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Feb. 13 2000
Information for this issue has been taken from Space and Flight, Feb 4 & 12, 2000; NASA; and SpaceViews, Jan 31, 2000
In this issue:
* Earth Dodges Another Asteroid
'Threat'
* NASA May Build Space Station
Component
* Glenn Earns High Marks In Space
* STS-99 (details on the shuttle mapping
mission)
* Deep Space One on Road to Recovery
* First Post-Repair Hubble Images
Released
* NASA Tidbits: NEAR spacecraft Earth's
magnetic field disturbed Valentine from Mars!
Earth Dodges Another Asteroid 'Threat'
An asteroid initially thought to be on a possible collision course with Earth in 2022 will miss the planet by millions of miles, astronomers said Tuesday after reviewing new data. For the fifth time in two years, reports of Earth-threatening asteroids were proven wrong within days of being announced.
Some scientists fear the public may become desensitized to the warnings. "Someday, we're going to find something that will have a 1 in 1,000 or 1 in 100 chance of impacting Earth," said James Scotti, who discovered the asteroid last month at Kitt Peak National Observatory. "When that happens, I'd rather us be taken seriously." Scotti did not know about the celestial rock's possible trajectory until Monday, when Italian researcher Andrea Milani posted an Internet message warning of a 1 in 1 million chance of a collision and asking other astronomers to track it carefully. A day later, Milani announced that the new observations allowed him to make more precise calculations. The asteroid, named 2000 BF19, would come no closer than 3* million miles to Earth over the next 50 years, he said. "This change is the result of computation I did today from the response of my call to arms yesterday," Milani said. He said it took about four hours to compute the course using the new observations from around the world.
The object also was being followed at the Near Earth Object Program at the National Aeronautics and Space Administration's Jet Propulsion Laboratory, but it quickly became apparent that the half-mile-wide rock posed no real threat. The laboratory has never issued an asteroid collision warning. "In almost all of the five cases, we're the ones who came back and said it won't happen," said the program's manager, Donald Yeomans. "We're the nay-sayers."
NASA May Build Space Station Component
If the Russian space agency does not place an overdue major component of the international space station in orbit by this summer, the United States will send up a custom-fitted substitute to ensure that work on the station continues, NASA Administrator Daniel Goldin said Thursday. "We are at the moment of truth," Goldin told reporters. "It is up to the Russians to demonstrate to America and the other international partners their commitment to the international space station." Goldin's remarks followed Russia's surprise announcement late last month that it will revive the aging Mir space station that was abandoned by cosmonauts in August. That effort presumably would draw essential resources and personnel away from Russia's promised but delayed contribution to the new international station -- the service module containing the crew quarters -- which was to have been launched last summer. "We went through some very important soul-searching over the past few weeks," Goldin said. NASA concluded that if the operation of the Mir interferes with the Russian commitment, then the United States is prepared to put an interim control module in orbit as early as December. That unit is designed to give the station temporary propulsion and position control. The $200 million component would have to be custom-configured to fit into the existing station. But NASA has been under heavy pressure from Congress to devise contingency plans in the event of a Russian default, and Goldin said a schedule is already in place to make the change.
Glenn Earns High Marks In Space
When John Glenn went into space as a grandfather in the fall of 1998, many thought it was a well-deserved publicity stunt for NASA and the first American to orbit Earth. Glenn kept insisting it was a serious scientific mission -- to study the adaptability older people to space. And indeed, a good deal was learned from the mission. Doctors said they were surprised. At age 77 they found the senator-astronaut withstood the rigors of nine days in weightless space almost as well as his younger crewmates. He slept fitfully, but in almost every other category, he "came out about the same as the younger astronauts," said Glenn. In flight, Glenn was outfitted with sensitive monitors to track his every reaction. Now, 15 months later, the results of those scientific studies are being reported at the National Institutes of Health. They show, like most older people on the ground, he did lose sleep. A chart followed Glenn's vital signs for eight days. Black areas indicated when he was awake. Other areas indicated his intended sleep time, but it was interrupted a lot. Two hours of interruption here, an hour there, almost another hour, then two more hours and two more hours again. But his heart did as well as the others' in flight, and so did his muscles. During the stressful time of landing, while the younger astronauts' hearts raced at an average 115 beats a minute, Glenn's beat a slower, calmer 95. "We thought that when he was out in space, his responses would be a lot slower to adapting to space (and that) when he came back to Earth, his re-adaptation would be slower than his younger counterparts," said NASA physician and former astronaut Dave Williams. "What we observed, which is quite remarkable, is that his rate of recovery was virtually identical to the younger astronauts." Glenn got motion sickness briefly as he landed, but so do about one in 10 younger astronauts. His leg muscles were a little swollen for about a month after the flight as he re-adapted to the weight of gravity. But that's it. Overall, it's an excellent report card. I hope this is a forerunner that says that the elderly can do a lot more than most people think they can, they stay in reasonable shape and can live very productive lives to an older age than anticipated," said Williams. "You don't have to just sit on a couch at age 65." Would Glenn go to space again? Glenn admitted Friday that it's not going to happen. But he said that if he had the chance, he'd do it tomorrow.
STS-99 (details on the shuttle mapping mission)
The space shuttle Endeavour reaches orbit this week, is on a mission that promises to generate a wealth of scientific windfalls -- and that has already generated a bit of controversy and debate.
The goal of STS-99, known as the Shuttle Radar Topography Mission (SRTM), will be to map most of the Earth using a set of radars mounted in the shuttle's cargo bay and at the end of a 60-meter (197-foot) boom that will be deployed out the side of the cargo bay.
Using a process called radar interferometry, the data collected by the cargo bay radar will be combined with the data collected by the radar at the end of the mast, generating a three-dimensional map of the Earth.
Watching over the radar will be a team of four mission specialists: American astronauts Janet Kavandi and Janice Voss, German astronaut Gerhard Thiele, and Japanese astronaut Mamoru Mohri. The mission will be commanded by Kevin Kregel, with Dom Gorie as pilot.
The data will be stored on board the shuttle on tapes, with nearly 10 terabytes of data collected by the end of the mission -- enough to fill 15,000 compact discs. Data will be coming in four times faster than it can be sent down to the ground, so only small pieces of data will be sent back to verify the radar system is operating as planned.
The physical aspects of the mission are also challenging. The 60-meter radar boom extended out the side of the shuttle will be the longest rigid structure ever deployed in space. The radars will require 900 kilowatt-hours of electricity to operate, near the limits of the shuttle's capability.
If all the systems work as planned, though, the payoff will be the highest-resolution map of the Earth ever generated, with resolutions as sharp as 30 meters (99 feet) per pixel over landmasses between 60 degrees north and 56 degrees south, which account for 80 percent of the Earth's land surface.
This high-resolution map promises to have an impact on fields ranging from geology and ecology to archaeology, disaster relief, and urban planning. "We are at the beginning of a new age in remote sensing," said Ghassem Asrar, NASA associate administrator for earth science. "For the first time, we are trying to build a three-dimensional structure of the Earth from space."
The scientific, and related commercial benefits, of the SRTM data set have been emphasized by NASA and the German and Italian space agencies, which are partners with NASA on this mission. However, the role of another mission partner, the National Imagery and Mapping Agency (NIMA), has generated a degree of controversy.
The U.S. military is also highly interested in a high-resolution topographic map of the Earth, for applications ranging from flight simulators to improved terrain maps for cruise missiles.
NIMA, which provided the funding for the mission, will collect all the data, but will only release the 30-meter resolution data for the United States. For the rest of the world, a degraded map with a resolution of 90 meters (295 feet) per pixel will be available, still better than existing maps, but less than what scientists would like.
NIMA and NASA officials say that the higher-resolution data will be made available to scientists who request specific portions of it for their research, but who will be eligible for what data is unclear. "We want to cooperate," said NIMA director Lt. Gen. James King.
Another bone of contention for scientists is the length of mapping operations. Originally intended for 10 days, NASA officials announced earlier this month mapping would end a day early in the event the boom failed to retract properly, requiring a spacewalk to bring it in. Mission managers had previously planned to simply jettison the boom and its radars, which cost an estimated $140 million, if the boom failed to retract.
Scientists, though, are fighting to restore that extra day of mapping, or else possibly refly the radar mapping mission. "All options are available," said Asrar on Sunday. "We are examining all options and will make the necessary decisions as required."
Shuttle mangers, though, seem pessimistic the mission can either be extended or quickly reflown. At a Saturday briefing, shuttle program manager Ron Dittemore said it is unlikely the mission could be extended an additional day to allow for additional mapping, since the shuttle likely won't be able to conserve enough consumables during the mission to allow for the extra day. Reflying the mission in the near future is also unlikely, because of work on the SRTM payload that would have to be performed after the mission.
Deep Space One on Road to Recovery
NASA's Deep Space One (DS1) spacecraft, which has been in a safe mode since a star tracker failed in November, took a major step towards resuming normal operations earlier this month when it successfully pointed its high-gain antenna at Earth.
The innovative maneuver, completed January 14, not only allowed engineers to download a backlog of scientific and engineering data collected by the spacecraft, but raised hopes that the spacecraft can operate normally despite the failure of a key instrument.
First Post-Repair Hubble Images Released
A stunning nebula and a giant cosmic "magnifying glass" are the subjects of the first two images taken by the Hubble Space Telescope since its successful repair last month.
The images, taken January 10-13 by Hubble's Wide Field and Planetary Camera 2, were released early Monday, January 24, by NASA and the Space Telescope Science Institute to show the orbiting observatory was back in business. One image was of NGC 2392, known as the "Eskimo Nebula", and the other was of the galactic cluster Abell 2218.
"Thanks to the great work by the astronauts, Hubble is better than new," said Ed Weiler, NASA associate administrator for space science. "I think there is no better proof than these pictures that NASA's capability to send humans into space to work on Hubble has had a vital role in space science and the renaissance in astronomy we're now seeing."
Guess Who's Coming to Breakfast?: The NEAR spacecraft is now less than 1000 km from asteroid 433 Eros. It is scheduled to enter orbit around the space rock at 10:33 EST on Monday morning. Critical science observations are slated to begin 11 hours earlier when the spacecraft passes directly between the Sun and Eros. FULL STORY at http://www.spacescience.com/headlines/y2000/ast13feb_1.htm
SPACE WEATHER ALERT: The NOAA Space Environment Center reports that the Earth's magnetic field was disturbed today due to a coronal mass ejection that left the Sun on February 9. Geomagnetic activity, including high-latitude and mid-latitude aurora, could continue for the next 24 to 48 hours. See http://www.SpaceWeather.com for more information.
Valentine from Mars! NASA has received a topical topographical gift from another planet, Mars. As if saying Happy St. Valentine's Day from the Red Planet, the Mars Global Surveyor's Mars Orbiter Camera captured a unique view of a bright, heart-shaped mesa in the south polar region. To see the photo and other recent NASA newsbriefs and images, visit http://www.nasa.gov/today/index.html
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Submitted by
CMDR Constance Sanders
USS Yorktown
Chief, Space Activities Committee, SFC
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