The Lileks review (scroll down). He’s not impressed. I’m pretty sure I’ll never waste time watching it.
Category Archives: Space
One Third Of The Way There
It’s been up less than 24 hours, but I’ve already raised 33% of my goal on the Kickstarter. Hope I can keep it up, and vastly exceed it.
The Problems With The Last Dragon Flight
…weren’t as bad as originally reported. I found this interesting, though:
As for the engine shutdown issue, data analysis has yet to result in any definitive conclusions. Although the analysis will continue, the observation that this particular engine had undergone a comparatively high degree of pre-flight testing, may ultimately lead to the conclusion that the shut down was related to the accumulating fatigue of an engine firing more than its nominal mission requirements. If this turns out to be the case; it would prove to be both somewhat ironic, as well as easily addressed by limiting cumulative firings for flight engines. Ongoing analysis has likely pushed the likely date of the next Dragon flight to ISS into the early March time frame.
Wouldn’t “limiting cumulative firings for flight engines” have interesting and problematic implications for reusability?
If this is really a problem, sounds like they’ll have to have a more robust engine design (or perhaps downgrade performance) for reusable versions. And of course, it’s possible that the new engine to start being used next year will resolve whatever the issue is.
Safe Is Not An Option
I’ve belatedly launched my Kickstarter project to publish my book on our irrational attitudes toward safety on the high frontier. I’ve put a short fuse on it — just fifteen days to raise four grand. I’d like to raise a lot more, to really publicize the thing, but that’s the minimum I need to have a quality product, I think.
Everyone who contributes at least five bucks will get some form of the book. Please consider donating generously, if you want to see this get more attention in the new year.
SpaceX And Radiation
John Muratore describes SpaceX’s approach to their SEU issues.
Space Safety Bleg
I’m about to launch another Kickstarter project to actually publish the Space Safety book (current title: Safe Is Not An Option: How Our Futile Obsession To Bring Everyone Back Is Killing Spaceflight). I’m trying to raise a few thousand to allow me to pay some people for a professional editing and illustration, and to start planning a symposium on the subject in conjunction with the Space Transportation Conference in DC in February, less than three months from now.
The book will probably be about a hundred pages, paperback. I don’t expect it to be a best seller at any price, but is ten bucks a reasonable number to get a book as a Kickstarter reward? I could sell for less, but I wouldn’t make much on it, unless I get enough interest to do an offset printing.
The Last Man On The Moon
I just wish that he wasn’t so ignorant about what’s going on currently in space policy, and wasn’t given so much credence by people who imagine he isn’t.
ISS Crew Research Time
It’s even worse than we’ve been told previously:
Suffredini pointed out that ISS operations require 15-17 flights per year and “then sprinkle in EVAs, it’s hard to find time to do research.” EVA refers to extravehicular activity, or spacewalks. NASA has a goal of performing 35 hours of research per week, but the current average is 26.13 hours. He is trying to find ways to “buy back crew time” and looking forward to the era of commercial crew when the typical ISS crew complement will be seven instead of six.
This means that rather than doubling productivity, adding a crew member would increase it by a factor of two and a half. And adding two would increase it by a factor of four (assuming forty-hour weeks — not sure why NASA only has a target of thirty five, or why it’s not even higher, given that they don’t have a hell of a lot else to do up there).
As a way of plugging my upcoming book:
To get back to the bizarre (at least that’s how it would appear to a Martian) behavior with respect to ISS, what is it worth? Of what value is it to have people aboard? We have spent about a hundred billion dollars on it over almost three decades. We are continuing to spend two or three billion a year on it, depending on how one keeps the books. For that, if the purpose is research, we are getting about one person-year of such (simply maintaining the facility takes a sufficient amount of available crew time that on average, only one person is doing actual research at any given time). That would imply that we think that a person-year of orbital research is worth two or three gigabucks.
What is the constraint on crew size? For now, not volume, and not the life support system – I don’t know how many ultimately it could handle, but we know that there is not currently a larger crew because of NASA’s lifeboat requirement, and there has to be a Soyuz (which can return three) for each three people on the station. If what they were doing was really important, they’d do what they do at Scott-Amundsen, and live without. After all, as suggested earlier, just adding two researchers would immediately triple the productivity of the facility. That’s not to say that they couldn’t be continuing to improve the safety, and develop a larger life boat eventually (the Dragon is probably very close to being able to serve as one now, since it doesn’t need a launch abort system for that role), but their unwillingness to risk crew now is indicative of how unimportant whatever science being done on the station really is.
Actually, I should update the book to reflect the new numbers.
Even with the concerns about Dragon issues, I’d bet that there are plenty of people who’d be happy to trust it as a lifeboat right now, though they really should get the new docking adapter up there ASAP. That is really on the critical path to expanding capability. Of course, if they were really serious, they’d do without a lifeboat or ambulance, as Scott-Amundsen does in the winter, and just add crew. I guess Antarctic research is more important than orbital research.
Single-Event Upsets
Marcia Smith has a report on the anomaly analysis for the SpaceX station resupply mission:
Several other problems also arose during the mission. While berthed to the ISS, one of the three computers on the Dragon spacecraft failed. Dragon can operate with only two computers, and SpaceX chose to proceed with the two functioning units rather than trying to fix the faulty unit while on orbit. According to Suffredini’s charts, Flight Computer-B “de-synched” from the other two “due to a suspected radiation hit” and although it was rebooted successfully, it was “not resynched.” Dragon experienced other anomalies because of radiation as well. One of three GPS units, the Propulsion and Trunk computers and Ethernet switch all experienced “suspected radiation hits,” but all were recovered after a power cycle. Suffredini said that SpaceX is considering whether it needs to use radiation-hardened parts instead, but noted that “rad-hardened” computers, for example, not only are more expensive, but slower. He speculated that the company would ultimately decide to use rad-hardened components in the future unless it is cost-prohibitive.
I had heard that there were also SEUs on the first ISS flight. It’s a young system, with very few actual flights, which is how you learn about things like this. But clearly it has enough redundancy for mission success (including in its ascent propulsion system). There’s a trade between using rad-hard components and utilizing more shielding. I assume that SpaceX is doing that trade right now (and perhaps has been doing so for months).
The Book Business
What does equilibrium look like?
This is a topic of increasing interest to me, as I’m trying to figure out how to publish my space safety book.