Everyone seems to know that Texas is called “the Lone Star state,” but just try asking people where the nickname comes from, and even some Texans don’t know the answer.
Well, I did some digging, and found several theories, the predominant one being that that Texas is the only U.S. state that was a Republic at one point in its history. The star on the state flag symbolizes this, as well as the state’s fight for independence from Mexico in the mid 1800s.
This is also the reason why Texas is the only state that’s allowed to fly its flag at the same height as the American flag.
Most of the other theories also trace the flag’s history back to the bloody fight by the Mexican state of Tejas for its independence, which included on its timeline the defense of the Alamo.
Here’s a summary from a good website on Texas symbolism:
“Lone Star State – A single star was part of the Long Expedition (1819), Austin Colony (1821) and several flags of the early Republic of Texas. Some say that the star represented the wish of many Texans to achieve statehood in the United States. Others say it originally represented Texas as the lone state of Mexico which was attempting to uphold its rights under the Mexican Constitution of 1824. At least one “lone star” flag was flown during the Battle of Concepcion and the Siege of Bexar (1835). Joanna Troutman’s flag with a single blue star was raised over Velasco on January 8, 1836. Another flag with a single star was raised at the Alamo (1836) according to a journal entry by David Crockett. One carried by General Sam Houston’s Texian army (which defeated Mexican General Santa Anna at the Battle of San Jacinto ) may have been captured and taken to Mexico. Another “lone star” flag, similar to the current one but with the red stripe above the white, was also captured the following year (1837) and returned to Mexico. The “David G. Burnet” flag, of “an azure ground” (blue background) “with a large golden star central” was adopted by the Congress of the Republic of Texas in December of 1836. It continued in use as a battle flag after being superseded in January of 1839. The 1839 design has been used to symbolize the Republic and the “Lone Star State” ever since.”
This Lone Star question came up on our drive across Texas, which included stops in Fort Stockton, San Antonio, Austin and Houston.
We couldn’t pass through San Antonio without going to the Alamo for a history lesson. I’m glad we did, because my recollection of what happened there was way, way off…
One other must-do was the NASA space shuttle flight-landing simulator at the Johnson Space Center in Houston. If I might brag, Ethan set a record for the day and was deservedly very proud of himself!
One final note about Texas, we took a tour of the space center (run by a pair of lazy, bored, disinterested teenagers who kept calling us “you guys”) and we got to see the historic NASA Mission Control room, 
where all shuttle flights were monitored and controlled until the early 1990s. At that point MC moved down the hall to a room where the computers actually had keyboards!
More recently the old MC was used for filming of the movie Apollo 13, which Ethan and I enjoyed watching again a few days after our NASA tour.
Next stop: New Orleans
An aside from Ethan’s uncle: Ethan’s grandfather was a science journalist and covered the space program from its beginning to the shuttle. He was in the JSC press room when the voice of his friend, Apollo 13 captain Jim Lovell, announced, “Houston, we have a problem.”