Indian Space Program: News & Discussion - Sept 2016

The Military Issues & History Forum is a venue to discuss issues relating to the military aspects of the Indian Armed Forces, whether the past, present or future. We request members to kindly stay within the mandate of this forum and keep their exchanges of views, on a civilised level, however vehemently any disagreement may be felt. All feedback regarding forum usage may be sent to the moderators using the Feedback Form or by clicking the Report Post Icon in any objectionable post for proper action. Please note that the views expressed by the Members and Moderators on these discussion boards are that of the individuals only and do not reflect the official policy or view of the Bharat-Rakshak.com Website. Copyright Violation is strictly prohibited and may result in revocation of your posting rights - please read the FAQ for full details. Users must also abide by the Forum Guidelines at all times.
Vivek K
BRF Oldie
Posts: 2063
Joined: 15 Mar 2002 12:31

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Vivek K » 14 Jun 2019 07:48

A Nandy wrote:Live now: https://www.republicworld.com/livetv

https://twitter.com/republic/status/1138728440935268354

Launch on July 15, 2:51 AM
…….. For one full lunar day, the lander & rover will be functioning & carry out scientific experiments.

…..
Image


Is that a typo? One day only?

srin
BRFite
Posts: 1760
Joined: 11 Aug 2016 06:13

Re: Indian Space Program: News & Discussion - Sept 2016

Postby srin » 14 Jun 2019 08:12

Vivek K wrote:
Is that a typo? One day only?


One lunar day saar, equivalent to some 14 earth days. IIRC, it's because rover is solar powered and can't last the lunar night.

Najunamar
BRFite
Posts: 175
Joined: 28 Dec 2007 16:40
Location: USA

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Najunamar » 14 Jun 2019 08:12

No typo, 1 lunar day = 14 earth days.

Vivek K
BRF Oldie
Posts: 2063
Joined: 15 Mar 2002 12:31

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Vivek K » 14 Jun 2019 08:14

Najunamar wrote:No typo, 1 lunar day = 14 earth days.


Hmmm! Need to give out facts for dumb people like me.

Also does the rover wake up after the lunar night? Why would it die?

Najunamar
BRFite
Posts: 175
Joined: 28 Dec 2007 16:40
Location: USA

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Najunamar » 14 Jun 2019 08:16

Also, rover supposed to travel 1 cm/s and travel 500 m in 50000 s = 13.89 hours. I hope that 500 m distance is extent of max displacement rather than actual travel since there is plenty of time in 14 days to also account for the sampling at any given location.
Last edited by Najunamar on 14 Jun 2019 08:16, edited 1 time in total.

Najunamar
BRFite
Posts: 175
Joined: 28 Dec 2007 16:40
Location: USA

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Najunamar » 14 Jun 2019 08:16

Rover...and not river :rotfl:

Najunamar
BRFite
Posts: 175
Joined: 28 Dec 2007 16:40
Location: USA

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Najunamar » 14 Jun 2019 08:21

Perhaps since the temp can go to approx 100 K which could impair the operations of the rover equipment? Any details from Gurus?

Vips
BRFite
Posts: 1838
Joined: 14 Apr 2017 18:23

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Vips » 15 Jun 2019 02:59

Chandrayaan 2: Meet India’s ‘Rocket Women’ who are leading the country’s second moon mission.

India’s second quest to the Moon which is all set for official launch on July 15, is spearheaded by two women at the supreme helm of all things! India’s very own ‘Rocket Women’, as popularly titled for their superior scientific expertise are leading Chandrayaan 2, the Indian Space Research Organisation’s (ISRO) pivotal Lunar project. ISRO scientist Ritu Karidhal and electronics system engineer Muthayya Vanitha, both in their 40s, will be leading the Moon Mission’s main components- project oversight as well as crucial final phase of the landing. Ritu Karidhal, who was the deputy operations manager for the Mars Mission will now be the mission director for Chandrayaan 2. Karidhal holds a master’s degree in the field of Aerospace Engineering from the prestigious Indian Institute of Science (IISc). Muthayya Vanitha will be the project director for Chandrayaan 2 and is an electronics systems engineer. With scientific prowess and critical expertise for Space Engineering, these senior women space scientists have been associated with ISRO for close to two decades now and were a part of launches as well as sub-system development for satellites.

K Sivan, ISRO Chairman was quoted in a report by The Indian Express as saying that Chandrayaan-2 will mark a historic achievement as it is the first time for a planetary mission where women scientists are in charge. ISRO has previously had women project directors for the launch of communication and other satellites. According to K Radhakrishnan, former ISRO chairman, a project director is responsible for the project from the very beginning, which involves getting the entire system configured, reviewed, assembled and implemented, and also to become a single-point authority for the overall project.

He added that a mission director handles all the things which have to be done on the spacecraft from the time it is inserted into the orbit, from the initial operations, raising the orbit to taking all the contingency actions when required. Whereas the project director is to be a part of the task for years, while the mission director gets involved once the satellite is injected into orbit.

M Annadurai was quoted saying that from a project point of view, this will be the first time that Vanitha is in charge and it is a big turning point for her. However, she was in charge of another domain of making data handling systems for all their remote-sensing satellites. M Annadurai added that this is not something new for ISRO, to have women in charge of core projects. M Annadurai was the project director for Chandrayaan 1 as well as Chandrayaan 2, but later quit the project.

Quick Facts: Know Muthayya Vanitha, Project Director, Chandrayaan 2

She was the winner of the best woman scientist award of the Astronautical Society of India in the year 2006, and has been the deputy project director for data systems for the remote sensing satellites Cartosat-1, Oceansat-2 and Megha-Tropiques.
She also headed the telemetry as well as the telecommand divisions at the digital systems group at the satellite centre, which is now the UR Rao Space Centre.
She was a key scientist involved in ensuring that the Mangalyaan satellite which was launched on November 5, 2013
Quick Facts: Know Ritu Karidhal, Mission Director, Chandrayaan 2
A simple girl from the city of Lucknow, she got a chance to be associated with the Mars Mission with her never ending inquisitive spirit to know more about outer space.
For the Mars Mission, she was one of the persons who was identified to carry out the operations of the satellite. The automation on board was done for the first time in the Mars mission and Karidhal assisted in all of these operations. This is regarded as the turning point of her scientific career.

krishGo
BRFite -Trainee
Posts: 76
Joined: 03 Feb 2017 04:24

Re: Indian Space Program: News & Discussion - Sept 2016

Postby krishGo » 18 Jun 2019 03:59

Najunamar wrote:Perhaps since the temp can go to approx 100 K which could impair the operations of the rover equipment? Any details from Gurus?


IMO Temperature gradient is the bigger problem than power generation. There was some talk of ISRO using Russian RHU / RTG, which would keep the critical components warm and generate electricity if they wanted limited operation during the lunar night. I beleieve they did not go through with this.

Temperatures on the moon can get much more severe than places like Mars due to variety of different factors. The lunar night, is 14 earth days long and there is almost no atmosphere to retain any heat.

The Chinese Yutu rover was equipped with an RTG and even then could only survive a single lunar night. This illustrates the problems of having long term robotic missions.

I believe ISRO even had a proposal where the rover would go back into the lander during the lunar night to decrease exposure to the low temperatures. But they do not seem to have gone forward with it.

The approach now is quite reasonable for our first rover. We should also parallely develop the expertise inhouse to develop RTGs for future missions. (which I beleive BARC is working on)
Last edited by krishGo on 18 Jun 2019 04:25, edited 1 time in total.

krishGo
BRFite -Trainee
Posts: 76
Joined: 03 Feb 2017 04:24

Re: Indian Space Program: News & Discussion - Sept 2016

Postby krishGo » 18 Jun 2019 04:22

sanjaykumar wrote:Docking technology should be developed prior to human space flight lest the astronauts be marooned.

Is there a common standard for docking mechanisms and interlocks? Note this is not essential for rescue but would make things easier.


Well, usually docking isn't seen as an critical technology for human spaceflight itself. The general order of building a HSF program has been
1) Develop Critical Technologies (Life Support / Reentry / Crew Escape / Human rated launcher etc)
2) Develop technology for EVA (space walk) (EVA Suit / Life Support etc)
3) Scaling up (Docking, Space labs, space station)


ISRO should in general follow this template that has been followed by all HSF capable programs (Russia, USA, China). But we are already seeing ISRO not adhering to it strictly. Examples are them not planning to do an unmanned orbital test flight before the actual manned flight or planning to have 3 vymonauts on the first manned launch (all other countries have had only 1 astronaut on their first launches)

To answer your second question, yes, there is an international standard for docking.

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

SSridhar
Forum Moderator
Posts: 23639
Joined: 05 May 2001 11:31
Location: Chennai

Re: Indian Space Program: News & Discussion - Sept 2016

Postby SSridhar » 18 Jun 2019 06:45

For the uninitiated like me,

RHU - Radioisotope heater unit
RTG - Radioisotope Thermoelectric Generator

rajsunder
BRFite
Posts: 587
Joined: 01 Jul 2006 02:38
Location: MASA Land

Re: Indian Space Program: News & Discussion - Sept 2016

Postby rajsunder » 18 Jun 2019 08:21

Najunamar wrote:Also, rover supposed to travel 1 cm/s and travel 500 m in 50000 s = 13.89 hours. I hope that 500 m distance is extent of max displacement rather than actual travel since there is plenty of time in 14 days to also account for the sampling at any given location.

The moon rovers designed by Russia in 1970's have survived on moon for 322 days and 120 days.

During its 322 Earth days of operations, Lunokhod 1 travelled 10.5 km (6.5 miles) and returned more than 20,000 television images and 206 high-resolution panoramas.[16] In addition, it performed twenty-five soil analyses with its RIFMA x-ray fluorescence spectrometer and used its penetrometer at 500 different locations.

Lunokhod 2 operated for about four months, covered 42 km (26 miles) of terrain,[17] including driving into hilly upland areas and rilles. Lunokhod 2 held the record for the longest distance of surface travel of any extraterrestrial vehicle until 2014.[9] It sent back 86 panoramic images and over 80,000 television pictures. Many mechanical tests of the moon's surface, laser ranging measurements, and other experiments were completed during this time.

If Soviets could do such a long lasting rovers, why can't we do it in 2019?

mridulmm
BRFite -Trainee
Posts: 32
Joined: 27 Feb 2017 03:13

Re: Indian Space Program: News & Discussion - Sept 2016

Postby mridulmm » 18 Jun 2019 08:56

rajsunder wrote:If Soviets could do such a long lasting rovers, why can't we do it in 2019?


Launch capacity. Compare the launch mass of Lunokhod 1 with Chandrayan 2

https://en.wikipedia.org/wiki/Lunokhod_1 [5600 KG]
https://en.wikipedia.org/wiki/Chandrayaan-2 [3800 KG]

dinesha
BRFite
Posts: 1087
Joined: 01 Aug 2004 11:42
Location: Delhi

Re: Indian Space Program: News & Discussion - Sept 2016

Postby dinesha » 18 Jun 2019 15:47

Orbiter reached the launch port, SDSC SHAR Sriharikota on 15th June.
Image

Singha
BRF Oldie
Posts: 66591
Joined: 13 Aug 2004 19:42
Location: the grasshopper lies heavy

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Singha » 18 Jun 2019 16:25

Lunokhod for its day was claimed to have astonished murican designers with its longevity and capability.
some old school minds cooked up that rover for sure.

prasannasimha
Forum Moderator
Posts: 1125
Joined: 15 Aug 2016 00:22

Re: Indian Space Program: News & Discussion - Sept 2016

Postby prasannasimha » 18 Jun 2019 18:19

The rover is solar powered. Reactivation after 14 days of lunar night may not be possible though an attempt to revive it will be attmpted.

Katare
BRF Oldie
Posts: 2505
Joined: 02 Mar 2002 12:31

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Katare » 18 Jun 2019 19:04

What really low temperature does? All frozen liquids should liquify, everything warmed up and ready to go when day comes back. What specifically is the technical holdup? Does electronics/semiconductors change irreversibly? Mechanically temperature delta shouldn't be an issue?
Any informed moulana please issue a fatwah

Katare
BRF Oldie
Posts: 2505
Joined: 02 Mar 2002 12:31

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Katare » 18 Jun 2019 19:05

May be the battries?

Katare
BRF Oldie
Posts: 2505
Joined: 02 Mar 2002 12:31

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Katare » 18 Jun 2019 19:07

I had my car battery frozen into a bulging hulk when temperatures hit -30F last winter. But a fully charged battery should be able to keep itself warm for 14 days

Varoon Shekhar
BRFite
Posts: 1816
Joined: 03 Jan 2010 23:26

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Varoon Shekhar » 18 Jun 2019 19:52

"Examples are them not planning to do an unmanned orbital test flight before the actual manned flight..."

There are two or three unmanned flights of the space capsule before the manned one.

From WIKI: Following two uncrewed flight demonstrations of the spacecraft, a crewed Gaganyaan is slated to be launched on the GSLV Mk III launcher in late 2021.

A Nandy
BR Mainsite Crew
Posts: 342
Joined: 06 Sep 2009 23:39

Re: Indian Space Program: News & Discussion - Sept 2016

Postby A Nandy » 18 Jun 2019 21:48

Yeah direct to space not a good idea :D

disha
BR Mainsite Crew
Posts: 7115
Joined: 03 Dec 2006 04:17
Location: gaganaviharin

Re: Indian Space Program: News & Discussion - Sept 2016

Postby disha » 18 Jun 2019 23:08

rajsunder wrote:The moon rovers designed by Russia in 1970's have survived on moon for 322 days and 120 days.


Did you check out the heating source of Lunakhod?

rajsunder wrote:If Soviets could do such a long lasting rovers, why can't we do it in 2019?


Just a request to not inflict yourself with self-lacerating statements like above. Also request not to build a false straw man and proceed to compare against that false straw man and indulging in rona-dhona.

Have you thought through before you compared "days of operation":

1. What was the original mission parameters of Lunakhod-1? What are the current mission parameters of Chandrayan-2

2. What was achieved and what is achievable?

3. To achieve what Chandrayan-2's mission parameters - does it require more than the requisite mission days?

Why the focus on number of days? You remind me of my school buddies. I used to finish my exams in half the time and then there will be always somebody who will tell me that the other person was sitting till the very end and scare me to death on how well I would have done. Till the results come.

Above statement of yours is like that: Lunakhod-1 spent 300+ earth days, why cannot Chandrayan spend as much if not more? Not sure what adult complex you are planning to get scratched!

Vivek K
BRF Oldie
Posts: 2063
Joined: 15 Mar 2002 12:31

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Vivek K » 18 Jun 2019 23:19

No need to react so defensively. We have all seen the longevity of the Mars Rovers too. So the question is innocent and perhaps natural for the layman to ask - it is therefore an attempt to learn what one doesn't know. The posters (including yourself) have clearly provided a wealth of information to understand.

And this type of information should be provided by ISRO to ensure that the message is driven home - that they have accomplished what others could not.

disha
BR Mainsite Crew
Posts: 7115
Joined: 03 Dec 2006 04:17
Location: gaganaviharin

Re: Indian Space Program: News & Discussion - Sept 2016

Postby disha » 18 Jun 2019 23:33

Katare wrote:I had my car battery frozen into a bulging hulk when temperatures hit -30F last winter. But a fully charged battery should be able to keep itself warm for 14 days


Katare'ji, catch-22 here. After day, there is long night and then there is day. To have the mission operate for say 'two lunar days', the system has to be designed to be effective at a minimum across 2 'day' and 1 'night' lunar time.

A fully charged battery has to spend energy inefficiently to convert it back to heat and keep the battery warm. Till the next charging cycle. At that point, the charging cycle should be long enough to recharge the entire battery pile. While due to temperature extremes the half life of the battery drops down precipitously. Put it this way, lander/rover has to survive 14 nights keeping itself warm, then has to recharge fully to perform its duties and again prepare to survive for 14 nights, but now the battery capacity has depleted. In nutshell, every cycle the number of effective days of work reduces.

Here is the rover details:

The rover, Pragyan (also Pragyaan), is a 6-wheeled vehicle with a mass of 27 kg that runs on 50 W of solar power and can travel up to 500 m at a speed of 1 cm per second. The rover communicates directly with the lander. the rover will hold cameras, alpha-proton X-ray spectrometer, and a laser-induced ablation spectroscopy experiment.


And I am sure that the boffins at ISRO would have thought through the above and come up with an optimal battery size/weight/volume that can be launched and serve the mission objectives. Once the primary mission objectives are met, secondary mission objectives can be taken up. Or the mission extended. Nobody is arguing against that.

For example, the primary mission objective of MOM was - "just reach there successfully" !!!

For Chandrayaan-2, mission can be divided into three phases - Orbiter/Lander/Rover. Orbiter mission life is 1 year while the Lander is 14 earth days and rover is designed for 500 mtrs.

This is a very well designed science mission.

If one has to compare, then the question one must ask is what will the rover achieve in 1 km of travel distance (remember that means it has to go for 3 lunar days or 42 earth days) that it cannot achieve in 500 m of travel distance (that means mission life is 1 lunar day or 14 earth days). If the answers are not specific or not contributing much to new knowledge, then why even bother?

Hence why complicate the mission for diminishing returns?
Last edited by disha on 18 Jun 2019 23:48, edited 1 time in total.

disha
BR Mainsite Crew
Posts: 7115
Joined: 03 Dec 2006 04:17
Location: gaganaviharin

Re: Indian Space Program: News & Discussion - Sept 2016

Postby disha » 18 Jun 2019 23:46

Vivek K wrote:No need to react so defensively. We have all seen the longevity of the Mars Rovers too. So the question is innocent and perhaps natural for the layman to ask - it is therefore an attempt to learn what one doesn't know. The posters (including yourself) have clearly provided a wealth of information to understand.

And this type of information should be provided by ISRO to ensure that the message is driven home - that they have accomplished what others could not.


1. ISRO cannot provide any information for any out-of-field comparisons borne out of ignorance.

2. A genuine query will be a simple query - "Why is the mission life of rover set at 14 earth days?". However the poster in question brought up the query as follows:

The moon rovers designed by Russia in 1970's have survived on moon for 322 days and 120 days. If Soviets could do such a long lasting rovers, why can't we do it in 2019?


It is a simple straightforward comparison. If 'A' could do it 40 years back, why is 'B' not able to do it now?

3. In your own comparison, you are conflating Mars with Moon. Of course one must not confuse between two planetary bodies. Also, a rover designed by Nasa for Mars cannot be conflated with a rover designed for Moon by ISRO.

Coming to Mars rover (since you brought it up)., the Sojourner rover was

Designed for a mission lasting 7 sols, with possible extension to 30 sols,[2] it was in fact active for 83 sols.


My urge will be, after going there - what does ISRO plan to do? In short, what is the mission?

Vivek K
BRF Oldie
Posts: 2063
Joined: 15 Mar 2002 12:31

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Vivek K » 19 Jun 2019 23:19

Thanks. for the information. It is because of posters like you that layman like us come to BRF. I can appreciate the passion.

krishGo
BRFite -Trainee
Posts: 76
Joined: 03 Feb 2017 04:24

Re: Indian Space Program: News & Discussion - Sept 2016

Postby krishGo » 20 Jun 2019 02:05

Varoon Shekhar wrote:"Examples are them not planning to do an unmanned orbital test flight before the actual manned flight..."

There are two or three unmanned flights of the space capsule before the manned one.

From WIKI: Following two uncrewed flight demonstrations of the spacecraft, a crewed Gaganyaan is slated to be launched on the GSLV Mk III launcher in late 2021.


Yes! My bad! I mixed up the plan for unmanned launch with live abort test (which I believe is not happening but my knowledge on the plan is dated).


Katare wrote:What really low temperature does? All frozen liquids should liquify, everything warmed up and ready to go when day comes back. What specifically is the technical holdup? Does electronics/semiconductors change irreversibly? Mechanically temperature delta shouldn't be an issue?
Any informed moulana please issue a fatwah


That is very generic question and here is an interesting thread about it on Stack exchange:

https://electronics.stackexchange.com/questions/143921/why-do-electronics-have-a-low-temperature-limit

Well, we need to remember that the rover will operate independently to a large extent. If the battery is out there is no one that can go and replace it. The onboard computer is a critical component. For example, in the Mars Exploration Rovers, if the power availability was too low, the onboard computer would switch off all components and just have an onboard clock running. The clock would wake up the rover after certain intervals to check the battery status and then if the power was still not sufficient, it would put the rover back to sleep. One of the MERs (Spirit?), after not being blocked from sunlight due to a major duststorm, could not wake up from this state. This, even when MER were equipped with RHU units to keep the core of the rover warm-enough!

ldev
BRFite
Posts: 1627
Joined: 06 Nov 2002 12:31

Re: Indian Space Program: News & Discussion - Sept 2016

Postby ldev » 20 Jun 2019 06:36

Can some expert opine on what would be the mass that GSLV Mk 3 (which I believe is being used for the Chandraayan mission) will be capable of injecting into Lunar orbit if the Hohmann transfer orbit is not used. The Chandraayan 2 mission orbiter and lander is about 3800 kg? I presume that ISRO is using the Hohmann transfer to ensure the maximum possible payload is inserted into lunar orbit and hence the roughly 6-8 weeks from the launch date to the landing date. China also appears to be using the Hohmann transfer as it's last mission moon lander took about 4 weeks from launch to landing.

In contrast the Apollo missions reached lunar orbit about 3 days after launch and most landed on the surface a few hours after inserting into lunar orbit. The Apollo 11 lander was about 4900 kg vs the Chandraayan 2 lander at about 1470 kg.

ldev
BRFite
Posts: 1627
Joined: 06 Nov 2002 12:31

Re: Indian Space Program: News & Discussion - Sept 2016

Postby ldev » 20 Jun 2019 19:11

Found a JPL document which defines acceleration required for various lunar transfers i.e. defined by them as low energy vs high energy direct transfers. Will take some time to go through it and understand it and then translate energy requirements into corresponding payload/mass for a given booster such as GSLV Mk 3.

https://descanso.jpl.nasa.gov/monograph ... Orbits.pdf

krishGo
BRFite -Trainee
Posts: 76
Joined: 03 Feb 2017 04:24

Re: Indian Space Program: News & Discussion - Sept 2016

Postby krishGo » 20 Jun 2019 23:56

Not at all an expert.

The Mk3 should theoretically be able to put around 2 tons on a direct transfer (2 burn Hohmann orbit) to moon. I am not entirely sure if it can actually do that. This transfer requires the rocket to make a long upper stage burn at apogee to be the most efficient. This requires a restartable upper stage. Currently, the C25 doesn't have this ability.

To get to the moon, the 3 most used ways are:

1) 2 Burn Hohmann - The fastest, most efficient way to get to the moon in terms of delta-V required. Launch into a low earth parking orbit, one more burn at apogee by the upper stage to send the target in the direction of the moon, and then one burn by the target to decelerate itself and get captured by the moon's gravity. I believe PSLV with the restartable PS4 upper stage is the only Indian rocket the can do this and even then for a very small payload. Used by Apollo, MRO etc.

Image


2) Multi Burn Hohmann - The lesser efficient way to get to moon in terms of delta V. The probe is launched into a highly elliptical orbit around the earth and then continuously enlarges its orbits on its own power. Advantage is that you can use a less powerful launcher and there is more freedom for adjusting to problems due to the multiple burns. Disadvantage is the time taken and the fuel needed to be carried by the probe for the enlargement burns. Used by Change (Chinese mission), Chandrayaan-1 and the recent Israeli Beresheet mission among many others. This is what we will be using for Chandrayaan-2

Image

3) Ballistic Trajectory - The approach that uses the least energy and takes the most time. You basically launch the probe into a ballistic trajectory with its apogee much further than the distance of the moon. On the way back, the probe gets captured by the moon's gravity. I think Japans Hiten probe first demonstrated the use of this trajectory.

Image

Indranil
Forum Moderator
Posts: 7462
Joined: 02 Apr 2010 01:21

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Indranil » 21 Jun 2019 01:49

One correction: CE20 is restartable 25 times. Demonstration to be carried out in future.

VenkataS
BRFite
Posts: 246
Joined: 02 Apr 2010 03:38

Re: Indian Space Program: News & Discussion - Sept 2016

Postby VenkataS » 21 Jun 2019 02:27

HOW DOES ISRO’S GSLV MK-III FARE AGAINST SOME OF THE WORLD'S MOST POWERFUL ROCKETS?
https://www.firstpost.com/tech/science/ ... 41311.html

ArjunPandit
BRF Oldie
Posts: 2639
Joined: 29 Mar 2017 06:37

Re: Indian Space Program: News & Discussion - Sept 2016

Postby ArjunPandit » 21 Jun 2019 14:43

What articles like above miss is that we've fulfilled the needs of of a growing nation when the affluence levels were low... We have our specific needs which have been catered by them.. Yes things could have been better.. Bit that's always the case

Ashokk
BRFite
Posts: 460
Joined: 11 Aug 2016 06:14

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Ashokk » 21 Jun 2019 15:45

Landing On Lunar Surface: How Chandrayaan-2 Will Travel From Earth To Moon

While orbiting the Earth in an elliptical orbit, the module will be at its highest speed when it passes through the point in that orbit closest to the planet. This point is called the perigee. Exactly opposite to this point in the orbit is the apogee, where the module will be the furthest from the Earth and at its slowest speed. The speed varies across different points in the orbit due to the variation in the Earth’s gravitational pull.

The closer the module is to the Earth, the more the gravitational pull, and the greater the speed. Every time the module reaches the perigee, or the point of highest speed, the onboard engine fires, increasing its speed even more, pushing it into a higher, more elongated orbit as a result. With every burn of the onboard propulsion system, the module will keep spiralling outwards in increasingly elongated ellipses.

Image

Eventually, the module’s speed will reach escape velocity, required to escape Earth’s gravity, and its orbit elongated enough for it to set a course for moon. Some accounts say that after six burns of the engine, the module will be in a highly elliptical orbit which will pass close to the moon’s orbit around the Earth. To push the much smaller Chandrayaan-1 into such an orbit, called the Lunar Transfer Trajectory (LTT), ISRO had to fire its engine five times.

The Chandrayaan-2 module’s entry into the LTT will be timed in a way that it reaches close to the moon’s orbit when the moon is there itself. At this point, the module will get captured into the moon orbit through a precise manoeuvre by the onboard propulsion system. This manoeuvre, also called lunar orbit insertion, will reduce the module’s velocity significantly, enabling the moon’s gravitational field to pull it into a lunar orbit. Nearly one-and-a-half months after it set out for the moon, Chandrayaan-2 will be orbiting it.

This is largely how ISRO’s Mangalyaan, or the Mars Orbiter Mission, and Israel-based SpaceIL’s Beresheet lander, travelled from their orbits to the Mars and the moon, respectively. But NASA’s Apollo-11, a manned mission launched in 1969, was guided to the Lunar Transfer Trajectory by a single six-minute-long burn of the Saturn rocket’s third stage, like a sling shot. The spacecraft took just over three days to land on the lunar surface. How it did so is a story for another day.

Back to Chandrayaan-2.

So, the module has escaped Earth’s gravity and entered the lunar orbit.

Now, the orbiter and lander module will start revolving around the moon in an elliptical orbit. A series of manoeuvres will be used to progressively lower the altitude of the module and place it in a 100 km circular orbit around the moon. Visually, these manoeuvres will be the opposite of those performed around the Earth.

Image

Now comes the trickiest part of the mission. After the module arrives in the 100 km orbit, the lander will separate from the orbiter, which will continue to revolve around the moon. A separate entity now, the lander will de-boost with the firing of its four breaking engines. This manoeuvre will bring it to a periapsis of around 18 kilometres. When the lander reaches this point, that is at the height of 18 km, the onboard position detection camera and hazard avoidance sensor study the landing site for accuracy. Using the data obtained, the lander will autonomously determine the trajectory it will have to take to get to its pre-determined landing site, and steer itself to a location 100 metres above the site.

Here, the lander will hover and allow the hazard avoidance sensor to determine the safest landing point. Then, it will be guided to this point and at the height of 2 metres above this location, the thrust will be cut off and the lander will go into a free fall to the impact point with the landing legs attached to it absorbing the impact shock.

Image

Once on the ground, the lander will deploy the six-wheel rover to the lunar surface using a ramp. The rover will operate for 14-15 earth days, or one lunar day, on the surface of the moon in a semi-autonomous manner with ISRO exercising partial control from Earth.

Like NASA’s Mars rovers Spirit and Opportunity, the Pragyan (which translates to 'wisdom' in Sanskrit) rover sports six independently motorised wheels, but unlike the former two, its corner wheels do not steer. The orbiter, meanwhile, will continue to revolve around the moon and do so for a year.

Indranil
Forum Moderator
Posts: 7462
Joined: 02 Apr 2010 01:21

Re: Indian Space Program: News & Discussion - Sept 2016

Postby Indranil » 22 Jun 2019 00:29

Nice article. But some of the physics is wrong. Also the lander has five engines (instead of the initially planned 4 engines) which will be used in various combinations during the descent phase. In the Rough braking phase all 5 will be used. In the precision braking phase the four outer motors and the central motor will be used based on flight computer instructions.

A Nandy
BR Mainsite Crew
Posts: 342
Joined: 06 Sep 2009 23:39

Re: Indian Space Program: News & Discussion - Sept 2016

Postby A Nandy » 22 Jun 2019 20:11

https://www.moneycontrol.com/news/india ... 23831.html

European Space Agency (ESA) astronauts are already training in China in anticipation of the Chinese space station Tiangong becoming operational in 2022. Pakistan, too, :lol: has announced that its first human in space will be sent to the Tiangong. Russia plans to build a successor to the Mir (which was decommissioned in 1998 after many highly productive years in orbit) even as it partners with the Americans on the Deep Space Gateway: a space station which will be a staging post for manned missions to the Moon that NASA plans to begin in 2024.

Besides national efforts of wannabe space-farers such as Nigeria, South Korea and the United Arab Emirates, the global umbrella now expanding quickly over space research and exploration will have half a dozen private space stations in orbit by 2030.

While developing international partnerships is certainly the best way forward in space exploration, it would be foolish for any country to discount the importance of having its own space station. For no matter how well a country develops its technological capabilities, it would still be hamstrung if it cannot gather in-orbit data on its own — something the big players in space have long understood. As a scientist in Bangalore told this author, “So much of data has been collected over so many years of research aboard space stations. For example, it’s very important to determine the effects of space travel on the human body as long-time survivability is a must for any interplanetary mission. Nobody will give you this data as it is vital information for long term missions in space.”

gaurav.p
BRFite
Posts: 227
Joined: 04 May 2018 23:02

Re: Indian Space Program: News & Discussion - Sept 2016

Postby gaurav.p » 23 Jun 2019 21:59

found this while lurking around twitter.
Credits: https://mobile.twitter.com/hvtiaf/statu ... 7753959424
If Doc is out with the scalpel, it has truly started..
Literally out of the world
Mighty #gaganyaan
Image

prasannasimha
Forum Moderator
Posts: 1125
Joined: 15 Aug 2016 00:22

Re: Indian Space Program: News & Discussion - Sept 2016

Postby prasannasimha » 24 Jun 2019 07:33

Just as a correction the orientation 9f tge capture of the orbiter is wrong in the diagram

krishGo
BRFite -Trainee
Posts: 76
Joined: 03 Feb 2017 04:24

Re: Indian Space Program: News & Discussion - Sept 2016

Postby krishGo » 25 Jun 2019 01:09

gaurav.p wrote:found this while lurking around twitter.


Cool! I believe this was issued to the IAM personnel who will be involved in selecting the vyomonaut candidates from the IAF.

jaysimha
BRFite
Posts: 1001
Joined: 20 Dec 2017 14:30

Re: Indian Space Program: News & Discussion - Sept 2016

Postby jaysimha » 25 Jun 2019 15:10

https://www.business-standard.com/artic ... 780_1.html

Isro's new commercial arm NewSpace India officially inaugurated
NSIL was incorporated on March 6 2019, for commercially utilising research and development activities carried out by ISRO in the area of space
Image
NSIL was inaugurated by Isro's honorary adviser, Dr K Kasturirangan in the presence of chairman Dr K Sivan.


Return to “Military Issues & History Forum”

Who is online

Users browsing this forum: anishns, Bart S, EswarPrakash, Indrajit, JayS, Manish_Sharma, SSSalvi, Thakur_B, Vips and 67 guests