PARIS — Britain’s minister for space said April 24 his government is protecting its space budget at a time of extreme austerity and that one way to do that is convince British defense authorities of the value of homegrown Earth observation satellite data.

David Willets, the U.K. minister for universities and science, said he chairs a Cabinet-level committee whose job is to bring civil and commercial Earth observation advances to the attention of the British Defence Ministry. Willets’ panel includes Peter Luff, Britain’s minister for defense equipment.

In a speech at a meeting in London during which an updated map of arctic sea-ice fluctuations was presented based on data from Europe’s Cryosat radar Earth observation satellite, Willets said many government departments remain ignorant of what Earth observation data can do. When it comes to radar data, the lack of knowledge is even greater.

“There are still many uses of Earth observation data that I don’t think have been fully appreciated within the commercial sector or the research community — or even, dare I say it, in all government departments,” Willets said.

Willets was instrumental in scraping together funding for a low-cost radar Earth observation constellation being developed by small-satellite specialist Surrey Satellite Technology Ltd. (SSTL), with the radar payload to be provided by Astrium Satellites Ltd., both of Britain.

The system, called NovaSAR, is intended as a constellation of four satellites weighing about 300 kilograms each and equipped with radar observing instruments with a ground-sampling distance of between 6 and 30 meters. The sensors would collect data with a swath width of 12-20 kilometers for the higher-resolution imagery and 750 kilometers for the lower-resolution images.

The British government has agreed to invest 21 million pounds ($34 million) to co-finance the first NovaSAR satellite with SSTL and Astrium. SSTL has estimated that the satellite would cost a total of about 45 million pounds, including launch in 2014. The full constellation would cost some 200 million pounds, including launch.

Willets cited NovaSAR as an example of how, even at a time of broad government spending cuts, the government is able to find extra funds for investments deemed worthwhile.

“The challenge now is to link what we do in civil and commercial space with the rather separate defense and security agenda,” Willets said, referring to the Cabinet committee.

Willets left the meeting before the 19-nation European Space Agency (ESA) was able to make its pitch for support for new Earth observation projects, which will be decided in November at a gathering of ESA government ministers.

Volker Liebig, ESA director of Earth observation, is asking agency governments to invest some 1.9 billion euros ($2.5 billion) over five years starting in 2013 in a broad package called the Earth Observation Envelope Program (EOEP). It is this program that developed Cryosat and other ESA Earth observation satellites.

Liebig said the loss of the altimeter aboard the Jason-1 U.S.-French ocean-altimetry satellite and the more recent failure — which may or may not be definitive — of the Envisat satellite have only increased the value of the Cryosat radar altimetry data.

Cryosat’s orbit, optimized for observing polar land- and sea-ice levels, takes it closer to the North and South poles than most other Earth observation satellites.

Launched in April 2010, nearly five years after the original Cryosat satellite was lost in a rocket failure, Cryosat 2 is delivering on its promise, according to Duncan Wingham, the mission’s principal investigator.

Wingham said Cryosat ultimately will deliver information on when the arctic region will be free enough of sea ice during the summer to permit the regular passage of maritime traffic and the exploitation of the region’s mineral and energy resources.

Wingham recently was named chief executive of Britain’s National Environment Research Council (NERC), which provides financial support to a broad range of science projects using funds provided by Britain’s Department of Business, Innovation and Skills.

For the 2011-2012 fiscal year, NERC has a budget of about 390 million pounds. The question is whether this budget, and its ability to fund space projects, will decline in line with the spending cuts already planned at the department that funds NERC.

Given his experience with Cryosat, Wingham’s appointment as NERC chief executive might be viewed as a boon to British space science.

But in an address to the Cryosat briefing, Wingham made clear that space projects will not be spared their share of the general sacrifice.

While saying the NERC “very strongly supports” the EOEP program of ESA, Wingham added: “We are all aware that we are in a time of austerity. Science has to make a contribution.”

With each new success like Cryosat’s, pressure builds to develop follow-on missions even as budget constraints add pressure from the opposite direction.

“The cost of these things must come down,” Wingham said of science satellites, adding that Cryosat, whose initial model cost about 150 million euros, is considered relatively inexpensive for a radar instrument “that is among the most sophisticated ever flown in space. Our budgets are going to be static for a considerable period into the future.”

NovaSAR, he said, may point the way to future systems that can combine low cost and high performance.

Peter B. de Selding was the Paris bureau chief for SpaceNews.