Archive
02/14/11 – Ephemeris – Stardust-NExT reaches Comet Tempel 1 tonight
St Valentine’s Day, Monday, February 14th. The sun will rise at 7:44. It’ll be up for 10 hours and 24 minutes, setting at 6:09. The moon, 3 days past first quarter, will set at 5:41 tomorrow morning.
About 11:40 this evening the Stardust spacecraft will pass about 120 miles from comet Tempel 1’s nucleus. It’s happening over 200 million miles away, near Mars’ distance from the sun. The spacecraft will take 72 pictures as it speeds past the comet at over 24,000 miles an hour. By tomorrow morning many of the photographs should be available on the Internet and TV. On Tempel 1’s last approach to Mars’ orbit it was struck bu a big chunk of copper when the Deep Impact spacecraft’s impactor struck the comet’s nucleus. That was July 4th, 2005. This time the Stardust-NExT mission is interested in changes in the comet that have occurred over the orbit, and it’s looking for the crater left by Deep Impact.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
01/27/11 – Ephemeris – Mars at superior conjunction
Thursday, January 27th. The sun will rise at 8:06. It’ll be up for 9 hours and 37 minutes, setting at 5:44. The moon, 1 day past last quarter, will rise at 3:46 tomorrow morning.
Starting today the planet Mars will be too close to the direction of the sun to send commands from the earth to Opportunity rover and satellites orbiting it.. The sun is noisy in the radio spectrum. This is seen in the spring and fall when geosynchronous satellite signals are lost when the satellite passes in front of the sun. This blackout isn’t total. The Mars Odyssey orbiter will be receiving data from te rover daily and relaying it back to the earth but at a very slow bit rate. The disruption of communications will last two weeks centered on February 4th when Mars will seem pass two sun diameters south of the sun. In reality it will be 129 million miles behind the sun. and 221 million miles from the earth.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
01/18/11 – Ephemeris – Antimatter from thunderstorms
Tuesday, January 18th. The sun will rise at 8:14. It’ll be up for 9 hours and 17 minutes, setting at 5:31. The moon, 1 day before full, will set at 7:51 tomorrow morning.
The Fermi gamma ray satellite has detected gamma rays from an unusual source. The Earth. Specifically from thunder storms. That isn’t the weird part. The gamma rays produced in the storm interact with electrons in the upper atmosphere producing a positron-electron pair that tangles with the earth’s magnetic field where Fermi detects it. Positrons are anti-electrons which can be produced artificially on the earth, and are used in medical PET scans. While scientists know how lightning is produced in a general way they do not know deep down the exact mechanism that produces lightning. That goes for thunderstorms on the earth and lightning in the atmospheres of the other planets. Lightning is still a mysterious phenomenon.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
01/11/11 – Ephemeris – Stardust spacecraft flyby of Comet Tempel 1 in 34 days
Tuesday, January 11th. The sun will rise at 8:17. It’ll be up for 9 hours and 5 minutes, setting at 5:23. The moon, 1 day before first quarter, will set at 1:08 tomorrow morning.
The Stardust spacecraft is 34 days from its flyby of the comet Tempel 1 on Valentine’s day. This is the comet visited and impacted by the spacecraft Deep Impact five and a half years ago, on the 4th of July 2005. The purpose of this flyby is to study the impact crater created by Deep Impact, and the changes in the comet’s nucleus since the last encounter. Comet’s undergo wear and tear as they approach the sun sublimating their ices and liberating dust that forms their head and tail. The Stardust spacecraft is having some problems. It hasn’t imaged the comet for fine guidance yet, and apparently it has less maneuvering fuel than initially thought. In order to image the impact crater the rotation period of the comet must be known to a great precision. I’m not sure they do.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
12/31/10 – Ephemeris – Space exploration events in 2011
New Years Eve, Friday, December 31st. The sun will rise at 8:19. It’ll be up for 8 hours and 52 minutes, setting at 5:11. The moon, 1 day before new, will rise at 5:54 tomorrow morning.
The year 2011 will be a great one for exploration of the solar system. Three NASA spacecraft will reach their targets. On Valentine’s Day the Stardust spacecraft will pass close to Comet Tempel 1, to see the changes in that comet in the 5 and a half years since the Deep Impact spacecraft hit that comet with a 600 pound chunk of copper. On March 18th, the MESSENGER spacecraft will attempt to enter orbit around Mercury after a seven year long journey. On July 16th the ion powered Dawn spacecraft will gently assume orbit of the asteroid Vesta. Vesta is one of the bigger asteroids, being second most massive and the brightest. It will orbit Vesta for a year before leaving for the dwarf planet Ceres.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
SpaceX does it again!
Today SpaceX made their second successful launch out of two attempts of their Falcon 9 rocket. They put their Dragon capsule in orbit, and returned it to land on target in the Pacific Ocean. As always Emily Lakdawalla of the Planetary Society has the information. This is fantastic news.
While just about all NASA rockets are built by private companies, they are built to NASA specifications in cost plus bids, which often have cost overruns. The plus in cost plus means the contractors are guaranteed profits. The new commercial firms design and build their own systems based on the general requirements provided by NASA. Whatever they come up with must of course be certified by NASA. NASA’s also paying, but it’s a fixed amount, so the companies can make out like a bandit, or lose their shirt.
Congratulations SpaceX!
Bob Moler's Ephemeris Blog 