gedmark

Using 50 year old Russian engines was a risky move on Orbital's part, but in fairness the NK-33's are a pretty amazing piece of technology. The US has still yet to build anything matching its performance:

http://en.wikipedia.org/wiki/NK-33

297 seconds of Isp is huge. The Saturn V's F1 engine only had 263 seconds. And the closest we've come since to that level of performance in a Lox/RP-1 engine is the Merlin 1D which will have 282.

They did it by using an oxygen-rich, fully staged combustion cycle. Which means that most of the fluid flowing around the engine and through the turbines of the pumps is super hot pure oxygen at 2000 psi. That's crazy. The US has brought over NK-33's and taken them apart and we still don't quite know how the Russians got it to work.

Of course, performance is only one consideration. All the other things you'd expect like integration costs, reliability of your suppliers, etc. made the Antares a pretty risky bet. But given Orbital's choices of developing their own engine from scratch, buying a hyper-expensive engine from Rocketdyne, or buying a wonder of engineering for cheap from the Russians, buying a bunch of surplus NK-33's wasn't totally crazy.

Insane is a better word for it. Although to be fair there are a lot of aspects of the shuttle's design and operation that will be remembered that way.

He even glosses over the SRB issue. Thanks to the SRB's, there were no abort modes for the shuttle during the first 123 seconds. Until they had expended themselves any abort would have required separating the SRB's while they were still firing at full thrust. They would have accelerated forward of the stack, their hot exhaust impinging directly on the external tank while it was still full of fuel.

The RTLS was insane, but I don't think it comes close to the madness of STS-1: http://en.wikipedia.org/wiki/STS-1

That flight will go down in history as the only time anyone was dumb enough to put people on top of a rocket on its very first flight.

"Unlike previous phases of NASA’s commercial crew program, which used funded Space Act Agreements that provided greater flexibility, the CCtCap awards are fixed-price contracts."

http://www.spacenews.com/article/civil-space/41891nasa-selec...

It's pretty straight forward. SpaceX can do the same work with less money for a variety of reasons. And SpaceX has a capsule that has already flown in space and successfully docked with the ISS several times to deliver cargo. They are 'just' upgrading it to carry people. Boeing has not flow their capsule yet, they're playing catchup.

Surprised this is the top comment. Your first link is reporting on an unrelated military program to replace the RD-180 rocket engine. The other four links are all blog spam using the same source: the Wall Street Journal article by Andy Pasztor. Pasztor is well known in the aerospace industry for writing what you might call "speculative" articles based on not much more than rumor.

Edit: here's the WSJ article so people can go to the original source. You'll need the google trick to get around the paywall. http://online.wsj.com/articles/boeing-takes-lead-to-build-sp...

Fair warning I don't think it has any actual news content. The expected outcome was that Boeing and SpaceX would both be winners, but because SpaceX is always cheaper, Boeing would get a larger amount of money.

It certainly could be true, but the official announcement is in two hours so probably just makes the most sense to wait and see what happens rather than post more speculation.

The right answer is they should fund all three. That was the intention of the program from the beginning. This would likely look like two full awards and one "half" award that would be more of a technology development effort. The reasons are three-fold.

1) Cost savings. If you look at the joint strike fighter as an example, as long as Boeing and Lockheed were both in the game costs for the program were historically low. Both companies built and flew prototype aircraft for $750 million each. That's crazy cheap. It was only after down-selecting to a single aircraft that the costs of the program ballooned out of control, because that's how defense contractors play the game when they have no competition. NASA's Ares and Orion programs, by contrast, were contracted out to various single winners from the beginning, who quickly ran up the tab.

2) Backups. In case one runs into technical difficulties, NASA will simply order more of one of the other companies. If you have a single winner, any kind of incident with either the launcher or the spacecraft will mean a stand-down of US human access to space for months, not years.

3) Variety of capability. Multiple winners means a variety of designs, differing capabilities, and a larger variety of technologies developed that might be useful for future spacecraft. E.g. SNC's horizontal landing.

Source: I had a hand in the initial design of the program.

Just from what I've read - At 1st stage separation the F9 is going Mach 10 at an altitude of 80km.

There's no hard and fast definition of how high/fast you need to be going for it to count as a "re-entry", but that certainly qualifies.

Just to set expectations, SpaceX has tried to recover the 1st stage of almost all of its launches to date. (Using just parachutes for most of them). They've yet to successfully recover a first stage.

Their most recent test went pretty well all things considered. For the first time they tried a "death swoop" maneuver, turning the 1st stage 180 degrees around as it was starting to re-enter and refire some of the engines to slow it down. It picked up a nasty roll though and centrifuged the propellant, cutting the engines prematurely. They recovered some debris but that's about it.

It's hard to overstate how big a deal it will be if they pull this off. But the odds of success are very low, given the propensity of these things to tumble and roll on reentry.

> one way to deal with this may be to have engineering teams on stand-by, ready to helo to a broken drone ship and do repairs.

Very few helicopters have a range >600 nm one-way. That puts a lot of places a ship could be in the shipping lanes well out of range.

Interstellar probes will get to be pretty cheap with sufficient economic growth. We should be able to easily afford >0.1c probes in 100 years or so on our current economic trajectory. And if our civilization advances for another 1000 years they'll be a piece of cake.

If those probes are Von Neumann machines they can spread throughout the entire galaxy in as little as a few million years. That's the crux of the Fermi Paradox - on galactic timescales any sufficiently advanced civilization should be able to expand its presence to the entire galaxy pretty easily and quickly.

I was puzzled by this as well. I'm not familiar with a "wolf hypothesis" and a google search doesn't turn anything up.

I'm pretty sure he's talking about the Zoo Hypothesis. i.e. our presence is known to other intelligent civilization(s), and for whatever reason they've decided to hide themselves and not engage. Like a village would refer to wolves in the surrounding forest.

For this to work though, you have to have one advanced civilization that has either absorbed the others ("unitary") or powerful enough enforce the rules. Otherwise it would be pretty inevitable that out of a hodge-podge of civilizations one of them would say screw it and engage.

Aerospace engineer here (now doing software stuff). Around the time I left my alma mater was doing a good job shifting to more courses that involved actually building hardware. Their term for it was DBT for "design, build, test."

It's expensive though. A lot of times students have to go fundraise to pay for their projects. My annual donation to the university is now earmarked specifically for supplies for a couple of undergrad DBT courses.

I'd encourage you to get back in touch with your old department and give them your above feedback, I'm sure they'd love to hear from you.