NASA scientists rejoiced at ``pretty damn good'' test photos from the Magellan probe today but also grappled with communications difficulties as the spacecraft circled Venus. Fifteen hours after the spacecraft lost contact with Earth on Thursday evening, the signal was re-established. But the signal failed again at midday and was expected to continue to be a problem until scientists could send Magellan new instructions on how to properly aim at Earth, officials said. Meanwhile, project manager Tony Spear said the test pictures collected from the spacecraft's radar mapper before the problems developed had produced ``some raw images that looked pretty damn good.'' He said NASA will release the first pictures on Monday instead of waiting until September. Thursday's test returned far more pictures than expected, including several so-called ``noodles,'' or areas of the planet about 1,000 miles long by 15 miles wide, project scientist Steve Saunders said. The pictures show ``lava flows and faults and fractures and cinder cones with craters in the top,'' Saunders said. Scientists at NASA's Jet Propulsion Laboratory were concerned when they did not hear from Magellan as expected at 8:32 p.m. Thursday. But they stressed that the spacecraft is loaded with computer programs that automatically help it find Earth if contact is lost. Originally, scientists had expected that the outage would continue until this evening. But late this morning, as scientists were were conducting a news conference about the problem, Magellan manager Steve Wall rushed in with word that NASA's Deep Space Network station at Goldstone, Calif., had re-established contact with the spacecraft and locked onto its signal. ``It is Magellan,'' Wall said. ``The spacecraft looks healthy.'' The second loss of contact a short time afterward was not entirely unexpected, Spear said. Scientists now expect the spacecraft to be in and out of touch until controllers can send it new instructions on how to properly aim at Earth, he said. However, the second signal loss blunted some of the sense of relief at hearing from Magellan after the overnight silence. Wall said engineers had been out of contact with the spacecraft Thursday night as it fixed on two stars, a procedure Magellan routinely performs to make sure it is pointed properly. NASA should have heard from Magellan at 8:32 p.m. PDT Thursday when this ``star calibration'' was completed, but ``we did not re-establish contact,'' JPL spokesman Jim Doyle said. The last previous radio contact with the craft had been at Deep Space Network stations at Goldstone and in Australia. ``The assumption is that after it made a star calibration, it looked at the wrong star and then couldn't point back to Earth accurately,'' Doyle said. ``Then, the contact was lost.'' Project officials believe the spacecraft detected an unknown onboard problem and entered a protective ``safing mode'' in which it orients itself toward the sun so its solar array will continue to receive power and find a guide star, said Doyle. From that position, it was programmed to automatically start a routine of locating the sun, then searching for Earth, Wall said. The problem with Magellan comes in the wake of NASA's troubles with the flawed Hubble Space Telescope and with hydrogen fuel leaks that temporarily grounded the space shuttle fleet. Magellan's formal mission to map the surface of Venus is supposed to start Aug. 29. Contact was lost after Magellan started a two-day test meant to make sure the spaceship's radar can make pictures of Venus and to adjust the radar waves so the pictures are focused, said lab official Ed Sherry. Venus, the second planet from the sun, is covered by thick clouds that prevent optical cameras from seeing its rugged landscape. Magellan's $744 million mission will use radar to penetrate the clouds, then collect the reflected waves to make the best maps and pictures yet of Earth's nearest planetary neighbor. The spacecraft was launched from the shuttle Atlantis 15 months ago and went into orbit around Venus a week ago after a roundabout 948-million-mile journey. At least 20 U.S. and Soviet spacecraft have visited Venus, including some that landed and photographed a small area of landscape. Magellan will yield a global map. Its radar was designed to distinguish surface features as small as two football fields, a level of detail 10 times better than in pictures made by radar on two Soviet spacecraft that were launched in 1983.
