NASA’s Office of the Chief Technologist has announced three space propulsion missions to develop technology that might be used on future science probes, at a combined cost to the US taxpayer of $175 million.

The three missions are:

A demonstration in which lasers will be used to communicate data from a spacecraft; currently done via radio waves. It should launch in four years.

An atomic clock based on a mercury atom that will test ultra-precise timing in deep space, to be ready to launch in three years.

A demonstration of a solar sail seven times larger than any yet deployed in space, also to be launched in three years. The current record is held by the Japan Aerospace Exploration Agency JAXA’s IKARUS (pictured), a 100 square meter sail mission that was extended in January 2011.

While two of the three missions –- the laser demo and the atomic clock — are based at NASA centers, the third is being led by a company, L’Garde Inc, in Tustin, California, which NASA says will work with the National Oceanic and Atmospheric Administration (NOAA), which monitors space weather. “We’re very excited. We’ve spent a lot of time investigating this and to finally have a sail demonstration in space is pretty far-reaching,” says engineer Nathan Barnes, principal investigator on the mission, which is dubbed “Beyond the Plum Brook Chamber,” after the world’s largest vacuum chamber at NASA’s Glenn Research Center in Sandusky, Ohio, where the company deployed a test solar sail in 2005. Solar sails are light and are expected to be extremely cost-effective forms of propulsion for smaller space missions. Barnes says the L’Garde demo has been budgeted in at only $16 million of the figure NASA announced.

The laser communication mission is more expensive than that, because its technology is entirely unproven, says David Israel of NASA’s Goddard Spaceflight Center in Greenbelt, Maryland, who did not feel free to disclose the exact budget. He says optical communications between satellites would result in much higher data rates than radio communications do, if only the technology could be made reliable. “There will still be radio links on spacecraft for some time to come but some day optical may replace it,” he says.

Bill Nye, the executive director of the Planetary Society, a non-profit organization for space-based research in Pasadena, California, that is preparing to launch a 32-square-meter solar sail, says he is surprised by the large combined budget of the selected missions. The Planetary society had competed for the solar sail slot with a proposed budget of only $5 million. “Ours was so modest that maybe it got overlooked,” says Nye. “We’re disappointed.” He’s waiting to receive reviews from NASA that would explain the agency’s decision.