A space shuttle astronaut was last night charged with attempted murder after allegedly attacking and trying to kidnap her rival in an apparent Nasa love triangle.

Captain Lisa Nowak, 43, who spent 13 days aboard the shuttle in July, told police that she was “involved in a relationship” with Commander William Oefelein, 41, a graduate of the US Navy’s “Top Gun” flight school who piloted a shuttle mission to the International Space Station in December.

She said that she had decided to act after learning that Commander Oefelein, nicknamed “Billy O”, was also involved with Colleen Shipman, a US air force captain assigned to a shuttle launch support unit.

According to the police report, the married mother of three drove from Houston to Orlando to confront her love rival after she had learnt that Captain Shipman was returning to her home near the Kennedy Space Centre in Florida.

Police said that Captain Nowak wore nappies for her mission so that she did not have to stop to urinate during the 950-mile drive from Houston - a technique used by astronauts during launch and reentry.

Disguised in a black wig and tan trenchcoat, Captain Nowak waited for Captain Shipman’s aircraft to land before dawn on Monday and then boarded an airport shuttle bus with her to the car park.

Hearing “running footsteps” behind her, Captain Shipman hurried to her car and locked herself inside, police said. Captain Nowak slapped the window and tugged at the door, asking Captain Shipman for a lift.

When Captain Shipman rolled down the window two inches, Captain Nowak allegedly sprayed her with a chemical that made her eyes burn, prompting her to drive off to seek help.

Police found Captain Nowak dumping two bags in a rubbish bin. They contained not just the discarded coat and black wig but also an airgun, a 4in penknife, a new steel mallet and several rubbish bags. Inside her car, police found pepper spray, latex gloves, directions to Captain Shipman’s home and nappies, including two soiled ones, “that Mrs Nowak admitted to using so she did not have to stop to urinate”.

Also in the car were copies of e-mails between Captain Shipman and Commander Oefelein, and “a letter that indicated how much Mrs Nowak loved Mr Oefelein”.

A police affidavit said: “The facts that Mrs Nowak drove approximately 900 miles, urinated in diapers so that she did not need to stop, stayed at a hotel where she paid in cash and used a false name and address to register, steathily followed her victim while in disguise and possessed multiple deadly weapons at the time she confronted the victim . . . gives this investigator probable cause to believe that Mrs Nowak intended to murder Mrs Shipman.”

Kelly Humphries, a spokesman at the Johnson Space Centre in Houston, Texas, said yesterday: “We do not really understand it any more than anyone else does. Nasa and all the folks here are basically stunned.”

Commander Oefelein has two children, but is reported to be divorced. Captain Shipman is believed to be single. Captain Nowak, who has a teenage son and twin five-year-old daughters, is a graduate of the US Naval Academy and a former test pilot who has logged 1,500 hours’ flight time on more than 30 types of aircraft. Her husband, Richard, works as flight controller for Nasa.

In her biography she lists her interests as running, playing piano and collecting African violets. She joined the Nasa programme in 1996 and made her first space flight as a robot-arm operator aboard the Discovery shuttle in July.

Although she has never gone into orbit with Commander Oefelein, the two trained together for 11 days in 2002 at a Canadian army cold-weather survival camp. Captain Nowak was originally charged with attempted kidnapping, attempted vehicle burglary and battery. But before the day was out prosecutors added a charge of attempted first-degree murder with a deadly weapon, which carries a possible life sentence.

Donald Lykkebak, her lawyer, called the astronaut’s actions a “mistake” but denied that she intended to kill Captain Shipman. “What she did was spray her with pepper spray, no more,” he said.

Amanda Cowan, the prosecutor, insisted, however, that the fact that Captain Nowak was carrying weapons in her bag when she accosted Captain Shipman showed an intention to kill her.

Judge Michael Murphy agreed to release Captain Nowak on $25,500 (£13,000) bail but ordered her to wear an electronic tracking device on her ankle and not to have any contact with the alleged victim.

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