Posts Tagged ‘MOM’

Five Mars orbiters observe from cover as Comet Siding Spring approaches Mars

October 16, 2014

Mars is a crowded place these days and is soon to get another, high-speed, transient visitor.

Comet Siding Spring (C/2013 A1) is approaching Mars and will pass within about 87,000 miles (139,500 kilometers) on Sunday 19th October.

Siding Spring’s nucleus will come closest to Mars around 11:27 a.m. PDT (2:27 p.m. EDT), hurtling at about 126,000 mph (56 kilometers per second). This proximity will provide an unprecedented opportunity for researchers to gather data on both the comet and its effect on the Martian atmosphere. 

Siding Spring came from the Oort Cloud, a spherical region of space surrounding our sun and occupying space at a distance between 5,000 and 100,000 astronomical units. It is a giant swarm of icy objects believed to be material left over from the formation of the solar system.

Siding Spring will be the first comet from the Oort Cloud to be studied up close by spacecraft, giving scientists an invaluable opportunity to learn more about the materials, including water and carbon compounds, that existed during the formation of the solar system 4.6 billion years ago.

Currently NASA has three craft in orbit around Mars (Odyssey, MRO and MAVEN), the European Space Agency has MEX and the Indian Space Research Organisation has MOM. In addition there are two active rovers on the surface of Mars; Opportunity and Curiosity. All the orbiters face a small risk of damage – not so much from Comet Siding Spring itself but from its long dust tail.  The rovers are not considered to be at significant risk since they will be protected by the Martian – albeit very thin – atmosphere. They have been moved to positions to observe.

SkyandTelescope: Such a close encounter means the dust tail left in C/2013 A1’s wake might graze Mars’s upper atmosphere. The smallest particles are only about a half millimeter across, but even these could severely damage a spacecraft when striking at 35 miles per second. Scientists predict that the time of greatest danger for the orbiters will occur about 90 minutes after Comet Siding Spring’s closest approach and last about 20 minutes. 

The three NASA Orbiters and ESA’s MEX have re-positioned themselves and will take shelter on the far side of Mars as the comet flies past. The Indian MOM has very little fuel to expend for any major changes to its orbital path and will just try to get as far away from the dust tail as possible and keep its antennae crossed.

To avoid the threat of Siding Spring’s debris, NASA engineers will manipulate the orbiters’ trajectories so that all three will end up on the opposite side of the planet during the flyby. The MRO team executed one maneuver at the beginning of July, with another planned for the end of August. The Mars Odyssey team took similar steps on August 5th, and the MAVEN team will perform a precautionary maneuver shortly after the spacecraft enters orbit around Mars.

Mars Orbiters 'Duck and Cover' for Comet Siding Spring Encounter

Mars Orbiters ‘Duck and Cover’ for Comet Siding Spring Encounter – NASA

MEX is following the same strategy

The European Space Agency is taking similar precautions to protect its Mars Express (MEX) orbiter. MEX has a highly elliptical orbit that would leave it exposed to Siding Spring’s debris longer than MRO or Odyssey. On June 22nd the MEX team altered the orbiter’s track around the planet so that it will be hidden behind Mars for 27 minutes during the comet’s closest approach.

ISRO’s MOM will not be behind Mars when the comet makes its closest approach to the planet. They do not have the fuel to expend and so will just try and be as far away as possible.

Hindustan Times: We have repositioned the Mars Orbiter, as the comet Siding Spring is expected to be close to the Mars on October 19. We have taken the Orbiter to a position farthest from the tail of the comet so that it doesn’t affect the satellite,” AS Kiran Kumar, director, Space Application Centre, Ahmedabad, said.

Fortunately the latest estimates have reduced the risk of collision somewhat:

ESA: Initial estimates gave the possibility that Mars Express might have to contend with a large particle flux – and that several (2? 3?) very high-speed (~56 km/sec!) particles might bash into the spacecraft. Happily, additional observations by ground and space telescopes (including the ESA/NASA Hubble Space Telescope) have allowed initial estimates to be refined and the risk is now understood to be much lower – and perhaps even as low as zero.

MOM’s first image from Mars

September 25, 2014

ISRO has released the first image taken by MOM on Mars.

Taken from a height of 7300 km; with 376 m spatial resolution.

Shades of pink and brown, but I am not sure why the lighter shades around each crater reminds me of gas bubbling through sand. The “streaks” in the bottom right quadrant are suggestive of “wind effects” in a sea of sand.


MOM orbit exactly as planned with a flawless MOI

September 24, 2014

ISRO can feel very satisfied. The MOI was flawless. The tracking indicates that the MOM has achieved an orbit of 421.7 km / 76993.6 km compared to the planned 423 km / 80,000 km. Not bad after a 10 month journey of some 680 million km. The inclination of orbit with respect to the equatorial plane of Mars is 150º and exactly as planned. 

The first colour pictures of Mars from MOM are expected within a day or two.

Now for a manned, fast, free-return, fly-by of Mars in 2018?

ISRO: India’s Mars Orbiter Spacecraft successfully entered into an orbit around planet Mars today morning (September 24, 2014) by firing its 440 Newton Liquid Apogee Motor (LAM) along with eight smaller liquid engines. This Liquid Engines firing operation which began at 07:17:32 Hrs IST lasted for 1388.67 seconds which changed the velocity of the spacecraft by 1099 metre/sec. With this operation, the spacecraft entered into an elliptical orbit around Mars. 

The events related to Mars Orbit Insertion progressed satisfactorily and the spacecraft performance was normal. The Spacecraft is now circling Mars in an orbit whose nearest point to Mars (periapsis) is at 421.7 km and farthest point (apoapsis) at 76,993.6 km. The inclination of orbit with respect to the equatorial plane of Mars is 150 degree, as intended. In this orbit, the spacecraft takes 72 hours 51 minutes 51 seconds to go round the Mars once.

Spaceflight101Launched back on November 5, 2013 atop a Polar Satellite Launch Vehicle, the Mars Orbiter was constrained by the performance of India’s workhorse launcher that required the spacecraft to take the scenic route – first entering an elliptical Earth orbit that the spacecraft raised by making six engine burns before firing its main engine, the Liquid Apogee Motor, a seventh time to depart Earth and enter a path to Mars on November 30. ….. 

The Mars Orbit Insertion Burn had a planned change in velocity of 1,098.7 meters per second with an anticipated burn time of 24 minutes and 14 seconds. However, engine shutdown was triggered by the navigation system when accelerometers sensed that the proper delta-v was achieved, dynamically adjusting for actual engine performance by extending of shortening the burn slightly. 

For MOM, the sun came up 19.5 minutes into its burn, but Earth was not coming into view until three minutes after the scheduled end of the Mars Orbit Insertion burn. The spacecraft was programmed to start the re-orientation back to its comm attitude one minute after shutdown, followed five minutes later by the re-activation of the communications system when MOM was visible from Earth again.
The Mars Orbit Insertion Burn had a planned change in velocity of 1,098.7 meters per second with an anticipated burn time of 24 minutes and 14 seconds. However, engine shutdown was triggered by the navigation system when accelerometers sensed that the proper delta-v was achieved, dynamically adjusting for actual engine performance by extending of shortening the burn slightly. 
For MOM, the sun came up 19.5 minutes into its burn, but Earth was not coming into view until three minutes after the scheduled end of the Mars Orbit Insertion burn. The spacecraft was programmed to start the re-orientation back to its comm attitude one minute after shutdown, followed five minutes later by the re-activation of the communications system when MOM was visible from Earth again.

MOM successfully enters Mars orbit – first time ever on a maiden Mars mission

September 24, 2014

In what appears to have been a remarkably flawless and precise operation ISRO’s MOM has entered Mars orbit. It is the first time that a country has succeeded to get a spacecraft to enter Martian orbit on its maiden attempt.

“We have the signal.

1099 m/s.

Expected – 1098.7 m/s”

(The Mars Orbit Insertion burn had a planned duration of 24 minutes and 14 seconds, slowing the spacecraft down by 1,098.7 meters per second to be captured in an elliptical orbit around Mars.)

The operations took place while the spacecraft was behind Mars. It seemed an endless wait for it to reappear. It was then a seemingly endless 12.5 minutes from when telemetry was reactivated and the signals were received confirming that the maneuvers had been successful.

The precise orbit achieved now awaits further tracking information.


Prime Minister Narendra Modi arrived at ISRO in time to witness the critical and historical phases of the orbit insertion procedures (and he is to be highly commended for preferring real things to the meaningless, pointless and futile climate change talkshop at the UN).

He was more than a little pleased.

Narendra Modi at ISRO after MOM achieved orbit — screen grab by The Hindu

A major step not just for India’s confidence in its technological capabilities but also for its geopolitical positioning against China.

BBC: If all goes well and the satellite orbits the Red Planet, India’s space agency will become the fourth in the world after those of the United States, Russia and Europe to undertake a successful Mars mission. …..

…… After India’s successful unmanned Chandrayaan mission to the Moon in 2008 that brought back the first clinching evidence of the presence of water there, the Mars mission, according to K Radhakrishnan, chairman of the Indian Space Research Organisation (Isro), is a “natural progression”. …….

India sees the Mars mission as an opportunity to beat its regional rival China in reaching the planet, especially after a Russian mission carrying the first Chinese satellite to Mars failed in November 2011. Japan also failed in a similar effort in 1998.

China has beaten India in space in almost every aspect so far: it has rockets that can lift four times more weight than India’s, and in 2003, successfully launched its first human space flight which India has not yet embarked on. China launched its maiden mission to the Moon in 2007, ahead of India.

So if India’s mission succeeds, it will have something to feel proud about.

Culmination nears for India’s Mars Orbiter Mission

September 23, 2014

In 8 hours – if everything goes as planned – the MOM would have been inserted into Mars orbit of 423 km at periareion and 80,000 Kilometers at apoareion  at an inclination of 150 degrees and with an orbital period of a little more than three days. Though a number of experiments are planned, the most important objectives of the mission – to demonstrate technology and capability – will largely have been accomplished on getting into orbit.

Frugal engineering and with a cost of about 10% of that of NASA’s MAVEN will have taken ISRO’s MOM into Mars orbit – and at the first attempt.

But the next few hours will be tense and nervous not only for ISRO mission staff but for the many millions of Indians who will be following the live webcast at The critical operations will take place while the MOM spacecraft is occluded on the far side of Mars and when signals will be taking over 12 minutes to reach earth.


The critical Mars Orbit Insertion Burn Sequence will begin three hours ahead of the planned maneuver time when the spacecraft automatically switches over to its Medium Gain Antenna for communications since the High Gain Antenna will be pointing away from Earth during the retrograde burn.
21 minutes ahead of ignition, the spacecraft will begin the re-orientation to the proper attitude for the burn, pointing LAM to the direction of travel. The re-orientation is accomplished using the vehicle’s Reaction Wheels. Five minutes and 13 seconds ahead of the burn, the spacecraft passes into darkness – for the first time since leaving Earth last year. In advance, MOM will fully charge its battery to be in a safe configuration for the eclipse.
Three minutes ahead of the burn, the vehicle’s eight 22-Newton thrusters are enabled to start providing attitude control which they will continue to do throughout the main engine burn, keeping MOM pointing forward. Ignition of the Liquid Apogee Motor is planned at 1:47:32 UTC on Wednesday, September 24, 7:17 Indian Standard Time. The Mars Orbit Insertion burn has a planned duration of 24 minutes and 14 seconds, slowing the spacecraft down by 1,098.7 meters per second to be captured in an elliptical orbit around Mars. During the burn, the engines will consume 249.5 Kilograms of propellant leaving only about 40 Kilograms of propellant for the rest of the mission.
Should something go wrong during the burn, MOM is programmed to react appropriately in order to achieve a stable orbit around Mars – even if that means to spend all the vehicle’s propellant to do so. In the event the Liquid Apogee Motor is not ignited or its burn is cut short, MOM would automatically switch to the 22-Newton thrusters to supply as much delta-v as possible. Due to their lower thrust, the 22N thrusters would need to fire much longer than LAM along a greater stretch around the periapsis pass which will increase propellant consumption and leave MOM in a higher orbit.
MOI timeline

Graphic ISRO (via spaceflight101)

MOM test fires liquid motor for orbit insertion on Wednesday

September 22, 2014

A sigh of relief today as the liquid fueled motor was successfully test fired for 4 seconds after having last been used 9 months ago.

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.

The MOM is now in (or just entering) Mars’ sphere of influence and is effectively falling freely towards Mars. The orbit insertion procedure is described here.

Mars Orbit Insertion for MAVEN and MOM

graphic: indiaspaceactivity

On 24th 0127 GMT, even as it is falling with speed of 4 kms/sec, the craft is reoriented so that the thrusters face forward  ( for the next orbit maneuver of retro thrust to reduce the speed and to direct it in the required orbit ). The re-orientation is completed @ 0147 GMT. MOM would by this time be falling with a speed of  4.48Km/sec.

After the disturbances due to reorientation have died, i.e. 5 seconds later,  the Retro action starts with the firing of  LAM using 8 thrusters ..  the fall speed by now is 4.68 km/s. Even as the thrusters start their effort to reduce the speed of MOM, the fallingspeed continues to increase due to the gathered momentum upto 5.89 km/s and thenspeed  starts falling. The LAM firing also directs the craft in the desired direction so that it achieves the required orbit around Mars. The LAM operation ends @0216GMT.

As shown in figure there the MOM speed would increase from 3.18 Kms/sec to 5.89Kms/sec @  0216GMT.

Now notice that MOM approached Mars parellel to  equator unlike MAVEN which approached over North pole.  The reason for these two approaches is that the final orbits of MAVEN and MOM are inclined @ 75 deg and @ 19 deg respectively. This is evident from the ‘ cross roads ‘ seen between MOM and MAVEN release in the combination diagram shown above.

In the above flow of sequence we did not have time to  mention a couple of more chilling facts: @ nearly the same time when LAM operation starts MOM would go behind Mars as seen from Earth. Secondly , even if it was visible, whatever happens at MOM will be known to Earth only after 12 minutes due to the distance between Earth and MOM. So all this (and next described operations ) are being done under the unsupervised pre-loaded command sequences. So the success indicates how well are we in anticipating the situation through modelling.

A detailed look at dynamics of acceleration during this critical operation is shown in this graphic. (numbers are in kms/sec/sec ) corrosponding to sky blue curve. (X axis is time axis from 0110GMT to 0310GMT of 24 Sep. )
Violet curve is the speed normalized to fit in this graph with that of acceleration. Actual speed variation shown corresponds to 3.88 km/sec at left to 5.89km/s at peak near center which falls to 4 km/s at lsft edge.

We have also marked the events of reorientation (between red dots) and retro rocket firing (between Green dots ) on acceleration curve.

Notice that the LAM retro action started at first green dot on left ( 0152 GMT ) ..  it has tried to reduce the speed but the fall is more powerful, so MOM speed continues to increase despite retro action. This continues and for sometime eventhough the acceleration has started reducing ( blue line coming down ), the gathered momentum  makes the craft to increase its speed for sometime. Finally however the thrusters succeed in reducing the speed ( reversal near center of violet line ) ..  the thrusters are also turned off at that moment.(green dot near the center of graph ). Now the total operation of MOI is over.

Incidentally, the point where speed reversal has taken space forms the lowest point near the surface of MOM prior to first perigee which would occur after the craft completes one revolution.

Maven to enter Mars orbit tonight and MOM on Wednesday

September 21, 2014


NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft successfully entered Mars’ orbit at 10:24 p.m. EDT Sunday, Sept. 21, where it now will prepare to study the Red Planet’s upper atmosphere as never done before. MAVEN is the first spacecraft dedicated to exploring the tenuous upper atmosphere of Mars.


NASA’s Maven will be inserted into Mars orbit later tonight at 2130 pm Eastern time and will be covered live by NASA TV.

India’s MOM should be inserted into Mars Orbit on Wednesday.

(Related: Alternate paths to Mars: NASA’s MAVEN compared to India’s MOM)

Maven planned Mars orbit insertion 20140921 - NASA

Maven planned Mars orbit insertion 20140921 – NASA

The orbit insertion factsheet from NASA is here: MAVEN Orbit Insertion Fact Sheet – NASA

The orbit-insertion maneuver will begin with the brief firing of six small thruster engines to steady the spacecraft. The engines will ignite and burn for 33 minutes to slow the craft, allowing it to be pulled into an elliptical orbit with a period of 35 hours.

Following orbit insertion, MAVEN will begin a six-week commissioning phase that includes maneuvering the spacecraft into its final orbit and testing its instruments and science-mapping commands. Thereafter, MAVEN will begin its one-Earth-year primary mission to take measurements of the composition, structure and escape of gases in Mars’ upper atmosphere and its interaction with the sun and solar wind….

MAVEN launched Nov. 18, 2013, from Cape Canaveral Air Force Station in Florida, carrying three instrument packages. It is the first spacecraft dedicated to exploring the upper atmosphere of Mars. The mission’s goal is to determine how the loss of atmospheric gas to space played a role in changing the Martian climate through time.

ISRO’s press briefing for the MOM Mars orbit insertion is here: MOM press briefing on Mars Orbit Insertion

MOM Mars Orbit insertion planned for 20140924  ISRO

MOM Mars Orbit insertion planned for 20140924 ISRO

MOM and MAVEN approach Mars

August 12, 2014

Both the Indian Mars Orbiter Mission (MOM – Mangalyaan, budget $70 million) and NASA’s MAVEN (budget $672 million) are now approaching Mars. Both are doing well according to their latest status updates.

MOM was launched on 5th November last year and MAVEN on 18th November, 2013. Whereas MAVEN on its Atlas 5 rocket could directly enter into a  Hohmann Transfer Orbit with periapsis at Earth’s orbit and apoapsis at the distance of the orbit of Mars, MOM had to take the low-cost, scenic route. Because of the relatively low payload capability of the PSLV launch rocket, MOM had to spend 26 days in ever-increasing earth orbits. MOM had to fire its Liquid Motor six times to work its way up to departing Earth orbit using a standard Hohmann Transfer Orbit on 1st December.

Alternate paths to Mars: NASA’s MAVEN compared to India’s MOM

MAVEN - MOM trajectories

MAVEN – MOM trajectories


When they were launched MAVEN was expected to reach Mars on 22nd September 2014 and MOM 2 days later on 24th September 2014. The time lines have shifted slightly subsequent to the mid-course corrections carried out and MOM is now expected to reach Mars orbit about a week ahead of MAVEN. I suspect that the time of Mars Orbit Insertion is still a little fluid, but both are about 1 month away. MOM is currently about 6 minutes away in radio signal distance.

Discovery News:

India’s Mars Orbiter Mission (MOM) is more than 80 percent of the way to Mars and performing well, according to a Facebook update posted July 21 by the Indian Space Research Organization. MOM is expected to enter orbit on Sept. 14.

The second craft, NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN), is also performing well. MAVEN is scheduled to embark on its final approach to the Red Planet on Sept. 21, one week after MOM’s arrival, principal investigator Bruce Jakosky said. After months of checkouts and tests, the spacecraft will now be left quiet until close to the big day.

NASA’s MAVEN has now gone into a “pre-Mars Orbit Insertion moratorium.” All systems required for a safe Mars Orbit Insertion remain powered on. But other systems like the instruments are shut down until late September because they are not needed for a successful MOI. We want the spacecraft system to be as “quiet” as possible and in the safest condition during the critical event on September 21st”.

Related: Frugal engineering for India’s Mars mission

100 days to Mars for ISRO’s Mangalyaan

June 16, 2014

Four days ago

  • The second Trajectory Correction Manoeuvre (TCM-2) of India’s Mars Orbiter Spacecraft was successfully performed on June 11, 2014 at 1630 hrs IST. TCM-2 was performed by firing the spacecraft’s 22 Newton thrusters for a duration of 16 seconds.
  • At present, the radio distance between the Spacecraft and the Earth is 102 million km. A radio signal from the Earth to the Spacecraft now takes about 340 seconds. The spacecraft so far has traveled a distance of 466 million km as part of its total Journey of 680 million km.
  • ISRO is continuously monitoring Mars Orbiter Spacecraft using Indian Deep Space Network (IDSN). The spacecraft and its five scientific instruments are in good health.

And 100 days from today on 24th September, ISRO’s frugally engineered  Mars Orbiter Mission (called Mangalyaan meaning Mars craft) should be inserted into Mars orbit. The highly over-rated movie “Gravity” had a larger budget at $100 million than ISRO’s $75 million for its Mars mission.

Heigh-ho, ISRO, it’s off to Mars we go

November 30, 2013


Trans-Mars injection has been completed successfully.

  • Trans Mars Injection (TMI) operations completed successfully. The liquid engine burn time was 1328.89 sec and the imparted incremental velocity was 647.96 m/sec.
  • Trans Mars Injection (TMI) operation began at 00:49 hrs (IST) on Sunday Dec 01, 2013.
  • Forward rotation of spacecraft, to put it into the right orientation to perform Trans Mars Injection (TMI) operation has been completed successfully at 00:30 hrs IST on Dec 1, 2013


A big night for ISRO and congratulations are due! And not least for ISRO’s coverage of the event – almost live – on their Facebook page. (I have not been too enamoured of the ISRO website but somebody did a great job on the live updates).

The Indian Mars Orbiter (Mangalyaansuccessfully completed its final burn in earth orbit and has been inserted into a Trans Mars Trajectory (to be confirmed). It may just be one small step in Man’s exploration of space but it is a giant leap for ISRO. After spending a month in 6-ever increasing orbits around Earth the craft now has a 300 day journey to get to Mars with the possibility of 3 mid-course corrections before the liquid engine has to be fired up again to enter into orbit around Mars.

So far, so good!

A number of “firsts” for the Indian Space Research Organisation (ISRO) and, no matter what may now happen, a great many accomplishments already in the bag. The lack of a sufficiently powerful rocket necessitated that the craft first enter earth orbit and then the month-long, laborious compared to NASA, procedures where the space craft engine had to be used  to first to increase the earth orbits and then – tonight – be fired for an extended time (23 minutes) to be inserted into a heliocentric Trans Mars Trajectory.

Mission Operations Complex ISTRAC  Bangalore.

Mission Operations Complex ISTRAC Bangalore.


One hour before the final engine firing the craft was put under the control of its on-board computer which was to carry out the final burn. Forward rotation of the spacecraft to put it into the right orientation for the burn was carried out and completed about 20 minutes before firing. Engine firing started on schedule just before the craft reached perigee. The actual burn of the 440 N Liquid Engine lasted its planned 23 minute long firing entirely under local on-board computer control. The objective was to impart an incremental velocity of 648 m/s and the indications are that that was achieved. The engine firing manoeuver seems to have gone exactly to plan. The orbit determination team have now to confirm now confirmed the trajectory actually achieved.

The new heliocentric orbit is yet to be confirmed. confirmed

The ISRO chorus (with apologies to Walt Disney)

Heigh-ho, ISRO

It’s off to Mars we go

We keep on working all day long

Heigh-ho, ISRO 

Photo: Liquid Engine propels MOM into Mars Transfer Trajectory and India into interplanetary space !Trans-Mars injection has been completed successfully.

Liquid Engine propels MOM into Mars Transfer Trajectory and India into interplanetary space !Trans-Mars injection has been completed successfully. ISRO


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