It’s almost Mars Month and from 17 July through 11 August the next biannual “launch window” to reach the Red Planet under the most favorable conditions of planetary alignment and energy expenditure opens again. United Launch Alliance (ULA) stands ready to deliver NASA’s Perseverance rover—a spacecraft not dissimilar to its predecessor, Curiosity, albeit equipped with a quite different scientific payload and, for the first time, a helicopter—as soon as 22 July. Over the last six decades, 45 discrete missions from Russia to the United States, from Japan to Europe and from India to China have been directed towards Mars, either to enter its orbit, to land on its dusty ochre surface or to conduct close observations. Agonizingly, almost half of all those missions failed during launch, during flight or just as they reached their destination.
As the world awaits the liftoff of its latest voyage to Mars, AmericaSpace offers a glance back across six decades of U.S. fascination with a planet which bears such close similarities to our own and may, someday, even be capable of supporting human life.
It would be remiss to begin this trudge down memory lane without tracing the United States’ failures to reach Mars. And with at least five Soviet launch failures in the first half of the 1960s, NASA can have been in no doubt of the hazards involved when Mariner 3 lifted off atop an Atlas-Agena booster from Launch Complex (LC)-13 at Cape Canaveral on the afternoon of 5 November 1964. Laden with a single television camera to acquire 21 images, a cosmic-ray detector, a cosmic-ray telescope, a magnetometer and a trapped radiation detector, Mariner 3 was tasked with an eight-month voyage through interplanetary space, after which it would photograph the Red Planet for the first time and examine the composition of its atmosphere through radio occultation.
Sadly, it never got that far. Ascent out of the Cape seemed nominal and the Agena upper stage satisfactorily completed its “burn” to inject Mariner 3 onto a trans-Mars trajectory. An hour after launch, the spacecraft’s instruments were up and running, but it remained unclear if the four solar array paddles had deployed. Ground controllers turned off its rate gyroscopes to converse power whilst they investigated the problem and it gradually dawned that Mariner 3 had improperly separated from the rocket’s payload shroud. Commands were issued to manually jettison the shroud, but nothing happened. Hopes of using the spacecraft’s own engine to blow the shroud away came to nothing when, eight hours after leaving the Cape, Mariner 3’s batteries died and it fell forever silent and heliocentric orbit.
Similar misfortune befell Mariner 8, when it departed the Cape’s Launch Complex (LC)-36A atop an Atlas-Centaur vehicle on 9 May 1971. By this time—as tomorrow’s AmericaSpace feature will show—the United States had succeeded in reaching Mars on three occasions, and it was perhaps with an air of hesitant optimism that Mariner 8 was sent on its journey to orbit the Red Planet for at least 90 days, working in conjunction with its near-identical twin, Mariner 9. The two spacecraft would map 70 percent of Mars’ surface, measure the composition, density, pressure and temperature of its atmosphere and the nature and topography of its undulating surface.
The Atlas core performed admirably, it seemed, after which the Centaur upper stage began its lengthy burn to deliver Mariner 8 out of Earth’s embrace. Then, with scarcely any warning, it started oscillating wildly in pitch and its controllability deminished to zero. A hundred seconds into its burn, the Centaur fell silent due to starvation induced by the effects of tumbling. Upper stage and payload separated about 900 miles (1,500 km) downrange of the Cape and plunged into the watery depths of the Atlantic Ocean, some 350 miles (560 km) north of Puerto Rico. To date, Mariner 8 is the most recent U.S. Mars-bound space mission to be lost in an outright launch vehicle failure.
It would be more than two decades before another American voyage to the Red Planet sustained catastrophic misfortune and, in the case of Mars Observer, it would come tantalizingly close to reaching its destination. Launched atop the last Commercial Titan III booster from the Cape’s Space Launch Complex (SLC)-40 on 25 September 1992, the spacecraft’s 11-month trek across interplanetary space proved uneventful. It was intended that Mars Observer would spend at least one Martian “year”—some 687 Earth-days—comprehensively examining the planet’s surface, atmosphere, climate and magnetic field. But only days before it was due to enter orbit around Mars, the spacecraft vanished like a blip from a radar screen.
It was meant to arrive in the second-to-last week of August 1993, entering a highly-elliptical orbit which would be maneuvered over the next four months into a near-circular path at an altitude of 234 miles (377 km). Inclined 93 degrees to Mars’ equator, it would sweep low over the poles and bring a comprehensive imaging toolkit to bear on this alien world. A powerful camera, laser altimeter, thermal emission spectrometer, infrared radiometer, gamma-ray spectrometer, magnetometer and radio-science hardware would achieve more in terms of understanding our close planetary cousin than any earlier mission had ever done. Spectacular images of Mars shuttered in late July 1993 whetted the appetites of many planetary scientists for what was to come.
But what actually came was calamity. Late on 20 August, contact with Mars Observer abruptly went dead, for no apparent reason, and repeated efforts to initiate communications came to nought. Five months later, a Naval Research Laboratory (NRL) investigation concluded that the most likely cause of the spacecraft’s demise was a ruptured fuel pressurization tank in its main propulsion system. Hypergolic monomethyl hydrazine may have leaked past valves during the 11-month cruise and inadvertently mixed with nitrogen tetroxide. The leaking fuel could then have induced an extremely high spin-rate and probably damaged critical components aboard Mars Observer itself.
Since then, two more U.S. spacecraft have failed whilst agonizingly close to reaching their destination. With weeks of one another, in the fall of 1999, Mars Climate Orbiter and Mars Polar Lander were catastrophically lost in circumstances which remain unclear.
The Climate Orbiter rose from Earth on 11 December 1998, riding a Delta II out of Cape Canaveral’s LC-17A and onto a 9.5-month journey which saw it travel over 416 million miles (669 million km) to the Red Planet. It was charged with determining the distribution of water on Mars, monitor daily weather and atmospheric conditions, record changes on the surface caused by wind or other effects and investigate past climate change. The cruise proceeded without apparent incident, but on 23 September 1999 communications with the Climate Orbiter suddenly vanished as it began the process of inserting itself into orbit around Mars. It pressurized its fuel and oxidizer tanks and fired its main engine for what should have been a 16-minute burn. Contact was lost four minutes into the burn.
Seven weeks later, a mishap investigation board reported that Lockheed Martin-provided ground software had yielded altitude data in U.S. customary units, whilst a NASA-supplied system provided results in metric units. Computations from a trajectory correction maneuver, executed on 15 September 1999, predicted that Climate Orbiter’s altitude upon orbit insertion would be far lower than expected. Concerns from engineers about the discrepancy were dismissed and another trajectory correction maneuver—which might have saved the mission—was ultimately not pursued.
It was a sad and unnecessary loss of a valuable mission, but it was not to be the last in 1999. Only weeks later, Mars Polar Lander also vanished without trace. This spacecraft had been launched via a Delta II booster from the Cape’s SLC-17B in January 1999. It would alight at Planum Australe—near the Martian south pole—and utilize a robotic arm to dig into the layered terrain of a hitherto-unexplored polar landscape and deploy microphones for soil-moisture tests. The spacecraft would search for evidence of the ancient polar climate and derive an improved understanding of current and ongoing seasonal change at Mars’ higher latitudes, including the exchange of water vapor between the atmosphere and the surface. Its two Deep Space-2 probes would be released at high velocity during descent to impact the surface and take measurements at a depth of up to 3.3 feet (1 meter). But as with Mars Observer before it, the fate of Polar Lander and Deep Space-2 was sealed as the spacecraft approached the Red Planet.
The investigation into the loss of Climate Orbiter had led to the implementation of new procedures for Polar Lander to warm up its descent engine, lest cold temperature impair its performance. Shortly before arrival at Mars on 3 December 1999, a final trajectory-correction maneuver was executed and the grapefruit-sized Deep Space-2 probes—appropriately nicknamed “Amundsen” and “Scott”, in honor of Earth’s own pioneering polar explorers—were meant to be jettisoned during descent to impact and penetrate the surface at 400 mph (640 km/h). They would conduct the first-ever direct measurements beneath the surface of another planet.
The period from Entry Interface to contact with the Martian surface was predicted to last only 5.5 minutes, as Polar Lander headed inbound at 15,400 mph (24,780 km/h), enduring gravitational stresses 12 times greater than at sea-level here on Earth and temperatures of up to 1,650 degrees Celsius (3,000 degrees Fahrenheit). Touchdown was anticipated at 12:14 p.m. EST, with the first signal from the spacecraft expected at 12:39 p.m. But it never came. Managers were initially “confident” that Polar Lander had survived, but that confidence evaporated as neither the spacecraft nor Deep Space-2—whose probes were predicted to have hit the surface about 35 miles (60 km) north of the lander itself—were contactable. By mid-January 2000, the mission was declared lost.
Given the near-total lack of telemetry data, investigators had little to work with and their report in March concluded that it most likely the Polar Lander’s main engine had shut down too early, “resulting from the vulnerability of the software to transient signals”. In all probability, the spacecraft incorrectly identified vibrations from the deployment of its landing legs as touchdown on the surface and its software shut down the engine at an altitude of perhaps 130 feet (40 meters), too high to be survivable. Alternatives included an unsurvivable landing location, failure of Polar Lander’s protective “backshell”, heat shield or parachute and inadequate pre-launch hardware testing.
These five U.S. mission failures—two failed launch attempts and three failures when in close proximity to Mars itself—underscored the reality that getting to the Red Planet was a painfully complex undertaking. Additionally, no fewer than eight Soviet missions failed during their launch phases between October 1960 and May 1996 and eight others failed as they neared Mars or upon contact with its surface. China also lost its first Mars-bound probe, Britain’s Beagle-2 landed but suffered a power supply failure and Europe’s Schiaparelli lander also crashed during descent. All told, of the 45 missions which have so far taken aim on Mars between October 1960 and May 2018, no fewer than 22 have suffered outright failures. When it comes to voyaging to the Red Planet, the gremlins, it seems, are waiting at every turn.
But don’t despair. Fifteen U.S. missions from Mariner 4 in November 1964 to InSight in May 2018 have comprehensively examined its surface, weather and climate from orbit, placed landers and rovers onto its inhospitable ochre-hued terrain and established a communications network to support future exploration. When Perseverance arrives in February of next year, it will carve its own niche in history by deploying the first-ever helicopter on an alien world. In the second part of this three-part article, AmericaSpace will look back at the legacy of the United States’ successes at Mars and their inherent meaning as we humans take aim on the Red Planet for future exploration and colonization.
The second part of this article will appear later this week.