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NASA is expected to fly CubeSat pathfinder for Gateway in a unique lunar orbit – Spaceflight Now

The highly elliptical, approximately rectilinear halo orbit around the Moon uses a precise balance point in Earth and Moon gravity and provides stability ideal for long-term missions such as Gateway. Source: Advanced Space

Next year, NASA plans to release a microwave-sized CubeSat into a unique elliptical orbit around the Moon as a reconnaissance for the future Moon Gate, NASA intends to use the mini-space station as a stopping place for the Moon landing crew as early as 2024.

The commercially built CubeSat, called CAPSTONE, will conduct space navigation experiments and demonstrate maneuvers to enter and operate on the almost rectilinear orbit of the halo, the elliptical orbit around the Moon, which will be home to Gateway, a key element of NASA's architecture to bring people back to the surface of the Moon.

The Trump administration recommended NASA to attempt a moon landing with crew by the end of 2024. Earlier this year, NASA called the lunar program Artemis, the twin sister of Apollo in Greek mythology.

Together with the Orion crew ferry capsule, the Space Launch System heavy rocket and the new lunar lander, Gateway is a core element of NASA's Artemis program.

The first section of the Gate, known as the Power and Drive Element, is expected to be launched at the end of 2022. PPE will be built by Maxar Technologies in cooperation with several companies, including Blue Origin, that could provide a starter vehicle for the first gate element.

The module providing basic living quarters for astronauts will be launched at the end of 2023. NASA chose Northrop Grumman for a single supplier exclusive agreement, it also built a Gateway residential post that will come from a Cygnus supply ship that carries cargo to the International Space Station.

In the meantime, according to NASA's current plans, SLS will launch during the first test flight – probably not earlier than in 2021 – with the underrated Orion spacecraft on a more or less circular, so-called distant back orbit around the moon. A crew of four could start in 2022 or 2023. During the next SLS / Orion mission and fly on one loop around the moon – without entering lunar orbit – before returning to Earth on a free return trajectory.

Before launching the first Gateway element for the first time, CAPSTONE NASA will explore the almost straight orbit of halo or NRHO.

"Gateway is not dependent on this mission, but CAPSTONE will probably be the first spacecraft in an almost rectilinear orbit halo, and this is a dynamic environment … (with) the influence of many gravitational bodies," said Christopher Baker, NASA's small spacecraft technology program manager. "So CAPSTONE will help us reduce logistic uncertainty by checking what our models tell us, including the dynamics of entering NRHO, staying in orbit, low-energy supply trajectories for Gateway … and then this is also a technical demonstration of a peer-type navigation solution for peers" peer for cislunar space. "

CAPSTONE stands for Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment.

The near-straight orbit of the halo will take the spacecraft CAPSTONE, and eventually the Gate, so close to 1,000 miles (1,500 kilometers) and up to 43,500 miles (70,000 kilometers) from the moon.

The orbit chosen for the Gate "is the orbit of the Moon, but it is more of an orbit between Earth and the Moon," said Marshall Smith, director of human exploration programs for the moon.

The almost straight orbit halo has many advantages, said Smith on Thursday in a presentation for National Academies & # 39; Aeronautics and Space Engineering Board.

The station in such orbit will have a continuous communication connection with Earth and will allow landers leaving the Gate to reach anywhere on the Moon's surface with only low fuel consumption.

Illustration of the artist depicting the Gate in orbit around the moon, with an element of power and propulsion, a housing module and a visiting supply ship and capsule of the Orion crew. Source: NASA

A station like Gateway is needed because the Orion spacecraft, which will carry crews to and from the Moon, cannot be maneuvered directly into orbit from a low-altitude orbit, as did the Apollo spacecraft in the 1960s and '70s .

"We've been following orbits for quite some time," said Smith on Thursday.

The Orion spacecraft was originally developed in the mid-2000 for the NASA Constellation lunar program under George & # 39; a W. Bush. The delayed Constellation program was canceled in 2010, and the Obama administration wanted to skip the moon landing program and focus on the Mars expedition.

A constellation of the Orion spacecraft would have a US-built service module that includes rocket ship engines and energy generating solar arrays.

Smith said the U.S. service module would be able to change the speed of an Orion spacecraft in space by up to 4,000 miles per hour or 1,800 meters per second.

"Great, we could go into low lunar orbit and do everything we wanted," said Smith. "But at some point we decided that we would not go to the Moon for Constellation … and we wanted to have an international partnership."

The total speed change (Delta V) provided by Europeans' Orion spacecraft service module during one mission is about 2700 miles per hour (1200 meters per second).

"It's not enough to go to low lunar orbit (and return to Earth)," said Smith. "But we didn't go to the moon. we're going to the moon because we're going to Mars … So we made a change to do it.

"We're able to put Orion in a low lunar orbit," said Smith on Thursday. "We can't get it out because it doesn't have sufficient delta-V value, which is a problem. SLS can put it there … That's not the point. Many people blame SLS for this. This is not SLS. This is an ESA service module that has no delta-V.

"So we're limiting our capabilities in Orion, so we need to look at higher orbits, and what we want to do is get close to the moon," said Smith.

This is what the rectilinear halo orbit provides. A more circular orbit further away from the moon, such as a distant backward orbit previously preferred for a Mars-oriented opposing base, would require a lunar lander to carry greater propulsion to fly to the moon's surface and return to space.

"We want to make sure that the descent and climb (lander) elements have the lowest delta-V value possible," said Smith. "So we want to come up close (to the moon in every orbit). It is NRHO that allows us to approach closely. "

Smith said on Thursday that the latest NASA award is "inevitable" for US companies to propose human-rated lander designs. By the end of the year, NASA intends to select up to four companies to refine its lunar lander projects.

This assumes that NASA will receive an additional $ 1 billion from Congress in its budget for the financial year 2020, for funding requested by the Trump administration earlier this year to begin efforts to develop lunar landers. The rest of the $ 1.6 billion budget increase proposed by the White House for the Artemis program included money to maintain the development schedule of the SLS and Orion programs to meet the Trump administration deadline in 2024.

NASA's lunar program accelerated its landing on the moon in 2028, before Vice President Mike Pence charged the agency in March to move the schedule up four years.

The Budget Act for the financial year 2020, adopted by the House of Representatives in June, did not include $ 1.6 billion in additional funds for the Artemis program. The bill of funds highlighted by the Senate Committee on Funds this week proposed $ 744 million for the development of landing lunar landers, or $ 256 million less than what NASA thought was needed.

Illustration of Cislunar Autonomous Positioning System Operations and Navigation Experiment (CAPSTONE).
Source: Tyvak Nano-Satellite Systems

While funding for the moon landing in 2024 remains uncertain, NASA is moving forward with the Gate.

NASA announced on September 13 that it had awarded a $ 13.7 million Advanced Space contract to a small company based in Boulder, Colorado for the development and maintenance of CAPSTONE CubeSat.

"CAPSTONE will be the first satellite mission to be commanded by Advanced Space," wrote Bradley Cheetham, president and CEO of Advanced Space. "As a company, we supported mission planning and activities of partners and clients, but this will be our first mission as the most important. It is an exciting opportunity for us to demonstrate and improve mission support technologies in a fast and accessible way. "

In a statement, NASA described CAPSTONE as a "rapid demonstration of the lunar flight," which could begin as early as December 2020.

"This mission is very ambitious in terms of both costs and timing – and taking conscious risk is part of the mission's goal – alongside rapid technological progress in cislunar navigation and the ability to verify orbital trajectory assumptions and withdraw from the unknowns for future missions," said Jim Reuter , deputy administrator at NASA's Directorate for Space Technology.

CAPSTONE will wear a communication system that will determine its range based on NASA's Lunar Recognition Orbiter and how quickly the distance changes. The experiment will show software for autonomous navigation in space – well above GPS satellites – enabling future spacecraft to position them without relying on Earth tracking.

"Ultimately, we need to enable navigation with less dependence on Earth," said Baker in an interview with Spaceflight Now. "So if one mission, in this case LRO, is able to determine its location based on communication with Earth's resources, and another mission, such as CAPSTONE, is able to determine its relative position relative to this spacecraft, then CAPSTONE and any other ship a cosmic like him can find out where he is in space, without having to rely on Earth's direct support for this navigational aid. "

CAPSTONE will carry a small camera, but no other charges.

"In addition to the equipment for the navigation experiment, there is a camera, but in order to move quickly and adhere to the CubeSat ethos, we are really trying to keep the spacecraft as focused on this basic mission as possible," said Baker.

The CAPSTONE spacecraft is funded by NASA's space technology directorate. Baker said the agency's aviation department would pay for the launch of a commercial rocket on a commercial rocket as an extra charge on a large booster or aboard a special launcher.

"A shared ride or dedicated small starter vehicle is in the (possible) sphere," said Baker. "We want to do it quickly, cheaply and using a commercial vehicle."

Approximately three months after the start, CAPSTONE will use its own propulsion system – powered by green fuel or hydrazine fuel – to direct it to the nearby planned straight orbit halo.

"It's actually part of the experiment that involves using this propulsion system to get to this nearby rectilinear halo orbit and then maintain position in this nearby rectilinear halo orbit," Baker said. "We are currently trying to use green fuel. Hydrazine is a backup. "

According to NASA, CAPSTONE's basic mission is expected to last about six months after arriving in orbit around the moon.

Advanced Space is developing the CAPSTONE lunar navigation experiment and will be managing the NASA mission. Tyvak Nano-Satellite Systems, a smallsat builder in California, will produce the CAPSTONE spacecraft platform.

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Follow Stephen Clark on Twitter: @ StephenClark1.

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