Tag: engineering

Cosmic rays a threat to Mars travel

8:45 am

The uncertainty of science: New research using rats has found that cosmic rays might damage human brains during a long mission to and from Mars.

Radiation oncologist Charles Limoli and his colleagues at the University of California Irvine bombarded mice and rats with low-doses of ionized oxygen or titanium. These charged particles have similar energies to those of cosmic rays that can pass right through the shielding on spacecraft. The dosage levels that the researchers used were similar to what astronauts would be exposed to during a three-year round-trip mission to Mars, Limoli says.

The researchers looked at the prefrontal cortex, the brain region linked to decision-making, executive function, and long-term memory. They saw significant damage and inflammation in the brains of exposed animals as long as six months after the exposure. The radiation damaged the tiny branches on neurons that help transmit electric signals to the nerve cell body. This led to a loss in learning and memory. The exposed animals performed poorly on behavioral tests that measure intelligence, and they showed higher, constant anxiety levels.

Though the uncertainties here are enormous, the research here has essentially discovered the obvious. The radiation experienced during a long interplanetary voyage is unhealthy, and any interplanetary vessel for carrying humans on such a voyage must be designed with sufficient shielding to protect its passengers. That this research has proven that cosmic rays are a threat also means that providing a ship with a safe room where passengers can take refuge during solar storms is not sufficient. Cosmic rays are random and come at all times in an unpredictable manner. The research suggests that the shielding will have to protect the ship’s entire living quarters.

The payload weight requirements for any rocket that will launch the first interplanetary ships just went up significantly. This means that space stations we have been building (Mir, ISS, and Tiangong) are not even close to sufficient for interplanetary travel, and need significant redesign to make them work. This also means that human interplanetary travel will require cost-efficient heavy lift rockets such as the Falcon Heavy.

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Green Bank goes private

9:01 am

The competition heats up: The Green Bank radio telescope in West Virginia, having lost most of its government funding, has switched to a private model where they compete for customers on the open market.

[T]hey petitioned to retain a fraction of NSF funding and make up the difference with private contracts—a model then unheard of. Eventually, the NSF agreed to fund about 60 percent of Green Bank’s operations in 2017, tapering to 30 percent in 2018.

To add cash flow to that federal tributary, Green Bankers had to nail down private contracts. The 140-foot telescope, home to the biggest ball bearing in the world, will download data from the Russian Space Agency’s on-orbit radio telescope, RadioAstron, which will also hook up with the newer telescope to form a high-resolution array. The North American Nanohertz Observatory for Gravitational Waves has commissioned the flagship Green Bank Telescope to watch their network of pulsars for fingerprints of gravitational waves.

And Breakthrough Listen—a search for extraterrestrial intelligence—will look for the technological fingerprints of aliens. The project, funded by rich-guy Yuri Milner, will watch the sky 1,300 hours a year, debiting $2 million from Milner annually and depositing it into Green Bank’s coffers.

In other words, they are marketing the telescope to the open market, selling time to use it to whoever has a need. And apparently, there is a need, though I suspect operations at the telescope will have to become leaner and meaner and more efficient to stay in the black. Which is to the good.

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Opportunity to head into Endeavour Crater

12:47 pm

The Opportunity science team has decided to next take the rover into the floor of Endeavour Crater.

The gully chosen as the next major destination slices west-to-east through the rim about half a mile (less than a kilometer) south of the rover’s current location. It is about as long as two football fields. “We are confident this is a fluid-carved gully, and that water was involved,” said Opportunity Principal Investigator Steve Squyres of Cornell University, Ithaca, New York. “Fluid-carved gullies on Mars have been seen from orbit since the 1970s, but none had been examined up close on the surface before. One of the three main objectives of our new mission extension is to investigate this gully. We hope to learn whether the fluid was a debris flow, with lots of rubble lubricated by water, or a flow with mostly water and less other material.”

The team intends to drive Opportunity down the full length of the gully, onto the crater floor. The second goal of the extended mission is to compare rocks inside Endeavour Crater to the dominant type of rock Opportunity examined on the plains it explored before reaching Endeavour.

If it is the gully I think, it is the slope visible in the panorama I created for this rover update two weeks ago. The science team has named the mound they have been studying Spirit Mound. The ridge line, visible in the panorama and to the south of the rover in the overhead view provided in the same September 27 rover update, has been dubbed Wharton Ridge. It is also possible that the entrance gully is the gully to the south of Wharton Ridge. Based on the information NASA has provided, I am not sure.

Either way, I had guessed that they would work their way south to Wharton Ridge along the edge of the crater rim, and then retreat away from the crater floor to do more study of the interior crater rim. It appears they have decided that the rover can safely descend the slope to enter the crater floor itself, and they aren’t going to wait any longer to do it.

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Launches at Vandenberg remain suspended due to wildfire damage

11:06 am

It appears that though they had reported that the wildfires at Vandenberg Air Force Base had left the launch facilities undamaged, launches remain suspended due to necessary repairs.

Vandenberg officials have been tight-lipped about damage beyond confirming downed power lines in the area, despite unconfirmed reports in the local communities about a tracking station, weather sensor or other critical support equipment being ruined in the fire. Other unconfirmed reports mention damage to communication equipment.

ULA officials last said the launch would not occur before early October, but never released the targeted launch date as the Air Force began surveying damage and crafting a recovery plan. The Air Force remains mum about what was damaged or affected by the fires.

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SpaceX offers 10% discount for satellites launched on reused 1st stages

10:46 pm

In interview today for Space News, SpaceX’s president Gwynne Shotwell revealed that the company is only offering a 10% launch discount for any satellite launch that uses a reused Falcon 9 first stage, not the 30% price break she had indicated in March.

Though the interview also touched upon SpaceX’s September 1 launchpad investigation, it did not include anything significantly new. Shotwell readily admitted that the company did consider sabotage as a possible cause, but always considered it unlikely and right now has pretty much dismissed it. She also remains confident that the company will resume launches this year.

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Stratolaunch to use Orbital ATK’s Pegasus rocket

10:32 pm

The competition heats up? Vulcan Aerospace and Orbital ATK announced today that they are renewing their partnership, using Pegasus in conjunction with Stratolaunch to put satellites into orbit.

Under a multiyear “production-based partnership,” the companies said, Orbital ATK will provide “multiple” Pegasus XL air-launch rockets to be used with the Stratolaunch aircraft, which, when completed, will have the largest wingspan of any plane ever built.

With the Pegasus XL rockets, the Stratolaunch aircraft will be able to launch small satellites weighing up to 1,000 pounds, according to the firms’ joint statement released Thursday. Pegasus rockets already have done this kind of work: Orbital ATK has used them to launch satellites from the belly of its Stargazer aircraft.

This deal suggests to me that Vulcan Aerospace has a problem. It couldn’t find anyone to build a large rocket for Stratolaunch and this deal was therefore conjured up to paper over this problem. First , it appears that the reason Orbital ATK originally backed out was that they didn’t want to build the new rocket. Maybe they had engineering concerns. Maybe they were worried about cost or management. Regardless, they didn’t want to build it.

Second, using Stratolaunch with Pegasus seems pointless if the satellite weigh is still limited to only 1,000 pounds. That’s the payload capacity of Pegasus using Orbital ATK’s L-1011 Stargazer airplane. Why bother switching to Stratolaunch if the giant plane doesn’t give you any benefits?

Thus, it appears to me that what has happened is that Vulcan needed some rocket to use with Stratolaunch so that they could squelch the rising doubts about the company. This deal gives them that. It also probably gives Orbital ATK some extra cash to get them to agree to do it.

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Mars rover update: October 6, 2016

1:00 pm

Curiosity

Post updated. See last paragraph of Curiosity section.

For the overall context of Curiosity’s travels, see Pinpointing Curiosity’s location in Gale Crater.

Curiosity looking west, Sol 1475

Having moved south from Murray Buttes, the Curiosity science team has decided [see Sol 1473] that they will veer the rover to the southwest a bit, partly to check out some interesting features but also I think as part of a long term plan to find the best route through an area of sand dunes that blocks their path to the more interesting landscape at the base of Mount Sharp. The panorama above, created by me from images taken by the rover’s mast camera on Sol 1475, was taken to scope out this route, and is indicated below the fold in the overview released earlier this week by the rover science team and annotated by me to indicate the direction of this panorama as well as the rover’s present location. (Be sure to click on the panorama above to see it at full resolution.)
» Read more

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Success for New Shepard launch abort test

3:56 pm

The competition heats up: Blue Origin’s New Shepard capsule not only successfully rocketed away from its propulsion module and landed safely, the propulsion module unexpectedly survived today’ launch abort test and landed vertically as well.

This was the fifth flight of the propulsion module, which with the capsule will now be retired and placed on display.

Below the fold is the video of the entire test flight, including countdown and several long holds. The actual launch is at 1:06:19.
» Read more

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Redesigned Antares launch scheduled for Oct 13

6:45 pm

NASA and Orbital ATK have now set October 13 as the date for the first Antares launch in two years.

Though ISS is not short of supplies, this quote underlines the difficulty of the particular situation now.

While the space station has plenty of food, water, experiments and other provisions, NASA officials are eager for the Antares rocket to resume flights as all of the research outpost’s other servicing vehicles are facing delays.

SpaceX’s Falcon 9 rocket, which launches the company’s Dragon cargo craft, is grounded after a launch pad explosion Sept. 1, and Dragon resupply missions to the space station may not start up again until early next year.

The Japanese HTV cargo freighter was supposed to blast off Sept. 30 with several tons of supplies, including new lithium-ion batteries for the space station’s electrical system. But that launch has been delayed until at least December after Japanese engineers discovered a leak during an air tightness test in August.

And a Soyuz crew capsule that was supposed to launch Sept. 23 with three new space station residents will not lift off until at least Oct. 19 after Russian workers discovered a technical problem on the vehicle. The Soyuz delay will likely push back the launch of Russia’s next unpiloted Progress cargo freighter from Oct. 20 until late November or early December.

Even with numerous redundent methods for hauling cargo to ISS, it is still possible for them all to have problems all at once.

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Space letter wars in Congress!

6:34 pm

Turf war! A bi-partisan group of Congressmen, in response to an earlier letter by ten Republican senators questioning SpaceX’s ability to complete a thorough investigation of its September 1st launchpad explosion, have issued their own letter of support for the company.

In a letter to the heads of the Air Force, NASA and the Federal Aviation Administration, 24 members of Congress said that it was proper that SpaceX was leading the investigation. “Accidents are unfortunate events, and accident investigations should not be politicized,” wrote the bipartisan group led by Rep. Bill Flores (R-Tex.). “We encourage you to reject calls for your organizations to abandon established, well-considered and long-standing procedures.”

Ain’t democracy wonderful? It seems that SpaceX might have rounded up its own crony Congressmen to battle ULA’s crony Congressmen.

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Not sabotage!

6:55 am

This closer look at the circumstances behind the September 1 Falcon 9 launchpad explosion outlines why sabotage by a sniper is almost certainly not the cause of the explosion.

The rocket was destroyed about eight minutes before it could start its engines for the static test fire. The supposed sniper could have waited until first-stage engine ignition, which would have covered the sound of a shot. Even a suppressed rifle can be quite loud, and the passage of the bullet through the air would have generated a distinctive sound. As Elon Musk wrote on Twitter a while ago, his team did not come to that conclusion. “Particularly trying to understand the quieter bang sound a few seconds before the fireball goes off,” Musk tweeted. “May come from rocket or something else.”

The .50-caliber Barrett rifle has a maximum effective range of little over a mile. It would be extraordinarily difficult (albeit not impossible) for a trained sniper to get within rifle range of the launch pad, given the tight security at Cape Canaveral Air Force Station.

The article also notes that fuel tanks simply don’lt explode when you fire a bullet into them. Moreover, the problem came from the rocket’s second stage helium tank, and it would have been easier for a sniper to fire at the rocket’s first stage.

It was necessary for the investigation to look into this possibility, but it is also necessary to put the suspicion aside when it is found to be invalid. SpaceX had a rocket failure of significant importance on September 1st, and they need to uncover its actual cause in order to prevent it from happening again. Getting distracted by theories that don’t work will prevent them from doing that.

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Firefly shuts down

6:39 am

More details have been released by the shut down of operations at Firefly Space Systems.

They have furloughed all their employees, having lost one of their major investors. According to the company, the investor did not pull out because of the company’s litigation with Virgin Galactic, but because of its own internal considerations. The article also includes hints that Firefly might be one of the options that Vulcan Aerospace is looking at for building the rocket that its giant airplane Stratolaunch will launch.

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Curiosity moves on

8:55 pm

The Curiosity science team today put out press release summarizing what they have accomplished at Murray Buttes and what they hope to do next.

For those who have been reading my weekly rover updates on Behind the Black, most of this release will be old news. However, the release did provide the following interesting geological information that supplements what I have been reporting:

This latest drill site — the 14th for Curiosity — is in a geological layer about 600 feet (180 meters) thick, called the Murray formation. Curiosity has climbed nearly half of this formation’s thickness so far and found it consists primarily of mudstone, formed from mud that accumulated at the bottom of ancient lakes. The findings indicate that the lake environment was enduring, not fleeting. For roughly the first half of the new two-year mission extension, the rover team anticipates investigating the upper half of the Murray formation. “We will see whether that record of lakes continues further,” Vasavada said. “The more vertical thickness we see, the longer the lakes were present, and the longer habitable conditions existed here. Did the ancient environment change over time? Will the type of evidence we’ve found so far transition to something else?”

The “Hematite Unit” and “Clay Unit” above the Murray formation were identified from Mars orbiter observations before Curiosity’s landing. Information about their composition, from the Compact Reconnaissance Imaging Spectrometer aboard NASA’s Mars Reconnaissance Orbiter, made them high priorities as destinations for the rover mission. Both hematite and clay typically form in wet environments.

It also appears that the problems they had while doing the last drill hole were related to the electrical design flaw of Curiosity’s drill. It caused a short circuit this time, which is worrisome based on what I understand because this design flaw has the capability of shorting out the rover’s entire electrical system, ending the mission.

I will post a new rover update later this week, once I get back from Illinois.

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A detailed look at SpaceX’s Raptor engine

8:40 am

Link here. This story confirms for me a thought I had had while I watched Elon Musk’s talk last week outlining his proposed Interplanetary Transport System: SpaceX is still a good long way from actually building this rocket, since they have barely begun developing the rocket engine. They have made excellent progress in engine development, but they have a lot to do, with many pitfalls certain.

I therefore think that the company will be relying on its Falcon 9 and Falcon Heavy rockets, with their Merlin engines, for many more years to come.

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Sabotage?

9:08 am

The competition really heats up: The SpaceX investigation into the September 1 Falcon 9 launchpad explosion has apparently also included looking into the possibility that sabotage could have played a part.

As part of the investigation, SpaceX officials had come across something suspicious they wanted to check out, according to three industry officials with knowledge of the episode. SpaceX had still images from video that appeared to show an odd shadow, then a white spot on the roof of a nearby building belonging to ULA, a joint venture between Lockheed Martin and Boeing. The SpaceX representative explained to the ULA officials on site that it was trying to run down all possible leads in what was a cordial, not accusatory, encounter, according to the industry sources, who spoke on the condition of anonymity because of the ongoing investigation.

The building, which had been used to refurbish rocket motors known as the SMARF, is just more than a mile away from the launchpad and has a clear line of sight to it. A representative from ULA ultimately denied the SpaceX employee access to the roof and instead called Air Force investigators, who inspected the roof and didn’t find anything connecting it to the rocket explosion, the officials said.

To quote Sherlock Holmes, “When you have eliminated the impossible, whatever remains, however improbable, must be the truth.” In this case, it appears that they have eliminated this impossibility, though it is interesting that SpaceX felt compelled to consider it.

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