Some scientists suggest carbon-based molecules may have been destroyed before the Viking landers could find them.

The letter expresses support for the president’s proposed strategy for NASA and criticizes cuts contained in a NASA authorization bill now before the House.

NASA is revisiting the question of what rocket to build next and whether solid motors will be part of it.

This chronicle of the innovative Voyager mission also ponders the nature and meaning of exploration itself.

Scientists say that the shrinking may have occurred over a billion years, and that the Moon will not shrink out of view in the future.

Courtney Stadd, NASA’s former chief of staff, pleaded guilty Wednesday in federal court in Gulfport to conspiracy in a case stemming from a $600,000 contract for Mississippi State University, a client of his consulting firm.

With a replacement cooling pump successfully installed, the International Space Station’s electrical systems were largely expected to be returned to the usual configuration by Aug. 17.

A new study contradicts some recent reports that say the Moon had water at the time of its formation.

An unexpected ammonia leak derailed a marathon spacewalk to replace a faulty coolant system pump aboard the International Space Station.

If the International Space Station were ever abandoned, the United States’ human spaceflight program would lose one of its last remaining reasons for being.

A spacewalk to replace a broken coolant pump on the International Space Station has been delayed another day to Saturday morning.

On the Web, whispers of the next big discovery quickly become roars, even when there’s nothing to roar about.

Scientists may have identified three specks of interstellar dust that just flew into the solar system, a prospect that was initially deemed hopeless.

Two astronauts are scheduled to venture out early Friday to begin repairs on the cooling system of the International Space Station.

One of two coolant systems aboard the International Space Station malfunctioned, setting off alarms.

The discovery that Titan’s lakes are evaporating, at least in the Southern Hemisphere, suggests that there are active weather and geological cycles analogous to those on Earth.

The data from two separate experiments at Fermilab narrow the range in which the Higgs boson, if it exists, must be hiding.

A huge ball of burning gas may be the heaviest star ever found.

President Obama planned to spur a commercial market for the launching of people into space and direct the agency to continue developing its own rocket.

Images suggest that Mercury was volcanically active well into its middle age, given that it formed 4.5 billion years ago with the rest of the solar system.

A string theorist is not tethered to the notion of gravity, saying the force is a consequence of thermodynamics.

The outline, which has White House support, includes investment in commercial partners and development of new spacecraft.

NASA did nothing improper in removing the head of its return-to-the-moon program, the agency’s inspector general told Congress on Tuesday.

A subatomic particle that anchors atoms and is the building block of all ordinary matter is 4 percent smaller, an experiment shows.

The bill would reverse large swaths of President Obama’s proposed changes to NASA’s human space flight program.

The launching of a new Air Force space surveillance satellite was delayed due to a software problem in a rocket similar to the one that will lift the satellite into orbit.

In a shift from particle physics to photon science, an outdated accelerator in Menlo Park, Calif., was converted into the world’s brightest X-ray laser.

Japan’s hopes for a bigger share of the global market for satellites and other space infrastructure may rest on an asteroid mission with only qualified success.

The end of the space shuttle era will be extended until early 2011.

A new space policy renounces the unilateral stance of the Bush administration, emphasizing global cooperation.

Workers are caught in a conflict between Congress, which has banned NASA from canceling any part of a new lunar mission, and program managers who have been told to scale back.

A Congressional committee is demanding that the space agency provide a host of records related to its budget request for 2011.

As excitement builds about a list of stars newly suspected of harboring planets, some astronomers are questioning why the Kepler team is holding back some of the data.

A Russian rocket carrying two astronauts from the United States and one from Russia lifted off successfully from Kazakhstan, bound for the international space station.

NASA has scaled back the work it will do in the coming months on its program to return astronauts to the moon, telling contractors to set aside money to cover its potential cancellation.

A Nevada company is preparing the solar system’s first private space station.

NASA officials presented their latest views on carrying out President Obama proposed space policy.

A privately developed rocket that may eventually carry NASA astronauts to space took off Friday afternoon in what appeared to be an almost flawless flight.

The Kavli Prizes acknowledge their work in astrophysics, nanoscience and neuroscience.

A multimillionaire’s newest rocket is poised to blast off Friday from Cape Canaveral in a trial run of what the pioneering company hopes to do for NASA once the shuttles stop flying.

A telescope will be sent a million miles from Earth to collect images that have been traveling since nearly the beginning of the universe.

With a train’s delivery of solid-fuel booster segments to Florida, the program has just two trips left.

There are two striking features on the Northern ice caps of Mars that have intrigued scientists.

NASA scientists said the body, 1.5 times the diameter of Earth, orbits a Sun-like star 2,000 light-years away.

Mary Roach’s book “Packing for Mars” delights in the fringe material associated with astronauts’ life in space.

Highlights of Mary Roach’s look at the way humans adapt to spacefaring include zestful accounts of human-waste disposal, body odor control and astral sexual desire.

An exhibition at the National Air and Space Museum features 148 extraordinary photographs of moons and planets.

How did you celebrate World U.F.O. Day? You didn’t? Dang.