The ESA has scheduled the launch of Cryosat-2 for February 25th aboard a Russian Dnepr rocket from the Baikonur Cosmodrome in Kazakhstan. This is the second attempt at launching the Earth-observing satellite that’s tasked with monitoring global ice thickness. The initial launch of Cryosat on October 8th, 2005 failed due to an anomaly of the launch sequence.
Other Earth-observing satellites have taken measurements of the ice thickness near the poles, but Cryosat-2 will be the first such satellite completely dedicated to monitoring ice thickness variations, and will keep tabs on the decline of sea ice, which in the Arctic has been shown to have shrunk 2.7% per decade since 1978.
Cryosat-2 will have a highly inclined polar orbit, and will reach 88 degrees north and south, so as to maximize the amount of observations of the Earth’s poles. The instruments aboard the satellite will be able to monitor the thickness changes in both sea ice and land ice with an accuracy of one centimeter. This will give scientists an unprecedented amount of data to work with to study how Arctic and Antarctic ice changes impact climate change, and vice versa.
The instrument aboard Cryosat-2 that will be measuring ice thickness is the SAR/Interferometric Radar Altimeter (SIRAL). This is a an altimeter and interferometer that operates in the Ku-band (13.575 GHz), and uses radar signals bounced off the ice to measure its thickness variations.
Cryosat-2 also has two other instruments to determine its position with a high amount of accuracy, the Doppler Orbit and Radio Positioning Integration by Satellite (DORIS) and Laser Retro-Reflector (LRR). DORIS detects and measures the Doppler shift of signals broadcast from a network of radio beacons spread around the world to give the velocity of the satellite relative to the Earth.
The LRR instrument will complement and help calibrate DORIS. The LRR is a small laser retroreflector that is attached to the underside of the satellite, and lasers from a network of tracking stations will be fired at the satellite. By measuring the interval between the firing of the laser and the return of the pulse, the position of the satellite can be measured very accurately.
The mission has a three-year lifespan, with a potential for a two-year extension. Cryosat-2 is currently nestled safely inside the Dnepr rocket’s protective fairing, and in the next nine days the satellite will be integrated into the rest of the launcher and moved out to the launch pad.
The new joint Mars exploration program of NASA and ESA is quickly pushing forward to implement an agreed upon framework to construct an ambitious new generation of red planet orbiters and landers starting with the 2016 and 2018 launch windows.
The European-led ExoMars Trace Gas Mission Orbiter (TGM) has been selected as the first spacecraft of the joint initiative and is set to launch in January 2016 aboard a NASA supplied Atlas 5 rocket for a 9 month cruise to Mars. The purpose is to study trace gases in the martian atmosphere, in particular the sources and concentration of methane which has significant biological implications. Variable amounts of methane have been detected by a martian orbiter and ground based telescopes on earth. The orbiter will likely be accompanied by a small static lander provided by ESA and dubbed the Entry, Descent and Landing Demonstrator Module (EDM).
The NASA Mars Program is shifting its science strategy to coincide with the new joint venture with ESA and also to build upon recent discoveries from the current international fleet of martian orbiters and surface explorers Spirit, Opportunity and Phoenix (see my earlier mars mosaics). Doug McCuiston, NASA’s director of Mars Exploration at NASA HQ told me in an interview that, “NASA is progressing quickly from ‘Follow the Water’ through assessing habitability and on to a theme of ‘Seeking the Signs of Life’. Looking directly for life is probably a needle in the haystack, but the signatures of past or present life may be more wide spread through organics, methane sources, etc”.
NASA and ESA will issue an “Announcement of Opportunity for the orbiter in January 2010” soliciting proposals for a suite of science instruments according to McCuiston. “The science instruments will be competitively selected. They are open to participation by US scientists who can also serve as the Principal Investigators (PI’s)”. Proposals are due in 3 months and will be jointly evaluated by NASA and ESA. Instrument selections are targeted for announcement in July 2010 and the entire cost of the NASA funded instruments is cost capped at $100 million.
“The 2016 mission must still be formally approved by NASA after a Preliminary Design Review, which will occur either in late 2010 or early 2011. Funding until then is covered in the Mars Program’s Next Decade wedge, where all new-start missions reside until approved, or not, by the Agency”, McCuiston told me. ESA’s Council of Ministers just gave the “green light” and formally approved an initial budget of 850 million euros ($1.2 Billion) to start implementing their ExoMars program for the 2016 and 2018 missions on 17 December at ESA Headquarters in Paris, France. Another 150 million euros will be requested within two years to complete the funding requirement for both missions.
ESA has had to repeatedly delay its own ExoMars spacecraft program since it was announced several years ago due to growing complexity, insufficient budgets and technical challenges resulting in a de-scoping of the science objectives and a reduction in weight of the landed science payload. The ExoMars rover was originally scheduled to launch in 2009 and is now set for 2018 as part of the new architecture.
The Trace Gas orbiter combines elements of ESA’s earlier proposed ExoMars orbiter and NASA’s proposed Mars Science Orbiter. As currently envisioned the spacecraft will have a mass of about 1100 kg and carry a roughly 115 kg science payload, the minimum deemed necessary to accomplish its goals. The instruments must be highly sensitive in order to be capable of detecting the identity and extremely low concentration of atmospheric trace gases, characterizing the spatial and temporal variation of methane and other important species, locating the source origin of the trace gases and determining if they are caused by biologic or geologic processes. Current photochemical models cannot explain the presence of methane in the martain atmosphere nor its rapid appearance and destruction in space, time or quantity.
Among the instruments planned are a trace gas detector and mapper, a thermal infrared imager and both a wide angle camera and a high resolution stereo color camera (1 – 2 meter resolution). “All the data will be jointly shared and will comply with NASA’s policies on fully open access and posting into the Planetary Data System”, said McCuiston.
Another key objective of the orbiter will be to establish a data relay capability for all surface missions up to 2022, starting with 2016 lander and two rovers slotted for 2018. This timeframe could potentially coincide with Mars Sample Return missions, a long sought goal of many scientists.
If the budget allows, ESA plans to piggyback a small companion lander (EDM) which would test critical technologies for future missions. McCuiston informed me that, “The objective of this ESA Technology Demonstrator is validating the ability to land moderate payloads, so the landing site selection will not be science-driven. So expect something like Meridiani or Gusev—large, flat and safe. NASA will assist ESA engineering as requested, and within ITAR constraints.” EDM will use parachutes, radar and clusters of pulsing liquid propulsion thrusters to land.
“ESA plans a competitive call for instruments on their 3-4 kg payload”, McCuiston explained. “The Announcement of Opportunity will be open to US proposers as well so there may be some US PI’s. ESA wants a camera to ‘prove’ they got to the ground. Otherwise there is no significant role planned for NASA in the EDM”.
The lander would likely function as a weather station and be relatively short lived, perhaps 8 Sols or martian days, depending on the capacity of the batteries. ESA is not including a long term power source, such as from solar arrays, so the surface science will thus be limited in duration.
The orbiter and lander would separate upon arrival at Mars. The orbiter will use a series of aerobraking maneuvers to eventually settle into a 400 km high circular science orbit inclined at about 74 degrees.
The joint Mars architecture was formally agreed upon last summer at a bilateral meeting between Ed Weiler (NASA) and David Southwood (ESA) in Plymouth, UK. Weiler is NASA’s Associate Administrator for the Science Mission Directorate and Southwood is ESA’s Director of Science and Robotic Exploration. They signed an agreement creating the Mars Exploration Joint Initiative (MEJI) which essentially weds the Mars programs of NASA and ESA and delineates their respective program responsibilities and goals.
“The key to moving forward on Mars exploration is international collaboration with Europe”, Weiler said to me in an interview. “We don’t have enough money to do these missions separately. The easy things have been done and the new ones are more complex and expensive. Cost overruns on Mars Science Lab (MSL) have created budgetary problems for future mars missions”. To pay for the MSL overrun, funds have to be taken from future mars budget allocations from fiscal years 2010 to 2014.
“2016 is a logical starting point to work together. NASA can have a 2016 mission if we work with Europe but not if we work alone. We can do so much more by working together since we both have the same objectives scientifically and want to carry out the same types of mission”. Weiler and Southwood instructed their respective science teams to meet and lay out a realistic and scientifically justifiable approach. Weiler explained to me that his goal and hope was to reinstate an exciting Mars architecture with new spacecraft launching at every opportunity which occurs every 26 months and which advance the state of the art for science. “It’s very important to demonstrate a critical new technology on each succeeding mission”.
More on the 2018 mission plan and beyond in a follow up report.
NASA and the European Space Agency (ESA) have officially agreed to combine their efforts in the exploration and study of Mars. The heads of both agencies, NASA administrator Charles Boden and ESA director-general Jean-Jacques Dordain signed an agreement that officially binds the two agencies together for upcoming orbiter and rover missions. Discussions of this cooperation began in December of 2008, and culminated in a meeting in June 2009, out of which came the official agreement signed last week.
The new “letter of intent” outlines the Mars Exploration Joint Initiative (MEJI), under which mission engineers will cooperate in the design and launch of rovers, orbiters and landers into the 2020s, with the ultimate goal of returning rocks from Mars to Earth for study. The first collaborative mission is a European-led orbiter that will also place a meteorological station on Mars planned for 2016. This will be followed by surface rovers to keep Spirit and Opportunity company (c’mon, you know they’ll still be ticking!) in 2018, and possibly a network of landers shortly after in 2018, one of which will include the ESA’s ExoMars Lander.
NASA will take care of the launching rockets for 2016 and 2018, and the ESA will cover the entry, descent and landing for the first mission in 2016.
The signing of this document makes official the talks held in Plymouth, UK this past June. Since the talks, most of the fine print has been worked out on the collaboration – this signing just seals the deal.
The ESA and NASA, both under financial constraints in their Mars exploration programs, envision this new union to allow both to to launch vehicles in the window that opens every 26 months for missions to Mars. NASA’s most recently planned mission to the Red Planet, the Mars Science Laboratory, missed the October 2009 window because of technical problems, so will have to be launched in 2011 instead. The same fate befell the ESA ExoMars lander, which has been postponed three times – until 2018 – from the initial launch date of 2009. This joint initiative aims at preventing such delays by sharing both engineering and financial responsibilities.
NASA’s associate administrator for science, Dr Ed Weiler, told the BBC back in July,”We have very similar scientific goals, maybe we ought to consider working together jointly on all our future Mars missions, so that we can do more than either one of us can do by ourselves.”
Hopefully, this collaboration will provide both administrations with the opportunity to get more science done for cheaper, and extend further the already amazing capabilities of proposed missions to the Red Planet.
The comet chasing spacecraft Rosetta will make its third and final swing by the Earth on November 13th to pick up more speed for the last part of a 10-year journey that lies ahead. Its mission is to place a lander on comet 67P/Churyumov-Gerasimenko and chase the comet for an entire year on its orbit around the Sun. The spacecraft will be visible to observers from the ground in certain locations on the Earth. This last flyby will increase the spacecraft’s speed by 3.6 km/s (2.2 miles/s) with respect to the Sun, giving Rosetta the energy it needs to boost it to the outer regions of the Solar System.
Rosetta was launched March 2nd, 2004, and will visit a host of targets on its way to comet 67P/Churyumov-Gerasimenko. Rosetta already paid a visit to asteroid 2867 Steins in September 2008. It will visit comet 21 Lutetia 10 June 2010, after which it will go into hibernation until it reaches its final destination in May 2014.
Once Rosetta arrives at 67P/Churyumov-Gerasimenko, it will deploy its Philae lander on the comet’s nucleus, and continue to orbit and study the comet for an entire year during its closest orbit of the Sun. This is the first mission ever to orbit and land on a comet, and promises to return a wealth of data on cometary interaction with the Sun. Comets also contain mostly undisturbed materials from the formation of the Solar System in their nuclei, so studying their composition gives scientists an look into how our Solar System developed.
During the flyby of Earth in November of 2007, Rosetta took the breathtaking image of the Earth pictured here. This next flyby will give observers on the ground a chance to take a look back at Rosetta. The closest approach will occur on November 13th at 8:45 Central European Time (07:45 UT).
Unfortunately, the spacecraft will only be visible from parts of Europe, South America and Africa, as can be seen in the image below. If you are in these regions during the approach, and have favorable conditions, there is a wealth of observing information on the Rosetta blog, specifically on the posts Tips for Sky Junkies I and Tips for Sky Junkies II. They will also be closely following the flyby on the blog, so you can check there for updates on the eve of the event if you are outside the observable range of the spacecraft.
As always, you can check back with us on Universe Today for more coverage of Rosetta’s journey!
UPDATE: Information about both SMOS and the Proba-2 satelite are on ESA Television. The program loop is embedded at the bottom of this post. Enjoy!
Last night at 2:50 am Central European Time, two European Space Agency (ESA) satellites were successfully launched from the Plesetsk Cosmodrome in Northern Russia. The Rockot launch vehicle was carrying both the Soil Moisture and Ocean Salinity (SMOS) satellite, and the Proba-2 satellite. SMOS will monitor the moisture exchange of the Earth between the ocean, air and land as well as the salinity of the oceans and the moisture of the soil in an effort to better understand how these factors influence the climate of our planet. Proba-2 will test out various instruments, including a small wide angle optical camera, and instruments for monitoring the plasma environment in orbit and the Sun’s corona.
SMOS is part of the ESA’s Earth Observation Envelope Program, an initiative to study in scientific detail from space the ongoing changes of the Earth. The GOCE satellite launched earlier this year to study the Earth’s gravity field and ocean circulation is another part of this program.
SMOS is the first satellite designed with the intent of measuring ocean salinity from space. To do this, it will implement a multi-part microwave antenna to monitor the oceans at a wavelength of about 23cm. At this frequency, an antenna of 5-10 meters (15-30 feet) is needed to make the measurements. This is too large to fit into a standard rocket payload bay, so the mission engineers employed what is called ‘synthetic aperture synthesis’. This is a technique used in radio astronomy that strings together separate antennae in different places, allowing the antennae to act as one larger antenna. A perfect example of this is the Very Large Array in New Mexico. The SMOS antenna has three foldable arms that are 3 meters (6 feet) long apiece, and extend to form a Y shape. Along the arms are 69 small antennae that all act together to take measurements as if they were one larger antenna.
Volker Liebig, ESA’s Director of Earth Observation Programs said in an ESA press release:
“The data collected by SMOS will complement measurements already performed on the ground and at sea to monitor water exchanges on a global scale. Since these exchanges – most of which occur in remote areas – directly affect the weather, they are of paramount importance to meteorologists. Moreover, salinity is one of the drivers for the Thermohaline Circulation, the large network of currents that steers heat exchanges within the oceans on a global scale, and its survey has long been awaited by climatologists who try to predict the long-term effects of today’s climate change.”
The other satellite piggybacking on the SMOS mission launch is the suitcase-sized Proba-2, part of a series of missions in the ESA’s General Support Technology Program to test out new technology in space for further development on other ESA missions. Proba-2 is carrying a digital sun sensor, a high-precision magnetometer, and dual frequency GPS space receiver among other instruments for a Belgian study of solar physics and Czech study of plasma physics.
Both satellites arrived in their sun-synchronous orbits, and initial systems checks indicate that both are operating as expected. SMOS will orbit at 760 km (472 miles) above the Earth, and Proba-2 at 725 km (450 miles). SMOS, once calibrated, will reach full operational status in about six months, and Proba-2 will become fully operation in two months.
From the “this makes complete sense” department: NASA and ESA have established an initiative to make future explorations of Mars a joint venture. The ESA Director of Science and Robotic Exploration, David Southwood, met with NASA’s Associate Administrator for Science, Ed Weiler at the end of June and created the Mars Exploration Joint Initiative (MEJI) that will provide a framework for the two agencies to define and implement their scientific, programmatic and technological goals at Mars. The initiative includes launch opportunities in 2016, 2018 and 2020, with landers and orbiters conducting astrobiological, geological, geophysical and other high-priority investigations, leading up to a sample return mission in the 2020s.
Both NASA and ESA have been reassessing their Mars exploration programs, and Weiller revealed at a press conference last year (when it was announced that the Mars Science Laboratory would be delayed) that NASA and ESA would seek to work together. But now it is official.
The two space agencies will be working together to plan future missions. A joint architecture review team will be established to assist the agencies in planning the mission portfolios. As plans develop, they will be reviewed by ESA member states for approval and by the US National Academy of Sciences.
Making good on its promise to work together with other space agencies, NASA has selected two science instruments that will fly on board European Space Agency (ESA) spacecraft, one heading to Mars on the ExoMars rover, the other to Mercury with the BepiColombo orbiter. “The selections will further advance our knowledge of these exciting terrestrial planets,” said Jim Green, director of NASA’s Planetary Division at NASA Headquarters in Washington. “The international collaboration will create a new chapter in planetary science and provide a strong partnership with the international science community to complement future robotic and human exploration activities.”
The Lander Radio-Science on ExoMars, or LaRa, will use NASA’s Deep Space Network of radio telescopes to track part of ESA’s ExoMars mission. Scheduled to launch in 2016, the mission consists of a fixed lander and a rover that will roam Mars collecting soil samples for detailed analysis.
Data relayed from the lander back to the network will allow scientists to measure and analyze variations in the length of the day and location of the planet’s rotational axis. This data will help researchers further dissect the structure of the Red Planet’s interior, including the size of its core. When combined with the lander’s onboard instruments, the data also may help confirm whether the planet’s interior is still, at least partially, composed of liquid. William Folkner of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., is the principal investigator. The project costs approximately $6.6 million.
The second science instrument selection, named Strofio, will employ a unique mass spectrometer on board the BepiColombo mission. The instrument will determine the mass of atoms and molecules to reveal the composition of Mercury’s atmosphere. The investigation will study the atmosphere, which is formed from material ejected from its surface, to reveal the composition of Mercury’s surface.
Strofio will be a component of the Italian Space Agency’s suite of science instruments that will fly aboard BepiColombo . Scheduled for launch in 2013, the mission is composed of two spacecraft. Japan will build one spacecraft to study the planet’s magnetic field. ESA will build the other to study Mercury directly. Stefano Livi of the Southwest Research Institute in San Antonio is the principal investigator. The project costs approximately $31.8 million.
The selections were chosen from eight proposals submitted in December 2008 in response to NASA’s new Stand Alone Mission of Opportunity, known as Salmon. NASA solicited proposals for investigations that address planetary science research objectives on non-agency missions. A key criterion is that science goals, including data archiving and analysis, must be accomplished for less than $35 million.
Image credit: ESA
For the first time, the ‘videometer’ (VDM), a new technology device to ensure very precise automatic rendezvous operations between the 20.7 tonne Jules Verne Automated Transfer Vehicle and the ISS, has been successfully tested this month.
State of the art
Based on the design of a star tracker, the Jules Verne videometer, which is the first automatic optical operational system ever used for spacecraft navigation, has been through extensive simulated rendezvous tests. This state of the art rendezvous technology is the crucial part of the new European cargo spaceship to which it gives its specific name of Automated Transfer Vehicle (ATV).
“For the first time, the ATV rendezvous sensors were used successfully in real conditions. And, within their operational domain, they worked exceptionally well,” said ESA ATV engineer Stein E. Strandmoe, who supervised a critical 10-day test campaign.
For the final rendezvous manoeuvres, the ATV will use its videometer eye-like sensors, combined with additional parallel measurement systems, which allow an automatic docking with an incredible centimetre precision while the spacecraft and the ISS are circling the Earth at 28 000 km/h. “The first European rendezvous spacecraft is expected to dock with ISS next year with the accuracy of the size of a one Euro coin”, said ESA astronaut Jean-Fran?ois Clervoy, senior advisor to the ATV programme.
These built-in automatic capabilities of the ATV must be compatible with the demanding requirements of human spaceflight safety, necessary for the permanently crewed ISS.
The videometer is able to analyse images of its emitted laser beam automatically reflected by passive retroreflectors serving as targets installed on the Station, next to the Russian docking port where the ATV will be attached.
During the last 200 metres of the orbital final approach manoeuvre, the videometer must automatically recognize the retroreflectors target patterns and then calculate the distance and direction to the docking port.
This precise tracking of the relative motion between the two spacecraft as they get closer ? starting at a speed of up to 3.6 km/h ? provides indispensable information to the on-board Guidance, Navigation and Control (GNC) system, which automatically pilots the bus-sized cylindrical ESA cargo ship towards the ISS.
To realistically check the videometer capabilities ? in targeting and acquisition ? the tests were conducted in a hi-tech ship hull research facility at the French defence agency ‘D?l?gation G?n?rale pour l’Armement’ (DGA), located in Val-de-Reuil, 100 km west of Paris. A contract between ESA and DGA will allow further ATV rendezvous testing, including during the Jules Verne flight, if needed.
Inside an exceptional building, 600 metres in length, a 120 000 kg mobile platform, able to ride on 550 metre long rails, enabled the simulation of a continuous approach between the two space vehicles from a range of several hundred metres to within almost docking distance. On the platform, a set of passive rendezvous targets (retroreflectors), identical to the ones to be installed on ISS, were facing the videometer which was mounted on an articulated robotic arm (with six degrees of freedom) representing the ATV motion.
This seven metre high mobile arm was used to simulate the angular movements of the ATV to check if the videometer was still able to target the ISS retroreflectors and provide the information to the ATV control system necessary to adjust its trajectory accordingly.
First time success
The results of the test campaign showed that the whole videometer system ? that is to say the laser illuminator and the image analyser of the reflected laser beams ? was able to continuously track the simulated ISS platform from a distance of 313 metres, right up close to docking. “We have stable acquisition and tracking in its entire operating domain,” said Stein Strandmoe. At greater distances, Jules Verne will use a relative GPS reference system to get closer to the Station.
“The most surprising thing was that the sensors were almost undisturbed when we tried to fool them with other reflecting surfaces or other lights that could interfere with rendezvous targets in the ISS background,” said Strandmoe. “It’s amazing how the videometer, as a totally new development, proved to be such a robust system. I was quite surprised that it worked so well the first time it was tested!”