NEW YORK — With the next shuttle launch delayed, astronauts living aboard the international space station (ISS) are filling the time gap with extra scientific research and maintenance work originally scheduled to be conducted by the next crew.

ISS Expedition 14 commander Michael Lopez-Alegria and flight engineers Mikhail Tyurin and Sunita Williams have squeezed in more time to perform human physiology experiments and help set up part of a new station computer network.

NASA delayed the launch of the STS-117 mission in late February, pushing the ISS assembly mission to late April at the earliest after a severe storm battered the shuttle Atlantis’ external fuel tank with golf-ball-sized hail. That delay and a one-month mission extension of the planned launch of the new crew set to replace Lopez-Alegria and Tyurin, who is called Misha by his colleagues, have made room for the additional activities, ISS mission managers said.

“We’re a little bit bummed out about the fact that STS-117 is not going to be up here when [Lopez-Alegria] and Misha are going to be here,” Williams told her mother Bonnie Pandya during a recent radio interview. “But that will be OK.”

Squeezing in Science

The Expedition 14 astronauts have spent the bulk of their extra science time on two experiments, dubbed ALTEA (Anomalous Long Term Effects in Astronauts’ Central Nervous System) and TRAC (Test of Reaction and Adaptation Capabilities), each aimed at better understanding how the human body adapts to long-duration spaceflight.

“When we started our planning for the increment, we knew … that in the time frame between the last shuttle flight and the end of the increment, we were going to have very little time for [science] utilization,” Melissa Owens, said NASA’s ISS Expedition 14 increment manager. “And we had kind of warned the utilization community [scientists] you know, ‘ look, this is a really intensive ISS assembly sequence and we’re just not going to have enough time.’”

Lopez-Alegria was not trained to perform the ALTEA experiment, which uses a sensor-laden helmet to measure the effects of cosmic radiation on an astronaut’s central nervous and visual systems. But he has since donned the ALTEA cap and performed several runs to the delight of researchers on Earth, Owens said.

“It’s essentially trying to determine what part of your brain is detecting light flashes, which is a common occurrence up here in space,” Williams said.

All three of the Expedition 14 crewmembers also have managed to participate in the TRAC experiment, which tests eye-hand coordination to study how the human brain adapts to the spaceflight environment.

At least five sessions per astronaut, unattainable during the Expedition 14 crew’s previous schedule, were required to generate usable data. Lopez-Alegria, Tyurin and Williams are now expected to meet that goal, Owens said.

“To some extent, it’s been a silver lining because it’s given us time to do some utilization,” Owens said, adding that the Expedition 14 astronauts still have some extra time in the next couple of weeks to perform science or tasks slated for their Expedition 15 successors. “We’re still talking with them to ask, ‘ are there any additional tasks that we can move forward to help you?’” she said.

Williams said she and her crewmates have spent some weekend free time performing experiment trials with the station’s bowling ball-sized Synchronized Position Hold Engage Re-orient Experimental Satellites , to test autonomous spaceflight systems, among other research.

“There’re a bunch of things that we’re working on up here as well as construction of the space station,” she added.

When they’re not performing extra science work, the Expedition 14 crew also has accelerated their work schedule and — at times — performed a few chores originally scheduled to be conducted by their Expedition 15 successors.

One fairly work-intensive activity originally scheduled for Expedition 15 included routing a data cable through the station’s hub-like Unity node, threading it behind module panels to form part what will eventually be a station-wide computer network 10 times faster than the current version, NASA officials said.

“It’s a new network that we’re trying to build so that eventually all of the computers on the station will work on one network,” Owens said, adding that when complete, the system will allow Russian ISS systems to be controlled from the outpost’s U.S. Destiny laboratory, a capability unavailable today.

The Expedition 14 astronauts also have installed a new Unity hatch window and primed a conical ISS connecting segment, known as Pressurized Mating Adapter-3 , for its eventual relocation from its perch on the outpost’s Unity node. The connector is due to be moved prior to NASA’s planned STS-120 mission this summer, which is expected to install a new hub module, the newly named Harmony node, to the Pressurized Mating Adapter-3’s current berth.

The crew’s next major hurdle will come March 29, when all three astronauts are expected to don their Russian-built Sokol spacesuits and move their Soyuz TMA-9 spacecraft from its Earth-facing Zarya module docking port to a parking spot at the aft end the station’s Zvezda service module.

The short flight, an unusual second Soyuz relocation for the ISS crew, will allow the Expedition 15 crew to dock at the Zarya port directly and avoid a tightly packed relocation of their own spacecraft near the planned STS-117 mission to the ISS, Owens said.

“It’s gone really well, the crew has been happy, they’ve consistently commented that we’ve struck a really good balance between keeping their days full and not wearing them out,” Owens said. “They’ve really been on top of it.”