NASA’s upcoming Artemis I mission represents a critical milestone on the space agency’s path towards establishing a sustainable human presence on the Moon. It will mark not only the first flight of the massive Space Launch System (SLS) and its Interim Cryogenic Propulsion Stage (ICPS), but will also test the ability of the 25 ton Orion Multi-Purpose Crew Vehicle (MPCV) to operate in lunar orbit. While there won’t be any crew aboard this flight, it will serve as a dress rehearsal for the Artemis II mission — which will see humans travel beyond low Earth orbit for the first time since the Apollo program ended in 1972.
As the SLS was designed to lift a fully loaded and crewed Orion capsule, the towering rocket and the ISPS are being considerably underutilized for this test flight. With so much excess payload capacity available, Artemis I is in the unique position of being able to carry a number of secondary payloads into cislunar space without making any changes to the overall mission or flight trajectory.
NASA has selected ten CubeSats to hitch a ride into space aboard Artemis I, which will test out new technologies and conduct deep space research. These secondary payloads are officially deemed “High Risk, High Reward”, with their success far from guaranteed. But should they complete their individual missions, they may well help shape the future of lunar exploration.
With Artemis I potentially just days away from liftoff, let’s take a look at a few of these secondary payloads and how they’ll be deployed without endangering the primary mission of getting Orion to the Moon.
Flying Economy Class
Ultimately, the goal of Artemis I is to demonstrate that the Orion capsule can enter lunar orbit, navigate and maneuver while near the Moon, and then safely return to Earth. Should this test fail, it will undoubtedly delay future Artemis missions, and could even put the plans for a human landing in jeopardy. For NASA’s long-term goals, it’s absolutely critical that this mission is a success.
The CubeSats along for the ride are in no way, shape, or form, a priority for NASA or Mission Control. While everyone would like to see them succeed, no special treatment or consideration will be given to these craft. If a decision needs to be made that will save the Orion at the expense of the secondary payloads, there’s no question which way it will go.
To prevent any possible interaction with the primary mission, the CubeSats won’t even be deployed until nearly two hours after Orion has separated from the ICPS. Once the capsule has moved a safe distance away, the small satellites will be sequentially released from angled dispensers mounted to the inside of the stage adapter.
The stage adapter includes a dedicated avionics package that is isolated from the primary mission electronics, and is responsible for determining when each spring-loaded dispenser is to activate and push out its respective CubeSat. A power bus was provided to charge the 18560 cells used in the CubeSats, but for safety, it is also isolated from the SLS’s own electrical system.
Unfortunately, that means the last time the CubeSats were charged was before the Orion spacecraft was mounted to the adapter in the Vehicle Assembly Building (VAB) back in October 2021. To further complicate matters, the status of each individual craft is currently unknown, as NASA requires the satellites to be powered-down until 15 seconds after their release from the stage adapter.
After sitting for nearly a year, there’s a very real possibility that the batteries in some of the satellites might have become depleted. In that case, the craft’s onboard photovoltaic cells will hopefully be able to recharge them once deployed. If not…at least the ride to space was free.
Research Worth the Risk
Riding to space on an untested rocket is already risky enough, but when you’re flying your satellite as the secondary payload on a prototype rocket without even knowing if its batteries are charged, that’s really rolling the dice. Given the odds, you might assume that the CubeSats would have simplistic missions — after all, why would researchers invest valuable time and material into such an uncertain proposition? But that ignores the one-in-a-career siren’s call of being offered a free trip to the Moon.
As it so happens, there’s some very interesting science crammed into those secondary payload dispensers, with several experiments representing the first of their kind. Here are just a few of the highlights:
Perhaps the most ambitious of the secondary payload missions is the Outstanding MOon exploration TEchnologies demonstrated by NAno Semi-Hard Impactor (OMOTENASHI) built by the Japan Aerospace Exploration Agency (JAXA). This CubeSat will follow Orion all the way to the Moon, and use its thrusters to put itself on a collision course with the lunar surface. When the onboard radar determines it’s at the appropriate altitude, a solid rocket motor will ignite to decelerate the landing module, which will then free-fall some 100 meters (328 feet) to the surface. Just before touchdown, a 50 cm (1.6 foot) airbag will inflate to cushion the impact.
If everything goes according to plan, OMOTENASHI (which translates to “welcome” or “hospitality” in Japanese) will be by far the smallest vehicle to make a controlled landing on the lunar surface. While the mission is primarily designed to test the landing technique, the lander does have an accelerometer and UHF transmitter onboard that will hopefully return useful data should the 0.7 kg (1.5 lb) craft survive its close encounter with the lunar regolith.
As an interesting aside, the team behind OMOTENASHI has challenged the community to detect its telemetry signals both during its flight to the Moon and after it’s touched down on the surface. In the event that any Hackaday readers manage to pick it up, we’d love to hear about it.
The Italian ArgoMoon mission will demonstrate the techniques necessary for a CubeSat to maneuver in close proximity to another spacecraft, using the ICPS itself as the target. Once dispensed the satellite will fly in close formation with the ICPS, and will use its onboard cameras to photograph the SLS upper stage for historical purposes.
As ArgoMoon is scheduled to be one of the first secondary payloads to be released, it will also have the opportunity to record the deployment of several other CubeSats. Due to the limited instrumentation of the dispensers, imagery from the craft will be used to determine if all of the satellites have been successfully deployed.
Eventually, ArgoMoon will use its onboard thrusters to move away from the ICPS and put itself into a high-altitude orbit above the Earth. During the following months, the craft will be exposed to the sort of deep space conditions that traditionally CubeSats avoid by staying within the confines of Earth’s magnetic field. This time will be used to validate the radiation-hardened components developed by ArgoMoon’s manufacturer, Argotec.
While Orion and several of the secondary payloads are headed to the Moon, the NEA Scout will be setting course for a different target: 2020 GE, a near-Earth asteroid (NEA) with a diameter of less than 18 meters (60 feet). While the CubeSat has thrusters for orienting itself, its primary means of propulsion will be a 86 square meter (925 square foot) solar sail. It will be unfurled between four extendable booms, using a mechanism derived from the one used in the Planetary Society’s LightSail spacecraft.
After a lunar gravity assist, NEA Scout will be on course to intercept 2020 GE in late 2023. The craft will get within 1.6 km (1 mile) of the asteroid, and perform what mission planners believe will be the slowest flyby in the history of space exploration, passing it at a relative speed of just 30 meters (100 feet) per second. This will give NEA Scout hours to image the asteroid with its camera and sensors, making it the first time such a small object has ever been directly observed from a free-flying spacecraft.
The mission will not only be another important step in the development of solar sail technology, but the data collected from 2020 GE will help inform future planetary defense systems. Currently scientists don’t know if NEAs of this scale are actually solid objects or a loose mass of small rocks and dust, and it’s hoped the results of this up-close study will allow scientists to come up with plans to destroy or deflect similar objects if need be.
One for the History Books
While they may differ in scale and complexity, all of the secondary payloads on Artemis I promise to deliver exciting new science. The LunaH-Map, developed by Arizona State University, will attempt to create a detailed map of water deposits on the Moon’s surface which could greatly benefit future human exploration. BioSentinel will be the first long-duration biology study outside of low Earth orbit, and will study the impact of space radiation on DNA. Pick any mission from the list, and you’ll find yourself falling down a fascinating rabbit hole.
Over the years, much has been said about the enormous cost of the Space Launch System, which at this point has been in development for over a decade. Many argue that it’s a relic of “Old Space” mentality, and that new and more agile rockets from SpaceX and Blue Origin will make it obsolete before it’s even flown more than a handful of times. Only time will tell if those criticisms are valid, but the incredible scientific potential of this inaugural flight seems a clear indicator that at the very least, NASA intends to get their money’s worth out of their brand-new megarocket.