From the Drawing Board to the Stars
This month, after years of working, dreaming, and exploring, a group of excited scientists and engineers got to see their plans for revolution realized when dramatic pictures from the spaceborne Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) came streaming back to Earth. The IMAGE satellite is a unique eye-in-the-sky for studying space storms that take place in and around the Earth's magnetosphere, the region of space controlled by our planet's magnetic field.
Right: Dr. Jim Burch, principal investigator for NASA's IMAGE space weather satellite.
"IMAGE is the first all new thing to come along in a while," said Burch. "Before now, you couldn't see [the magnetosphere] or how it changed. All that was visible was the aurora. We couldn't see anything outside. Then in the late 1980's people began discovering that we could create instruments to image the magnetosphere -- we could actually take 3D pictures of this formerly-invisible region of space. So we needed a way to get these instruments up and working."Left: This of our planet's magnetosphere begins showing the Earth, which recedes as the shape and size of the magnetosphere comes into view. The solar wind deforms the magnetosphere into its characteristic shape. Where the magnetosphere and the solar wind meet is the "bow shock," represented in the animation by a faint, translucent bullet shape. Credit: Digital Radiance
The process of actually getting a satellite up is a grueling and complex one. Burch, as principal investigator, was integral in this process, and remembers the development of the project well.
"In 1991 teams began to form to propose [to NASA] a line of missions called solar terrestrial probes," said Burch. "Congress was in the middle of their approval process, and eventually approved a program for smaller explorers, beginning with NASA's MIDEX (Medium-class Explorer) program."
These teams began competing to be one of the first two science missions in the MIDEX program. There were two teams working specifically on proposals for a magnetosphere imaging satellite.
Over 45 proposals were submitted for consideration for the
MIDEX program. Two were selected by NASA's Office of Space Science:
IMAGE and the cosmic
Microwave Anisotropy Probe
Next for Burch came the decision about who would build the IMAGE craft.
"We teamed with Goddard for the proposal and we originally chose Goddard to build the spacecraft [while] we would provide the instruments," Burch said. "The problem was that the MAP people wanted Goddard, too. It was thought that one of the satellites needed to be built by industry. So, IMAGE went to Lockheed."
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Once that decision was made, Burch began the work on instrument development and team selection.
"We had a large team," Burch said. "There were 24 co-investigators and 26 participating scientists. These were not all the same as were on the B-Team when we were selected. After we found out we would actually be building IMAGE, I asked some people from the A-Team to join us. I wanted the best payload possible."
One co-investigator was in charge of each instrument that would be on board. There were a total of six instruments, each being built by the institution of the co-investigator, said Burch.
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Image Instruments & Institutions
The high energy neutral atom (HENA) imager images neutral atoms at energies from 10 keV to 500 keV. (Johns Hopkins University Applied Physics Laboratory)
The medium energy neutral atom (MENA) imager takes images of neutral atoms at energies from 1 keV to 30 keV. (Southwest Research Institute)
The low energy neutral atom (LENA) imager images neutral atoms at energies from 10 eV to 500 eV. (NASA Goddard Space Flight Center)
The extreme ultraviolet (EUV) imager takes ultraviolet images of 30.4 nm emissions from helium ions. (University of Arizona)
The far ultraviolet (FUV) imager images the aurora produced by the electron bombardment of oxygen (135.6 NM) and nitrogen (140-190 NM) and by energetic protons (121.8 NM). The instrument also images the exosphere (121.6 NM). (University of California at Berkeley)
The radio plasma imager (RPI) performs radio sounding of plasmas with densities from 0.1 cm-3 to 105 cm-3. (University of Massachusetts at Lowell)
The central instrument data processor (CIDP) performs payload command and data handling. It is the interface between the payload and the spacecraft. (Southwest Research Institute)
Now came the crunch time: time to actually finalize the plans for building the instruments and the spacecraft that would carry them into orbit.
"We needed to do things faster to keep costs down," said Burch. "So what we decided to do was to have SwRI developing the payload at the same time that Lockheed was building the spacecraft. In addition, SwRI was going to build the computers for the payload and the satellite to talk to each other, that way all the glitches could be worked out at SwRI."
Left: The IMAGE payload inside the nose of a Delta II rocket. Photo credit: Southwest Research Institute.
"It all worked perfectly so the tests began on the observatory," said Burch. "For example, we ran tests that simulated separation, ones that tested electromagnetic interference, and vibration tests. In August, IMAGE went into storage as a fully qualified spacecraft. It had been three years and four months from start to storage."
Burch also had reason to be pleased with his team and satellite as they came in well under budget. All that was needed now was a launch date.
"Getting a launch date was harder," Burch said. "We were flying on a Delta II and had a choice on a December or February launch date because of the Delta launch pad schedules. We had originally chosen February, because when the launch was being planned, we weren't done."
But as with all missions, there were other factors that would impact the launch. Delays mounted as several NASA missions failed and reviews were ordered on IMAGE.
"First an 'external review' was required, after the WIRE mission had their problem with the opened valve. We passed with rave reviews," said Burch. "Then the Mars Climate Orbiter mission failed, so a 'red team review' was required. Again rave reviews. Then the Mars Polar Lander failed and yet another review was required. Finally we were set to go."
At 6 p.m. on March 24, the night before
the launch was scheduled, permission was granted to launch, and
IMAGE lifted off from the Western Range at Vandenberg AFB, Ca.
on March 25 at 12:34 p.m. PST.
Right: IMAGE's Delta rocket awaits launch, then blasts off on March 25, 2000. Photo Credits: Dr. Dennis Gallagher, MSFC.
"I was in the control room when it lifted off," Burch said. "I was still worried about a few things, even though we had done so well in the tests. I was worried about the structure surviving the launch environment. And I was worried about the computer."
The computers on board the satellite were a single-string system. With no redundancy, a single failure could endanger the whole mission.
"If one computer dies, we were done for," said Burch. "There is a wire that extends from the third stage on the Delta II launcher to the satellite. When they separate, the wire breaks and turns the computer on. I was worried it wasn't going to turn on."
So Burch waited in the control room to see what would happen.
"I watched it for one hour until separation," Burch
said. "Then I waited for one more hour to turn the payload
computer on, which was done remotely from Goddard. At first nothing
happened, and I thought we were done. After about 15 minutes
past the time the computer should have switched on, we called
Goddard and discovered that they just hadn't sent the command
yet. Once they did, the computer came on and everything was fine."
IMAGE will collect data about the magnetosphere for the next two years, and possibly a year or two after that. Eventually radiation will kill some of the circuitry, said Burch. However, the next few years will provide more information about the magnetosphere than ever before, fulfilling the dreams of learning more about space for Burch and his team.
"Having it up there and working is more gratifying than
I can express," said Burch.
Above: Finally! After years of work and effort, NASA's IMAGE spacecraft is in orbit and returning pictures like these of electrified gas surrounding our planet. [more information]
Southwest Research Institute manages the IMAGE project
and leads the IMAGE science investigation. The IMAGE Principal
Investigator is James L. Burch.
The NASA/Goddard Space Flight Center purchased launch services for IMAGE, provided one of the instruments and also performs IMAGE ground data system and flight operations.
IMAGE First Light Movies and Pictures - from NASA/GSFC
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