Additional Artemis I test targets to build confidence in abilities – Parabolic Bow

Orion spacecraft orbiting the moon. (Credit: NASA)

NASA Mission Update

During Artemis I, NASA plans to accomplish several primary objectives, including demonstrating the performance of the Orion spacecraft’s heat shield from lunar return velocities, demonstrating operations and facilities during all phases of the mission, from launch countdown to recovery, and crew module recovery for post-flight. analysis. As the first integrated flight of the Space Launch System rocket, Orion spacecraft and ground exploration systems of the 21st Century Spaceport in Florida, engineers hope to accomplish a host of additional test objectives to better understand how the spacecraft performs in space and prepare for future crewed missions.

Accomplishing additional goals helps reduce risk for crewed missions and provides additional data for engineers to assess trends in spacecraft performance or improve confidence in spacecraft capabilities. Some of the additional objectives planned for Artemis I include:

Modal survey

On the service module built in Europe, Orion is equipped with 24 Reaction Control System (RCS) thrusters, small engines responsible for moving the spacecraft in different directions and rotating it. The Modal Survey is a prescribed series of small RCS shots that will help engineers ensure the structural margin of Orion’s solar array wings during the mission. The flight controllers will command several small engine firings to flex the gratings. They will measure the impact of the shots on the networks and assess whether the inertial measurement units used for navigation know what they should. Until the modal survey is complete, large translational burns are limited to 40 seconds.

Optical navigation camera certification

Orion has an advanced Guidance, Navigation and Control (GN&C) system, responsible for always knowing where the spacecraft is in space, which direction it is pointing and where it is going. It primarily uses two star trackers, sensitive cameras that take pictures of the star field around Orion, the Moon, and Earth, and compare the images to its built-in star map. The Optical Navigation Camera is a secondary camera that takes images of the Moon and Earth to help orient the spacecraft by looking at the size and position of celestial bodies in the image. Several times during the mission, the optical navigation camera will be tested to certify its use on future flights. Once certified, the camera can also help Orion return home autonomously should he lose communication with Earth.

Wi-Fi characterization of the solar generator wing camera

Cameras attached to the wingtips of the solar panels communicate with Orion’s camera controller via an integrated Wi-Fi network. The flight controllers will vary the positioning of the solar panels to test Wi-Fi strength while the panels are in different configurations. The test will allow engineers to optimize the speed with which images taken by cameras at the ends of networks can be transmitted to on-board recorders.

Crew module/service module surveys

Flight controllers will use the cameras on all four solar array wings to take detailed photos of the crew module and service module twice during the mission to identify any micrometeoroid impacts or orbital debris. A survey conducted at the start of the mission will provide images shortly after the spacecraft has flown past the altitude where the space junk resides and a second survey on the return journey will take place several days before reentry.

Large File Delivery Protocol Uplink

Mission control engineers will link large data files to Orion to better understand how long it takes the spacecraft to receive large files. During the mission, flight controllers use the Deep Space Network to communicate with the spacecraft and send data to it, but pre-flight testing does not include using the network. The test will help engineers understand if the spacecraft’s uplink and downlink capability is sufficient to support human validation of end-to-end communication ahead of Artemis II’s first flight with astronauts.

Star Tracker Thermal Rating

Engineers hope to characterize the alignment between star trackers that are part of the guidance, navigation and control system and Orion’s inertial measurement units, by exposing different areas of the spacecraft to the Sun and activating star trackers in different thermal states. The measurements will inform navigational state uncertainty due to thermal flexing and expansion that ultimately impacts the amount of propellant needed for spacecraft maneuvers during crewed missions.

Radiator Loop Flow Control

Two radiator loops on the spacecraft’s European service module help expel heat generated by various systems throughout the flight. There are two modes for the heaters. In speed mode, the radiator pumps run at a constant speed to help limit vibration and this is the primary mode used during Artemis I and during launch for all Artemis flights. Control mode allows better control of the radiator pumps and their flow, and will be used during crewed missions when more precise control of the flow through the radiators is desired. This objective will test the control mode to provide additional data on how it works in space.

Solar panel wing plume

Depending on the angle of the wings of Orion’s solar panels during certain thruster firings, the plume or exhaust from these firings could increase the temperature of the panels. Through a series of small RCS shots, engineers will collect data to characterize the heating of the solar panel wings.

Thruster Nerd

The liquid propellant stored in the spacecraft’s tanks moves differently in space than it does on Earth due to the absence of gravity in space. The motion of the thruster, or slosh, in space is difficult to model on Earth, so engineers plan to collect data on the motion of the thruster during several planned activities during the mission.

Search, Acquire, and Track (SAT) Mode

SAT mode is an algorithm intended to recover and maintain communications with Earth after Orion loses navigational state, prolonged loss of communications with Earth, or after a temporary power loss that requires Orion to restart equipment. To test the algorithm, flight controllers will order the spacecraft to enter SAT mode and, after about 15 minutes, restore normal communications. Testing SAT mode will give engineers confidence that it can be considered the final option for resolving a loss of communication when the crew is on board.

Aerothermal inlet

Upon entry of the spacecraft into Earth’s atmosphere, a prescribed series of 19 shots of the reaction control system on the crew module will be conducted to understand performance against projected data for the sequence. Engineers are interested in collecting this data during high heating on the spacecraft where aerothermal effects are greatest.

Built-in satellite-assisted search and rescue (SARSAT) functionality

The SARSAT test will verify the connectivity between the beacons that will be carried by the crew on future flights and the ground stations receiving the signal. The beacons will be activated and powered remotely for approximately one hour after the splash and will also help engineers understand if the transmitted signal is interfering with communications equipment used during recovery operations, including the built-in tri-band beacon of ‘Orion which transmits the precise location of the spacecraft after the splashdown. .

Restarting the ammonia boiler

After Artemis I is splashed, Orion’s Ammonia Boiler will be shut down for several minutes and then restarted to provide additional system capacity data. Ammonia boilers are used to help control the thermal aspects of the spacecraft to keep its power and avionics systems cool, and to keep the interior of the crew module at a comfortable temperature for future crews . In some potential emergency landing scenarios for crewed missions, crews may need to turn off the ammonia boiler to check for hazards outside the spacecraft, then possibly turn it back on to provide additional cooling .

Engineers will perform additional testing to gather data, including monitoring the heat shield and interior components for post-splash saltwater intrusion. They will also test the GPS receiver on the spacecraft to determine the spacecraft’s ability to pick up the transmitted signal around the Earth, which could be used to increase the spacecraft’s ability to understand its positioning if it loses communication with it. mission controllers.

Collectively, completing additional goals during flight provides additional information that engineers can use to improve Orion as the NASA spacecraft that will take humans to deep space for years to come.

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