Parachute Troubles for ExoMars 2020, With Launch Less Than a Year Away

The ExoMars 2020 project suffered another parachute test failure last week.  The European-Russian mission to land a rover on Mars is scheduled for launch next summer, so time is running short for the international team to solve whatever is causing the parachutes to rip apart during high altitude drop tests.  Despite all the buzz about sending humans to Mars, just trying to land robotic probes continues to demonstrate the challenges involved.

The European Space Agency (ESA) and the Russian state space corporation Roscosmos are partners in the ExoMars (Exobiology on Mars) project.  The first portion of the project launched in 2016:  the ExoMars Trace Gas Orbiter (TGO) and the Schiaparelli experimental lander.  TGO successfully reached orbit and continues to send back data and serve as a communications relay between Earth and two NASA spacecraft on the surface (Curiosity and InSight).

Schiaparelli, however, crashed on landing. The problem was not parachutes in that case, but bad data from an inertial measurement unit.  Its purpose was to gain experience in preparation for the ExoMars 2020 lander/rover combination. Roscosmos and Russia’s Space Research Institute (IKI) are responsible for the lander, named Kazachok.  ESA is responsible for the rover, named Rosalind Franklin after the renowned British chemist who contributed to unraveling the double helix structure of DNA.  The rover is being built by Airbus Defence and Space in Stevenage, UK.

ESA also is responsible for the carrier and descent modules that will deliver the lander and rover to Mars.

The United States is the only country to land on Mars repeatedly — eight of nine attempts since 1976 have been successful.  Every time, NASA stresses how difficult it is, however, especially the entry-descent-and-landing (EDL) sequence where the spacecraft enters the Martian atmosphere and must slow down enough to land safely.  There are several methods for the landing itself, but parachutes are critical during descent.  NASA coined the phrase “seven minutes of terror” to describe the EDL process for the Curiosity rover that arrived at Mars in 2012.  NASA’s Mars 2020 mission will use the same profile.

The ExoMars 2020 EDL process is different from Curiosity’s, but still challenging.  The descent module will have two sets of parachutes, each comprised of a drogue chute and a main chute.  The main parachute has a diameter of 35 meters, the largest for any Mars mission according to ESA.

The main parachute deployed properly last year during a test where it was dropped from a helicopter at an altitude of 1.2 kilometers.  But on May 28, all four parachutes were dropped from a stratospheric balloon at an altitude of 29 kilometers. Both main parachute canopies suffered damage.

Design changes were implemented and a second test of the main parachute was conducted on August 5, but similar damage was observed.  Francois Spoto, ESA’s ExoMars Team Leader, said it was “disappointing,” but the team remains focused on finding and fixing “the flaw in order to launch next year.”

The launch window is July 25 – August 13, 2020, with Mars arrival in March 2021.  Earth and Mars are aligned properly only every 26 months to permit direct launches from one to the other and some windows are better than others.  Russia will launch the spacecraft on a Proton rocket.

NASA is providing an astrobiology instrument for the rover — Mars Organic Molecule Analyzer (MOMA).  Originally NASA intended to be a major partner in ExoMars, but had to withdraw when the Obama Administration proposed deep cuts to NASA’s planetary exploration program.  Russia stepped in to replace the United States as ESA’s primary partner.  NASA later decided to build Mars 2020 using some of Curiosity’s backup hardware and new scientific instruments.

Russia has launched a number of missions to Mars since the 1960s, mostly orbiters, but it sent landers at least four times.  Mars 2 and 3 were orbiter/lander combinations, Mars 5 and 6 were flyby/landers.  Only one, Mars 3, survived the trip to the surface. It transmitted data for just 20 seconds before falling silent.

ESA’s Mars Express orbiter, launched in 2003, took along a very small (2-meter diameter) British-built lander, Beagle 2.  It separated from Mars Express, but contact was lost after its scheduled landing.  Its fate remained unknown until 2015 when it was discovered in images from a high resolution camera on NASA’s Mars Reconnaissance Orbiter.  It landed intact, but was unable to communicate because solar panels did not deploy properly.

NASA’s Mars 2020 and ExoMars 2020 will have company.  The United Arab Emirates (UAE) and China also are planning missions.  The UAE’s Hope is an orbiter.  China plans to launch an orbiter/rover, but it requires China’s new Long March 5 rocket, which has not yet returned to flight after a 2017 failure.