by Douglas Messier
There’s an old saying that I made up just the other day. You can’t always get what you want, but if you test enough times, you get what you need.
Yes, I know. It’s unwieldy. And I expect a copyright infringement letter from the Rolling Stones’ shortly. Forgive me; it’s really hard to come up with a brand new saying that sounds old on short notice.
While we wait for the lawyers to weigh in, let’s talk about what happened over the weekend.
On Saturday, the long awaited, much hyped Green Run — the first and only planned hot fire test of the Space Launch System’s (SLS) massive core stage, key to sending astronauts back to the moon — was conducted at NASA’s Stennis Space Center in Mississippi. The plan was for the four reconditioned RS-25 space shuttle engines to fire for more than eight minutes in an eardrum-shattering cacophony of noise and exhaust.
After a long NASA-produced pre-test show featuring long periods of hissing from the rocket and a dearth of real-time information from human hosts, the engines did their thing. But, instead of going for the full eight minutes, they shut down after 67 seconds.
Well, it was nice while it lasted. And the test introduced a new acronym to the lexicon: MCF (major component failure), not to be confused with MCU (major crimes unit), MCI (defunct communications company) or M.C. Hammer (America rapper).
NASA put out a long blog post on Tuesday explaining the reason for the premature shutdown. You can read all the details here, but the long and the short of it comes down to conservative parameters placed on the test. The four engines shut down in accordance with the parameters. The engines and the core were found to be in excellent shape after an inspection.
The shortened test led to immediate calls by critics to cancel the massive rocket, which has been under development for more than a decade and blasted past every budget and schedule ever set for it. One writer called the test a bitter disappointment.
Well, yes and no. The program itself has been a major disappointment given the amount of time and billions of dollars put into it. You would think it would have launched something into space by now. It took NASA less time to develop the Saturn V during the 1960s with more primitive technology.
Adapting space shuttle technology originally designed in the 1970s seemed like a good idea to the politicians who approve NASA’s budget. It kept much of the shuttle workforce employed. But, it would probably have been faster and cheaper to have developed a new heavy-lift vehicle from scratch.
As for the test itself. It was just a test. As the old saying that I didn’t invent goes, this is why we test. We test to find problems so they don’t crop up when you fly astronauts. We expect failures — and often get them.
Some failures are far worse than a premature shutdown that leaves everything intact. If you’re lucky, all you do is destroy the vehicle and damage the test stand or launch pad. If you’re not, you end up having memorial services for fallen comrades. Just ask NASA, which has lost 17 astronauts in three accidents. Or Scaled Composites, which lost four employees developing SpaceShipTwo.
This is a dangerous business. It’s not for the feint of heart. And it punishes inadequate testing, deficient failure analysis and rushed schedules.
Unfortunately, there are signs that is happening here. NASA wasn’t conducting a hot fire on a test core, it was actually flight hardware. After this one and only test, NASA planned to ship the core down to Florida to launch an uncrewed Orion spacecraft on a mission around the moon later this year. If that flight test goes well, NASA is planning to launch a crew on only the second SLS flight.
That’s not how they did it in the old days. The Redstone, Atlas, Titan II and Saturn rockets that launch astronauts into orbit and to the moon the 1960s and 1970s were tested on the ground and in flight multiple times before NASA risked any lives on them.
The space shuttle was an exception to that practice. The vehicle’s first all-up flight was the launch of Columbia with John Young and Bob Crippen aboard. It was an extremely risky flight that nearly ended in disaster.
The force of liftoff moved the flaps at the back of Columbia more than anticipated. It also bent the connection between the shuttle and the external tank at the front of the orbiter. Young later said that if he had known what had happened, he and Crippen would have used their ejection seats to bail out and left Columbia to crash into the Atlantic Ocean.
Even though NASA didn’t come close to getting all the data it wanted or needed from the Green Run, officials have not decided whether they will attempt another test before shipping the core to Florida.
It seems the core only has nine lives, i.e., its propellant tanks can only be filled that many times. The stage has used up several of its lives already. Another test could stress components, potentially leading to a bad day when it comes time to launch it.
Officials said there’s another constraint: the two solid rocket boosters that will form the rest of the first stage have a limited lifespan once the five segments on each of them are stacked together.
The upshot is that NASA could end up risking its only completed Orion spacecraft, developed at a cost of billions of dollars, on a rocket whose core stage has been test fired precisely one time for a mere 67 seconds.
NASA engineers are pouring through the data and weighing the “trades”, i.e., the trade-offs of the risks, costs and schedule delays of doing a second hot fire vs. shipping the whole thing to the Cape and launching it into space.
No matter what NASA does, there is the risk of a launch failure that would be a far bigger setback than what occurred on Saturday. It’s a sobering thought for an Artemis program that is billions over budget and years behind schedule.