Aliens' hometown ?

This kind of information becomes almost regular in the space community, but this time it sounds better than ever > A life-friendly planet has been discovered and seems to host the most similar parameters to Earth than we ever know. Nearly 250 exoplanets (planets located outside our beloved Solar System) has been discovered until now, and this one will be the number one focus of scientists. What makes it so special ? (or so "familiar" ?) Let us give its ID :
- Name : Gl 581c (pretty sexy)
- location : Gliese 581 system (red dwarf)
- distance from Earth : 20.5 light years (peanuts)
- Mass : 5 times Earth's
- Diameter : 1.5 times Earth's (making it one of the smallest planet ever discovered)
- about the orbit : the orbit radius is 10.7 millions km with a period of 13 days. Earth is 150 millions km away from the Sun and has a 365 days period. The trick is that Gliese 581 (the exoplanet's sun) is far lighter and colder than the Sun, which makes our exoplanet being situated in the area where water can be liquid.
- consitution : as far as we know today, it is too much lighter to be made of gas. It is then a "rocky" planet, and further analysis will tell if it is an ocean planet, as some scientists guess.
Calculations show that if Gl 581c's albedo is 35% (as it is on Earth), average temperature would be 40°C. But if it is 50%, this temperature would decrease to the very nice value of 20°C, which would make the potential aliens not sweat.

This discovery is due to the great Franco-Swiss team leaded by Michel Mayor, already known for discovering the first exoplanet in 1995. They work on the French observatory located in La Silla, Chile,which hosts powerful instruments such as the VLT (Very Large Telescope) and its awesome adaptative optics system (that enables scientists to get rid of the atmospheric noise by a mirror system that compensates the atmospheric variations in real time).
The team placed the HARPS spectrometer (High Accuracy Radial velocity Planetary Search project - pfooo) on the 3.6m telescope. This instrument is well-known for being "the best exoplanet finder in the world", which is a label that few of us can claim.

The team did not mention yet if they have internet on Gl 581c, and we also don't know if the gravity constant can provide nice conditions for extreme skateboarding. We keep you informed.

StarTrek shielding

Most of the space agencies around the world announced lately their plans on human space exploration missions. But going to space is like a field trip to Chernobyl. Some protection is needed and neither sun cream or lead can provide a viable solution.
Scientists try to imitate Nature in the way it protects us from dangerous solar radiation or cosmic rays. They try to create an artificial magnetic field around the spacecraft which is strong enough to deflect all dangerous radiation.
The idea is not new. SS Enterprise from the Star Trek series was imagined to have such a deflector shield that the radiation would bounce off.

More on this...

hayabusa - typical japanese bad luck

Hayabusa - the Pilgrim Falcon - is a Japanese mission to collect sample material from a close to Earth asteroid. It was launched in May 2003 and arrived in a heliocentric orbit close to the Itokawa asteroid in September 2005. It managed to land on the surface of the asteroid, but the MINERVA mini-lander (~600 g) was lost due to the long command response time. It is not sure if the sample collection procedure was properly executed (a metal projectile should have hit the asteroid's surface) but it is supposed that at least a small quantity of dust will be found in the sealed container.
In December 2006, a fuel leakage determined loss of communication. It is supposed that 8 - 10 cc of leaked fuel evaporated resulting in a precession movement which stabilized into a spinning after 4 months. Communication was reestablished, but 4 out of the 11 battery cells were found to be damaged and that only 2 of the ion engines work normally.
At the beginning of April 2007, Hayabusa was expected to start it's journey home, a journey that will end in 2010.

More on Hayabusa's problems and solutions

was einstein right?

Gravity Probe B, a satellite launched by NASA in 2004 tested two of Einstein's General Relativity Theory predictions regarding gravity and space-time. "One is the geodetic effect-the amount by which the mass of the Earth warps the local space-time in which it resides. The other effect, called frame-dragging, is the amount by which the rotating Earth drags local space-time around with it. According to Einstein's theory, over the course of a year, the geodetic warping of Earth's local space-time causes the spin axes of each gyroscope to shift from its initial alignment by a minuscule angle of 6.606 arc-seconds (0.0018 degrees) in the plane of the spacecraft's orbit. Likewise, the twisting of Earth's local space-time causes the spin axis to shift by an even smaller angle of 0.039 arc-seconds (0.000011 degrees)-about the width of a human hair viewed from a quarter mile away-in the plane of the Earth's equator." (Spaceflight Now)

The experiment was conceived in the late '50s. It took more than 40 years to develop the technology that would run the otherwise simple experiment. After one year of collecting data, it took 18 months for extracting the necessary information for computing the geodetic effect. This proved to be in the range of 1% of Einstein's predictions. For the frame-dragging effect another 6 months are required for data processing. Models of electrostatic generated torques and sensor effects have to be carefully developed for reaching the required instruments' accuracy (4 inertial gyroscopes, a million times more precise than any other gyro ever built).

image credit: NASA

THEMIS satellites launching and deploying

Ever wonder how a satellite is launched and deployed? This is a short preview (now a review) of the launching and deploying of NASA THEMIS mission's 5 satellites. THEMIS is a mission to investigate auroras and magnetic substorms. 5 satellites were placed on highly elliptical orbits, the furthest stretching up to 216000 km. A Delta II three stage nine solid boosters rocket was used for the launch. Prior to deploying, the satellites are spin-stabilized at about 16 RPM. Each satellite has 4 hydrazine thrusters used both for attitude and orbit control. 6 booms (4x20m and 2x5m) are used for electrical field measurements and another one (2m) for magnetic field measurements.

The Hubble Deep Field: The Most Important Image Ever Taken

Hubble Ultra Deep Field is an image composed from 800 exposures taken in the course of 400 Earth orbits by HST (September, 2003 - January, 2004). It looks back in time 13 billion years, providing a new image on the origins of the universe.

best hubble photos

State of the Art in Digital Image Processing:

4. The Cat's Eye Nebula, one of the first planetary nebulae discovered, also has one of the most complex forms known to this kind of nebula. Eleven rings, or shells, of gas make up the Cat's Eye.

3. The Ant nebula is a cloud of gas and dust in the Milky Way Galaxy, 3000 - 6000 light years from Earth.

2. The "hood" around Eskimo nebula is a ring of comet-shaped objects flying away from a dying star.

1. Sombrero Galaxy: A brilliant white core is encircled by thick dust lanes in this spiral galaxy, seen edge-on. The galaxy is 50,000 light-years across, 800 billion suns and 28 million light years from Earth.

photos: hubblesite.org

don't put the battery in the sun!

A few months ago NASA lost contact with the Mars Global Surveyor orbiter. The mission was by far the most successful Red Planet focused mission: it took photos proving the existence of water on Mars; it surveyed the climatic changes for over 3 Mars years (the mission lasted four times longer than projected); it took the first photos of Earth viewed from Mars and of other two Mars orbiters (ESA's Mars Express and NASA's Mars Odyssey).

A NASA board investigated the communication failure which was tracked back to a loss of power. This is supposed to have been caused by a faulty orientation of the spacecraft which exposed one of the batteries to direct sunlight. The battery overheated and ultimately led to the depletion of both batteries. The funny thing about this is that the cause of the misplacement was traced back to a computer error made five months before the actual thing happened.

More on this subject...

photo credit: aritst view, NASA/JPL-Caltech

Tech details: From NASA's website: "The solar arrays, which always point toward the Sun (when the spacecraft isn't behind the planet), provide 980 watts of electricity for operating the electronic equipment and for charging nickel hydrogen batteries." Thermal blankets were used to protect sensitive parts. Nickel hydrogen batteries are used in many missions, including ISS and modern geostationary satellites. They have a current cycle life of 4000 to 10,000 cycles at 60 percent DOD, which doesn't recommend them for LEO (>30000 cycles). Provided power: >1kW, modern versions being expected to provide >6kW. The MGS batteries were based on 20 Ah 2-Cell common pressure vessel (CPV) technology.

why?

I would ask you "Why not?". We have a little bit of background (ok ok.. some of us more than a little bit). We need this information because information is power (hmm.. where did I hear this?). Nonetheless, as Samuel McChord Croters said: "The trouble with facts is that there are so many of them." Thus, we need to get them all together and filter whatever is not relevant/interesting. It's too much an effort for just one person, but we are many. And we come from a LOT of countries, i.e. more languages to cover. We also have a little bit of free time (yes, I am ironic). Plus, blogging is easy.

So.. Why not?