NASA’s First Flight With Crew Important Step on Long-term Return to the Moon

Orion spacecraft (Credit: NASA)

WASHINGTON (NASA PR) — Astronauts on their first flight aboard NASA’s Orion spacecraft will travel farther into the solar system than humanity has ever traveled before. Their mission will be to confirm all of the spacecraft’s systems operate as designed in the actual environment of deep space with crew aboard. NASA’s first mission with crew will mark a significant step forward on NASA’s plans to return humans to the Moon for long-term exploration and future missions to worlds beyond, including Mars.

“During this mission, we have a number of tests designed to demonstrate critical functions, including mission planning, system performance, crew interfaces, and navigation and guidance in deep space.” said Bill Hill, deputy associate administrator, Exploration Systems Development, NASA Headquarters in Washington. “It’s just like the Mercury, Gemini, and Apollo programs, which built up and demonstrated their capabilities over a series of missions.”

Leaving Earth

The mission will launch from NASA’s Kennedy Space Center in Florida by 2023 on a Block 1 configuration of the Space Launch System (SLS) rocket. The plan for the flight is built around a profile called a hybrid free return trajectory where Orion will perform multiple maneuvers to raise its orbit and eventually place the crew on a free return trajectory from the Moon. Basically, the spacecraft will circle our planet twice while periodically firing its engines to build up enough speed to push it toward the Moon before looping back to Earth.

Credit: NASA

After launch, the spacecraft and upper stage of the SLS rocket will first orbit Earth twice to ensure its systems are working normally. Orion will reach a circular orbit at an altitude of 100 nautical miles and last 90 minutes. The move or burn to get the spacecraft into a specific orbit around a planet or other body in space is called orbital insertion.

Following the first orbit, the rocket’s interim cryogenic propulsion stage (ICPS) with an RL10 engine will perform an orbital raise, which will place Orion into a highly elliptical orbit around our planet. This is called the partial translunar injection. This second, larger orbit will take approximately 24 hours with Orion flying in an ellipse between 500 and 19,000 nautical miles above Earth. For perspective, the International Space Station orbits Earth from about 250 miles above our planet.

Once the integrated vehicle completes these two orbits, the ICPS will separate from Orion and the crew will do a unique test of the spacecraft’s critical systems. They will gather and evaluate engineering data from their day-long orbit before using Orion’s service module to complete a second and final propulsion move called the translunar injection (TLI) burn. This second burn will put Orion on a path toward the Moon.

“Free” ride home

The TLI will send crew around the backside of the moon where they will ultimately create a figure eight before Orion returns to Earth. Instead of requiring propulsion on the return, the spacecraft will use the Moon’s gravitational pull like a slingshot to bring Orion home, which is the free return portion of the trajectory. Crew will fly thousands of miles beyond the Moon, which is an average of 230,000 miles beyond the Earth.

A flexible mission length will allow NASA to gather valuable imagery data during daylight for the launch, landing and recovery phases. It will take a minimum of eight days to complete the mission, and pending additional analysis, it may be extended up to 21 days to complete additional flight test objectives.

Two missions, two different trajectories

The agency is scheduled to test SLS and Orion together for the first time without crew over the course of about three weeks in 2020. The hybrid free return trajectory will build upon testing in a distant lunar retrograde orbit, or DRO, for that first mission. The DRO will put Orion in a more challenging trajectory, and will be an opportunity to test the kind of maneuvers and environments the spacecraft will see on future exploration missions. The DRO will require additional propulsion moves throughout the trip, including a Moon flyby and return trajectory burns.

“Between the DRO on our first flight, and the hybrid free return trajectory on the second flight, we will demonstrate the full range of capabilities SLS and Orion need to operate in deep space,” said Hill.

Once these first two test flights are completed, Hill added that NASA hopes to begin launching missions once a year with crew, depending on budget and program performance, with initial missions focused on building of the Gateway around the Moon.

NASA is leading a return to the Moon through an innovative and sustainable program of exploration with commercial and international partners to enable human expansion across the solar system and to bring back to Earth new knowledge and opportunities. SLS’s unprecedented power and volume will also carry the large pieces of hardware needed to build the Gateway and other long-term infrastructure at the Moon and, later, for human missions to Mars. Together, SLS and Orion are critical backbone capabilities that will carry humans to the Moon and farther into space than ever before on a variety of missions in deep space with increasing complexity.