A Japanese space probe plagued by technical problems has made its final flyby of the Earth and is on its way to Mars, space program officials said Friday. The probe, named Nozomi, which means Hope, passed within 6,800 miles of the Earth in a manuever designed to use the planet’s gravity to slingshot the probe toward Mars. Mission planners would not be able to determine whether the flyby, conducted just before midnight Thursday, was a success for about another week, according to a statement by the Institute of Space and Astronautical Science.