WASHINGTON NASAannounced the cancellation of a planned mission to the jovian moon Europa butalso unveiled a new series of planetary exploration probes during a Feb. 4briefing on the agencys 2003 budget request.

The termination ofthe Europa Orbiter mission was among the surprises in U.S. President George W.Bushs budget request, which would provide $15 billion to NASA next year, a 1.4percent increase over 2002.

NASA AdministratorSean OKeefe said the request supports the Bush administrations goal ofrefocusing NASA on research and development and addressing managementshortcomings. Well have no difficulty whatsoever defending the content ofthis budget and I am confident the Congress will see it that way as well,OKeefe told reporters at the briefing at NASA headquarters here.

The budget includesmodest increases for all major NASA enterprises except for human space flight.If Bushs budget is approved, the space shuttle and international space stationprograms would see their budgets decline by $624 million collectively.

The budget supportsfour space shuttle missions to the space station each year. Additional shuttlemissions for activities such as Hubble Space Telescope servicing would have tobe added to the mix and funded as the need emerges, NASA officials said.

Documentsaccompanying Bushs 2003 budget request, released by the White House Office ofManagement and Budget Feb. 4, highlight NASAs Outer Planets, internationalspace station and space shuttle upgrade programs as ineffective and in needof reform.

For example, thebudget documents say the Outer Planets program, which included plans to sendspacecraft to Pluto and Europa cannot be implemented as planned because somemission cost and schedule estimates have nearly doubled.

NASA cited excessivecost growth in canceling the Europa Orbiter mission and for the second straightyear the agency is not requesting funding for the New Horizons Pluto-KuiperBelt mission. Funding for the Pluto mission was inserted into NASAs 2002budget by Congress.

The Outer Planetsprogram is being reformulated into what NASA is calling the New Frontiersprogram. New Frontiers missions will be capped at $650 million and havedevelopment cycle times of 48 months.

Each New Frontiersmission will be selected through an open, peer-reviewed competition modeledafter NASAs Discovery series of planetary missions. The Bush administrationheld up the Discovery program as one of the few effective ones at NASA.

NASA space sciencechief Ed Weiler said the agency will issue its first New Frontiers announcementof opportunity this spring, with selection targeted for 2003.

In Earth science, theBush administration has decreed that imagery that for decades has beencollected by NASAs Landsat satellites will be procured commercially in thefuture. That means NASA cannot buy a spacecraft to replace Landsat 7, which waslaunched in April 1999.

Ghassem Asrar, NASAsassociate administrator for Earth Science, said NASA has four proposals underevaluation for the Landsat Data Continuity Mission and plans to pick two orthree finalists this summer.

Also announced at thebriefing was a NASA plan to resume a long-suspended pursuit of new in-spacepropulsion systems, including nuclear-powered systems. In addition, NASA andthe U.S. Department of Energy will resume production of radioisotopethermo-electric generators, which provide power for deep space missions.

NASA also plans tosignificantly increase its spending on advanced launch vehicle technologies underthe Space Launch Initiative. Funded at $467 million in 2002, the Space LaunchInitiative would receive $769 million in 2003.

At the same time,however, NASA requested no funding to continue work on the X-38, a prototypecrew rescue vehicle for the international space station. The White Housedirected NASA to evaluate whether the Space Launch Initiative might yield aspace station crew rescue vehicle. The White House also directed NASA toevaluate non-U.S. options for performing the crew rescue mission.