Artist depiction of Huygens landing on Titan. Credit: ESA
Twelve years ago today, the Huygens probe landed on Titan, marking the farthest point from Earth any spacecraft has ever landed. While a twelfth anniversary may be an odd number to mark with a special article, as we said in our previous article (with footage from the landing), this is the last opportunity to celebrate the success of Huygens before its partner spacecraft Cassini ends its mission on September 15, 2017 with a fateful plunge into Saturn’s atmosphere.
But Huygens is also worth celebrating because, amazingly, the mission almost failed, but yet was a marvelous success. If not for the insistence of one ESA engineer to complete an in-flight test of Huygens’ radio system, none of the spacecraft’s incredible data from Saturn’s largest and mysterious moon would have ever been received, and likely, no one would have ever known why.
The first-ever images of the surface Titan, taken by the Huygens probe. Image Credit: ESA/NASA/JPL/University of Arizona
As I detail in my new book “Incredible Stories From Space: A Behind-the-Scenes-Look at the Missions Changing Our View of the Cosmos,” in 1999, the Cassini orbiter and the piggybacking Huygens lander were on their way to the Saturn system. The duo launched in 1997, but instead of making a beeline for the 6th planet from the Sun, they took a looping path called the VVEJGA trajectory (Venus-Venus-Earth-Jupiter Gravity Assist), swinging around Venus twice and flying past Earth 2 years later.
While all the flybys gave the spacecraft added boosts to help get it to Saturn, the Earth flyby also provided a chance for the teams to test out various systems and instruments and get immediate feedback.
“The European group wanted to test the Huygens receiver by transmitting the data from Earth,” said Earl Maize, Project Manager for the Cassini mission at JPL, who I interviewed for the book. “That’s a great in-flight test, because there’s the old adage of flight engineers, ‘test as you fly, fly as you test.’”
The way the Huygens mission would work at the Saturn system was that Cassini would release Huygens when the duo approached Titan. Huygens would drop through Titan’s thick and obscuring atmosphere like a skydiver on a parachute, transmitting data all the while. The Huygens probe didn’t have enough power or a large enough dish to transmit all its data directly to Earth, so Cassini would gather and store Huygens’ data on board and later transmit it to Earth.
Boris Smeds was head of ESOC’s Systems and Requirements Section, Darmstadt, Germany. Credit: ESA.
ESA engineer Boris Smeds wanted to ensure this data handoff was going to work, otherwise a crucial part of the mission would be lost. So he proposed a test during the 1999 Earth flyby.
Maize said that for some reason, there was quite a bit of opposition to the test from some of the ESA officials, but Smeds and Claudio Sollazzo, Huygens’s ground operations manager at ESA’s European Space Operation Centre (ESOC) in Darmstadt, Germany were insistent the test was necessary.
NASA’s Deep Space Network is responsible for communicating with spacecraft. Pictured is the Goldstone facility in California, one of three facilities that make up the Network. Image: NASA/JPL
“They were not to be denied,” Maize said, “so they eventually got permission for the test. The Cassini team organized it, going to the Goldstone tracking station [in California] of the Deep Space Network (DSN) and did what’s called a ‘suitcase test,’ broke into the signal, and during the Earth flyby, Huygens, Cassini and Goldstone were all programmed to simulate the probe descending to Titan. It all worked great.”
Except for one thing: Cassini received almost no simulated data, and what it did receive was garbled. No one could figure out why.
Six months of painstaking investigation finally identified the problem. The variation in speed between the two spacecraft hadn’t been properly compensated for, causing a communication problem. It was as if the spacecraft were each communicating on a different frequency.
Artist concept of the Huygens probe descending to Titan. Credit: ESA.
“The European team came to us and said we didn’t have a mission,” Maize said. “But we put together ‘Tiger Teams’ to try and figure it out.”
The short answer was that the idiosyncrasies in the communications system were hardwired in. With the spacecraft now millions of miles away, nothing could be fixed. But engineers came up with an ingenious solution using a basic principal known as the Doppler Effect.
The metaphor Maize likes to use is this: if you are sitting on the shore and a speed boat goes by close to the coast, it zooms past you quickly. But that same boat going the same speed out on the horizon looks like it is barely moving.
“Since we couldn’t change Huygens’ signal, the only thing we could change was the way Cassini flew,” Maize said. “If we could move Cassini farther away and make it appear as if Huygens was moving slower, it would receive lander’s radio waves at a lower frequency, solving the problem.”
Maize said it took two years of “fancy coding modifications and some pretty amazing trajectory computations.” Huygens’ landing was also delayed two months for the new trajectory that was needed overcome the radio system design flaw.
Additionally, with Cassini needing to be farther away from Huygens than originally planned, it would eventually fly out of range to capture all of Huygens’ data. Astronomers instigated a plan where radio telescopes around the world would listen for Huygens’ faint signals and capture anything Cassini missed.
Huygens was released from the Cassini spacecraft on Christmas Day 2004, and arrived at Titan on January 14, 2005. The probe began transmitting data to Cassini four minutes into its descent through Titan’s murky atmosphere, snapping photos and taking data all the while. Then it touched down, the first time a probe had landed on an extraterrestrial world in the outer Solar System.
Because of the communication problem, Huygens was not able to gather as much information as originally planned, as it could only transmit on one channel instead of two. But amazingly, Cassini captured absolutely all the data sent by Huygens until it flew out of range.
“It was beautiful,” Maize said, “I’ll never forget it. We got it all, and it was a wonderful example of international cooperation. The fact that 19 countries could get everything coordinated and launched in the first place was pretty amazing, but there’s nothing that compares to the worldwide effort we put into recovering the Huygens mission. From an engineering standpoint, that might trump everything else we’ve done on this mission.”
The view of Titan from the descending Huygens spacecraft on January 14, 2005. Credit: ESA/NASA/JPL/University of Arizona.
With its ground-breaking mission, Huygens provided the first real view of the surface of Titan. The data has been invaluable for understanding this unique and mysterious moon, showing geological and meteorological processes that are more similar to those on the surface of the Earth than anywhere else in the Solar System. ESA has details on the top discoveries by Huygens here.
Noted space journalist Jim Oberg has written several detailed and very interesting articles about the Huygens’ recovery, including one at IEEE Spectrum and another at The Space Review. These articles provide much more insight into the test, Smeds’ remarkable insistence for the test, the recovery work that was done and the subsequent success of the mission.
As Oberg says in IEEE Spectrum, “Smeds continued a glorious engineering tradition of rescuing deep-space missions from doom with sheer persistence, insight, and lots of improvisation.”
A modest Smeds was quoted by ESA: “This has happened before. Almost any mission has some design problem,” says Smeds, who says he’s worked on recovering from pre- and post-launch telecom issues that have arisen with several past missions. “To me, it’s just part of my normal work.”
For more stories about Huygens, Cassini and several other current robotic space missions, “Incredible Stories From Space” tells many behind-the-scenes stories from the amazing people who work on these missions.
The International Space Station orbiting Earth. Credit: NASA
After the historic Apollo Missions, which saw humans set foot on another celestial body for the first time in history, NASA and the Russian Space Agency (Roscosmos) began to shift their priorities away from pioneering space exploration and began to focus on developing long-term capabilities in space. In the ensuing decades (from the 1970s to 1990s), both agencies began to build and deploy space stations, each one bigger and more complex than the last.
The latest and greatest of these is the International Space Station (ISS), a scientific facility that resides in Low-Earth Orbit around our planet. This space station is the largest and most sophisticated orbiting research facility ever built and is so large that it can actually be seen with the naked eye. Central to its mission is the idea of fostering international cooperation for the sake of advancing science and space exploration.
Origin:
Planning for the ISS began in the 1980s and was based in part on the successes of Russia’s Mir space station, NASA’s Skylab, and the Space Shuttle Program. This station, it was hoped, would allow for the future utilization of low-Earth Orbit and its resources, and serve as an intermediate base for renewed exploration efforts to the Moon, mission to Mars, and beyond.
The Mir space station hangs above the Earth in 1995 (photo taken by the mission crew of the Space Shuttle Atlantis, STS-71). Credit: NASA
In May of 1982, NASA established the Space Station task force, which was charged with creating a conceptual framework for such a space station. In the end, the ISS plan that emerged was a culmination of several different plans for a space station – which included NASA’s Freedom and the Soviet’s Mir-2 concepts, as well as Japan’s Kibo laboratory, and the European Space Agency’s Columbus laboratory.
The Freedom concept called for a modular space station to be deployed to orbit, where it would serve as the counterpart to the Soviet Salyut and Mir space stations. That same year, NASA approached the Japanese Aerospace and Exploration Agency (JAXA) to participate in the program with the creation of the Kibo, also known as the Japanese Experiment Module.
The Canadian Space Agency was similarly approached in 1982 and was asked to provide robotic support for the station. Thanks to the success of the Canadarm, which was an integral part of the Space Shuttle Program, the CSA agreed to develop robotic components that would assist with docking, perform maintenance, and assist astronauts with spacewalks.
In 1984, the ESA was invited to participate in the construction of the station with the creation of the Columbus laboratory – a research and experimental lab specializing in materials science. The construction of both the Kibo and Columbus modules was approved in 1985. As the most ambitious space program in either agency’s history, the development of these laboratories was seen as central to Europe and Japan’s emerging space capability.
Skylab, America’s First manned Space Station. Photo taken by departing Skylab 4 crew in Feb. 1974. Credit: NASA
In 1993, American Vice-President Al Gore and Russian Prime Minister Viktor Chernomyrdin announced that they would be pooling the resources intended to create Freedom and Mir-2. Instead of two separate space stations, the programs would be working collaboratively to create a single space station – which was later named the International Space Station.
Construction:
Construction of the ISS was made possible with the support of multiple federal space agencies, which included NASA, Roscosmos, JAXA, the CSA, and members of the ESA – specifically Belgium, Denmark, France, Spain, Italy, Germany, the Netherlands, Norway, Switzerland, and Sweden. The Brazilian Space Agency (AEB) also contributed to the construction effort.
The orbital construction of the space station began in 1998 after the participating nations signed the Space Station Intergovernmental Agreement (IGA), which established a legal framework that stressed cooperation based on international law. The participating space agencies also signed the Four Memoranda of Understandings (MoUs), which laid out their responsibilities in the design, development, and use of the station.
The assembly process began in 1998 with the deployment of the ‘Zarya’ (“Sunrise” in Russian) Control Module, or Functional Cargo Block. Built by the Russians with funding from the US, this module was designed to provide the station’s initial propulsion and power. The pressurized module – which weighed over 19,300 kg (42,600 pounds) – was launched aboard a Russian Proton rocket in November 1998.
On Dec. 4th, the second component – the ‘Unity’ Node – was placed into orbit by the Space Shuttle Endeavour (STS-88), along with two pressurized mating adapters. This node was one of three – Harmony and Tranquility being the other two – that would form the ISS’ main hull. On Sunday, Dec. 6th, it was mated to Zarya by the STS-88 crew inside the shuttle’s payload bay.
The next installments came in the year 2000, with the deployment of the Zvezda Service Module (the first habitation module) and multiple supply missions conducted by the Space Shuttle Atlantis. The Space Shuttle Discovery (STS-92) also delivered the station’s third pressurized mating adapted and a Ku-band antenna in October. By the end of the month, the first Expedition crew was launched aboard a Soyuz rocket, which arrived on Nov. 2nd.
The structure of the ISS (exploded in this diagram) showing the various components and how they are assembled together. Credit: NASA
No additional modules or components were added until 2016 when Bigelow Aerospace installed their experimental Bigelow Expandable Activity Module (BEAM). All told, it took 13 years to construct the space station, an estimated $100 billion and required more than 100 rocket and Space Shuttle launches, and 160 spacewalks.
As of the penning of this article, the station has been continuously occupied for a period of 16 years and 74 days since the arrival of Expedition 1 on November 2nd, 2000. This is the longest continuous human presence in low Earth orbit, having surpassed Mir’s record of 9 years and 357 days.
Purpose and Aims:
The main purpose of the ISS is fourfold: conducting scientific research, furthering space exploration, facilitating education and outreach, and fostering international cooperation. These goals are backed by NASA, the Russian Federal Space Agency (Roscomos), the Japanese Aerospace Exploration Agency (JAXA), the Canadian Space Agency (CSA), and the European Space Agency (ESA), with additional support from other nations and institutions.
As far as scientific research goes, the ISS provides a unique environment to conduct experiments under microgravity conditions. Whereas crewed spacecraft provide a limited platform that is only deployed to space for a limited amount of time, the ISS allows for long-term studies that can last for years (or even decades).
Many different and continuous projects are being conducted aboard the ISS, which are made possible with the support of a full-time crew of six astronauts, and a continuity of visiting vehicles (which also allows for resupply and crew rotations). Scientists on Earth have access to their data and are able to communicate with the science teams through a number of channels.
The many fields of research conducted aboard the ISS include astrobiology, astronomy, human research, life sciences, physical sciences, space weather, and meteorology. In the case of space weather and meteorology, the ISS is in a unique position to study these phenomena because of its position in LEO. Here, it has a short orbital period, allowing it to witness weather across the entire globe many times in a single day.
It is also exposed to things like cosmic rays, solar wind, charged subatomic particles, and other phenomena that characterize a space environment. Medical research aboard the ISS is largely focused on the long-term effects of microgravity on living organisms – particularly its effects on bone density, muscle degeneration, and organ function – which is intrinsic to long-range space exploration missions.
The ISS also conducts research that is beneficial to space exploration systems. Its location in LEO also allows for the testing of spacecraft systems that are required for long-range missions. It also provides an environment where astronauts can gain vital experience in terms of operations, maintenance, and repair services – which are similarly crucial for long-term missions (such as missions to the Moon and Mars).
The ISS also provides opportunities for education thanks to participation in experiments, where students are able to design experiments and watch as ISS crews carry them out. ISS astronauts are also able to engage classrooms through video links, radio communications, email, and educational videos/web episodes. Various space agencies also maintain educational materials for download based on ISS experiments and operations.
Educational and cultural outreach also fall within the ISS’ mandate. These activities are conducted with the help and support of the participating federal space agencies and are designed to encourage education and career training in the STEM (Science, Technical, Engineering, Math) fields.
One of the best-known examples of this is the educational videos created by Chris Hadfield – the Canadian astronaut who served as the commander of Expedition 35 aboard the ISS – which chronicled the everyday activities of ISS astronauts. He also directed a great deal of attention to ISS activities thanks to his musical collaboration with the Barenaked Ladies and Wexford Gleeks – titled “I.S.S. (Is Somebody Singing)” (shown above).
His video, a cover of David Bowie’s “Space Oddity”, also earned him widespread acclaim. Along with drawing additional attention to the ISS and its crew operations, it was also a major feat since it was the only music video ever to be filmed in space!
Operations Aboard the ISS:
As noted, the ISS is facilitated by rotating crews and regular launches that transport supplies, experiments, and equipment to the station. These take the form of both crewed and uncrewed vehicles, depending on the nature of the mission. Crews are generally transported aboard Russian Progress spacecraft, which are launched via Soyuz rockets from the Baikonur Cosmodrome in Kazakhstan.
Roscosmos has conducted a total of 60 trips to the ISS using Progress spacecraft, while 40 separate launches were conducted using Soyuz rockets. Some 35 flights were also made to the station using the now-retired NASA Space Shuttles, which transported crew, experiments, and supplies. The ESA and JAXA have both conducted 5 cargo transfer missions, using the Automated Transfer Vehicle (ATV) and the H-II Transfer Vehicle (HTV), respectively.
In more recent years, private aerospace companies like SpaceX and Orbital ATK have been contracted to provide resupply missions to the ISS, which they have done using their Dragon and Cygnus spacecraft. Additional spacecraft, such as SpaceX’s Crew Dragon spacecraft, are expected to provide crew transportation in the future.
Alongside the development of reusable first-stage rockets, these efforts are being carried out in part to restore domestic launch capability to the US. Since 2014, tensions between the Russian Federation and the US have led to growing concerns over the future of Russian-American cooperation with programs like the ISS.
Crew activities consist of conducting experiments and research considered vital to space exploration. These activities are scheduled from 06:00 to 21:30 hours UTC (Universal Coordinated Time), with breaks being taken for breakfast, lunch, dinner, and regular crew conferences. Every crew member has their own quarters (which includes a tethered sleeping bag), two of which are located in the Zvezda Module and four more installed in Harmony.
During “night hours”, the windows are covered to give the impression of darkness. This is essential since the station experiences 16 sunrises and sunsets a day. Two exercise periods of 1 hour each are scheduled every day to ensure that the risks of muscle atrophy and bone loss are minimized. The exercise equipment includes two treadmills, the Advanced Resistive Exercise Device (ARED) for simulated weight training, and a stationary bicycle.
Hygiene is maintained thanks to water jets and soap dispensed from tubes, as well as wet wipes, rinseless shampoo, and edible toothpaste. Sanitation is provided by two space toilets – both of Russian design – aboard the Zvezda and Tranquility Modules. Similar to what was available aboard the Space Shuttle, astronauts fasten themselves to the toilet seat and the removal of waste is accomplished with a vacuum suction hole.
Liquid waste is transferred to the Water Recovery System, where it is converted back into drinking water (yes, astronauts drink their own urine, after a fashion!). Solid waste is collected in individual bags that are stored in an aluminum container, which are then transferred to the docked spacecraft for disposal.
Food aboard the station consists mainly of freeze-dried meals in vacuum-sealed plastic bags. Canned goods are available, but are limited due to their weight (which makes them more expensive to transport). Fresh fruit and vegetables are brought during resupply missions, and a large array of spices and condiments are used to ensure that food is flavorful – which is important since one of the effects of microgravity is a diminished sense of taste.
To prevent spillage, drinks and soups are contained in packets and consumed with a straw. Solid food is eaten with a knife and fork, which are attached to a tray with magnets to prevent them from floating away, while drinks are provided in dehydrated powder form and then mixed with water. Any food or crumbs that floats away must be collected to prevent them from clogging the air filters and other equipment.
Hazards:
Life aboard the station also carries with it a high degree of risk. These come in the form of radiation, the long-term effects of microgravity on the human physique, the psychological effects of being in space (i.e. stress and sleep disturbances), and the danger of collision with space debris.
In terms of radiation, objects within the Low-Earth Orbit environment are partially protected from solar radiation and cosmic rays by the Earth’s magnetosphere. However, without the protection of the Earth’s atmosphere, astronauts are still exposed to about 1 millisievert a day, which is the equivalent of what a person on Earth is exposed to during the course of a year.
As a result, astronauts are at higher risk for developing cancer, suffering DNA and chromosomal damage, and diminished immune system function. Hence why protective shielding and drugs are a must aboard the station, as well as protocols for limiting exposure. For instance, during solar flare activity, crews are able to seek shelter in the more heavily shielded Russian Orbital Segment of the station.
As already noted, the effects of microgravity also take a toll on muscle tissues and bone density. According to a 2001 study conducted by NASA’s Human Research Program (HRP) – which researched the effects on an astronaut Scott Kelly’s body after he spent a year aboard the ISS – bone density loss occurs at a rate of over 1% per month.
Similarly, a report by the Johnson Space Center – titled “Muscle Atrophy” – stated that astronauts experience up to a 20% loss of muscle mass on spaceflights lasting just five to 11 days. In addition, more recent studies have indicated that the long-term effects of being in space also include diminished organ function, decreased metabolism, and reduced eyesight.
Because of this, astronauts exercise regularly in order to minimize muscle and bone loss, and their nutritional regimen is designed to make sure they the appropriate nutrients to maintain proper organ function. Beyond that, the long-term health effects, and additional strategies to combat them, are still being investigated.
But perhaps the greatest hazard comes in the form of orbiting junk – aka. space debris. At present, there are over 500,000 pieces of debris that are being tracked by NASA and other agencies as they orbit the Earth. An estimated 20,000 of these are larger than a softball, while the remainder are about the size of a pebble. All told, there are likely to be many millions of pieces of debris in orbit, but most are so small they can’t be tracked.
These objects can travel at speeds of up to 28,163 km/h (17,500 mph), while the ISS orbits the Earth at a speed of 27,600 km/h (17,200 mph). As a result, a collision with one of these objects could be catastrophic to the ISS. The station is naturally shielded to withstand impacts from tiny bits of debris and well as micro-meteoroids – and this shielding is divided between the Russian Orbital Segment and the US Orbital Segment.
On the USOS, the shielding consists of a thin aluminum sheet that is held apart from the hull. This sheet causes objects to shatter into a cloud, thereby dispersing the kinetic energy of the impact before it reaches the main hull. On the ROS, shielding takes the form of a carbon plastic honeycomb screen, an aluminum honeycomb screen, and glass cloth, all of which are spaced over the hull.
The ROS’ shielding is less likely to be punctured, hence why the crew moves to the ROS whenever a more serious threat presents itself. But when faced with the possibility of an impact from a larger object that is being tracked, the station performs what is known as a Debris Avoidance Manoeuvre (DAM). In this event, the thrusters on the Russian Orbital Segment fire in order to alter the station’s orbital altitude, thus avoiding the debris.
Future of the ISS:
Given its reliance on international cooperation, there have been concerns in recent years – in response to growing tensions between Russia, the United States, and NATO – about the future of the International Space Station. However, for the time being, operations aboard the station are secure, thanks to commitments made by all of the major partners.
In January of 2014, the Obama Administration announced that it would be extending funding for the US portion of the station until 2024. Roscosmos has endorsed this extension but has also voiced approval for a plan that would use elements of the Russian Orbital Segment to construct a new Russian space station.
Known as the Orbital Piloted Assembly and Experiment Complex (OPSEK), the proposed station would serve as an assembly platform for crewed spacecraft traveling to the Moon, Mars, and the outer Solar System. There have also been tentative announcements made by Russian officials about a possible collaborative effort to build a future replacement for the ISS. However, NASA has yet to confirm these plans.
In April of 2015, the Canadian government approved a budget that included funding to ensure the CSA’s participation with the ISS through 2024. In December of 2015, JAXA and NASA announced their plans for a new cooperative framework for the International Space Station (ISS), which included Japan extending its participation until 2024. As of December 2016, the ESA has also committed to extending its mission to 2024.
The ISS represents one of the greatest collaborative and international efforts in history, not to mention one of the greatest scientific undertakings. In addition to providing a location for crucial scientific experiments that cannot be conducted here on Earth, it is also conducting research that will help humanity make its next great leaps in space – i.e. mission to Mars and beyond!
On top of all that, it has been a source of inspiration for countless millions who dream of going to space someday! Who knows what great undertakings the ISS will allow for before it is finally decommissioned – most likely decades from now?
All six members of the Expedition 50 crew aboard the International Space Station celebrated the holidays together with a festive meal on Christmas Day, Dec. 25, 2016 Image Credit: NASA
All six members of the Expedition 50 crew aboard the International Space Station celebrated the holidays together with a festive meal on Christmas Day, Dec. 25, 2016. Image Credit: NASA
As we celebrate the Christmas tidings of 2016 here on Earth, a lucky multinational crew of astronauts and cosmonauts celebrate the festive season floating in Zero-G while living and working together in space aboard the Earth orbiting International Space Station (ISS) complex – peacefully cooperating to benefit all humanity.
Today, Dec. 25, 2016, the six person Expedition 50 crew of five men and one woman marked the joyous holiday of Christ’s birth by gathering for a festive meal in space – as billions of Earthlings celebrated this Christmas season of giving, remembrance and peace to all here on our home planet.
This year is an especially noteworthy Space Christmas because it counts as Expedition 50. This is the 50th crew to reside on board since the space station began operating with permanent occupancy by rotating crews all the way back to 1998.
The Expedition 50 crew currently comprises of people from three nations supporting the ISS – namely the US, Russia and France; Commander Shane Kimbrough from NASA and flight engineers Andrey Borisenko (Roscosmos), Sergey Ryzhikov (Roscosmos), Thomas Pesquet (ESA), Peggy Whitson (NASA), and Oleg Novitskiy (Roscosmos).
Here a short video of holiday greetings from a trio of crew members explaining what Christmas in Space means to them:
Video Caption: Space Station Crew Celebrates the Holidays Aboard the Orbital Lab. Aboard the International Space Station, Expedition 50 Commander Shane Kimbrough and Peggy Whitson of NASA and Thomas Pesquet of the European Space Agency discussed their thoughts about being in space during the holidays and how they plan to celebrate Christmas and New Year’s in a downlink. Credit: NASA
“Hello from the Expedition 50 Crew! We’d like to share what Christmas means to us,” said Expedition 50 Commander Shane Kimbrough.
“For me it’s a lot about family,” said Expedition 50 Commander Shane Kimbrough. “We always travel to meet up with our family which is dispersed across the country. And we go home to Georgia and Florida … quite abit to meet up. Always a great time to get together and share with each other.”
“Although its typically thought of a season to get things, we in our family think about the giving aspect. Giving of our many talents and resources. Especially to those less fortunate.”
Kimbrough arrived on the complex in October, followed a month later by Whitson and Pesquet in November.
They were all launched aboard Russian Soyuz capsules from the Baikonur Cosmodrome in Kazakhstan.
Aboard the International Space Station, Expedition 50 Flight Engineer Peggy Whitson of NASA sent holiday greetings and festive imagery from the cupola on Dec. 18, 2016. Credit: NASA.
And Peggy Whitson especially has a lot to celebrate in space!
Because not only is Whitson currently enjoying her third long-duration flight aboard the station – as an Expedition 50 flight engineer. Soon she will become the first woman to command the station twice ! That momentous event happens when she assumes the role of Space Station Commander early in 2017 during the start of Expedition 51.
“In addition to family, there is another very important aspect to being on the ISS,” said Whitson.
“That is seeing the planet as a whole. It actually reinforces I think, that fact that we should live as one people and strive for peace.”
“I second the comments already made. I grew up in a family of 25 cousins,” said ESA’s Thomas Pesquet. “The only time we could catch up was around Christmas time…. So I always looked forward to that, although this year I can’t be with them of course … and will think of them.”
“I am making the most of this opportunity to look at the Earth. Reflect about what Christmas means to us as individuals and to the world in general. And we will have a good time on board the ISS and share a Christmas meal together.”
Aboard the International Space Station, Expedition 50 Flight Engineer Peggy Whitson of NASA sent holiday greetings and festive imagery from the Japanese Kibo laboratory module on Dec. 18, 2016. Credit: NASA
The crew is enjoying a light weekend of work and a day off tomorrow, Dec. 26.
After that they begin preparing for a pair of spacewalks in the new year by Kimbrough and Whitson – scheduled for Jan. 6 and 13. The crew is checking the spacesuits by testing the water among other activities.
The goal of the excursions is to “complete the replacement of old nickel-hydrogen batteries with new lithium-ion batteries on the station’s truss structure,” says NASA.
Research work also continues.
“Whitson, who is spending her second Christmas in space, and Pesquet drew blood, urine and saliva samples for the Fluid Shifts study. That experiment investigates the upward flow of body fluids in space potentially causing lasting vision changes in astronauts.”
NASA astronaut Peggy Whitson floats through the Unity module aboard the International Space Station. On her third long-duration flight aboard the station, Whitson will become the first woman to command the station twice when she assumes the role during Expedition 51. Credit: NASA
Among other activities, the crew is also unloading 4.5 tons of internal and external cargo, gear and fresh food – including six lithium-ion batteries – from Japan’s sixth H-II Transfer Vehicle (HTV-6), which recently arrived at the ISS on Dec 13.
A Cygnus cargo spacecraft named the SS Rick Husband is being prepared inside the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center for upcoming Orbital ATK CRS-6/OA-6 mission to deliver hardware and supplies to the International Space Station. Cygnus is scheduled to lift off atop a United Launch Alliance Atlas V rocket on March 22, 2016. Credit: Ken Kremer/kenkremer.com
SpaceX also hopes to resume Dragon cargo launches sometime in the new year after they resolve the issues that led to the destruction of a SpaceX Falcon 9 on Sept. 1 during fueling operations at pad 40 on the Cape.
Portrait of Giovanni Domenico Cassini, with the Paris Observatory in the background. Credit: Wikipedia Commons
During the Scientific Revolution, which took place between the 15th and 18th centuries, numerous inventions and discoveries were made that forever changed the way humanity viewed the Universe. And while this explosion in learning owed its existence to countless individuals, a few stand out as being especially worthy of praise and remembrance.
One such individual is Gionvanni Domenico Cassini, also known by his French name Jean-Dominique Cassini. An Italian astronomer, engineer, and astrologer, Cassini made many valuable contributions to modern science. However, it was his discovery of the gaps in Saturn’s rings and four of its largest moons for which he is most remembered, and the reason why the Cassini spacecraft bears his name.
Early Life and Education:
Giovanni Domenico Cassini was born on June 8th, 1625, in the small town of Perinaldo (near Nice, France) to Jacopo Cassini and Julia Crovesi. Educating by Jesuit scientists, he showed an aptitude for mathematics and astronomy from an early age. In 1648, he accepted a position at the observatory at Panzano, near Bologna, where he was employed by a rich amateur astronomer named Marquis Cornelio Malvasia.
During his time at the Panzano Observatory, Cassini was able to complete his education and went on to become the principal chair of astronomy at the University of Bologna by 1650. While there, he made several scientific contributions that would have a lasting mark.
La Meridiana, the meridian line calculated by Cassini while living in Bologna. Credit: Wikipedia Commons/Ilario/Cassinam
This included the calculation of an important meridian line, which runs along the left aisle of the San Petronio Basilica in Bologna. At 66.8 meters (219 ft) in length, it is one of the largest astronomical instruments in the worl and allowed for measurements that were (at the time) uniquely precise. This meridian also helped to settle the debate about whether or not the Universe was geocentric or heliocentric.
During his time in Italy, Cassini determined the obliquity of the Earth’s ecliptic – aka. it’s axial tilt, which he calculated to be 23° and 29′ at the time. He also studied the effects of refraction and the Solar parallax, worked on planetary theory, and observed the comets of 1664 and 1668.
In recognition of his engineering skills, Pope Clement IX employed Cassini with regard to fortifications, river management and flooding along the Po River in northern Italy. In 1663, Cassini was named superintendent of fortifications and oversaw the fortifying of Urbino. And in 1665, he was named the inspector for the town of Perugia in central Italy.
Paris Observatory:
In 1669, Cassini received an invitation by Louis XIV of France to move to Paris and help establish the Paris Observatory. Upon his arrival, he joined the newly-founded Academie Royale des Sciences (Royal Academy of Sciences), and became the first director of the Paris Observatory, which opened in 1671. He would remain the director of the observatory until his death in 1712.
An engraving of the Paris Observatory during Cassini’s time. Credit: Public Domain
In 1673, Cassini obtained his French citizenship and in the following year, he married Geneviève de Laistre, the daughter of the lieutenant general of the Comte de Clermont. During his time in France, Cassini spent the majority of his time dedicated to astronomical studies. Using a series of very long air telescopes, he made several discoveries and collaborated with Christiaan Huygens in many projects.
In the 1670s, Cassini began using the triangulation method to create a topographic map of France. It would not be completed until after his death (1789 or 1793), when it was published under the name Carte de Cassini. In addition to being the first topographical map of France, it was the first map to accurately measure longitude and latitude, and showed that the nation was smaller than previously thought.
In 1672, Cassini and his colleague Jean Richer made simultaneous observations of Mars (Cassini from Paris and Richer from French Guiana) and determined its distance to Earth through parallax. This enabled him to refine the dimensions of the Solar System and determine the value of the Astronomical Unit (AU) to within 7% accuracy. He and English astronomer Robert Hooke share credit for the discovery of the Great Red Spot on Jupiter (ca. 1665).
In 1683, Cassini presented an explanation for “zodiacal light” – the faint glow that extends away from the Sun in the ecliptic plane of the sky – which he correctly assumed to be caused by a cloud of small particles surrounding the Sun. He also viewed eight more comets before his death, which appeared in the night sky in 1672, 1677, 1698, 1699, 1702 (two), 1706 and 1707.
Illustration of Jupiter and the Galilean satellites. Credit: NASA
In ca. 1690, Cassini was the first to observe differential rotation within Jupiter’s atmosphere. He created improved tables for the positions of Jupiter’s Galilean moons, and discovered the periodic delays between the occultations of Jupiter’s moons and the times calculated. This would be used by Ole Roemer, his colleague at the Paris Observatory, to calculate the velocity of light in 1675.
In 1683, Cassini began the measurement of the arc of the meridian (longitude line) through Paris. From the results, he concluded that Earth is somewhat elongated. While in fact, the Earth is flattened at the poles, the revelation that Earth is not a perfect sphere was groundbreaking.
Cassini also observed and published his observations about the surface markings on Mars, which had been previously observed by Huygens but not published. He also determined the rotation periods of Mars and Jupiter, and his observations of the Moon led to the Cassini Laws, which provide a compact description of the motion of the Moon. These laws state that:
The Moon takes the same amount of time to rotate uniformly about its own axis asit takes to revolve around the Earth. As a consequence, the same face is always pointed towards Earth.
The Moon’s equator is tilted at a constant angle (about 1°32′ of arc) to the plane of the Earth’s orbit around the Sun (i.e. the ecliptic)
The point where the lunar orbit passes from south to north on the ecliptic (aka. the ascending node of the lunar orbit) always coincides with the point where the lunar equator passes from north to south on the ecliptic (the descending node of the lunar equator).
A collage of Saturn (bottom left) and some of its moons: Titan, Enceladus, Dione, Rhea and Helene. Credit: NASA/JPL/Space Science Institute
Thanks to his leadership, Giovanni Cassini was the first of four successive Paris Observatory directors that bore his name. This would include his son, Jaques Cassini (Cassini II, 1677-1756); his grandson César François Cassini (Cassini III, 1714-84); and his great grandson, Jean Dominique Cassini (Cassini IV, 1748-1845).
Observations of Saturn:
During his time in France, Cassini also made his famous discoveries of many of Saturn’s moons – Iapetus in 1671, Rhea in 167, and Tethys and Dione in 1684. Cassini named these moons Sidera Lodoicea (the stars of Louis), and correctly explained the anomalous variations in brightness to the presence of dark material on one hemisphere (now called Cassini Regio in his honor).
In 1675, Cassini discovered that Saturn’s rings are separated into two parts by a gap, which is now called the “Cassini Division” in his honor. He also theorized that the rings were composed of countless small particles, which was proven to be correct.
Death and Legacy:
After dedicating his life to astronomy and the Paris Observatory, Cassini went blind in 1711 and then died on September 14th, 1712, in Paris. And although he resisted many new theories and ideas that were proposed during his lifetime, his discoveries and contributions place him among the most important astronomers of the 17th and 18th centuries.
A comparison of the geocentric and heliocentric models of the universe. Credit: history.ucsb.edu
As a traditionalist, Cassini initially held the Earth to be the center of the Solar System. In time, he would come to accept the Solar Theory of Nicolaus Copernicus within limits, to the point that he accepted the model proposed by Tycho Brahe. However, he rejected the theory of Johannes Kepler that planets travel in ellipses and proposed hat their paths were certain curved ovals (i.e. Cassinians, or Ovals of Cassini)
Cassini also rejected Newton’s Theory of Gravity, after measurements he conducted which (wrongly) suggested that the Earth was elongated at its poles. After forty years of controversy, Newton’s theory was adopted after the measurements of the French Geodesic Mission (1736-1744) and the Lapponian Expedition in 1737, which showed that the Earth is actually flattened at the poles.
For his lifetime of work, Cassini has been honored in many ways by the astronomical community. Because of his observations of the Moon and Mars, features on their respective surfaces were named after him. Both the Moon and Mars have their own Cassini Crater, and Cassini Regio on Saturn’s moon Iapetus also bears his name.
Then there is Asteroid (24101) Cassini, which was discovered by C.W. Juels at in 1999 using the Fountain Hills Observatory telescope. Most recently, there was the joint NASA-ESA Cassini-Huygens missions which recently finished its mission to study Saturn and its moons. This robotic orbiter and lander mission was named in honor of the two astronomers who were chiefly responsible for discovering Saturn system of moons.
Artist’s impression of the Cassini space probe, part of the Cassini-Huygens mission to explore Saturn and its moons. Credit: NASA/JPL
In the end, Cassini’s passion for astronomy and his contributions to the sciences have ensured him a lasting place in the annals of history. In any discussion of the Scientific Revolution and of the influential thinkers who made it happen, his name appears alongside such luminaries as Copernicus, Galileo, and Newton.
The Millennium Tower luxury skyscraper in San Francisco is sinking and tilting. Image by MichaelTG - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=51657571
The Millennium Tower is a luxury skyscraper in San Francisco. It has been sinking and tilting since it’s construction 8 years ago. In fact, the 58 story building has sunk 8 inches, and tilted at least 2 inches. San Francisco is experiencing a building boom, and planners and politicians want to know why the Millennium Tower is having these problems.
Now they’re getting a little help from space.
The European Space Agency’s (ESA) Copernicus Sentinel-1 satellites have trained their radar on San Francisco. They’ve found that the Millennium Tower is sinking, or subsiding, at the alarming rate of almost 50 mm per year. Although the exact cause is not yet known for sure, it’s suspected that the building’s supporting piles are not resting on solid bedrock.
An artist’s illustration of the Sentinel-1. Image: ESA/ATG Medialab
The Sentinel-1 satellites are part of the ESA’s Copernicus Program. There are two of the satellites in operation, and two more are on the way. They employ Synthetic Aperture Radar to provide continuous imagery during the day, during the night, and through any kind of weather.
The satellites have several applications:
Monitoring sea ice in the arctic
Monitoring the arctic environment and other marine environments
Monitoring land surface motion
Mapping land surfaces, including forest, water, and soil
Mapping in support of humanitarian aid in crisis situations
Though the Sentinels were not specifically designed to monitor buildings, they’re actually pretty good at it. Buildings like the Millennium Tower are especially good at reflecting radar. When multiple passes are made with the satellites, they provide a very accurate measurement of ground subsidence.
Radar data from Sentinel-1 shows the displacement in San Francisco’s Bay Area. Yellow-red areas are sinking, while blue areas are rising. Green areas are not moving. Image: ESA SEOM INSARAP study / PPO.labs / Norut / NGU
The Millennium Tower is not the only thing in San Francisco Bay Area that Sentinel-1 can see moving. It’s also spotted movement in buildings along the Hayward Fault, an area prone to earthquakes, and the sinking of reclaimed land in San Rafael Bay. It’s also spotted some rising land near the city of Pleasanton. The recent replenishing of groundwater is thought to be the cause of the rising land.
Now other parts of the world, especially in Europe, are poised to benefit from Sentinel-1’s newfound prowess at reading the ground. In Oslo, Norway, the train station is built on reclaimed land. Newer buildings have proper foundations right on solid bedrock, but the older parts of the station are experiencing severe subsidence.
Sentinel-1 data shows that the Oslo train station, the red/yellow area in the center of the image, is sinking at the rate of 12-18mm per year. Image: Copernicus Sentinel data (2014–16) / ESA SEOM INSARAP study / InSAR Norway project / NGU / Norut / PPO.labs
John Dehls is from the Geological Survey of Norway. He had this to say about Sentinel: “Experience and knowledge gained within the ESA’s Scientific Exploitation of Operational Missions programme give us strong confidence that Sentinel-1 will be a highly versatile and reliable platform for operational deformation monitoring in Norway, and worldwide.”
As for the Millennium Tower in San Francisco, the problems continue. The developer of the building is blaming the problems on the construction of a new transit center for the city. But the agency in charge of that, the Transbay Joint Powers Authority, denies that they are at fault. They blame the developer’s poor structural design, saying that it’s not properly built on bedrock.
Now, the whole thing is before the courts. A $500 million class-action lawsuit has been filed on behalf of the residents, against the developer, the transit authority, and other parties.
It’s a good bet that data from the Sentinel satellites will be part of the evidence in that lawsuit.
Last week, ESA’s Schiaparelli lander smashed onto the surface of Mars. Apparently its descent thrusters shut off early, and instead of gently landing on the surface, it hit hard, going 300 km/h, creating a 15-meter crater on the surface of Mars.
Fortunately, the orbiter part of ExoMars mission made it safely to Mars, and will now start gathering data about the presence of methane in the Martian atmosphere. If everything goes well, this might give us compelling evidence there’s active life on Mars, right now.
It’s a shame that the lander portion of the mission crashed on the surface of Mars, but it’s certainly not surprising. In fact, so many spacecraft have gone to the galactic graveyard trying to reach Mars that normally rational scientists turn downright superstitious about the place. They call it the Mars Curse, or the Great Galactic Ghoul.
Mars eats spacecraft for breakfast. It’s not picky. It’ll eat orbiters, landers, even gentle and harmless flybys. Sometimes it kills them before they’ve even left Earth orbit.
NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft celebrated one Earth year in orbit around Mars on Sept. 21, 2015. MAVEN was launched to Mars on Nov. 18, 2013 from Cape Canaveral Air Force Station in Florida and successfully entered Mars’ orbit on Sept. 21, 2014. Credit: NASA
At the time I’m writing this article in late October, 2016, Earthlings have sent a total of 55 robotic missions to Mars. Did you realize we’ve tried to hurl that much computing metal towards the Red Planet? 11 flybys, 23 orbiters, 15 landers and 6 rovers.
How’s our average? Terrible. Of all these spacecraft, only 53% have arrived safe and sound at Mars, to carry out their scientific mission. Half of all missions have failed.
Let me give you a bunch of examples.
In the early 1960s, the Soviets tried to capture the space exploration high ground to send missions to Mars. They started with the Mars 1M probes. They tried launching two of them in 1960, but neither even made it to space. Another in 1962 was destroyed too.
They got close with Mars 1 in 1962, but it failed before it reached the planet, and Mars 2MV didn’t even leave the Earth’s orbit.
Five failures, one after the other, that must have been heartbreaking. Then the Americans took a crack at it with Mariner 3, but it didn’t get into the right trajectory to reach Mars.
Mariner IV encounter with Mars. Image credit: NASA/JPL
Finally, in 1964 the first attempt to reach Mars was successful with Mariner 4. We got a handful of blurry images from a brief flyby.
For the next decade, both the Soviets and Americans threw all kinds of hapless robots on a collision course with Mars, both orbiters and landers. There were a few successes, like Mariner 6 and 7, and Mariner 9 which went into orbit for the first time in 1971. But mostly, it was failure. The Soviets suffered 10 missions that either partially or fully failed. There were a couple of orbiters that made it safely to the Red Planet, but their lander payloads were destroyed. That sounds familiar.
Now, don’t feel too bad about the Soviets. While they were struggling to get to Mars, they were having wild success with their Venera program, orbiting and eventually landing on the surface of Venus. They even sent a few pictures back.
Finally, the Americans saw their greatest success in Mars exploration: the Viking Missions. Viking 1 and Viking 2 both consisted of an orbiter/lander combination, and both spacecraft were a complete success.
View of Mars from Viking 2 lander, September 1976. (NASA/JPL-Caltech)
Was the Mars Curse over? Not even a little bit. During the 1990s, the Russians lost a mission, the Japanese lost a mission, and the Americans lost 3, including the Mars Observer, Mars Climate Orbiter and the Mars Polar Lander.
There were some great successes, though, like the Mars Global Surveyor and the Mars Pathfinder. You know, the one with the Sojourner Rover that’s going to save Mark Watney?
The 2000s have been good. Every single American mission has been successful, including Spirit and Opportunity, Curiosity, the Mars Reconnaissance Orbiter, and others.
But the Mars Curse just won’t leave the Europeans alone. It consumed the Russian Fobos-Grunt mission, the Beagle 2 Lander, and now, poor Schiaparelli. Of the 20 missions to Mars sent by European countries, only 4 have had partial successes, with their orbiters surviving, while their landers or rovers were smashed.
Is there something to this curse? Is there a Galactic Ghoul at Mars waiting to consume any spacecraft that dare to venture in its direction?
ExoMars 2016 lifted off on a Proton-M rocket from Baikonur, Kazakhstan at 09:31 GMT on 14 March 2016. Copyright ESA–Stephane Corvaja, 2016
Flying to Mars is tricky business, and it starts with just getting off Earth. The escape velocity you need to get into low-Earth orbit is about 7.8 km/s. But if you want to go straight to Mars, you need to be going 11.3 km/s. Which means you might want a bigger rocket, more fuel, going faster, with more stages. It’s a more complicated and dangerous affair.
Your spacecraft needs to spend many months in interplanetary space, exposed to the solar winds and cosmic radiation.
Arriving at Mars is harder too. The atmosphere is very thin for aerobraking. If you’re looking to go into orbit, you need to get the trajectory exactly right or crash onto the planet or skip off and out into deep space.
And if you’re actually trying to land on Mars, it’s incredibly difficult. The atmosphere isn’t thin enough to use heatshields and parachutes like you can on Earth. And it’s too thick to let you just land with retro-rockets like they did on the Moon.
Landers need a combination of retro-rockets, parachutes, aerobraking and even airbags to make the landing. If any one of these systems fails, the spacecraft is destroyed, just like Schiaparelli.
If I was in charge of planning a human mission to Mars, I would never forget that half of all spacecraft ever sent to the Red Planet failed. The Galactic Ghoul has never tasted human flesh before. Let’s put off that first meal for as long as we can.
The last set of images taken by the Rosetta spacecraft's NAVCAM during the final month of its mission. ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0.
The Rosetta team has released the final batch of images taken by the NAVCAM during the last month of its two years of investigations at Comet 67P/Churyumov-Gerasimenko. It’s a big batch and they are absolutely stunning, but its sad to know they are the last NAVCAM images. The image set covers the period from September 2-30, 2016 when the spacecraft was on elliptical orbits that sometimes brought it to within 2 km of the comet’s surface, so you’ll see a wide variety of imagery with a variety of geology and lighting conditions.
Take a look below:
A large boulder sits precariously on Comet 67P/Churyumov-Gerasimenko as seem by Rosetta’s NAVCAM on September 11, 2016. Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0.
While these are the final NAVCAM images, there may be more images coming from the OSIRIS camera. Also, many other instruments will be releasing data, as they were active as long as possible before impact. Many of the science instruments were expected to return their last data from between 20 meters to 5 meters above the surface.
ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) collected data on the density of gas around the comet and its composition while GIADA (Grain Impact Analyser and Dust Accumulator) measured the dust density.
RPC’s (Rosetta Plasma Consortium) instrument suite provided a look at interaction between the solar wind and the surface of the comet. Alice, an Ultraviolet Imaging Spectrometer similar to the one on New Horizons, took high resolution ultraviolet spectra of the surface. RSI (Radio Science Investigation) got the most accurate measurements of the gravity field during descent.
A variety of geology and light on on Comet 67P/Churyumov-Gerasimenko as seem by Rosetta’s NAVCAM on September 5, 2016. Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0.
A field of bright bolders on Comet 67P/Churyumov-Gerasimenko as seem by Rosetta’s NAVCAM during September 2-20. Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0.
And here’s one of the last five images from Rosetta’s NAVCAM as it descended to its controlled impact on September 30 onto Comet 67P, taking incredible, close-up images during descent, this one just 18.1 km up. It shows the “drippy icing” landscape on this portion of the comet:
Single frame enhanced NavCam image taken on September 30, 2016 at 00:27 GMT, when Rosetta was 18.1 km from the center of the nucleus of Comet 67P/Churyumov-Gerasimenko. The scale at the surface is about 1.5 m/pixel and the image measures about 1.6 km across. ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0.
This artist's view shows the European Space Agency's Schiaparelli lander on Mars. It's unclear whether the landing was successful. Signals were received during its descent but then suddenly cut off. Mission control is working on the data now and will have an update on the status of the probe tomorrow morning Oct. 20. Credit: ESA/ATG medialab
This artist’s view shows the European Space Agency’s Schiaparelli lander on Mars. It’s unclear whether the landing was successful. Signals were received during its descent but then suddenly cut off. Mission control is working on the data now and will have an update on the status of the probe tomorrow morning Oct. 20. Credit: ESA/ATG medialab
Good news and bad news. First the good. After a seven-month and 300 million mile (483 million km) journey, the Trace Gas Orbiter (TGO) successfully achieved orbit around Mars today. A signal spike appeared out of the noise about 12:35 p.m. EDT to great applause and high-fives at ESA’s European Space Operations Center in Darmstadt, Germany.
Joy in the control room when the signal from the Trace Gas Orbiter was received this morning, signaling that the spacecraft had achieved orbit around Mars. Credit: ESA Livestream
Two hours later, news of the lander arrived. Not so good but to be fair, it’s still too early to tell. Schiaparelli broadcast a signal during its descent to the Red Planet that was received here on Earth and by the orbiting Mars Express. All well and good. But then mid-transmission, the signal cut out.
Paolo Ferri, head of ESA’s mission operations department, called the news “not good signs” but promised that his team would be analyzing the data through the night to determine the status of the lander. Their findings will be shared around mid-morning Friday Central European Time (around 5 a.m. EDT).
Three days ago, Schiaparelli separated from the orbiter and began a three-day coast to Mars. It entered the atmosphere today at an altitude of 76 miles (122 km) and speed of 13,049 mph (21,000 km/hr), protected from the hellish heat of re-entry by an aerodynamic heat shield.
Simulated sequence of the 15 images that the descent camera Schiaparelli module should have taken during its descent to Mars this morning. In the simulated images shown here, the first was made from 3 km up. The camera had planned to take images every 1.5 seconds with the final image in this at ~1.5 km. Depending on Schiaparelli’s actual descent speed, the final image may have been snapped closer to the surface. The views were generated from images taken by NASA’s Mars Reconnaissance Orbiter of the center of Schiaparelli’s landing ellipse, and represent the views expected at each altitude. Copyright spacecraft: ESA/ATG medialab; simulated views from NASA images (credit: NASA/JPL/MRO); landing ellipse background image: Mars Odyssey; simulation: ESA
If all went well, at 6.8 miles (11 km) altitude, it would have deployed its parachute and moments later, dropped the heat shield. At 0.7 miles (1.2 km) above the surface, the lander would have jettisoned the chute and rear protective cover and fired its nine retrorockets while plummeting to the surface at 155 mph (255 mph). 29 seconds later, the thrusters would have shut off with Schiaparelli dropping the remaining 6.5 feet (2 meters) to the ground. Total elapsed time: just under 6 minutes.
For now, have hope. Given that Schiaparelli was primarily a test of landing technologies for future Mars missions, whatever happened, everything we learn from this unexpected turn of events will be invaluable. You can continue to follow updates on ESA’s Livestream.
** Update Oct. 20: It appears that the thrusters on Schiaparelli may have cut out too soon, causing the lander to drop from a higher altitude. In addition, the ejection of the parachute and back heat shield may have happened earlier than expected.
This from ESA:
“The data have been partially analyzed and confirm that the entry and descent stages occurred as expected, with events diverging from what was expected after the ejection of the back heat shield and parachute. This ejection itself appears to have occurred earlier than expected, but analysis is not yet complete.
The thrusters were confirmed to have been briefly activated although it seems likely that they switched off sooner than expected, at an altitude that is still to be determined.”
Colour-coded topographic view of the Colles Nili region, showing the relative heights and depths of terrain. Credit: ESA/DLR/FU Berlin
In the northern hemisphere of Mars, between the planet’s southern highlands and the northern lowlands, is a hilly region known as Colles Nilli. This boundary-marker is a very prominent feature on Mars, as it is several kilometers in height and surrounded by the remains of ancient glaciers.
And thanks to the Mars Express mission, it now looks like this region is also home to some buried glaciers. Such was the conclusion after the orbiting spacecraft took images that revealed a series of eroded blocks along this boundary, which scientists have deduced are chunks of ice that became buried over time.
The Mars Express images show a plethora of these features along the north-south boundary. They also reveal several features that hint at the presence of buried ice and erosion – such as layered deposits as well as ridges and troughs. Similar features are also found in nearby impact craters. All of these are believed to have been caused by an ancient glacier as it retreated several hundred million years ago.
Artist’s impression of the Mars Express spacecraft in orbit. Credit: ESA/Medialab
It is further reasoned that these remaining ice deposits were covered by debris that was deposited from the plateau as it eroded. Wind-borne dust was also deposited over time, which is believed to be the result of volcanic activity. This latter source is evidenced by steaks of dark material deposited around the blocks, as well as dark sand dunes spotted within the impact craters.
Similar features are believed to exist within many boundary regions on Mars, and are believed to represent periods of glaciation that took place over the course of eons. And this is not the first time buried glaciers have been spotted on Mars.
For instance, back in 2008, the Mars Reconnaissance Orbiter (MRO) used its ground-penetrating radar to locate water ice under blankets or rocky debris, and at latitudes far lower than any that had been previously identified. At the time, this information shed light on a long-standing mystery about Mars, which was the presence of what are called “aprons”.
These gently-sloping rocky deposit, which are found at the bases of taller features, were first noticed by NASA’s Viking orbiters during the 1970s. A prevailing theory has been that these aprons are the result of rocky debris lubricated by small amounts of ice.
Artist’s impression of the separation of the ExoMars entry, descent and landing demonstrator module (Schiaparelli) from the Trace Gas Orbiter (TGO). Credit: ESA/ATG medialab
Combined with this latest info taken from the northern hemisphere, it would appear that there is plenty of ice deposits all across the surface of Mars. The presence (and prevalence) of these icy remnants offer insight into Mars’ geological past, which – like Earth – involved some “ice ages”.
The Mars Express mission has been actively surveying the surface of Mars since 2003. On October 19th, it will be playing a vital role as the Exomars mission inserts itself into Martian orbit and the Schiaparelli lander makes its descent and landing on the Martian surface.
Alongside the MRO and the ExoMars Orbiter, it will be monitoring signals from the lander to confirm its safe arrival, and will relay information sent from the surface during the course of its mission.
The ESA will be broadcasting this event live. And given that this mission will be the ESA’s first robotic lander to reach Mars, it should prove to be an exciting event!
ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Craggy hills meet dust-covered plains in this landscape on Comet 67P taken from 10 miles (16 km) up late Thursday evening during Rosetta’s free fall . The image measures 2,014 feet (614 meters) across or just under a half-mile. At typical walking speed, you could walk from one side to the other in 10 minutes. This and all the photos below are copyright ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Rosetta fell silent moments after 6:19 a.m. Eastern Time (12:19 UT) this morning, when it gently crashed into 67P/C-G 446 million miles (718 million km) from Earth. As the probe descended to the comet’s bouldery surface of the comet in free fall, it snapped a series of ever-more-detailed photographs while gathering the last bits data on the density and composition of cometary gases, surface temperature and gravity field before the final curtain was drawn.
Let’s take the trip down, shall we?
Rosetta’s last navigation camera image was taken just after the collision maneuver sequence Thursday evening (CDT) when the probe was 9.56 miles (15.4 km) above the comet’s surface. As in the photo above, much of the landscape is coated in a thick layer of dust that smoothes the comet’s contours.
As Rosetta continued its descent onto the Ma’at region on the small lobe of Comet 67P/Churyumov-Gerasimenko, the OSIRIS narrow-angle camera captured this photo from 3.6 miles (5.8 km) up. We see dust-covered terrains, exposed walls and a few boulders on Ma’at, not far from the target impact region, which is located just below the lower edge. The image measures 738 feet (225 meters) across.
Just a little bit lower now. This photo showing dramatic shadows was taken from 3.5 miles (5.7 km) above the surface of the comet at 4:21 a.m. EDT Friday morning September 30.
Headed for the abyss? This photo was made at 6:14 a.m. from 3/4 mile (1.2 km) high just a few minutes before impact. The scene measures just 108 feet (33 meters) wide.
This is Rosetta’s final image of Comet 67P/Churyumov-Gerasimenko, taken shortly before impact, an estimated 66 feet (~20 meters) above the surface. The view is similar to looking down from atop a three-story building. Side to side, the photo depicts an area only 7.8 feet (2.4 meters) across. The image is soft because Rosetta’s cameras weren’t designed to photograph the comet from this close.
Sad to see its signal fade. A sequence of screenshots taken at ESA’s ESOC mission control show the signal from Rosetta fading moments before impact. The peak of the spectrum analyser is strong at 6:19 EDT, and a few moments later, it’s gone. At impact, Rosetta’s was shut down and no further communication will or can be made with the spacecraft. It will continue to rest on the comet for well-nigh eternity until 67P vaporizes and crumbles apart. Credit: ESA
