Alan Boyle is going to be at The Grove in LA tomorrow night for a book signing. I may try to make it.
[Update a few minutes later]
Speaking of Alan, he has a roundup of the latest prospects for fusion — cold, medium and hot — over at Cosmic Log.
Alan Boyle is going to be at The Grove in LA tomorrow night for a book signing. I may try to make it.
[Update a few minutes later]
Speaking of Alan, he has a roundup of the latest prospects for fusion — cold, medium and hot — over at Cosmic Log.
Following up on yesterday’s star chamber in Congress, Jon Goff points out that when it comes to safety, NASA is comparing apples to eggs when it comes to Constellation versus commercial crew requirements.
I got a question via email:
I have often heard of the difficulty of getting mass to orbit. Earth’s atmosphere and gravity are on the edge of being too much for chemical rockets. Unfortunately I have not found any discussions that analyze modified case scenarios such as “What if Earth had a thicker atmosphere?” or “What if the atmosphere was roughly equivalent but the gravity was 10% greater?” Would these be game stoppers for chemical rockets?” If we had evolved on Venus what method would be best for getting to orbit? Ultimately, are we in a sweet spot as far as our planet is concerned, too big to loose the atmosphere but not to big to be stuck?
It’s a misconception that it’s too hard to get off the planet with chemical rockets. Earth’s gravity is bad for single-stage, but as long as you’re willing to stage, it’s not that big a deal. What makes it expensive is the low activity rate, not the intrinsic capabilities of chemical propulsion. Ignoring the fact that it would have been very unlikely that we would have evolved on Venus, the best way might be a hot “air” balloon to the top of the atmosphere, and then take off from there. Designing a propulsion system that would work in that atmosphere would be no fun. Commenters may have other thoughts.
Jeff Foust has some good questions in preparation for today’s hearing:
* What would be the safety implications of terminating the government crew transportation system currently under development in favor of relying on as-yet-to-be-developed commercially provided crew transportation services? What would the government be able to do, if anything, to ensure that no reduction in planned safety levels occurred as a result?
* What do potential commercial crew transportation services providers consider to be an acceptable safety standard to which potential commercial providers must conform if their space transportation systems were to be chosen by NASA to carry its astronauts to low Earth orbit and the ISS? Would the same safety standard be used for non-NASA commercial human transportation missions?
* If a policy decision were made to require NASA to rely solely on commercial crew transfer services, which would have to meet NASA’s safety requirements to be considered for use by NASA astronauts, what impact would that have on the ability of emerging space companies to pursue innovation and design improvements made possible [as the industry has argued] by the accumulation of flight experience gained from commencing revenue operations unconstrained by a prior safety certification regime? Would it be in the interest of the emerging commercial orbital crew transportation industry to have to be reliant on the government as its primary/sole customer at this stage in its development?
The problem is, of course, that this will not be either an honest or informed discussion, because there are so many rent seekers involved. I was glad to see Patti stand up for commercial industry, though.
More hearing coverage and links over at Clark’s place.
[Update a few minutes later]
You’ll be as shocked as I am to learn that NASA (once again) lied to the Augustine panel and withheld information about Ares/Orion safety. Well, at least they’ve been honest about their costs. And schedule. Right?
I agree with Ray — this is Powerpoint engineering at its finest (which is to say, worst). I’ll be very interested to hear what Joe Fragola has to say about this at the hearing today.
[Mid-morning update]
Well, now we know what Fragola thinks:
Fragola says that Atlas 431 would likely not pass a safety review for crew missions since it uses solid strapon boosters.
OK, so strap-on solid boosters that have never had a failure, on a launcher with a clean record — unsafe. A giant solid first stage that has never served in that solitary role — safe. Got it.
[Update a few minutes later]
Another tweet from Jeff:
Gifford closing out hearing, thanks witnesses for “briliant” testimony. Says she sees no grounds for changing course based on safety.
Well, neither do I. The reasons for changing course is cost and schedule, not safety. In fact, I’d be happy with a system much less “safe” if it actually accomplishes useful things in space, which Ares never will, because it’s unaffordable.
[Update a few minutes later]
A lot more detail from Bobby Block over at the Orlando Sentinel:
Fragola said that the passage quoted by the Sentinel story from the Exploration Systems Architecture Study concluding that it would take at least seven flights (two test flights and five mission flights) before the Ares I and Orion crew capsule could to be deemed to be as safe as the shuttle referred to a more powerful configuration of Ares-Orion that used a liquid oxygen-methane engine and not the simpler lower performance configuration being designed today.
Of course, the very notion that one can know or even properly estimate the safety of a vehicle with so few flights under its belt remains absurd.
[Update late morning]
Clark Lindsey has what looks like a first-hand report.
[Late afternoon update]
NASA Watch has the prepared statements from the hearing.
A lot of USians will be able to see it tonight. And you don’t have to stay up late, it’s only an hour or so after sunset, at least on the left coast. Go here and plug in your zip code for azimuth and elevation.
[Update a few minutes later]
Heavens Above is another good place to go, where it says that ISS is now sufficiently bright with all of its arrays that it is visible in the daytime, if the sun is low enough.
Jeff Foust reports on an upcoming hearing on the safety of human spaceflight. As he notes, there is only one obvious proponent of commercial provision of such services asked to testify. I don’t know what General Stafford thinks about the subject, but I fear it. And note that no one from the FAA-AST will be present, though they will probably be involved, eventually, with passenger safety on commercial vehicles. The worst thing, of course, is that the hearing will be chaired by Jim Oberstar, who is on record as being hypersensitive to safety issues at the expense of progress. That’s unfortunately one of the consequences of the past two elections, though hopefully it will be rectified next November. Expect to hear a lot of talk about how the private sector can’t be “trusted” with the safety of astronauts, but that the agency that has killed fourteen of them in the past quarter century can.
Over at The Space Review today, Stephen Ashworth responds to the idiotic Space News piece by the ESA guys last week. I generally agree with his critique, though he’s far too fond of airbreathers.
…make better Star Trek? John Scalzi thinks not.
Brian Swiderski has a roundup of videos and pictures of a lot of space hardware under development by private space.
Jon Goff has an interesting variation on a concept that’s been around for a long time, but never implemented: refueling a suborbital vehicle in space to allow it to get to orbit. It’s in between Black Horse, which did an aerial fueling (or rather, oxidizing, since the propellant transferred was the oxidizer rather than the fuel), and standard orbital refueling. There’s an up side and a down side to it, relative to aerial refueling.
The down side is that unless the suborbital trajectory is fairly high, at least in velocity, you don’t have a lot of time for the operations before entering the atmosphere. You’d only have a few minutes, but that might be enough to transfer several thousand pounds of propellants. You’d have a trade as to whether to transfer just fuel, or just oxidizer or both. The latter would increase the likelihood of failure, since you’d have to mate two transfer booms, and simultaneously transfer two fluids.
The up side is that, out of the atmosphere, it’s easier and safer to fly in formation, because there are no wind gusts to worry about, and the physics is much more predictable (gravity doesn’t tend to vary much over non-astronomical times).
In a sane world, NASA would have long ago built an X-vehicle to prove out the concept, but that’s not the world in which we live. What I’d like to see is a prize for the first demonstration of such a propellant transfer operation, which all of the suborbital folks – Scaled (or VG), XCOR, Masten or Armadillo or others — could go after. You could have tiers of total propellant transferred, or total propellant transferred in a given time.
The other appealing thing about it is that, as Jon notes, it has benign abort characteristics. Which brings to mind another prize that NASA could offer (again, in a sane world). If reliability is really valued (the focus on heavy lift in general, and Ares in particular, would indicate that it’s not particularly, despite the advertisements), like low cost, it will only be achieved through high flight rates, and no one will really believe it until it’s been demonstrated. Fortunately, reusable suborbital vehicles are capable of lots of flights for low marginal cost per flight. So all they need is funding to do lots of flights. I would propose a prize for a consecutive number of successful deliveries to orbit (you could even start off with suborbital missions). Or, rather, consecutive number of non-failures, where failure is defined as losing the payload. In other words, you wouldn’t be penalized for an intact abort. The prize would be won when the requisite number of missions were flown with no losses. Abort rate could be a tie breaker for multiple winners.
If you wanted to have a demonstrated reliability (defined as non-payload loss, not mission success) of 0.999, you’d have to fly a thousand flights. If the marginal cost of a suborbital flight is, say, $10K, this would cost ten million, about the same as the X-Prize. So offer a fifty-million dollar prize, and see who goes for it. Once that’s won, offer half a billion for orbital.