In my typical week, I spend a fair amount of bandwidth just deflecting the overwhelming volume of pixels gushing into my inbox and news feeds. By necessity and in the interest of survival, I skip past much of it.
But three things that caught my eye this week were all reports on NASA space ventures. Two made the mainstream evening news but I thought the most interesting one drew little notice. First, the big news: After years of delays, NASA finally launched the Space Launch System in the form of the Artemis 1 mission. The nighttime launch was a spectacular success, even if SLS is NASA’s biggest blunder yet. More on that later.
Second, the James Webb Space Telescope returned an image of what’s believed to be a protostar—a star in the midst of being formed. The hourglass-shaped object has a spherical center that’s being fed by filaments of hydrogen. When it reaches critical mass and gravitation, fusion will ignite and, pffft, a star is born. Astronomers also report seeing what may be planetary objects condensing out of the gas cloud. These observations were made in the near infrared and would have been impossible from earth-based telescopes. The object is 460 light years distant—the light from it left near the time of Copernicus.
I was 50-50 on whether JWST would succeed in unfolding itself, arriving on station and returning useful data. I was pretty sure that some $200 part or a misplaced washer would crump the whole thing. But clearly, at $10 billion, the telescope has thus far performed brilliantly. It took 30 years to bring it to fruition, so on an annual basis, it consumed a small fraction of NASA’s emaciated budget. Money well spent, in my estimation. Advancing astrophysics is a worthy cause and it’s been going on in fits and starts since the Catholic church told Galileo Galilei to cut it out.
Less of a worthy cause is the just-launched SLS. Let me re-phrase that. The cause (human spaceflight) is an inspiration, the instrument is not. While it’s thrilling to have Artemis 1 on its way to a circumlunar mission, it took vastly longer than it should have and NASA’s approach to developing the system essentially froze it with 1970’s propulsion technology, this from an agency charged with doing great things by inventing new technologies. Because of program cuts that killed the Constellation project, NASA put SLS together on the cheap, using leftover Space Shuttle engines, expanded solid rocket boosters and a larger, Shuttle-style external fuel tank. Except “on the cheap” is relative and in the case of SLS, far off the mark.
The entire expensive stack is expendable. Unlike the Shuttle, which at least recovered the SRBs, SLS will toss them into the ocean. When SLS was in the conceptual phase after the Constellation program was canned in 2010, the reusable booster wasn’t yet a thing, although I imagine SpaceX would have had it on the to-do list.
But it’s surely a thing now and SpaceX’s reusable Falcons are practically dropping back to earth like airliners at O’Hare. As predicted, this has driven down launch costs substantially and SpaceX plans reuse for the in-development Starship Mars rocket that will compete with SLS for heavy interplanetary lift. Both of those boosters are propelled by cutting-edge Raptor engines SpaceX developed just for the purpose and it married their operation to reliable recovery and reuse. SLS, meanwhile, is old school Apollo, freshened by Shuttle hardware.
This has long-term implications for program costs. SLS launch costs are expected to be in the $2 billion range but SpaceX claims once it’s fully developed, the two-stage, reusable Starship system might launch for as little as $110 million, as reported by Center for Growth and Opportunity’s Eli Dourado. Because it has on-orbit refueling capability, the Starship system has potentially higher payload capacity than SLS, which may become a system that’s economically dead-ended. (That $110 million applies to a pair of boosters, one a tanker.)
The only reason SLS survived what NASA knew was the coming era of commercial space and will likely continue to survive is politics. Many states have SLS contractors employing hundreds if not thousands, so the votes were there to carry on a vastly delayed and overbudget program. The pork barrel, as it always has, continues to roll. On the plus side, the program maintains a diverse aerospace skill base and capability. But it’s a terribly inefficient way to run a rocket program, in my view. At least the launch was all but flawless, which it oughta be given the number of zeros in the mission invoice. As a space and rocket groupie, I can’t even bite my lip because it’s agape at the mere sight of all that fire and fury. At long last, have you left no sense of awe?*
The other NASA achievement which I thought was spectacular but got little notice is something I wouldn’t have thought possible: An inflatable heat shield. Yeah, you read that right.
Let’s review heat shields. In the early days of the space program, the Mercurys through the Apollos, heat shields were ablative. That means they were composed of a metal honeycomb filled with phenolic epoxy resin that was designed to boil off during the heat of entry, carrying the heat away in an incandescent plasma cloud. Later, the Space Shuttle used porous silica tiles that worked like refractory bricks in an industrial oven, insulating the underlying structure from heat transfer.
With Mars in mind and much larger payloads, NASA just tested what it calls the Hypersonic Inflatable Aerodynamic Decelerator or HIAD. The shield itself is made of woven ceramic silicon carbide thin enough to be bundled into a flexible yarn. The yarn is woven into a cloth based over a ceramic layer that protects an inflatable structure, sort of like a stack of inner tubes. The whole thing can be stuffed into a bag much smaller than the rocket’s fairing, then on entry, inflated to 20 feet in diameter for the test flight, versus 13 feet for Apollo capsules. Given the temperatures involved, at least 2300 degrees F for Earth-orbit entries, the whole thing seems daft.
But on Nov. 10—actually the week before last week—NASA successfully launched the system on an Atlas 5. It inflated as planned and shielded a payload during an 18,000-MPH entry, splashing down successfully in the Pacific. The mission was called Low Earth Orbit Flight Test of an Inflatable Decelerator or LOFTID. Some version of the system might be suitable for Mars rockets, which might be attempting to enter the Martian atmosphere with as much as 100 tons of payload on a large diameter rocket. (SpaceX, whose Starship is 30 feet in diameter, will use a tile heat shield system.)
These spacecraft, presumably with people aboard—many people if you believe SpaceX—will be carrying a lot of luggage. NASA figures at least one of those bags can even carry a heat shield. Hell of an idea.
*Apologies to Joseph Welch.