Future Sprout

CNN.com; Sept. 20, 2001; Space: "Space Crops May Solve Earth Problems"

MSNBC.com; Sept. 26, 2001; Technology - Space News: "Shedding New Light on Space Farming"

Growing plants in space, to feed long-duration voyagers and out-worldly colonists, has been a staple prediction for space futurists. This idea took root with the reasoning that a regenerative food crop would take up less space than the equivalent rations of food carried onboard a ship or supplied regularly to inhabitants of permanent space or planetary colonies. There was also the added benefit of carbon dioxide removal and oxygen production from the plants. In fiction, the space-wrecked Robinson family, on television's "Lost in Space" series, was quick to pull out the hydroponics garden on every planet they crashed on. The more recent "Mission to Mars" motion picture featured a stranded Mars explorer living on the food and oxygen produced by a greenhouse on the Martian surface. So why wasn't the International Space Station (ISS) immediately setup with a "veggy" module from the start? Well it turns out that "astroculture" is not as simple as the futurists or fiction writers think.

Since the mid-70s, Russian orbital missions have tried to grow plants in space. Typical problems encountered include the lack of gravity inhibiting the ability of plants to put down roots. The atmosphere on board and the lighting conditions were found to affect plant growth and the lack of insects prevented natural pollination. In the early 1990s, a 1-square-meter by 40-centimeter high greenhouse was put aboard the famous Mir station for experiments in serious food production. Early-on, cosmonauts were able to grow lettuce and radish. By 1995, the U.S. became involved with the Russians in trying to get wheat to grow in the greenhouse. This resulted in two wheat harvests in 1999 -- the second harvest as a result of 508 seeds from the first harvest. Unfortunately, these successes came at the close of Mir's life as an experimental station, and the greenhouse burnt up over the Pacific with the Mir complex.

On Earth, advancements have been made in developing the proper artificial lighting for astroculture. Typical lighting systems used on Earth generate heat, and count on the availability of replacement parts and cheap power. In space, habitat power may need to be rationed, replacement parts cannot be had quickly, and excess heat is not easily dumped into the vacuum of space.

One promising method is to use energy efficient and long-lasting light-emitting diodes (LEDs) for the next generation space greenhouse. Light the monochromatic LEDs used on some high-tech traffic lights, the diodes produce little heat and can be chosen to deliver light in the color spectra absorbed by plants for grow. Not producing light of unnecessary wavelength also saves on power. Scientists have used blue and red LEDs to grow lettuces and radishes. An LED greenhouse module is being designed for the ISS. It may reach the station within three years and produce fresh vegetables to supplement the station crew's diet.

Another promising light source are sulfur microwave lamps; they are the most efficient electric lighting source known and can reproduce the brilliance of the Sun. Developed within the last decade, they consist of quartz spheres containing sulfur and argon gasses. Microwaves are used to excite the gasses that give off light. With no filament to burn out, the lamps should last for many years.

Astroculture can also be used to give a new boost to Earth-based agriculture. This year NASA commenced a program to allow industry to conduct long-term plant research on the ISS. One of the project's aims is creating crops that would better prosper on Earth. It turns out that genetic manipulation using bacteria to transfer genes works better in the weightless environment of space.

We're Another Centimeter Closer to Pluto!

Southwest Research Institute; Sept. 28, 2001; Press Release: "Scientists and Engineers Complete NASA-Funded Phase A Study Of Pluto-Kuiper Belt Mission"

The "New Horizons" team has just completed a "Phase A" design study for a Pluto-Kuiper Belt mission to the outer reaches of the Solar System. The team consists of members from the Southwest Research Institute (SwRI) and Johns Hopkins University (JHU). NASA funded the $450,000 study to design a complete mission, with spacecraft, instruments, trajectory, and a public outreach plan. As expected, the trajectory includes a gravity boost maneuver at Jupiter to cut down on the amount of propellant to reach Pluto after a decade of travel. The launch could be made in 2004 or 2006, with arrival between 2014 and 2018.

The proposal saves money, time, and reduces risk by reusing systems already proven on previous JHU spacecraft. The spacecraft include a variety of instruments to map the surface of Pluto and its moon Charon, as well as study the composition of Pluto's tenuous atmosphere and how fast it is being lost into space. These instruments include miniature cameras, UV and infrared spectrometers, radio science instruments, and instruments to study space plasma.

New Horizons is one of two teams vying for the chance to send a space probe to the most distant planet and largest member of the Kuiper Belt. The rocky bodies out there are covered with ices and simple molecules left over from the formation of the Solar System. Never having been exposed to the high temperatures of the inner system, scientists are eager to examine their pristine composition. But, due to budgetary constraints, it is still not clear if the winning design proposal will be funded for an actual mission.

Dwarf May Have Left a Streak

University of Illinois at Urbana-Champaign; Sept. 28, 2001; Press Release: "Strange Trail Suggests Presence of Galactic Interloper"

Stretching 2.5-degrees across the sky, near the Big Dipper, is a Y-shaped filament of ionized gas. It was discovered by researchers at the University of Illinois at Urbana-Champaign and the University of Wisconsin at Madison; on images made in the hydrogen-alpha spectrum. Astronomers are now trying to track down the source of this trail. "We believe the gas trail was produced by the radiation from a white dwarf or some other low-luminosity source zipping through the local interstellar medium and leaving behind an ionized wake," says Peter R. McCullough of the University of Illinois.

"We believe the gas trail was produced by the radiation from a white dwarf or some other low-luminosity source zipping through the local interstellar medium and leaving behind an ionized wake."
 -- Peter R. McCullough, University of Illinois

Perhaps 300 light-years distant, the outer space "contrail" is 20 arc-seconds wide, with the base segment 1.2-degrees long. The remainder consists of diagonal segments separated by 5-arcminutes. According to McCullough: "The filament's large angular size also suggests it is nearby, and therefore we should be able to identify what created it."

Ionization trails left by white dwarfs had been predicted by Harvard astronomers in the early 1980s. This may be the first example of one to be discovered. Astronomers may attempt to locate other trails by examining the distance and direction of motion of known white dwarfs.

Night of the Meteors

Space.com; Sept. 24, 2001; Solar System: "Satellites Face Worst Threat Since 1966 With November Meteors"

This November 18th the yearly Leonid meteor shower will reach its peak. In the last few years the shower has become quite active and astronomers have become much better at forecasting the shower's peak time and meteor rates. Meteor counts of from 1,400 to 15,000 are predicted this year.

The meteors consist of dust grains ejected by periodic comet Tempel-Tuttle,; that comet takes 33-years to orbit the Sun. Because the comet orbits in the direction opposite the Earth, these grains strike our planet more swiftly than any other major meteor shower. Leonid observers often see bright streaks, many leaving a persistent train of debris in the sky.

What is grand and majestic for the ground observer is not always beautiful to satellite owners and operators. Moving at hundreds of thousands kilometers per hour, even a small meteor grain can damage fragile satellites and throw them off course. Fast moving meteoroids can strike and vaporize parts of satellites into plasma. The conductive plasma can allow electric current, produced or stored by the satellite, to arc, destroying instruments. In such a way was a communications satellite disabled when hit by an August Perseid meteor in 1993.

The last major, potential, satellite-damaging meteor event was 1999, when satellite operators world-wide reoriented their hardware to present less of an opportunity for meteoroid strikes. Because of the vastness of space around the Earth nothing happened then, but this year the risk is five to 10 times greater: ten meteors per square kilometer of sky at every instant is possible at peak. Still, the odds of any one satellite being damaged ranges from 1-in-1000 to 10,000. So perhaps only one of the multitudes of operational satellites will be affected in the days before and after the November 18 peak.