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NEWSBITS
Internet beams out into space
Nasa’s spacecraft and satellites could soon have their own net address.
The space agency is working on a project to make it easier to retrieve data from spacecraft and satellites in orbit or deep space and is turning to net data protocols to help.
The project will allow mission scientists to use a standard web browser to monitor spacecraft and to swap data with them or their crew.
The technology to link spacecraft to the web is being tested on the current space shuttle mission and briefly turned the Columbia craft into a node on the net.
Nasa is keen to use standard terrestrial techniques to route data to and from satellites and spacecraft to cut costs and make off-planet resources easier to manage.
The space agency currently uses a mish-mash of ageing hardware and software to keep in touch with spacecraft and to ship data back and forth.
By converting to tried and tested technologies used to keep the net running, Nasa believes it can cut the numbers of staff needed to ensure spacecraft stay in touch.
To test the technology the Columbia space shuttle was fitted with an embedded PC that has a 233 MHz processor, 128 MB of RAM and a solid-state 144 MB hard drive.
The computer is running Red Hat, a version of the Linux operating system, and is maintaining a connection with the Goddard Space Flight Center which will to try to contact the onboard PC more than 140 times over the duration of the shuttle mission STS-107.
Maintaining contact with orbiting spacecraft presents its own problems.
One of the main problems to deal with is the fact that the shuttle is constantly moving and as a result must regularly change the route used to contact the terrestrial network.
Nasa scientists behind the Omni project (Operating Missions as a Node on the Internet) have developed a way for the shuttle to hand its communication needs to different satellites and ground stations as it travels.
In effect the craft stays in constant touch with its handlers at the Goddard Space Flight Centre in Washington even when it is on the other side of the world. Once fully developed the net-based communication system will give astronauts and hardware aboard the shuttle much more freedom to communicate with the Earth.
Data sent to and from space also needs improved error correction to ensure that it is not scrambled or corrupted by the extremes of radiation present in space.
The current shuttle mission is due to end on 1 February. The technology to turn spacecraft into net nodes was first tested in late May 2000 on the UoSat-12 mission.
The world’s first orbiting web address travelled on this small satellite which was developed by Nasa and Surrey Satellite technology. — Dawn ScienceDotcom Report
Fossil find stirs human debate
The fossil of an early human (hominid) from southern Africa is raising fresh questions about our origins.
Remains from the Sterkfontein Caves near Johannesburg suggest our ancestors were less chimp-like than we thought.
The revelation follows the discovery of missing bones from a 3.5 million-year-old skeleton found in 1998.
Fragments of pelvis, upper leg, ribs and backbone have recently been dug out of the rock, allowing scientists to piece together its gait.
The anatomy of the hominid, a member of the genus Australopithecus, raises some interesting questions.
Its bone structure shows it did not walk like modern chimps, using the knuckles of its hands.
It probably walked on two legs when it was on the ground but spent much of the time climbing trees, says Dr Ron Clarke, of the University of the Witwatersrand, who discovered the fossil.
Tool-making
Dr Clarke goes further. He argues that the fact the hominid was not a knuckle-walker suggests chimps and humans are not as closely related as we thought.
It pushes the last common ancestor of chimps and humans much further back in history, he says.
Dr Clarke sets out his position in the South African Journal of Science, which publishes the latest data.
“My conclusion from the limb proportions and the morphology of the foot and of the hand is that this Sterkfontein individual was a climber in the trees (using its powerful thumb in a vice-like grip) and bipedal on the ground,” he says.
“It would appear, therefore, that the strong opposable thumb evolved in the human ancestral stock for grasping branches. Then, in the mainly terrestrial subsequent descendants in the form of Homo, it was to prove useful for tool-making and manipulation.
“The suggestion in reconstructions and in the scientific literature that human ancestors were transformed into an upright position from a knuckle-walking ancestor is not supported by this new and important addition to the fossil record.”
Other experts in human evolution are more circumspect. Professor Chris Stringer of London’s Natural History Museum says the idea that humans and chimps derive from a knuckle-walking common ancestor is “not a majority view”.
The peculiar gait of chimps and gorillas could have developed after the three lines diverged, he says.
Dr Robin Crompton of the University of Liverpool agrees. He says there is “very strong” genetic evidence that we are closely related to chimps (and bonobos).
“It is likely that the common ancestor of the African apes, including ourselves, was arboreal,” he said.
“In my view, knuckle-walking and vertical climbing - up and down tree trunks - are a specialisation of chimps and gorillas after humans split off from them.”
Sterkfontein is probably the richest site on Earth for the fossils of early humans (hominids), and the ancient cave system is now part of a World Heritage Site.
Some 600 hominid fossils from the Sterkfontein Caves have now been collected and classified.
The early humans they represent are thought to have fallen to their deaths in the caves when the limestone complex first broke the surface. — Dawn ScienceDotcom Report
Was the mission doomed at the start?
NASA engineers are taking a second, harder look at video, computer data and everything else that led them to conclude — perhaps wrongly — that a flyaway chunk of insulation did not harm space shuttle Columbia during lif-toff.
“We are completely redoing the analysis from scratch,” shuttle program manager Ron Dittemore said Monday, exactly one week after engineers assured him that any damage to the shuttle’s thermal tiles was minimal. “We want to know if we made any erroneous assumptions.”
Practically from the start, investigators have zeroed in on a piece of foam insulation that fell off the shuttle’s big external fuel tank during lift-off Jan 16. The impact by the 20-inch fragment may have damaged the heat tiles that keep the ship from burning up during re-entry into the atmosphere. “We’re making the assumption from the start that the external tank was the root cause of the problem that lost Columbia,” Dittemore said.
The half-page engineering report — issued on Day 12 of the 16-day flight — indicated “the potential for a large damage area to the tile.” But the analyses showed “no burn-through and no safety-of-flight issue,” the report concluded.
No one on the team had any reservations about the conclusions and no one reported any concerns to a NASA hotline set up for just such occasions.
“Now I am aware, here two days later, that there have been some reservations expressed by certain individuals and it goes back in time,” Dittemore said. “So we’re reviewing those reservations again as part of our data base. They weren’t part of our playbook at the time because they didn’t surface. They didn’t come forward.”
Readdy said the damage done by the broken-off piece of insulation is now being looked at very carefully as a possible cause of the tragedy. The shuttle, covered with more than 20,000 thermal tiles, broke up 39 miles over Texas and fell to Earth just as it was experiencing maximum re-entry heat of 3,000 degrees.
NASA said temperature data showed that the shuttle’s left side — the same side hit by the debris — heated up sharply just before Columbia disintegrated.
The foam that covers the shuttle’s 154-foot external fuel tank is hard enough to damage the shuttle when the spaceship is hurtling into space at high speed.
Dittemore said he knows of at least two other shuttle launches in which foam came off and damaged the shuttle, though nowhere near to the extent suspected in the case of Columbia. One of the shuttles — Columbia, in 1992 — had tile damage on the wing.
Engineers relied heavily on the fact that the previous damage was so minor. — Dawn ScienceDotcom Report
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