Space debris: Expert warns of increasing CubeSat collision risk

A Clyde-Space CubeSat in the Scottish test lab.

Credit: Clyde-Space

The increasing number of small 'CubeSat' satellites being launched combined with a relaxed attitude to debris mitigation could lead to hazards for all space users unless preventative measures are taken, warns a leading space debris expert from the University of Southampton.

Speaking today at the 65th International Astronautical Congress (IAC) 2014 in Toronto, Dr Hugh Lewis said that this combination leads to a growth in space debris, as a result of collisions between CubeSats and other objects in orbit.

CubeSats are small satellites (around 10x10x10cm) that are providing opportunities for companies to break into the space data and communications industries.

Despite many CubeSats not having any manoeuvring capability so they cannot avoid collisions during the mission or manoeuvre to a disposal orbit at their mission end, they are still perceived to have a low impact on the space debris environment.

However, despite guidelines requiring the satellites to deorbit within 25 years, some are being launched into high Earth orbits, which means their orbital lifetime could be much greater.

More than a third of all CubeSats launched to-date (around 160 between 2003 and 2013) are predicted to remain on-orbit for more than 25 years.

Since 2005, CubeSats have been involved in more than 360,000 close approaches of less than 5 km with other orbiting objects.

Dr Lewis says: "To reduce the risks, some effort is needed to engage with the growing small satellite community."

"All space users, not just those in the CubeSat community, who are taking the right steps should be encouraged to continue and, ultimately, lead on sustainable practices and debris mitigation activities.

"Those who are not yet engaged with this approach should be encouraged to do so. It's probably a matter of changing their perceptions of the risks and helping them to understand that there is a collective responsibility to ensure that outer space activities are sustainable so that future generations have the same opportunities to use space as we do."

Dr Lewis and his team used their Debris Analysis and Monitoring Architecture to the Geosynchronous Environment (DAMAGE) model to simulate three future CubeSat launch traffic scenarios until the year 2043.

By comparing these with close approach data from 2005 to 2013, the team found CubeSats are estimated to be involved in millions of close approaches over the next 30 years, with a handful leading to a collision.

Analysis of the close approaches found that most of the collision risk from CubeSats comes from high-speed encounters with large spacecraft.

In addition, many of these encounters were in Sun-synchronous orbits that are popular with remote sensing and Earth science satellites.

Dr Lewis adds: "By far the greatest risk comes from those with long lifetimes at altitudes of about 750 km. If CubeSats continue to be launched into long-lived orbits without any means of disposing of them, then they will contribute to the growing space debris hazard."

"This is not a responsible or sustainable practice, in my view. However, if efforts are made to limit the lifetimes, as some are already doing, then the risks will be reduced."

Geologists warning of mega Earthquake for Iquique North Chile

North Chile is at risk of a mega earthquake after a tremor in April released only some of the tension building along a high-risk fault zone since 1877, researchers said Wednesday.

Two studies published in the journal Nature said the 8.1-8.2 magnitude quake that shook the city of Iquique, killing six people and forcing a million to leave their homes, may not have been the anticipated Big One.

Scientists have long kept an eye on the north Chile subduction zone, where a slab of the Earth's crust is driving under the South American continent at an average rate of about seven centimetres per year.

Subduction zones are known for yielding powerful quakes.

In 1877, a tremor with an exponentially much higher 8.6-8.8 magnitude ruptured nearly 500 kilometres of the north Chilean fault.

The April 1 Iquique rattler, followed by a strong aftershock, broke only a section of the so-called seismic gap; a section of an active fault that had not ruptured in a long time, building up stress to be released as a major quake.

Gavin Hayes

"Our results... indicate that this (Iquique) was not the earthquake that had been anticipated," wrote the authors of the first study led by Gavin Hayes of the United States Geological Survey.

The study "Continuing Megathrust Earthquake potential in Chile after the Iquique Earthquake" is published in the journal Nature.

"Significant sections of the northern Chile subduction zone have not ruptured in almost 150 years, so it is likely that future megathrust earthquakes will occur to the south and potentially to the north of the 2014 Iquique sequence."

Megathrust earthquakes are often followed by killer tsunamis.

"Observations suggest that enough strain has accumulated along this plate boundary segment to host an earthquake close to M9 (magnitude 9)," the team cautioned.

The authors of the second study said the Iquique quake broke about a third of the northern Chile seismic gap, and agreed that "the remaining locked segments now pose a significant increased seismic hazard."

They put the potential magnitude of such a quake at 8.5.

The second study "Gradual unlocking of plate boundary controlled initiation of the 2014 Iquique earthquake" is also available in the journal Nature.

The corresponding author of this study is Bernd Schurr of GFZ Potsdam.

"The Big One may still be to come," added University of California geologist Roland Burgmann, who wrote a comment on the studies.

Hayes and his team said that on the basis of their findings, "Chilean and global seismologists now face the difficult task of communicating this uncertain yet perhaps elevated hazard, without appearing alarmist."

Chile is one of the most seismically active countries in the world.

Boeing 787 dreamliner: 15 airlines warned over high-altitude ice on GE engines

Boeing plans to raise production of the 787 Dreamliner to 12 per month by 2016

Fifteen airlines have been warned about the risk of ice forming on Boeing's new 747-8 and 787 Dreamliner planes.

The issue - affecting some types of engines made by General Electric when planes fly near high-level thunderstorms - prompted Japan Airlines to cancel two international routes.

There have been six incidents since April when aircraft powered by GE engines lost power at high altitude.

These are the latest technical issues to hit the Dreamliner.

They saw the entire fleet being grounded earlier this year following battery problems.

The Boeing 747-8 series and the new 787 Dreamliner and the only types of aircraft affected by the high-altitude icing issue.

The new warning was given to airlines including Lufthansa, United Airlines and Japan Airlines.

It says aircraft with the affected engines - GE's GEnx - must not be flown within 50 nautical miles of thunderstorms that may contain ice crystals.

As a result, Japan Airlines (JAL) has decided to withdraw Dreamliners from service on the Tokyo-Delhi and Tokyo-Singapore routes.

"Boeing and JAL share a commitment to the safety of passengers and crews on board our airplanes."

"We respect JAL's decision to suspend some 787 services on specific routes," a Boeing spokesman said, according to Reuters news agency.

A GE spokesman told the agency the aviation industry was experiencing "a growing number of ice-crystal icing encounters in recent years as the population of large commercial airliners has grown, particularly in tropical regions of the world".

He said GE and Boeing were hoping to eliminate the problem by modifying the engine control system software.

British airways use Rolls Royce engines on their Dreamliners and are not affected by the warning.

Space Debris: Ecuador Pegaso satellite collides with Russian rocket remains

An Ecuadoran satellite launched last month, with the help of China, has collided with the remains of a Russian rocket in the coming hours, the country's civilian space agency warned Wednesday.

The "Pegaso" (Pegasus) nanosatellite, designed and built in Ecuador, set off aboard an unmanned rocket April 25 from the Jiuquand station in northern China. It is the country's first.

The Joint Space Operations Center in the United States, which monitors all artificial Earth-orbiting objects, said there had been no head-on crash but "data indicated a lateral collision with particles" of the Soviet-era rocket.

"Pegasus could be damaged or spinning out of control but, because it's still in orbit, we have hope," Ronnie Nader, head of the Ecuadorian Civilian Space Agency, tweeted.

"Ecuador still has its satellite, the people still have Pegasus," he wrote, saying it could take up to 48 hours to assess damage.

The 2.6-pound nanosatellite had been orbiting at a distance of 404 miles while transmitting pictures of the Earth.

Measuring just 10 by 10 by 75 centimeters (four by four by 30 inches), and weighing 1.2 kilograms (2.6 pounds), Pegaso on Thursday transmitted its first live video with audio.

Last month's launch came amid much fanfare, including a live broadcast.

The South American country plans to send a second satellite into space from Russia in July.