Europe and Russia have decided to postpone their Mars rover mission.
The “Rosalind Franklin” vehicle was due to to launch to the Red Planet in July/August but engineers aren’t able to get the vehicle ready in time.
Because an Earth-Mars journey is only attempted when the planets are favourably aligned, the robot’s next opportunity won’t occur until 2022.
The Russian and European space agencies announced the delay on their websites on Thursday.
The set-back – the latest in a long series for this project – has been signposted for some weeks.
All the hardware is built, but there remains an intimidating list of outstanding checks that must be completed before the mission can be declared flight-ready.
Chief among the obstacles in the timeline are some underperforming electronics boxes in the Russian lander mechanism that would put the rover on the ground; and the overall flight software from Europe. Full testing required to achieve confidence in these items necessarily pushes the project beyond July/August.
Matters have been further complicated in recent days by the international coronavirus crisis which could start to disrupt engineering effort.
“We have made a difficult but well-weighed decision to postpone the launch to 2022,” announced Russian space agency (Roscosmos) Director General, Dmitry Rogozin
“It is driven primarily by the need to maximise the robustness of all ExoMars systems as well as force majeure circumstances related to exacerbation of the epidemiological situation in Europe which left our experts practically no possibility to proceed with travels to partner industries.”
European Space Agency Director General, Jan Wörner, added: “We want to make certain that we are 100% sure for a successful mission. We cannot allow ourselves any margin of error. More verification activities will ensure a safe trip and the best scientific results on Mars.”
Rosalind Franklin has been built to try to detect life, past or present, on the Red Planet.
Because of this, the rover and its instruments have been prepared to incredibly stringent levels of cleanliness. This status must now be maintained over the coming two years of storage.
The project’s industrial leader, Thales Alenia Space of Italy, will do this at its Turin factory.
What is unclear is how much the delay will cost.
The European Space Agency has worked out what it thinks is a fair price to store Rosalind Franklin but it has previously refused to publish the figure so as not to compromise negotiations with industry.
Esa has said it will not ask member states for additional funding and will use contingencies to get through the next two years.
First envisaged as a small technology demonstration mission, the robot vehicle was approved by European nations back in 2005, with a launch first pencilled in for 2011.
For much of its history, the rover project, codenamed ExoMars, has had to fumble through with budgets that were insufficient to maintain promised timelines.
At one stage, back in 2009, Esa decided to join forces with America to try to make the mission happen, only to see Nasa walk away three years later when its priorities changed.
That could have killed the project there and then, but for an offer from the Russians to fill the partnership position vacated by the US.
Even with this fresh impetus, however, the project continued to stumble. The Esa-Roscosmos 2018 target gave way to 2020. Now the launch date is being moved again.
The rover has been an important component of British space policy. The UK is the second biggest contributor to the ExoMars programme.
Graham Turnock, Chief Executive of the UK Space Agency, said: “ExoMars is an important, ambitious mission, with the UK-built Rosalind Franklin rover set to help us understand the past environment of Mars and search for evidence of life. To be successful, the mission must be carried out within an acceptable level of risk, so I support Esa’s responsible decision to delay the launch for further testing.”
and follow me on Twitter: @BBCAmos