Space Sunday: JWST, Artemis and rockets delivering cargo to Earth

JWST art. Credit stsci.edu

The James Webb Space Telescope (JWST) is due to enter its initial halo orbit around the Earth-Sun L2 position, 1.6 million kilometres beyond Earth’s orbit around the Sun, on Monday, January 24th, 2022.

With the deployment of its major external elements completed, the observatory has been engaged in the first phase of a sensitive operation to correctly align the 18 hexagonal segments of its primary mirror so it perfectly reflects light into the boom-mounted secondary mirror and thence back into the telescope’s interior for delivery to its space science payload.

This first part of what is an extensive operation saw all 18 segments gently eased 12.5 mm away from the mirror’s backing structure, each segment being propelled forward by six tiny motors, referred to actuators. This allowed each mirror segment to be gently moved away from the restraints that held it in place during launch, and provides enough space behind each segment so it can be gently adjusted to align with its companions as the alignment process continues, all of them coming together to form a single, focused parabola.

When it starts, the latter part of the work will involve the actuators moving in the micron and nanometre ranges of movement, and once started, is expected to continue for around 40 days.

However, before that process begins, at 19:00 UTC on Monday, January 24th, JWST will fire its thrusters to ease itself into its initial halo orbit around the Earth-Sun L2 position, marking its arrival in the area of space where it will operate.

Thanks to the sheer accuracy of the Ariane 5 launch vehicle and the “mid-course” correction thruster burns JWST has made en route to this point, it has been calculated the observatory currently has sufficient propellant reserves for at least 10 years of operations. If the insertion burn proves to be as accurate, mitigating any need for it to be further refined, then JWST may have its overall mission length extended a little more.

JWST is due to enter its Earth-Sun L2 Halo orbit on Monday, January 24th, 2022. Credit: NASA

Once safety inserted around the L2 point, the telescope will go through an additional period of cooling adjustment to bring its instruments down to their operational temperatures. This process, which will actually use heaters to ensure heat dissipation is properly controlled, will take a number of weeks to complete, after which the primary mirror alignment process will resume, allowing scientific instrument calibration to commence.

Artemis: No Immediate Second Lunar Landing

After landing astronauts on the Moon in the mid-2020s for the first time in more than a half-century, NASA will wait at least two further years before making a second crewed lunar landing as part of the Artemis program.

Artemis 3 is due to deliver a crew of 2 to the lunar surface in around 2025. However, the next mission slated for Artemis will not follow it to the lunar Surface. Instead, and as indicated at a two-day meeting of the NASA Advisory Council’s Human Exploration and Operations Committee on January 18th/19th, it was indicated that the Artemis 4 mission will target the assembly of the Lunar Gateway.

This is the space station that will be placed in cislunar orbit and used as a transfer station for crews arriving from Earth aboard NASA’s Orion capsule and the Human landing System (HLS) vehicles that will carry them to the surface of the Moon and back. The first elements of the Gateway, the Power and Propulsion Element and Habitation and Logistics Outpost, will be launched together via a SpaceX Falcon Heavy in late 2024. They will then spend a year spiralling around the Moon and settling into their halo orbit.

Artemis 4, which will feature the Block 1B Space Launch System rocket using the powerful Exploration Upper Stage (EUS), intended for heavy cargo launches and deep space missions will carry the International Habitat Module (I-Hab) for the gateway, along with a crewed Orion vehicle that will oversee attaching I-Hab to the Gateway modules already in lunar orbit.

Whilst conceptual in terms of what the Lunar Gateway might eventually become, this image indicates the core NASA NASA elements  – the Power and Propulsion Element and the Habitation and Logistics Output module (which will actually be docked one to the other) to be launched in 2024, and the JAXA / ESA I-Hab module, to be launched in 2025 as part of the Artemis 4 mission. The Orion capsule + service module are also shown. Credit:  NASA

Even with the more powerful EUS replacing the Interim Cryogenic Propulsion Stage that will fly on Artemis 1-3, the Gateway flight of Artemis 4 will be a challenge for the SLS. The Block 1B vehicle will be capable of delivering around 38 tonnes to lunar orbit – and some 27 tonnes of that capability will be taken up by the Orion crew capsule and its service module. That means the European and Japanese space agencies, responsible for providing I-Hab for Artemis, must ensure the module masses no more than 10 tonnes. By comparison, similar modules on the ISS average around 12-12.5 tonnes.

A further reason for focusing Artemis 4 on Lunar Gateway activities is that NASA will not actually have any HLS vehicle(s) at its disposal for lunar landings for a period of time after Artemis 3. In awarding the initial HLS contract to SpaceX to develop a lunar landing variant of its Starship vehicle, NASA did so on the basis of using only a single lunar landing. Once it returns to orbit, the SpaceX HLS will require refuelling in order to make a second trip – and currently, NASA has indicated that it would rather await a “sustainable” HLS system  – to be developed under a new, yet-to-be awarded contract called Lunar Exploration Transportation Services (LETS).

NASA HLS; the current contract with SpaceX is only for a single HLS vehicle (centre). After Artemis 3, the first lunar landing, NASA will be relying on a “sustainable” HLS design – yet to be contracted – which might be Dynetic’s versatile design (l), or the Blue-Origin led design (r), both of which originally competed against SpaceX for the initial HLS contract, or might be provided by another supplier. Credit: Dynetics / SpaceX / Blue Origin

Exactly what is so happen to the SpaceX HLS after Artemis 3 is unclear. That mission will not use the Lunar Gateway, but will see an Orion dock with the SpaceX vehicle in lunar orbit for the 2-person crew transfer. As such, it is entirely possible the SpaceX HLS might simply be “parked” in lunar orbit and left.

However, given any LETS contract has yet to be granted a further crewed landing on the Moon under the Artemis banner is unlikely to occur before late 2027 or (more likely) 2028 / 29.

US Air Force Looks to Rockets for Point-to-Point Cargo Delivery

The US Air Force is undertaking a major study into the use of rocket systems to deliver military cargo and humanitarian aid from the United States to anywhere in the world where a suitable landing area exists.

Under the terms of the Rocket Cargo Programme, the USAF initially signed a contract with SpaceX and a company called Exploration Architecture Corporation (XArc) in 2020 to study concepts for rapid transportation through space. At the start of 2022, the Air Force has awarded SpaceX US $102 million to allow the Air Force Research Laboratory (AFRL) to access to SpaceX’s commercial orbital launches and booster landings to collect key data on environments, landing signatures and vehicle performance.

The US Air Force is interested in the potential to deliver a heavy lift cargo launch vehicle that could be used to lift supplies, equipment, etc., into orbit, and then bring them back to Earth in a controlled landing at or close to where they are needed, such as the location of a natural disaster (point-to-point transfer). Credit: Air Force Research Laboratory

In addition, and as part of the contract, SpaceX will provide cargo bay designs that support rapid load and unload and are compatible with U.S. TRANSCOM intermodal containers, and the contract also includes an option for a full-up demonstration of heavy cargo transport and landing.

No specific SpaceX launcher has been singled for use at this stage – although it is clear the core data AFRL will have access to is for the Falcon 9 booster. They will also likely have access to data gathered through further flight testing of SpaceX’s Starship vehicle – currently the only launch vehicle potentially capable of delivering heavy cargo from orbit to Earth.

SpaceX is unlikely to be the only participant in the study: the US Air Force has also entered into an R&D contract with Blue Origin, a company developing its only heavy lift launch vehicle with a return to Earth capability ib the form of their New Glenn rocket.

In entering the contract, the US Air Force has heavily emphasised the use of a point-to-point launch / landing system in humanitarian and disaster relief operations, allowing large amounts of medical supplies and associated relief cargoes – tents, food, water, clothing – to be rapidly delivered close to or at disaster site, using either prepared (e.g. existing roads or local airports) or “austere” (e.g. rapidly cleared and levelled) landing points.

Dust Storms Impact NASA Mars Surface Operations

It is dust storm season on Mars, and two of NASA’s mission in particular have been affected.

In the high northern latitudes, home to the InSight lander, which has been studying the interior of Mars since its arrival on November 28th, 2018 (see: Space Sunday: insight on InSight for details on the overall mission), became caught in the midst of a dust storm that blew up over the New Year period, giving rise to serious concerns about the lander’s future, the volume of dust in the atmosphere seriously reducing the amount of sunlight reaching the lander’s twin 2.5 metre diameter solar arrays, causing it to place itself into a “safe” mode on January 7th, 2022.

This was of concern, as between November 2018 and February 2021, dust build-up on the lander’s 2-5 metre diameter solar panels had reduced the lander’s power generate capability to just 27%. As a result, several of the science instruments to be turned off. Now the worry was, with the solar panels already generating much lower levels of electrical power, and reduction in sunlight might leave InSight’s batteries with insufficient power to be able to restore it to the remaining science instruments.

An artist’s impression of the NASA InSight lander on Mars. Credit: NASA

However, on January 19th, with the storm abating, InSight popped out of safe mode and called home, indicating power levels were potentially back to “normal” (e.g. running at around 25% of rated capacity). Even so, the mission team have opted to keep the science systems off-line until the storm had fully passed and an accurate assessment of the lander’s power situation can be made.

At the same time, and further south in Jezero Crater, the Mars 2020 mission was also impacted by a dust storm shortly after New Year’s Day. The rise in atmospheric dust was not a serious impediment to the nuclear-powered Perseverance rover, but it did cause worry among the Ingenuity helicopter team, because the tiny helicopter is solar powered, and has a very limited battery life that needs daily recharging. As such, there was concern that if the dust reached a point where minimal sunlight was reaching the helicopter’s little solar array, the battery might discharge faster than it could be charged up, killing the helicopter.

As it was, by January 5th, 2022, visibility within the crater was such that Ingenuity’s planned 19th flight had to be postponed. Not only did the use of its rotor mean a rapid depletion in battery reserves, the increased levels of dust lifted into the atmosphere during a storm acts as an insulating blanket, trapping sunlight and raising the ambient temperature and reducing its local density, which in turn makes it much harder for the helicopter to achieve lift.

Images acquired on January 9th, 2022 from the Mars Colour Imager instrument on NASA’s Mars Reconnaissance Orbiter are here combined to create a view of Mars showing the presence of a regional dust storm obscuring Jerzero Crater, home of the Mars 2020 mission(white circle). Credit: NASA/JPL / MSSS

In a way, the decision to postpone the January 5th flight marked another first for Ingenuity – making the first aircraft ever to have a flight delayed by inclement weather on another planet. But the decision was correct: on January 5th, atmospheric density in the area of the crater where both Perseverance and Ingenuity are located have dropped by 7% (as measured by the weather station on the rover), putting it below the minimum the helicopter required for stable flight, and Ingenuity’s solar array was gathering sunlight 18% below that recorded immediately prior to the storm arriving.

Mid-January saw the storm start to pass, and as it did so information returned by Ingenuity revealed it to be in good health, if in need of a little time in sunlight to restore itself. The 19th flight was therefore re-scheduled for Sunday, January 23rd, although at the time of writing this piece, there had been no news as to whether the planned 100 second flight had actually gone ahead.

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