Shuttle blasts into orbit on third try
The seven astronauts aboard are scheduled to meet up with the International Space Station on Thursday. They will deliver supplies and conduct repairs during their 12-day flight.
This is NASA's first space shuttle launch on Independence Day and only the second launch since the Columbia disaster in 2003.
"For all the folks in the Florida east coast, we hope to very soon get you an up-close-and-personal look at the rocket's red glare," Discovery commander Steve Lindsey said from the launch pad before launch.
Discovery launched at 1438 EDT (1838 GMT) and reached orbit 8 minutes and 40 seconds later. Weather was remarkably well behaved on Tuesday after two weather-related launch delays over the weekend (see Shuttle launch postponed again). Ultimately, the clouds and storms stayed clear at launch time.
Camera views
Image analysts are now poring over video and still pictures to see how much foam insulation came off the external fuel tank during launch. They will also be checking to see whether any of those pieces struck the orbiter, which is what happened during Columbia's launch three years ago.
During Discovery's last launch in July 2005, these new camera views showed several pieces of foam shedding from the tank. The biggest piece was 0.4 kilograms (1 pound). NASA does not expect to see any pieces that large this time because they removed the protuberance air load (PAL) ramp, the part that shed the largest foam chunk last year.
NASA is scheduled to hold a briefing later today to give reporters its initial interpretation of some of the camera views.
Discovery is scheduled to stay in space for 12 days with a landing on 16 July, but the mission could be extended for several days to either embark on a third spacewalk or to allow time for weather to clear at the shuttle's three possible landing sites in Florida, California and New Mexico, US.
Last-minute glitches
The mission is significant because it will deliver European Space Agency astronaut Thomas Reiter to the ISS, boosting the station crew to three. The crew was downsized to two after the Columbia accident because the shuttles were grounded and could not deliver enough supplies to support three people.
Commander Steve Lindsey, pilot Mark Kelly and astronauts Mike Fossum, Piers Sellers, Lisa Nowak and Stephanie Wilson round out Discovery's crew.
As is fairly common for shuttle launches, last-minute technical glitches threatened to delay liftoff. On Saturday morning, the shuttle faced a problem with a heater on one of its in-space thrusters, designated L5L. The thruster's thermostat was not working, but mission managers determined they could fly the shuttle without that heater.
Then after Sunday's launch attempt, an inspection team on the launch pad found foam that had fallen off the external tank. Engineers believe that the foam came off because rainwater froze near a bracket on the tank and then melted when the cryogenic fuel in the tank was drained. The bracket helps to keep a liquid oxygen feedline – which funnels cryogenic oxygen into the tank – in place.
NASA's Mission Management Team decided that the missing foam would not cause a dangerous amount of ice to form in that region from condensation in the humid air (see Shuttle to lift off despite foam loss).
Discovery: Why mosquitoes dont like some people, but love others.
Some unfortunate people are irresistible to mosquitoes, while the scent of some lucky individuals drives the blood-suckers away. Now the smelly chemicals from the sweat of these lucky people have been identified by researchers, who are testing its effectiveness as a natural mosquito repellent.
Everybody produces a mixture of odorous chemicals in their sweat, some of which attract biting insects, such as lactic acid. But people who do not get bitten also produce smelly chemicals that appear to mask the scent of the attractive chemicals.
This masking can offer an effective camouflage against mosquitoes, explains James Logan, who carried out the research with John Pickett at Rothamsted Research in Harpenden, and colleagues at the University of Aberdeen, both in the UK.
These helpful chemicals probably occur naturally in everybody’s sweat but some people have a much higher ratio than others, Logan says.
What is more, the same benign sweat chemicals that repel the tropical mosquitoes Aedes aegypti – responsible for spreading yellow fever throughout Africa and South America – appear also to disgust the persistent biting midge that terrorises the west coast of Scotland, the researchers discovered.
Sweat collectors
Logan constructed a Y-shaped chamber and wafted the scent of different people down two of the branches by getting volunteers to place their hands at the ends. The blood-sucking insects flew from the thin end of the "Y" towards the human hand they preferred.
He then analysed the body odour of those individuals found to be unattractive by sealing their bodies in a foil sack, tied under the chin, and collecting and distilling the sweat that poured off them.
The most potent repellent chemical were then isolated by strapping miniature electrodes to the antennae of female mosquitoes and checking their responses to specific compounds. Logan will not divulge the names of the chemicals until they are patented. But he does reveal that although the scent of the chemicals is normally undetectable by humans, they have a fruity smell when highly concentrated.
Food additive
“It’s very exciting," Logan told New Scientist, "because these are totally natural chemicals with an effectiveness that compares favourably to harsher chemicals such as DEET, which is the best repellent available but has unwanted effects, including dissolving plastics.”
A key chemical identified by Logan as a repellent is also "a natural food additive, so has proven safety", he says. "And because it can be made by plants, it may one day be possible to mass produce it cheaply.”
The repellent is currently being trialled with 16 volunteers in Africa. Meanwhile, the researchers are testing the repellent against other biting insects, including malaria carrying mosquitoes.
The research was presented at the Royal Society Summer Science Exhibition in London, UK, and has been submitted to a leading peer review journal for publication.
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