In a historic event, India has become only the fourth discrete nation or group of nations—after the United States, Russia, and the European Space Agency (ESA)—to successfully despatch a homegrown spacecraft en-route to the Red Planet. Its Mars Orbiter Mission (MOM), also known as “Mangalyaan” (Hindi for “Mars Craft”), completed its critical Trans-Mars Injection (TMI) maneuver early Sunday, 1 December, India Standard Time (IST), burning its 440-Newton-thrust Liquid Apogee Motor (LAM) for 1,328.89 seconds—more than 22 minutes—to increase the spacecraft’s velocity by 2,125.85 feet per second (647.96 meters per second) to depart Earth’s gravitational influence and begin its 10-month journey.
According to the Indian Space Research Organisation (ISRO), the long-awaited event began at 12:30 a.m. IST Sunday, 1 December, with a “Forward rotation of spacecraft to put it into the right orientation to perform Trans-Mars Injection (TMI) operation.” Nineteen minutes later, at 12:49 a.m. IST, the 22-minute-plus LAM burn got underway, monitored by the Spacecraft Control Centre at ISRO Telemetry, Tracking and Command Network (ISTRAC) in Peenya, Bangalore, with support from the Indian Deep Space Network (IDSN) installation at Byalalu.
Lofted atop India’s Polar Satellite Launch Vehicle (PSLV) from the Satish Dhawan Space Centre on the barrier island of Sriharikota back on 5 November, the relatively limited propulsive yield of both the rocket and the spacecraft’s engine made it infeasible to inject it directly onto a trans-Mars trajectory. Instead, MOM/Mangalyaan was inserted very precisely into a highly-elliptical Earth orbit of about 155 x 14,600 miles (250 x 23,500 km) by the PSLV. The spacecraft was then tasked with executing a series of six LAM burns over a period of several weeks to steadily increase its apogee to a maximum of 119,846 miles (192,874 km) from the Home Planet, whereupon it would escape Earth’s sphere of gravitational influence and establish itself onto a hyperbolic trajectory to reach Mars on 24 September 2014.
The 2,980-pound (1,350-kg) MOM/Mangalyaan spacecraft is equipped with five discrete scientific instruments—the Methane Sensor for Mars (MSM), Mars Colour Camera (MCC), Mars Exospheric Neutral Composition Analyser (MENCA), Thermal Infrared Spectrometer (TIR), and Lyman-Alpha Photometer (LAP)—and will demonstrate the technology needed to deliver a spacecraft to the Red Planet and conduct meaningful science. Upon arrival in September 2014, it will spend at least six months orbiting Mars, focusing on the morphology, topography, and mineralogy of the surface, together with the dynamics of its thin upper atmosphere, its loss of water, the influence of solar wind and radiation, and the nature of its moons, Phobos and Deimos.
Following its launch at 2:38 p.m. IST on Tuesday, 5 November, MOM/Mangalyaan was placed into an orbit which very closely paralleled pre-flight projections, inclined 19.27 degrees to the equator and with an orbital period of slightly less than seven hours. After separation from the final stage of the PSLV, the spacecraft’s main antenna and solar arrays were successfully deployed, and the first orbit-raising burn of the LAM began at 1:17 a.m. IST on Thursday, 7 November. Under the command of ISTRAC, the engine was ignited for 416 seconds and lifted MOM/Mangalyaan’s apogee to 17,550 miles (28,852 km).
This first burn was followed, at 2:18 a.m. IST Friday, 8 November, by a 570-second firing to push the apogee further to 24,970 miles (40,186 km). The LAM ignited for the third time at 2:10 a.m. IST Saturday, 9 November, increasing the spacecraft’s high point to 44,500 miles (71,636 km). According to ISRO, many parameters of MOM/Mangalyaan’s systems and redundancy features were evaluated during this period. “During the first three orbit-raising operations,” it was explained, “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 added that prime and backup star sensors and associated instrumentation continued to function normally.
With the fourth burn on Monday, 11 November, ISRO expected MOM/Mangalyaan to expand its apogee even further to beyond 62,100 miles (100,000 km) from Earth. This burn should have imparted an incremental velocity of around 426 feet per second (130 meters per second), but actually added just 114 feet per second (35 meters per second), raising the apogee to just 48,640 miles (78,276 km). “During the fourth orbit-raising operations,” ISRO explained, “the redundancies built-in for the propulsion system were exercised.” This work included energizing the primary and redundant coils of the solenoid flow control valve of the LAM and logic for thrust augmentation by the attitude-control thrusters. “However,” ISRO continued, “when both primary and redundant coils were energized together, as one of the planning 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.” ISRO noted that, in spite of the thrust shortfall, MOM/Mangalyaan remained healthy and “a supplementary orbit-raising operation” was planned for Tuesday, 12 November. This supplementary burn started at 5:03 a.m. IST and lasted 303.8 seconds, with the orbital apogee successfully raised to 73,720 miles (118,642 km).
Two further LAM firings positioned the spacecraft for its departure from Earth’s sphere of gravitational influence. On Saturday, 16 November, a 243.5-second burn got underway at 1:27 a.m. IST and produced an observed change in apogee to 119,846 miles (192,874 km). The final burn then occurred yesterday to impart a final impetus to establish MOM/Mangalyaan onto its hyperbolic trajectory to intercept Mars. “The spacecraft leaves Earth in a direction tangential to Earth’s orbit,” explained ISRO’s official brochure for the mission, “and encounters Mars tangentially to its orbit,” noting that these “minimum-energy” opportunities to reach the Red Planet under conditions of the best economy of propellant expenditure, mission duration, and trajectory design arise approximately every 780 days. In addition to the LAM burns, several health checks of the spacecraft and payloads have been performed, with ISRO confirming that all systems continue to operate normally.
“The spacecraft arrives at the Mars Sphere of Influence in a hyperbolic trajectory,” continued ISRO. “At the time the spacecraft reaches the Closest Approach to Mars (periapsis), it is captured into planned orbit around Mars by impacting delta-V retro, which is called the Mars Orbit Insertion (MOI) manoeuvre.” According to current mission plans, MOI will occur at 2:34 a.m. IST on 24 September 2014, and MOM/Mangalyaan will enter an orbit of 310 x 50,000 miles (500 x 80,000 km), inclined 150 degrees. In this highly elliptical orbit, it will circle the planet once every 76.72 hours. Quoting ISRO officials, FirstPost India noted that the minimum life of MOM/Mangalyaan in Mars orbit is six months, but hopes are high that it will exceed this target.
This mission is both highly ambitious and highly unlikely for the world’s second most populous nation, and its merits and motivations have triggered considerable debate. It is described as “a technology demonstration project,” and its primary task is to prove that India can design, plan, manage, launch, and operate a deep-space mission across the enormous gulf to reach the Red Planet. It only received formal approval and a $41 million financial injection from the Indian government in August 2012. With anticipated costs as high as $100 million, the mission has unsurprisingly provoked debate from critics who feel that India could better spend the money on more down-to-earth issues, such as power failures, droughts, and the aftermath of Cyclone Phailin. Still, one government official retorted in a BBC interview that “India is today too big to be just living on the fringes of high technology.”
Hopes are high for MOM/Mangalyaan, as India sets out on a path to become the fourth discrete organization, nation, or group of nations to successfully send its own mission to Mars. Only Russia, the United States, and the member states of the European Space Agency (ESA) have accomplished this feat to date. Yet the stakes are even higher, particularly in the wake of the ignominious fate of Russia’s Fobos-Grunt and China’s Yinghuo-1 spacecraft, which failed to leave Earth orbit in November 2011 and burned up in the atmosphere a few weeks later. “For Mars, there were 51 missions so far the world around,” ISRO Chairman Dr. K. Radhakrishnan told India’s Economic Times last week, “and there were 21 successful missions. It’s a complex mission.” He pointed out that the difference between success and failure in any space enterprise “is very, very thin,” but stressed that even a failure provides a stepping stone to success. Coming less than two years after the Fobos-Grunt and Yinghuo-1 failure, Dr. Radhakrishnan denied overt competition with China and scoffed at the notion of a “race” to Mars between the two nations. “We are in competition with ourselves,” he said, “in the areas that we have charted for ourselves. Each country has its own priorities.”
Dr. Radhakrishnan has admitted that the MOM/Mangalyaan mission will be a challenge, an opportunity, and a matter of national pride, and certainly illustrates the growing maturity of India’s space program. “Such scientific missions post very tough challenges to technologists,” he said. “Some of the outcomes—for example, the in-built autonomy we are providing in this spacecraft—can become a reality as a product or system and be used in satellites to improve their efficiency. So they percolate to application, which is our main objective. It could be something like forecasting cyclones. There is always relevance for a mission such as this.”
The spacecraft’s in-built autonomy has been incorporated in response to a recognition that the maximum Earth-Mars Round Trip Light Time (RLT) will be 42 minutes, making it “impractical to micromanage the mission from Earth with ground intervention.” As a consequence, MOM/Mangalyaan adopts autonomous Fault Detection, Isolation, and Reconfiguration (FDIR) logic, none of whose actions will disrupt the spacecraft’s Earth Pointing Attitude. ISRO considers this system to be essential during any communications problems or interruptions—during eclipses, for example—and it will safeguard the spacecraft during its insertion into Martian orbit.
Conditions in interplanetary space and in orbit around the Red Planet have also been simulated during numerous ground tests. The performance characteristics of the critical Liquid Apogee Motor have been evaluated in ISRO’s High Altitude Test Facility, whilst thermal balance tests have yielded baseline data for Mars radiation flux and have helped to validate thermal models. In order to handle the frigid cold of a Martian eclipse, MOM/Mangalyaan solar array “coupons” have been subjected to temperature conditions as low as -200 degrees Celsius, qualifying both the cells and their bonding agents. The spacecraft’s communications system has been exhaustively tested and verified by both ISRO and NASA’s Jet Propulsion Laboratory (JPL) of Pasadena, Calif., whose Deep Space Network (DSN) will work alongside the Indian Deep Space Network (IDSN) in tracking MOM/Mangalyaan. These tests have demonstrated “communications management” at the predicted distance between Earth and Mars at the point of MOI, an estimated 133 million miles (214 million km), and after six months in orbit, an estimated 233 million miles (375 million km).
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