The chief scientist on Europe's lost Cryosat mission says the spacecraft must be rebuilt.
Duncan Wingham told BBC News the data the satellite was seeking on the state of the Earth's ice cover was essential to our understanding of climate change.
"You have to see [the replacement cost] in context," he said. "There is a cost in not knowing what is going on and in the end that's an even larger cost."
Cryosat fell into the Arctic Ocean shortly after Saturday's blast-off.
It was riding atop a Rockot vehicle from Russia's Plesetsk Cosmodrome in northern Russia. Early investigations indicate a failure with the onboard flight-control system.
The error meant that the separation between the rocket's second and third stages did not occur, denying the satellite the final boost it needed to reach polar orbit.
Cryosat is thought to have fallen into an area off Russia's northern coast known as the Lincoln Sea.
"It's a blow; there's no way of avoiding it, it's a big disappointment," Professor Wingham said. "Three years is about the minimum length of time needed to put a replacement mission together."
1- 1502 GMT: Cryosat launches from Plesetsk, northern Russia
2 - 1504: First stage separation
3 - 1508: Second stage separation due - but scientists believe that a software error meant this did not happen. The rocket plunged back to Earth when its fuel ran out.
The University College London researcher first proposed the Cryosat mission in 1998.
It was the first of the European Space Agency's Earth Explorer missions - relatively low-cost projects designed to obtain quick answers to important environmental questions.
In Cryosat's case, it would have provided the best data yet on ice extent and volume. This would have given scientists a definitive picture of the rate of thinning seen in Arctic sea ice and enabled them to improve computer models of climate change.
The production schedules of the Explorers have been speeded up through the incorporation of off-the-shelf-design on some components and by avoiding the standard practice of building a full "engineering model". Early testing is done in computer simulations.
This approach substantially reduces costs, but the £90m (135m euro) price of Cryosat is not insubstantial when Esa member states also have other science projects competing for finite funds.
An important indication on whether Europe will approve a "Cryosat 2" could come at the agency's December meeting of member states. Science and research ministers will take important decisions across a range space activities, including the despatch of another lander to Mars.
Cryosat faces competition from other science projects
"The agency has already announced that it will look at ways of doing the mission again," said Professor Wingham. "The science we are trying to do is very important and we need to find out what is going on in the Arctic."
The Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) is the next in the Earth Explorer series. This has been booked to ride a Rockot vehicle next year but will now be "on hold" until the events of Saturday are fully understood.
Russian authorities have set up a board of inquiry to look into the cause of the failure and it is expected to report its findings in the next few weeks.
Esa says it continues to have confidence in the Rockot launcher, which had six successful launches prior to Saturday.
But a spokeswoman for Esa's European Space Research Institute in Frascati, Italy, said the agency would now subject the Rockot launch system to close scrutiny.
"We would first want to see what the outcome of the investigation will be before we take any final decision on how we go about the [next launches] and whether we would accept any delays and so on," she explained.