Showing posts with label moon. Show all posts
Showing posts with label moon. Show all posts

Friday, December 30, 2011

Hackers plan space satellites to combat censorship

space satellite
Space Satellites
Computer hackers plan to take the internet beyond the reach of censors by putting their own communication satellites into orbit.

The scheme was outlined at the Chaos Communication Congress in Berlin.

The project's organisers said the Hackerspace Global Grid will also involve developing a grid of ground stations to track and communicate with the satellites.

Longer term they hope to help put an amateur astronaut on the moon.

Hobbyists have already put a few small satellites into orbit - usually only for brief periods of time - but tracking the devices has proved difficult for low-budget projects.

The hacker activist Nick Farr first put out calls for people to contribute to the project in August. He said that the increasing threat of internet censorship had motivated the project.

"The first goal is an uncensorable internet in space. Let's take the internet out of the control of terrestrial entities," Mr Farr said.

Beyond balloons

He cited the proposed Stop Online Piracy Act (Sopa) in the United States as an example of the kind of threat facing online freedom. If passed, the act would allow for some sites to be blocked on copyright grounds.

Whereas past space missions have almost all been the preserve of national agencies and large companies, amateur enthusiasts have in recent years sent a few payloads into orbit.

These devices have mostly been sent up using balloons and are tricky to pinpoint precisely from the ground.

According to Armin Bauer, a 26-year-old enthusiast from Stuttgart who is working on the Hackerspace Global Grid, this is largely due to lack of funding.

"Professionals can track satellites from ground stations, but usually they don't have to because, if you pay a large sum [to send the satellite up on a rocket], they put it in an exact place," Mr Bauer said.

In the long run, a wider hacker aerospace project aims to put an amateur astronaut onto the moon within the next 23 years.

"It is very ambitious so we said let's try something smaller first," Mr Bauer added.
Ground network

The Berlin conference was the latest meeting held by the Chaos Computer Club, a decades-old German hacker group that has proven influential not only for those interested in exploiting or improving computer security, but also for people who enjoy tinkering with hardware and software.

When Mr Farr called for contributions to Hackerspace, Mr Bauer and others decided to concentrate on the communications infrastructure aspect of the scheme.

He and his teammates are working on their part of the project together with Constellation, an existing German aerospace research initiative that mostly consists of interlinked student projects.

In the open-source spirit of Hackerspace, Mr Bauer and some friends came up with the idea of a distributed network of low-cost ground stations that can be bought or built by individuals.

Used together in a global network, these stations would be able to pinpoint satellites at any given time, while also making it easier and more reliable for fast-moving satellites to send data back to earth.

"It's kind of a reverse GPS," Mr Bauer said.

"GPS uses satellites to calculate where we are, and this tells us where the satellites are. We would use GPS co-ordinates but also improve on them by using fixed sites in precisely-known locations."

Mr Bauer said the team would have three prototype ground stations in place in the first half of 2012, and hoped to give away some working models at the next Chaos Communication Congress in a year's time.

They would also sell the devices on a non-profit basis.

"We're aiming for 100 euros (£84) per ground station. That is the amount people tell us they would be willing to spend," Mr Bauer added.


Experts say the satellite project is feasible, but could be restricted by technical limitations.

"Low earth orbit satellites such as have been launched by amateurs so far, do not stay in a single place but rather orbit, typically every 90 minutes," said Prof Alan Woodward from the computing department at the University of Surrey.

"That's not to say they can't be used for communications but obviously only for the relatively brief periods that they are in your view. It's difficult to see how such satellites could be used as a viable communications grid other than in bursts, even if there were a significant number in your constellation."

This problem could be avoided if the hackers managed to put their satellites into geostationary orbits above the equator. This would allow them to match the earth's movement and appear to be motionless when viewed from the ground. However, this would pose a different problem.

"It means that they are so far from earth that there is an appreciable delay on any signal, which can interfere with certain Internet applications," Prof Woodward said.

"There is also an interesting legal dimension in that outer space is not governed by the countries over which it floats. So, theoretically it could be a place for illegal communication to thrive. However, the corollary is that any country could take the law into their own hands and disable the satellites."
Need for knowledge

Apart from the ground station scheme, other aspects of the Hackerspace project that are being worked on include the development of new electronics that can survive in space, and the launch vehicles that can get them there in the first place.

According to Mr Farr, the "only motive" of the Hackerspace Global Grid is knowledge.

He said many participants are frustrated that no person has been sent past low Earth orbit since the Apollo 17 mission in 1972.

"This [hacker] community can put humanity back in space in a meaningful way," Farr said.

"The goal is to get back to where we were in the 1970s. Hackers find it offensive that we've had the technology since before many of us were born and we haven't gone back."

Asked whether some might see negative security implications in the idea of establishing a hacker presence in space, Farr said the only downside would be that "people might not be able to censor your internet".

"Hackers are about open information," Farr added. "We believe communication is a human right."

News by BBC

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Monday, December 12, 2011

Solar Storms Are "Sandblasting" the Moon, NASA Study Hints

solar storm
Solar Storm
The moon gets periodically "sandblasted" by intense solar storms that can strip tons of material from the lunar surface, a new NASA study suggests.

The sun is constantly emitting charged particles, or ions, in all directions in a stream called the solar wind. Scientists previously knew that solar ions can collide with and eject material on the moon's surface in a process dubbed sputtering.

But a new computer simulation finds that this sandblasting effect kicks into high gear during intense bursts of solar plasma—charged gas—known as coronal mass ejections (CMEs).

A strong CME can hurl about a billion tons of solar particles at up to a million miles (1.6 million kilometers) an hour in a cloud that is many times the size of Earth.

Normal solar wind is made up mostly of lightweight protons—hydrogen atoms that have been stripped of their electrons. But CMEs contain a much higher percentage of heavier ions such as helium, oxygen, and even iron.

These heavier atoms slam into the moon with greater force than protons, so they can dislodge a larger number of atoms from the surface.

"We found that when this massive cloud of plasma strikes the moon, it acts like a sandblaster and easily removes volatile material from the surface," study co-author William Farrell, leader of the Dynamic Response of the Environment At the Moon, or DREAM, team at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said in a statement.

"The model predicts 100 to 200 tons of lunar material—the equivalent of ten dump truck loads—could be stripped off the lunar surface during the typical two-day passage of a large CME."

Once ejected, about 90 percent of sputtered moon particles escape into space, where they become ionized and are drawn into the solar wind, said study co-author Rosemary Killen, also of NASA Goddard.

"The material is in atomic form," Killen added in an email to National Geographic News. "It is not meteoric and does not produce meteor showers" on Earth.

Sputtering Can Help Probe Moon's Chemistry?

CMEs are most likely to happen during solar maximum, a period of high magnetic activity on the sun that occurs about once every 11 years.

"The more active the sun, the more often coronal mass ejections take place," said Richard Elphic, a planetary scientist at the NASA Ames Research Center in California who was not involved in the study.

"You can have at the height of solar maximum a [large] CME maybe every week or so, and in some cases every few days. And that might be followed by a couple weeks of quiet."

Right now the sun is ramping up toward the next predicted solar maximum in 2013—which might aid research that uses sputtering to reveal clues about lunar chemistry.

A new moon orbiter scheduled to launch in 2013, called the Lunar Atmosphere And Dust Environment Explorer, or LADEE, could test the new model's predictions.

If the simulation is correct, then CME sputtering should loft lunar surface atoms to LADEE's orbital altitude, around 12 to 30 miles (20 to 50 kilometers).

"As the LADEE project scientist," Elphic said, "my excitement is in using these CME 'scavenging events' as active probes of the sputtering process, to learn what [types of atoms] are liberated and how long they stick around before equilibrium returns."

Moon Landing Footprints in No Danger

While the new model hints that the amount of lunar material stripped off by sputtering is more than scientists had thought, the amount of lost material is still very small compared to the total mass of the moon.

Also, the loss of lunar surface material is more or less balanced by incoming particles from micrometeorites, meteors, and the solar wind itself.

That means Earth's only natural satellite—and the features on it—are in no danger of being eroded away anytime soon. (Also see "The Moon Has Shrunk, and May Still Be Contracting.")

"The astronaut's footprints will still be there in recognizable form after a million years—if we're still around to see them," Elphic said.

News by Nationalgeographic

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