Artemis II launch opportunities announced
On , the Space Launch System (SLS) rocket and the Orion spacecraft lifted off from NASA's Kennedy Space Center as part of the Artemis I mission. (Credit: NASA/Bill Ingalls)
NASA has released the potential launch dates and times for the Artemis II mission. The next opportunity opens up on (ET) for a window of two hours.
Previously announced potential launch dates have been removed following updates from NASA.
| Date | Window opens (ET) | Coordinated Universal Time (UTC) date and time | Window duration (minutes) | Lighting/darkness |
|---|---|---|---|---|
| March | ||||
| 120 | 2.05 hours after sunset | |||
| 120 | 2.51 hours after sunset | |||
| 120 | 3.48 hours after sunset | |||
| 120 | 4.40 hours after sunset | |||
| 115 | 5.36 hours after sunset | |||
| April | ||||
| 120 | 1.28 hours before sunset | |||
| 120 | 0.30 hours after sunset | |||
| 120 | 1.17 hours after sunset | |||
| 120 | 1.95 hours after sunset | |||
| 120 | 2.87 hours after sunset | |||
| 120 | 1.86 hours before sunset | |||
What are launch windows exactly?
Launch windows are specific time periods during which a launch must occur to achieve the desired orbit or reach a specific destination.
How are the launch windows determined?
These windows are determined by the positions of Earth and the target of the spacecraft relative to each other (the Moon, in the case of Artemis II).
Launch windows account for the complex orbital mechanics involved in launching on a precise trajectory toward the Moon while Earth is rotating on its axis and the Moon is orbiting Earth each month in its lunar cycle.
- The launch day and time must allow SLS to be able to deliver Orion into a high Earth orbit where the crew and ground teams will evaluate the spacecraft's life support systems before the crew ventures to the Moon.
- Orion must be in the proper alignment with Earth and the Moon at the time of the translunar injection burn. This burn places Orion on course to fly by the Moon and also sets it on a free return trajectory, in which the spacecraft uses the Moon's gravity to send itself back to Earth without additional major propulsive manoeuvres.
- The trajectory for a given day must ensure Orion is not in darkness for more than 90 minutes at a time so that the solar array wings can receive and convert sunlight to electricity, and the spacecraft can maintain an optimal temperature range.
How long are launch windows?
Launch windows can be as short as a few minutes, so the launch must be timed precisely. For Artemis II, all launch windows, except one on , last two hours. The first launch attempts are normally done at the beginning of a window, but technical issues and weather can cause launches to be delayed to later within the launch window or to another launch window altogether. These delays are common.
Because Artemis II is the first crewed flight test of the Artemis campaign, running into a few issues that could cause delays is probable. The uncrewed Artemis I mission, for example, was delayed three times – twice for technical issues (a faulty engine temperature reading and later a hydrogen leak during fuelling) and another time due to bad weather – before launching in .
All updates of the date and time of the launch will be shared on the Canadian Space Agency's social media accounts and Website.
What time zone will the mission follow?
Artemis II will launch from Florida (Eastern time) and splash down off the coast of San Diego (Pacific time), but the crew and the ground teams will work in Mission Elapsed Time (MET). This is meant to avoid the constant rescheduling of tasks in case the launch slips.
MET is the amount of time recorded starting at the launch of a spacecraft (zero) and counts forward in normal days, hours, minutes, and seconds.
Fun fact
MET has been used for many missions, including the past missions of the Space Shuttle era. The International Space Station (ISS), however, does not use MET since it is a permanent and international mission. It uses UTC, which is about halfway between the United States and Russia, the main partners of the ISS.