Monkeying About In Space

January 28, 2013 Tim Jones 1 Comment

With the news today that Iran has sent a monkey into space, it seems appropriate to post these pictures of the less than luxury accommodation occupied by chimpanzee Ham in an earlier era of space exploration.

Mercury-Redstone 2 Capsule (Photo: Tim Jones. Taken at California Science Center)

I checked out the Mercury-Redstone 2 capsule on display at the California Science Center while waiting to view the Space Shuttle last week.

Four year old Ham, who was an ape rather than a monkey, launched into space on 31st January 1961. He proved that beings similar to humans could survive and perform functions in space: to which end Ham was given a series of levers to pull on command (red, white, and black above).

It’s quite a mess in there:

Amazingly, the capsule Alan Shepard piloted to orbit three months later didn’t look that much different.

Ham beats the Iranian monkey on altitude, reaching 157 miles against the Iranian’s 75 miles – not that either would be aware of how high they were. The BBC report suggests the Iranian’s were testing the acceleration and deceleration of the rocket – although there’s the inevitiable ambiguity over why they’d want to do that, and the implications for weapons testing [monkey survives = warhead survives ?].

In related news, the U.S. National Institutes of Health announced this month they’d be stopping the use of chimpanzees for medical research; although I’m not sure where that leaves potential future space chimps.

Also of interest:

Guardian article on Ham http://www.theguardian.com/science/animal-magic/2013/dec/16/ham-chimpanzee-hero-or-victim?

Engineering, Science Centres, space, technology

Evocative Endeavour – Space Shuttle Endeavour at the California Science Center

January 24, 2013 Tim Jones 4 Comments

Space Transportation System (Shuttle) at the California Science Center ©Tim Jones — Space Transportation System STS-47 (Endeavour Space Shuttle) at the California Science Center.

Evocative Endeavour

I did kind of wish for a second or two today, staring up at the big, black, underbelly of Space Shuttle Endeavour – boxed away at the California Science Center in Los Angeles – that I’d made more of an effort to see she or her sisters performing live.

Am I getting all mushy and romantic about a spacecraft now? Well, maybe just a bit. My wife Erin said she felt unexpectedly moved after our visit. I’d set myself to appreciative-engineer-mode before I went in, but still felt like I was standing on the rim of the Grand Canyon for the first time; you’ve seen all the postcards and videos, and can’t imagine the real deal adding anything new – but it does. That’s twice I’ve been emotionally sucked in by an iconic cliché. Shocking.

Space Shuttle Endeavour at the California Science Center ©Tim Jones — Space Shuttle Endeavour at the California Science Center.

Objects are evocative. At one point I found myself back in my lab as a research student in Birmingham in 1986, hearing about the Challenger accident. Then I’m back imagining all those tiles, engines, doors, and windows flying apart.

And there on Endeavour is that area of wing leading-edge, damaged on Columbia by falling debris during launch, causing her demise on re-entry in 2003 (more on that in this earlier post).

First Impressions

There is of course plenty of engineering to appreciate, and science behind it to ponder. But my gut reaction is how big she is, the length of the cargo bay, and how….dirty . It looks like she’s been treated like some science fiction fan might treat an Airfix model of the Millennium Falcon: roughed up, artificially distressed – so it looks like the real thing. Except the distress, evidently manageable, is real.

Size perception is odd too. I’ve seen video of the shuttle during ascent (in fact you can see it in Matt Mellis’s movie/iPad App called ‘Ascent’), where the ‘body flap’ – that piece below the engine in the picture below – is vibrating violently; it’s positively oscillating. The flap looks small and flimsy on the film, but it’s a huge construction; the forces must be tremendous.

Cargo Door Hinges ©Tim Jones — Cargo Door Hinges

Engines

RS-25 Space Shuttle Main Engines (SSME), Gimbal area. ©Tim Jones — RS-25 Space Shuttle Main Engines (SSME), Gimbal area

Gimbal area close-up ©Tim Jones — Gimbal area close-up

Thrusters

Orbital Maneuvering System (OMS) Pods with thrusters ©Tim Jones — Orbital Maneuvering System (OMS) Pods with thrusters

Tiles

The famous tiles, part of the Shuttle’s Thermal Protection System (TPS), are unmistakable. Designed not to ablate like the heat shields on the Apollo capsules, tiles do suffer wear and damage, and some had clearly been replaced with new ones for display.

The complexity and variation of tile design is striking. If you think tiling round the bathroom wash-basin is tricky, take a look at the area round the main engine gimbals and thrusters of the Shuttle. No wonder maintenance costs were high.

Tiles (part of Space Shuttle Thermal Protection System TPS) ©Tim Jones — Tiles (part of Space Shuttle Thermal Protection System TPS)

Tiles (part of Space Shuttle Thermal Protection System TPS) Close-up ©Tim Jones — Tiles (part of Space Shuttle Thermal Protection System TPS) Close-up

Earthquake Protection

Several sliding bearings, or seismic isolators, sit between the Shuttle and its supporting pillars, insulating Endeavour from the perils of Los Angeles’ earthquakes. The idea is the Shuttle rocks around harmlessly until the shaking ground settles down.

Endeavour is mounted on Seismic Isolators to protect it from earthquake damage. ©Tim Jones — Endeavour is mounted on Seismic Isolators to protect it from earthquake damage.

Seismic Isolator Bearing Surfaces. ©Tim Jones — Seismic Isolator Bearing Surfaces

Visiting

We saw Endeavour in temporary accommodation; it’s destined to be mounted vertically in a custom-designed building. That said, the exhibition as it stands doesn’t feel temporary, and the associated display areas and accompanying audio-visuals describing California’s particular role in the Shuttle story and showing off various artifacts from the program – including, importantly, the Shuttle’s WC or ‘space potty’, are excellent.

Entry to the California Science Center is free, but there’s a very reasonable $2 entry charge or ticket booking fee to see Endeavour.

Entrance to Endeavour Area ©Tim Jones — Entrance to Endeavour Display Area

Simulated Mission Control ©Tim Jones — Simulated Mission Control

Space Shuttle Wheels ©Tim Jones — Space Shuttle Wheels

Display Area ©Tim Jones — California and artifacts display area

Parting Impressions

Even as we celebrate, the Space Shuttle program is criticised, particularly around issues of cost and safety, but also the scope of its achievements. As always, it’s easy to find fault in hindsight, and judge historical decisions by the political and economic expedients of the present day. Personally, I reckon we’d be in a much sorrier state had the program not gone ahead. The Shuttle was the workhorse behind the International Space Station, the full learning from which I suspect has yet to be converted. And Endeavour personally, so to speak, enabled the repair of the Hubble Space Telescope.

The Hubble Space Telescope can see clearly now thanks to Endeavour. (Model at Cal.Science.Center) ©Tim Jones — The Hubble Space Telescope can see clearly now thanks to Endeavour. (Model at Cal.Science.Center)

NASA is at a turning point, collaborating more closely with private partners and, most recently, other nations on its manned space program. While the arrival of new entrants, working methods, and relationships are culturally refreshing, surely much of the knowledge and expertise behind them has its roots in the Shuttle and related programs.

Hopefully this note’s been short and sweet. There’s no point my repeating loads of technical and historical information you can get from many sources: not least the NASA and California Science Center websites, which, like Endeavour, are both worth a visit.

ALL PHOTOGRAPHS BY TIM JONES

Of Related Interest on Zoonomian

Matt Mellis Shares 30 Years of the Space Shuttle at the London Science Festival

astronomy, events

Jupiter Conjunction with the Moon 21st January 2013

January 22, 2013 Tim Jones 5 Comments

Jupiter this afternoon is moving in for the closest line-of-sight conjunction with the moon you’ll see until the year 2026.

Moon with Jupiter in daylight. 15.30 (PST) from Los Angeles. © Tim Jones

Jupiter is very bright and easily viewable in the daytime – especially with binoculars; the problem is you can never find it. Because it’s so close to the moon today, that’s no problem: find the moon and you’ve found Jupiter. This is my first pic of the day. I’ll update with new ones every few hours as Jupiter moves in to closest approach and the Jovian satellites start to appear. I have only a reasonable telephoto with me, not a telescope, but we’ll see how it goes.

Get out there now with those binocs!

Moon with Jupiter in Daylight 16:30 (PST) Los Angeles ©Tim Jones — Moon with Jupiter in Daylight 16:30 (PST), 21.01.2013, Los Angeles ©Tim Jones

Moon with Jupiter 17:00 (PST) Los Angeles — Moon with Jupiter 17:00 (PST), 21.01.2013, Los Angeles ©Tim Jones

IMG_0499_2 — Jupiter and Moon, 17:25 (PST) Los Angeles, ©Tim Jones

Jupiter and Moon, 17:45 (PST) Los Angeles. ©Tim Jones

Jupiter and Moon, 17:55 (PST), 21.01.2013, Los Angeles. ©Tim Jones — Jupiter and Moon, 17:55 (PST), Los Angeles. ©Tim Jones

Jupiter & Jovian Moons, 17:55 (PST) ©Tim Jones — Jupiter & Jovian Moons, 17:55 (PST), 21.01.2013, Los Angeles, ©Tim Jones

Jupiter and Moon, 18:41 (PST) Los Angeles. ©Tim Jones — Jupiter and Moon, 18:41 (PST), 21.01.2013, Los Angeles. ©Tim Jones

Moon and Jupiter, 18:45, 21.01.2013, Los Angeles ©Tim Jones

Moon, Jupiter, Hyades & Pleiades clusters 18:49 (PST), 21.01.2013, Los Angeles. ©Tim Jones — Moon, Jupiter, Hyades & Pleiades clusters 18:49 (PST) Los Angeles. ©Tim Jones

You don't need the Hubble Space Telescope to have fun with the sky... — You don’t need the Hubble Space Telescope to have fun with the sky…

Moon and Jupiter, 19:21 (PST), Los Angeles. ©Tim Jones

Position of Jovian moons 19:45 (PST) Starry Night software (note: this just to show moon positions; the image of Jupiter here is from the software; my kit isn’t that good).

Jupiter and Moon, with the fairy-lights on and Orion rising. What more could you want?

That’s about as close as it will get: 30 minutes of arc, or a Moon’s diameter. Some folks in the Southern Hemisphere will see Jupiter completely disappear behind the moon – an occultation. But that’s me done for the evening. Happy stargazing!

animals, biology, Botany, nature

Busy Bees

January 18, 2013 Tim Jones Leave a comment

Here are a few shots I took this afternoon of bees feeding on/pollinating one of the many species of Aloe that populate the Huntington Gardens.

The bees burrow and completely disappear inside the tubular orange flowers.

These two shots show the pollen baskets:

Pollen baskets are attached to the hind legs by a single hair

Bee entering Aloe flower with pollen baskets

Aloe plant at Huntington Gardens © Tim Jones — Aloe Plant at Huntington Gardens (San Marino)

Humming Bird Feeding on Aloe (©Tim Jones) — These guys get a look-in too

Uncategorized

To Catch a Humming Bird

January 9, 2013 Tim Jones 1 Comment

It’s no secret humming birds beat their wings fast, but it’s also nice to catch one in the act.

I snapped this Allen’s Hummingbird (Selaphorus sasin) yesterday at a shutter speed of 1/800th second (0.00125 s) and his wings are still a blur.

Humming birds can beat their wings at up to 200 beats per second – the wing completing its travel in 0.005 s. I reckon the blurred area above represents about a quarter of a full beat, which is just what we’d expect if this guy were flapping near the max. (i.e. 4 x 0.00125 = 0.005).

Look how the body stays almost perfectly still; it reminds me of those stories about being able to balance a coin on the bonnet of a Rolls-Royce. There is a slight wobble: if you compare his head to his foot (and the pictures below where he’s settled down) the head shows a slight shimmer.

With the sun catching him like that, we’re also getting a good demonstration of the iridescent color effects humming birds exhibit due to interference of light within the microstructure of their feathers.

Here are a few more pictures of the same bird:

Art, Engineering, Experiments, Fun, Materials

Musings on Structural Gingerbread

January 3, 2013 Tim Jones 1 Comment

It’s still the holiday season, so no apologies for doodling on about gingerbread, which, as it turns out, can be pretty strong stuff – if a bit bendy.

Cue my wife Erin’s first attempt at a gingerbread house (above). Pretty good, huh? The heat from the incandescent fairy lights has kept it from turning mushy, and nicely spiced up the room at the same time. The house is only eight inches tall, but prompts the obvious question: “How high can you build with gingerbread?”

A structural analysis of a full-on house with walls, windows and doors is too tall an order, even with finite element techniques, so I settled on calculating a ballpark maximum height based on standard engineering equations for a free-standing gingerbread column.

There’s no wind blowing through our lounge, so we can ignore sideways forces and focus on the two likely failure modes a column of gingerbread might suffer – just because of its own weight as it gets taller, i.e.:

(a) the construction materials can disintegrate under their own weight: a function of compressive strength, or

(b) the column can buckle, which is more related to the material’s elastic, or tensile properties.

The heights at which these two failures occur can be found from, respectively:

$H_{max} = \frac {P_f} {\rho\times g}$

$H_c =\left(\frac{9 E I}{4\rho g A}j^2\right)^{(1/3)}$

where $H_{max}$ =column height at compressive failure (m), $P_f$ is the failure pressure (N/m²) = compressive strength of the gingerbread, g=gravity (9.8 ms^-2), and $\rho$ is gingerbread density (kg m^-3). And for buckling: $H_c$ is the critical height, E is Young’s Modulus of elasticity calculated as tensile stress/strain, I is the Area Moment of Inertia³, and $j\approx 1.8663$ is a factor called a Bessel function, used to solve this type of equation (Ref.2)

Using published gingerbread properties data¹ (amazingly, there actually are some) for compressive strength and tensile stress/strain, I calculated values of:

$H_{max} = 50metres$

$H_c=3metres$

(Workings in box below if you’re interested.)

which essentially means a gingerbread column will start to lean over and buckle sideways long before the gingerbread breaks up through compression under its own weight (I used an arbitrary but realistic 20 cm column diameter). You might think there’s no reason why a uniform, vertical, column would start to lean, but in real life the weight distribution is never uniform and, if the column is sufficiently slim, a turning moment will establish and drive a progressive buckle.

So if you’re going to build a gingerbread house out of free-standing columns, better stop at 3 metres.

Buckling is clearly the limiting factor, but the 3 metre figure is based on a relatively small 0.2m column diameter, and buckling is particularly sensitive to cross-sectional area (whereas compressive fracture of a column under its own weight is independent of area). Also, most real buildings are more complex than a bunch of pillars, and I’d expect the right combination of interconnecting members building up from a broad foundation could reduce buckling potential, making a full-size gingerbread house a reality.

Indeed, the Guinness Book of Records ‘Worlds largest gingerbread house’ is 18.28m (60ft) on a 13.86m by 10.8m base; but closer inspection shows it’s built around a steel frame that presumably keeps incipient buckling in check. But then it’s more of a gingerbread and steel house – a bit of a con really.

Anyhow, our room’s about 3 metres high, so nothing stopping a more ambitious project next year: Empire State Building or Cathédrale Notre Dame ?

Workings

Note that for compressive failure of a column under its own weight, the area of the column A (m²) cancels and isn’t relevant: i.e $P_f = \frac {m\times g}A$ so, $P_f * A = H_{max} A\times \rho\times g$ and $H_{max} = \frac {P_f} {\rho\times g}$ as above.

I couldn’t measure my own gingerbread density easily (although it for sure floated in water, so < 1000 kg m^-3), and used a middle value of 700 kg m^-3 from this unlikely study by students at the University of British Columbia (UBC)¹. In addition to the UBC data for $P_f$ of 346 kPa, I measured my own value for $P_f$ by pressing a sample (squirrel-shaped in this case, but taking the narrowest foot area as 1*10^-4m²) vertically downwards onto a balance and recording when it crumbles.Still intact when the balance read 6kg, I took my $P_f$ to be at least 6 * 9.8 / 1*10^-4, or 588 * 10³ N/m² (588 kpascal kPa). In fact, for compressive strength, my numbers and the published data are conservative, as in neither case did the gingerbread actually fail at these values. So:

$H_{max} = \frac {346\times 10^3}{700\times 9.8}=50 m$ (UBC data)

$H_{max} = \frac {588\times 10^3}{700\times 9.8}=85 m$ (my gingerbread)

Whether it buckles first, at a lower height, depends on the elasticity of the gingerbread and the slenderness of the column: i.e. the ratio of column area to length.

The height at which buckling occurs can be found from Cox & McCarthy²:

$H_c =\left(\frac{9 E I}{4\rho g A}j^2\right)^{(1/3)}$

where $H_c$ is the critical height for buckling, E is Young’s Modulus of elasticity calculated as tensile stress/strain, and I is the Area Moment of Inertia³.

To calculate $H_c$ , I chose an arbitrary column diameter of 20 cm diameter, and used stress/strain data from the Canadian study¹ to calculate E = 9790 kPa; i.e. 219/0.02237 (the change in dimensions of my squirrel under tension are too small to measure with the kit I have).

The Area Moment of Inertia for a circular cross-section $I = \frac{\pi}{4} r^4$ , which for a 0.2m dia. column gives $I= 7.85\times 10^-5$ . And ( $j\approx 1.8663$ , is the appropriate Bessel function of order -1/3 (Ref.2) Note: in the source equation, weight density is specified; hence g added here.) So:

$H_c =\left(\frac{9\times 9790\times 10^3\times7.85\times 10^-5}{4\times 700 \times 9.8\times \pi\times 0.1^2}\times1.8663^2\right)^{(1/3)}$

$H_c = 3 metres$

A more complex structure would best be assessed computationally using finite element analysis, but I’m not getting into that.

References
1. ‘Building with gingerbread: Engineering students put holiday delight to the test’ refers to ‘Structural Analysis of Gingerbread. Engineering Design Project Term 2’ by Mercedes Duifhuis and Sean Heisler (pdf)
2. The Shape of the Tallest Column. Steven J.Cox, C.Maeve McCarthy, Society for Industrial and Applied Mathematics. Vol29,No.3. pp.547-554. (Also see Wikipedia page on buckling.)
3. Engineering Fundamentals efunda.com/math)

Of related interest
How to create the perfect sand castle Nature Scientific Reports 2, Article number:549, doi:10.1038/srep00549

Communicate Science

Monthly Archives: January 2013