Monday, May 10, 2010

Roundup

Heavy-lift, alive but knee-capped.

In his April 15 speech at NASA’s Kennedy Space Center, Fla., U.S. President Barack Obama said the space agency would spend the next five years studying new technologies and materials before settling on a heavy-lift rocket design. But NASA documents and comments from agency officials suggest the White House already has a design firmly in mind.

The document was revised between May 3 and 5 to eliminate a particularly foolish fuel constraint. Spaceref has the modified request.

Summary: We're going to take five years to reinvent Ares V, and God knows how long to actually build, test and the fly the damned thing...if at all.

Nothing of interest from the ISS.

Summary. People woke up, ate breakfast, popped pills, vlogged, and tightened bolts.

Ice and chemicals on 24 Themis:

Scientists using a NASA funded telescope have detected water-ice and carbon-based organic compounds on the surface of an asteroid. The cold hard facts of the discovery of the frosty mixture on one of the asteroid belt's largest occupants, suggests that some asteroids, along with their celestial brethren, comets, were the water carriers for a primordial Earth. The research is published in today's issue of the journal Nature.

"For a long time the thinking was that you couldn't find a cup's worth of water in the entire asteroid belt," said Don Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "Today we know you not only could quench your thirst, but you just might be able to fill up every pool on Earth – and then some."

Outstanding. Now how about finding a similar near Earth asteroid that we can actually use?

Another conservative drinks the Flexible Path kool-aid:

We free-marketers know that the free market can make improvements, cut costs, and make innovations based on the actions of the competitive marketplace. Manned space flight as conducted by NASA over the last fifty years had none of this. As a result, we have a 35-year-old design (shuttle) that flies very little and is increasingly accident-prone. In the 35 years from the Wright Brothers' first flight in 1903 to 1938, we went from the Wright Flier to the B-17. Why hasn't there been similar progress in manned space flight? The answer is that it has been a government monopoly for fifty years.

We're coming up on the 25th anniversary of the Commercial Space Launch Act, we've grown a quarter trillion dollar industry that has all but run out of excuses to launch satellites, and we were moving towards commericial transport to the ISS five years ago. The problem isn't government sponsored manned space flight--which is the only reason anyone's up there in the first place. It's that government manned spaceflight has no direction whatsoever. Flexible Path is just the first time a White House has had the balls to come out and say it.

Colin Doughan has a blog, interviews Alan Wasser on property rights in space:

Sending astronauts to the Space Station will be the first revenue stream for private space development. The second revenue stream will be space tourists, starting with the very rich, of course, but expanding as soon as possible to an ever widening segment of the public.

Unfortunately, however, those and all other currently identified revenue streams added together aren't enough to attract real venture capitalists, only enough to attract rich philanthropists.

Interesting. So, how do you get to your new lunar homestead?

Paul Spudis on lunar water:

A significant amount of water at the poles of the Moon is present, with many billions of metric tonnes at each pole (detailed estimates of the water reserves are in progress). Such an amount is more than enough to support both permanent, sustainable human presence on the Moon and for export to cislunar space.

We know we can live on the moon. We've got good reason to believe we can industrialize the Moon. So why do we have a space policy that isn't focused on getting us back there as soon as practically possible?

Revealing insight into NASA's continuing lack of seriousness where it concerns commercial:

Case in point: Falcon 9 is ready to go. All that is preventing a launch is final approval of its flight termination system -- an explosives-and-communication system that lets safety officials blow up a rocket in flight if it's off course or somehow a threat to people or property below.

Falcon 9 has a flight termination system. But current rules require tracking the origin of every piece and part in the system, forcing SpaceX to use older components and a limited supplier base. The company would rather use modern, off-the-shelf components, that could be obtained from a broader range of suppliers -- likely at a substantial cost savings. It'll work out, but it's taking extra time and money.

It's bad enough we're going to pretend that a commercial purchasing with one customer is something new and substantially any different from the contracting that drives NASA's entire goddamned history. But can we at least get the Marshall folks out of SpaceX's hair?

Saturday, May 8, 2010

"The engine is actually firing right now."

Not exactly why this was news this week. VX-200 successfully test fired in 2009, and it looks like Ad Astra's facing a 2 year delay before they can start their space-borne VF-200-1 tests.

Economic Times
WASHINGTON: NASA is looking forward to flying a plasma-powered rocket to survey an asteroid that could take astronauts to Mars in a little over a month's time.

The rocket called Variable Specific Impulse Magnetoplasma Rocket (VASIMR) is a twin of one being developed for testing aboard the International Space Station.

VASIMR technology uses radio waves to ionise propellants like argon, xenon or hydrogen, and heat the resulting plasma to temperatures 20 times hotter than that on solar surface. It uses magnetic fields instead of metal nozzles to control the direction of the exhaust.

Equipped with an electric propulsion system, the rocket is being built to transport astronauts to Mars in 39 to 45 days someday - a fraction of the six to nine months the trip would take with conventional chemical rockets.

Why is electric propulsion important? Let's dig out our old friend the rocket equation:



The range of missions you can attend given an engine configuration and some payload mass is entirely determined by Δv. The higher this is, the more destinations you can reach. We can even ignore thrust--more accurately, acceleration--to a point, provided you're not blasting off or landing from any body with a significant amount of gravity. Once you're off Earth with a mission to encounter something, all that really matters how much can you change your velocity.

When choosing your engine, the effective exhaust velocity (v_e) is the key sorting factor.  For a chemical rocket, this is going to be around 1000 to 5000 meters per second.  Knowing v_e allows you to figure out the ratio of launch mass to payload (m0/m1) for a given delta-v.  A lunar encounter, for example, requires a delta-v of just under 11 km/s.  So, for every kilogram of payload you take with you to the moon, you'll need 8 kg of fuel.  If you can improve exhaust velocity, you can reduce the amount of fuel you need to reach a given destination *or* increase the amount of mass you can take to the same target. Electric engines like VASIMR offer our best near term hope for increasing exhaust velocity.

There is a cost, of course. To achieve high exhaust velocities, you choose propellant with low mass and consequently low thrust. A trip to the moon that might take forty days for Apollo could take weeks using a plasma engine. On the other hand, a solar powered VASIMR spacecraft keeps accelerating towards the end of its delta-v budget, which means while a chemical rocket ship would have to cost in transfer between Earth and Mars over a period of 2 years, our electric engine ship could make the journey in a few months.  With a nuclear reactor rated at 1 kg/kW, the trip could be reduced to six weeks.

But why bother with Mars? The moon has a far lower surface gravity and plenty of resources, and near Earth asteroids are even more cost-effective targets.  Near Earth space is a 1300 W/m^2 gold mine of solar power. And all of it is within reach of electrically propelled spacecraft operating on nothing more than 7 kg/kW rated photovoltaics.

Saturday, January 3, 2009

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