Days of Note

Dr. Derrick Pitts and Dave Heller recap some important dates in space exploration this week.
On February 1, 13 years ago, the Space Shuttle Columbia broke up on reentry. Seven astronauts were lost and the program was grounded for over two years while new safety measures were added. Afterwards all space shuttle missions (except the final Hubble repair mission) were flown to ISS so it could be used as a safe haven in case of other orbiter malfunctions.
Thursday Feb 2 is the first cross-quarter day of the year, Groundhog Day. Day length is now 10h 16m, gaining 15 minutes over last week.
110 years ago this Saturday, Clyde Tombaugh was born. Tombaugh discovered Pluto in 1930. Because of the New Horizons mission that flew by Pluto in 2015, we know that Pluto has a dense rocky core surrounded by a mantle of water ice covered by a thin layer of nitrogen ice. It’s only 1500 miles in diameter. The surface is amazingly diverse – from smooth to rocky to mountainous to cratered, it’s vastly different from whatever was expected. Pluto even has a thin atmosphere of photochemical hydrocarbon smog caused by sunlight’s interaction with methane and other molecules.
On Monday night, the moon, Venus and Mars begin their close encounter for the month. The three form a triangle Tuesday night. The International Space Station will also become visible on Tuesday night, 6:34 SW to NW to N, 33 degs max el; and again Wednesday night 5:45 p, passing to the right of the planets max ei. 59 degrees. From 6 – 6:30 a.m., Jupiter’s up in the south, Saturn’s in the east and Mercury is low in the east.