Video games – Growing up I was a huge video gamer. Had the NEs, SNES, N64, Game boy (original, pocket, color, SP and the DS), PlayStation and the PlayStation 2.
Check out the Video Games category.
Web Design – Stating at about age 7 or 8 I started to teach myself web design from how-to magazine articles from a local free computer mag. For my birthday that year I got webhosting. I got more into it in high school and studied it in college.
See: A brief history of The Wizard’s Sanctum Sanctorum.
Posted a updated copy of my observation log in the astronomy section.
Messier 7 – Been able to find M7 twice in the last few days using binoculars.
Messier 45 – With the light pollution where I live, M45 is best seen with a low power pair if binoculars.
The moon – I haven’t been watching the moon as much as I was last month.
Early this morning NASA’s Curiosity rover sucessfully landed on Mars.
Launched on Cape Canaveral Air Force Station Space Launch Complex 41 from Cape Canaveral Air Force Station Space Launch Complex 41 using a Atlas V, the Mars Science Laboratory, dubbed “Curiosity” traveled approximately 352 million miles to the red planet.
The landing, nicknamed ‘seven minutes of terror’ involved ‘six vehicle configurations, 76 pyrotechnic devices, the largest supersonic parachute ever built, and more than 500,000 lines of code’.
The spacecraft employed several systems in a precise order, with the entry, descent and landing sequence broken down into four parts.
Guided entry: The rover is folded up within an aeroshell that protects it during the travel through space and during the atmospheric entry at Mars. Ten minutes before atmospheric entry the aeroshell separates from the cruise stage that provided power, communications and propulsion during the long flight to Mars. One minute after separation from the cruise stage thrusters on the aeroshell fire to cancel out the spacecraft’s 2-rpm rotation and achieve an orientation with the heat shield facing Mars in preparation for Atmospheric entry. The heat shield is made of phenolic impregnated carbon ablator. The 4.5 m (15 ft) diameter heat shield, which is the largest heat shield ever flown in space, reduces the velocity of the spacecraft by ablation against the Martian atmosphere, from the atmospheric interface velocity of approximately 5.8 km/s (3.6 mi/s) down to approximately 470 m/s (1,500 ft/s), where parachute deployment is possible about four minutes later. One minute and 15 seconds after entry the heat shield will experience peak temperatures of up to 3,800 °F (2,090 °C) as atmospheric pressure converts kinetic energy into heat. Ten seconds after peak heating, that deceleration will max out at 15 g. Much of the reduction of the landing precision error is accomplished by an entry guidance algorithm, derived from the algorithm used for guidance of the Apollo Command Modules returning to Earth in the Apollo space program. This guidance uses the lifting force experienced by the aeroshell to “fly out” any detected error in range and thereby arrive at the targeted landing site. In order for the aeroshell to have lift, its center of mass is offset from the axial centerline that results in an off-center trim angle in atmospheric flight. This is accomplished by a series of ejectable ballast masses consisting of two 165 pound (75 kg) tungsten weights that are jettisoned minutes before atmospheric entry. The lift vector is controlled by four sets of two Reaction Control System (RCS) thrusters that produce approximately 500 N (110 lbf) of thrust per pair. This ability to change the pointing of the direction of lift allows the spacecraft to react to the ambient environment, and steer toward the landing zone. Prior to parachute deployment the entry vehicle must eject more ballast mass consisting of six 55 lb (25 kg) tungsten weights such that the center of gravity offset is removed.
Parachute descent: When the entry phase is complete and the capsule has slowed to Mach 1.7 or 578 m/s (1,900 ft/s) and at about 10 km (6.2 mi) the supersonic parachute will deploy, as was done by previous landers such as Viking, Mars Pathfinder and the Mars Exploration Rovers. The parachute has 80 suspension lines, is over 50 m (160 ft) long, and is about 16 m (52 ft) in diameter. The parachute is capable of being deployed at Mach 2.2 and can generate up to 289 kN (65,000 lbf) of drag force in the Martian atmosphere. After the parachute has deployed, the heat shield will separate and fall away. A camera beneath the rover will acquire about 5 frames per second (with resolution of 1600×1200 pixels) below 3.7 km (2.3 mi) during a period of about 2 minutes until the rover sensors confirms successful landing.
Powered descent: Following the parachute braking, at about 1.8 km (1.1 mi) altitude, still travelling at about 100 m/s (220 mph), the rover and descent stage drop out of the aeroshell. The descent stage is a platform above the rover with 8 variable thrust mono propellant hydrazine rocket thrusters on arms extending around this platform to slow the descent. Each rocket thruster, called a Mars Lander Engine (MLE), produces 400 N (90 lbf) to 3,100 N (700 lbf) of thrust and were derived from those used on the Viking landers. Meanwhile, the rover will transform from its stowed flight configuration to a landing configuration while being lowered beneath the descent stage by the “sky crane” system.
Sky crane: For several reasons a different landing system was chosen for MSL compared to previous Mars landers and rovers. Curiosity was considered too heavy to use the airbag landing system as used on the Mars Pathfinder and Mars Exploration. A legged lander approach would have caused several design problems. It would have needed to have engines high enough above the ground when landing to not form a dust cloud that could damage the rover’s instruments. This would have required long landing legs that would need to have significant width to keep the center of gravity low. A legged Lander would have also required ramps so the rover could drive down to the surface, which would incurred extra risk to the mission on the chance rocks or tilt would prevent Curiosity from being able to drive off the lander successfully. Faced with these challenges, the MSL engineers came up with a novel alternative solution: the sky crane. The sky crane system will lower the rover with a 25 ft (7.6 m) tether to a soft landing—wheels down—on the surface of Mars. This system consists of 3 bridles lowering the rover and an umbilical cable carrying electrical signals between the descent stage and rover. As the support and data cables unreel, the rover’s six motorized wheels will snap into position. At roughly 7.5 m (25 ft) below the descent stage the sky crane system slows to a halt and the rover touches down. After the rover touches down it waits 2 seconds to confirm that it is on solid ground by detecting the weight on the wheels and fires several pyros (small explosive devices) activating cable cutters on the bridle and umbilical cords to free itself from the descent stage. The descent stage flies away to a crash landing at least 500 ft (150 m) away, and possibly twice that far. The sky crane powered descent landing system had never been used in missions before.
Withen minutes of landing the MSL had send back its first pictures.
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I remember 8 years ago, walking into a local webhosting company, ploping down my money to buy a domain name and 3 months hosting. Several idea changed, site redesigns, new sections added, retired sections archived and removed. At times I was easly spending 30 – 40 hours a weeks on updating and tweeking the site. Now I spend a few hours doing updates as needed.
I have been reading up on begining star gazing and wanting to put my new knowledge to use, however the weather has been uncoopative. TS Debbie has hereby sitting in the gulf of Mexico covering Florida in clouds and rain. Tonight I took the dog out and was greeted to the moon and two stars.