The first chance for launch Saturday night was missed because of concern winds could blow propellant fumes from a second stage mishap into a populated area.

A fishing boat in the restricted waters down range, along the launch path, left the area several minutes before the end of the first launch window.

The second chance for launch was missed because of wind shear detected by weather balloons along the flight path.

The launch must take place by July 15th. After that date the Earth moves too far in its orbit around the sun for the Delta rocket to make it to Mars.

"We'd run out of gas before we got to Mars" was the way one manager put it.

The first Mars Exploration Rover, nicknamed "Spirit", was launched on June 10th and is already three million miles (4.8 million kilometers) away from Earth.

"Spirit" will land inside a crater on Mars on January 4, 2004.

Assuming the second explorer, nicknamed "Opportunity", launches successfully it will land on the opposite side of Mars on January 25th.

"Opportunity" is seeking to see how long there was water on the surface of Mars, a possible link to life on the Red Planet.

On Earth, life exists wherever natural sources of water are found, which accounts for the space agency's keen interest in ancient sources of Martian water.

The combined cost of the two missions is $800 million, according to NASA.

The six-wheeled rovers have the ability to scoop up soil and drill into rocks, then examine the samples. Data will be sent back to Earth for analysis by scientists at the Jet Propulsion Laboratory in Pasadena, California, where the mission control will be located.

The twin missions will join European and Japanese spacecraft already on their way to Mars.

Israeli, Palestinian negotiators invited to D.C. for talks
JERUSALEM (CNN) -- Palestinian Prime Minister Mahmoud Abbas, his team of negotiators and the Israeli team of negotiators have been invited to Washington for talks on the Middle East road map for peace, Palestinian sources told CNN Saturday.

The invitations came from U.S. national security adviser Condoleezza Rice, who is visiting the region in an effort to help jump-start the peace plan, the sources said.

When contacted by CNN, a White House spokesman said he couldn't confirm the invitations, but he added the White House was not debriefed by Rice after she met with Abbas Saturday.

Rice met with Palestinian officials on Saturday and will meet Sunday with Israeli officials.

Earlier Saturday, Palestinians and Israelis approached a key point on the road map to peace as Israel began planning to transfer security in Gaza back to the Palestinians and Palestinian militants prepared to announce a three-month cessation of attacks against Israelis.

After Hamas sources told CNN Friday that a cease-fire was imminent, Islamic Jihad leader Muhammed al-Hindi said Saturday that the truce "will be released in the next two days."

"Islamic Jihad and Hamas are just finalizing the details," he said. "If Sharon does not respect this truce, it will be finished."

A Palestinian militant source told CNN on Friday that the Palestinian militant factions will hand a cease-fire document -- that lists conditions -- to Abbas.

One condition is expected to be the lifting of the siege on Palestinian Authority President Yasser Arafat, who has been confined to his Ramallah compound for months, the source said.

Another possible condition is the release of Palestinian prisoners, the source added.

The Palestinian Authority leadership, which has been trying to broker a cease-fire with militant groups, has been saying there is an agreement in principle but that details need to be worked out.

Earlier this week, Palestinian and Israeli officials met at the U.S. ambassador's residence in Herzliya, near Tel Aviv, and reached an agreement in principle to transfer security in Gaza back to Palestinian control from the Israeli military.

Officials said the transfer could begin as early as Monday.

The White House applauded the agreement, saying it "represents a first significant joint step toward implementation of commitments made by each party at the Aqaba summit," held early this month in Jordan.

U.S. Secretary of State Colin Powell agreed.

"It is an early step. A lot more has to happen in the days ahead to make sure that this opportunity is not lost," Powell said in Washington.

Palestinian security sources said the plan would include the withdrawal of Israeli forces from northern Gaza and removal of almost all Israeli internal checkpoints in Gaza.

There is also a security deal for Bethlehem in the West Bank, in which Israel will pull out of that area after Gaza, the sources said.

An Israeli security source confirmed that Israeli and Palestinian commanders will start coordinating the details of the security change in Gaza and Bethlehem in preparation for the move.

He said the Palestinians promised to do their best to stop Qassam rocket attacks and incitement to terror, but did not go into detail about how the Palestinians would approach militant groups and their infrastructure.

The Israelis said they reached an agreement on "ticking bombs," or imminent attacks. When they have intelligence information about potential attacks, they would give it to Palestinians, the source said. But if Israel sees the Palestinians are not doing anything with the intelligence, Israel would then act as it sees fit.

Israeli Defense Minister Shaul Mofaz said in private meetings that the first and primary purpose of the road map will be accomplished with the security change, and it is in the Palestinians' interest, the source said.