Chandrayan-2 Mission

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Re: Chandrayan-2 Mission

Postby UlanBatori » 11 Oct 2019 02:28

Hasn't the sun come up?

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Re: Chandrayan-2 Mission

Postby SSSalvi » 11 Oct 2019 06:49

^^^
Sun has risen.. CH2 Orbiter passed over near Landing site on 9th,10th and also today.
But ISRO is MouthShut.

Irony is , We will definitely see coverage of area in public space through NASA LRO around 15th,16th,17th.

BTW what purpose will the image of a debris will serve?

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Re: Chandrayan-2 Mission

Postby UlanBatori » 11 Oct 2019 06:57

NDTV will publish it, they always like to publish the most gory images after disasters and terror attacks with no consideration for victims' relatives. :)

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Re: Chandrayan-2 Mission

Postby sajaym » 11 Oct 2019 10:18

SSSalvi wrote:BTW what purpose will the image of a debris will serve?


If like the earlier claims, the lander is in one piece and lying on its side then it is a 'soft landing' compared to landers from some other countries which just added another crater to the moon. If ours is in one piece...we've 'Soft landed' as we had claimed. Period 8) .

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Re: Chandrayan-2 Mission

Postby Amber G. » 11 Oct 2019 22:06

Vayutuvan wrote:
Amber G. wrote:- CLASS did just that, measuring a sharp increase in particles that ISRO has identified as electrons.. Initial data but I think it is exciting as we get more data about their spectrum etc. Considering that CY2 is going to spend a lot of time this may be important data for us.


What is the significance? in layman's language if you please.

Some basics (and also some exciting new news in the second part )

- CY2 has two top notch x-ray related equipments. CLASS ( CY2 Large Area Soft X-ray Spectrometer) and XSM ( Solar X-ray Monitor).
- They, among other things, study solar flares (strong source of X-rays).
- These x-rays, are like "flash bulbs" which "illuminates" moon surface. This prompts the elements to absorb these X-rays and emit a unique spectrum of light based on which element it is. These "secondary X-ray emissions" can be read by Chandrayaan 2's CLASS instrument. This can identify minerals on the moon's surface. And can make a detailed mineralogical map of the moon. (This can identify even elements like iron -- and with luck Vikram's elements)
- Moon, does not have a magnetic core (like spinning earth) and no atmosphere, hence solar wind reaches the surface without being weakened - on earth we are safe from that solar wind.

*** Apart from studying moon, these instruments also are useful is studying solar wind -- as we do on earth based sats..
(And this is what was my previous post was about)

- Similar instruments on earth's orbit, study earth's magnetic sphere by effects of solar wind. Since satellite communications, GPS accuracies etc depend on effects of solar flares, we need good data for this.
- CY2 is not in earth's orbit and normally outside geotail but about 6 days it is in the shadow, so these experiments and data are useful. (This is what I was mentioning before.. more data taken over years will be very good)
- CLASS was able to do this study and results are good.
(From ISRO Image)
Image

****
XSM meanwhile has also observed solar flare. ISRO's said that CY2 has got its first taste of a solar flare —
an important requirement for the spacecraft to study what the Moon's surface is made up of. ISRO has shared data that the orbiter's Solar X-ray Monitor collected on the flare.

At this time, solar activity is minimum but solar flares are kind of random.

This solar flare will help studying the moon's surface by CLASS..

Here is the ISRO article for more details:

Solar flare observed by the Solar X-ray Monitor on Chandrayaan-2
Image

Many violent phenomena continuously keep occurring on surface of the Sun and its atmosphere known as the corona. This solar activity follows an eleven-year cycle, which means, it goes through its 'solar maxima' and 'solar minima' once every eleven years. While the cumulative emission of solar X-rays emitted over a year varies with the solar cycle, these are often punctuated with extremely large x-ray intensity variations over very short periods, few minutes to hours. Such episodes are known as solar flares.

Chandrayaan-2 orbiter utilizes X-rays emitted by the Sun in a clever way to study elements on the lunar surface. Solar X-rays excite atoms of constituent elements on the lunar surface. These atoms when de-excited emit their characteristic X-rays (a fingerprint of each atom). By detecting these characteristic X-rays, it becomes possible to identify various major elements of the lunar surface. However, in order to determine their concentration, it is essential to have simultaneous knowledge of the incident solar X-ray spectrum.

The Chandrayaan-2 orbiter carries two instruments, Chandrayaan 2 Large Area Soft X-ray Spectrometer (CLASS) and Solar X-ray Monitor (XSM), to measure the lunar elemental composition using this technique. Here, the CLASS payload detects the characteristic lines from the lunar surface and the XSM payload simultaneously measures the solar X-ray spectrum.

Currently, the solar cycle is heading towards minima and the Sun has been extremely quiet for past few months. On 30th September 2019 00:00 UTC - 1st October 2019 23:59 UTC, a series of small flares were observed by XSM.


Hope this is helpful.

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Re: Chandrayan-2 Mission

Postby Amber G. » 12 Oct 2019 01:43

ramana wrote:AmberG, i as listening to NPR about Lunar environment and how its bombarded with cosmic rays and has all sorts of particles emanating from the lunar surface This was a few weeks back and my memory could be wrong.

So are these X-Ray florescence a bye-product of that?

Yes, previous post has more details. Cosmic rays, in general, has higher energy (up to GeV), all sorts of ions (all the way to Uranium) and gamma-rays (higher energy than x-rays). Solar flares produces most energies in KeV range, x-rays, electrons/protons/alpha particles/some ions etc.
(Cosmic rays has higher energy, say for each photon, but solar flare has more photons and thus much more flux)

As moon has no atmosphere and little magnetic field, this radiation hits harder on Moon than on earth. And yes the x-ray florescence is produced by moon surface - elements producing their characteristic spectra in X-rays, when hit by solar/cosmic radiation which can be analyzed by CLASS.

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Re: Chandrayan-2 Mission

Postby Amber G. » 12 Oct 2019 02:21

SSSalvi wrote:^^^
Sun has risen.. CH2 Orbiter passed over near Landing site on 9th,10th and also today.
But ISRO is MouthShut.

Irony is , We will definitely see coverage of area in public space through NASA LRO around 15th,16th,17th.

ISRO released pictures of the Moon's south polar region as seen by the Chandrayaan-2 orbiter and were posted here in BRF. These pictures are roughly 300 kilometers away from where the Vikram lander crashed on the surface. As of yet, AFAIK no public images of the crash site have been released by ISRO. LRO's data/pictures, per its policy, are public.

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Re: Chandrayan-2 Mission

Postby Amber G. » 14 Oct 2019 23:00

NASA's LRO imaging of Vikram's Landing place is quite ideal - shorter shadows and good lighting.
****

Meanwhile there is quite a bit of news coverage about CY2's XSM's data - Not only that the equipment is working fine but its efficiency and sensitivity is unmatched - much better than NASA's GOES-15 satellite, which is considered the current standard for reading Solar X-rays.

These readings are quite interesting - scientifically speaking - to provide insights into various processes on the Sun.

As posted here, and ISRO's tweets - between September 30 and October 1, a series of small solar flares were observed. The Sun has been relatively quiet in recent months, which is why the recent activity is of interest to astronomers. The XSM—which along with the Chandrayaan 2 Large Area Soft X-ray Spectrometer (CLASS) aims to use Solar X-rays to study the composition of the Moon's surface—detected the X-rays emitted in the flare.

ISRO said that the readings, due to "the large angle between Sun, lunar surface and Chandrayaan-2"" (close to 90 degrees against desirable close to zero), are not that useful to study the moon's surface (using CLASS) but XSM did detect much finer data than GOES-15

What was unique about XSM's observation is that it detected more subtle intensity variations than the GOES-15 satellite. It was also able to measure the X-ray spectrum with the highest energy resolution of a broadband solar X-ray spectrometer, over short intervals of 1 second.

I posted that comparison in my previous post: Here is is again.
Image

****
Here is what that solar flare may have looked like up close (Image Credit NASA - Just a stock picture of a typical solar flare :) )
Image

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Re: Chandrayan-2 Mission

Postby Vayutuvan » 15 Oct 2019 05:33

Amber G. wrote:...
Here is what that solar flare may have looked like up close (Image Credit NASA - Just a stock picture of a typical solar flare :) )
[img...]https://pbs.twimg.com/media/EGlB8iUUcAAid-p?format=jpg&name=small[/img]


From surface to the top tip, it is almost as tall as or maybe even taller than the radius of the Sun. Wow :eek:

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Re: Chandrayan-2 Mission

Postby Amber G. » 15 Oct 2019 09:14

BTW, if one is interested looking at detailed map of the moon - and zoom it to any location up to very high resolution from LRO .. a good resource is here: https://quickmap.lroc.asu.edu

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Re: Chandrayan-2 Mission

Postby sanjaykumar » 15 Oct 2019 10:42

The XSM data are much higher resolution than Goes but how does that add to solar structure or dynamics models?

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Re: Chandrayan-2 Mission

Postby Amber G. » 15 Oct 2019 21:37

Thought I will put a picture of Moon in X-ray spectrum.. (Seen from earth - an old photo)

Looking at the Moon in X-ray spectrum .. As seen in X-rays against the cosmic background, the Moon's illuminated (bright) and non-illuminated portions (dark) are clearly visible. This X-ray image taken by ROSAT. The X-rays, like almost all wavelengths of light, arise mostly from reflected emission from the Sun. (Photo Credit - NASA)
Image

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Re: Chandrayan-2 Mission

Postby Amber G. » 15 Oct 2019 21:57

For reference here is a map of the moon - projected from south pole.

I used the previously mentioned tools to generate the current map of the area of the moon (1 Pix about 2Km) around the Vikram's landing. (About (70.8 S, 23.5 E). Green dots is LRO sat orbit and the lighting condition is what is at present.


Image

If my understanding of url and img tags in brf is correct -- It might work - you may click on the image above to manipulate the zoom etc..

Edited Later: Yes it works... you can zoom in, change settings, time , etc..Actually very nice.

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Re: Chandrayan-2 Mission

Postby Amber G. » 17 Oct 2019 21:00

Finally some nice picture from CY2's IIRS -- See the first illuminated image of the lunar surface acquired by IIRS.
IIRS is designed to measure reflected sunlight from the lunar surface in narrow and contiguous spectral channels.)
Image

More at: https://www.isro.gov.in/update/17-oct-2019/chandrayaan-2-begins-spectroscopic-studies-of-lunar-surface
>>>
Preliminary analysis suggests that IIRS could successfully measure the variations in the reflected solar radiation that bounces off the lunar surface from different kinds of surface types, namely, crater central peaks (e.g., Stebbins), crater floors (e.g., Stebbins and Sommerfield), very fresh reworked ejecta associated with small craterlets within the crater floor of a large crater (e.g., Sommerfield) and also the sun-illuminated inner rims of craters (e.g., Kirkwood). The variations in the spectral radiance are primarily due to the mineralogical/compositional variations that exist in the lunar surface and also due to the effect of space weathering. More detailed analysis that follows, is expected to yield important results on the heterogeneity of lunar surface composition.

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Re: Chandrayan-2 Mission

Postby Amber G. » 17 Oct 2019 21:13

^^^ The main objective of IIRS is to understand the origin and evolution of the Moon in a geologic context by mapping the lunar surface mineral and volatile composition using signatures in the reflected solar spectrum.
Image
Image

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Re: Chandrayan-2 Mission

Postby Kanson » 17 Oct 2019 21:35

Any description/ info on the last pic?

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Re: Chandrayan-2 Mission

Postby Amber G. » 17 Oct 2019 21:37

Meanwhile about NASA's LRO pass over Vikram's landing site:
They say the lighting condition was good. Shadows are shorter. They are doing "rigorous" search (before/after comparison of millions of pictures). Probably take a few more days before lot of pictures come out in the newspapers.

What is the most "official" coordinates of Vikram's resting place? (Has ISRO published the coordinates where it said it saw it in thermal imaging). I haven't been able to see it a ISRO site.

For record, this the approximate area, as posted before. The image is taken by LROC - before Vikram's landing).
Image

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Re: Chandrayan-2 Mission

Postby ramana » 17 Oct 2019 22:10

AmberG, Any legend to the colors of the X-Ray map?

Also if the X-Rays are generated by reflections of Sun's rays, that is lots of high energy radiation!!!

What atomic reactions generate such high energy X-Rays?
Are these reflected rays like fission going on or just being bounced off the surface?

Thank nature for providing the atmosphere on Earth for Life to survive.

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Re: Chandrayan-2 Mission

Postby Amber G. » 18 Oct 2019 01:16

Kanson wrote:Any description/ info on the last pic?

Kanson - These pictures are few which I saved before. To be clear, these are *not* from Chandrayaan's IIRS but are from NASA's data (which are available). I can put more details, when I see my notes but the last picture (with phases of moon) was, I believe - will check and correct if need be - is from NASA/JPL's NIMS (Near Earth Mapping Spectrometer). Kind of old picture. (Can do a image search on nasa.gov site)
Added later:
More: for the pictures:
>>>
Earth is toward the left, and the lunar north pole is near the terminator, upper right. The dark regions to left and below in the black-and-white image at upper left, are lunar Maria, including Mare Imbrium at upper left, Serenitatis and Tranquillitatis, lower left center, and the circular basin to the right is Crisium. The bright areas ringing Crisium and dominating the center of the images are the heavily cratered and mountainous lunar highlands. The black-and-white image used infrared wavelengths just beyond the visible deep red. The false-color map images (upper right and lower right) show the relative strength of silicate-rock absorption of near-infrared sunlight, at about 1-micron wavelength. Blue areas show stronger absorption and generally indicate materials with more pyroxene and olivine (iron-bearing silicate materials), while yellow indicates less absorption, due to original compositional variations. In young fresh craters, absorptions are also stronger due to the absence of meteorite-impact effects. Outlines of previously defined geological units are superimposed in the lower right image. Note correlation with the Maria/highlands features in the black-and-white image. The preliminary mineralogical map at lower left uses infrared band shape and intensity to visualize variations in pyroxene and olivine. Blue is related to low-calcium pyroxene, while green and red indicate high calcium and the iron/magnesium content of pyroxene, as well as olivine.

>>>

The first picture, again I believe, is from from NASA's LROC. I like the colors because it helps us in visualization. -- They suspect a huge massive iron deposit around the center of blue region (The picture, if I remember correctly is South Pole Aitken basin area)

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Re: Chandrayan-2 Mission

Postby Amber G. » 18 Oct 2019 02:08

ramana wrote:AmberG, Any legend to the colors of the X-Ray map?

Also if the X-Rays are generated by reflections of Sun's rays, that is lots of high energy radiation!!!

What atomic reactions generate such high energy X-Rays?
Are these reflected rays like fission going on or just being bounced off the surface?

Thank nature for providing the atmosphere on Earth for Life to survive.


The X-ray picture is from "An Introduction to X-ray Astronomy" presentation. You can get legend and much more detail from here:
ttps://heasarc.gsfc.nasa.gov/docs/xrayschool-2005/talks/arnaud_intro.pdf

You may already know but short answers to your query -
- Sun radiates EM radiation, like all hot surfaces (Sun's surface temperature is around 6000K), in *all* wavelengths.
Most (percentage wise) is in visible spectrum but sun is quite bright in x-rays (or microwaves, infrared or even radio waves) too.
Image

(Since sun is quite big and close by - total energy even in x-ray wavelengths is quite large)

- Most of "brightness" is from reflected light (both in visible and also in x-rays) from sun by moon. (Some is coming from cosmic rays - or reflected cosmic rays from moon)

- Nothing like fission etc is going on surface of the moon. They are jus "bouncing off" from the moon. Of course, like all surfaces, there is some "fluorescence" ..depending on the surface there may be some frequency change and characteristics of the surface elements will be there in the reflected secondary x-rays. (This is of course, very similar to a red object reflecting more light in red region and how we see colors in the reflected/scattered light).

Yes, we are fortunate that most of the harmful radiation is absorbed by our atmosphere. Also due to earths magnetic field (earth's spin) other charged cosmic ray particles gets deflected.

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Re: Chandrayan-2 Mission

Postby ramana » 18 Oct 2019 04:10

Thanks for the detailed explanation!!!
Ok so its mostly reflected x-rays and some secondary x-ray emission.

I know the basic Roentgen theory of x-ray emission.

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Re: Chandrayan-2 Mission

Postby Amber G. » 18 Oct 2019 05:24

^^Thanks.
One important part as I posted before (for example here that apart from - High Resolution Camera (OHRC) other instruments on CY2 are top class and important and seem to be working fine. They released nice pictures from OHRC and we know TMC-2 is working fine. Similarly CLASS and XSM (x-rays).. and now IIRS (infrared). (That leaves only radio spectrum, hope we hear about that soon.)

IIRS was the first one, per ISRO, to "see" Vikram (thermal image) but ISRO has not given much details then.

Interesting part, as I noted before, other frequencies (X-rays and Infrared - CLASS/XSM/IIRS) help locate metal/chemical composition etc so it may help to locate Vikram too , as it will give more data in other spectrum.

***
Hope they publish data from DFSAR and tell us it is working nicely... Hope CY2 makes many important discoveries regarding water before NASA's VIPER - water sniffing rover at the South Pole (in 2022).

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Re: Chandrayan-2 Mission

Postby somdev » 18 Oct 2019 12:22

Thanks Amber G.

We need to send a bigger lander with more scientific payload to the moon's polar region

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Re: Chandrayan-2 Mission

Postby Amber G. » 18 Oct 2019 21:41

Also in the news: Japan's 1st Moon Rover to Touch Down in 2021
Link: https://www.space.com/japan-first-moon-rover-astrobotic-peregrine.html

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Re: Chandrayan-2 Mission

Postby somdev » 18 Oct 2019 22:39

Also, UK’s moon rover with spider legs

https://spacebit.com/mooncrawler

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Re: Chandrayan-2 Mission

Postby Amber G. » 21 Oct 2019 23:32

Down the memory lane -

11 years ago Chandrayaan-1 was launched! (Oct 22 - 2008). It found water on the moon!

The Moon Mineralogical Mapper (M3), an infrared spectrometer, detected not just water but it could also differentiate between ice, liquid water and water vapor based on how the surface absorbed infrared light. M3 confirmed that the Moon hosted water once and for all.

Distribution of water ice on the lunar poles mapped by Chandrayaan 1 instrument M3. ( Photo Source NASA)
Image

This image shows the distribution of surface ice at the moon’s south pole (left) and north pole (right), as detected by M3 on CY-1,. Blue represents ice locations, and the gray scale corresponds to surface temperature, with darker gray representing colder areas and lighter shades indicating warmer ones.(Image: © NASA)

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Re: Chandrayan-2 Mission

Postby Amber G. » 22 Oct 2019 21:02

Amber G. wrote:
One important part ... High Resolution Camera (OHRC) other instruments on CY2 are top class and important and seem to be working fine. They released nice pictures from OHRC and we know TMC-2 is working fine. Similarly CLASS and XSM (x-rays).. and now IIRS (infrared). (That leaves only radio spectrum, hope we hear about that soon.)
<snip>
Hope they publish data from DFSAR and tell us it is working nicely... Hope CY2 makes many important discoveries ....


Looks like they listened and Here it is! :) From DFSR.

Chandrayaan-2 Orbiter’s DF-SAR has been operated in full-polarimetry mode- a gold standard in SAR polarimetry, and is the first-ever by any planetary SAR instrument.

Initial imaging and observations by Chandrayaan-2 Dual-Frequency Synthetic Aperture Radar (DF-SAR)

Wow!

A L-band fully-polarimetric, 20m slant-range resolution image of Pitiscus-T crater. The image is a color composite of different transmit-receive polarization responses of the imaged region.

Image

And

Image

11 Years after CY-1.

Source: ISRO

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Re: Chandrayan-2 Mission

Postby Amber G. » 22 Oct 2019 21:15

^^^ (Some background and other information from ISRO about these photographs):

- Synthetic Aperture Radar (SAR) is a powerful remote sensing instrument for studying planetary surfaces and subsurface due to the ability of the radar signal to penetrate the surface. It is also sensitive to the roughness, structure and composition of the surface material and the buried terrain. And you don't need sunlight :).

Previous lunar-orbiting SAR systems such as the S-band hybrid-polarimetric SAR on ISRO’s Chandrayaan-1 and the S & X-band hybrid-polarimetric SAR on NASA’s LRO, provided valuable data on the scattering characterisation of ejecta materials of lunar impact craters. However, L & S band SAR on Chandraayan-2 is designed to produce greater details about the morphology and ejecta materials of impact craters due to its ability of imaging with higher resolution (2 - 75m slant range) and full-polarimetric modes in standalone as well as joint modes in S and L-band with wide range of incidence angle coverage (9.5° - 35°). In addition, the greater depth of penetration of L-band (3-5 meters) enables probing the buried terrain at greater depths. The L & S band SAR payload helps in unambiguously identifying and quantitatively estimating the lunar polar water-ice in permanently shadowed regions.
Image
Image

A convenient approach towards discerning the radar information is to prepare images using two derived parameters, ‘m’ the degree of polarization and ‘ä’ the relative phase between the transmit-receive polarized signals.

Figure 1 shows the m-ä decomposition images of the first datasets acquired over lunar south polar regions in L-band high-resolution (2m slant-range resolution) hybrid polarimetric mode. It produces colour composite images where ‘even-bounce’, ‘volume or diffused’ and ‘odd-bounce’ scatterings of a pixel are represented in red (R), green (G), and blue (B) image planes, respectively. It is important to note that the obtained resolution is one-order better than the earlier best by a lunar-radar.

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Re: Chandrayan-2 Mission

Postby Amber G. » 26 Oct 2019 05:58

Meanwhile, the LRO's last pass, I have not heard anything about locating Vikram. According to Noah Petro, NASA’s Lunar Reconnaissance Orbiter project scientist, “I suspect, based on what they’ve said, that it could be just that we’re not looking at the right place or we just can’t see it because of the illumination. Until we know more details about where it is, it’s going to be very hard for us to find it.”

Due to the fact it is near the south pole .. lighting, though better than last time, is never too good (max elevation about 20 degrees) and there are shadows.

(Some were sort of grumbling that India isn’t exactly forthcoming with location details - or ISRO itself doesn't know what happened in the last few moments. Anyway LRO makes a pass every month and LRO is going to look (that's it's job).. I think lighting is even better next month's flyby. .It makes a pass about every month)... Similarly CY-2 should be making a good flyby (again once every month or so) so it should be looking too)

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Re: Chandrayan-2 Mission

Postby somdev » 26 Oct 2019 12:41

Now that the elections are over and governments formed, ISRO might consider releasing its ‘national committee’ findings to the public

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Re: Chandrayan-2 Mission

Postby chetak » 26 Oct 2019 23:12

OT but couldn't find the thread to post this


twitter


Imagine how cool it would be if we could see in every wavelength! Here’s what the sun looks like in different wavelengths (NASA pic)


Image

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Re: Chandrayan-2 Mission

Postby Vayutuvan » 26 Oct 2019 23:26

physics thread?

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Re: Chandrayan-2 Mission

Postby sanjaykumar » 27 Oct 2019 01:08

Yeah, I've wanted a Hydrogen alpha filter for my scope. But if I see Savitra in all his glory, life may seem mundane thereafter.

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Re: Chandrayan-2 Mission

Postby UlanBatori » 28 Oct 2019 02:07

I thought sunlight spectrum peak is dominantly around green-yellow. All the others are low contributors.

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Re: Chandrayan-2 Mission

Postby ashbhee » 28 Oct 2019 08:00

I think this is what ISRO should do.
They should not wait for 3 or 4 years to launch Chandrayaan - 3.
Just launch lander only mission, Virkarm - 2. It should be a replica of Vikram - 1 plus any changes that needs to be done for the landing mechanism.
Since it is a repeat mission, it can be done quickly and cheaply. Since it is much lighter mission it can be launched using PSLV or even the new SSLV.

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Re: Chandrayan-2 Mission

Postby Varoon Shekhar » 28 Oct 2019 13:34

^
Absolutely! Chandrayaan-3 should be totally independent of the lander/rover issue( though it can have one too). ISRO should build another lander and rover as quickly as possible and launch it, perhaps even use the services of a non-Indian vehice if an Indian one is not available. They shouldn't think that they must have a sophisticated orbiter as part of the mission. Team Indus/Axiom Labs is also building a lander and rover, and are planning to launch it on board a US rocket next year. Would be amazing if they can do it!

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Re: Chandrayan-2 Mission

Postby arvin » 28 Oct 2019 17:45

ashbhee wrote:I think this is what ISRO should do.
They should not wait for 3 or 4 years to launch Chandrayaan - 3.
Just launch lander only mission, Virkarm - 2. It should be a replica of Vikram - 1 plus any changes that needs to be done for the landing mechanism.
Since it is a repeat mission, it can be done quickly and cheaply. Since it is much lighter mission it can be launched using PSLV or even the new SSLV.


PSLV fourth stage PS4 can only deliver till parking orbit. It is restartable, but wont have the feul for the 5 gravity assist maneovres to send the lander only config to moon capture orbit. Something like fregat would be required which we dont have.
Chandra yaan 2 was a closely coupled design in which lander piggy backed on the orbiter.
Lander only has feul to do the coarse and fine breaking after its drop from 100 km orbit.

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Re: Chandrayan-2 Mission

Postby YashG » 28 Oct 2019 18:00

UlanBatori wrote:NDTV will publish it, they always like to publish the most gory images after disasters and terror attacks with no consideration for victims' relatives. :)

That spot has to go to IndiaTV. Nobody can beat India TV on insensitive coverage!

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Re: Chandrayan-2 Mission

Postby Varoon Shekhar » 29 Oct 2019 10:22

arvin wrote:
Chandra yaan 2 was a closely coupled design in which lander piggy backed on the orbiter.
Lander only has feul to do the coarse and fine breaking after its drop from 100 km orbit.


Thanks for the info. A few of us are over-eager( with justification) to see another lander-rover combination go up as soon as possible. Without considering whether the lander in question could, sans orbiter, circle the earth multiple times, enter into lunar trajectory, undergo lunar capture, and then de-orbit, and all of this using the onboard fuel. However, couldn't a Vikram Lander go up sooner on a French, Russian or American vehicle? Would cost India a bit, of course.

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Re: Chandrayan-2 Mission

Postby arvin » 29 Oct 2019 12:38

Sure it would cost a bomb and north block will have a massive heart attack.
I think a standalone lander mission cant be done using a PSLV XL, since feul itself will take around 1500 kg. vikram had 700 kg feul only for landing purpose. orbiter had 1700 kg feul. Assuming half is for moon orbital insertion and half for station keeping, feul load itself comes to max lift capacity of the vehicle. Leaving little room for experiments or anything else.


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