NASA Just Completed The Full Artemis I Mission Review
Almost four months ago in the middle of November, the Space Launch System lifted off for the first time ever. Over the next few weeks, the rocket, Orion, and various systems would go on to complete over a hundred tests before returning to Earth with a successful splashdown. All this being said, while on the surface the mission went great, not everything went fully according to plan.
The heat shield of Orion for example, an immensely important component, did not perform as expected with reports of excessive material being lost. Something the agency is focusing on with Artemis II scheduled not long from now with humans. They also shared more information on the damage to the ground systems and launch tower. On the other hand, they confirmed that other valuable systems outperformed their expectations.
Right now NASA is trying to prepare for the next mission scheduled to happen in 2024. Based on the results of this initial mission, they confirmed that they are still on track for that launch date. Here I will go more in-depth into Orion’s heat shield concerns, the overall system performance, what to expect in the coming months, and more.
Orion’s Heat Shield
Right now, teams at NASA are reviewing more than 155 gigabytes of Orion data to confirm the spacecraft’s performance. Starting with the concerns, NASA is more closely examining data for two observations from the flight. For one, engineers noted variations across the appearance of Orion’s heat shield in which the ablative material that helps protect the capsule from the extreme heat of reentry wore away differently than predicted. On March 7th, during a NASA teleconference, the manager of NASA’s Orion Program said, “Some of the expected char material that we would expect coming back home ablated away differently than what our computer models and what our ground testing predicted. So we had more liberation of the charred material during reentry before we landed than we had expected.” He went on to say, “Overall, there’s a lot of work to be done in this investigation going forward. We are just starting that effort because we’ve just gotten together all those pieces of information. Those samples, the videos, images, and the data from the spacecraft itself and correlated them together. And now we’re assessing that data and moving forward with that assessment.”
NASA made it clear that post-flight inspection showed a significant amount of original Avcoat material remained on Orion. Thermal protection system experts have correlated the timing of descent through the atmosphere with data from hundreds of sensors as well as gathered imagery and video. With this in mind, teams are assessing this set of data to understand the phenomenon. Despite the unexpected loss and irregular charring of heat shield material during reentry, NASA’s program managers stressed that they feel confident that the crewed Artemis 2 mission will be able to launch on schedule in 2024.
Not only did the heat shield bring up some concerns, but experts also continue to assess an issue seen during the flight where latching current limiters switched open without commanding several times throughout the mission. These switches, which are circuit breaker-like devices that are part of a power conditioning and distribution unit responsible for taking power generated by the solar arrays and preparing it for distribution to systems, help control power to components in the service module. Engineers are reviewing flight data to understand the source of the issue and plan to conduct testing in a flight-like configuration.
On the bright side, data shows the European-built service module generated 20% more power than initial expectations and consumed about 25% less power than predicted. All the spacecraft’s dynamic separation events, such as separation of the launch abort system during ascent and parachute deployment during landing — which involved 375 pyrotechnic devices total — were completed without issue. Splashdown, which was moved 300 miles south due to poor weather, occurred 2.4 miles from the target landing spot, which is still well within requirements. Upon return to Kennedy Space Center in Florida, avionics components earmarked for reuse on Artemis II were removed and refurbished for integration, including phased array antennas, a vision processing unit, GPS receivers, and inertial measurement units. All Artemis I avionics components have been integrated into the Artemis II crew module.
SLS Performance & Future
Orion was not the only important piece in the Artemis I launch, the Space Launch System and ground systems for example also were put under review. NASA’s official report highlighted, “Both initial and more comprehensive analysis of the SLS rocket’s debut flight show the rocket flew as designed and with precision, with all of its systems meeting, and in many cases exceeding, performance expectations.” Following a near-perfect trans-lunar injection burn, the rocket’s interim cryogenic propulsion stage and Orion successfully separated, delivering Orion to its initial target orbit and then on a trajectory toward the Moon.
On the ground, engineers with NASA’s Exploration Ground Systems program completed detailed assessments of the mobile launcher shortly after launch. Although the launcher sustained more damage than initially expected from the 8.8 million pounds of thrust generated at liftoff by the rocket, work already is underway to repair damaged components in tandem with planned upgrades in preparation for Artemis II, the first flight with astronauts that will send the crew. Mobile launcher damage included corrosion to pneumatic, or air-filled, and cryogenic fueling lines, detached welds on tubing, approximately 60 broken panels and cabinets with instrumentation, and destruction to several elevators and blast shields, which are currently being repaired. They commented that modifications to the mobile launcher to support future Artemis missions are underway and on track, including incorporating elements to support an emergency egress systems at the launch pad.
While work is underway to understand every issue, NASA is making progress assembling, testing, and processing the elements for Artemis II ahead of the late 2024 mission. The heat shield will be attached to the crew module in May, and the crew module and service module will then be connected ahead of integrated testing. The SLS solid rocket booster motor segments and core stage will be shipped to Kennedy later this year, after the engine section and RS-25 engines are connected to the rest of the already-complete stage. Teams expect to transport the mobile launcher to launch pad 39B this summer for testing, including evaluation of the emergency egress capability needed for Artemis II. The recovery team, along with personnel from the Department of Defense, recently completed rigorous testing of a new crew module test article in support of Artemis II efforts and will conduct open water recovery testing in the coming months to ensure the crew on board are quickly and safely removed from the spacecraft. All steps toward a milestone mission for the rocket and agency.
On Artemis II, the mission will launch a crew of four astronauts from NASA’s Kennedy Space Center in Florida on a Block 1 configuration of the Space Launch System (SLS) rocket. The flight profile is called a hybrid free return trajectory. Orion will perform multiple maneuvers to raise its orbit around Earth and eventually place the crew on a lunar free return trajectory in which Earth’s gravity will naturally pull Orion back home after flying by the Moon. After the burn to enter high-Earth orbit, Orion will separate from the ICPS. The expended stage will have one final use before it is disposed through Earth’s atmosphere—the crew will use it as a target for a proximity operations demonstration. While still close to Earth, the crew will assess the performance of the life support systems necessary to generate breathable air and remove the carbon dioxide and water vapor produced when the astronauts breathe, talk, or exercise.
After completing checkout procedures, Orion will perform the next propulsion move, called the translunar injection (TLI) burn. With the ICPS having done most of the work to put Orion into a high-Earth orbit, the service module will provide the last push needed to put Orion on a path toward the Moon. The TLI burn will send crew on an outbound trip of about four days and around the backside of the moon where they will ultimately create a figure eight extending over 230,000 miles from Earth before Orion returns home. The Artemis II crew will travel 6,400 miles beyond the far side of the Moon. From this vantage point, they will be able to see the Earth and the Moon from Orion’s windows, with the Moon close in the foreground and the Earth nearly a quarter-million miles in the background.
With a return trip of about four days, the mission is expected to last just over 10 days. Instead of requiring propulsion on the return, this fuel-efficient trajectory harnesses the Earth-Moon gravity field, ensuring that—after its trip around the far side of the Moon—Orion will be pulled back naturally by Earth’s gravity for the free return portion of the mission. If successful, NASA’s next mission will be Artemis III, where humans will once again step foot on the Moon.
Conclusion
NASA just completed an initial review of the main systems apart of the Artemis I launch. They revealed some concerns regarding Orion’s heat shield and the extent of damage to the various ground systems. They also reported a lot of promising results regarding the rocket, European Service Module, and more. We will have to wait and see how it progresses and the impact it has on the space industry.