Henry Ruggs was traveling 156 MPH seconds before Tuesday's crash, slamming into the back of a Toyota at 127 MPH, with a blood alcohol level twice the legal limit, killing a 23-year-old woman, officials say.

Ruggs appeared in court this morning for the first time with a gash on his face, wearing a neck brace, to answer charges he caused the fatal car wreck in Las Vegas.

The details are disturbing. Officials, in new documents obtained by TMZ Sports, say they examined the computer in Ruggs' car and determined he was going incredibly fast just moments before he plowed into the Toyota.

Law enforcement said in the docs he was only able to slow to 127 MPH at the time of impact.

Officials says both Ruggs' car and the Toyota rolled over 500 feet after the initial impact ... where the Rav4 caught on fire.

In addition to the 23-year-old woman who perished, she also had a dog in the car that died.

Officers say Ruggs -- who appeared to be impaired at the scene -- refused to participate in field sobriety tests ... before he was eventually transported to the hospital.

Police say during an investigation following the crash, they located a gun in Ruggs' Corvette.

Officials added at Ruggs' hearing that bloodwork revealed the NFL player had a BAC of .161 -- more than two times the legal limit of .08.

Ruggs' injuries are unknown at this time -- though police did say the wounds were "serious" in documents. His mug shot shows the gash on his face was deep.

Ruggs has been charged with DUI resulting in substantial bodily harm, and reckless driving. His bail was set at $150,000.

The judge banned Ruggs from consuming alcohol ... and also ordered him to abstain from driving. He also must wear an electronic monitoring device as part of his bail.

At the hearing, the judge noted he'd never seen a case where the defendant was traveling at such a high rate of speed.