Nearly 20 years after the U.S. probes Viking 1 and Viking 2 successfully landed on Mars in 1976, America’s next successful mission to our neighbouring red planet began. The Mars Global Surveyor (MGS) spacecraft was launched in 1996 with the objective of orbiting Mars and collecting images using a number of instruments.
The MGS had been born out of a failure. When we looked at the Mars Observer, launched in 1992, in this column last month, we threw light on how NASA lost contact with it just days before its planned orbit insertion. While the failure definitely hurt, the fact that out-of-control costs nearly quadrupled the project price for Mars Observer stung them even further.
“Faster, better, cheaper”
When it was time for MGS, NASA set about building a “faster, better, cheaper” set of spacecraft. The programme had successes and failures as they went about using smaller teams and less complicated components to construct low-cost spacecraft. The MGS was definitely a success.
Launched from the Kennedy Space Center aboard a Delta II rocket on November 7, 1996, MGS went into Earth orbit before firing its engines once more to accelerate towards Mars. A little over 10 months later, on September 11, 1997 (September 12, UTC), MGS successfully achieved orbit insertion around Mars.
Aerobraking technique
A pioneer in many ways, MGS utilised a new aerobraking technique to finalise its orbit around Mars. By pushing against the Martian atmosphere gradually through its first months at the red planet, MGS successfully put itself in its final orbit. While the method was devised to save on the cost of sending more fuel on board, the technique proved extremely successful and hence was put to use again by the Mars Reconnaissance Orbiter and Mars Odyssey missions.
“Face of Mars” as pictured by the Mars Global Surveyor.
One of the first targets for MGS was the “Face of Mars.” Snapped by Viking 1 in 1976, the picture looked like a human face gazing up at the sky, leading to many conspiracy theories. Even though NASA was already aware that the “face” was a trick of the shadows, MGS was made to pass over the same location as Viking 1 in April 1998. The high-resolution images that MGS came up with were enough to debunk many a conspiracy theory.
Wind plays its part
In the years that followed, MGS provided plenty of snapshots that showed a possible ancient river channel, extremely slow dunes, drifts and sand sheets on the Martian surface. Many of these features indicated that wind was a huge factor in shaping the history of Mars.
Mars as pictured by Mars Global Surveyor. | Photo Credit: NASA
The MGS used a laser altimeter to map the Martian terrain; employed a magnetometer to detect traces of magnetic field; and mapped over 20 new impact craters during its operational time. Peering from its vantage point in orbit, MGS was even able to spot hematite, a mineral that forms in water.
Unexpected end
By the time MGS unexpectedly fell silent in November 2006, it had outlasted its design lifetime by over four times. Even though NASA tried to revive contact for weeks, it was without any success. An independent review concluded that the MGS team followed the correct steps, but they were inadequate, prompting the agency to overhaul procedures for future Mars missions.
Last contact with MGS might have been in 2006, but data provided by the spacecraft churned out further scientific results in the years that followed. As recently as 2016, NASA used in part data from MGS to provide an improved gravity map of the red planet. There might be more to come from all the data relayed by MGS as it accomplished all the objectives that it set out to achieve.
