The future of space science in Europe rests on a launch pad at Cape Canaveral awaiting the push of a button this morning.

At the top of a $15 million Delta rocket to be fired into space at 9:53 a.m. today is a pair of statllites to study the impact of the solar wind on the magnetosphere that surrounds the earth like a great protective cloak. One is a $24 million International Sun-Earth Explorer built by the United States, the other a $20 million satellite with the same name put together by the 10-nation European Space Agency.

All eyes are on the Delta rocket and the smaller Europcan satellite it's carrying. A Delta failure would be the thrid time in a row an American rocket did not get a European satellite into orbit. A Delta failure this time could deal a fatal blow to European space science.

"If this flight fails it will be difficult to justify space science of any kind to the 10 governments who put up the money," said Dr. Edgar Page, director of space science for ESA. "It would put ESA in a very embarrassing financial situation."

On his way to Cape Canaveral the other day, the British-born Dr. Page said that ESA had already overspent its $70 million-a-year science budget this year as a result of the failure last April of an American Delta rocket to put a $100 million ESA satellite called GEOS (for Geodetic Earth Orbiting Satellite) into the right orbit.

On top of that loss came an explosion the evening of Sept. 13 that destroyed ESA's Orbital Test Satellite less than a minute after it had been lifted off the launch pad. The explosion lit up the sky, blew up a $42 million satellite and delayed indefinitely programs ranging from North Sea oil exploration to high energy physics tests in at least three European laborstories.

The rocket that blew up the OTS is the same as the Delts rocket that will attempt to launch the two International Sun-Earth Explorer statellites. Disasters like the OTS explosion are rare these days, which is why so many eyes are on today's launch.

"The embarrassment is even more acute for NASA than it is for us," Page said. "They're very aware of the seriousness in all this."

So much so that the National Aeronautical Space Administration Shipped two solid-fuel rocket motors called Castor II to the Marshall Flight Center in Huntsville, Als., for test firing Thursday night to see if they were fit. These engines, the same as those strapped to the sides of the Delta rocket that will be launched today, were prime suspects in the explosion of the Orbital Test Satellite last month. The engines fired flawlessly Thursday night.

"There's more at stake today than just the $20 million European Space Agency satellite on top of the Delta. Should today's launch carry the two ISEE satellites into orbit, a thrid satellite dubbed ISEE-C is to be launched next summer to complement the first two. ESA has another $10 million invested in the mstruments on the third satellite.

The puropse of all this is to get the three satellites into looping trajectories that take them as far away from the earth as 87,000 miles and as close in as 174 miles. Each satellite will measure the impact that the Sun's particle stream has on the earth's magnetic envelope at different spots in the envelope. It's an experiment never done before.

But if today's launch fails, the third launch may never getoff the ground and the entire experiment may be acrubbed.