First, the weather: Solar activity is at low-to-moderate levels, although one large sunspot group could generate some medium-sized flares. Two masses of plasma have erupted from the sun, but they're not headed our way. While geomagnetic-field activity is a little unsettled due to high-speed particles from a big coronal hole, the probability of a severe geomagnetic storm is just about zilch. And hey, here's some good news: none of the 452 known asteroids that could conceivably hit our planet are currently on a collision course.

No, that doesn't sound like the weather report you heard on the radio this morning, but it is the kind of information issued every day by the National Oceanic and Atmospheric Administration's Space Environment Center. The SEC monitors conditions in the environment between the sun and Earth, collecting and analyzing data received from a large number of ground-based observatories and orbiting satellites. A lot of that data is collected by instruments designed and built at the University of New Hampshire.

It might sound odd to talk about "the environment between the sun and Earth." It's just empty space out there, right? Not really. The apparent void beyond Earth's atmosphere is actually full of charged particles (plasma) continuously streaming from the sun in the solar wind. These particles, moving at about a million miles per hour, constantly buffet Earth's magnetic envelope, which provides an extremely effective shield.

When strong surges in the solar wind hit the magnetosphere, they generate an electric current that flows from pole to pole, which we see as the aurora. These disturbances, often called geo-magnetic storms, can cause serious problems on Earth. In 1989, for example, a geomagnetic storm induced power surges in electrical transmission lines in Quebec, tripping circuit breakers and plunging the entire province into darkness for nine hours. Storms in 1994 and 1997 knocked out three communications satellites, which had to be replaced at a cost of about $200 million each. Geomagnetic storms also block high-frequency radio transmissions for days at a time and interfere with high-tech navigation systems on planes and ships.

Fortunately, major geomagnetic storms are relatively rare events. NOAA estimates that some 2,600 storms occur in an average 11-year solar cycle, but we don't even notice most of them. Only a few--about four in each solar cycle--are serious enough to be labeled "extreme," the highest ranking on NOAA's five-level scale.

Scientists have become much better at forecasting those extreme events in recent years. A number of research satellites launched since 1994 (including six carrying instruments designed at UNH) have given forecasters better tools to monitor solar activity. They have provided a wealth of new information about the sun, and they serve as a kind of early-warning system when major solar disturbances occur.

A UNH space science team is currently working on an instrument for NASA's next major solar mission. Known by the acronym PLASTIC (Plasma and Suprathermal Ion Composition), this instrument is designed to analyze the protons, alpha particles and heavy ions carried in the solar wind. It is part of a package of four sensors that make up NASA's Solar-Terrestrial Relations Observatory (STEREO), scheduled for launch in 2005. STEREO's other instruments will be provided by the University of California at Berkeley, The Naval Research Laboratory in Washington, D.C., and the Centre National de la Recherche Space Scientifique Observatory in Paris, France.

Actually, the UNH team is working on two PLASTIC instruments, because the STEREO mission involves two satellites equipped with identical sets of sensors. They will orbit the sun at the same distance as Earth, with one positioned well ahead of Earth and the other well behind. This will give scientists their first three-dimensional view of the sun and their first good look at the complex contortions of gas and magnetic fields associated with coronal mass ejections (CMEs), enormous eruptions that can hurl 10 billion tons of plasma into space at speeds exceeding 2 million miles per hour.

"We are especially interested in looking at solar wind explosively released from the sun as CMEs," explains Antoinette (Toni) Galvin, an associate research professor in the physics department and the Institute for the Study of Earth, Oceans and Space. "These eruptions are known to be a primary cause of space weather on Earth. We'll also be looking at other particles in space, including material that comes from outside the solar system." Galvin is the principal investigator for the PLASTIC project. It's her job to administer the $7 million budget and coordinate the activities of everyone working on the instrument. That's no small task, since pieces of PLASTIC are being built not only at UNH, but also at the University of Bern in Switzerland and the Max Plank Institute for Extraterrestrial Physics and the University of Kiel, both in Germany. NASA's Goddard Space Flight Center in Greenbelt, Maryland, is also a partner in the project, helping to test and calibrate the components.

The completed PLASTIC instruments will look something like large, ungainly cameras perched on top of the STEREO satellites. Each instrument will be about the size of a portable television set, weighing about 30 pounds, and will draw only 10 watts of power, provided by the satellite's solar panels. Fitting all of the project's science requirements into a package that small is quite a challenge, Galvin points out. Sitting at the desk in her small office on the fourth floor of Morse Hall, she opens a book of schematic drawings of various pieces of the instrument. "Each of these components is custom-made," she says. "You can't pull them off the shelf. They have to be designed for the specific experiment and for the space environment, so almost by necessity, they tend to be one of a kind."

Right now, the PLASTIC team at UNH--a total of about 20 scientists, engineers, technicians and students--is designing, building and testing those components. "The scientists know what they want to measure and can conceptualize a way to do it, but the engineers really make it work. A lot of the inventing comes from the engineers," Galvin explains.

Some of that inventing is being done by students. Four undergraduates are currently working on the project, experimenting with alternative solutions to particular engineering problems, looking at the performance of PLASTIC components in computer simulations, or testing engineering models in a vacuum chamber in the space science lab. "These students are actively involved with important design elements. This is not a paper project for them," Galvin emphasizes. "What they help us to design will fly in space."

Alex Crawshaw, a junior mechanical engineering major from Gilford, New Hampshire, has been part of the PLASTIC team since his freshman year. His workspace is tucked into one corner of a large room shared by about a dozen students assigned to various space science projects. Using a specialized computer-assisted-design program, he's constructed a computer model of a piece of PLASTIC called the time-of-flight chamber. "Basically, all it does is measure the speed and energy of particles that have been collected from the solar wind," he explains.

The time-of-flight chamber includes particle detectors that use carbon foils only a few atoms thick. They are so delicate that even a breath of air moving through the chamber would destroy them, yet the PLASTIC engineers had to design detectors rugged enough to withstand the stresses of launch and the space environment. When prototypes of the detectors were sent to the Goddard Space Flight Center for testing in a NASA lab, Crawshaw went along. "I spent a whole week there, working with NASA engineers," he says. "That was big. That was fun."

Crawshaw, who dreams of an assignment aboard the international space station someday, still finds it amazing that he's able to work on a NASA project as an undergraduate. "It's pretty cool to think that in 2005, this piece I'm working on will be orbiting above my head somewhere," he observes.

He's also excited to be working directly with a scientist of Galvin's stature. "I usually see her a couple of times a day. When I come up with a problem, the first thing I do is go to her with all of my documentation. We might spend a couple of hours in her office, going over ideas to work it out. She has extensive knowledge of ... well, just about everything, it seems to me."

That breadth of knowledge is a prerequisite for the principal investigator in a major space experiment. "You need someone who has seen a lot of previous research, remembers it, and knows how to apply it to the current project at the right time," says UNH physicist Mark Popecki, a coinvestigator for the STEREO project. "Toni knows the science and has had enough experience with the hardware to make good decisions about which engineering approaches will work best. And when something isn't working, she has good intuitions about what might be going wrong."

STEREO is the third of five solar-terrestrial probes planned by NASA to improve our ability to predict weather in space. One of its principal objectives is to collect data that will help forecasters to predict the effects of CMEs more accurately. CMEs are the most violent eruptions that occur on the sun and the cause of most major geomagnetic storms. Unfortunately, the CMEs that affect Earth most are the ones that are least likely to be detected by telescopes on the ground or by satellites in orbit around the planet, simply because it's hard to see something that's coming right at you. That's why each STEREO satellite will orbit the sun in a position far enough from Earth to provide a different perspective.

Right now, forecasters rely primarily on SOHO for early warning about CMEs. UNH scientists worked on one of the key instruments on SOHO, which was launched by the European Space Administration in 1995. The satellite monitors the sun and beams a continuous stream of images to researchers on Earth. Those chronographs can show a CME in progress two- to four-days before the blast of plasma gets here.

"But even when we know a CME is coming, we still don't know whether it will be geo-effective," Galvin says. "Will it actually cause a magnetic storm when it reaches Earth? And if it does, how big a storm will it be? Sometimes an event that comes off the sun seems minor--not dramatic at all, visually--but when it reaches Earth, it has a big effect."

Both SOHO and another satellite equipped with a UNH-built instrument, the Advanced Composition Explorer (ACE), can actually sample and analyze the solar wind to collect more detailed information about what's coming our way. But by the time they're able to do that, whatever is coming is almost here. "Basically, by the time we know whether it's going to affect us or not, we have only about a one-hour warning," Galvin observes. "What we're trying to do with STEREO is to get a better correlation between the in situ measurements of the solar wind and the remote observations of the sun, so we'll have a better idea of which solar events will have an effect on Earth."

Galvin's goal is not just to become a better space-weather forecaster, but to gain a deeper understanding of how the sun works. "We know there's an 11-year sunspot cycle. We know this has something to do with the fact that the sun spins faster at the equator than it does at the poles. This twists up magnetic field lines, and we know that sunspots and coronal mass ejections and flares are ways of releasing this pent-up magnetic energy. But we don't understand why the cycle is 11 years. We don't know how to predict whether this cycle will be more intense than the last, or when the next big event is going to happen. We don't understand these things, so we need more in-depth information about how and why the sun does what it does."

Galvin glances at the computer monitor on her desk, which displays a real-time image of the sun as seen by SOHO. "When I think about the sun, I don't envision the big yellow ball that we see out the window," she says. "I always think of these extreme ultraviolet images. Looking at them, you can see that even when the sun is quiet, it's percolating, churning. It's keeping busy, and it's just fascinating to look at."