With NASA’s powerful new 322-foot-tall moon rocket fully stacked at Kennedy Space Center, managers said Friday that Feb. 12 is the soonest the unpiloted Artemis 1 mission could blast off toward lunar orbit, a date that hinges on the outcome of a critical fueling test on the launch pad in January.
Ground teams at Kennedy this week installed an Orion crew capsule atop the Space Launch System rocket inside the Vehicle Assembly Building. The stacking milestone capped off the 322-foot-tall (98-meter) rocket inside High Bay 3.
“Completing stacking is a really important milestone,” said Mike Sarafin, NASA’s Artemis 1 mission manager. “It shows that we’re in the home stretch toward the mission.”
The mission, called Artemis 1, will send the Orion spacecraft to the moon, where it will enter a distant orbit in a multi-week, unpiloted “shakedown cruise” to demonstrate the SLS rocket and Orion are ready to carry astronauts. The next mission, known as Artemis 2, will send a crew of four around the moon and back to Earth, paving the way for future lunar landing flights.
The stacking allows NASA to complete final checks of the fully integrated launch vehicle. The integrated verification tests will lead to an end-to-end checkout of communications and data links with the launch control center at Kennedy and mission control at Johnson Space Center in Houston.
Tom Whitmeyer, NASA’s deputy associate administrator for exploration systems development, told reporters Friday that the Space Launch System and Orion spacecraft are scheduled to roll out of the Vehicle Assembly Building in late December.
Riding a mobile launch platform atop NASA’s Apollo-era crawler transporter, the rocket will head to launch pad 39B for a wet dress rehearsal, or fueling test, when NASA’s launch team will load cryogenic liquid hydrogen and liquid oxygen into the SLS core stage and upper stage.
The wet dress rehearsal serves as a final checkout for the rocket and the ground systems at pad 39B, and as an exercise for the launch team at Kennedy.
After the dress rehearsal, the rocket will roll back to the VAB for closeouts and final ordnance connections, then return to pad 39B six days before the target launch date.
Sarafin, a former space shuttle flight director, said Friday that NASA is aiming for a 15-day Artemis 1 launch period opening Feb. 12.
NASA has a 21-minute launch window available that day, opening at 5:56 p.m. EST (2256 GMT), but that time could be adjusted by a “minute or two” based on additional trajectory analysis, Sarafin said.
But Whitmeyer cautioned any discussion of a launch date is preliminary. NASA will set an official target launch date after the SLS wet dress rehearsal.
NASA has daily launch windows, some as long as two hours, available through Feb. 27, Sarafin said. There are additional launch opportunities available from March 12 through March 27, then from April 8 through April 23.
“We’re on for roughly two weeks, and then we’re off for about two weeks,” Sarafin said.
The launch periods are driven by the locations of the Earth and the moon, and NASA’s requirement for the Orion spacecraft to splash down in the Pacific Ocean during daylight hours.
“It really has to do with the three-body problem that we’re dealing with,” Sarafin said. “We have the Earth rotating on its axis. We have the moon going about the Earth in its lunar cycle in its … lunar cycle. And then we’ve got to head outbound, and then splash down in a set of daylight landing conditions.”
The Space Launch System’s upper stage, derived from the one used on United Launch Alliance’s Delta 4-Heavy rocket, will provide the Orion spacecraft with the speed required to escape Earth and head to the moon. Until NASA debuts a more powerful upper stage, replacing the single-engine Delta 4 stage with a new four-engine unit, Artemis missions will have intermittent launch periods lasting about two weeks.
Sarafin said the first half of the 15-day launch period in February would enable what NASA calls “long class” mission profiles running about six weeks in duration. Later in the month, there are shorter mission timelines available, each lasting around 26 days.
“The specific mission duration is going to depend on the day that we launch,” Sarafin said.
The Artemis 1 trajectory profile designed by NASA engineers will send the Orion spacecraft on a close flyby about 62 miles (100 kilometers) from the moon. Orion will use lunar gravity and a main engine burn to swing into a “distant retrograde orbit” around the moon, where it will stay for at least six days for a “short class” mission.
That’s long enough to complete a half-orbit of the moon in the distant retrograde orbit, some 40,000 miles (70,000 kilometers) from the lunar surface. A long class mission would involve flying Orion around the moon one-and-a-half times, according to Sarafin.
The Orion spacecraft will fly by the moon again to set a course back to Earth. The crew module will jettison its European-built service module just before re-entering the atmosphere, targeting a parachute-assisted splashdown off the coast of San Diego.
The U.S. Navy will deploy a recovery ship to retrieve the Orion spacecraft after splashdown.
“We’ve got some challenging mission priorities ahead of us,” Sarafin said. “We purposely pulled together a stress test for our Space Launch System rocket and our Orion spacecraft.
“Our four primary objectives are to demonstrate Orion’s ability to return from the moon in lunar re-entry conditions, to operate our flight systems in the flight environment, to retrieve our spacecraft, and then what I like to call bonus objectives,” Sarafin said.
“If you break those down a little bit further, in order to demonstrate Orion’s ability to return from the moon in lunar re-entry conditions, we need the rocket to do its job,” he said. “We need to take all that cryogenic fuel and solid propellant and chemical energy that we have on the ground and deliver the Orion spacecraft to the point of trans-lunar injection, and then take all that potential and kinetic energy out through friction when the spacecraft enters through the Earth’s atmosphere.”
The Orion spacecraft will utilize NASA’s Deep Space Network, a group of antennas positioned at sites in California, Spain, and Australia typically used to communicate with robotic science probes transiting the solar system. It will also fly above the GPS navigation satellites and traverse the Van Allen radiation belts.
“We’re going to see some remarkable photos from the wingtip cameras mounted on the end of the solar array wings,” Sarafin said. “Orion is going to take selfies of itself, and we’ll see the moon in the background and way off in the distance. We’re going to see the Earth some 270,000 miles away, and really gain a new perspective for the Artemis generation.”
NASA has a few more tasks ahead before launching Artemis 1.
Technicians are currently re-connecting umbilicals between the SLS rocket and its mobile launch platform. The umbilical arms retracted from the rocket during a release test last month.
The umbilical connections took longer than originally planned when ground teams went through the process earlier this year. That’s one of the reasons the Artemis 1 launch has delayed from late this year until no earlier than February, according to Mike Bolger, NASA’s program manager for Artemis ground systems at Kennedy Space Center.
This weekend, engineers plan to power up the Orion spacecraft for the first time on top of the SLS rocket. That will kick off a series of integrated verification tests through November to verify Orion and all the SLS rocket elements are properly connected and configured.
In December, NASA plans an end-to-end communications test between the SLS rocket, the Orion spacecraft, and ground control centers.
A countdown sequence test is also scheduled in December, when the SLS launch team will run through the countdown timeline with the rocket still in the VAB. That test is a “risk mitigation” exercise before rolling the rocket to pad 39B for the wet dress rehearsal.
“We’ve been really busy, and we’re going to stay busy for a while, and that’s the way we like it,” Bolger said.
Workers inside the Vehicle Assembly Building started assembling the Space Launch System last Nov. 20 with the lifting of element of the rocket’s solid-fueled boosters. With the boosters assembled, teams hoisted the core stage onto the mobile launch platform in June, followed by stacking of an inter-stage adapter and the rocket’s cryogenic upper stage.
Earlier this month, workers raised the adapter structure that connects with the Orion spacecraft on top of the SLS rocket. Finally, on Wednesday, NASA and its ground systems contractor Jacobs stacked the 74,000-pound (33.5-metric ton) Orion spaceship atop the launch vehicle and began the process of torquing 360 bolts to complete a firm mechanical connection.
With the launch vehicle now fully stacked, the Vehicle Assembly Building houses a moon-bound rocket and spacecraft for the first time since the Apollo 17 mission in 1972.
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