In Brief:

• Shuttle Discovery now first in line for launch
• NASA sponsors "Mars Millennium" Webcast Tuesday

September 28, 1999
Web posted at: 9:26 a.m. EDT (1326 GMT)

(CNN) -- NASA managers have given a Hubble telescope repair mission priority over an Earth-mapping mission for the agency's next human space launch due to faster progress in inspecting wires aboard the shuttle assigned to the former task.

Shuttle managers now have set their sights on a Kennedy Space Center launch for Discovery and the repair mission no earlier than November 19.

Initially, Endeavour was set for a September launch with the radar mapping mission, with Discovery to follow in October.

But the area under the liner of Discovery's payload bay was easier than similar areas in Endeavour for technicians to reach during wiring inspections of all four shuttles prompted by a short circuit during a July shuttle launch.

Endeavour now will be ready for launch no earlier than December. Managers will keep meeting to assess the progress of repairs and adjust launch dates accordingly.

Atlantis was moved to a bay in the Orbiter Processing Facility at KSC where it will undergo inspections next. Columbia was ferried to Palmdale, California, atop a modified Boeing 747 this weekend for long-term maintenance at a Boeing facility.

NASA formed a panel last week to review the safety of shuttle maintenance work in response to the short circuit that has resulted in a suspension of shuttle flights for four months.

An exposed wire and burred screw made contact during the July 23 launch of Columbia, causing the short that could have put astronauts' lives at risk if another had followed. Launch vibrations caused the wire to bump against the screw and the current was derailed.

Inspectors think the wire lost a bit of its insulation, possibly years ago, when a technician leaned against the wire, rubbing it against a burred screw.

The short circuit occurred just seconds after Columbia lifted off and shut down power to two of the three engines on the shuttle. Back-up systems took over, but a second short would have forced an emergency landing in Florida or Africa.

After Columbia landed, shuttle managers called for a review of 100 miles of wiring in each shuttle to prevent future shorts. That involved removing payloads from some of the shuttle's cargo bays and slowly taking the space planes apart.

(CNN) -- The design for a Mars community for humans will be featured during a NASA-sponsored Webcast set for 1 p.m. EDT on Tuesday.

Four NASA scientists are set to participate in a roundtable to answer student questions submitted remotely and from the event site, NASA's Ames Research Center in California.

"The scientists will cover four questions about Mars," said Sandy Dueck, Mars Millennium Webcast moderator.

"The questions are: What is Mars like right now? Why are we so interested in Mars? What are the current missions planned for Mars? When and how will human beings explore Mars, and what might they do there?"

Featured researchers include Christopher McKay, a planetary scientist whose current research focuses on the evolution of the solar system and the origin of life, and his colleague Kelly Snook, who analyzes Mars data and is working on a possible mission to Jupiter's moon, Europa.

Also participating are Robert Anderson, the science mission planner for the Mars 2001 mission, and David Seidel, an outreach supervisor. Both are from NASA's Jet Propulsion Laboratory in California.

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