In July 1994, the comet Shoemaker-Levy 9 (SL9) hit Jupiter and left visible scars on the Jovian disk for weeks. This spectacular event was the first direct observation of an extraterrestrial collision in the solar system, and it was followed worldwide by professional and amateur astronomers.
SL9 was discovered orbiting Jupiter by astronomers David Levy and Carolyn and Eugene M. Shoemaker on March 24, 1993. It was the first comet observed orbiting a planet rather than the Sun. SL9 was found to be composed of 21 fragments. Soon after that, orbital studies showed that the comet had passed within Jupiter’s Roche limit in July 1992. Inside this limit, the planet’s tidal forces are strong enough to disintegrate a body held together by its own gravity, thus explaining SL9’s fragmentation. Even more interestingly, the studies showed that SL9’s orbit would pass within Jupiter in July 1994 and that the comet would then collide with the planet, with impacts in the southern hemisphere near 44°S latitude.
The SL9 impact and its subsequent scars on Jupiter were observed for weeks, but its chemical impact on Jupiter’s atmosphere lasted even longer. Emission from water vapor was observed during the fireball phase of the SL9 impacts, but from that observation, it was difficult to assess how this would modify Jupiter’s composition on the long term. In 1997, the ESA Infrared Space Observatory (ISO) detected water vapor in the stratosphere of Jupiter. At that time, astronomers suspected that it might be a consequence of the SL9 impact because comets are known to be water-rich bodies. However, there were other possible sources of water: interplanetary dust particles produced by cometary activity and asteroid collisions, icy rings, or one of the 60 Jovian satellites.
Nearly twenty years after this major impact, astronomers are still observing its consequences on Jupiter. T. Cavalié and his colleagues  observed Jupiter with the ESA Herschel Space Observatory, which is sensitive enough to map the abundance of water vs. latitude and altitude in the Jovian stratosphere. These observations, which have now been published inAstronomy & Astrophysics, show a clear north-south asymmetry in the distribution of water, with more water in the south. They indicate that 95% of the water currently observed on Jupiter comes from the comet.
 The team includes T. Cavalié, H. Feuchtgruber, E. Lellouch, M. de Val-Borro, C. Jarchow, R. Moreno, P. Hartogh, G. Orton, T. Greathouse, F. Billebaud, M. Dobrijevic, L. Lara, A. Gonzalez, and H. Sagawa.
Spatial distribution of water in the stratosphere of Jupiter from Herschel HIFI and PACS observations, by T. Cavalié, H. Feuchtgruber, E. Lellouch, M. de Val-Borro, C. Jarchow, R. Moreno, P. Hartogh, G. Orton, T. Greathouse, F. Billebaud, M. Dobrijevic, L. Lara, A. Gonzalez, and H. Sagawa.
Published in Astronomy & Astrophysics, 2013, vol. 553, A21
Company Targets April 17 for Inaugural Launch of America’s Newest Medium-Class Space Launch Vehicle
Early this morning, Orbital Sciences Corporation (NYSE: ORB) rolled out the first fully integrated Antares(TM) rocket from its assembly building at NASA’s Wallops Flight Facility (WFF) in eastern Virginia in preparation for its inaugural flight that is scheduled for April 17 at approximately 5:00 p.m. (EDT). This morning, beginning at about 4:30 a.m., the Antares rocket was transported about one mile to the Mid-Atlantic Regional Spaceport (MARS) launch pad complex aboard the Transporter/Erector/Launcher (TEL), a specialized vehicle that also raises the rocket to a vertical position on the launch pad and serves as a support interface between the rocket and the launch complex’s systems.
“With the completion of the Antares roll out today, we are on a clear path to a launch date of April 17, provided there are no significant weather disruptions or major vehicle check-out delays between now and then,” said Mr. Michael Pinkston, Orbital’s Antares Program Manager. “By later today, the Antares rocket will be in a vertical position and fully integrated with the launch mount on the MARS pad.”
The Antares test flight, dubbed the A-ONE mission, is the first of two missions Orbital is scheduled to conduct in 2013 under its Commercial Orbital Transportation Services (COTS) Space Act Agreement with NASA. Following a successful A-ONE launch, Orbital will carry out a full flight demonstration of its new Antares/Cygnus cargo delivery system to the International Space Station (ISS) around mid-year. In addition, the company is also scheduled to launch the first of eight operational cargo resupply missions to the ISS in 2013 under the Commercial Resupply Services (CRS) contract with NASA. All COTS and CRS flights will originate from NASA’s WFF, which is geographically well suited for ISS missions and can also accommodate launches of scientific, defense and commercial satellites to other orbits.
The Antares medium-class launch system will provide a major increase in the payload launch capability that Orbital can provide to NASA, the U.S. Air Force and other customers. The Antares rocket will launch spacecraft weighing up to 14,000 lbs. into low-Earth orbit, as well as lighter-weight payloads into higher-energy orbits. Orbital’s newest launcher is currently on-ramped to both the NASA Launch Services-2 and the U.S. Air Force’s Orbital/Suborbital Program-3 contracts, enabling the two largest U.S. government space launch customers to order Antares for “right-size and right-price” launch services for medium-class spacecraft.
Orbital develops and manufactures small- and medium-class rockets and space systems for commercial, military and civil government customers. The company’s primary products are satellites and launch vehicles, including low-Earth orbit, geosynchronous-Earth orbit and planetary exploration spacecraft for communications, remote sensing, scientific and defense missions; human-rated space systems for Earth-orbit, lunar and other missions; ground- and air-launched rockets that deliver satellites into orbit; and missile defense systems that are used as interceptor and target vehicles. Orbital also provides satellite subsystems and space-related technical services to U.S. Government agencies and laboratories.
More information about Orbital can be found at http://www.orbital.com
The positions of the planets next month will mean diminished communications between Earth and NASA’s spacecraft at Mars.
Mars will be passing almost directly behind the sun, from Earth’s perspective. The sun can easily disrupt radio transmissions between the two planets during that near-alignment. To prevent an impaired command from reaching an orbiter or rover, mission controllers at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., are preparing to suspend sending any commands to spacecraft at Mars for weeks in April. Transmissions from Mars to Earth will also be reduced.
The travels of Earth and Mars around the sun set up this arrangement, called a Mars solar conjunction, about once every 26 months.
“This is our sixth conjunction for Odyssey,” said Chris Potts of JPL, mission manager for NASA’s Mars Odyssey, which has been orbiting Mars since 2001. “We have plenty of useful experience dealing with them, though each conjunction is a little different.”
The Mars solar conjunctions that occur once about every 26 months are not identical to each other. They can differ in exactly how close to directly behind the sun Mars gets, and they can differ in how active the sun is. The sun’s activity, in terms of sunspots and solar flares, varies on a 22-year cycle.
This year, the apparent angle between Mars and the sun (if you could see Mars against the glare of the sun–but don’t try, because it’s dangerous to the eyes) will slim to 0.4 degree on April 17. The sun is in a more active period of solar flares for its current cycle, compared to the 2011 conjunction, but this cycle has been relatively mild.
“The biggest difference for this 2013 conjunction is having Curiosity on Mars,” Potts said. Odyssey and the Mars Reconnaissance Orbiter relay almost all data coming from Curiosity and the Mars Exploration Rover Opportunity, as well as conducting the orbiters’ own science observations.
Transmissions from Earth to the orbiters will be suspended while Mars and the sun are two degrees or less apart in the sky, from April 9 to 26, with restricted commanding during additional days before and after. Both orbiters will continue science observations on a reduced basis compared to usual operations. Both will receive and record data from the rovers. Odyssey will continue transmissions Earthward throughout April, although engineers anticipate some data dropouts, and the recorded data will be retransmitted later.
The Mars Reconnaissance Orbiter will go into a record-only mode on April 4. “For the entire conjunction period, we’ll just be storing data on board,” said Deputy Mission Manager Reid Thomas of JPL. He anticipates that the orbiter could have about 40 gigabits of data from its own science instruments and about 12 gigabits of data from Curiosity accumulated for sending to Earth around May 1.
NASA’s Mars Exploration Rover Opportunity is approaching its fifth solar conjunction. Its team will send no commands between April 9 and April 26. The rover will continue science activities using a long-term set of commands to be sent beforehand.
“We are doing extra science planning work this month to develop almost three weeks of activity sequences for Opportunity to execute throughout conjunction,” said Opportunity Mission Manager Alfonso Herrera of JPL. The activities during the conjunction period will not include any driving.
Curiosity, the newest asset on Mars, can also continue making science observations from the location where it will spend the conjunction period. Curiosity’s controllers plan to suspend commanding from April 4 to May 1.
“We will maintain visibility of rover status two ways,” said Torsten Zorn of JPL, conjunction planning leader for the mission’s engineering operations team. “First, Curiosity will be sending daily beeps directly to Earth. Our second line of visibility is in the Odyssey relays.”
JPL, a division of the California Institute of Technology, manages the projects operating both NASA Mars orbiters and both Mars rovers for NASA’s Science Mission Directorate, Washington.
NASA and the Department of the Interior’s U.S. Geological Survey (USGS) have released the first images from the Landsat Data Continuity Mission (LDCM) satellite, which was launched Feb. 11.
The natural-color images show the intersection of the United States Great Plains and the Front Range of the Rocky Mountains in Wyoming and Colorado. In the images, green coniferous forests in the mountains stretch down to the brown plains with Denver and other cities strung south to north.
LDCM acquired the images at about 1:40 p.m. EDT March 18. The satellite’s Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) instruments observed the scene simultaneously. The USGS Earth Resources Observation and Science Center in Sioux Falls, S.D., processed the data.
“We are very excited about this first collection of simultaneous imagery,” said Jim Irons, LDCM project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “These images confirm we have two healthy, functioning sensors that survived the rigors of launch and insertion into Earth orbit.”
Since launch, LDCM has been going through on-orbit testing. The mission operations team has completed its review of all major spacecraft and instrument subsystems, and performed multiple spacecraft attitude maneuvers to verify the ability to accurately point the instruments.
The two LDCM sensors collect data simultaneously over the same ground path. OLI collects light reflected off the surface of Earth in nine different regions of the electromagnetic spectrum, including bands of visible light and near-infrared and short-wave-infrared bands, which are beyond human vision. TIRS collects data at two longer wavelength thermal infrared bands that measure heat emitted from the surface.
By looking at different band combinations, scientists can distinguish features on the land surface. These features include forests and how they respond to natural and human-caused disturbances, and the health of agricultural crops and how much water they use. Data from LDCM will extend a continuous, 40-year-long data record of Earth’s surface from previous Landsat satellites, an unmatched, impartial perspective that allows scientists to study how landscapes all across the world change through time.
“These first scenes from the new Landsat satellite continue the remarkable output from the Landsat program with better, more useful imagery and information,” said Matthew C. Larsen, associate director for climate and land use change at the U.S. Geological Survey in Reston, Va. “We are gratified that this productive partnership between USGS and NASA has maintained the continuity and utility of this essential satellite tool, providing the foundation for land and water management around the globe.”
As planned, LDCM currently is flying in an orbit slightly lower than its operational orbit of 438 miles (705 kilometers) above Earth’s surface. As the spacecraft’s thrusters raise its orbit, the NASA-USGS team will take the opportunity to collect imagery while LDCM is flying under Landsat 7, also operating in orbit. Measurements collected simultaneously from both satellites will allow the team to cross-calibrate the LDCM sensors with Landsat 7’s Enhanced Thematic Mapper-Plus instrument.
“So far, our checkout activities have gone extremely well,” said Ken Schwer, LDCM project manager at Goddard. “The mission operations team has done a tremendous job getting us to the point of imaging Earth.” During the next few weeks, this team will calibrate the instruments and verify they meet performance specifications.
After its checkout and commissioning phase is complete, LDCM will begin its normal operations in May. At that time, NASA will hand over control of the satellite to the USGS, which will operate it throughout its planned five-year mission life. The satellite will be renamed Landsat 8. USGS will process data from OLI and TIRS and add it to the Landsat Data Archive at the USGS Earth Resources Observation and Science Center, where it will be distributed for free via the Internet.
For more information on these first LDCM images, visit: http://go.nasa.gov/13cHhFJ
For more information on the LDCM mission, visit: http://www.nasa.gov/landsat
International Space Station Size & Mass
- Module Length: 167.3 feet (51 meters)
- Truss Length: 357.5 feet (109 meters)
- Solar Array Length: 239.4 feet (73 meters)
- Mass: 924,739 pounds (419,455 kilograms)
- Habitable Volume: 13,696 cubic feet (388 cubic meters)
- Pressurized Volume: 32,333 cubic feet (916 cubic meters)
- Power Generation: 8 solar arrays = 84 kilowatts
- Lines of Computer Code: approximately 2.3 million
- The ISS solar array surface area could cover the U.S. Senate Chamber three times over.
- ISS has an internal pressurized volume of 32,333 cubic feet, or equal that of a Boeing 747.
- The solar array wingspan (240 feet) is longer than that of a Boeing 777 200/300 model, which is 212 feet.
- Fifty-two computers control the systems on the ISS.
- More than 115 space flights were conducted on five different types of launch vehicles over the course of the station’s construction.
- More than 100 telephone-booth-sized rack facilities can be in the ISS for operating the spacecraft systems and research experiments.
- The ISS is almost four times as large as the Russian space station Mir and about five times as large as the U.S. Skylab.
- The ISS weighs almost one million pounds (approximately 925,000 pounds). That’s the equivalent of more than 320 automobiles.
- The ISS measures 357 feet end-to-end.
- 3.3 million lines of software code on the ground support 1.8 million lines of flight software code.
- Eight miles of wire connects the electrical power system.
- In the International Space Station’s U.S. segment alone, 1.5 million lines of flight software code run on 44 computers communicating via 100 data networks transferring 400,000 signals (e.g. pressure or temperature measurements, valve positions, etc.).
- The ISS manages 20 times as many signals as the space shuttle.
- Main U.S. control computers have 1.5 gigabytes of total main hard drive storage in the U.S. segment compared to modern PCs, which have ~500 gigabyte hard drives.
- The entire 55-foot robot arm assembly is capable of lifting 220,000 pounds, which is the weight of a space shuttle orbiter.
- The 75 to 90 kilowatts of power for the ISS is supplied by an acre of solar panels.
Question: What is a Quasar?
The word “quasar” refers to a “quasi-stellar radio source.”
The first quasars were discovered in the 1960s when astronomers measured their very strong radio emissions. Later, scientists discovered that quasars are actually radio-quiet, with very little radio emission. However, quasars are some of the brightest and most distant objects we can see.
These ultra-bright objects are likely the centres of active galaxies where supermassive black holes reside. As material spirals into the black holes, a large part of the mass is converted to energy. It is this energy that we see and though smaller than our solar system, a single quasar can outshine an entire galaxy of a hundred billion stars. This is particularly impressive when you consider that most quasars are known to be farther than three billion light-years away!
More than 200,000 quasars are known, most from the Sloan Digital Sky Survey.
Question: Why do Stars Twinkle?
Stars twinkle because their light must pass through pockets of Earth’s atmosphere that vary in temperature and density, and it’s all very turbulent. On rough nights, a star appears to shift position constantly as its light is refracted this way and that.
One could liken it to watching a coin appear to dance at the bottom of a pool, it gives the impression of movement when it is stationary.
To overcome the twinkling Astronomers use adaptive optics, in which many small mirrors on the scope adjust constantly to allow for the atmospheric disturbances. They can also use space-based telescopes to make observations. Of course, telescopes orbiting Earth above the atmosphere avoid the problems caused by turbulence.
Awesomeness! Felix has done it … the world’s highest freefall record is his. Mint!
What a rush! I have total respect to all involved, what an exciting achievement. It’s my hope this is just the beginning of Corporate Sponsored Science, and that future projects will benefit from the undoubted excitement the RedBull Stratos project has brought about. It proves that Science is Awesome. Hopefully kids will now be pestering their parents for all sorts of kit for Christmas, and if you are a parent then go out and buy your kid a science kit, a home rocket, anything to really ‘get them involved’.
Too often we complain about our schools not doing enough to help young entrepreneurs, thinkers, inventors, experimentors, artists, musicians and dancers. Well I challenge you dear reader to do something about it!
Get out there, do something yourself. Create, imagine, and encourage others to do the same! Make it your goal next week to speak positively about a scientific subject to your work colleagues. Parents this is a fantastic opportunity to encourage your children, who knows they could be the next Einstein, Newton, Darwin or Faraday.
Don’t procrastinate, experiment, learn, and share!
Suomi NPP is NASA’s next Earth-observing research satellite. It is the first of a new generation of satellites that will observe many facets of our changing Earth.
The first thing that strikes you about the images is of course the depth and clarity of the detail. It is fantastic. Next is the sheer beauty of the image before your eyes. What a beautiful jewel of a planet you live on. This will stir many emotions in differing ways.
For me there is sadness at the damage mankind is inflicting upon our home world, mixed with admiration for the science behind getting these images, hand-in-hand with the knowledge that someday the inhabitants of this jewel will find themselves travelling to equally beautiful planets elsewhere in the vastness of space.
Over the last decade NASA has launched a series of satellites that offer us an unparalleled view of Earth from space. This series of Satellites are known collectively as NASA’s Earth Observing System (EOS). They have provided striking new insights into many aspects of Earth, including its clouds, oceans, vegetation, ice, and atmosphere. However, as we know technology does not stand still so as the EOS satellites age, a new generation of Earth-observing satellites are poised to take over.
The Suomi National Polar-orbiting Partnership represents a critical first step in building this next-gen satellite system. Suomi NPP orbits the Earth about 14 times each day and observe nearly the entire surface.
The NPP satellite continues key data records that are critical for climate change science, almost a year ago now, the launch at 5:48 a.m. EDT on 28th Oct 2011, capped a flawless countdown to begin its Earth observation mission.
Below are some of the latest images:
|Click to enlarge images||All images copyright NASA||and the respective owners|
To find out more about this and other missions, head over to the NASA website and get clued up.
To see more of these amazing images, head over to the NPP Suomi Flickr page.