Skip to the timeline
Let's go to Mars

Europe makes orbit and loses Schiaparelli

One second of saturated gyro data convinced a lander it was already underground. It cut its parachute at 3.7 km and hit Mars at 540 km/h.

A grainy grey overhead view of Martian ground with a dark smudged blast scar around a small black point of impact, and a thin curved mark a short distance away.
The Schiaparelli impact site in Meridiani Planum, photographed on 25 October 2016 by the HiRISE camera on NASA's Mars Reconnaissance Orbiter, the first HiRISE view of the site after the 19 October landing. The small black point where the module hit the ground at 540 kilometres per hour is about 2.4 metres across; the dark curving line to its northeast is unusual for an impact, and the HiRISE team did not attempt to explain it. · Image: NASA/JPL-Caltech/Univ. of Arizona, cropped by Del Pacino

Two European spacecraft arrived at Mars on 19 October 2016. The Trace Gas Orbiter burned its main engine for 139 minutes into orbit; Schiaparelli, the 577-kilogram demonstrator lander it carried, hit the ground at 540 kilometres per hour.

The descent began normally: entry at 21,000 km/h, parachute at 12 kilometres and 1,730 km/h, heat shield off at 7.8 kilometres. The inflating parachute then swung the module harder than modelled, saturating its inertial measurement unit for about one second. The corrupted attitude, fed in with the radar altimeter, produced a negative altitude, and the lander jettisoned parachute and back shell, fired its braking thrusters 3 seconds instead of 30, switched on its surface systems and fell from 3.7 kilometres. NASA's Mars Reconnaissance Orbiter photographed the impact site next day. ESA's inquiry of 24 May 2017 listed four root causes: parachute dynamics inadequately modelled, inadequate handling of a saturated IMU, failure-detection logic that never flagged an impossible altitude, and loose oversight of subcontractors and hardware acceptance.

The orbiter worked. After a year of aerobraking to circularise its orbit, TGO began science in April 2018 with two spectrometer suites, ACS and NOMAD, measuring trace gases down to parts per trillion, far below anything flown at Mars before, and aimed above all at methane.

Methane survives only a few hundred years before ultraviolet light breaks it up, so whatever is there now was released recently, by geology or biology, though the gas itself may be far older. Curiosity's tunable laser spectrometer in Gale Crater reported a background near 0.41 parts per billion with a seasonal swing, plus spikes of about 7 ppb over 2013–14 and 21 ppb in June 2019. TGO looked from April to August 2018 across both hemispheres and found nothing: upper limit 0.05 ppb, best sensitivity 0.012. The contradiction is unresolved; explanations proposed include night-time release at Gale diluted by day, a source aboard the rover, and an unidentified fast destruction mechanism.

ExoMars was designed as two missions. The second, the drilling rover Rosalind Franklin, lost its Russian launcher and landing platform when ESA severed ties with Roscosmos in 2022; ESA now targets 2028.