NASA engineers studied two potential technical problems on Wednesday that could influence the scheduled launch of the space shuttle Discovery, even as the countdown for the Thursday blast-off continues.
The shuttle is scheduled for a 12-day mission to the International Space Station as NASA races to finish building the station before it retires its three-shuttle fleet in 2010.
The countdown for a lift-off at 2135 EST on Thursday (0235 GMT Friday) continued, said LeRoy Cain, launch integration manager of the shuttle programme.
If all goes as planned, it will be the first night launch since the space shuttle Endeavour lifted off on 23 November 2002.
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However, late on Tuesday engineers saw a voltage increase during routine preparations. “We think it may have been a faulty potentiometer, one of the sensors that are used to monitor the system when we do those power adjustments,” he said.
The second problem was an anomaly in the solid rocket booster motor joint detected during testing. “We need to look further and determine if we have any concern,” Cain said of that problem. “I don’t want to speculate yet.”
Forecast worsens
He said the issue would be discussed on Wednesday in meetings with the shuttle mission management team.
Meanwhile, the weather forecast has worsened from a 70% chance of acceptable launch weather on Thursday to just a 40% chance of good weather due to low clouds in the area. A launch on Friday has just a 30% chance of good weather, while the outlook for Saturday improves slightly to a 40% of acceptable conditions.
The space agency has set a window for rescheduling the lift-off that lasts until December 17.
Discovery’s mission to rewire the orbiting ISS in two space walks is its most complex to date. The astronauts will also bring an $11 million truss segment to be added to the orbiting laboratory in a third walk.
The seven-member Discovery crew will include Swedish astronaut Christer Fuglesang of the European Space Agency, who will be making his first space flight.
Station completion
The US space agency plans 14 shuttle missions, including Thursday’s, to finish building the ISS by 2010.
Thursday’s lift-off will be the third and final shuttle launch of the year, and the fourth since the Columbia disaster in February 2003 that killed seven astronauts, grounding the shuttle programme for more than two years.
The three launches after the Columbia tragedy – in August 2005, and July and September 2006 – were scheduled during daylight so that cameras on the ground and on the shuttle could take images of the spacecraft’s exterior tank in case pieces of thermal insulation or ice might break off during lift-off.
A piece of insulating foam damaged Columbia’s heat-shield shortly after launch, leading to the shuttle disintegrating upon re-entry to Earth’s atmosphere.
The September launch marked the resumption of ISS construction, after the previous two missions focused on improving safety.
![Astronomers have long known that understanding how star clusters come to be is key to unlocking other secrets of galactic evolution. Stars form in clusters, created when clouds of gas collapse under gravity. As more and more stars are born in a collapsing cloud, strong stellar winds, harsh ultraviolet radiation and the supernova explosions of massive stars eventually disperse the cloud, and their light can bear down on other star-forming regions in the galaxy. This process is called stellar feedback, and it means that most of the gas in a galaxy never gets used for star formation. Researching how star clusters develop can answer questions about star formation at a galactic scale. Now, the state of the art has been further developed with both Hubble and Webb working together to provide a broad-spectrum view of thousands of young star clusters. An international team of astronomers has pored over images of four nearby galaxies from the FEAST observing programme (#1783), trying to solve this mystery. Their results show that it is the most massive star clusters that clear away their gaseous shroud the fastest, and begin lighting their galaxy the earliest. The team identified nearly 9000 star clusters in the four galaxies in different evolutionary stages: young clusters just starting to emerge from their natal clouds of gas, clusters that had partially dispersed the gas (both from Webb images), and fully unobstructed clusters visible in optical light (found in Hubble images). With Webb???s ability to peer inside the gas clouds, they were able to then estimate the mass and age of each cluster from its light spectrum. This image shows a section of one of the spiral arms of Messier 51 (M51), one of the four galaxies studied in this work, as seen by Webb???s Near-Infrared Camera (NIRCam). The thick clumps of star-forming gas are shown here in red and orange, representing infrared light emitted by ionised gas, dust grains, and complex molecules such as polycyclic aromatic hydrocarbons (PAHs). Within these gas complexes, each tens or hundreds of light years across, Webb reveals the dense, extremely bright clusters of massive stars that have just recently formed. The countless stars strewn across the arm of the galaxy, many of which would be invisible to our eyes behind layers of dust, are also laid bare in infrared light. [Image description: A large, long portion of one of the spiral arms in galaxy M51. Red-orange, clumpy filaments of gas and dust that stretch in a chain from left to right comprise the arm. Shining cyan bubbles light up parts of the gas clouds from within, and gaps expose bright star clusters in these bubbles as glowing white dots. The whole image is dotted with small stars. A faint blue glow around the arm colours the otherwise dark background.]](https://images.newscientist.com/wp-content/uploads/2026/05/13114322/SEI_296271016.jpg)
