May 25, 2004



Dark Sky Station

October 9, 2016
Journal of Captain Marvin Orr
Day 1

I was encouraged to keep a journal during my stay at Dark Sky. The eggheads think a journal helps aeronauts handle isolation. I really don't think it'll be that big of a deal. I'll be alone at the station for just 9 days before another crewmember is scheduled to join me. Three months ago I spent 11 days alone in an isolation chamber. I got bored, but I didn't go crazy. At Dark Sky I'll be too busy to get bored. I'll be putting in 11-hour days, and when I'm not working there's always television, and the Internet.

Whether I need the journal or not, I'm a team player, even if the game is solitaire. So I'll keep the journal.

I arrived early this morning on the Dakota airship. The ride was a bit rough at first . Those airships can get buffeted around pretty badly below 50,000 feet if the weather is not perfect. And the weather wasn't anywhere near perfect. They launched me because the station had been unmanned for a month and there was some maintenance that couldn't wait any longer if the station was going to remain operational.

The Dakota was automatically piloted. I've got some operational training on that model, but I was happy to let the craft guide itself. It even handled the docking. Once docked I pushed a large cargo container into the airlock and shut the first door. My ears popped as the pressure in the lock equalized with the station. The second door opened and I pushed the cargo through. When that door closed I heard the Dakota undock quickly. I didn't take time to watch it leave, I immediately went to the head.

I had been onboard the Dakota for 19 hours and it was good to be able to get out and stretch and use a real restroom. I didn't delay long however. Inside of ten minutes I was back at the airlock preparing for an EVA.

Inside my cargo container was a specially fitted EVA suit. This suit had been designed so that I could get into it without help. All was well except for the zipper on the inner liner. That zipper runs from butt to neck and I was supposed to be able the do it myself. I found a hanger in the cargo bin, hooked the zipper and pulled it up. Small victories.

During suit-up I got a call from Vandenberg. They were just getting audio confirmation of what they already knew that I had arrived and was preparing for EVA.

It took every bit of an hour, but I got the suit on. The suit performed a quick diagnostic and gave me a green light to go outside. I grabbed my toolkit, strapped it around my waist so that it was handy at my hip, and stepped into the airlock.

Inside the airlock I attached a safety line. In case of sudden loss of pressure I didn't want to be blown out into space. Actually, SOP demands that you always have at least one attached safety line during an EVA or within the airlock. I slowly depressurized the lock (very little oxygen is lost) and then opened the outside door. Just past where the Dakota had docked was a small catwalk that climbed up the side of the station and onto the roof.

How can I describe it? You can see the whole world from the top of the station. It was midmorning directly below, so only about a quarter of the world was blue with light. At 100,000 feet the sky above is always black with steady points of stars. It is a beautiful sight. I heard that Senate appropriations demanded that the station be capable of conversion to a civilian observatory. Smart. It really is quite a view.

The station itself looks like a giant cross or "X." Each of the four legs of the cross is a helium pontoon that runs out over a mile away from the central station. The most critical problem was about a quarter mile out onto pontoon "C." I reattached my safety line to a cable running the length of the pontoon. I walked out to find the problem.

I saw it when I got within twenty feet. The pontoons are made of a stiff composite fabric that is extremely thin and light, but very tough. Tough or not, if it gets hit by a micrometeor, it will rip. Inside the tear I saw that we had lost just one helium cell no big deal. I could simply add a little more helium to all the other cells in the pontoon to make up the difference. That I could do inside the station. Out there I used duct tape to hold the rip in place while I patched it with epoxy.

Once I was finished I returned to the station. I was dead tired from the trip and the exertion of the EVA. I hit the bunk and fell asleep quickly.

The low gravity seems to be affecting my sleep cycle. I woke after about four hours of sleep, long before I was scheduled to start the day. So I sat down to write this.

My second day will be spent working on the ground surveillance gear. The thermal camera is on the blink.

Posted by Stephen Gordon at May 25, 2004 04:10 PM | TrackBack
Comments

Cool!

Would gravity really be noticeably lower at a "mere" 100,000 feet up?

Posted by: Phil Bowermaster at May 25, 2004 05:15 PM


Nicely done. How much research did you do for the technical details? What is the time setting?

When can you put a spot on TV to counter the Kerry ads about Bush's priorities?

Posted by: Kathy at May 26, 2004 06:58 AM

About the only research I did was read the article that Phil pointed to in "Better All The Time #8."

I did email a physicist about the gravity question. He didn't write back before I was ready to post, so I just guessed that gravity would be noticeably lower at 100,000 feet. I could be wrong about that.

We fly commercially all the time at 30,000 feet, and when we get up to move around the cabin we aren't jumping around like on the moon, but my guess is that gravity decreases exponentially as you move away from an object. In other words, the loss of gravitational pull at 90,000 feet is much more than 3x the change between 30,000 feet and sea level.

All of this makes me wonder if it would be possible to have a "Dark Sky" type station in the atmosphere of a gas planet at a stable altitude that would give 1 G. This probably would not be possible with a planet as large as Jupiter or Saturn (probably too much gravity even in the outer atmosphere), but again, I'm just guessing.

Posted by: Stephen Gordon at May 26, 2004 08:20 AM

Gravitational force is an r^2 function measured from the center of the earth. So you'd weigh about 1% less on the station.

Posted by: Karl Gallagher at May 26, 2004 12:27 PM

Karl:

And that wouldn't be enough to notice.

Posted by: Stephen Gordon at May 26, 2004 12:42 PM

More quibbles: if you're standing in sunlight, the stars are invisible even in an airless sky due to the glare of sunlit objects around you. Practical example: grab one of those million candlepower spotlights that plugs into the dash on your car, step outside on a dark night, and shine the light on your face from arm's length. Even if you don't look into the light, you won't see any stars. (Other than afterimages from the lamp :)

If it's midmorning, the sun will be shining on everything below you quite uniformly- only near sunrise or sunset could you see the terminator sweeping across the land below.

At 100,000 feet, the balloons are shielded from micrometeorites almost as well as at the surface- most of the incoming flux gets stopped at far higher altitude. Only much larger objects make it as low as 100 kft, and a strike from one of those would be catastrophic- and tremendously unlikely.

The balloon fabric would be very thin, very supple, and only stiff if holding internal pressure. At such high altitudes, a tiny pressure difference would make for a substantial increase in density, so the dP would be kept very low. Think of a dry cleaner's bag held open over a candle- that's the sort of gossamer structure you'd see.

Posted by: Doug Jones at May 26, 2004 02:13 PM

For the record, the equation is Force (weight) = [mass of subject] * [Mass of Earth] * [Universal Gravitational Constant (G)] / [Distance from Earth's center]^2. Working this out for a 100kg (220 lb, give or take) Aeronaut at mean sea level (= 6.38 * 10^6m radius) and at 100,000ft AGL (= 6.41 * 10^6m radius) gives values of 220lbs on the ground and 218lbs at Dark Sky station.
While I'd love to lose any weight I can in this manner, I don't think I'd really notice the equivalent of emptying my pockets...

On a side note, though, why is it whenever I look at the concept proposed by JS Aerospace I can only think of two dramatic alternatives? Either it puts me in mind of Nick Fury's (TM) S.H.I.E.L.D. (TM) HeliCarrier (TM) (Marvel Comics (TM)) or of a mutton-chopped, steam-era Zepplin captain shouting "Damn the aerial torpedoes! Full speed ahead!" (William Gibson, call your office! to coin an Arcturan phrase)

Posted by: Michael Sargent (EJG) at May 26, 2004 02:15 PM

Doug:

On quibble 1: Do astronauts in orbit not see stars if the earth is shining reflected light below them?

On quibble 2: If you can see half the earth below you (something that, I admit, is not possible at 100,000 feet) wouldn't you always see a terminator unless it is exactly midday or midnight?

On quibble 3: No doubt a "Dark Sky" station would be more protected from meteors than, say, the ISS. But it would not be 100% safe.

On quibble 4: For purposes of this little story I've imagined a material that is extremely light, thin, and yet stiff and tough. I'll bet you a soft drink that by 2016 such a material will exist.

Posted by: Stephen Gordon at May 26, 2004 03:05 PM

The Extropy list has been talking extensively about this:

http://bbs.extropy.org/index.php?board=69;action=display;threadid=58707

Posted by: Reason at May 26, 2004 03:14 PM

Hmm... a military station, then, futzing with surveillance cameras and getting a call from VAFB ?
A civilian space launch platform would be much nicer.

Posted by: kert at May 27, 2004 06:18 AM

Kert:

True. But as the referenced article pointed out, this is being developed for military purposes.

There are treaty obstacles to developing space for military purposes. Since 100,000 feet isn't technically space, it slips through the loophole.

It's not hard to imagine something like this being developed and placed over international waters within sight of the middle east - or directly over Iraq.

Posted by: Stephen Gordon at May 27, 2004 06:39 AM

We managed to catch an image of Venus on Away 17 with a simple handheld video recorder. Stars are visible up there. Since our eyes are much more logarithmic in their response to light, I imagine we will be able to see the brighter ones moderately well.

The DSS is not being developed for military purposes. We have not accepted any military contracts involving DSS. The lower Ascender is being built on Air Force money, but they are mostly interested in proving it is possible to do what we say we can do. We have retained rights to our design and we are mostly interested in commercial prospects.

Regarding puctures, we intend to have an automated cell replacement system. The 'pontoons' are actually two layers right now. The outer layer is a load bearing fabric. The inner layer is the one that is supposed to prevent the Helium from getting away. We should be able to roll up the inner ones and deploy new ones if damage occurs. A small hole in the outer layer would be something to fix with a needle and thread. 8)

Neat story though. It reminds me that we will have to make the ride up on the Ascender a more pleasant trip.

Posted by: Alfred Differ at May 28, 2004 04:10 PM

Okay, Stephen, I'll return the volley-

> On quibble 1: Do astronauts in orbit not see
> stars if the earth is shining reflected light
> below them?

Nope. If you have a substantial amount of fairly reflective surface exposed to sunlight, and you can see it, your dark adaptation will go away. I vaguely recall that one of the Apollo astronauts actually managed to find a few minutes to stand in the shadow of the LM, and did get to see Venus, but not any stars. Damned if I can find a reference for that, though. Try it yourself- stand on a pitcher's mound of a stadium with one bank of lights on at night (to make it easier to pick a direction with less glare) and try to see the stars. Then consider that the lights are less than 1% of the intensity of sunlight...

> On quibble 2: If you can see half the earth
> below you (something that, I admit, is not
> possible at 100,000 feet) wouldn't you
> always see a terminator unless it is
> exactly midday or midnight?

Only if you are at substantial altitude- at 400 km, for example, the horizon is about 2300 km away, and about 20 degrees below horizontal. If the sun is more than 20 degrees above the horizontal, the terminator will be over the horizon. At 30 km altitude, the horizon is 5.5 deg below horizontal, and so if the sun is over 5.5 above one horizon, the terminator would be right at the other.

> On quibble 3: No doubt a "Dark Sky" station
> would be more protected from meteors than,
> say, the ISS. But it would not be 100% safe.

True, but as a plot device, even a minor impact is implausible. Getting zapped by a sprite out of a thunderstorm below might be much more likely, and a truly exotic element of the environment at 100 kft... electrical arcs in low density air are more like a neon sign discharge than a lightning bolt. This could be interesting!

> On quibble 4: For purposes of this little
> story I've imagined a material that is
> extremely light, thin, and yet stiff and
> tough. I'll bet you a soft drink that by
> 2016 such a material will exist.

It won't. You can have light, thin, tough, and strong, but stiffness requires thickness- thus the great difference in rigidity of a hollow tube vs a solid rod of the same mass/length. Sandwich structures can be light, stiff, and strong, but aren't thin. This is structures 101 stuff, not subject to superduper materials advances- even diamond can't be both thin and stiff.

Posted by: Doug Jones at May 28, 2004 06:08 PM
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