Mars ... Flood Reig O'ver Me
The Dust Bowl
Viking's Silver Anniversary
POSSE to Ride to the Rescue?
Mars... Flood Reign O'ver Me
The Red Planet Mars, on the surface a desiccated desert, is showing increasing signs of a water-laden past and perhaps present. A flood of new evidence pooled from dramatic images from the Mars Global Surveyor (MGS) spacecraft have whetted the appetites of scientists divining the Red Planets past. New high-resolution imagery from MGS shows evidence of ground ice on Mars as recently as 10 million years ago. More striking is that the signs of geologically recent ice deposits are near Mars equator, where the frosty deposits were probably no deeper than 5 meters below the surface. If ground ice was present within 5 meters of the surface only a few million years ago, it is very likely to persist today within about the upper 10 meters, said University of Arizona planetary sciences professor Alfred McEwen. This is especially interesting because it is an equatorial region of Mars, more accessible to exploration.
Equally exciting, piles of crater-topped debris caused by the teakettle-like explosion of water through volcanic lava flows point to recent liquid water in Mars past. According to a model devised by researchers, so-called rootless cones formed after volcanic eruptions melted frozen water near the surface of Mars 10 million years ago practically yesterday in geological terms. The melting caused floods that carved channels and seeped into the ground. We think lava flows have advanced over the wet ground causing steam explosions that built these rootless cones, said Laszlo Keszthelyi, a senior researcher at Arizonas Lunar and Planetary Laboratory. It means Mars is not dead geologically. Volcanic eruptions and water floods are something ongoing into the current geologic era.
Few doubt that rivers run through Mars past; the largest flood channels in the solar system reside on the Red Planet, in fact. A system of gigantic ancient valleys (some as much as 200 kilometers wide) lies partly buried under a veneer of volcanic lava flows, ash fall and wind-blown dust in Mars western hemisphere. New observations made with MGS laser altimeter reveal slope valleys northwest of the huge Martian volcano, Arsia Mons, and south of Amazonis Planitia, site of a postulated ocean. The best explanation is that the slope valleys were formed by catastrophic floods 50,000-times larger than the Amazon River, said James Dohm of the University of Arizona. At their peak, the floods would have filled a large ocean hypothesized for northern Mars dubbed Oceanus Borealis in about 8 weeks. The Tharsis region has had pulses of major magmatic activity that triggered catastrophic floods that sculpted the surface, ponded, perhaps forming oceans and lakes that in turn perturbed the climate, Dohm said.
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The Dust Bowl
The largest dust storm seen on Mars since NASAs Mars Global Surveyor (MGS) spacecraft arrived in 1997 is currently raging across half the planet. This is by far the largest storm weve seen during the Mars Global Surveyor mission, said Philip Christensen, principal investigator for MGS thermal emission spectrometer. We expect that the storm will continue to grow, perhaps becoming a global storm of the type that was seen during the Mariner 9 and Viking missions in the 1970s, Christensen added.
Scientists first noticed the incipient storm in mid June when a dust cloud appeared in the Hellas Basin in the southern hemisphere. A week and a half later, the storm began to intensify and expand. Since then, the dust storm has grown to beyond Grapes of Wrath proportions, expanding well into the northern hemisphere and wrapping more than halfway around the planet. This storm began as a small dust cloud inside the Hellas Basin, a nine-kilometer-deep impact crater in Marss southern hemisphere, says Christensen. At first the cloud did little, alternately growing and retreating as days passed, but never expanding until June 27th. Thats when the storm exploded, added Christensen. It crossed some critical threshold and really began to grow. By early July the dust cloud had spilled out of the Basin and enveloped much of the planet.
No one knows exactly how Martian dust storms grow to such proportions, says Christensen. One theory holds that airborne dust particles absorb sunlight and warm the Martian atmosphere in their vicinity, he explained. Warm pockets of air rush toward colder regions and generate winds. Strong winds lift more dust off the ground, which further heats the atmosphere. Whatever the cause, this isnt the first time that visitors to Mars have been greeted by billows of talcum-fine powder. Mariner 9 arrived at Mars in 1971 (the first spacecraft to orbit the Red Planet) only to find the surface of the entire globe obscured by a worldwide haze of dust. Only Olympus Mons, a giant volcano 24 kilometers high, peeked above the clouds.
NASA scientists will monitor the current dust storm over the next few months to see how this powdery tempest develops and test their predictions of more storms to come. Atmospheric scientists have been waiting for a beautiful storm like this, says Christensen. The data were collecting are marvelous, and I suspect there will be a rush of papers in the months ahead answering some of the questions we have about these events. Fortunately, the storm should not have a major impact on the planned arrival of another spacecraft, the 2001 Mars Odyssey, in October. Well use the instruments on Global Surveyor to monitor the atmosphere on an hourly basis, providing the Odyssey spacecraft team the information they need to keep Odyssey at the proper height where it can safely fly through the atmosphere, Christensen said.
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On July 20th, the U.S. space agency, NASA, and other space enthusiasts celebrated the silver anniversary of Vikings soft-landing on the surface of Chryse Planitia, becoming the first successful mission to land on the Red Planet, as well as the first successful American landing on another planet. The treasure trove of images and data from the twin Viking landers and orbiters remains a valuable scientific resource for the study of Mars.
The Viking 1 lander operated on the surface until November 1982, and together with its twin, Viking 2, took 4,500 unprecedented images of the surrounding surface and more than three million weather-related measurements, while the two orbiters took 52,000 images representing 97% of the Martian globe. Viking also poked and prodded the Red Planet, looking under rocks and sifting grains of regolith into a suite of biology instruments in the search for life. For most scientists, the $1 billion probes provided a definitive No! to the question: Is there life on Mars? But to others, the negative reply was less persuasive.
Picking up where Viking left off, scientific teams are now readying experiments to repeat the question. The European Space Agencys (ESA) Mars Express, targeted for a June 2003 liftoff, will be a major part of the truth squad. Once in Mars orbit, the ESA spacecraft will cast off the British-built Beagle 2 lander, which will carry on where Viking left off, said Colin Pillinger, lead scientist for the lander and professor at The Open Universitys Planetary and Space Sciences Research Institute in Britain. Beagle 2 will go back to Mars with an analytical method, which detects every atom of carbon in all its forms. This time we should be able to find a body if it exists...even if organic matter has been degraded by processing in the hostile environment of Mars, Pillinger said.
Outfitted with the most sophisticated analysis system built to date, Beagle 2 far exceeds what Viking was doing, said Everett Gibson, an adjunct scientist on the lander. Among its abilities, Beagle 2 can sniff out the presence of methane, which could point to Martian organisms exhalations, a product of metabolism. Finding a methane signature would also shore up the notion that Mars may harbor a subsurface biota, Gibson said.
Joining Beagle 2 on Mars, but at separate landing sites, will be twin geology-laboratory rovers built by NASA, each the size of a desk and capable of traveling up to 100 meters a day. Capable of exploring like a field geologist, the Mars Exploration Rovers are concentrating not on current life forms, but the Mars of long ago. Its a different, complementary approach, said Steven Squyres, principal investigator for the Athena science payload to be hauled by each of the rovers
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POSSE to Ride
to the Rescue?
Faced with tight budgets and mounting cost overruns, NASA managers have repeatedly tried to shoot down future missions to Pluto and beyond, but Congressional proponents of such a mission have at least postponed High Noon for a proposed Pluto probe. In response to Congressional pressure, NASA has selected two proposals for detailed mission feasibility studies as candidates for a Pluto-Kuiper Belt (PKB) mission to explore the only planet in our Solar System yet to be visited by a spacecraft from Earth.
The two proposals judged to have the best science value were among five proposals submitted to NASA in April 2001. The first proposal to ride to the rescue was the Pluto and Outer Solar System Explorer (POSSE) led by NASAs Jet Propulsion Laboratory (JPL) and Lockheed Martin Astronautics. Also chosen for further study was a bid by Johns Hopkins University Applied Physics Laboratory called New Horizons: Shedding Light on Frontier Worlds. If funding is provided in the FY 2002 budget and either proposal is ultimately selected, NASA could fly a spacecraft to Pluto and beyond in the 2004-2006 time frame with arrival at Pluto before 2020.
Both proposals are for complete missions, including launch vehicle, spacecraft and science instrument payload that includes imaging instruments, a radio science investigation, and other experiments to characterize the global geology and morphology of Pluto and Charon, map their surface composition, and characterize Plutos atmosphere. The PKB mission represents a possible opportunity to visit the only planet not yet explored by spacecraft, said Colleen Hartman, Pluto Program Director in NASAs Office of Space Science. Its really an opportunity to, in a sense, look into a deep-freeze of history which could tell us how our Solar System evolved to what it is today, including the precursor ingredients of life.
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6 MayThe first space tourist returned to Earth from his trip to the International Space Station (ISS). Tito and two Russian cosmonauts blasted off from Kazakhstan on 28 April and spent two days in orbit before docking with the ISS. Titos presence distressed NASA, who complained that the station was no place for an amateur, even though Tito underwent extensive training as part of the $20 million trip.
8 MayA Zenit 3SL rocket carried the second of two digital radio broadcasting satellites into orbit for XM Satellite Radio from the Odyssey Launch Platform in the Pacific Ocean. Customers will be able to choose from almost every category of music in addition to content from the companys partners, which include: Sesame Street Workshop, NASCAR, CNBC, USA TODAY, One-On-One Sports, Hispanic Broadcast Corporation, C-SPAN Radio, Clear Channel and DIRECTV.
15 MayA Proton rocket launched the PAS-10 satellite into orbit from the Baikonur Cosmodrome. The communications satellite will replace an older satellite that was serving the Indian Ocean region and reaching customers in Asia, Africa and Europe
18 May The National Reconnaissance Offices GeoLITE spacecraft launched into orbit aboard a Delta II rocket from Cape Canaveral. The satellite carries an experimental laser communications payload and an operational UHF data relay payload.
20 MayThe Progress spacecraft 255 launched from Baikonur aboard the Soyuz-FG rocket, a modified Soyuz-U with 5 percent improved performance. The vehicle carries food and equipment, including spare computer equipment for the ISS.
24 MaySoggy tiles delayed the launch of the space shuttle Atlantis. Scheduled to launch on 14 June the Shuttle will launch no earlier than 20 June.
29 MayThe Cosmos-2377 launched from Plesetsk aboard a Soyuz rocket. The reconnaissance satellite carries a large recoverable capsule containing the camera system and film, as well as two small film capsules to be returned during the mission. The satellite will remain in space for 120 days.
2 JuneThe unmanned X-43A experimental aircraft aboard a Pegasus XL was destroyed shortly after deployment by a NASA B-52 launch aircraft from Edwards Air Force Base. After separation from the Pegasus, the X-43A, powered by a supersonic-combustion ramjet engine, failed to speed on its own. Two more X-43A flights are scheduled to provide NASA the research results it seeks in hypersonic flight. The NASA test was the first of three planned hypersonic free flights in the six-year, $185 million Hyper-X series of research aircraft.
4 JuneThe planned launch of an $85 million solar science mission was delayed at least five days while NASA investigated a Pegasus rocket failure that destroyed an experimental hypersonic aircraft. Set for launch aboard a Pegasus XL rocket, NASAs High Energy Solar Spectroscopic Imager or HESSI spacecraft will remain grounded until at least 12 June. Investigators want to make sure that the error will not recur on the Pegasus rocket that is slated to carry the HESSI spacecraft into orbit.
7 JuneCountdown was stopped several minutes before lift-off of an Ariane-4 rocket at the European Space Agency launch center in Kourou, French Guinea. Bad weather delayed launch of a telecommunications satellite for a Washington-based satellite operator INTELSAT for a few days.
NASA delayed launch of the next space shuttle flight due to problems with the new $1 billion robot arm. Atlantis will lift off no earlier than 7 July with a mission to deliver an airlock, or pressure chamber for spacewalks. The robot arm, which was attached in April, is needed to install the $164 million airlock. Although the main operating system of robot arm works fine, the backup system has a problem that could cause the arm to freeze up. NASA wants both the main and backup systems available.
8 JuneA Parus class navigation satellite, Cosmos-2378, launched into orbit from Plesetsk. This launch was the first Cosmos-3M flight since a failure in November 2000.
9 JuneAn Ariane rocket launched an Intelsat 901 satellite from Kourou, French Guinea. The first of the Intelsat 9 series, the satellite will provide telecommunications services in the Atlantic Ocean Region.
16 JuneAn Astra 2C communications satellite successfully launched into orbit for Societe Europeenne des Satellites (SES) from the Baikonur Cosmodrome. Built by Boeing Satellite Systems (BSS), Astra 2C is part of the SES constellation to provide direct-to-home television, Internet access and other communications services to more than 87 million homes in 29 nations. Astra 2C is designed to operate for 15 years.
19 JuneInternational Launch Services launched the ICO-2 satellite aboard an Atlas 2A from Cape Canaveral. The payload will provide mobile communications and data/internet services at S-band, supporting 4500 simultaneous calls.
30 JuneNASAs Microwave Anisotropy Probe (MAP) launched aboard a Delta 7425-10 launch vehicle from Cape Canaveral. Built in collaboration with Princeton University, the microwave instrument will observe the dark extragalactic sky with differential microwave radiometers and measure fluctuations in the cosmic 3 Kelvin microwave background.
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Medication Use in the US Manned
By Eleanor A. ORangers, Pharm.D.
Despite the fact that the US astronaut
corp is relatively healthy, medical events that could impact crew operations
on space missions are surprisingly common. For example, during the first 33
shuttle missions, 83% of crew members took medications at some time during the
mission. Such medical events often necessitate the use of pharmacologic interventions;
as such, NASA carries a variety of medications during their space missions.
Most medical events reflect short-term adaptation to the weightless space environment, such as space motion sickness, back pain (from spinal cord expansion), nasal congestion and headache (from headward fluid shifts), and insomnia. Medications aimed at ameliorating symptoms associated with these complaints are routinely available to astronauts primarily as tablets and capsules. In addition, a variety of antibiotics are carried in the event of an infection, however, in the history of the US manned spaceflight program, these events have been rare. As mission duration increases, greater attention to the inclusion of pharmacologic countermeasures to long-term medical consequences of spaceflight- bone and muscle loss, immune function changes, and radiation exposure to name a few- will need to be accommodated.
While the use of medications during spaceflight is accepted, little is actually known about how the human body handles (pharmacokinetics) and reacts (pharmacodynamics) to medications in space. Compounding this problem, unfortunately, is the fact that little research has been performed in this area, primarily because it is given low priority at NASA. One small experiment which has been performed involved the oral administration of Extra-Strength Tylenol (650mg) to 3 astronauts during a Shuttle mission. Saliva concentrations of Tylenol were collected following administration. The results suggested that during spaceflight, less Tylenol was reaching the bloodstream, possibly due to less absorption from the gut, greater breakdown by the liver, or other factors. This implied that less drug would be available to treat a headache or fever. Indeed, this theory is supported by anecdotal reports of drugs not working as well about 15% of the time when taken by astronauts in space. This could be due to several factors:
1) Physiologic changes produced by spaceflight: Gut motility decreases in space, which could affect oral drug absorption. The breakdown of drugs in the body by the liver, and their removal by the kidneys, may be altered as well, which may also affect blood levels of a drug. Fluid shifts would also change the distribution of drugs in the body. Finally, sites where drugs work may also undergo changes in space, which may impact how the drug can alter the function of these sites.
2) Drug stability in space: There are many factors that can affect the stability of a medication: humidity, temperature and radiation exposure (including electromagnetic radiation, such as visible light, and ionizing radiation, such as galactic cosmic radiation or solar particle events.) When medications are exposed to any or all of these factors, they are prone to degradation, which can affect their potency and/or safety (if broken down to harmful substances). Medications carried on the Shuttle traditionally have been recycled for use on future missions and are only replaced if used or if their expiration date has been reached. Examination of medications flown for increased degradation has not been performed, despite the probability that degradation is increased, particularly due to cabin and crew exposure to higher levels of ionizing radiation. This may be a significant source of drug ineffectiveness in space. Recently, the pharmacology lab at NASA is proposing a study to examine the stability of drugs flown in space.
3) Crew medical knowledge: Medical knowledge among US astronauts is limited. While physician astronauts do exist, it is more likely that nonmedical personnel will be flying a space mission. During crew training, 16 hours of general medical training, consisting of basic first aid, dental repair and pharmacology, is accomplished weeks before flight. The likelihood of significant medical knowledge retention is remote. Flight surgeon support is part of Mission Control for US missions, but not all medications taken during flight are selected based upon consultation with the surgeons. This is particularly an issue with medications taken for space motion sickness, insomnia and miscellaneous aches and pains, in which astronauts feel that no consultation is necessary. Often several medications are ingested by astronauts, which can pose problems, such as additive effects. For example, drowsiness can be increased with the concomitant administration of space motion sickness medications and medications used to treat insomnia. This can impact crew performance. Moreover, a popular trend among astronauts is the use of herbal medications, which are carried on board in personal paks. There is little control over what medications, herbal or otherwise, are stowed in these personal paks. NASA has hired a clinical pharmacist to improve Flight Surgeon and astronaut medication knowledge. For example, the clinical pharmacist and column author, also a clinical pharmacist, have been drafting medication monographs that will serve as reference for both flight surgeons and, eventually, astronauts to assist them in proper medication selection, dosing and monitoring.
Many questions regarding drug administration in space continue to persist. Ideally, research in this area should be given higher priority. An emphasis on ground-based experiments, followed by judicious in-flight studies, will provide important answers to the issue of drug efficacy and safety in space.
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