Mangalyaan: ISRO's Mars Orbiter Mission

alexis · Post by **alexis** » 22 Sep 2014 15:51

chaanakya wrote:Congratulations ISRO for sterling success. India will be fourth after US, Russia and EU Space Agency to achieve this success and FIRST ASIAN Country to do so. It will be also the FIRST to achieve this success in first try. So far 51 Mission have been launched and 21 are only successful.

Zee TV had continued coverage. DD had some. Rest were bottom Breaking News. Apparently this is not a big achievement to be worthy of coverage of decent duration by MSM.

hecky ji , Only Dilbu is BRF's Official Anti Jinx Wizard.

This is an event only for jingos. MSM will get interested only on 24th when actual insertion is carried out.

I have a question - due to this test firing, the velocity of MOM would have changed, right? To what extent?

Neela · Post by **Neela** » 22 Sep 2014 16:04

alexis wrote:
This is an event only for jingos. MSM will get interested only on 24th when actual insertion is carried out.

I have a question - due to this test firing, the velocity of MOM would have changed, right? To what extent?

Let me pile up on this. Did MOM re-orient and test fire the engine? Is the new v now lesser than what it was few hours back?

Comer · Post by **Comer** » 22 Sep 2014 16:12

Just read an interview with ISRO chief in The Hindu in which says delta v is 2.14 m/s post 4 seconds and I guess no reorientation

http://www.thehindu.com/sci-tech/scienc ... 431827.ece

pankajs · Post by **pankajs** » 22 Sep 2014 16:42

Engine test success

Thakur_B · Post by **Thakur_B** » 22 Sep 2014 16:42

Dilbu wrote:MOM will fail onlee.

Dilbu's jinx zindabad

KrishG · Post by **KrishG** » 22 Sep 2014 17:01

Neela wrote:
alexis wrote:
This is an event only for jingos. MSM will get interested only on 24th when actual insertion is carried out.

I have a question - due to this test firing, the velocity of MOM would have changed, right? To what extent?
Let me pile up on this. Did MOM re-orient and test fire the engine? Is the new v now lesser than what it was few hours back?

Nope. Reorientation will occur before the final firing. It's velocity will be slightly (very slightly) more than it was before. The firing was mainly to test the engines and to alter the path by a little so that it will be 500km from the Martial surface when MOI will begin instead of the 700 odd km if the correction hadn't been done today.

Comer · Post by **Comer** » 22 Sep 2014 17:12

^^ yes. The delta v for 4 second firing vs the prolonged firing on 24th(around 1.5 m/s) should be the indicator for reorientation or not.

SwamyG · Post by **SwamyG** » 22 Sep 2014 17:36

Dil maange Dilbu more. Go ISRO...

member_28108 · Post by **member_28108** » 22 Sep 2014 17:55

KrishG wrote:
saravana wrote:Isro page says 4am
Basically there will be a window of a few hours within which orbital insertion can take place. The exact time at which LAM starts firing will be left to ISRO to decide.

We do NOT have a few hours! It is tightly choreographed sequence. The time line has been posted by ISRO to the last second
I had posted it previously. Add 12 minutes to get IST.

shravanp · Post by **shravanp** » 22 Sep 2014 18:07

Great news! Woke up twice in night to check on forums. Finally in the morning, I read that the LAM test went off smoothly.

juvva · Post by **juvva** » 22 Sep 2014 18:12

KrishG wrote:
Neela wrote:
Let me pile up on this. Did MOM re-orient and test fire the engine? Is the new v now lesser than what it was few hours back?
Nope. Reorientation will occur before the final firing. It's velocity will be slightly (very slightly) more than it was before. The firing was mainly to test the engines and to alter the path by a little so that it will be 500km from the Martial surface when MOI will begin instead of the 700 odd km if the correction hadn't been done today.

Looks like there was no change over to medium gain antenna, no reorientation ( by 180 degrees ) - both will be done for MOI burn.
Even though there was no drastic (180 degrees) reorientation, there must have been a attitude change to point the probe at the corrected trajectory.

chetak · Post by **chetak** » 22 Sep 2014 18:13

chaanakya wrote:Congratulations ISRO for sterling success. India will be fourth after US, Russia and EU Space Agency to achieve this success and FIRST ASIAN Country to do so. It will be also the FIRST to achieve this success in first try. So far 51 Mission have been launched and 21 are only successful.

Zee TV had continued coverage. DD had some. Rest were bottom Breaking News. Apparently this is not a big achievement to be worthy of coverage of decent duration by MSM.

hecky ji , Only Dilbu is BRF's Official Anti Jinx Wizard.

Recognised, verified and validated Anti Jinx Wizard. Lets all hope that Dilbu ji has also been revalidated and is current.

harbans · Post by **harbans** » 22 Sep 2014 18:23

For those that want to watch the event, this is from ISRO:

After the test firing today, the orbit insertion will be an autonomous function. The commands were successfully fed in last week itself.

Ashokk · Post by **Ashokk** » 22 Sep 2014 18:30

Mangalyaan will send colour images of Mars from Wednesday

BANGALORE: Following the successful re-firing of the main liquid engine of the Mars Orbiter Mission (MOM) spacecraft for a minor trajectory change on Monday, Isro is planning to activate the colour camera payload and get the first images of the red planet by Wednesday afternoon.

With Monday's success, the possibility of MOM acquiring the desired orbit around Mars on Wednesday has reached near 100 per cent. With respect to this, scientific secretary V Koteswara Rao told TOI: "Soon after the Mars orbit insertion operations on Wednesday is complete and things settle down, we will have the images transmitted back to earth. We are looking at afternoon."

Victor · Post by **Victor** » 22 Sep 2014 18:39

From what I gather, the reaction wheels on Mangalyaan can reorient the spacecraft about its center of mass by relying only on electric power generated by its solar panels. I am curious to know why they are not being used to reorient before the main burn, which would save fuel. Or are they being used in tandem with the thrusters.

RonyKJ · Post by **RonyKJ** » 22 Sep 2014 18:45

I wonder if the color camera can be set to continuously stream images as MOM passes over the planet.
It would be great to watch these images live as a webcast

Victor · Post by **Victor** » 22 Sep 2014 18:51

ashokk wrote:Mangalyaan will send colour images of Mars from Wednesday
.. With Monday's success, the possibility of MOM acquiring the desired orbit around Mars on Wednesday has reached near 100 per cent..

I also feel this is true but this kind of advance horn-tooting makes me nervous. It is a bad habit that needs to be erased. Now we need Dilbu mia's anti jinx in double strength.

Amber G. · Post by **Amber G.** » 22 Sep 2014 19:28

tushar_m wrote:Wo sab theek hai , par mileage kitna deti hai ?

Better than rickshaw which gives INR 15 per km.

Enjoyed the image... (Specially found it interesting that something similar was posted here about a week ago..

http://forums.bharat-rakshak.com/viewto ... 8#p1717158

Amber G. wrote:Seeing this (see picture below) brought two thoughts..

1. The sign is little more positive than usual ("muh Kala") and IMO more apt.

2. The charge this auto-riksha charges is about the same (just a little higher) than MOM is spending..
(about 11 Rs/Km - Not bad if you ask me- for about 680Km - journey)

picture

SwamyG · Post by **SwamyG** » 22 Sep 2014 19:39

Answers to some of the earlier questions

Isro used 564g of fuel to re-fire the engine for about 4 seconds (3.986 seconds), which achieved a trajectory correction by reducing the speed by 2.18 metre per second. The spacecraft is currently travelling at a speed of 22-km per second. It would have to be reduced drastically to 1.6-km/second so as to be inserted into the martian orbit.

http://economictimes.indiatimes.com/new ... 163036.cms

SaiK · Post by **SaiK** » 22 Sep 2014 19:47

Yahoo! we are the 3rd nation after maasans and yews.

^#rickshaw model: it would be cheaper now to go Jupiter then.

Amber G. · Post by **Amber G.** » 22 Sep 2014 19:53

symontk wrote:
But won't the MARS path will be along the sun's equatorial path like earth or is it an tilted path around sun?

Just to be clear, both Mars and earth's paths around the sun, though roughly on the same plane but are not on the sun's equatorial plane. Sun's equatorial plane is about 7.25 degrees tilted to the ecliptic plane (and about 67.23 degrees to galactic plane ). Both earth and Mars move, more or less, in ecliptic plane ..(Mar's orbit is a little more tilted (about 1.8 degrees) to ecliptic than the earth's(nearly zero).

Small point of interest, coincidence - always fascinated me. Both Earth's and Mars day is about 24 hours, and both are tilted wrt to ecliptic about the same, so will have similar pattern of weathers. (Mars is 25 degrees, compared to Earth's 23.5 degrees). Mar's north pole also points to bright Deneb.

symontk · Post by **symontk** » 22 Sep 2014 20:05

Thanks, that's good information

Amber G. · Post by **Amber G.** » 22 Sep 2014 20:12

ravar wrote:
Amber G. wrote:>>Interesting to note that ISRO chose MOI with MangalyAn in the blind i.e., from T +5 to T+ 30.43 minutes, there is NO telemetry.

Newbie question- is there any option of recording the data by the spacecraft during the blind period and transmitting it back once the telemetry resumes? (ISRO can surely use the data to fine-tune its simulation models in future) TIA.>>>

Indeed one of the primary mission objective is to record that data and send it to earth and analyze it for future. (Rest assured, many routine things, eg good photographs of known objects with the background of stars - to pinpoint position, etc will be sent too)

BTW, "blind or not blind" makes no difference here. MOM must be able to act and depend on it's own computer as the radio delay time is about 12 MINUTES. .. (It will take about 24 minutes for roundtrip of radio signal !)
Amber ji, thanks for the reply.

But I believe there is a crucial difference. In the event of MAVEN not making its MOI properly (i.e., crashing onto Mars), NASA will be able to get all the data until the last moment that telemetry is possible of what went wrong since they are not in the blind. They will have a good learning curve even if their MOI is a failure.

Obviously, this luxury is not available to ISRO since they are in the blind during MOI. If something wrong happens, they will not have access to the crucial data to fine-tune another MOI for MangalyAn-2.

IOW, we will have MOI data only if MOI is successful. Am I right?

Try to answer, what I think you are asking. Hope this is helpful.
First - "Fail" here most likely is engines not working. Chances of MOM "crashing" (or getting lost if the engines do not fire) is obviously extremely low. MOM will be sending all the data after a blind period of about half an hour if all goes well, a little sooner if engines do not fire.

(Part we are worried about is, if systems fail, no power, antena fails to direct towards earth etc.)

In any case, it will take lot of time.. (days or may be weeks) to send all the collected data at MOI (buffered and stored locally on MOM and transmitted to earth, taking its own time)... so in that in that regard MAVEN has no advantage over MOM.

Amber G. · Post by **Amber G.** » 22 Sep 2014 20:29

A interesting equation for those who want to do their own calculations..

To calculate delta-V, (forget about all the fine details.., as long as you know fuel burned - and exhaust velocity.)..

delta-V = (exhaust velocity)* natural log of ((total mass ,with the fuel)/(remaining mass, after fuel is gone))

sanjaykumar · Post by **sanjaykumar** » 22 Sep 2014 20:57

Interesting, why is it natural log? (i.e. what is the principle behind the equation?). Thanks.

Amber G. · Post by **Amber G.** » 22 Sep 2014 21:02

Okay, in my opinion, the single most important/crucial part, which no newspaper seem to have mentioned.. and even Dilbu's anti-jinx did not touch ....

I want to see, if the engineers who designed those accelerometers earned their pay or not. (If things go well, brf should award them its highest honor).

A few posts ago, in my reply to Sri-Kumar, I said that inertial systems are not playing major role in navigation part, but now it is all up to these systems.

Because when all is said and done... when MOM is on the "other side" of Mars, where it can not even see the earth.. when the rocket burn start..*only* thing which will control the burn is internal accelerometers. When they/it integrate the "a" over time, starting when the burn start, and reach the calculated delta-V as 1098 m/s, it will issue a command to shut down the fuel line.

So let all the anti-jinx part, for now, go towards the the accelerometer.

(For those who are history buffs, in old days (first Mars mission) the system was anolog. Integration was done by measuring total charge as accelerometer produced current proportional to "a" and integration was done by knowing that dq/dt = current. Now of coruse, the "integration" is done by digital computers.. which are much more accurate and cheaper)

Amber G. · Post by **Amber G.** » 22 Sep 2014 21:07

sanjaykumar wrote:Interesting, why is it natural log? (i.e. what is the principle behind the equation?). Thanks.

This is very well known "ideal rocket equation" ... first mentioned in 19th century by Tsiolkovsky.. but found in any good text book.

Amber G. · Post by **Amber G.** » 22 Sep 2014 21:13

RonyKJ wrote:I wonder if the color camera can be set to continuously stream images as MOM passes over the planet.
It would be great to watch these images live as a webcast

Would be nice, but with about 20W transmitter, even with a high gain antena, it may be a challenge:)
(For perspective, the local radio station I am listening is less than 10Km away, does not give picture - only music , is about 100,000 W)

If you mean web-cast from earth, even with the most powerful telescope, (even if we forget atmosphere which will fuzzy everything), we can not resolve/see MOM from earth.

Amber G. · Post by **Amber G.** » 22 Sep 2014 21:32

SSSalvi wrote:^^^

Here are details of how the orbits are inclined
Earth 0 deg
Mars 1.84 deg ( You may notice it in the diagram )
Maven ( HAD ) 2.04 deg
MOM 2.48 deg

You can imagine the Earth inclination in that diagram by noting the horizontal path ( undulations representing six orbits while raising the Earth orbit ) that MOM took before TMI ( Nov 2013 time tag )

Thanks. Very nice.

Can you (sorry if you have already done that in your blog) also use areocentric ( Mars centric coordinate system) for "zoom in"... since now this will be the most useful and interesting to most.

For example, MOM's orbit, will be/is tilted (according to isro's website) about 150.0 degrees ...
This is, IMO, the most important number - now that MOM will be in orbit of Mars.

(I have not played with Nasa eyes, so don't know if the coordinate change in areocentric system is included there or not)

SwamyG · Post by **SwamyG** » 22 Sep 2014 21:36

Great attitude by ISRO, from its tweets

"Test Firing of Liquid Engine: Guided by wisdom, Executed by youth"

member_28108 · Post by **member_28108** » 22 Sep 2014 21:39

from Emily Lakhdawala's Blog in Planetary society

http://www.planetary.org/blogs/emily-la ... eline.html

SwamyG · Post by **SwamyG** » 22 Sep 2014 21:39

duplicate....deleted.

member_28108 · Post by **member_28108** » 22 Sep 2014 21:42

RonyKJ wrote:I wonder if the color camera can be set to continuously stream images as MOM passes over the planet.
It would be great to watch these images live as a webcast

The buffer time would be stupendous as the data is huge but the transmission rate is slower and there is a 12 minutes lag.
If you see how the pictures by Viking, Curiosity etc are sent you will see how slowly the pixels fill up on the screen as it is being transmitted and caputured. It was shown in some program by Discovery channel.!

chetak · Post by **chetak** » 22 Sep 2014 21:59

prasannasimha wrote:

from Emily Lakhdawala's Blog in Planetary society

http://www.planetary.org/blogs/emily-la ... eline.html

Usual and expected jealous paki comment on Emily's blog

PakistaniIntellect: 09/21/2014 01:43 CDT
Indian mission is a LIE..India can not send a mission to Mars..Its all lie hahaha..We Pakistanis dont believe what u say...In Islam ,landing or orbiting a planet is called a SIN...India never sent any mission to Mars..I know that !!

Amber G. · Post by **Amber G.** » 22 Sep 2014 22:00

alexis wrote: I have a question - due to this test firing, the velocity of MOM would have changed, right? To what extent?

Sorry if answer is posted before. They used about half a kg of fuel, and delta-V was about 2 m/sec.. (happens to send MOM to a better point also- but that is not that important - a hundred Km this way or that way is not going to make much difference)..Main excitement is that system worked . so everything is ready for the main event, when fuel burn is MUCH larger and so will be velocity change.

SaiK · Post by **SaiK** » 22 Sep 2014 22:22

amber ji, what would be the window of "the other side of mars" that should only depdent on a? would we be still in the line of signal on the orbit away on the other side of sun anytime? tia

Amber G. wrote:Okay, in my opinion, the single most important/crucial part, which no newspaper seem to have mentioned.. and even Dilbu's anti-jinx did not touch ....

I want to see, if the engineers who designed those accelerometers earned their pay or not. (If things go well, brf should award them its highest honor).
..)

we should revisit on this thread to honor them (if).

Comer · Post by **Comer** » 22 Sep 2014 22:29

Amber G. wrote:
Because when all is said and done... when MOM is on the "other side" of Mars, where it can not even see the earth.. when the rocket burn start..*only* thing which will control the burn is internal accelerometers. When they/it integrate the "a" over time, starting when the burn start, and reach the calculated delta-V as 1098 m/s, it will issue a command to shut down the fuel line.

Amber G, I have a very noob question. why does it have to depend on this? Can't it be timer based? if all the parameters are known, like location, velocity etc, wouldn't it be fired based on elapsed time from say, t0?

Amber G. · Post by **Amber G.** » 22 Sep 2014 22:31

For the record and interest here. (Sorry if duplicate)

From isro>>>
Mars Orbiter Spacecraft's Main Liquid Engine Successfully Test Fired

The 440 Newton Liquid Apogee Motor (LAM) of India's Mars Orbiter Spacecraft, last fired on December 01, 2013, was successfully fired for a duration of 3.968 seconds at 1430 hrs IST today (September 22, 2014). This operation of the spacecraft's main liquid engine was also used for the spacecraft's trajectory correction and changed its velocity by 2.18 metre/second. With this successful test firing, Mars Orbiter Insertion (MOI) operation of the spacecraft is scheduled to be performed on the morning of September 24, 2014 at 07:17:32 hrs IST by firing the LAM along with eight smaller liquid engines for a duration of about 24 minutes.

Pre-MOI press briefing.. posted in brf before

Nice MOI simulation - posted in brf before

Some thoughts -
With successful test of LAM I think all should be VERY happy and hopeful that things will go fine.
(in my view, it was more of a binary pass/fail test- so if this worked I am much more confident that it will work)

For me, the kind of bad news now, will be things like reorientation of the space craft, or fail to reorient High gain antena etc (in that case we will not get the data back even if everything else works

).. but these things can happen any time...

BUT, I don't think isro guys are now worried about "real 30 minutes of terror" or things like that..If everything is not perfect, the orbit may be different than one intended but, in grand scheme of things.. SO WHAT? Even if orientation is not perfect, or rocket does not work perfectly, delta-V will still be okay to put MOM is some orbit and that is not going to be classified as a failure.

SaiK · Post by **SaiK** » 22 Sep 2014 22:36

saravana wrote: ..wouldn't it be fired based on elapsed time from say, t0?

what is t0? how do you define that?
ps: also how do you know you on mars orbit?

Comer · Post by **Comer** » 22 Sep 2014 22:44

^^ I am on shaky ground here, so bear with me. My understanding is, the position and velocity of MOM can be predicted at any point of time and so is the position at which the engine ought to be fired. t0 is any point before the engine firing, let us say before the communication blackout. Can't the engine be fired n seconds after t0, instead of using an accelerometer?