Rockets at the Alamo?

George Hockley, Secretary of War, Republic of Texas initially rejected the New Colt repeating rifles and revolvers (Patterson Revolvers) in favor of Congreve rockets. Saying the revolvers were too complicated for any but the most experienced of troops, and would waste ammunition and time in their use against Indians, while Congreve Rockets would… “ excite terror and probable confusion.” Fortunately President Lamar overruled him and ordered the new Colts for the Texas Navy and later issued them to the Texas Rangers who used them to great effect against the Comanche.

Rockets in San Antonio on March 6, 1836 were mentioned by Almonte's cook, Ben, and by "a Mexican deserter" (who told Jesse Badgett that a rocket signal had begun the attack). Mrs. Dickinson, in an interview years later, also noted that a rocket had signalled the attack. There are at least five contemporary references to General Cos' troops using them in San Antonio and the Alamo in 1835 as well.
During the Mexican War the Mexican Army also had rockets tipped with warheads that were fired directly at American troops.

this reference also.

“… it were narrated to me by a gentleman formerly an officer in the Texan army, which he had obtained from Santa Anna's servant, who after the battle of San Jacinto was cook for Gen. Houston. The statements of this servant were generally relied on by those who knew him, … That accompanied by his private Secretary the General went out about 11 o'clock and did not return until 3 in the morning ; that he served them with coffee of which Santa Anna took but little, and seemed much excited, and observed, to Almonte, that if the garrison could be induced to surrender, he would be content; for said he, if they will not, I well know, that every man before the dawn of clay must, unprepared, meet his God. But what more can I do ; my summonses, said he, are treated with disdain ; it appears to me the only alternative presented is to assault the garrison; we cannot delay longer here wasting the resources of the nation and any termination of the affair will relieve, me of a load of anxiety. He further stated that at 4 o'clock Santa Anna and other officers left the house, and very soon a tremendous discharge of cannon told that the work of death was began ; he saw rockets in awful brilliancy blazing through the darkness of the night, and the walls and grounds of the Alamo reflected the light so that from a window he could plainly perceive columns of Mexican troops around the fort and ascending the walls on ladders, and that the whole interior of the Alamo was perfectly illuminated, as he supposed, by the firing of the Americans within ; and that the old servant feelingly remarked that he liked master Santa Anna, but that when he heard the thunders of the artillery and saw blazing rockets gleaming through the air, he thought of Master George Washington and old Virginia, and prayed to God that the Americans might whip. “

THE TEXAN EMIGRANT: BEING A NARRATION OF THE ADVENTURES OF THE AUTHOR IN TEXAS, AND A DESCRIPTION OF THE SOIL, CLIMATE, PRODUCTIONS, MINERALS, TOWNS, BAYS, HARBORS, RIVERS, INSTITUTIONS, AND MANNERS AND CUSTOMS OF THE INHABITANTS OF THAT COUNTRY : TOGETHER WITH THE PRINCIPAL INCIDENTS OF FIFTEEN ...
By Col. Edward Stiff
Published by G. Conclin,
Cincinnati, 1840
Page 314