Lunar Gateway is a space station that is being planned by international organizations, most of them are members of the International Space Station partnership. Gateway is a spacecraft that will be parked in a special lunar orbit usually referred to as a near rectilinear halo orbit or "NRHO". The NRHO is an important orbit for lunar missions. The orbit uses the L1 center of mass between Earth and the Moon.
NRHO is a highly inclined orbit around the moon and is considered to be in cislunar space. Cislunar space is used to refer to the space between and around Earth and the moon. Cislunar space includes various orbits such as Low Earth Orbit (LEO), Medium Earth Orbit, geosynchronous equatorial orbit (GEO), as well as other orbits, such as Low Lunar Orbit and NRHO, the intended orbit for the Gateway.
NRHO will carry Gateway in a polar orbit around the Moon in a seven-day cycle. In NHRO the spacecraft will travel as close as ~1,000 miles (1,600 km) and as far away as about 42,415 miles (68,260 km) from the lunar surface. This means a lunar lander can depart the Gateway to land on the lunar surface once every 7 days. In this orbit the will need little energy for stationkeeping or to maneuver into other cislunar orbits. Because Gateway will travel farther away around the L1 point, humans on the Gateway will be farther away than the human race has ever traveled.
NRHO provides an unobstructed view of Earth and coverage of the lunar South Pole. Another advantage of the Gateway's NRHO orbit is that the delta-v (energy) required to reach the surface of the moon is significantly smaller than Apollo missions needed. The orbit is considered an ideal staging area for missions to the Moon and beyond.
Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE)
NASA is scheduled to launch the CAPSTONE mission on June 27, 2022 using Rocket Lab’s Electron rocket. It will be launched from Rocket Lab's Launch Complex 1 in New Zealand, the company's primary launch site. NASA and partners will test new tools for mission planning and operations for exploration missions to the Moon, Mars and other destinations.
CAPSTONE carries a second flight computer and radio that will determine where the CubeSat is in its orbital path. Using NASA’s Lunar Reconnaissance Orbiter (LRO) that has orbited the Moon since 2009, CAPSTONE will communicate directly with LRO and use the data obtained to measure how far it is from LRO and how fast that distance changes. That information and its analysis should enable CAPSTONE to determine its position in space. The information will be used to evaluate CAPSTONE’s autonomous navigation software. This software is called Cislunar Autonomous Positioning System (CAPS). If successful, future spacecraft will be able to determine their location without help from Earth.
For a good overview of the CAPSTONE mission and the NRHO orbit, Check out Everyday Astrononaut's prelaunch summary: CAPSTONE/Electron.
Advanced Space of Boulder, CO owns and operates the CAPSTONE spacecraft for the entire mission. The Advanced Space team designed the mission orbits, oversaw the design and manufacture of the hardware, and will be perform flight operations in their Colorado office.
Other Members of the Advanced Space Team
Tyvak Nano-Satellite Systems based in California, Tyvak manufactured partner the satellite bus amd are responsible for the assembly and testing of the CAPSTONE’s subsystems.
Stellar Exploration, Inc., of California designed and manufactured CAPSTONE’s propulsion system.
Lunar Reconnaissance Orbiter launched on June 18, 2009, on an United Launch Alliance Atlas V rocket.
at Launch Complex 41 to begin the and Lunar Crater Observation and
It entered lunar orbit on June 23, 2009 and began its mission began on September 15, 2009.