Author Topic: ISRO Mars Orbiter Mission - Nov 2013 launch to September 2014 arrival - UPDATES  (Read 453111 times)

Offline hop

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Do the planned mid-course corrections impart additional velocity to the spacecraft?
Mid course corrections will only make tiny changes in velocity, a few meters per second most likely. They are only to fine tune the trajectory.
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Or is there some figure or math that I got wrong here?
It's safe to assume numbers got garbled somewhere in the reporting, and there is probably little to be gained figuring out exactly where. It's possible the speaker was referring to different things, perhaps the distance traveled and the distance to Mars.

Offline plutogno

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Assuming that the current escape velocity of the spacecraft as around 11 km/s, I do get the math of covering 1 million km a day. But with that speed, wouldn't we be covering only around 300+ million km in 300 days? How would we cover 680 million km within the same timeframe (unless the spacecraft receives an acceleration to attain nearly double the escape velocity, that is..). Do the planned mid-course corrections impart additional velocity to the spacecraft?  Or is there some figure or math that I got wrong here?

11 km/s is the speed of the probe relative to Earth. that translates into more than 40 km/s relative to the Sun. then you have to consider that this speed is not constant at all along the elliptical orbit. it's not simple math anyway

Offline vineethgk

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Assuming that the current escape velocity of the spacecraft as around 11 km/s, I do get the math of covering 1 million km a day. But with that speed, wouldn't we be covering only around 300+ million km in 300 days? How would we cover 680 million km within the same timeframe (unless the spacecraft receives an acceleration to attain nearly double the escape velocity, that is..). Do the planned mid-course corrections impart additional velocity to the spacecraft?  Or is there some figure or math that I got wrong here?

11 km/s is the speed of the probe relative to Earth. that translates into more than 40 km/s relative to the Sun. then you have to consider that this speed is not constant at all along the elliptical orbit. it's not simple math anyway

Okay.. I get the general idea. There is a different frame of reference to consider while considering the distance and velocity, and I forgot that the orbital velocity would vary at different points of the orbit.

Thanks plutogno!

Offline vyoma

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Update from ISRO MOM mission page:
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Spacecraft has travelled a distance of 536,000 km by 17:00 hrs (IST) of Dec 2, 2013. It has crossed the distance to Moon's orbit around Earth (mean distance 385,000 km) this morning.

edit: modified to "westernize" the distances in km
« Last Edit: 12/03/2013 01:20 PM by input~2 »

Offline vyoma

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From http://www.isro.org/mars/updates.aspx:
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Spacecraft has traversed beyond the Sphere of Influence (SOI) of Earth extending about 925,000 km at around 1:14 hrs (IST) on Dec 4, 2013.

Online Galactic Penguin SST

In other news, how many MOM missions can you operate with the price of one Gareth Bale? The answer is 2.  ;)
Chinese spaceflight is a cosmic riddle wrapped in a galactic mystery inside an orbital enigma... - (not) Winston Churchill

Offline vyoma

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An overview of Trajectory Correction Maneuvers (TCM) planned by ISRO for MOM. First one's on 11th Dec 2013.

Source: ISRO MOM Facebook page.
« Last Edit: 12/04/2013 02:56 PM by vyoma »

Offline akula2

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It's interesting that the Indian language has short, simple words for such large numbers ("one hundred thousand" and "ten million" in English).
100,000 is 1,00,000 (lakh or some use lac)
1,000,000 (million) is 10,00,000 (just 10 lakh)
10,000,000 (10 million) is 1,00,00,000 (1 crore)
1,000,000,000 (billion) is 100,00,00,000 (100 crore) (highest unit in Hindi called: "Ek Arab")

Those are indeed wild ideas. Wild to the point of silly. The solar system is an enormous structure. Spacecraft are built for specific purposes. Flitting about is pointless and impractical, most likely impossible. Plus there were already discussions of slightly less-than-impossible ideas like aero-braking for extended missions.

As it stands our Indian colleagues are doing remarkable things incredibly fast on extremely lean budgets. These are stellar and thoroughly admirable accomplisments.
Many here aware how large Solar system is. There's nothing like wild ideas when it comes to few disciplines like Space or Engineering; Pioneer missions set themselves as 'living' examples. Or see the beauty of 'wildness' in RBSP with twin-spacecrafts. The same wildness was rewarded with a Nobel for chasing after God particle  :)

I'm sure (by experience) it's a matter of doing more missions with loads of dedicated funds, so MOM is rightly billed as a technology demonstrator  8)

So true, quite lean indeed. Many foreign employees shot questions on how India managed it etc.  Anyway, to the Prez Pranab, such budgets must be 'peanuts'  ;D (rejected aid, so British axed it. Thank god!). ISRO needs at least $3 billion allocation each year for 3-4 years to get that 'wild' drive on many levels. NASA allocated over $17 billion for this 2013, so they get to do many missions on various scales. ISRO's $850 million budget is severely constrained yet they're doing a good job. Very nice.

"We have not yet started any twitter feed. Please note that,
facebook.com/isromom is the only social media entity officially hosted by
ISRO."
That was expected - old habits die hard! I wrote to them 4 times with many inputs. ISRO should overhaul and use its website as the primary source (national brand) with loads of info/graphics/updates; FB/Twitter etc complementary or support tools. Example:

http://www.nasa.gov/mission_pages/rbsp/main/  (ongoing mission). 

Forgot to add, loved this FB photo:

« Last Edit: 12/07/2013 10:19 AM by akula2 »

Offline chota

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^
"Ensure zero after filling"!!!

Offline akula2

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Well, I take my words back regarding twitter stream!  :-X

Mars Orbiter Mission @Mangalyaan1  #Mangalyaan

India Space @India_inSpace

If anyone interested like me: MAVEN Mission @MAVEN2Mars
 




Offline jcm

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Well, I take my words back regarding twitter stream!  :-X

Mars Orbiter Mission @Mangalyaan1  #Mangalyaan

India Space @India_inSpace

If anyone interested like me: MAVEN Mission @MAVEN2Mars
 





Yes, but @Mangalyaan1 is not an ISRO account as far as I can tell. Don't know about India in Space.
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Offline vyoma

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I read in one of the comments by ISRO MOM Facebook page admin that MOM is approximately at a distance of 2,400,000 km from Earth and there's a 16 seconds delay in two-way communication.

And, here are few updates on TCM #1 that's tentatively scheduled at 6:30 AM IST Dec 11th 2013:
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Controllers of its various systems met at tracking centre ISTRAC in the evening to take stock of its situation and plan the operation, called trajectory correction manoeuvre (TCM). Team ISRO calls it fine-tuning of its course.

This TCM is needed as the spacecraft slightly overachieved its parameter, which can happen during operations such as the crucial December 1 manoeuvre, said M. Annadurai, Programme Director of the Mars Orbiter Mission.

Monday’s meeting was to take stock, finalise the duration of firing the smaller thrusters — tentatively for about 40 seconds at 6.30 a.m. [IST] on December 11 — and the rest of the TCM-1 strategy.

This time, all eight small 22-Newton thrusters on the spacecraft would be used to minutely slow it down.

http://www.thehindu.com/sci-tech/science/mars-craft-to-get-first-course-correction-tomorrow/article5441150.ece

Edit:
Here comes the official update from ISRO MOM Facebook page; refer attached image :)



« Last Edit: 12/10/2013 02:33 PM by vyoma »

Offline vyoma

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From ISRO MOM Facebook page:
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ISRO's Mars Orbiter Mission spacecraft started the 44 seconds long firing of its 22N thrusters, for the First Trajectory Correction Manoeuver.

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First Trajectory Correction Manoeuver completed successfully.

And, from mission page http://www.isro.org/mars/updates.aspx:
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The first Trajectory Correction Manoeuvre (TCM) of Spacecraft was carried out successfully at 06:30 hrs (IST) by firing the 22 Newton Thrusters for a duration of 40.5 seconds. The spacecraft is travelling at a distance of about 29 lakh (2.9 million) km away from Earth.

Offline AJA

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From the configuration of the RCS depicted in these pictures, and the fact that ALL 8 22N jets were fired for 40.5 seconds to give a translational delta-V correction...

https://www.facebook.com/photo.php?fbid=1405843782986895&set=a.1384034005167873.1073741827.1384015488503058&type=1&permPage=1


https://www.facebook.com/photo.php?fbid=1405969189641021&set=a.1384034005167873.1073741827.1384015488503058&type=1&relevant_count=1

...tt seems that ANY attitude control manoeuvre with the thrusters would impart translational velocity to the spacecraft in the 'forward' direction (with respect to the LAM).


Do any other spacecraft have such a construction of their RCS jets?




Also, I'm interested in working out the required delta-v that would've allowed the LAM to be used instead of these thrusters - especially because firing 8 jets such that only one component of the reaction force from each jet contributes to the total force on the S/C with the other cancelled by an opposite jet ... is an inefficient ....propellant wise..


https://www.facebook.com/photo.php?fbid=1405439613027312&set=a.1384034005167873.1073741827.1384015488503058&type=1&comment_id=83418&offset=0&total_comments=76
So there's a curve, factoring in the transient time of the LAM startup (and other engineering constraints on the minimum fire time..), the delta-v required (variable), and the angle of cant of the RCS jets (constant).


I'm wondering.. if the shape of this curve wouldn't have offered a more fuel efficient TCM, wherein they allow the required correction to build to a level, and then use the LAM.

https://www.facebook.com/photo.php?fbid=1405718662999407&set=a.1384034005167873.1073741827.1384015488503058&type=1&permPage=1
« Last Edit: 12/12/2013 04:36 AM by AJA »

Offline akula2

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Yes, but @Mangalyaan1 is not an ISRO account as far as I can tell. Don't know about India in Space.
I'm not registered (only use them for corporate presence/support) on Twitter or FB, yet those twitter handles shed some info so it's kinda complementary to FB.

Something is better than nothing  :)
 

Offline vyoma

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Yes, but @Mangalyaan1 is not an ISRO account as far as I can tell. Don't know about India in Space.
I'm not registered (only use them for corporate presence/support) on Twitter or FB, yet those twitter handles shed some info so it's kinda complementary to FB.

Something is better than nothing  :)

ISRO issued a press release about their official and various unofficial social media outlets:
http://www.isro.org/pressrelease/scripts/pressreleasein.aspx?Dec16_2013

As of now, ISRO MOM Facebook page is the only official page. Looks like they will be coming up with official social media presence for ISRO as a whole, as well:
https://www.facebook.com/isromom/posts/1407695689468371

Offline akula2

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@their official and various unofficial social media outlets

That press release makes no sense because it goes against the spirit of sharing knowledge. Example, Curiosity mission.

Anyway, it's nothing usual because last year I faced some hiccups while conducting feasibility on private partnership (my 4th company will be based in India/USA/Russia). The 'Raj' attitude and Red tape at many organizations must be shred. I hope the current AAP winds blow over the Southern states.

Offline hop

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That press release makes no sense because it goes against the spirit of sharing knowledge. Example, Curiosity mission.
It's clear that a fair number of people were confused by those unofficial accounts. I saw BBC quote the Mangalyaan1 twitter as if it were an official source, for example.

Clarifying which accounts are actually controlled by ISRO does not go "against the spirit of sharing knowledge", it helps people evaluate the sources.

Fan accounts are great, but it's in everyone's interest to distinguish them from actual sources inside the mission. This situation only arose because some of the unofficial accounts were (whether intentionally or not) easily mistaken for an official account. NASA has also gone after fan accounts which they thought were easily confused with official ones.

Offline vyoma

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Few updates on ISRO MOM:
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“The Mars orbiter was more than four million km away as of yesterday. The spacecraft is in good health,” he said on Tuesday from Bangalore. Every day, precision ranging of the spacecraft was being done to know where exactly it was and how far away it was. Ground controllers from the ISRO Telemetry, Tracking and Command Network (ISTRAC) in Bangalore, and the Indian Deep Space Network (IDSN) at Byalalu, near Bangalore, were communicating with the spacecraft.

Since the Mars spacecraft had travelled more than four million km away, “there is a communication delay of 12 seconds” each way, Dr. Radhakrishnan said.

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The orbiter “is in a parabolic trajectory around the sun towards Mars” said Deviprasad Karnik, ISRO spokesperson. The spacecraft had to be “seen” continuously, that is, it should be monitored all the time. So ground controllers from ISTRAC and IDSN were communicating with it.

As of now, the ground controllers at the IDSN were communicating with the spacecraft, using the dish-antenna with a diameter of 18 metres. From April 2014, they would use the 32-metre antenna to keep a tab on it, Mr. Karnik said.

http://www.thehindu.com/sci-tech/science/mars-orbiter-well-on-its-way/article5471052.ece

Offline jcm

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Few updates on ISRO MOM:
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The orbiter “is in a parabolic trajectory around the sun towards Mars” said Deviprasad Karnik, ISRO spokesperson. The spacecraft had to be “seen” continuously, that is, it should be monitored all the time. So ground controllers from ISTRAC and IDSN were communicating with it.
 
http://www.thehindu.com/sci-tech/science/mars-orbiter-well-on-its-way/article5471052.ece
I really hope it's in an elliptical trajectory, not a parabolic one
« Last Edit: 12/18/2013 11:29 PM by jcm »
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