Early on Wednesday, NASA is trying for a third time to begin its campaign to send astronauts back to the moon. The mission, Artemis I, did not get off the ground in August or September after technical hiccups. Then, Hurricanes Ian and Nicole caused further delays. If the mission launches on Wednesday, the Space Launch System rocket and the Orion capsule will have no crew aboard. A successful flight could lead to a future mission that sends astronauts first to lunar orbit, then later to the moon’s surface.
The launch is scheduled for 1:04 a.m. Eastern time. In the case of unfavorable weather or a repeat of technical glitches, the liftoff can be pushed back as much as two hours, to 3:04 a.m. With a leak emerging after 9 p.m., it is likely the launch will occur later in the launch window.
NASA Television’s online coverage of the Artemis I launch began earlier Tuesday afternoon with a commentator describing the process of filling the rocket’s giant propellant tanks. The agency’s full coverage will begin at 10:30 p.m. You can watch it in the video player embedded above.
If Artemis I gets off the ground, coverage will continue for about two hours after liftoff through what is known as the trans-lunar injection engine firing to push the Orion spacecraft out of low-Earth orbit on a trajectory to the moon.
“It’s a future where NASA will land the first woman and the first person of color on the moon,” Bill Nelson, the NASA administrator, said during a news conference last month. “And on these increasingly complex missions, astronauts will live and work in deep space and will develop the science and technology to send the first humans to Mars.”
NASA is also hoping to jump-start companies looking to set up a steady business of flying scientific instruments and other payloads to the moon and to inspire students to enter science and engineering fields.
For scientists, the renewed focus on the moon promises a bonanza of new data in the coming years. There is a particular interest in the amount of water ice on the moon, which could be used for astronauts’ water and oxygen supplies in the future and could also provide fuel for missions deeper into space.
Scientists do not really know how much water is there or how easy it will be to extract the water from the surrounding rock and soil. Future missions could help resolve that question.
So far, no recurrence of the hydrogen leak after the bolts around the liquid hydrogen replenish valve were tightened. The radar problem apparently was caused by a bad Ethernet switch, which is being swapped out.
The first was Hurricane Ian, which devastated parts of southwest Florida in late September. NASA had plenty of advanced warning, and the uncertain path of the storm led to the Space Launch System and Orion being rolled back to the shelter of the giant Vehicle Assembly Building, or V.A.B., where it safely rode out the storm.
In preparation for the next launch attempt in November, the rocket trundled back out to the launchpad on Nov. 4. At the time, Hurricane Nicole was still an unnamed disturbance in the Atlantic Ocean, and forecasters did not expect a storm to form or strengthen into a hurricane. Once it did, NASA managers realized that they did not have enough time to safely put the rocket back indoors, and they decided it leave it outside.
“I think it’s safe to say, for all of us, we obviously would not have wanted to stay out there,” said Jim Free, NASA’s associate administrator for exploration systems. “The best place for the vehicle in those kinds of things is the V.A.B. We could not make it back to the V.A.B. and be safe.”
During the hurricane, a 100-mile-per-hour gust was recorded at the launchpad — but that was near the top of one of the lightning towers, higher than the rocket. Mr. Free said that the winds closer to the ground had not exceeded the vehicle’s design specifications.
Inspections revealed some minor damage, including some to a strip of caulk from the Orion crew capsule that sat on top of the rocket. On Monday, engineers finished an analysis that showed the missing 10 feet of caulk — added to smooth the flow of air during liftoff — would not cause problems.
Another problem. A radar needed to track the launch is offline. The U.S. Space Force, which is responsible for ensuring the safety from the Kennedy Space Center, is working to fix it.
If the NASA red crew’s leak fix was successful — and that remains to be seen — Derrol Nail, the NASA commentator, said that the time spent on the repair would “eat into the launch window.” That means that the liftoff is likely to occur later than 1:04 a.m. Eastern time. NASA has until 3:04 a.m. before having to call off the launch.
The red crew is still at the launchpad tightening bolts around the liquid hydrogen replenish valve, which NASA says has taken longer than the 15 minutes originally planned.
Even as Artemis I remains on the ground, a smaller piece of the Artemis program arrived at the moon. CAPSTONE, a 55-pound CubeSat, entered orbit around the moon on Sunday, four and a half months after it launched. The probe’s job is to study an orbit that is to be used for a future outpost where astronauts would stop on the way to the lunar surface.
Right after launch, mission controllers lost contact with the microwave-oven-size probe because of an inadvertent command sent to the spacecraft that told it to turn off its radio.
“That was pretty terrifying,” said Thomas Gardner, the program manager for the mission at Advanced Space, a small Colorado company that built the spacecraft and operates it. “We weren’t sure exactly what had happened, but once you figured it out, it was pretty easy to make sure it never happened again.”
In July, after thrusters were fired to adjust CAPSTONE’s course to the moon, contact was lost again. This time, a valve for one of the thrusters stuck, sending the spacecraft into a spin. Over the next few weeks, engineers successfully restored communications, diagnosed the problem and stopped the spin.
Because CAPSTONE took the slow, fuel-efficient trajectory to the moon, that gave the engineers plenty of time to troubleshoot before the spacecraft passed its destination.
NASA is now providing two streams on its YouTube channel — its official launch commentary programming from its main channel and “operational” updates on its media channel. Times journalists will monitor updates delivered at the Kennedy Space Center and on the media channel.
A similar leak occurred during the Apollo 11 countdown in 1969. From the transcripts of that mission: “We have sent a team of three technicians and a safety man to the pad and these technicians are now tightening bolts around the valve. Once the technicians depart, we will send hydrogen again through the system to assure that the leak has been corrected. The astronauts now coming up toward the pad itself as the crew of several technicians at the 200-foot level proceed to tighten some bolts around a leaking valve. The astronaut team which has just arrived at the pad, the transfer van now backing up toward the elevator. In a matter of 5 minutes or so, we’ll be ready for the spacecraft commander, Neil Armstrong, to come across the sill at the 320-foot level. That is our status at 2 hours, 43 minutes, 47 seconds and counting. This is Launch Control.”
The leak is at the liquid hydrogen replenish valve, located on the launch tower. It is a different location than the hydrogen leak that occurred during the second launch attempt on Sept. 3.
Once the technicians get to the launchpad, it should take about 15 minutes to tighten some bolts on a valve, NASA said, which may be contributing to the leak. They’ll be taking precautions because of the explosive potential of hydrogen.
Mission managers are still discussing sending a “red team” to fix an intermittent leak in a valve on the launch tower. Red teams also were ready during the space shuttle days for similar last-minute repairs.
For astronauts to get to the moon, they need a big rocket, and the Space Launch System is that rocket — the most powerful one since Saturn V took NASA astronauts to the moon in the 1960s and 1970s. The one waiting on the pad to launch on Wednesday is 322 feet high, and will weigh 5.5 million pounds when filled with propellants.
It will be able to lift more than 200,000 pounds to low-Earth orbit and send nearly 60,000 pounds of payload to the moon. Its cargo for this launch is Orion, a capsule that will be uncrewed for this flight but can carry four astronauts.
The rocket, known as S.L.S., resembles a stretched external tank that was used by the retired space shuttles, and the side boosters that help it get to space look a lot like engines the shuttles used.
This is by design: To simplify development of its new moon rocket, NASA reused much of the 1970s space shuttle technology. The rocket’s central stage is the same 27.6-foot diameter as the 1970s shuttle’s external tank, and it is covered with the same orange insulation.
The four engines in the core stage are the same as the space shuttle main engines. The first three Artemis missions actually use engines that were pulled from the old shuttles and refurbished. Because none of the S.L.S. rockets will be used more than once, NASA will run out of old shuttle engines after Artemis IV. New engines will be needed for Artemis V and later missions.
The side boosters are longer versions of those that were used for space shuttle flights. During the shuttle era, NASA recovered and reused similar boosters. But for the Space Launch System, which will launch only about once a year, the agency decided it would be easier and more economical to let the boosters sink into the ocean and use new ones for each flight.
The second stage of the S.L.S., which will propel the Orion capsule on a path to the moon once it gets to low-Earth orbit, is essentially a modification of the one used for another rocket called Delta IV. A new upgraded second stage will be used for Artemis IV, making the rocket even more powerful.
Development of the Orion crew capsule started in 2006 as part of Constellation, an earlier moon program started under President George W. Bush. Costs for Constellation soared, and the Obama administration tried to cancel it entirely in 2010.
However, Congress rebelled against that decision, leading to a revival of Orion and Ares V, the heavy lift rocket that was planned for Constellation, turned into the Space Launch System.
The Orion capsule is designed for trips that last multiple weeks in deep space beyond low-earth orbit. That means that the vehicle, while bigger than the Crew Dragon capsule that carries astronauts to the International Space Station, has a bit less space on the inside to make room for more robust life support systems.
Today’s countdown for NASA’s Artemis I mission has gone very smoothly so far. The propellant tanks of the core stage of the rocket are full already. The upper stage tanks are being filled now. There was no repeat of the hydrogen leaks that halted the last launch attempt in September.
source: The New York Times