all last minute tests..fully charge battery and making sure solar panels are in right direction when the new dawn arrives --(after doing that, tickle charge the batteries again. after all possible shielding/positioning has been done).. Sun is quite low at present..so power generation is low too... ityadi.. ityadi...

akashganga wrote: ↑03 Sep 2023 00:44 ISRO has put the rover to sleep in just 10 earth days instead of full 14 earth days of a lunar day. Any idea why did they stop just in 10 days.

Chandrayaan-3: Mission goals met, Vikram, Pragyan to be put to sleep Sunday

Chandrayaan-3 project director P Veeramuthuvel told to TOI in an exclusive interaction.

“A full lunar day is from 0° Sun elevation angle to 0° angle. But the mission is not designed like that. For landing, the angle requirement was 6-9° elevation and we managed to land when elevation was 8.75°. For operations, we need a minimum of 6° elevation angle because our cameras and other systems are characterised for that. It's also for solar panels to remain optimal. Once it goes below 6° elevation, there’s a long shadow,” he said.

While there is a grace period for operations to continue, Isro is opting to begin the process of enabling sleep mode earlier than that. “We want to enable the sleep sequence before this grace period to avoid any last-minute challenges or hurdles. We want the lander and rover to enter the sleep mode as flawlessly as they’ve done everything else so far,” Veeramuthuvel said.

Currently, the battery is fully charged and the solar panel is oriented to receive the light at the next sunrise expected on September 22, 2023. The receiver is kept on.
“Hoping for a successful awakening for another set of assignments! Else, it will forever stay there as India's lunar ambassador,”

ChangE 4 recorded a night time temperature of -190C on the far side of the moon. For CY3 and Pragyan the challenge to survive the lunar night without power will be pretty tough. Unprecedented if ISRO succeeds in this endeavor.

https://www.space.com/43192-china-farsi ... night.html

http://www.leonarddavid.com/chinas-chan ... survivors/

Amber G. wrote: ↑03 Sep 2023 00:56 In 1970's or so they were even used in medical devices (like pacemakers). Over time, advancements in battery technology led to the development of smaller, longer-lasting, and safer power sources for medical devices. Lithium batteries, in particular, became widely used in pacemakers and other implantable medical devices due to their high energy density and safety profile. (As safer and more reliable battery technologies became available, the use of Plutonium-238 RHUs for medical devices like pacemakers was discontinued).

What do you think about Beta-Batteries? They use radioactive beta-decay for trickle-charging or very low-power electronics. Do you think these will prove to be useful and worth developing for space applications?

sanman wrote: ↑03 Sep 2023 08:58

Amber G. wrote: ↑03 Sep 2023 00:56 In 1970's or so they were even used in medical devices (like pacemakers). Over time, advancements in battery technology led to the development of smaller, longer-lasting, and safer power sources for medical devices. Lithium batteries, in particular, became widely used in pacemakers and other implantable medical devices due to their high energy density and safety profile. (As safer and more reliable battery technologies became available, the use of Plutonium-238 RHUs for medical devices like pacemakers was discontinued).

What do you think about Beta-Batteries? They use radioactive beta-decay for trickle-charging or very low-power electronics. Do you think these will prove to be useful and worth developing for space applications?

Don't know much about Beta - Batteries. But FWIW, here - for CY3, main issue is survival of electronics (and batteries/solar cells etc) after long lunar night of low temperature. Small RHU can solve the problem, and it is not challenging (in terms of technical matter) for India at all. Low tech alternative may exist. We will see, if the new, hardened electronics survive. (We could also insulate - lunar soil is good for that as Vikram discovered -- perhaps to store some day baked rocks in well insulated cave/shelter )

Unfortunately most of Indian Newspapers (like this one from Hindu) confuses the issues by calling these devices "nuclear-engines for rockets".

Nothing official, I have seen in any of the news papers, but I do know, RHU of 1 watt (and 5W RTG) could be available easily now (or near future) if they want... BARC has sent tender for 100 W RTG ityadi..




Here is a slide from an old lecture (given around 9 months ago) by Dr. Somanath from my saved stuff..

5W Radioisotope Thermoelectric Generator (RTG) to be developed (BARC collaboration). (relevant)
1W Radioisotope Heating Unit (RHU) developed, flight trial soon.

(This is why, when someone reported 'rumors of ' 1W RHU' --I said, that rumor can have some basis)

The iconic and powerful voice behind #isro rocket launch countdowns, has faded away for eternity...Smt. Valarmathi passed away at a Chennai hospital on Saturday evening, after a heart attack..
She was last heard counting down on July 14th for #chandrayaan3 LVM3

Om Shanti.

Appropriately, "Valarmathi" in Tamil means "Growing Moon." I.e., the moon waxing in brightness from Amavasai to Pournami (Tamil words for Amavasya and Poornima). She was there while the rover was frolicking in the waxing moon, and then passed away when the moon started waning.

Om Shanti to this naari mani (gem of a lady)

There has been some discussion about remaining day light near Vikram:

. Sun is quite low at present..so power generation is low too... ityadi.. ityadi...

“ A full lunar day is from 0° Sun elevation angle to 0° angle. But the mission is not designed like that. For landing, the angle requirement was 6-9° elevation and we managed to land when elevation was 8.75°. For operations, we need a minimum of 6° elevation angle because our cameras and other systems are characterised for that. It's also for solar panels to remain optimal. Once it goes below 6° elevation, there’s a long shadow,..”

Currently, the battery is fully charged and the solar panel is oriented to receive the light at the next sunrise

While we all wait for the dawn in September at Shivshakti point ..

Just for fun, and knowledge here are few questions for those who are not annoyed by math:

Assuming it is now: September 4, 2023 6:30 AM (IST) (= 2023/09/04 01:00 UTC)
Q1 - What is the elevation of Sun at Vikram Now?
Q2 - When will sun set ? ( Date, Time in Hours, Minutes)
Q3 - When will be the first rays of sun will hit Vikram ?
Q4 - When will the elevation reach 6 degree?
Q5 - When will be the next 'noon' (Highest elevation of the Sun in the vicinity)?
Q6 - When will be the next dawn (or noon) in October?
Q7 - What is the length of the "day" (Noon in September to Noon in October.

And a 3 more (or less) challenging questions:
Q8 Where and when can one see Brightest star Sirius and second brightest star Canopus (There position on a given date or time of their rise or setting)
Q9 - How long does it take for these stars to make a full cycle (time it takes that it repeats it's position in the sky.
Q10 - What planets are visible in the night sky ?

----
We all know the location is at of Shivshakit point is (-69.373°, 32.319° E )
We also know the periods of sun/moon/earth.. (See posts in this dhaga)
Rest is simple math (Knowledge of suryasiddhant may help but not necessary )

----
Would like the values as precise as you can get/estimate/calculate.. For time, date/hours/minutes , for angle: degrees. will be okay. .. Use of calculators is, of course, okay.

---
Give your values here in this thread. Curious to see the values posted here -- Discussing the math can be done in the math dhaga..

Amber G. wrote: ↑04 Sep 2023 00:20 The iconic and powerful voice behind #isro rocket launch countdowns, has faded away for eternity...Smt. Valarmathi passed away at a Chennai hospital on Saturday evening, after a heart attack..

OMG. She was not there for the Aditya mission. We have got so used to her over the years. I am saddened. Om Shanti.

An article w/o the usual India bashing for a change from the Sydney Morning Herald and The Age,

This is an AI generated summary. There may be inaccuracies.

00:00:00 - 00:10:00
The moon is set to become a bustling hub of activity as countries and private companies invest in lunar exploration. The discovery of water on the moon's South Pole has sparked interest in its potential for sustaining human life and serving as a gateway for interplanetary exploration. Water is seen as a key enabling element for generating breathable air and rocket fuel, making the moon a potential launch point for missions to Mars. India's successful moon landing has elevated its stature and provided an economic advantage, while Russia's moon crash reflects a loss of national pride. An intense space race, particularly between the US and China, is underway to secure strategic positions on the moon, which could provide advantages in future wars involving attacks on satellites and communication systems. With hundreds of public and private lunar missions planned in the next decade, countries like Australia are also seeking to join the space race.

00:00:00 In this section, the transcript discusses the significance of India's successful landing on the moon, highlighting the difficulty of landing on the lunar surface and the importance of this achievement. The South Pole of the moon is a target for landing missions due to the detection of water and potential for sustaining human life, as well as serving as a gateway for interplanetary exploration. The presence of water on the moon opens up possibilities for generating breathable air and using hydrogen as rocket fuel, making the moon a potential launch point for missions to Mars. This discovery is reshaping the geopolitical order and sparking a new space race among countries.

00:05:00 In this section, the speaker discusses how the moon is becoming a busy place with various countries and private companies showing interest and investing in lunar exploration. There are plans for ships from Earth to dock with a space station on the moon, refuel, and continue into deeper space. Water is seen as an enabling and empowering element in these plans. The speaker also explains how India's successful moon landing positively impacts the country's stature on Earth, giving them an economic advantage and enhancing their national status. On the other hand, Russia's moon crash reflects a loss of greatness and national pride for the country. The speaker notes that the current race to space represents a new confrontation between the US and China, as well as other countries positioning themselves on the moon.

00:10:00 In this section, the speaker discusses the strategic advantage that owning key positions in space, particularly on the moon, can provide. It is anticipated that future wars between major powers will involve attacks on satellites and communication systems, which are critical for warfighting. Therefore, controlling space could give one an advantage on Earth. This is why there is a rush for real estate on the moon, with more than 400 public and private lunar missions planned between 2022 and 2032. The fact that India achieved a lunar landing milestone on a shoestring budget has impressed the world and could encourage other countries, including Australia, to join the space race. India's success is drawing in other countries as participants and competitors, and Australia is seeking to connect its own space agency with the lunar exploration world.

Vikram soft-landed again! https://twitter.com/isro/status/1698570 ... 5l6mg&s=19

Did we know this was planned? Wow! What a nice surprise.

Yes a surprise indeed !!! now if both wakeup and if pragyaan can drive in, it can theoretically take off and go to another place, SS-2

Dumal wrote: ↑04 Sep 2023 11:33 Vikram soft-landed again!

Awesome. Like PS4 stage being employed after burnout as POEM (PSLV Orbital Experimental Module). Opens up other exciting opportunities and developmental efforts.

Dumal wrote: ↑04 Sep 2023 11:33 Vikram soft-landed again! https://twitter.com/isro/status/1698570 ... 5l6mg&s=19

Did we know this was planned? Wow! What a nice surprise.

Its indeed a welcome surprise.
Was able to lift up by 40 cm.
Will give useful insight for thrust required for sample return missions.
Also maybe the heat of the engines can be used to warm the interior a bit for the 14 day lunar night.

Dumal wrote: ↑04 Sep 2023 11:33 Vikram soft-landed again! https://twitter.com/isro/status/1698570 ... 5l6mg&s=19

Did we know this was planned? Wow! What a nice surprise.

And one person who monitors doppler frequencies asked:

Did it occur at ~2023-09-03T13:00 UTC yesterday?

Anyway here are post hop and pre hop pictures:

NASA's Surveyor 6 also similarly did another short hop later after landing. back in 1967:

https://en.wikipedia.org/wiki/Surveyor_6


Impressive that India has also done so on its first Moon-landing.
After all, plenty of fuel was left after Vikram's original landing, which was very efficient and flawless.

I wonder if one day, this hydrazine fuel could even be used to help power the lander and keep it alive/warm through a lunar night?
Like as a fuel cell, perhaps?

Per my calculations, sun is going to set at 18:09 (UTC) - in about 6 hours of this posting...



When the last rays of the sun will fall on Vikram before the new dawn... Better get ready for bed ... fully charged .. Happy dreams...

Vikram Lander is set into sleep mode around 08:00 Hrs. IST today (09/04

Prior to that, in-situ experiments by ChaSTE, RAMBHA-LP and ILSA payloads are performed at the new location. The data collected is received at the Earth.
Payloads are now switched off.
Lander receivers are kept ON.

Vikram will fall asleep next to Pragyan once the solar power is depleted and the battery is drained. Hoping for their awakening, around September 22, 2023.

BTW: This answers Q2 of my questions -- see if it agrees with your answer..

Dumal wrote: ↑04 Sep 2023 11:33 Vikram soft-landed again! https://twitter.com/isro/status/1698570 ... 5l6mg&s=19

Did we know this was planned? Wow! What a nice surprise.

looks like considerable dust was kicked up, but it seemed to settle down quiet fast.
or was it mostly thruster fumes and litlle dust ?

Dumal wrote: ↑04 Sep 2023 11:33 Vikram soft-landed again! https://twitter.com/isro/status/1698570 ... 5l6mg&s=19

Nice surprise ! I guess isro was playing with house money. They must have had a good idea this would succeed. But even otherwise, the mission was at the nominal end, despite the potential re-awakening on Sep 2022. After all, the rover only communicates with the lander, so the risk of upset must have been calculated to be minimal. And they got a new set of lander experiment data out of it, too !

I wonder if the slight repositioning helped with slight inclination/orientation to sun or earth..

The pics look nice !

And @calculating thrust to lift off from the moon - I doubt that this was particularly relevant.. for the actual calculations..

did not know that the ramp could be folded back and the science payloads pulled up back in.

what a detailed far sighted design !!!! and a very robust hardware !!!!

arvin wrote: ↑04 Sep 2023 13:10

Dumal wrote: ↑04 Sep 2023 11:33 Vikram soft-landed again! https://twitter.com/isro/status/1698570 ... 5l6mg&s=19

Did we know this was planned? Wow! What a nice surprise.

Its indeed a welcome surprise.
Was able to lift up by 40 cm.
Will give useful insight for thrust required for sample return missions.
Also maybe the heat of the engines can be used to warm the interior a bit for the 14 day lunar night.

m
Not sure if the rover roved back to the womb of lander before this soft landing. Chance of working is 50% after the lunar night. (Mission is already 100% success).

1) What if we fire this for 10 seconds every day(not the propulsion) but sending power internally.
2) May be in next mission - Invent an adapter for Rover to get energy from lander during winter days.

Infact, whatever we are doing is a new avenue from here on. Possibilities, possibilities everywhere.