Mars Orbiter Mission (MOM) - Manglayaan

Mars Orbiter Mission - Manglayaan
Mars Orbiter Mission - Manglayaan. Photo Credit: ISRO


Introduction

 Total Weight (kg)  1,350
 Science Payload Weight (kg)  14.49
 Fuel Load (kg)      850
 Launch Date  November 5, 2013
 Trans Mars Injection  December 1, 2013
 Mars Orbit Insertion  September 24, 2014
 Planned Mars Orbit   Periapsis: 365-km, Apoapsis: 80,000 km, Orbital Period: Approx 77-hr

ISRO launched the 1,350 kg Mars Orbiter Mission - Manglayaan - from Sriharikota using PSLV-C25, an XL variant of the launcher, on November 5, 2013 at 14:38 hrs to avail of the November 2013 launch window for the planet. The launch was earlier scheduled for October 28, 2013, but was postponed to accommodate the delay in the arrival in South Pacific, due to bad weather, of one of the two SCI ships to be used for tracking the launch of the spacecraft.

ISRO was sent hurtling on a Mars intercept trajectory from earth orbit at 0.42 hours on December 1.

The Mars orbiter will be placed in an orbit of 372 x 80,000 km around Mars on September 24, 2014.

The spacecraft carries 14.49 kg of scientific payload on- board.

ISRO initially planned to use the GSLV to launch a 500 kg Mars orbiter with 25 kg scientific payload, but scaled down its plans because of two back to back failures of the launcher in 2010.

The GOI sanctioned seed money of Rs 10 crore in August 2009 to carry out studies on suitable experiments for the mission.

The budget for FY 2012-13 allocated Rs. 125 crore for the mission during the financial year. The union cabinet cleared the project on Friday, August 3, 2012.

MOM Launch Complexity

The MOM was launched nearly 25 days before the start of its journey to give mission planners sufficient time to raise its orbit before the opening of the Mars journey start window on November 27.

The lift off time slot varied each day starting November 5 with five minutes leeway.

Propelling the MOM accurately on a Mars intercept trajectory required a complex set of maneuvers during and after launch. Trajectory calculations were specific to the date of the launch; they had to be recomputed in case of any launch delay.

"The time of lift-off and required coasting duration is different for each day of launch; and one has to work out a series of different trajectory management strategies corresponding to each possible launch date," says V Adimurthy, professor at Satish Dhawan Space Center and senior adviser (interplanetary missions) of ISRO. [via The Economic Times] 

The spacecraft's orbital insertion involved long coasting of the rocket between third and fourth stage. 

"The management of the long coast between third and fourth stage is a complex issue," says Adimurthy. 

PSLV-C-25 was to inject the MOM into a 250 X 23000 km orbit with an inclination of 17.864 degree. The MOMS velocity was planned be progressively increased to the Earth escape velocity of 11 km per second using three to five burns of the MOM's Liquid Apogee Motor (LAM).

In order to minimize the energy requirement for the journey to Mars, the Argument of Perigee (AOP) of the MOM  needed to be between 276.4 deg to 288.6 deg, compared to 178 deg in earlier missions. (The AOP is the angle between the perigee of a earth satellite and its ascending node.)

The MOM launch flight regime was planned to last 2,657s, as against 1,200s for regular PSLV missions, with a  1,580-1,800s coasting before the ignition of the PS4 stage.
 
According to ISRO, the long coasting necessitated specific modification and validation of the coast phase guidance algorithm, on-board battery capacity augmentation, assessment on the performance of inertial systems for extended flight duration and deployment of two ship-borne terminals to capture the crucial telemetry data during flight in the non-visibility zone.
 
ISRO said that additional provisions were made for the thermal management of Vehicle Equipment Bay, PS4 stage and also the Spacecraft elements considering the longer exposure to extreme cold space.

The MOM's 55 million miles journey to Mars is expected take 300-days. Its trajectory would need to be accurate enough to bring it within 60 km of the Red Planet on September 24, 2014 to ensure successful Mars capture. 

MOM will be travelling at a velocity of 34-km/sec at the time of Mars capture. [via DNA]

Liquid Engine 

The Liquid Engine (LM) on the MOM, also called the 440-Newton Liquid Engine, is a modified version of the Liquid Apogee Motor (LAM) used on earlier missions that required orbit raising, such as Chandrayaan.

The Liquid Motor is meant to raise the orbit of the MOM, propel it on a Trans-Mars trajectory, and slow it down for Mars orbit insertion.

The LM is capable of generating 440 Newton thrust. One of the mission challenges would be the restart of LM after a 300 day journey to Mars.

The MOM is also fitted with 8 22-Newton thrusters for controlling the orientation of the spacecraft and also for correcting the trajectory during the heliocentric phase of the mission.

The Liquid Engine and the thrusters us monomethyl hydrazine as fuel and nitrogen tetroxide as oxidizer. Pressurized helium gas is used to force the propellants into the combustion chamber.

The LM is fitted with two sets of propellant lines. After putting MOM on a heliocentric trajectory to Mars, the LM will remain idle for 300 days. Valves in LM's propellant lines might corrode and leak as a result of the lengthy coasting and trace presence of fuel in the lines, so ISRO has engineered a second set of propellant lines in the LM. A fresh set of propellant lines would be used for the 24-min Mars Orbit insertion burn on September 24, 2014. 





Mars Orbiter
The MOM with its solar panel, sensors and communication antenna deployed. Photo Courtesy ISRO

Payloads

ISRO initially planned to use the GSLV to launch a 500kg Mars orbiter, but scaled down its plans because of two back to back failures of the launcher in 2010.

The weight of the Mars orbiter was reduced to allow its launch using a PSLV-XL.

ISRO invited scientific payload proposals for the orbiter from agencies all over the world.

The following are the payloads short listed for the Mars orbiter: [via The Hindu]

  1. Thermal Infrared spectrometer weighing 4 kg to map the surface composition of Mars.
  2. Color camera weighing 1.4 kg
  3. Lyman-alpha photometer weighing 1.5 kg to measure atomic hydrogen in the Martian atmosphere.
  4. Mars Exospheric Neutral Composition Analyser (MENCA) to study the Martian atmosphere.
  5. Methane Sensor weighing 3.59 kg capable of scanning the entire Martian disc within six minutes.
The five scientific payloads are expected to be delivered to ISRO in March, 2013.

Past Mars orbiter missions launched by other nations have carried all the above payloads except the Methane Sensor.

Former Chairman of Indian Space Research Organisation Prof U.R. Rao told PTI on August 28, 2012 in Bengaluru, “We have selected very good experiments. One of the experiments is essentially to look for methane....where the methane comes from (what could be producing methane gas detected in the Martian atmosphere)."

"Some experiments have been selected and some are on the waiting list. The weight capability is not high. Total weight of the experiments selected can’t be more than 15 kg," he added. [via Hindu]

Methane Sensor

Observations over the last decade suggest that methane clouds form briefly over Mars during the summer months. 

Release of methane has been observed to occur from discrete surface locations on Mars, although the exact location and mechanism of release is still unknown. 

The presence of methane on Mars indicates the planet is still alive, in either a biologic or geologic sense, according to NASA and university scientists.

Dr. Michael Mumma of NASA's Goddard Space Flight Center in Greenbelt, Md. says: 

"Methane is quickly destroyed in the Martian atmosphere in a variety of ways, so our discovery of substantial plumes of methane in the northern hemisphere of Mars in 2003 indicates some ongoing process is releasing the gas.

"At northern mid-summer, methane is released at a rate comparable to that of the massive hydrocarbon seep at Coal Oil Point in Santa Barbara, Calif."

NASA scientists are hard at work modelling the methane cycle on Mars and the agency is keen to study in detail the methane cycle of the martian atmosphere using an orbiter, but ISRO might actually beat NASA to it if ISRO's Mars Orbiter is able to make the November 2013 launch window.

MOM Disassembled view.
MOM Disassembled view. Photo Courtesy ISRO.

Thermal Infrared Spectrometer

The Methane Sensor will work alongside the TIS to detect Methane, and if present, its source - bio-genic or geological?.

Mars Color Camera

The tri-colour MCC gives images and information about the surface features and composition of Martian surface. They are useful to monitor the dynamic events and weather of Mars. MCC will also be used for probing the two satellites of Mars - Phobos and Deimos.


Mars Exospheric Neutral Composition Analyser - MENCA


MENCA, weighing 4 kg, would provide the first ever insitu measurement of the neutral composition (in the mass range of 1 to 300 amu, with 1 amu resolution) and density distribution of the Martian exosphere (atmosphere ~ 500 km and beyond from the Martian surface).

The quadrapole mass spectrometer based MENCA payload is developed by SPL jointly with AVN and AERO Entities.

Lyman-alpha photometer (LAP)


LAP measures the relative abundance of deuterium and hydrogen from Lyman-alpha emission in the Martian upper atmosphere.
Measurement of D/H (Deuterium to Hydrogen abundance ratio) will improve our understanding of the process involved in the loss of water from the planet.

Mars Orbiter Power Supply

The Mars Orbiter will have a single solar array with three panels of 1400 x 1800 mm capable of generating 750 watts of power in Martian orbit.

It will also be equipped with a 36 AH Lithium-ion battery for power storage.

Mission Goals

On January 4, 2013,  Mr. Goswami, director of Physical Research Laboratory, Ahmedabad, while speaking to the press on the sidelines of the Indian Science Congress in Kolkata, said the mission would perform science that had so far not been done

"The mission has a very specific science objective as we want to study the atmosphere of Mars. This mission will explore things which have not been done previously by other countries,” he said.

An ISRO scientist told The Pioneer in August 2012 that the Indian orbiter "will concentrate on climate and geology which is going to be crucial for future explorations of Mars." [via The Pioneer]

The orbiter will join the international effort of assessing the suitability of Mars to life by searching for subsurface groundwater trapped in aquifers for thousands of years. It will also study the effect of solar wind on the Mars' atmosphere and its surface magnetic field.

Mission Challenges

Speaking to the press in September 2012, ISRO Chairman K Radhakrishnan said, "The voyage to Mars will take about 300 days. For the first time, we are doing a voyage for such a long time."

He added that the challenges faced by ISRO included developing on-board autonomy for the Mars Orbiter to handle and the infrastructure to maintain constant communication between the spacecraft and ground control. 

"This is one of the challenges…. Mars is important because we will be developing several critical technologies needed for the future," he said.

Other important challenges include
  1. Navigating the spacecraft from the Earth to Mars in deep space.
  2. Re-activating the temporary inactive sub-systems of the spacecraft once it reaches Mars after a 10-month journey through deep space.

Tracking

During launch, the MOM was tracked by ISRO ground stations at Sriharikota, Port Blair, Brunei and Biak in Indonesia till separation of stage 3. Following stage 4 ignition, the MOM was tracked by two specially equipped Shipping Corporation of India ships - 'Yamuna' and 'Nalanda' - positioned in the South Pacific Ocean. The ships relayed information on the last stage and ejection of the spacecraft into space, 

During its journey from Earth to Mars, MOM will be tracked by ISTRAC (ISRO Telemetry, Tracking and Command Network) using the Indian Deep Space Network (IDSN) at Baylalu on the outskirts of Bangalore and sea-borne S-band terminals.

IDSN comprises two large antennas, 18-m and 32-m in diameter

ISRO will also get position data from NASA’s Deep Space Network through its three stations located in Canberra, Madrid and Goldstone on the U.S. West Coast.

At the time of Mars capture in September 2014, tracking and communication with MOM will be done using the 70-metre antenna of Nasa's deep space network at Canberra in Australia.

Comet C/2013 A1

Discovered by Rob McNaught at the Siding Observatory in Australia on January 3, 2013, Comet C/2013 A1 is on a trajectory that will take it within close proximity of Mars, with a 1 in 8,000 probability that it will impact the planet at a of 2,00,000 kph. 

Following press reports that the comet could force a push back of the MOM, ISRO Chief K Radhakrishnan said on Wednesday, April 18, 2013, "The comet could bring some constituents, but we don't expect any effect on the spacecraft. It will pass 50,000 km away from Mars' surface. We will get more information on the comet in future and scientists are looking at all possibilities." 

According to JPL, the comet will flypast Mars at a distance of 138,000-km (86,000-mi) on October 19, 2014 and spacecraft at the planet might get a clear view of the comet's nucleus. It's also possible that dust from the comet, unofficially referred to as 2013 A1 Siding Spring, could damage spacecraft in orbit around the red planet.

NASA has plans to maneuver its orbiters to evade cometry debris. It's not known how much of a threat the MOM will face in its highly elliptical orbit and whether ISRO has plans to maneuver the spacecraft. MOM, which is expected to have an Apoapsis of 80,000 km could end up being in a uniquely advantageous position to study the comet, depending on the precise timing of the comet's flyby.  

ISRO Contemplates Comet Siding Spring Study

The comet will make its closest encounter with Mars around 1.40 a.m. IST on October 20 give or take 15 minutes [which will be 20.08 hours UTC on October 19]. 

The close encounter would provide MOM a rare opportunity to study the comet, but there exists a risk of collisions with cometry debris.

On October 6, 2014, ISRO lowered the apoapsis of the spacecraft from 78,000-km to 72,200-km, while keeping the periapsis at 423 km to minimize the risk.

The TOI reported on October 2, 2014 that a committee under former Isro chairman UR Rao met earlier in the week to work out the possibilities of MOM studying Comet Siding Spring.

"Now that MOM has completed one revolution around Mars, we know its position vis-a-vis the comet," Rao told TOI.

Scientists are calibrating the various payloads. Rao said the final decision on what type of study should be conducted will be taken in October. Studies have shown that the comet has a lot of methane and water and the once-in-a-lifetime opportunity to study the comet has got even Nasa excited.

Project Progress

On September 16, ISRO completed loading of time-tagged commands to execute Mars Orbit Insertion (MOI).

The PSLV-C25 took off at 2:38 PM on November 5, 2013 and 44-min later successfully placed MOM into an elliptical orbit with a period of 6-hr 50-min, perigee of 248.4-km, apogee of 23,550-km, inclination of 19.20-deg and AOP of 283-deg.  

The primary and secondary solar panels of the spacecraft were successfully deployed and all subsystems powered ON. Health of the Spacecraft is Confirmed Normal.

Stage 2 and 3 of the PLSV-C25 over performed during launch taking the MOM to a higher altitude than intended, but Stage-4 compensated accurately for the over-performance.

ISTRAC started receiving spacecraft telemetry from T+500 and took control of the spacecraft after it separated from stage-4. ISTRAC will now use the LAM of the spacecraft to extend it’s apogee to over a lakh km.

First Liquid Motor Orbit Raising Burn

The first orbit raising maneuver of India's Mars Orbiter Spacecraft was successfully performed starting at 01:17 AM IST  on November 07, 2013 when the LAM was fired for 416 seconds raising the spacecraft's apogee to 28825 km. The perigee is now 252 km.

Second Burn


The second orbit raising Maneuver was successfully performed starting at 02:18:51 AM IST on November 08, 2013, with a 570.6 s burn of the liquid motor, which raised the apogee from 28814 km to 40186 km.

Third Burnt

The third orbit raising maneuver was successfully performed using a liquid motor burn on Nov 09, 2013 for 707s  starting at 02:10:43 hrs IST, which raised the apogee to from 40,186 km to 71,636 km.

Fourth Burn

The fourth orbit raising operation conducted at 02:06 Hrs IST on November failed to raise the MOM's orbit to the planned 100,000 km. The incremental velocity imparted by the liquid motor was 35 m/s against the targeted 130 m/s. As a result, the apogee increased from 71,636-km to just 78,276-km.

ISRO plans a supplementary orbit raising operation at 05:00 hrs IST on November 12 to raise the apogee to around 100,000-km. ISRO has not announced if the additional burn would have consequences as a result of additional fuel burnt.

The following is the text of the ISRO statement on the fourth orbit raising burn

In the fourth orbit-raising operation conducted this morning (Nov 11, 2013), the apogee (farthest point to Earth) of Mars Orbiter Spacecraft was raised from 71,623 km to 78,276 km by imparting an incremental velocity of 35 metres/second (as against 130 metres/second originally planned to raise apogee to about 100,000 [1 lakh] km). The spacecraft is in normal health. A supplementary orbit-raising operation is planned tomorrow (November 12, 2013) at 0500 hrs IST to raise the apogee to nearly 1 lakh km.

During the orbit-raising operations conducted since November 7, 2013, ISRO has been testing and exercising the autonomy functions progressively, that are essential for Trans-Mars Injection (TMI) and Mars Orbit Insertion (MOI).

During the first three orbit-raising operations, the prime and redundant chains of gyros, accelerometers, 22 Newton attitude control thrusters, attitude and orbit control electronics as well as the associated logics for their fault detection isolation, and reconfiguration have been exercised successfully. The prime and redundant star sensors have been functioning satisfactorily. The primary coil of the solenoid flow control valve was used successfully for the first three orbit-raising operations.

During the fourth orbit-raising operations held today (November 11, 2013), the redundancies built-in for the propulsion system were exercised, namely, (a) energising the primary and redundant coils of the solenoid flow control valve of 440 Newton Liquid Engine and (b) logic for thrust augmentation by the attitude control thrusters, when needed. However, when both primary and redundant coils were energised together, as one of the planned modes, the flow to the Liquid Engine stopped. The thrust level augmentation logic, as expected, came in and the operation continued using the attitude control thrusters. This sequence resulted in reduction of the incremental velocity.

While this parallel mode of operating the two coils is not possible for subsequent operations, they could be operated independently in sequence.

Supplementary Burn

A supplementary 303.8 s orbit raising liquid engine burn starting at 23:45 PM on November 11, 2013 successfully raised the apogee from 78,276-km to to 1,186,42-km after. The spacecraft is now orbiting the earth once in 2802.34-min. Orbital inclination now is 19.28-deg and the angle of Perigee to 287-deg.

MOM after Supplementary Orbit Raising Maneuver
MOM after Supplementary Orbit Raising Maneuver. Photo Credit: ISRO

Fifth Burn

The fifth Orbit Raising Liquid Engine burn starting at 01:27 AM IST, November 16, 2013 and lasting 243.5 s raised the Apogee from 118642 km to 192874 km.

MOM after fifth Liquid Engine burn.
The spacecraft is now orbiting the earth once every 5475.24 at an inclination of 19.35-deg and a Angle of Perigee of 288-deg.

Trans-Mars Injection

1328.89-sec burn of ISRO's Mars Orbiter Mission (MOM) 440-N Liquid Engine at 00:49 AM on December 1, 2013 imparted the expected delta-v of 647.96 m/sec and achieved a successful Trans Mars Injection (TMI). The spacecraft reportedly used about 198 kg of fuel were used for firing the 440 Newton engine for 23 minutes.

(MOM's FB didn't mention that thrusters were also used for the TMI along with 440-N engine, as initially planned. ISRO had earlier announced that the 8 thrusters on the spacecraft would operate simultaneously with the 440-N engine. However, during 4th orbit raising, the 440-N engine had shut down prematurely when an attempt was made to operate it with the 8 thrusters. A report in The Hindu later said that the thrusters were used.)

MOM seems to have achieved Earth escape velocity with a 23-sec shorter burn of the 440-N engine than initially calculated?

Earlier ISRO had announced that at 00:36 hrs on December 1, the MOM's 440-Newton Liquid Engine and its 8 22-Newton thrusters will burn for 1,351-sec and impart the spacecraft a delta-v of 648 m/sec, sending it hurtling on a Mars intercept trajectory. 

Medium Gain Antenna Powered Up

Following Trans Mars Injection yesterday, December 1, 2013, the Medium Gain Antenna of the MOM was powered for long distance communication.

Medium Gain Antenna on the MOM
Medium Gain Antenna on the MOM

Heliocentric Phase of Journey to Mars

TMI will take MOM beyond the Earth's sphere of influence, which extends up to 9.25 lakh km, through a long helio-centric phase, to Mars' sphere of influence. 

MOM will escape from the sphere of influence (SOI) of the Earth around 1.15 a.m. of December 4, 2013.

On September 24, 2014, when the spacecraft intercepts Mars' orbit around the sun, it must be 376 km plus or minus 50 km above Mars. On the same day, the next crucial operation of the spacecraft’s Mars orbit insertion has to take place.

Mars mission Project Director S. Arunan told The Hindu on November 29, 2013, "The engine burn was aimed at giving the satellite a final escape velocity (which should be a minimum of 10.7 km per second). At launch, it got the speed of 9.8 km per second. The six orbit raises added 0.873 km per second; the December 1 burn should give it the last push of 0.648 km a second — which all add up to the crucial velocity of about 11.4 km per second."

The spacecraft will be travelling 680 million km on its Mars intercept trajectory.

Mid-Course Trajectory Corrections Maneuvers ( TCMs)

During mission planning, ISRO provisioned for upto four mid course tractory corrections - in December 2013, April 2014, August 2014 and early September 2014.

MOM's first planned mid-course trajectory correction maneuver (TCM) took place at 06:30 AM IST December 11, 2013 when the spacecraft's 8, 22 Newton Thrusters fired for 40.5s. MOM was then 2.9 million km from Earth. 

The second mid-course correction planned for April 2014 was deemed not necessary at that time. TCM-2 was eventually executed at 16:30 hrs on June 11, 2014 by firing 4, 22 Newton thrusters for 16 seconds from 4.30 p.m imparting an incremental velocity of 1.574 m/sec to the spacecraft.

Ground controllers at ISRO Telemetry, Tracking and Command Network (ISTRAC) Station, Bangalore uploaded TCM commands to the orbiter which then executed the maneuver autonomously at the precise time. 

M. Annadurai, Program Director Indian Remote-sensing Satellites and Small Satellites Systems, ISRO, told The Hindu, "Everything went perfectly well.” 

He added "We are happy because this is, in a way, a simulation for the crucial Mars Orbit Injection (MOI)” that would take place on September 24.

"The MOI will be exactly similar to this except that we fired four small Newton thrusters today. But we will fire the 440-Newton liquid engine  of the spacecraft for the MOI,” he said.

A final mid-course correction is scheduled on September 14, 2014, 10 days before insertion it into the Martian orbit.  [via The Hindu]

MOM in Good Health 100 Days into Journey to Mars

ISRO reported on February 11, 2014 that the MOM is in good health 100 days, 190 million km into its nearly 300-day, 680-km journey to Mars.

"Three more TCM operations are planned around April 2014, August 2014 and September 2014. 

The propulsion system of the spacecraft is configured for TCMs and the Mars Orbit Insertion (MOI) Operation. On February 6, 2014, all the five payloads on Mars Orbiter spacecraft were switched 'ON' to check their health. 

The health parameters of all the payloads are normal. Presently, the spacecraft is at a radio distance of 16 million km causing a one way communication delay of approximately 55 seconds. After travelling the remaining distance of about 490 million km over the next 210 days, the spacecraft would be inserted into the Martian Orbit on September 24, 2014."

MOM in Good Health on March 1, 2014

MOM project director S Arunan said on March 1, 2014 that the spacecraft was functioning normally.

“The second of the four trajectory correction maneuver will be made, probably on April 9, to make minor changes that may be required owing to the solar radiation pressure on the spacecraft,” he told journalists here on Saturday, on the sidelines of Probe-2014, a symposium at the National Institute of Technology, Tiruchi (NITT). 

MOM Past Halfway Mark in Journey to Mars


On April 09, 2014 at 9:50 am IST, MOM crossed the half-way mark of its journey to the Red Planet along the designated helio-centric trajectory. 

ISRO has been continuously monitoring the Spacecraft using its Deep Space Network complemented by that of NASA-JPL. As the Spacecraft is on its designated trajectory, the TCM planned for April 2014 is not considered essential. If required, the next TCM is planned to be carried out in June 2014. 

Mars Orbiter Spacecraft and its five scientific instruments are in good health. Periodic tests are being done on the different levels of autonomy built into the Spacecraft for managing contingencies. 

Status on April 4, 2014

As on April 4, 2014 MOM had traveled 35-million km on its journey to Mars.

MOM in Good Health on May 12, 2014

ISRO Chairman K Radhakrishnan told PTI on May 12, 2014, " "Mars mission is going well and will reach the orbit on September 24, 2014."

He added that it was now taking four minutes for a signal from the ground station to reach the spacecraft.

SRO's Mars Orbiter Mission spacecraft is now at a distance of about 117 million km, traveling with a velocity of 23 km/s.The present distance between MOM and Mars is 24 million km. The communication signals sent from MOM takes 6 minutes and 30 seconds to reach the Ground Stations. Another 92 days to go for Mars Orbit Insertion.

TCM 2

A second second trajectory correction maneuver (TCM-2) on June 11, 2014 successfully corrected the drift in trajectory because of solar winds and put the spacecraft back on a Mars intercept course. Following TCM-2, S. Arunan, Project Director, Mars Orbiter Mission, told the press, “All the health parameters of the Mars Orbiter are all right. Its payloads have been operated and checked. They are doing well. All the systems and sub-systems are doing well.”

As on June 12, 2014 the radio distance between MOM and the Earth was 102 million km. A radio signal from the Earth to the Spacecraft would take about 340 seconds. The spacecraft had traveled a distance of 466 million km as part of its total Journey of 680 million km. 

Status on June 24, 2014

In a post on the MOM FB Page on June 24, 2014 ISRO  announced that spacecraft is now at a distance of about 117 million km, traveling with a velocity of 23 km/s.The present distance between MOM and Mars is 24 million km. The communication signals sent from MOM takes 6 minutes and 30 seconds to reach the Ground Stations. Another 92 days to go for Mars Orbit Insertion.

Status on July 12, 2014

On July 12, 2014 ISRO announced on Twitter and FB that MOM has traveled 525 million km in a helicentric arc enroute to a rendezvous with Mars. Radio signals now take 15-min to travel from Earth to MOM and back. MOM's Mars orbit insertion is planned exactly 75 days from today.

August TCM Cancelled

On August 1, 2014, ISRO announced that a trajectory correction scheduled for August will not be required because of the accuracy with which MOM is tracking its planned trajectory. The third and final trajectory correction will now take place on September 14, 2014, 10 days before insertion it into the Martian orbit.

Medium Gain Antenna Characterization Completed on August 7, 2014

On August 7, 2014 ISRO announced that MOM had successfully completed characterization of its Medium Gain Antenna, which would be used for communicating with Earth during the critical Mars Orbit insertion (MOI). Only 14% of the journey remains in MOM's heliocentric arc towards MOI.

Restarting Liquid Engine

During the launch of a Geo-synchronous Satellite the Liquid Motor is restarted a week after its launch. In the case of Chandrayaan-1 in 2008, it was restarted after a fortnight; ISRO had qualified it for restart after one month.

In the case of MOM, the LM would need be restarted after about 300 days. To guard against a failure, ISRO has provided a set of parallel circuits for the propellants’ flow-lines and also provided redundancy in the form of a latch-valve. 

Following its December 1 Trans-Mars injection burn, one portion of the fluid circuit was closed. The parallel path will be energized for a 5-sec test burn of the LM at 2:30 pm on September 22.

The trajectory error induced by the test burn will be corrected subsequently using MOM's eight 22N thrusters. If the LAM fails to fire, ISRO will attempt a Mars orbit insertion using the eight 22N thrusters.

 If all goes well, the parallel path would be used for the  the 24-min Mars Orbit insertion burn on September 24, 2014. 

ISRO tested the Liquid Engine in a special test facility established at the Liquid Propulsion Systems Center at Mahendragiri, Tamil Nadu. On restart, the engine performed within specifications, with just a two percent degradation in performance. 

MOI Commands Uploaded

On September 16, ISRO completed loading of time-tagged commands to execute Mars Orbit Insertion (MOI).

TCM / LM Test Firing Commands Upload

On September 17, 2014, uploading of commands for Fourth Trajectory Correction Maneuver (TCM) and test-firing of Main Liquid Engine (scheduled for Sep 22, 2014) is in progress.

Liquid Motor (LM) Test Burn /  Final TCM Successful

The LM was successfully fired for a duration of 3.968 seconds at 1430 hrs IST on September 22, 2014. The test / trajectory correction burn changed the spacecraft's velocity by 2.18 m/sec. 

MOI Successful

Mars Orbiter Insertion (MOI) burn of the LM and eight thrusters started at 07:17:32 hrs IST on September 24, 201 and lasted for 1388.67 seconds, reducing the velocity of the spacecraft by 1099 metre/sec putting MOM in an elliptical orbit around Mars.
Telemetric confirmation received by ISRO around 8.15 a.m. confirmed that the 24-min burn had successfully reduced the spacecraft's velocity from 5.7 km/sec to 4.6 km/sec.

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. 

The sequence of events leading to MOI was as follows
  1. Change Over to Medium Gain Antenna with wider field of view
  2. Forward rotation starts. The spacecraft is required to align the direction of firing for effective braking. 
  3. Eclipse starts - The Spacecraft is in shadow of Mars. Spacecraft operates on battery.
  4. Burn Start of Main Liquid Engine Confirmed
  5. Occultation starts - presence of Mars between MOM and Earth line of sight snaps radio link.
  6. Eclipse ends
  7. Main Liquid Engine Burn Ends
  8. Backward rotation starts
  9. Occultation ends
  10. Spacecraft telemetry confirms successful MOI

7.59: Occultation over. Telemetry confirms successful MOI
7.48: Main Liquid Engine burn completion
7.46: Occultation start. The spacecraft is now out of range of radio signals. 
7.38: In about half hour, ISRO is expected to get the first confirmation from NASA's ground station in Canberra, Australia.
7.31: Burn start confirmed from telemetry.
7.17: Burn start.
7.16: Eclipse start
6.56: Forward rotation start. 

Mars Orbit Parameters

Immediately following MOI, the assessed periapsis was 427 km and the apoapsis was 78,500 km. The final values will be obtained after several hours.

The spacecraft takes 3.2 earth days to orbit Mars.

Payload Activation

The Mars Color Camera was the first payload to be activated following MOI. By October 1, 2014, all payloads were activated.

Fuel Status

The MOM carried 850-kg of fuel at launch, of which 365-kg was used for orbit raising and 198-kg for TMI. That left  a healthy balance of 287-kg.

DNA reported on December 19, 2013, quoting ISRO's AS Kirankumar, that the fuel burnt till date is 470 kg.

Following TCM-2 on June 11, the spacecraft has 290 kg of fuel left. About 240 kilograms will be burnt as the spacecraft enters the Martian orbit on September 24, 2014. [via Indian Express]


MOM Autonomy Features


The following MOM features give it the ability to operate autonomously.

  1. The MOM has a Fault Detection, Isolation and Reconfiguration (FDIR) using which it automatically switches to a backup system / mode.
  2. The spacecraft has an onboard sequence that can be loaded with a sequence of commands. The MOM then automatically executes the command sequence at a programmed time.
  3. The spacecraft can put itself in the Safe mode whereby it conserves power, points it communication antenna towards the Earth and waits for commands from control station.

MOM After Launch Testing

During MOM's six orbit raising Liquid Engine burns from November 7 to November 16, ISRO tested the redundancies built into the system.

The gyroscopes, accelerometers, star-sensors, and attitude and orbit-control electronics, attitude control thrusters, the FDIR and the thrust augmentation logic, which enables the augmentation of the thrust of the 440 Newton liquid engine by eight numbers of 22 Newton control thrusters during the critical phases of operation, were tested. The termination of the burn of the 440 Newton engine, based on the feedback from the accelerometer, was tested. The on-board sequencer, which is used to store and initiate time-tagged command, was also tested.

ISRO is currently in the process of testing the orbiter’s high-gain antenna and the medium-gain antenna which are required for long distance communication. It will also energize its scientific instruments to check their health.


MOM Martian Orbit Details


Pre-Launch Activity


A national committee of scientists chaired by former Isro chief U R Rao gave the MOM a go-ahead on Friday, September 20, 2013. A pre-shipment review will be held on September 26 and the spacecraft moved to Sriharikota on September 30 for integration with the launcher. Launch is scheduled for October 28 from Sriharikota between 3.30pm and 4pm.
ISRO unveiled the MOM to the media for the first time on Wednesday, September 11, 2013 and announced that launch will occur between October 21 and November 19 from Sriharikota. The orbiter is set to be moved to Sriharikota on September 27

On July 2, 2013, speaking to the press after the successful launch of IRNSS-1A onboard PSLV-C22XL, ISRO Chief K Radhakrishnan said, "We are planning to start stacking the Mars mission from July 29. We are looking to launch the mission any day from October 21. Either on November 28 or 29, the Mars mission is scheduled to leave the Earth’s orbit and start its voyage to Mars.” 

On April 18, 2013   ISRO Chief K Radhakrishnan said"India's Mars Orbiter is on schedule. The five instruments are ready and will be integrated soon.

He added, "The spacecraft sub systems are in the process of integration while the launch vehicle, PSLV, is also getting ready. It will be integrated from August onwards."

On March 29, 2013 the Deccan Herald reported that ISRO had started integration of the Mars orbiter.

Sources within the ISRO told the newspaper that preliminary design reviews had been completed and the integration process has begun. 

"The structure has been delivered to clean room and the propulsion system integration is in the final stage," a source said.

ISRO is planning to move the newly developed rocket engine for orbital insertion to Sriharikota by April end after the completion of the high vacuum testing here.

On March 17, 2013, while addressing mediapersons, ISRO Chief K Radhakrishnan said: "The Mars mission is progressing well and the payloads will be received by March end for integration."

"We require the PSLV C25 for the launch. Sub-systems are currently being tested at the satellite center here. By September, we shall have the satellite ready. Also ground station augmentations are being made," Radhakrishnan added.

As on January 4, 2013, a proto flight model had been completed, ahead of the flight model to be developed by March end 2013.

The Liquid Apogee Motor (LAM) that will propel the Mars orbiter out of Earth orbit and send it hurtling towards Mars was tested for 670 seconds on Monday, October 8, 2012 at ISRO's Liquid Propulsion Systems Center at Mahendra Giri in Tamil Nadu.

"The test was successful and will go on for about 45 days," ISRO chief spokesperson Devi Prasad Karnik told the TOI.

The rocket engine for orbital insertion around Mars was due to be tested in June 2012, P C Agarwal, a space scientist who was part of the ISRO-appointed committee that evaluated the feasibility of the mission, told the press in March 2012. 

Mars Orbiter Team


In October 2012, ISRO announced Dr M Annadurai as program director of the Mars Orbiter Mission. SK Shivkumar will oversee design and development of the Orbiter. [via DNA]

Annadurai was earlier project director of Chandrayaan 1. Shivkumar, who played a key role in realizing the ground segment for  Chandrayaan 1, is the director of  Isro Satellite Center in Bengaluru, which will be t he lead center for the design, development, fabrication and testing of the Mars Orbiter Mission's payloads and satellites.

Following his appointment, Annadurai told DNA, “It is one more challenge for us to execute. The Mars Orbiter Mission is an extension of the earlier mission (Chandrayaan I) as we are looking to explore beyond the Moon.” 

S. Arunan is the Mars mission Project Director.
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