The organisations will study specific areas of potential collaboration between the UK and US involving lunar science and exploration.
UK Science and Innovation Minister Malcolm Wicks said: "During my recent meeting with Nasa administrator Dr Michael Griffin, I was keen for the US and UK to co-operate on exactly this sort of exciting endeavour.
"I am delighted that this important agreement has been signed between our two space agencies which could provide an opportunity to harness the UK's world-class expertise in small satellite and robotic technologies."
The UK space sector is worth £4.8bn a year, and supports 70,000 jobs. It makes an overall annual contribution of £7bn to the UK GDP.
The joint agreement was signed in Washington and marks the successful conclusion of several meetings on potential collaboration.
In fear of future shortage - or in preparation for its own electric car project?
New Spectre microcode patches released by Intel to fix security flaws in Skylake, Kaby Lake and Coffee Lake CPUs
But if you're running anything older you'll have to wait
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Malware has been in circulation for more than a year