On Wednesday April 1st, 2026, NASA’s Artemis 2 mission launched on a 10-day cruise to the Moon and back (with time initially spent in Earth orbit), carrying a crew of four to test the capabilities and facilities of the Orion Multi-Purpose Crew Vehicle (MPCV) when used for human spaceflight.
The mission marks a number of firsts for NASA, all critical to future Artemis missions, including:
- The first launch of a Space Launch system (SLS) rocket with a crew aboard.
- The first launch of the Orion spacecraft – this one christened Integrity by its crew – with people aboard.
- The first time an Orion spacecraft has flown under manual control.
- The first time an Orion vehicle will attempt a re-entry into Earth’s atmosphere carrying a crew aboard.
- The first time humans have surpassed 400,000 kilometres from Earth.
- The first time a vehicle intended for use in the vicinity of the Moon has carried an actual toilet on board.
- The first time a non-US citizen has travelled to the Moon.
The four crew in question are Mission Commander Reid Wiseman, Mission Pilot Victor Glover, Mission specialist Christina Koch (pronounced “Cook”), all from NASA, and Mission Specialist Jeremy Hansen of the Canadian Space Agency. If you’re interested in potted histories of the crew’s backgrounds, then please refer to my previous Space Sunday article.
Launch
Lift-off came at 22:35 UTC, some 11 minutes later than the target launch time after a couple of minor issues on the SLS vehicle had to be investigated and resolved. One of these related to one of the two battery systems powering the Flight Termination System. The latter is used to destruct the rocket once the crew have been pulled clear by the Launch Abort System (LAS), should a serious issue result in the rocket veering substantially off-course. This particular problem was identified as a sensor failure rather than any fault with the battery itself.
The power of the SLS was immediately apparent following launch – at just thirty seconds into the flight, the launch system has completed its roll to pitch over to the correct ascent angle and was punching through 4.8 kilometres altitude as a speed in excess of 1,920 km/h. From there:
- At T+1 minute the vehicle passed through ”Max Q”, the period when the rocket encounters the peak atmospheric dynamic stresses as it continues to accelerate through the denser portion of the atmosphere, the four RS-25 motors of the core stage throttling back to reduce the load on the rocket.
- At T+ 90 seconds, with Max Q passed and the RS-25 motors running at 100% thrust, the SLS went supersonic and passing through 22.4 km altitude.
- At T+2 minutes, with the RS-25 motors had again throttled to 85% thrust, and the two massive solid rocket boosters, their fuel expended, separated to continue on their own ballistic trajectory, eventually falling into the Atlantic Ocean.
- By 3 minutes into the ascent, Artemis 2 was at 78.4 km altitude, and closing on the 80 km Kármán line, the conventional definition of “the edge of space”. Travelling at some 8,000 km/h, the rocket jettisoned the two fairings that had protected Integrity’s European Service Module (ESM).
- This was followed almost immediately by the unlocking of the couplings between the LAS at the top of the rocket, and the Orion capsule. The motors on the LAS fired, pulling it clear of the SLS, exposing the Orion capsule to space.
- MECO – main engine cut-off – occurred at 8 minutes 2 seconds after lift-off, with Integrity and the Interim Cryogenic Propulsion Stage (ICPS) continuing to ascend, the reaction control systems (RCS) on the ICPS sufficient to pull it and Integrity clear of the SLS core stage, which, like the SRBs, continued on its own ballistic trajectory, prior to starting a long fall back to Earth, breaking up in the process and falling into the Atlantic Ocean.
At this point, Integrity was travelling at 27,200 km/h – slightly above the speed required to achieve Earth orbit and on a trajectory intended to put it into an elliptical orbit around Earth with a perigee (closest point to Earth) of around 200 km. At this point, operations switched from launch to initial mission activities.
The latter comprised two major elements: inside the Orion capsule, Christina Koch and Jeremy Hansen left their seats to set-up critical equipment and services. These included unstowing the fire-fighting equipment and mounting it on its assigned racks and then doing the same with the drinking water dispenser, toilet (which had its first malfunction, requiring Koch and Hansen to carry out a fix (the Toilet would again have issues on Flight Day 4, with the crew reporting it was depositing unpleasant odours in the main capsule) and other crew-related equipment. At the same time, Wiseman and Glover remained in their seats and ran through the protocols and check sheets for deploying the ESM’s solar arrays – vital for supplying Integrity with electrical power.
The solar arrays were deployed some 25 minutes after launch, and powered-up to start producing electrical power. At 50 minutes after lift-off, Hansen and Koch were back in their seats, the solar arrays were producing power and the go was given for two orbit-changing manoeuvres.
The first was a short burst of the ICPS RL-10 engine, raising the perigee of Integrity’s orbit whilst maintaining its elliptical form. This was followed by a second 15-minute burn of the RL-10, extending Integrity’s perigee and apogee (the latter to some 70,000 km from Earth, placing the vehicle in a high Earth orbit.
This second RL-10 burn expended almost all remaining fuel in the ICPS, accelerating Integrity almost to the velocity required to complete a trans-lunar injection (TLI) manoeuvre. However, this is not what happened. Instead, with the ICPS separated and orbiting Earth independently of Integrity, Glover and Wiseman commenced what NASA normally refers to as an RPOD simulation, but which for Artemis 2 was simply called “proximity operations”.
RPOD Simulations / Proximity Operations
RPOD – Rendezvous, Proximity Operations and Docking – is a core part of modern day space operations with NASA, being fundamental to crews and supplies being able to launch to and reach the International Space Station (ISS) and then dock safety with it either under automated or manual control.
For the Artemis programme, being able to carry out a successful RPOD is vital to all the lunar surface missions, as they must be able to rendezvous and temporarily dock with the Moon- orbiting Human Landing System (HLS) vehicle which will actually deliver nominated crew members to the surface of the Moon, and then re-dock with the HLS vehicle to allow the surface mission crew return to their Orion craft for a return to Earth.
To this end, the ICPS had been equipped with a rendezvous and docking target, allowing Wiseman and Glover to test out the docking heads-up display whilst also using Integrity’s RCS thrusters to make simulated rendezvous approaches to the ICPS, aborting before the two vehicles actually made contact. In addition, Wiseman and Glover used manual control of the Orion to test proximity manoeuvring and close formation flying around the ICPS – both the POD and proximity operations marking the first time Orion had ever been manually flown. Both astronauts praised the vehicle’s handling qualities prior to returning the craft to its autopilot.
With Integrity well clear of the ICPS, the latter deployed two CubeSats then fired its RL-10 for a final time, placing it on a destructive re-entry into the upper atmosphere. At this point the crew moved to the next phases of initial operations.
Initial Mission Highlights
First, the Orion’s “gymnasium” – a flywheel device capable of allowing multiple exercises – was set-up and crew members took it in turns exercising, putting Integrity’s life support system through something of a stress test. After this, the crew set-up the food reheater and had dinner together from their rather impressive menu of meal choices. A 4-hour sleep period was then taken, allowing the crew some much needed rest.
The sleep period was short as a further orbital manoeuvre was required to again raise Integrity’s perigee away from Earth and place it on a trajectory suitable for a TLI burn. With this complete, the crew settled back for another 4-hour sleep period whilst NASA mission control reviewed the overall performance of Orion and its systems to determine if Integrity was good to go for a free-return flight for the Moon.
Authorisation was given for TLI on flight day 2 after the crew had risen and eaten. The manoeuvre comprised a burn of the ESM’s AJ10 main engine of just under 6 minutes, using some 450 kg of hypergolic propellants. It pushed Integrity out of Earth’s orbit and on its way to pass around the Moon. This free return trajectory meant the vehicle would not need to use its AJ10 engine as it passed around the Moon in order to head back to Earth – gravity would do the work for the mission. However, the ESM’s propulsion systems would be required for various mid-course correction manoeuvres.
The first of these course corrections was due on Flight Day 3. However, such was the accuracy of the SLS’s performance coupled with that of Integrity itself, this manoeuvre was discarded – the vehicle was precisely on the course it needed. On Flight Day 4 Hansen (a Canadian fighter pilot) and Koch (a jet-qualified civilian pilot) took the controls of Orion and put the vehicle through a further series of RCS tests, evaluating its ability to complete both 3- and 6-degrees of freedom of movement manoeuvres (that is, rolling, pitching and yawing around various axes without altering its general trajectory). Both Koch and Hansen reported the vehicle presented excellent and stable handling.
Currently, the crew is due to pass around the Moon on Monday, April 6th. 2026 as they do so, they will reach a distance of approximately 406,773 kilometres from Earth, beating the previous record for the furthest humans have travelled from Earth to date – set by the abortive Apollo 13 mission in 1970 – by some 6,000 km. At this point, Integrity will be some 7,600 km beyond the surface of the Moon’s far side as it starts its journey home. The closest Artemis 2 will come to the surface of the Moon is approximately 6,513 km.
During the intervening period, the crew continue to test Integrity’s systems and capabilities and carry out a range of experiments, notably related to crew health and welfare. As a part of this work, Integrity carries two key experiments: AVATAR – A Virtual Astronaut Tissue Analogue Response, and an experiment system called ARCHeR (Artemis Research for Crew Health & Readiness (if there is one thing you definitely can say about NASA is that they work very hard at their acronyms!)
AVATAR can mimic individual astronaut organs, allowing medical experts evaluate tissue and other responses to various aspects of spaceflight and monitor essential biomarkers. AVATAR has been flown aboard the ISS several times, but this mission marks its first deep space mission – one that carries it and the Artemis 2 crew through the Van Allen radiation belts – thus offering the opportunity to gain further insight into the potential impact of these highly radioactive zones as Integrity zooms through them at several thousand km/h.
ARCHeR (which I cannot help think was named by an NASA fan of Star Trek (see Jonathan Archer (Scott Bakula), first commander of the Star Ship Enterprise, NX01) uses movement and sleep monitors worn by the crew to gather real-time health and behavioural information for crew members so scientists can study sleep patterns and overall health performance.
Further, Artemis 2 is testing and demonstrating the Orion Artemis II Optical Communications System (O2O). This is an optical communications system uses laser beams for two-way communications between Earth and the mission. Smaller and lighter than a conventional radio system, O2O also uses less power and increases transmission rates (up to 200 Mbits per second). If successful, O2O could become a feature of future Artemis missions from Artemis 4 onwards and used in potential human missions to Mars.
I’ll have more on Artemis 2 next week. In the meantime, you can follow the mission in real-time, via NASA’s 24/7 livestream.
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