NASA’s Constellation program is asking agency headquarters for permission to cancel a long-planned Ares 1 test flight known as Ares 1-Y in order to pursue multiple earlier tests intended to speed introduction of the crew launch vehicle.

Originally planned for 2012, Ares 1-Y was to be a suborbital flight test of a five-segment booster with a flight production upper stage — minus its J-2X engine — and a functional Orion command module and launch abort system. After NASA modified its plans for Ares 1-Y late last year, the flight test slipped to the right. Constellation’s current manifest shows the Ares 1-Y flight test scheduled in March 2014.

Meeting two days after the successful Oct. 28 suborbital test flight of Ares 1-X — a four-segment booster with a dummy upper stage — Constellation program managers “decided that the Ares 1-Y flight fell too late in the vehicle development phase to provide useful information and lacks key elements to make it a true validation of the flight vehicle’s systems,” according to a Nov. 4 Constellation update posted on NASA’s official blog Web site.

“It simply does not fit where we are headed,” Constellation Program Manger Jeff Hanley said in the update. “The test vehicle was intended to meet evolving needs, but the current configuration is too different from what the program requires to certify the Ares/Orion vehicle systems.”

The Constellation program aims to conduct the crewed flight of Orion in 2015. A recently completed White House-ordered review of NASA’s human spaceflight program concluded Orion’s crewed debut would overshoot that target by at least two years and urged NASA to consider canceling Ares 1 and consider other options for putting astronauts into orbit.

In explaining the rationale behind canceling Ares 1-Y, NASA Constellation mangers said they “are also considering other options including a flight test that would fly in 2012 or 2013 that would have revised test objectives to better support vehicle development,” according to the Nov. 4 program update.