Science Briefs

International Space Station narrowly missed by space junk
Astronauts in the International Space Station took shelter in two docked spacecraft on March 24 as a piece of space junk passed dangerously close to the station. The debris, from the 2009 collision between an abandoned Russian satellite and an operational American one, passed the station without incident at a distance of 23 km.

There are at least 22,000 large (greater than 10 cm in diameter) objects in orbit around Earth. NASA estimates the population of smaller debris (between 1 and 10 cm) at about 500,000. At the high speeds at which objects in orbit travel, even a small piece of debris can do a lot of damage.

The International Space Station, the most heavily-shielded spacecraft ever flown, is capable of manoeuvring out of the way of debris, but only if it is detected far enough in advance. The threatening piece of debris was detected on March 23, which did not provide enough time to adjust the Space Station’s orbit.

This is the third time in 12 years that the ISS has been in danger from space junk. A closer call came in June 2011, when orbiting debris passed within 335 m of the station.

Genome sequencing . . . done cheap
Scientists have demonstrated a new method for sequencing DNA that could make the process relatively cheap and fast. A team led by Jens Gundlach of the University of Washington has implemented ideas, first posited in 1996, to read the chemical letters of a strand of DNA as it passes through a tiny pore.

“Nanopore sequencing,” as this technology is known, uses an electrical charge to drive a DNA strand through proteins with pores in them. The technology’s main obstacle was that the DNA travelled through the pore too quickly to be read properly. Scientists at the University of California, Santa Cruz, overcame this difficulty in 2010, when they suggested adding a protein called phi29 that would grip the strand of DNA, slowing its progress.

The Human Genome Project finished sequencing the human genome in 2003, at a cost of US $3 billion over 13 years. The technology has improved drastically since then, and in recent years the “$1,000 genome” has been a major goal of genomicists.

Gundlach’s team has published the first proof of concept for nanopore sequencing, but a corporate team claims to have already passed that milestone. In February, Oxford Nanopore Technologies announced that they could electrically read out DNA strands as they passed through a pore. They also claimed to be developing machines that run thousands of strands of DNA through nanopores in parallel. The machines would reduce the cost of sequencing a complete human genome to US $1,000 and compress the procedure’s length to 15 minutes.

“Oxford Nanopore was the first announcement, but they’ve been roundly criticized for not showing much data,” said Geoffrey Barrall, a scientist working on nanopore technology. “This is the first paper where somebody has actually sequenced DNA.”

Vatican pulls out of stem cell conference

The Vatican has cancelled the Third International Congress on Responsible Stem Cell Research, a controversial conference that Pope Benedict XVI was scheduled to attend in April. The event’s webpage cites “serious economic and logistic-organizational reasons” for the cancellation.

The program was set to include Alan Trounson, president of the California Institute for Regenerative Medicine, and George Daley, a researcher at the Children’s Hospital Boston in Massachusetts, as speakers. Both scientists are involved in human embryonic stem cell research, which the Vatican opposes on ethical grounds, leading to speculation that the event was cancelled because of their involvement.

An anonymous member of the Pontifical Academy for Life, which organized the event, was relieved by the cancellation, saying that the presence of embryonic stem cell researchers was “a betrayal of the mission of the Academy and a public scandal.” According to an article published in Nature several European scientists declined invitations to speak at the conference, saying that it was not an open discussion and they would be portrayed as “bad guys.”

A spokesperson for the Pontifical Academy for Life said that he cannot speak until an official explanation is released. He called the cancellation a “sad event” and noted that until March 23, the plan was to go ahead with the event.