NASA officials believe that air bubbles in the liquid rubber insulation of the solid rocket booster nozzles may be the cause for the damage to booster O-rings seen in the last two missions that has delayed the launch of the next mission by up to a month.
In a press conference August 4, NASA officials announced that an investigation had uncovered a change in the manufacturing process for the solid rocket boosters. An excess of liquid rubber insulation, which protects the O-rings from the hot exhaust gases from the booster, may have formed air pockets. These air pockets would allow the exhaust to burn through the insulation and damage the O-rings.
Engineers believe the problem can be corrected on the launch pad, by removing the insulation and reinjecting the correct amount, using a vacuum pump to prevent air pockets from forming. A new launch date has not been set, but is expected to be in late August.
The investigation began when heat damage was noticed on O-rings from the last two shuttle missions, STS-71 in late June and STS-70 in mid July. Investigators found that Thiokol Corporation of Utah had started using a new assembly process for the boosters beginning with the STS-71 boosters.
Astronaut Norm Thagard returned to his "second home," the cosmonaut training facility in Star City, Russia, to a warm welcome and traditional Russian greetings of bread and salt August 9th.
Thagard and Russian cosmonauts Vladimir Dezhurov and Gennady Strekalov, who spent 115 days in space, all but the last few on the Russian space station Mir, returned to Star City for their first public appearance in Russia since the mission. The three were showered with flowers and given dark bread and salt, a Russian tradition.
Thagard used the opportunity to deny reports in the Russian press that he had complained about the food aboard Mir, or any other aspects of life on the station. Those reports claimed that cosmonauts had tired of Thagard's "whining" about life on the nine-year-old station. Thagard said his only complaint was boredom, which set in when some experiments were canceled during the mission.
During ceremonies at Star City, Thagard, Dezhurov, and Strekalov laid wreaths in front of a statue of Yuri Gagarin and listened to speeches by Russian officials, who compared the Mir-Atlantis docking in May with the meeting of the American and Soviet armies on the Elbe river in Germany at the end of World War Two.
A strap-on booster that failed to separate as planned may be the cause of a partial failure of a Delta 2 launch August 5 that left a Korean communications satellite in a lower-than-planned orbit.
The failure was the first ever for the Delta 2, out of 42 launches. Engineers have traced the failure to a solid rocket strap-on booster which failed to separate after it burned out. As a result of the extra mass, the first stage did not accelerate to the planned velocity. The second stage burned longer than planned to compensate, but ran out of fuel before making up the difference.
The third stage of the booster sent the payload, the Koreasat 1 communications satellite, into a 30000-km orbit, instead of the planned 35700-km orbit. Mission controllers plan to use the maneuvering thrusters on the satellite to move the payload into the proper orbit, at the cost of reducing the lifetime of the satellite. As of August 10, controllers had moved the spacecraft into a more circular orbit.
The failure is rare for the Delta, one of the most reliable boosters in the world. According to space expert Jonathan McDowell, only 3 Deltas in the last 25 years, out of 150 launched, have failed to reach orbit.
Officials from Boeing and Khrunichev signed a $190 million contract August 15 that will pay the Russian firm to provide the first on-orbit element of the space station.
The agreement coves the cost to complete, launch, and check out the Functional Energy Block, or FGB, which will serve as the core of the International Space Station. The module will be launched on a Russian Proton rocket in November 1997.
Construction is already underway on the module, which will initially provide power and propulsion to the station. The module passed a critical design review in April, and manufacturing and testing of key components is in progress.
Under current assembly plans, the FGB will be launched first, followed a month later by a shuttle mission which will bring up the first American module, a multiport docking module called Node 1. The station will be ready for habitation by March 1999, and will be completed by June 2002.
Russian officials last week announced plans to go ahead with their Mars 96 mission, restarting an ambitious program of exploration that has been beset with problems.
The Mars 96 mission will be launched on a Proton in November 1996 and arrive at Mars the following year. The spacecraft will enter orbit around the planet and release four small probes that will land on the surface and test soil samples in much the same way as the Viking spacecraft did in 1976, searching for signs of life.
The Mars 96 mission is the first since the Phobos 1 and 2 missions in 1988. Phobos 1 lost contact with Earth on its way to Mars when an incorrect computer command was uploaded. Phobos 2 was lost on approach to Mars's largest moon, Phobos.
Two American spacecraft are set for launch in November 1996 as well. The Mars Global Surveyor, a partial replacement for the failed Mars Observer, will go into orbit around Mars to study its atmosphere and climate. The Mars Pathfinder mission will set a small spacecraft, including a mini-rover named Sojouner, on the Martian surface.
Brewster Shaw, a former astronaut and veteran of three shuttle missions, announced his resignation as director of space shuttle operations August 9. The resignation takes affect November 3.
The 50-year-old Shaw, who has been with NASA since 1978, is resigning for personal reasons. Shaw left the astronaut corps to work in management in 1989.
"This was an extremely difficult decision for me to make," Shaw said. "I feel it is best for me to leave the program now." He did not elaborate on his decision to leave.
Tommy Holloway, current director of Phase One of the International Space Station, has been named the new Manager of the Space Shuttle Program. The new position encompasses all the responsibilities of Shaw's old position.
Two astronomers based in Arizona, using the Hubble Space Telescope, have discovered two to as many as four new satellites of Saturn by taking advantage of a rare orientation of Saturn with respect to the Earth.
Dr. Amanda Bosh, a research scientist at Lowell Observatory in Flagstaff, Arizona, and Andrew Rivkin, a graduate student at the University of Arizona in Tucson, announced the discovery in an International Astronomical Union (IAU) Circular on July 26. They announced the discovery of four new moons, two of which might be close to previously known satellites.
Dr. Robert Jacobson of JPL reported in another IAU Circular on August 8 that two of the moons discovered might correspond to the previously known moons of Pan and Atlas or Prometheus. The other two discoveries appeared to be new satellites.
The discoveries were made in HST images taken in May, during a ring plane crossing, when the plane of Saturn's rings lines up with the Earth. Since the rings may only be one kilometer thick, the rings seem to disappear as seen from Earth, making small satellites much easier to discover.
Another ring plane crossing took place August 10. No discoveries or confirmations had been announced by press time. A third ring plane crossing will occur on February 11, 1996.
A newly-discovered comet currently beyond the orbit of Jupiter may become a spectacular sight for Northern Hemisphere observers in the late winter of 1997, but will not threaten the Earth.
The comet was independently discovered July 23 by Alan Hale in New Mexico and Thomas Bopp in Arizona. The IAU gave the comet the designation 1995 O1, as the first comet discovered in 1995, and was named Hale-Bopp after the two discoverers.
The distance of the comet, the farthest ever discovered by amateurs, coupled with its brightness has led to estimates of its size in the hundreds of kilometers. However, a decrease in its brightness noticed recently may mean the comet was discovered during an outburst, when a cloud of dust around the comet increased its brightness.
The comet is currently best visible in the Southern Hemisphere and lower Northern Hemisphere latitudes. When the comet passes through the inner solar system in early 1997, it may become visible to the naked eye for observers throughout the Northern Hemisphere. The comet will approach no closer than 200 million kilometers to the Earth.
United Space Alliance: Rockwell International and Lockheed Martin have announced plans to create a joint venture to become the prime contractor for the space shuttle program. United Space Alliance will combine Rockwell's expertise in shuttle construction and maintainence with Lockheed Martin's operations experience. The formation of the venture is a response to plans by NASA to consolidate the shuttle program under a single prime contractor. The venture could net contracts worth up to $3 billion a year if selected as the prime contractor.
Panamsat 4 Launched: The Panamsat 4 communications satellite was successfully launched August 3 on an Ariane 4 from French Guiana. The satellite will provide television services for much of Asia, Africa, Europe, and Australia. It will carry some networks, such as TNT and the Cartoon Network, originally to be on Apstar 2. The Apstar 2 satellite was destroyed when its Long March booster exploded after launch in January.
Defense Comsat Launched: An Atlas IIA Centaur placed an American defense communications satellite into orbit July 31. The spacecraft, which belongs to the DSCS III class of comsats, reached geostationary orbit without any known problems. The launch was the first time an Atlas IIA Centaur had been used for a DSCS launch; previous missions used an Atlas II Centaur. The IIA model has more powerful motors than the Atlas II.
An Orbital Resting Place for a Grateful Dead: The National Space Society has announced an effort to place the remains of Jerry Garcia in orbit. The 25,000-member organization plans to ask its members and others to contribute to a special fund to pay for the costs of placing Garcia's remains in an "eternal" orbit, and has already contacted launch agencies to determine the cost. "It seems only fitting that Jerry spend eternity where he belongs -- among the stars," Lori Garver, executive director of the NSS said. Garcia, guitarist for the popular rock group Grateful Dead, passed away in California on August 9.