Monday, September 5, 2022

BE PREPARED FOR A ROLL-BACK


While everyone in the media is talking about the LH2 (Liquid Hydrogen) leak in the Space Launch System’s quick release connector, one small detail is somewhat overlooked.

When the current lunar launch window closes on Tuesday September 6, 2022, the certification date for the batteries in the vehicle command destruct system also expires. There is no way to re-certify the system at Launch Complex 39B because there is no access arm to that area of the booster. The only way to re-certify the system is by way of the access platforms in the VAB.

Thus, conjecture as to if or not the engineers need to construct some sort of weather shelter in order to service that leaky quick-disconnect in order to repair the LH2 leak at the launch pad is mooted unless they can get it all done and launch before the command destruct system expires.

Although the VAB provides plenty of shelter from Florida’s weather, the downside to a roll-back and repair indoors is that once the repair is finished there is no way to completely test the fix. The only way to test that fitting is to roll the vehicle all the way back out to Pad 39B where the LH2 can be fed into the system.

Additionally, although it has been discovered that the August 29 scrub caused by readings that one of the core stage’s RS25 engines was not being properly chilled was caused by a faulty sensor- it is important to point out that the KSC weather rules went red 16 minutes before the launch window opened. The weather continued in the red through most of the launch window. So, faulty sensor or not, the launch was scrubbed for weather before it ever got started.


 

Sunday, September 4, 2022

SLS... TROUBLED? OR JUST FLIGHT TEST?


The Space Launch System is on the pad... fueled and... scrubbed... twice.

To some arm-chair, self-proclaimed spaceflight experts this means that the whole thing is horribly troubled- a waste of money... as they peck feverishly away at their keyboards. After all, it disappointed nearly a million people who came to see it launch. And isn't that the whole point of this? 

Indeed to many myopic usernames on social media that is what the SLS/Artemis is... another Florida thrill-ride. You go there, tailgate at the causeway or along the river, and you get rewarded with big show. The sound of thunder as the vehicle rides a pillar of fire into the sky and out of sight.

And of course we have the SpaceX zealots who readily toss apples and oranges into the sky and call them the same thing. Surely Elon can do it better, and his massive rocket will be flying any day now. Never mind the fact that the sands at Boca Chica are mixed with both sea shells and stainless steel bits from that booster's development.

In fact the SLS/Artemis 1 launch is one and only one thing. It is an all-up FLIGHT TEST... period. 

Flight test is where you weed out those tiny weaknesses in the system. It is where you find those small buggy components that cost a lot of money to develop and now cost a lot of time to fix. Each can be frustration for the spacebuff to witness, but to the engineer each is simply a problem to be solved.

For those with history myopia, who scoff that Apollo never had such issues because everything was better then... I'd like to offer a look into the actual history. 

For example, AS-201 the first Saturn IB vehicle to be flown suffered from delays due to things such as mismarked electrical equipment and about 100 cables that were the wrong length being sent from Huntsville. Then wet-test was glitched by LH2 refusing to flow from the ground storage tank. Worst of all were the countless breakdowns in the RCA 110A computers that controlled the entire system. When the vehicle's Instrument Unit (IU) arrived at the cape it had scores of issues. IBM engineers benched it in hangar AF and fixed most of the problems on-site before the IU was stacked. Yet still the RCA 110A was filled with glitches. The results were months of launch delay.

Apollo 4, the first all-up Saturn V launch was delayed repeatedly while on the pad. First it was assorted computer issues. Then a monitoring system for propellant loading failed and a total of 1.9 million liters of propellants and LOX had to be drained from the vehicle. Problems in a gaseous helium regulator caused a delay and later a defective battery heater in the S-II caused a delay. In total there was a 17-day delay in what was only an Earth orbital mission. Had Apollo 4 been a Lunar mission, the individual  delays would have added up to several months as the Lunar launch windows came and went.

Of course you'll now say, "Oh sure, but that was long ago before they really knew how to do this and it was a new rocket. The SLS is made out of leftover Shuttle parts."

Wrong. The SLS is a new vehicle. The only true leftover shuttle parts are the four RS-25 core stage engines. Sure we have plenty of experience with LH2 handling, but it is still tricky stuff, especially when used in the quantities needed for the SLS. This launch will be the firing of the most powerful rocket ever launched by the United States. 

Take the delays- and get it right. Let's go to the Moon.