While a Gulfstream is mainly known as a private jet, the aircraft once played a crucial role in the space industry. The Gulfstream II variation, first produced in 1967, was deployed by NASA in the 1980s as a means of training pilots in perfect landings of the NASA Space Shuttle orbiter.

NASA’s Space Shuttle program

As the fourth human spaceflight program, NASA’s space shuttle era changed history. The orbiter that launched with two reusable solid rocket boosters first flew on April 12, 1981, and, in 30 years, was crucial to many missions in space.

The fleet, including Columbia, Challenger, Discovery, Atlantic, and Endeavour, was part of constructing the International Space Station, performing services for the Hubble Space Telescope, recovering satellites, payloads, and flying astronauts into space.

The space shuttle was the first reusable spacecraft, launching into space vertically and landing like a plane. It operated 135 missions and sent 355 astronauts into space, but after the program became too expensive and too dangerous, the final shuttle mission operated on July 21, 2011, after the Atlantis parked at NASA’s Kennedy Space Center in Florida.

Shuttle Training Aircraft

Que the Gulfstream II private jet. The space shuttle orbiter was known as a ‘flying brick’ to the pilots who operated it, as it was complicated to maneuver, and landing was an all-in experience. Due to the nature of the orbiter, it couldn’t be trained on like an aircraft. Therefore, in 1973, NASA decided to modify four Grumman Gulfstream II jets to become a Shuttle Training Aircraft (STA).

The aircraft was altered to mimic the configuration and cockpit of the orbiter near-perfectly for training. Inside the aircraft were computers and simulators that made the pilots feel like they were flying an unpowered spacecraft, according to NASA. This meant that while the pilots were in charge of controlling the plane, the computer would decide how the real shuttle would react. NASA said:

“When the astronaut pulls the control stick back, for example, the computer decides how a real orbiter would react. Then the computer moves the wing and tail to make the STA act the same way. The movement takes a scant 50 milliseconds to occur, though, so the pilot senses no delay.”

The STA was built to reverse its engines in flight and operated with two sets of main landing wheels. NASA said that to match the shuttle’s descent rate and drag profile at 37,000 feet, the main landing gear was lowered, and the engine thrust was reversed. Plus, flaps would be deflected upwards to decrease lift.

In what was considered like “diving head first at a concrete strip six miles up,” according to NASA, the “landing pattern” of the spacecraft meant that the Gulfstream would fly at 300 mph during a dive, which is “several times steeper than that of an airliner.”

The space agency said covers were retrofitted onto the left hand of the cockpit windows to mimic the view astronauts would have from the shuttle cockpit. The right side of the cockpit had conventional controls and displays.

Nearing the runway, if the pilots got the speed correct, a green light on the instrument panel would simulate a landing when the pilot’s eyes were 32 feet above the runway, mimicking the exact position a pilot’s head would be in a real landing. NASA stated:

“In the exercise, the STA is still flying 20 feet (6 m) above the ground. The instructor pilot deselects the simulation mode, stows the thrust reversers, and executes a go-around, never--during practice approaches--actually landing the aircraft.”

Gulfstream II for NASA space shuttle training
Photo: NASA

The four STAs were usually located at the NASA Forward Operating Location in El Paso, Texas, and astronauts would practice at the Shuttle Landing Facility and White Sands Space Harbor.

Training on the Gulfstream

In 2007, NASA published an article about what it was like to fly the STA, with the input of Jack “Trip” Nickel, a research pilot, and Alyson Hickey, a flight simulations engineer.

The article said that the training aircraft was significant because, in the actual orbiter, commanders only got one chance to land the 110-ton spacecraft. This is because there are no chances for a go-around as the spacecraft doesn’t have the atmospheric engines to gain extra thrust, so performing a perfect landing was crucial. Nickel said:

“The shuttle has the flying characteristics of brick, basically, with wings. In a plane like this, a corporate jet, there is no sky visible out of the front cockpit. All you see out the window is dirt, there is absolutely no sky. So, it’s a very ominous feeling. With the engines in reverse thrust, you’re hanging in your harness,

"You get the real dynamics of real air going over the aircraft (and) you just can’t model that with a computer. There’s just no comparison to being out in the real air, seeing the real landing aids. This is just the real thing.”

During training, Nickel would ensure the aircraft’s safety, and Hickey monitored the computer and played the role of a shuttle pilot informing the astronauts onboard. During training, Hickey would sit behind and between the astronaut on the left and the instructor on the right.

Hickey would run the whole simulation and, partnering with Nickel, the two would throw in problems that could happen in real life for the practicing shuttle commander to solve.

Nickel said that this aircraft performed at the “structural airspeed limits in simulation (mode),” but the reward was realistic training for pilots who only get “one shot” at landing the spaceplane.

NASA's Columbia space shuttle
Photo: NASA

The aircraft's retirement

The Gulfstream was crucial to training astronauts on the difficult task of flying the shuttle orbiter. After thousands of hours and 946 flying days, the jet landed at the Rick Husband Amarillo International Airpot and taxied towards the Texas Air and Space Museum as its final resting place on September 21, 2011. Its retirement was synonymous with the closing of the shuttle program.

The aircraft is just one of several other aircraft models to be retired by NASA as the agency continues to adapt to modern requirements. Notably, a Boeing 747SP that carried a telescope for the Stratospheric Observatory for Infrared Astronomy (SOFIA) was retired last October. The unit was part of several game-changing missions,

The plane was previously utilized by Pan American and United Airlines before arriving at NASA’s facilities in 1996. It has been part of a series of discoveries across the universe.

Moreover, at the turn of 2023, NASA noted that it was preparing to let go of its aging DC-8 aircraft. The modified jetliner has been used as a flying laboratory, gathering crucial data in the world of space exploration. The 54-year-old makes way for a somewhat more modern aircraft in the form of a Boeing 777.

Altogether, NASA has well-deployed a range of commercial and civilian models for its adventures above. This factor will remain prevalent in this next chapter in aviation, with the group continuing to collaborate with US manufacturers. Earlier this year, it awarded Boeing with a sustainable flight contract with the hopes of producing a full-scale demonstrator over the next five years.

What are your thoughts about when NASA used a Gulfstream II to train space shuttle pilots? What do you make of the overall initiative? Let us know what you think of the agency's different programs using various types of aircraft in the comment section.

Source: NASA