Fwd: India's Mars Orbiter Mission (MOM) Requires Extra Thruster Firing after Premature Engine Shutdown

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From: "Gary Johnson" <gjohnson144@comcast.net>
Date: November 12, 2013 4:49:51 PM CST
To: "Gary Johnson" <gjohnson144@comcast.net>
Subject: FW: India's Mars Orbiter Mission (MOM) Requires Extra Thruster Firing after Premature Engine Shutdown

 

 

 

 

November 11, 2013
Supplementary Orbit Raising Manoeuvre Planned for Mars Orbiter Spacecraft 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.

 

Copyright 2008 ISRO, All Rights Reserved.

 

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India's Mars Orbiter Mission (MOM) Requires Extra Thruster Firing after Premature Engine Shutdown

by Ken Kremer on November 11, 2013

Spectacular view of the PSLV C25 rocket leaving the First launch pad with ISRO's Mars Orbiter Mission spacecraft on Nov. 5, 2013. Credit: ISRO

India's Mars Orbiter Mission (MOM) probe suffered a surprise hiccup overnight (Nov. 11 IST) when the main engine shut down prematurely and left the country's first ever mission to the Red Planet flying in a significantly lower than planned interim elliptical orbit around Earth – following what was to be her 4th orbit raising burn since last week's flawless launch.

"MOM is in normal health," at this time according to the Indian Space Research Organization (ISRO) - which has now scheduled a supplementary main engine firing for early Tuesday (Nov. 12) to boost the crafts orbit the missing 20,000 km required.

Monday's engine firing only raised MOM's apogee (farthest point to Earth) from 71,623 km to 78,276 km compared to the originally planned apogee of about 100,000 [1 lakh] km), said ISRO in a press release.

This is the first serious problem to strike MOM in space. And it seemed clear to me something might be amiss when ISRO failed to quickly announce a successful completion of the 4th firing as had been the pattern for the initial three burns.

Trajectory graphic showing new supplemental 5th Midnight Maneuver thruster firing of ISRO's Mars Orbiter Mission Spacecraft planned for Nov. 12 (IST) following the premature main engine shutdown during 4th orbit raising engine burn on Nov. 11. Credit: ISRO

The premature shutdown of the liquid fueled 440 Newton main engine "imparted an incremental velocity of 35 metres/second as against 130 metres/second originally planned," ISRO stated.

That's barely a quarter of what was hoped for.

"A supplementary orbit-raising operation is planned tomorrow (November 12, 2013) at 0500 hrs IST to raise the apogee to nearly 1 lakh [100,000] km."

A series of six absolutely essential firings of the 440 Newton main engine – dubbed "midnight maneuvers" – had been originally scheduled by Indian space engineers.

The purpose of the "midnight maneuvers" is to achieve Earth escape velocity by gradually raising MOM's apogee over several weeks, and set her on a trans Mars trajectory to the Red Planet, following the spectacular blastoff on Nov. 5 from India's spaceport.

Graphic showing trajectory that had been planned for the Fourth Midnight Maneuver of ISRO's Mars Orbiter Mission Spacecraft on Nov. 11 until early shutdown of the 440N liquid fueled main engine. Credit: ISRO

MOM was due to depart Earth's orbit on Dec. 1 after accomplishing the 6th of the originally scheduled thruster firings – and begin a 10 month long interplanetary cruise to Mars.

MOM's picture perfect Nov. 5 liftoff atop India's highly reliable four stage Polar Satellite Launch Vehicle (PSLV) C25 from the ISRO's Satish Dhawan Space Centre SHAR, Sriharikota, precisely injected the spacecraft into an initial elliptical Earth parking orbit of 247 x 23556 kilometers with an inclination of 19.2 degrees.

The 1st, 2nd and 3rd thruster firings were spot on and incrementally raised MOM's apogee from 23556 km to 28814 km, 40186 km and 71,623 km respectively.

The next firing had been slated for Nov. 16.

Here's how ISRO described the source of the main engine shutdown:

"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."

Artists concept shows Midnight Maneuver thruster firing of the liquid engine of ISRO's Mars Orbiter Mission Spacecraft. Credit: ISRO

It is not known at this time how or whether the requirement for a supplemental "midnight maneuver" engine firing will affect the mission's timing at Earth and its operations and longevity at Mars.

Why are the firings called midnight maneuvers?

"Firing has to happen near the perigee and in the visibility from ISTRAC ground stations. All these orbits have argument of perigee of ~285 deg. When all these constraints are put together, firings time will almost always fall in to midnights of Indian sub continent," said ISRO in response to a readers inquiry.

In the latest update, ISRO reports: "After achieving an apogee of around 78,000 km in last night's Maneuver, ISRO's Mars Orbiter Mission Spacecraft is all set to reach the apogee of One lakh km in a supplementary maneuver scheduled for 5 AM tomorrow. [Nov 12]."

MOM was to arrive in the vicinity of Mars on September 24, 2014 when the absolutely essential Mars orbital insertion firing by the 440 Newton liquid fueled main engine will slow the probe and place it into a 366 km x 80,000 km elliptical orbit.

Clouds on the ground ! The sky seems inverted for a moment ! Blastoff of India's Mars Orbiter Mission (MOM) on Nov. 5, 2013 from the Indian Space Research Organization's (ISRO) Satish Dhawan Space Centre SHAR, Sriharikota. Credit: ISRO

If all goes well, India will join an elite club of only four who have launched probes that successfully investigated the Red Planet from orbit or the surface – following the Soviet Union, the United States and the European Space Agency (ESA).

The low cost $69 Million MOM mission is the first of two new Mars orbiter science probes from Earth blasting off for the Red Planet this November.

Half a world away, NASA's $671 Million MAVEN orbiter remains on target to launch in less than one week on Nov. 18 – from Cape Canaveral, Florida.

Both MAVEN and MOM's goal is to study the Martian atmosphere, unlock the mysteries of its current atmosphere and determine how, why and when the atmosphere and liquid water was lost – and how this transformed Mars climate into its cold, desiccated state of today.

The MAVEN and MOM science teams will "work together" to unlock the secrets of Mars atmosphere and climate history, MAVEN's top scientist Prof. Bruce Jakosky told Universe Today.

 

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Indian Mars mission weathers first snag
BY STEPHEN CLARK
SPACEFLIGHT NOW
November 11, 2013

A week into its mission, India's Mars probe overcame a bout of engine trouble Monday with an unplanned maneuver to boost its orbit after a rocket firing failed to do its job Sunday.

Artist's concept of the Indian Mars orbiter. Credit: ISRO
 
India launched the probe on a roundabout trajectory to Mars because the 1.5-ton spacecraft was too heavy for its rocket to place it on a direct course to the red planet.

The tradeoff means the spacecraft is still in Earth orbit, and it must use its own propulsion system to gain speed and break free of Earth's gravity.

Engineers planned six maneuvers to gradually nudge the probe higher around Earth, with a final engine burn planned Nov. 30 to escape Earth's gravitational influence.

The spacecraft accomplished three rocket firings last week, but the fourth burn Sunday was aborted before it could raise the probe's altitude to the maneuver's target of 100,000 kilometers, or approximately 62,000 miles.

Officials said the spacecraft instead reached an orbit with an apogee, or high point, of 78,722 kilometers, or 48,915 miles.

Controllers devised a supplemental burn Monday to make up for the shortfall and boost the probe up to a 72,720-mile apogee, and the five-minute thruster firing was completed as expected, according to a post on the mission's official Facebook page.

The probe's liquid-fueled main engine prematurely stopped its burn Sunday when propellant abruptly stopped flowing to the thruster. The problem occurred when primary and redundant coils of the engine's solenoid flow control valve were "energized" together, the Indian Space Research Organization said in a statement.

"The thrust level augmentation logic, as expected, came in and the operation continued using the attitude control thrusters," ISRO said in a statement. "This sequence resulted in reduction of the incremental velocity."

Diagram of Mars probe's orbit-raising maneuvers since launch. The current orbit is colored blue in this image. Credit: ISRO
 
The craft's main engine is designed to produce about 440 Newtons of force, equal to about 98 pounds of thrust. The attitude control thrusters, which help point the spacecraft and are used for smaller maneuvers, generate much less thrust.

Ground controllers were testing the engine's built-in redundancies, including the redundant coil, during Sunday's engine firing, and "while this parallel mode of operating the two coils is not possible for subsequent operations, they could be operated independently in sequence," ISRO said.

Engineers wanted to test the ability of the coils to operate simultaneously to avoid the possibility of a failure of one of the coils causing a problem during future critical burns, such as the lengthy make-or-break engine firing required to place the probe into orbit around Mars.

The first three orbit-raising burns were all conducted without incident, according to ISRO.

"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," ISRO said. "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."

The next burn is scheduled for Nov. 15, according to ISRO.

The Mars Orbiter Mission, with a price tag of 4.5 billion Indian rupees or $71 million, is India's first Mars project. It launched Nov. 5 atop a Polar Satellite Launch Vehicle is scheduled to arrive in orbit at the red planet Sept. 24, 2014.

The probe carries instruments to return color images of the Martian surface, study the planet's composition and survey the atmosphere for methane, a potential indicator of life.  

 

© 2013 Spaceflight Now Inc.

 

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