NASA appears to be in full "send" mode for the Artemis I mission

NASA appears to be in full “send” mode for the Artemis I mission

Enlarge / Storm clouds threaten the Space Launch System rocket earlier this year.

Trevor Mahlman

On Friday afternoon, senior NASA officials participated in a conference call to discuss with reporters the current plan to launch the Artemis I mission from Kennedy Space Center in Florida. It will be the third attempt to lift off the massive Space Launch System rocket and propel the Orion spacecraft into lunar orbit for an uncrewed test flight lasting about 40 days before returning to Earth.

The rocket is ready, officials said. During refueling tests and launch attempts, NASA has been plagued by hydrogen propellant leaks, as the tiny molecule is difficult to handle and constrain in extremely cold temperatures. However, following a longer-than-expected but ultimately successful propellant loading test on Wednesday, NASA engineers expressed confidence in their revamped fueling procedures.

NASA has also reached an agreement with US Space Force officials to extend the battery life of the rocket’s onboard flight termination system. That left only weather as a potential constraint to a launch attempt scheduled for Tuesday, September 27 at 11:37 a.m. EST (15:37 UTC). The problem is that the weather now poses a significant threat to the calendar due to a tropical depression that will likely head into Florida in the next few days. There is an 80% chance of unacceptable weather conditions during the launch window.

To ride or not to ride

Despite the bleak forecasts, NASA is moving forward.

“Our plan A is to stay the course and do the launch on the 27th,” said Mike Bolger, NASA Exploration Ground Systems program manager at Kennedy Space Center. “We also realize that we really have to be careful and think about a plan B.”

Bolger explained that NASA’s backup plan involved bringing the rocket and spacecraft back inside the large Vehicle Assembly Building a few miles from the launch pad, where it would be protected from the elements. Preparing the rocket and rolling it back would take about three days, he said. NASA hopes to wait one day, until Saturday, to make a final decision. NASA officials will meet again on Friday evening to review the weather.

Those comments were reasonable, and it’s prudent for NASA to ensure it has the best available data on Tropical Depression Nine, which has only recently developed a circulation center. As a result, the forecast should improve within a day or two.

It’s a delicate balance for NASA – waiting long enough to get the best forecast, but also allowing enough time to roll back the rocket and free space center workers before the worst of the storm hits. According to the National Hurricane Center on Friday afternoon, the first “reasonable arrival time” for tropical storm-force winds is around noon on Tuesday, so waiting until Saturday morning would reduce it.

Off the tracks

After Bolger’s comments, however, the teleconference began to go off the rails somewhat. It became clear that NASA officials were not just waiting for forecast data, but reluctant to return the SLS rocket to its hangar. John Blevins, SLS’s chief engineer, said he wouldn’t be inclined to bring the rocket back to its hangar even if the space center were hit by a tropical storm, which has less winds than a hurricane but has when even a major punch.

“If we actually experienced a real hurricane, I would recommend that we consider rolling back,” Blevins said. “Usually the footprint of these things isn’t as wide, you know, for these high winds.”

Based on NASA risk analyses, Blevins said he believed the SLS rocket and Orion spacecraft could withstand winds of up to 74.1 knots (85 mph) at a level of 60 feet. of the ground. The main risk is the wind load on the vehicle, but he acknowledged there would be concerns about “things that could move around in a storm like this”. It’s a somewhat curious posture of risk from a space agency that is obsessively concerned about “foreign object debris” with its space hardware.

European model forecast at 12z for maximum wind gusts through Wednesday September 28th.
Enlarge / European model forecast at 12z for maximum wind gusts through Wednesday September 28th.

Weather Bell

So what’s the benefit of risking the rocket and spacecraft, which were developed at a cost of over $30 billion, in a tropical system? While waiting for the weather, NASA is looking to preserve a September 27 or October 2 launch opportunity. Otherwise, it will still have to return to the hangar.

That would likely push the next launch attempt into the second half of November. “Some time-limited items would arrive in this case,” Blevins said. It seemed like an admission that for NASA, time is running out on a rocket that has been fully stacked for launch for almost a year now, and has critical parts that cannot be repaired in this configuration. In short, NASA officials would very much like to leave the pad as soon as possible.

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