Tag Archives: NASA

Laser to zap space garbage

To get you started thinking about space junk:

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NASA space scientist James Mason and his team of NASA Ames Research Center and  the University of Space Research Association in California have recently proposed a new theory to deal with the pieces of debris in the low Earth orbit (LEO) that are colliding with each other to create more pieces. They discovered a possible method of using a laser beam to change the velocity of the junk’s orbit by focusing the beam on it to slow it down and change its orbit. This can stop the debris from colliding with communications satellites or the International Space Station.

Satellites and space junk in orbit around Earth CREDIT: ESA

The scientists mention that continual evaluation of the chances of a collision between two space debris of 5 cm or more in diameter would be needed using radar data from the US Space Surveillance Network. The junks on the path of collision would then be tracked by an optical telescope. One of them will be locked on and the release of the laser beam will occur. Just by using 5-10 kilowatts commercially available lasers mounted on 1.5 meter telescopes placed close to the poles, the risk of more than half of potential space junk collisions could be significantly reduced. The total cost of the scheme would be no more than $10m, making it a much cheaper alternative than other ideas such as direct removal of space debris.

The new paper could give insight into how we can avoid the Kessler syndrome, where if more and more space junk are be created and colliding with each other, the generations of debris could ultimately render space exploration and satellite launches impossible. This prediction was done by a NASA scientist in 1978 and new solutions have been presented since then a lot with multiple complications and high price tags. Moreover, other countries involved in space exploration saw the proposed methods as threats to their functional satellites.

Although a feasible theory, the scientists speculate whether this method could actually do the trick remains a topic of debate. Team member William Marshall points out that there are a lot of uncertainties in the model and space-debris models need to be run to be certain that the theory will be effective in the long term.

NASA probe MESSENGER is first to enter Mercury’s orbit

Humanity has just reached another milestone in space exploration. Yesterday, on March 17, NASA’s MESSENGER probe entered orbit around Mercury becoming the first spacecraft to ever do so.

MESSENGER probe approaching orbit around Mercury

MESSENGER (actually short for Mercury Surface, Space Environment, Geochemistry and Ranging) was launched almost 7 years ago in August of 2004. It was designed to examine the magnetic field around mercury, as well as chemical composition and geology of the surface.

Since then, MESSENGER has made three flybys past Mercury and has made some interesting discoveries that have puzzled scientists for years.

Evidence of Volcanic activity on the surface of Mercury

Back in July of 2008, MESSENGER made the startling discovery of water present in Mercury’s exosphere (the uppermost later of the atmosphere). It also found evidence of extensive volcanic activity on Mercury’s surface. Previously, scientists believed that the volcanic gases would have long ago exited Mercury or had been absent at its formation.

MESSENGER’s new mission will have it begin to throughly examine the surface for the chemical signatures of these gases with an array of seven instruments (set to be activated on March 24). The probe will also study the presence of water on Mercury and also examine the planet’s core.

MESSENGER's gravity assist maneuvers

What made MESSENGER’s voyage to Mercury interesting were some of the challenges that scientists had to overcome. Normally, a probe approaching the planet would become too accelerated due to the force of the Sun’s gravity and fly past the planet before it could maintain orbit. MESSENGER had to overcome this by using a series of gravity assist maneuvers to slow it down. These maneuvers utilize the gravity of a planet to change the path of the spacecraft. If you’ve ever seen the movie “Armageddon”, this was like the scene where the spaceship did the “roadrunner thrust move” around the Moon. MESSENGER had to utilize the gravity from Mercury, Venus and Earth to perfect its trajectory to orbit the planet.

What’s truly remarkable is that these series of gravity assisted moves mean that MESSENGER has traveled 7.9 billion kilometers through space since 2004.

The other challenge for scientists was thermal damage due to Mercury’s high surface temperatures. They solved this by making MESSENGER have a highly elliptical orbit around the planet. The trajectory takes the probe within 200 km of the surface then 15,000 km away, presumably when the temperatures are hottest. One of these cycles takes 12 hours.

The probe’s first set of measurements are scheduled to be sent to Earth on April 4. Who knows what’s waiting to be discovered beneath the surface of Mercury!

The original article can be found here.

Mercury – NASA’s Fifth Planetary Conquest

Image of Mercury from previous Messenger missions. From NASA.

After years of planning and development, NASA’s space probe Messenger finally fell into Mercury’s orbit Thursday evening. At 9:10 p.m. of March 17, when the last rocket that projected Messenger shut off and the probe fell into Mercury’s gravity pull, scientists at the control room in John Hopkin’s University started in a round of applause.

Mercury is the fifth planet that NASA spacecrafts have orbited. Mercury is the closest planet to the sun and lacks an atmosphere. This means that Mercury’s surface is super heated by the sun during daytime but drops to hundreds of degrees below freezing at night. Also, without an atmosphere, Mercury’s surface is heavily cratered. The vast temperature different implies that ice could be found inside the craters. The Mercury probe hopes to bring back a year of photography that would help in the research of the creation of Mercury and its composition. With this goal in mind, surveillance of the probe is needed for the next few days. Constant checks on the probe’s health systems, testing of the scientific equipment that is on board is essentially so that the vast amount of data can be collected and  transmitted back to Earth.

This massive project started in 2004 with a budget of $446 million. Hopefully, the probe will bring back valuable data that would useful for planetary scientists to determine the evolution of Mercury.

Messenger also hits close to UBC as one of the Earth and Ocean Science professors, Dr. Catherine Johnson, participated in the project. Dr. Johnson is a participating scientist in the project and hopes to discover the reasons behind Mercury’s magnetic field. The probe Messenger hopefully will gather data that will be of use to Dr. Johnson.

To boldly go ever after? The search for habitable planets.

Have you ever dreamed of exploring outer space? Of reaching up into the stars to venture where no person has gone before, exploring strange and exotic worlds all the while saving mankind from imminent destruction? From Star Wars to Battlestar Galactica the imaginative world of science fiction has painted a picture of the galaxy quite dissimilar from our own. Theirs is a universe filled with habitable-world’s innumerable star systems surrounded by small rocky planets. While this makes for compelling story-lines, until recently it was thought that this view couldn’t be farther from the truth.

Earlier this month it was released that NASA’s Kepler Mission, named in honour of German astronomer Johannes Kepler whose work laid the foundations for the laws of planetary motion, had discovered its first so-called Goldilock’s planets. A Goldilock’s planet is a terrestrial (rocky) planet of a similar size to Earth in an area known as the Circumstellar Habitable Zone. A system’s CHZ is a spherical region of space surrounding a star where a planet could theoretically possess the life’s essential element, water. In this zone, planets receive enough solar radiation to keep the bulk of the water above freeing, but not so much as to boil. In addition to being in the CHZ a Goldilock’s planet must also be within a region known as the Galactic Habitable Zone (GHZ). Along the same lines as the CHZ the GHZ is a region of the galaxy where it is thought that there is the highest possibility of finding habitable planets. It is far enough away from the galactic core as to not be severely affected by the high-energy radiation common there, but not too far as to be devoid of the heavier elements essential for the formation of terrestrial planets. In the Milky Way this regions starts at around 25,000 lights years from the galactic core and extends to about 32, 000 ly.

While the candidate planets discovered by the Kepler Mission will require careful follow-up to determine if they are indeed Earth-like planets, preliminary observations suggest that five of the fifty-four planet candidates in the CHZ are indeed terrestrial, and similar in size to our own. A new device from the Harvard-Smithsonian Centre for Astrophysics will likely play a key-role in verifying the characteristics of these new worlds. Knows as the High-Accuracy Radial velocity Planet Searcher or HARPS-North for short, the instrument soon to be installed in the Canary Islands will enable researchers to measure the tiny radial-velocity signal produced by small planets like the Earth. This data allows researchers to determine the densities of the target-planets enabling them to distinguish terrestrial worlds from their more common gas-based brethren.

While these five planets represent a tiny fraction of the over 1200 planet-candidates found thus far during the analysis of over 150,000 star systems discovered by the Kepler Mission, that they were all located in such a minuscule fraction of the galaxy suggests that a universe of boundless habitable-worlds might not be too outside the realm of possibilities.

References Cited:

  1. NASA (2011, February 2). NASA finds Earth-size planet candidates in habitable zone, six planet systemScienceDaily. Retrieved February 16, 2011, from http://www.sciencedaily.com­/releases/2011/02/110202133321.htm
  2. ANI. (2011, 2011-02-15). New device to help confirm kepler’s planetary candidates. The Wall Street Journal,
  3. Mori. (2007). Fermi , what paradox? (image credit). Retrieved 02/15, 2011, from http://forgetomori.com/2007/ufos/fermi-what-paradox/