(WKBN) – Space enthusiasts were all abuzz over the launch of NASA’s Artemis I launch earlier this month and what that could mean for the future of space exploration. The goal of the mission is to test the next age of spacecraft aimed to take humans into space. The first attempted launch had to be scrubbed after equipment malfunctions. NASA announced late last week that repairs have been made and they are on target to attempt a launch in the next window of dates later this month. Should this mission go successfully, NASA would remain on track to send humans to the moon again in 2025.

Why are there specific windows of time when the launch is possible?

There are a lot of new technologies being tested in this mission, and a lot of precise measurements and calculations that have been done to ensure success. The mission will be testing NASA’s new rocket, called the Space Launch System (SLS). NASA describes it as the world’s “most powerful rocket” saying it is capable of carrying “more payload to deep space than any other vehicle.”

The mission will also test the next generation of “space capsule,” the Orion. NASA says the new vehicle will serve as the vessel carrying humans to space for exploration and “provide emergency abort capability, sustain astronauts during their missions and provide safe re-entry from deep space return velocities.”

Map of the Artemis I flight plan. NASA says the Artemis I mission is the “first in a series of increasingly complex missions, Artemis I will be an uncrewed flight that will provide a foundation for human deep space exploration, and demonstrate our commitment and capability to extend human existence to the Moon and beyond. During this flight, the uncrewed Orion spacecraft will launch on the most powerful rocket in the world and travel thousands of miles beyond the Moon, farther than any spacecraft built for humans has ever flown, over the course of about a three-week mission.”

So why are there only specific windows when a launch can happen? It has to do with all the “stars” that need to “align” perfectly for success. In less vague terms, the rocket can launch at any time but the moon needs to be correctly positioned in its orbit to capture the Orion space vessel in the moon’s gravitational pull after the upper chamber of the new rocket propels the capsule in that direction.

The SLS rocket launching the Orion vessel has plenty of power to take Orion to what’s called Lower Earth Orbit. But a lot more power is needed to carry the capsule to the moon. That is where the upper part of the rocket comes into play. The upper part of the rocket is equipped with a secondary propulsion system. The maneuver using this system is being called a “trans-lunar injection” and will use the upper part of the rocket known as the “interim cryogenic propulsion stage” of the rocket to push the vessel toward the moon. According to NASA, when engaged, the force of this engine will exert 24,750 pounds of thrust and propel the vessel at speeds of more than 22,600 miles per hour. At that speed, the vessel will be able to escape the gravitational pull of the earth. It will be hurled toward the moon with a precise track that will allow the vessel to reach the point where the force of the moon’s gravitational pull intercepts Orion.

The Space Launch System rocket reaches Lower Earth Orbit with the power of two solid rocket boosters and a core stage with four RS-25 engines. From here, the interim cryogenic propulsion stage fires its RL10 engine to send the uncrewed Orion to the moon for Artemis 1. Credits: NASA/MSFC

It takes a rocket scientist to make all the calculations needed to make that happen, and that isn’t even half of what goes into the variables impacting launch. Another key variable, once the Orion vessel is propelled toward the moon, is the fact that the Orion vessel can’t go more than 90 minutes at a time without sunlight. Orion is a solar-powered space vehicle and the “solar array wings” of the vessel convert sunlight into energy. That energy will be used to “maintain an optimal temperature range,” according to NASA.

NASA animation of the Orion vessel. Courtesy: NASA

The next variable that goes into this involves the reentry of Orion when it returns to earth. NASA now has the technology and capabilities to employ what is called a “skip entry” when the vessel returns. So what does that mean? Basically, the vessel will skip like a rock in the upper atmosphere of the earth as it returns from the voyage. NASA says Orion will use the upper atmosphere and “lift from the capsule” to bounce back out of the atmosphere before reentering for the final descent to the earth’s surface. There are a couple different reasons for doing this. First, NASA says this will give a much more accurate location for where the capsule will land and allows for landings much closer and more targeted with the U.S. coast. Second, it will lower the g-forces astronauts experience as the vessel reenters.

The last variable that goes into the launch will be conditions at the surface when Orion splashes down. NASA wants daylight conditions when Orion makes contact with the Pacific Ocean. This makes it easier to locate and retrieve the vessel.

All of these variables are going into the calculations for different launch windows throughout the remainder of the year. Because of the number of criteria needing to be met, certain windows will correspond with a shorter duration of the mission, between 26 to 28 days, or longer duration of the mission, between 38 to 42 days.

What other variables can impact the rocket launch date?

Once a launch date is chosen and the final preparations are made, there are implications to future launch dates in the given window if the first attempt is scrubbed. A lot of it has to do with the infrastructure at the Kennedy Space Center and the fuel being used in the new SLS rocket. NASA says storage tanks located at the launch site hold liquid oxygen and hydrogen that are loaded into the rocket’s main core and upper core. If the first attempt doesn’t happen, NASA says it is a minimum of 48 hours before the next attempt can be made. If that second attempt is called off, it will be another 72 hours before a third attempt can occur. The reason for the longer delay is the need to resupply the fuel tanks. This means that in any seven-day launch window, a total of only three attempts can be made.

Components of the SLS rocket to be used in the Artemis I launch, configured with the Orion vessel at the top. Courtesy: NASA

When is the next window for NASA’s Artemis I to launch?

NASA is preparing to make another launch attempt at the end of Sept. 2022. The Sept. 3 attempted launch was canceled after a liquid hydrogen leak was detected. NASA reported Friday, Sept. 9 that the seals where the leak originated have been replaced. The next step will be to test these seals. Hydrogen doesn’t exist in a liquid state at temperatures above -423°F so using liquid hydrogen requires extremely cold conditions. NASA plans to test the replaced seals under the super-cooled conditions no earlier than Sept. 21.

Assuming that fuel test goes well, NASA announced Monday that preparations are underway to attempt the next launch on Tuesday, Sept. 27. The window for launch begins at 11:37 a.m. and lasts for 70 minutes. If this were the date of the launch, the mission would fall under the long duration timeline. The return date for the vessel would be Saturday, Nov. 5. With this date, Orion would be in space for 39 days.

NASA reported Monday that a backup launch for Sunday, Oct. 2 is currently under review. There is a 109-minute window for launch on Oct. 2 that begins at 2:52 p.m. If this were to be the launch date, it would fall under the long duration timeline. The return date for the vessel would be 40 days later on Friday, Nov. 11.

What happens if the Artemis I mission can’t launch on either of those dates?

Should the launch windows on Sept. 27 and Oct. 2 not work out, NASA could attempt another launch on Tuesday, Oct. 4. They can only make a total of three attempted launches in a seven-day window.

After Oct. 4, the next window to launch isn’t until later in the month. The next grouping of days would be between Oct. 17-31. An exception would be Oct. 24, 25, 26 and 28. Launches can’t happen on those days because there would be windows where the Orion vessel would be shielded from the sun for greater than 90 minutes during the journey if the launch occurred on those dates.

The following is a list of launch opportunities, updated August 2022, through summer 2023 and how many opportunities there are in each stretch of days to launch:

October 17, 2022 – October 31, 2022 (11 opportunities for launch)
November 12, 2022 – November 27, 2022 (12 opportunities for launch)
December 09, 2022 – December 23, 2022 (11 opportunities for launch)
January 06, 2023 – January 20, 2023 (10 opportunities for launch)
February 02, 2023 – February 17, 2023 (14 opportunities for launch)
March 01, 2023 – March 17, 2023 (16 opportunities for launch)
March 29, 2023 – April 13, 2023 (12 opportunities for launch)
April 25, 2023 – May 10, 2023 (14 opportunities for launch)
May 22, 2023 – June 06, 2023 (11 opportunities for launch)
June 20, 2023 – July 02, 2023 (10 opportunities for launch)

The detailed calendar from NASA that includes the list of dates in each of those windows where a launch can’t occur due to lack of sufficient sunlight on the Orion trajectory can be found on this PDF file on NASA’s website.

Below is a video from NASA outlining what all will happen through the duration of the Artemis I mission after the launch finally takes place.

NASA animation outlining what all will happen through the duration of the Artemis I mission. Courtesy: NASA