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Bigelow Aerospace Article; Life in a Box

Published by Sigurd De Keyser on Tue Dec 12, 2006 9:57 pm
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Space Colony

By Maijinn Chen Payload Development & Integration Bigelow Aerospace; One afternoon back in July Mr. Bigelow called his payload team into his office and proudly showed five dirt-filled containers. Not just any dirt. This dirt contained ants — predecessors to a “space colony” of bugs destined for lower Earth orbit.

“I went on vacation and in my spare time dug up an ant hill,” Mr. Bigelow nonchalantly told his team. He described how he manipulated their environment with twigs, new dividers and openings, and how he spent vacation hours in his Montana ranch observing the resourceful ants adapting to these changes. What could they accomplish, he asked the team, given enough options in a microgravity environment?

It is this kind of keen curiosity that has been the driving force behind the design and development effort of the Biobox, a pressurized payload to be launched in early 2007 aboard the Bigelow Aerospace spacecraft, Genesis II. The payload has been successfully built and tested, and is mounted in the spacecraft waiting for its scheduled flight.

More than for any practical applications, Genesis II Biobox was an in-house experiment borne out of our joy for learning: learning about insects and anticipating how they would behave in microgravity, and learning how to provide life support systems that would not overburden the onboard infrastructure — all the while hoping that we could involve the public in our adventures.

With the Biobox, the design team experienced firsthand the complexity involved in creating an autonomous habitat to support even the simplest life form. It serves as a wake-up call for the immense task ahead, as we work toward supporting life in space: human or otherwise.

The Right Stuff

Krogh’s Principle states that for a large number of biological problems, there will be some animal of choice on which it can be most conveniently studied. Therefore, one of our first design tasks included careful selection of our “astronauts” — animals that could survive such harsh conditions as minimal food and water, a low-pressure environment, and launch forces of up to 8g, or eight times the force of gravity.

Thus began what our Biobox builder John LaValley calls the AARP — Arthropod Astronaut Recruitment Program. And who better to start the recruitment process than the hardy cockroach?

We’ve all heard about cockroaches capable of surviving a nuclear war. Could they survive a trip to space? We tested and flew roaches on Genesis I earlier in the year, and Madagascar giant hissing cockroaches again made the cut for the second mission. In one of our many ground tests, we subjected these “Maddies” to a vacuum environment for two hours and found that they could twitch back to life within an hour.

We enlisted Sable Systems International — a local team of experts in arthropods and respirometry equipment — to help narrow down our other selections and obtain enough specimens for ground testing and flight.

For ants we selected Pogonomyrmex californicus, a local ant species from the Southwestern United States. We were able to obtain some queenright colonies, each with a population of up to 250 ants. With a queen, we hope the colony we fly can be self-sustaining and last for more than three years. Otherwise, without a queen and a brood, the colony would lose its purpose and die within months.

Scorpions were the final recruits, thanks to their ability to drastically lower their metabolic rates to 25 percent of those in the general insect population. Some species can live on just one meal a year and use little oxygen. At first, fellow Bigelow Aerospace employees caught local species in their backyards for observation. Eventually, we chose the South African flat rock scorpions, Hadogenes troglodytes, for flight. These scorpions are long-lived, and come from very arid areas where they live in dry rock crevices. They are also relatively docile and easy to handle despite looking large and scary. In our ground lab we have been feeding them baby Maddies, watching in awe as they held the roaches with their claws and chowed them down like hamburgers.

With our arthroponauts chosen, we could begin the task of creating a space habitat capable of supporting a variety of life forms with different social behaviors, as well as separate environmental and dietary needs. But first, these animals needed to go through rigorous ground testing to find out if they had the right stuff.

Under Pressure

We placed these animals in sealed environments to collect data on oxygen consumption, carbon dioxide emission, temperature and humidity; built terrariums decorated with rocks and tree bark; tested them for interspecies compatibility; froze them; fed them water-retaining crystals, dog food, rodent food and meal worms; made them climb lattices of strings; and tagged them with paints and rhinestones. Our arthroponauts amazed us with their ability to adapt and survive under pressure.

In one of the tests, Sable Systems subjected all the animals to below-normal air pressure at five PSI, and observed the short- and long-term effects. We found that although life at five PSI was bearable, the survival rate of insect offspring was drastically lowered. Newborn roaches, for instance, were dead or nearly dead at birth at five PSI. This drove our requirement to create a pressurized habitat with at least nine PSI. We also found that the insects lost water a lot more readily in below normal pressure, as they accelerated their “breathing” or gas exchanges. Since most insects won’t be able to withstand water loss beyond 25 to 30 percent of total body mass, a regular water supply is needed to prevent them from dying of desiccation. Lastly, we found that food spoiled readily in a sealed, low-pressure environment. This signaled to us the importance of inhibiting fungal growth on the food, along with proper humidity control.

What Happens in Biobox Stays in Biobox

Armed with test data, the payload team conceived of the Biobox as a cylindrical pressurized enclosure with dome end caps, capable of withstanding the large forces created by the pressure within. This will be important when Genesis II experiences the vacuum of space during the initial phases of the launch. “It’s like trying to make a soda-pop bottle contain a bomb blast,” said Adam Kessler, Biobox’s main designer. “The forces inside are literally like hanging a Volkswagen Bug from the dome on either end of the Biobox. We definitely learned about the limitations of the available materials and processes at our disposal.”

The Biobox habitat is divided into three chambers. Two that are partially connected are where the “Maddie” roaches and the scorpions reside. The ants have the third chamber all to themselves, but share the air with their fellow Biobox residents.

We designed an air management system that allows scheduled exchanges of Biobox air with that of the main vehicle cabin, allowing the Biobox to regularly receive fresh oxygen and purge CO2 and other trace contaminants. Humidity is removed from the expelled air before it enters the vehicle cabin.

For food and water delivery, we designed primary and secondary motorized assemblies that would allow for scheduled feeding of green jellies and water-retaining gel, sources of food and water for both the roaches and the ants. In six months, we will also be able to open up new supplies of food and water. We further supplemented the menu with irradiated rodent food bar for the roaches and Kentucky bluegrass seeds for the ants. The only food vulnerable to aggressive mold attack is the food bar, so we made sure it is flooded with lights in the deep ultraviolet range that act as a germicide.

In ground testing, we found that the roaches could generate a considerable amount of feces. Our solution to waste management was to integrate a collection chamber with the air output. As the air is pumped out of the Biobox during an air exchange, the feces will float into the chamber with the aid of circulation fans and stay trapped within the multiple layers of coarse mesh filters.

We are also providing heating pads to create areas of warmth for the insects, should the vehicle temperature drop when it is traveling around the dark side of the Earth. For instance, we have placed a heating pad in the ant chamber close to a water source. This will provide an area of 30° to 32° C suited to the queen ant and her brood.

We also realized that we needed to uniquely tag all the insects to ready them for camera viewing. Besides performing a considerable amount of bug wrangling, we had to experiment with a lot of different glue bases and tagging methods to find one that would stick to their exoskeleton without causing harm. “Who would have thought an episode of the America’s Next Top Model would come in handy, but it did give us the idea of differentiating them with colored rhinestones,” our resident biologist, Jackie Wynn, recalls. “Our scorpions and roaches got only the best: Swarovski crystals. After all, we are in Vegas!”

What would be the point of doing all this if we couldn’t collect data from the Biobox? Our suite of high-resolution cameras both inside and outside the Biobox — and sensors capable of measuring pressure, temperature, humidity, and O2 levels — make certain that neither we nor the public will miss much of the life in the Biobox.

Do Not Tap on Glass

We are certain that, given the opportunity, Mrs. Slatoff’s fifth grade class at Pennsylvania’s Greencastle-Antrim Elementary School would jump at the chance to fly onboard Genesis II and do just that.

Mr. Bigelow’s donation to the school inspired a “Name the Scorpion” contest. The winning class gave the name “Antares,” heart of Scorpio, to one of our flight scorpions. We’ve chosen our male scorpion to be the honorary bearer of the name. He wears three green jewels on his back, and red markings on his claws.

Antares and his companions are now sealed up in the Biobox, waiting along with its mothership for transport to the launch site in Russia. Eventually, they will begin their off-world journey, traveling at 17,000 mph around the Earth at the altitude of 350 miles above the Earth’s surface. When that happens, the only way we’ll see them is via our onboard cameras through our Mission Control computers.

For now, the payload team pays daily visits to Antares and company in the Bigelow Aerospace Vehicle Assembly Clean Room, taking detailed status of each animal. “Biobox is unique in that it must blend precise mechanical devices and unpredictable live animals”, said Casey Harr, a robotic engineer on the Biobox team. Despite all the efforts, the insects may not survive the transport or the storage at the launch base, especially if there is a delay. Would they survive the shock of the launch? Would they ever get used to the slippery walls of the Biobox, or the conditions of microgravity?

We’ve come a long way since that meeting in Mr. Bigelow’s office. There is more work to go. God speed to our arthroponauts.

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