The shuttle Columbia will fly again this July on a reflight of a microgravity science mission that was cut short last month after only four days in orbit.
     "While shortening STS-83 was disappointing, we now are in a position to do everything possible to complete the MSL [Microgravity Science Laboratory] mission with minimal impact to downstream flights," said shuttle program manager Tommy Holloway April 25.
     The reflight of STS-83 has been manifested for early July, with an exact date to be announced in the near future. The mission, originally informally named STS-83R, was officially redesignated STS-94. STS-94 was originally scheduled as a space station assembly flight for the shuttle Discovery in November 1998.
     The Columbia reflight will slightly delay missions scheduled later in the year. STS-85, the launch of Discovery on an atmospheric science mission, will be pushed back from mid-July to early or mid-August. The launch of the Endeavour on STS-86, the seventh Mir docking mission, will shift back from mid to late September. Another Columbia microgravity research mission, STS-87, will move from early October to early November.
     STS-83 lifted off April 4 on what was scheduled to be a 16-day mission. The Microgravity Science Laboratory-1 mission used the Spacelab module to host several dozen experiments on the effects of weightlessness on plants, materials, and combustion.
     However, one of the three fuel cells in shuttle, used to generate electrical power and drinking water, lost voltage and could not generate sufficient power. After a day of attempts to fix the fuel cell, engineers shut down the fuel cell on April 6 as shuttle managers announced plans to curtail the mission, as required by shuttle guidelines.
     Discussion of a shuttle reflight took place as soon as Columbia landed on April 8, but a reflight was not approved until April 17 and not officially announced until April 25 while shuttle managers discussed concerns about safely turning the shuttle around three months after a mission. "It's ambitious, it's aggressive, but it's doable," said Kennedy Space Center spokesman Bruce Buckingham.

The three men aboard the Russian space station Mir continued to struggle with problems with the space station but still managed do conduct a historic U.S.-Russian spacewalk on April 29.
     The problems with the cooling system, oxygen generators, and carbon dioxide scrubbers at one point caused Russian officials to consider evacuating the crew, based on comments by a Russian official on April 22.
     "The team is continuing its repairs. It's a difficult task and if it cannot be solved Mir might be abandoned by the cosmonauts," Russian Space Agency spokesman Viktor Blagov said, setting off a flurry of reports that the station might soon be evacuated.
     Blagov later denied saying that the situation on Mir was that serious. "We have no intention to evacuate the station," Blagov told The Associated Press. "The Mir is likely to stay in service through 1999."
     NASA officials, while keeping a watchful eye on the situation, did not believe the station was in serious trouble. "Things were rough a couple of weeks ago, but right now they are gradually working back into a fairly nominal situation," said Frank Culbertson, manager of the shuttle-Mir program.
     The Mir crew had been working for several weeks plugging holes in the station's cooling system. The failure of the cooling system forced the carbon dioxide scrubbers offline for some time, but they were later turned back on.
     One oxygen generator on Mir was repaired in mid-April. Both of the primary oxygen generators broke down in early March, forcing the crew to go to a backup system of lithium perchlorate candles. A new oxygen generator will be brought to the station by the shuttle Atlantis in mid-May.
     Despite the problems, astronaut Jerry Linenger and cosmonaut Vasiliy Tsibliev conducted the first joint U.S.-Russian spacewalk from the Mir space station April 29. The two spent five hours outside the station collecting dust samples and installing experiments to measure the radiation environment outside the station and study the effects of space on a number of different materials.
     The spacewalk went well and finished an hour earlier than scheduled when Linenger and Tsibliev finished all their tasks early. The equipment installed by the spacewalkers will be replaced during another spacewalk in June.
     Linenger is wrapping up his four-month stay on Mir. The shuttle Atlantis is scheduled to launch on May 15 to dock with the station and replace Linenger with Michael Foale. Linenger will return to Earth on Atlantis while Foale will spend four months on the station.

The House of Representatives passes a two-year authorizations bill for NASA on April 24 which funds the space agency at a slightly higher level than what President Clinton requested and includes funds for a second X-vehicle program.
     The Civilian Space Authorization Act, H.R. 1275, passed on a voice vote in the House of Representatives on April 24. The bill authorizes $13.8 billion for fiscal year 1998 and $13.9 billion for 1999. This is slightly larger than the $13.5 billion requested by President Clinton for 1998 and $13.4 billion in 1999.
     Included in the House bill is $725 million over two years for a second X-vehicle program dubbed "Future-X" that would test launch technologies "more advanced" than those in use in the current X-33 program.
     Proponents of Future-X had expected a fight to remove that provision from the bill, but the proposal did not encounter stiff opposition. One member expected to fight the project, Rep. Zoe Lofgren (R-CA), contacted the lobbying group ProSpace to notify them that she disagreed with the additional funding but did not plan to fight the provision.
     In a statement sent to ProSpace, Lofgren said her opposition to the project was based on concerns that not all possible X-vehicle options were considered, and that the high level of funding might scare potential private investors away from the X-33.
     However, she also said, "I strongly believe in competition and certainly share the dream of those who seek cheap access to space."
     An attempt to cut funding for the International Space Station, proposed by longtime station opponent Rep. Tim Roemer (D-IN), also failed in a House vote. The amendment to kill the station garnered only 112 yes votes to 305 no votes.
     After passage, the bill passed on to the Senate, which will consider it in upcoming weeks. Later in the Congressional session both houses will take up appropriations bills for the space agency.

A Pegasus rocket launched a Spanish research satellite and a container of ashes for Celestis into orbit on April 21, marking the first launch of a Spanish-built satellite and the first space memorial launch.
     A Pegasus XL, carried by an Orbital Sciences Corporation (OSC) L-1011 jet, launched over the Atlantic Ocean at 8am EDT (1200 UT) April 21. The rocket placed its payload into an orbit 550 km (340 mi.) high and traveling westward, instead of the usual eastward direction.
     The primary payload was MINISAT-1, a 195-kg (430-lb.) satellite that was Spain's first scientific satellite, and the first built wholly within Spain. The satellite has a number of missions, including observations of background radiation at ultraviolet wavelengths, studies of low-energy gamma rays, and the behavior of liquid bridges in weightlessness.
     Also carried into orbit was a container of ashes for Celestis, a Houston-based firm which offers space memorial services. This launch, the first for the company, was billed as the "Founders' Flight" and included remains from Star Trek founder Gene Roddenberry, space colony pioneer Gerard O'Neill, and International Space University cofounder Todd Hawley.
     The ashes, 7 grams (0.25 oz.) per person, were lofted into orbit in a container attached to the top stage of the Pegasus rocket. The container will remain in orbit for up to several years before reentering and burning up in the Earth's atmosphere, "blazing like a shooting star in final tribute," according to Celestis president Chan Tysor.
     Noting that the launch took place off the Canary Islands in the Atlantic Ocean, near Spain, Celestis vice president Charles Chafer said, "How appropriate that these modern explorers begin their journey from the departure point of the explorers of the new world over five hundred years ago."
     The company is planning a second launch of remains on a OSC Taurus rocket later this year. The service is available to the general public for $4,800 per person.

Scientists have found evidence of two large clouds of antimatter located in the Milky Way Galaxy which may be linked to a large black hole in the center of our galaxy or supernova explosions of massive stars.
     Scientists from Northwestern University, the Naval Research Laboratory (NRL), and other institutions used an instrument on the Compton Gamma Ray Observatory to find two clouds of antimatter. One large cloud was found in a region surrounding the center of the galaxy, while a second plume of antimatter extended up to 3,000 light-years above the Milky Way's core.
     The second plume of antimatter was unexpected and has yet to be explained. "The origin of this new and unexpected source of antimatter is a mystery," said Northwestern University physics professor William Purcell.
     James R. Kurfess of NRL outlines three possible sources for the antimatter plume. "The antimatter cloud could have been formed by multiple star bursts occurring in the central region of the galaxy, jets of material from a black hole near the galactic center, the merger of two neutron stars, or it could have been produced by an entirely different source," he said.
     The astronomers used the Oriented Scintillation Spectrometer Experiment (OSSE), one of the instruments on the orbiting gamma-ray observatory. The instrument detects gamma rays produced when positrons, the antimatter version of electrons, come into contact with regular matter and annihilate.
     "It's possible that this mapping effort could turn up evidence for other unexpected clouds of positrons," Kurfess said. "We will keep monitoring the center of the Galaxy in the hope of seeing evidence for a black hole 'turning on' and producing positrons," he added.

NASA announced April 22 that is was suspending its participation in the Bion 12 mission, an international effort to study the effects of weightlessness on plants and animals, after one of the two monkeys that flew on the Bion 11 mission died shortly after landing in January.
     The space agency's decision came after an independent panel conducted a review of the Bion 11 mission and risks to the monkeys flown on that mission. That panel, led by Dr. Ronald Merrell of Yale University, concluded that "there was an unexpected mortality risk associated with anesthesia for surgical procedures (biopsy of bone and muscle) on the day following return from space," according to a NASA press release.
     Two rhesus monkeys, Laptik and Multik, flew on the Bion 11 mission. The mission launched from Russia on Christmas Eve last year and landed two weeks later. The monkeys survived the trip in good health, however, Multik died the following day of cardiac arrest while under anesthesia.
     NASA announced it would "incorporate lessons learned from this mission" into future projects. The agency will also work with biomedical researchers to find alternate, acceptable ways to collect data.
     The Bion 11 mission was a cooperative effort with Russia and France, with Russia contributing much of the equipment as well as the two monkeys. A similar followup mission, Bion 12, was scheduled for launch in 1998.

An Atlas booster launched a weather satellite into orbit on April 25 while an Ariane 4 rocket boosted two Asian communications satellites into orbit on April 16.
     An Atlas I rocket launched the GOES-K weather satellite at 1:49am EDT (0549 UT) on April 25. A Centaur upper stage lifted the satellite into a geostationary transfer orbit. The satellite's kick motor is in the process of circularizing its orbit, which will be completed in early May.
     The launch was the last for the old Atlas I series of boosters, which are being retired. The launch was pushed back one day due to strong storms around the Cape Canaveral launch site.
     Once in its final orbit, the satellite will be renamed GOES-10. It will not be put into immediate operation but instead serve as an on-orbit spare for the two current GOES spacecraft, GOES-8 and GOES-9. This allows it to be placed into use much faster than storing it on the ground and launching it only when one of the current satellites fails.
     An Ariane 44LP booster launched two communications satellites from its launch site in Kourou, French Guiana on April 16. The booster successfully placed Thaicom-3 and BSAT-1a into orbit after a launch at 7:09pm EDT (2309 UT).
     Thaicom-3 will provide communications and direct television services for Thailand. BSAT-1a will be used by Broadcasting Satellite System Corporation to provide direct broadcast television to 10 million customers in Japan.

NASA released on April 23 a list of five candidate missions for the Discovery series of low-cost science missions which will receive funds for further study.
     "The selected concepts include a mission to a planet, Mercury, that we have not visited with a spacecraft in more than two decades, interesting complements to our currently planned cometary and Mars robotic missions, and the first attempt to gather a sample of particles from the Sun and bring them back to Earth," said Wesley Huntress, associate administrator for space science.
     Messenger, the Mercury Surface, Space Environment, Geochemistry and Ranging mission, would go into orbit around the innermost planet and return images and other data about the planet. VESAT, the Venus Environmental Satellite, would go into orbit around Venus and study its atmosphere.
     The moons of Mars would be targeted by Aladdin, which would fire projectiles into the moons and gather ejecta from the impacts during flybys, which would be returned to Earth for analysis. Another selected sample return mission is Genesis, which would collect samples of the solar wind and return them to Earth.
     CONTOUR, the Comet Nucleus Tour, would visit at least three comets and take images of their nuclei and the dust flowing around them to learn more about their composition.
     Each of the five selected proposals will receive a $350,000 grant to conduct an in-depth four-month study about the mission. One or two of the proposed missions will be selected by NASA in October as the next Discovery missions.
     Discovery missions are intended to be inexpensive, fast-track science missions that are more flexible than older, high-cost missions like Galileo and Cassini. Proposals selected in this round of the Discovery program must meet a cost cap of $183 million and be ready to launch by September 2002.
     Four spacecraft have been selected for Discovery missions to date. Two of them, the Near-Earth Asteroid Rendezvous and Mars Pathfinder, have already been launched. Lunar Prospector will be launched this fall and Stardust will be launched in February 1999.

Two separate groups of astronomers reported progress on two of the biggest current problems in astronomy and cosmology: the amount and type of dark matter in the universe and the age paradox where certain star clusters contain stars older than the age of the universe.
     Neill Reid, an astronomer at Caltech, used data from the European satellite Hipparcos to show that globular clusters contain stars no older than 11 to 13 billion years old, not the 16 to 18 billion year age previously thought.
     Reid used precise measurements of nearby star positions from the Hipparcos satellite as "standard candles" by which to judge the distance of similar but more distant stars. He found that the clusters are 10 to 15 percent farther away than once though, hence about 20 percent brighter. Since brighter stars have shorter lifespans, Reid concluded the stars were several billion years younger than previously estimated.
     "Most people previously believed that 14 billion years was the youngest age you could have for these stars," Reid said. "I think it's now accurate to say that the oldest you could make them is 14 billion years."
     This helps resolve a paradox where other estimates of the age of the universe made the universe no more than 13 billion years old, or much younger than some of the clusters within it.
     Astrophysicists Arthur F. Davidsen and HongGuang Bi at the Johns Hopkins University announced April 18 that they believe that much of the missing matter in the universe consists of diffuse clouds of hydrogen and helium in intergalactic space.
     Davidsen and Bi started with data from the Hopkins Ultraviolet Telescope (HUT), flown on the Astro-2 shuttle mission, which showed a much wider distribution of primordial helium than originally thought. Through a series of "fairly simple analytical equations," the two astrophysicists showed that hydrogen and helium must be widespread in intergalactic space. The gases are not seen in the expected amounts since ultraviolet light from quasars and other sources strips away electrons, making it difficult to observe them with normal spectroscopy.
     "The gas is so highly ionized that we are seeing only the tail of the dog," Davidsen said. "It's a big dog but we are only seeing the tail. If we had a theory that told us exactly what dog it is, based on what the tail looks like, then we could say something. That's what we have now -- a theory that connects the tail to the dog."

Another New Planet: A team of astronomers at the Smithsonian Astrophysical Observatory (SAO) have found yet another new planet, this time around the star Rho Coronae Borealis. The team found a periodic variation in the velocity of the star, a Sun-like body about 50 light-years from the Earth. The planet is estimated to be slightly more massive than Jupiter and orbits only 1/4th as far from the Sun as the Earth, completing an orbit in just 40 days. The orbit is circular, though, which leads the team to believe the planet formed like the planets in our solar system. The SAO team worked with people from the National Center for Atmospheric Research and Penn State University on the research, which will be published in the journal Astrophysical Journal Letters.

Boeing Buys In: Boeing has bought a ten percent share of Teledesic, the satellite communications firm largely owned by Bill Gates and Craig McCaw. The aerospace giant will invest up to $100 million into the Kirkland, Washington firm and will become the prime contractor for the system, which will place several hundred satellites in low-Earth orbit to provide high-speed communications worldwide. "Boeing shares Teledesic's vision of building a global satellite network that will extend the most advanced information services to the far reaches of the earth," said Boeing president Phil Condit. The value of the contract may reach $9 billion.

Russia Antes Up: The Russian space agency has raised the $140 million it needs to build the Service Module, a key piece of the International Space Station which has been delayed for up to 11 months due to problems securing funding to complete its construction. Four private Russian banks will loan the money to the space agency, Russian space agency head Yuri Koptev said April 29. The loans will be finalized by mid-May.

Cassini at KSC: The Cassini spacecraft arrived at the Kennedy Space Center April 21. Technicians will now add the last of the dozen scientific instruments to the spacecraft as well as the European-built Huygens probe, and conduct final integration tests. Cassini is slated for an October launch on a Titan IVB rocket from the space center.

In Brief: An Apt retirement: astronaut Jay Apt announced his plans to leave the astronaut corps in late May. The four-time shuttle astronaut will become director of the Carnegie Museum of Natural History in Pittsburgh... Tom Hanks is hard at work as executive director of "From the Earth to the Moon", HBO's $50 million 13-part drama about the space program through the Apollo moon landings. Hanks, who is also directing one of the segments, told CNN, "I'm continuously and repeatedly inspired by the whole shebang."... Israel has selected a payload specialist for a future shuttle mission. The catch: his identity has not been revealed, since he is an Israeli Air Force fighter pilot, and the nation holds the identity of its pilots in strict secrecy. Perhaps he can wear a helmet for the whole mission... Last month we reported that a meteorite apparently hit a car in Chambery, France, setting it on fire. Later analysis of the hunk of material by the Paris Museum's Claude Perron has shown the object was... a piece of combustible plastic.