Tag: engineering

Ground controllers replace a failed circuit box on ISS, using the robot Dextre

6:31 pm

Ground controllers successfully replaced a failed circuit box on ISS this weekend, using the two-armed Dextre robot.

Up to now, exchanging the boxes was done by spacewalkers, which always carries a certain level of risk. Dextre was designed to reduce the need for astronauts to conduct spacewalks for routine maintenance, therefore freeing up the crew’s time for more important activities, like conducting science.

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A preliminary cause for the Russian launch failure has been found

9:19 am

Good news: The Russians have pinned down a preliminary cause for the Progress launch failure last week.

Solving this quickly appears essential, as the space station was not really designed to fly unmanned.

Past NASA risk assessments show there is a one in 10 chance of losing the station within six months if astronauts and cosmonauts are not onboard to deal with any critical systems failures. The probability soars to a frightening one in two chance — a 50-percent probability — if the station is left without a crew for a year.

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Al Gore and the silencing of debate

3:48 pm

Yesterday I posted a link to a story about Al Gore claiming that any expression of skepticism about global warming is to him no different than racism. Here again is what Gore said,

“There came a time when friends or people you work with or people you were in clubs with — you’re much younger than me so you didn’t have to go through this personally — but there came a time when racist comments would come up in the course of the conversation and in years past they were just natural. Then there came a time when people would say, ‘Hey, man why do you talk that way, I mean that is wrong. I don’t go for that so don’t talk that way around me. I just don’t believe that.’ That happened in millions of conversations and slowly the conversation was won. We have to win the conversation on climate.”

More than at any other time, Gore here has very successfully illustrated the differences between how climate skeptics debate the scientific questions of climate change versus how global warming advocates do it.
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Sponge in space

2:38 pm

Hyperion

On August 25 Cassini did a close fly-by of the small Saturn moon Hyperion, getting as close as 15,500 miles. The mission has just released images from that fly-by.

Looks like a sponge, doesn’t it? This moon is small, only 168 miles across, which makes it about half the size of the asteroid Vesta that Dawn is presently orbiting. Why it is so peppered with craters is of course the big science question. I would guess this has something to do with the environment around Saturn, with its rings and the innumerable particles that come from it. Yet, other moons of Saturn are not as crater-filled, so there is obviously more to this than meets the eye.

This fly-by was the second closest of Hyperion that Cassini has done, the first passing over the the moon’s surface by only 310 miles. Because the irregularly-shaped moon’s rotation is more like a chaotic tumble, scientists could not predict what part of the surface they would see. To their luck the new images captured new territory.

Another fly-by is scheduled in only three weeks, on September 16, 2011. This time, however, the spacecraft won’t get as close, passing at a distance of about 36,000 miles.

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When dust, pebbles, rocks, and boulders act like liquid

3:35 pm

The science team of Lunar Reconnaissance Orbiter released an intriguing picture yesterday of what scientists call a granular flow down the side of a five mile wide crater on the far side of the moon. Looking at the image, one would swear that the darker material flowing down the slope of the crater rim is a lava flow frozen in place.

lunar granular flow

However, according to the scientists, that is not what it is. Instead, this is merely debris left behind from an avalanche.
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Capturing an asteroid into Earth orbit

12:30 pm

orbital path after asteroid capture

Want to mine an asteroid? Rather than travel to it with all their mining equipment, three Chinese scientists have proposed a better way. In a paper published today on the Los Alamos astro-ph preprint website, they have calculated the energy required to shift the orbits of the six thousand near-Earth asteroids and place them in Earth orbit for later mining. Of these, they found 46 asteroids that had the potential for such an operation, and two likely candidates for a space mission. One 30-foot-wide asteroid, 2008EA9, will actually be in the right place for this technique in 2049. As they write,

It can be seen that the velocity increment of the 2008EA9 is relatively small (-1.00km/s) and it will very close approach [approximately 645,000 miles] to the Earth in [February] 2049. Moreover the size of the NEO 2008EA9 is very small so that the capturing of it is relatively easy.

The real problem, of course, is adding that small “velocity increment” to the asteroid.
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Progress freighter launch fails

2:31 pm

The launch of a Progress freighter to ISS today has failed, with the freighter ending up crashing into Siberia.

This is very bad news for the station. Everyone in the space industry knows that with the shuttle gone, it will be a challenge to maintain supplies to the station’s the six-person crew. Losing just one supply ship will strain the station’s supplies, if not now in the long run for sure.

Worse, this is the first launch failure of the Soyuz rocket that puts both Progress and manned Soyuz capsule into orbit in more than eleven years. The next manned crew is scheduled for launch on September 21. Whether this failure will delay that launch remains unknown.

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NASA’s costs estimates too low for Congress’s heavy-lift rocket

9:55 am

Surprise, surprise! An independent analysis of NASA’s budget estimates to build Congress’s heavy-lift rocket, the program-formerly-called-Constellation, are untrustworthy and likely low.

“All three program estimates assume large, unsubstantiated, future cost efficiencies leading to the impression that they are optimistic,” the team said in its key findings. A risk assessment revealed the funding reserves projected for all three programs are insufficient, according to Booz Allen Hamilton. NASA has not disclosed its internal cost estimate for the Space Launch System. “Due to procurement of items still in development and large cost risks in the out years, NASA cannot have full confidence in the estimates for long-term planning,” the executive summary said.

This project is nothing more than Congressional pork. It will never get built. Sadly, it might waste a lot of money before it never gets built.

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Bigelow in negotiations to supply privately-built modules to ISS

12:59 pm

Bigelow Aerospace is in negotiations with both NASA and Japan to supply ISS with privately-built modules

The module could be rented out as an ISS storage unit, making the station less dependent on frequent resupply flights, says Hiroshi Kikuchi of JAMSS. To show that the modules are capable of safe, crewed operation, Bigelow is also negotiating with NASA to attach one to a US-owned ISS module.

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Craters, craters, everywhere

4:13 pm

Below the fold are two images released today, one from Dawn at Vesta and the other from Messenger at Mercury. What makes them interesting to me is that, though the surfaces of both Vesta and Mercury are crater-packed, there are definitely distinct differences between them that one can spot if you look closely, all highlighting the fundamentally different environments of both worlds.

First, the Vesta photograph. The image looks out past the asteroid’s horizon, showing clearly that this dwarf planet is not spherical, with the south pole depression that puzzles scientists just on the planet’s limb. The parallel long deep grooves that are associated with this depression can be seen on the right. Notice also that the inside walls of all the craters slope downward in a very shallow manner. This gives the impression that the impacts that formed these craters smashed into an almost beachlike sandy surface. Note too the that the center of some craters have what appear to be flat small “ponds,” a phenomenon seen by the spacecraft NEAR when it orbited the asteroid Eros. These ponds are not liquid, but are actually made up of fine-grained particles that settle in the hollows of the asteroid.
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NASA announces awards for three technology demonstration space missions

2:47 pm

NASA has announced three awards for technology demonstration space missions, all set to fly within four years. More details here.

The three missions are:

  • A solar sail demonstration mission, flying a sail 38 by 38 meter sail.
  • A demonstration of in-space laser/optical communications technologies.
  • The use of a high-precision atomic clock in space.

I especially like the solar sail mission because of its long range possibilities, though the other technologies would probably be put to practical use more quickly.

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The new commercial space companies question NASA contracting policies

3:02 pm

The new commercial space companies are challenging NASA’s new contracting policy.

The article covers the conflict that I described in this post, whereby NASA is abandoning the more flexible contracting approach used for the commercial cargo contracts of SpaceX and Orbital Sciences and going instead with the contracting system it used for all past NASA subcontracts.

The article is errs badly when it calls the new contracting approach that NASA wants to use “non-traditional.” It is instead the way NASA has been doing things for decades, whereby the agency takes full control of everything and requires contractors to fill out so much paperwork that the costs double and triple.

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New images from Opportunity

7:28 pm

Opportunity begins exploring the rim of Endeavour Crater, taking a bunch of new images . I especially like this one, of which I’ve posted a cropped scaled-down version below. The image looks across the 13-mile-wide Endeavour Crater to its far rim on the horizon. Note the haze. Mars very clearly has an atmosphere, even though it is far thinner than Earth’s. In the foreground are scattered rocks, ejecta produced from the impact that formed a smaller nearby crater now named Opportunity Crater.

Endeavour Crater as seen by Opportunity

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