Archive for the ‘science’ Category

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Travel by asteroid

November 15, 2012

David Hardy painting of an asteroid-based spaceship

For a long time scientists and science fiction writers have postulated using an asteroid as either an orbital base or a non-FTL starship. Books like Mary Doria Russell’s The Sparrow use spacefaring asteroid ships because it appears to be a monumental problem to lift enough material out of Earth’s gravity well to build a starship from scratch. John Ringo’s Troy Rising series uses an asteroid, melted and inflated, as a fortress to defend Earth from aliens entering through a hyperspace gate.

SPOILER AHEAD! In fact, Ringo goes farther and, using an Orion-style nuclear bomb drive, turns his fortress into a mobile battle platform, taking it through the gate and to the battle.

I just finished Dr. Travis Taylor’s new book, A New American Space Plan, and I was struck by something that I never really considered much before. Maybe we can get to Mars using current, or near-future technology. NASA is now setting its sights on a mission to a Near-Earth Asteroid. (Or it was last I looked. NASA plans change every day.) Beyond that – let’s say we want to go to Jupiter – it’s going to be orders of magnitude more difficult. When the AE-35 antenna pointing unit failed in “2001” – OK, Hal did it, but still – they happened to have the parts or whatever to fix it. They didn’t have to, but were prepared to.

So let’s say we’ve got a Discovery-class ship, three crew in suspended animation, two minding the store on the Long Trip Out. Something breaks, or the classic Dramatic Meteor Impact happens and breaks something – something that is not available on the ship. We’re basically screwed. Don’t tell me 3D printing technology will save us. It won’t build a microchip for a really, really, long time. And a whole antenna, say 20 feet in diameter? Probably not. We don’t have Ringo’s fabbers, and if we have to wait for those, we won’t go to Jupiter for a long while.

We could do it by what Robert Zubrin, author of the “Mars Direct” concepts, derisively called the “Battlestar Galactica” approach: a gigantic fleet of ships, traveling together for mutual aid and protection. But if lifting one ship’s parts out of the gravity well is hard, lifting 20 is a lot harder.

So let’s see…maybe we can grab a Near-Earth Asteroid, bolt a bunch of stuff on it, drill it out or blow it out with nukes, and build a habitat inside. Maybe not for hundreds of people – let’s say, 50 or so. That’s a lot of lifting but not as much as the other alternatives. Ion drive, solar sail, Orion or Orion-derived nuclear pulse drive – any of them would probably work. It would just take a while to go someplace.

Look at it as if you are driving your motor home cross country and have to take your machine shop along because nobody stocks parts for your vehicle. The bigger the vehicle, and the more people, the more likely it is you can fabricate what you need. And most of the mass is nickel-iron asteroid, which is also providing a lot of radiation shielding. Instead of thinking of a trip to Jupiter as taking a few years, maybe you’ll take decades. Running a closed environmental system like that isn’t easy, but it’s easier than a lot of the alternatives. Eventually we’ll have some better drives, and we can get around the system faster.

Has anyone ever calculated how much toilet paper is needed for a five-year trip?

I don’t see this happening in the next 10 years, but it could be done a lot sooner than most every other idea I’ve heard for deep space interplanetary travel as long as we lack a superdrive. Those are based mostly on magic and good intentions right now.

Once we know how to do that, we can build bigger ones and send people to the stars. By then we should have a pretty good idea which ones have planets we could live on.

I wasn’t a fan of the NASA asteroid mission scenario until now. Now I hope we can get there. We won’t just be learning how the solar system is put together, but how to build a better spaceship.

A pity, though. I kind of like the Blake’s 7 Liberator as a spaceship design. Of course, it was built by aliens…

Blake’s 7 “Liberator” – lots cooler than flying a hunk of rock!

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Dad…is that you?

November 2, 2012

Johnny 5 from “Short Circuit,” 1986

Curiosity rover’s self portrait, ON MARS! – 2012

 

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Falcon 9 performs successfully even with one engine flameout

October 9, 2012

Sunday evening’s launch of the first commercial ISS resupply Dragon cargo craft appeared to go on without a hitch. However, it was discovered that, about at the point of maximum dynamic pressure, one of the nine Falcon 9 first stage engines failed. On-board video cameras recorded a gush of flame and pieces of something dropping off the booster. The onboard flight computer system ran the other engines about another 30 seconds to achieve proper speed and trajectory for the second stage to fire correctly and place the Dragon in the proper orbit. From there, a series of thruster burns by the Dragon itself will modify its orbit as it “chases” the ISS.

The flight computer did its job, but apparently a small Orbcomm satellite prototype, carried on the same second stage, was injected into too low an orbit as a result of the engine failure. There are very specific rules on orbital paths that are available in the vicinity of the ISS, and since deployment of the satellite was delayed, the second stage was not able to do an additional preplanned burn to put it in the proper orbit. Doing so would have interfered with the ISS “safety gate”window allowed for it. Remember, the previous Falcon 9/Dragon test flight was delayed several times because the launch window required to get the Dragon to the ISS was only one second long.

The Falcon booster is designed to be robust, and to have the ability to achieve its objectives despite an engine failure. The deployment of the Orbcomm satellite could have been accomplished if the ISS safety gate was not in place – there was nothing wrong with the second stage of the Falcon.

Unlike most European and American boosters, which use only one or two main engines in the first stage – often augmented by solid boosters, Russian Soyuz/Progress boosters have four rocket engines on the main central stage and four on each of the four “stage and a half” outer boosters. Solids cannot be “turned off” once they are burning – one of the safety concerns with the Shuttle and one also with the proposed/pipe dream heavy lifter NASA wants to build. That rocket could have either solid or liquid-fueled strap ons – my money is on Aerojet getting the contract to do liquid fueled boosters instead of ATK getting it for solids. ATK seems to not be the NASA favorite right now, and Pratt and Whitney Rocketdyne, one of the major liquid-fuel engine players, was recently  acquired by the parent company of Aerojet. (Aerojet builds most of the engines for the Delta rockets.)

So the booster has proven to be robust. Building and flying a rocket motor is not easy – the use of supercold liquid oxygen and high pressure/high temperature nozzle and thrust chamber make it tricky business. That is why today we rarely see a new motor designed from a clean sheet of paper. Most of the engines used today are improved varieties of designs from the 1960s, if not earlier.

I would think this flameout, despite it showing a less-than-100 per cent success rate, shows that a manned vehicle using this booster has a better chance of successfully reaching orbit than one with fewer engines. That, plus the powered escape plan using the improved Draco engines on the Dragon, should make this a safe and reliable passenger booster.

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Godspeed, Neil Armstrong…

August 25, 2012

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An earth-shattering kaboom!

August 9, 2012

This is NASA’s Morpheus testbed, designed at Johnson Space Center to test a number of technologies that are intended to be used in moon landings of unmanned cargo craft. When it had been tested in the past it was always tethered. This was the first untethered test.

There are fairly spectacular explosions at 1:56 and 6:21. The vehicle used LOX and liquid methane, which are considered less toxic than other storable propellants that could be used in moon missions.

It looked like the stability system failed almost immediately. It will be interesting to hear what NASA finds out in the investigation.

While this is a setback – I’ve not heard that there is a backup vehicle – this is often how we learn things in developing the technology of space travel. Things don’t always work perfectly the first time. 

That’s why I was relieved, but not necessarily happy, when the SpaceX Dragon mission worked out so well. There was tremendous pressure from the press, most of whom didn’t take any more science courses than absolutely necessary, that the flight had to go perfectly or SpaceX was doomed. Some went as far as to say that if it failed, commercial space flight would be considered a failure.

If you’re reading this, you probably pretty much automatically understand why that’s so much BS. The trouble is, a lot of people – maybe most people – don’t know that. They don’t know about the years of testing and failures involved in developing reliable complex remotely controlled systems.

In many ways we’ve been too good at the spaceflight thing. We have had failures that cost lives, but we haven’t flown nearly the number of flights we should have to validate spacecraft and launch vehicles. The Saturn V was so big, so complex, and so expensive that we couldn’t afford to blow a couple of them up, like the Soviets did with the N-1. (The final N-1 failed launch destroyed most of the pad as well as the vehicle, and they abandoned it – and going to the moon – altogether.) So we tested pieces and validated the hell out of systems and parts. Every single one of those low-bidder-manufactured million parts that went into an Apollo/Saturn V was had a paper trail pretty much back to the ore the metal it was made of came from. The Shuttle had to be man-rated from the very first flight.

So let’s blow up a few of these things if necessary, to learn what we need to know. Then let’s go out there!

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“Curiosity” on Mars!

August 6, 2012

The Mars rover Curiosity dropped onto the Martian surface just after 1:30 AM EDT today. It is the biggest rover yet to successfully land on Mars, at about 2000 pounds, about the same weight as a small car, according to NASA. (A Mini Cooper weighs just a bout 2500 pounds.) It weighs over four times that of the Opportunity and Spirit rovers that landed on Mars in 2004. Opportunity is still running around Mars, far beyond its design life, having traveled over 20 kilometers – and was designed to travel 600 meters!

Unlike the previous rovers, Curiosity has a small nuclear power plant. The others were limited by the amount of power that could be created by their solar panels. The extreme low temperatures of the Martian winter and the lack of sunlight caused those rovers to be movable only a few months of the year. The Curiosity’s power plant should provide about four times the power and has a design life of 14 years. One of the planned tasks is to drive over to the mountain in the crater where the rover landed, and climb it!

The most amazing thing about the landing is that the JPL folks developed a unique way to softly land the rover on the surface. A rocket powered frame was released a few kilometers off the surface, and the rover was lowered on cables while the frame hovered. And this was all done with no assistance from Earth!

I’m looking forward to the discoveries this rover will bring. It’s an astounding piece of technology!

 

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Happy Moon Day!

July 20, 2012

I almost forgot! Here’s some of the restored video of the Apollo 11 flight that put Neil and Buzz on the Moon on July 20, 1969.

I watched Armstrong’s first steps on a little black and white TV (not that it mattered), outside, at Farragut State Park in northern Idaho. I was a participant in the Boy Scout Jamboree that week. The whole thing was kind of surreal, somehow…knowing I was far from home, but these guys were…as alone as you could be. No, Mike Collins, in orbit, was as alone as could be. There has been a lot of talk about the close thing the landing actually was, before the LEM ran out of fuel, but what was it like to be in orbit in Columbia?

At the time I thought we were living in the future. Looking back, I am amazed at what was accomplished without all the high-tech enhancements we have today. Mini mp3 players have more computing power today than Apollo had!

Here’s to you, Neil, Buzz and Mike; and to everyone who was a part of that national dream given form.