OrbitalHub

Credits: NASA

In 2002, an instrument on the Mars Odyssey spacecraft detected hydrogen under the Martian surface. This was regarded as clear evidence that there is subsurface water ice on Mars.

In 2003, NASA decided to revive a mission that was cancelled in 2001 due to the fact that a previous mission, the Mars Polar Lander, was lost in 1999. The revived mission was named Phoenix.

A Lander that could reach out and touch the ice was needed. The half-built spacecraft for the previously cancelled mission already had in place a 7.7-foot robotic arm that could do the trick.

A JPL team reviewed the data from the failed mission in 1999 and corrected the mistakes made. Every system used in the previous design was taken apart, tested, and examined. The suspected culprits were the retrorockets used during landing. More than a dozen issues that could have caused a failure of the new planned mission were found and fixed.

Credits: NASA / JPL

The Phoenix mission inherited a capable spacecraft partially built for the Mars Surveyor Program 2001. As we mentioned, the lessons learned from the Mars Polar Lander helped improve the existing systems. As for any other space mission, the conditions in which the spacecraft operates dictate the design.

In the case of the Phoenix mission, the following phases were considered: the launch, the cruise, the atmospheric entry, the touchdown, and the surface operations phase. The launch induces tremendous load forces and vibrations. The 10-month cruise to Mars exposes the spacecraft to the vacuum of space, solar radiation, and possible impacts with micrometeorites. During the atmospheric entry, the spacecraft is heated to thousands of degrees due to aero braking, and has to withstand tremendous deceleration during the parachute deployment. The extremely cold temperatures of the Martian arctic and the dust storms must be considered during the surface operations phase.

Credits: NASA / JPL

Several instruments are mounted on the Lander: the robotic arm (RA), the robotic arm camera (RAC), the thermal and evolved gas analyzer (TEGA), the Mars descent imager (MARDI), the meteorological station (MET), the surface stereo imager (SSI), and the microscopy, electrochemistry, and conductivity analyzer (MECA).

The RA was built by the Jet Propulsion Laboratory and was designed to perform the scouting operations on Mars, such as digging trenches and scooping the soil and water ice samples. RA delivered the samples to the TEGA and the MECA. RA is 2.35 meters long, it has an elbow joint in the middle, and it is capable of digging trenches 0.5 meters deep in the Martian soil.

The University of Arizona and the Max Planck Institute in Germany built the RAC. The camera is attached to the RA, just above the scoop placed at the end of the arm. RAC provided close-up, full-color images.

Credits: NASA / JPL

TEGA was developed by the University of Arizona and University of Texas, Dallas. TEGA used eight tiny ovens to analyze eight unique ice and soil samples. By employing a process called scanning calorimetry, and by using a mass spectrometer to analyze the gas obtained in the furnaces as the temperature raised to 1000 degrees Celsius, TEGA determined the ratio of various isotopes of hydrogen, oxygen, carbon, and nitrogen.

MARDI was built by Malin Space Science Systems. From what I could gather, the MARDI was not used by the Lander due to some integration issues.

The Canadian Space Agency (YAY Canada!) was responsible for the overall development of the meteorological station (MET). Two companies from Ontario, MD Robotics and Optech Inc., provided the instruments for the station.

The SSI served as the eyes of the Phoenix mission. SSI provided high-resolution, stereo, panoramic images of the Martian arctic. An extended mast holds the SSI, so the images were recorded from two meters above the ground.

Credits: NASA / JPL

MECA was built by the Jet Propulsion Laboratory. The instrument was used to characterize the soil by dissolving small amounts of soil in water. MECA determined the pH, the mineral composition, as well as the concentration of dissolved oxygen and carbon dioxide in the soil samples that were collected.

We would like to highlight some of the important moments during the mission:

August 4, 2007 – Delta II rocket launch from Cape Canaveral. The three-stage Delta II rocket with nine solid rocket boosters lifted off from Cape Canaveral, carrying the Phoenix spacecraft on the first leg of its journey to Mars.

Credits: NASA / JPL -Caltech / University of Arizona

May 25, 2008 – Phoenix Mars Lander touchdown. The Phoenix entered the Martian atmosphere at 13,000 mph. It took 7 minutes for the Lander to slow down with the aid of a parachute and to land using its retrorockets. The mission team did not have to wait long before discovering ice because the blasts from the retrorockets had blown away the topsoil during landing and revealed ice patches under the lander.

November 2, 2008 – Last signal received from the Lander. On this date, communication was established for the last time with Phoenix. Due to the latitude of the landing site, not enough sunlight is available and the solar arrays are unable to collect the power necessary to charge the batteries that operate the instruments mounted on the Lander. At the landing site, the weather conditions are worsening.

November 10, 2008 – Mission declared completed. NASA declares that the Mars Phoenix Lander has completed a successful mission on the Red Planet. Phoenix Mars Lander has ceased communications after being operational for more than five months (the designed operational life of the mission was 90 days).

November 13, 2008 – Mission Honored. NASA’s Phoenix Mars Lander was awarded Best of What’s New Grand Award in the aviation and space category by Popular Science magazine.

Credits: NASA / JPL

The Mars Phoenix Lander made significant contributions to the study of the Red Planet. Phoenix verified the presence of water ice under the Martian surface, and it returned thousands of pictures from Mars. Phoenix also found small concentrations of salts that could be nutrients for life, it discovered perchlorate salt, and calcium carbonate, which is a marker of effects of liquid water.

Phoenix provided a mission long weather record, with data on temperature, pressure, humidity, and wind, as well as observations on snow, haze, clouds, frost, and whirlwinds.

Principal Investigator Peter H. Smith of the University of Arizona led the Phoenix mission. The project management was done at NASA’s Jet Propulsion Laboratory and the development at Lockheed Martin Space Systems in Denver. Other contributors were the Canadian Space Agency, the University of Neuchatel (Switzerland), the University of Copenhagen (Denmark), the Max Planck Institute (Germany), and the Finnish Meteorological Institute.

For more information about the Phoenix mission, check out the NASA Phoenix Mars Lander Page.

Credits: ESA – S. Corvaja 2007

CNES and ESA signed the development contract to build the launch facilities for Soyuz at the Guiana Space Centre on July 19, 2005. The Soyuz launcher will give Europe medium-lift capability and will complete the range of launchers operated by Arianespace, which includes the Ariane 5 heavy-lift launcher and the Vega small launcher.

The Soyuz launchers that will liftoff from Kourou have a number of improvements: an updated digital flight control system, an increased-performance third stage, and the larger Soyuz ST payload fairing.

The launcher has a length of 46.2 meters, a diameter of 10.3 meters, and a liftoff mass of 308 tons. Due to the position of the launch site, close to the equator, the payload capacity of the launcher has increased significantly: 3,150 kg to a geostationary orbit, and 4,900 kg to a sun-synchronous orbit, with a circular altitude of 820 km.

Soyuz is a reliable, four-stage launch vehicle, which has been in production since 1957 and has accounted for more than 1,700 missions to date.

The first stage is composed of the four boosters that are assembled around the central core of the launcher. The RD-107A engines installed on the boosters use liquid oxygen and kerosene as propellant combination. Each engine has four combustion chambers and four nozzles. One aerofin and two movable vernier thrusters per engine are used for the three-axis flight control.

Credits: ESA – S. Corvaja 2008

The second stage consists of the central core surrounded by the boosters. It uses the same propellant combination for powering the RD-108A engine with four combustion chambers and nozzles.

Four vernier thrusters are used for three-axis flight control, after the boosters of the first stage are jettisoned during flight.

The engines of the first two stages are ignited 20 seconds before liftoff. The reason for this is that the launch procedures include monitoring the engine health parameters just before liftoff, while the engines are operating at an intermediate level of thrust. This reminds me of the SpaceX Falcon 1 booster launch procedures. SpaceX engineers perform a similar monitoring procedure for the Merlin engine just before the Falcon 1 liftoff.

The third stage utilizes a RD-0124 engine, also powered by liquid oxygen and kerosene. The liquid oxygen and kerosene tanks are pressurized using helium stored in vessels located in the liquid oxygen tank. The avionics module of the launcher is carried by this stage. The new flight control system improves the accuracy and the control capability for the launcher, as additional flight control authority is needed for the enlarged payload fairing.

Credits: ESA – S. Corvaja 2008

The upper stage of the Soyuz launcher is called Fregat. Fregat is an autonomous and flexible upper stage with its own guidance, navigation, control, tracking, and telemetry systems. It was designed to operate as an orbital vehicle, and it extends the launch capabilities of the Soyuz launcher to medium-Earth orbits, Sun-synchronous orbits, geostationary transfer orbits, and Earth escape trajectories.

The Fregat stage can be restarted up to 20 times in flight, it can provide three-axis stabilization, and perform a spin-up of the spacecraft payload. Fregat uses a bi-propellant propulsion system: UDMH (unsymmetrical dimethylhydrazine) and NTO (nitrogen tetroxide).

The payload fairing is the most visible change to the Soyuz launcher. The new Soyuz fairing has a diameter of 4.11 meters and a length of 11.4 meters. The fairing is based on the configuration used for Ariane 4 vehicles.

The construction of the Soyuz launch base in French Guiana started in early 2007. At the groundbreaking ceremony on February 26, 2007, a number of European space industry officials were present: Jean-Jacques Dordain – ESA Director General, Yannick d’Escatha – President of CNES, Jean-Yves Le Gall – Director General of Arianespace, and Anatoly Perminov – Head of Roscosmos.

In 2007, Arianespace ordered four Soyuz launchers for the early launch missions that are scheduled for the second half of 2009. A contract was also signed in September 2008 for 10 more Soyuz launch vehicles.

The Soyuz launch missions that are scheduled for 2009 signal the beginning of a new chapter in ESA-Russian relations. Stay tuned for more information about the Soyuz launches from French Guiana!

Credits: ESA – J. Huart

The small-payload market is rapidly expanding. Institutional programs (mostly Earth observation and scientific missions) drive this emerging market. In order to meet the demands of the small-payload market, ESA has transformed the small launcher program initiated by the Italian Space Agency (ASI) in the 1990s into Vega, a co-operative project with other Member States within the ESA framework.

The small-payload market consists of satellites up to 3,000 kg and it stands at around five missions per year. There are many classifications for the satellites in this market, so we will present just one classification for informational purposes. The satellites in this class are divided into three categories: micro-satellites (up to 300 kg), mini-satellites (from 300 kg to 1,000 kg), and small satellites (from 1,000 kg to 3,000 kg).

The orbits required for the deployment of these satellites are mainly Sun Synchronous Orbits (SSO) and Low Earth Orbits (LEO). Vega’s in-orbit launch capability benchmark is 1,500 kg into a 700 km altitude polar orbit. Being designed to cope with a wide range of missions, Vega will address the various market requirements for this class of satellites.

Credits: ESA

Vega is a single-body launcher composed of four stages. The first three stages are solid propellant stages, while the fourth stage has a liquid propellant engine. Vega is 30 meters high, has a maximum diameter of three meters and a total of 137 tons at lift-off.

There are three main sections: the Lower Composite, the Restartable Upper Module and the Payload Composite.

The Lower Composite section consists of the first three stages (the solid propellant stages). The first stage is equipped with a P80-FW motor containing 88 tons of propellant. The second stage contains a Zefiro 23 motor with 23 tons of propellant. The third stage consists of a Zefiro 9 motor with 10 tons of propellant and the stage-interfacing structures.

The technology for the three solid-propellant stages (P80, Z23, Z9) is derived from the Zefiro 16 rocket motor. These motors benefit from the experience acquired by Europe in the field of solid propulsion. Each motor is composed of a thermal-insulated carbon-epoxy monolithic case, the solid propellant HTPB 1912, a nozzle, a thrust vector control system driven by two electro-actuators that operate the movable nozzle, and a control unit that provides pitch and yaw control during the flight. Each stage also includes an ignition subsystem, a safety subsystem, and the interfaces to the other stages.

Credits: ESA/CNES-SOV

The P80 engine was designed for the Vega small launcher, and it helps validate technologies applicable to a new generation of solid boosters for the Ariane 5 launch vehicle. This new design was driven by the goal of minimizing recurring costs, a significant reduction being made with respect to the current metal case boosters.

The Restartable Upper Module is the fourth stage of the launcher. It is also known as the Altitude and Vernier Upper Module (AVUM). The AVUM consists of two modules: the AVUM Propulsion Module and the AVUM Avionics Module.

The propulsion system uses NTO (Nitrogen Tetroxide) and UDMH (Unsymmetrical dimethyl hydrazine) as propellants. The propellants are stored in two identical titanium tanks pressurized by helium. Depending on the mission, the propellant load can be between 250 kg and 500 kg.

The avionics system is largely adapted from existing hardware and/or components already under development (namely subsystems already in use by the Ariane 5 launch vehicle).

The Payload Composite section is composed of the fairing and the payload/launcher interface structure. The fairing is composed of two shells that are jettisoned during flight after the separation of the second stage. The payload/launcher interface is an Adaptor 937, which is a standard interface used on the European launchers. Additional payload adapters can be added for multi-payload missions.

Credits: ESA – J. Huart

The dedicated Ground Segment for the Vega launcher comprises of the Launch Zone (ZLV – Zone de Lancement Vega) and the Operational Control Center, all located at the European Spaceport at Kourou, in French Guiana. ESA also built a Payload Preparation Complex that will be used for satellite and equipment unpacking, mechanical inspections, the checkout of the payloads, and the final integration of the payload composite before mounting it on top of the launcher.

On October 24, 2008, the Zefiro 9 rocket engine passed the first qualification test. There is one additional firing test left for the engine. The Vega launcher’s qualification flight is scheduled to take place by the end of 2009.

Credits: Avio SpA (Italy)

ESA is responsible for the qualification of the launch service and also for sustaining the qualification status during the exploitation phase. Ariane Space will be responsible for Vega’s commercialization and launch operations. The expected launch rate for Vega will be up to four launches per year.

Please stay tuned on the OrbitalHub frequency. We will keep you posted!

Credits: ESA/AOES Medialab

In a previous post, we presented the Planck spacecraft. We would like to dedicate this post to Planck’s big brother, Herschel. Why b(r)other? Because Planck and Herschel will be launched into space by the same Ariane 5 launcher and they will share the fairing section during the launch phase of the mission. Why big? Well, because Herschel is a larger spacecraft than Planck… actually Herschel is the largest space telescope ever built.

Just to have an idea about the size of the infrared telescope onboard the Herschel spacecraft, the primary mirror has a diameter of 3.5 m and a mass of only 350 kg. In comparison, the mirror of the Hubble space telescope has a diameter of 2.4 m and a mass of 1.5 tons. Obviously, a great deal of effort has been put into minimizing the mass of the telescope, an advance made possible by present-day technology.

The infrared telescope will become operational four months after its launch and will have a nominal mission lifetime of three years. The objectives that ESA set for the Herschel Space Observatory are ambitious: the study of the galaxies in the early universe, the investigation of the creation of stars, the observation of the chemical composition of the atmosphere and surfaces of comets, planets and satellites, as well as examining the molecular chemistry of the universe.

Like Planck, Herschel will observe the sky from the second Lagrangean Point (L2) of the Sun-Earth system. The instruments onboard Herschel will collect long-wavelength infrared radiation. Herschel will be the only space observatory to cover the spectral range from the far infrared to sub-millimeter, which is the reason why the initial name of the space observatory was Far Infrared and Sub-millimeter Telescope (FIRST).

Credits: ESA

The Herschel spacecraft will have 3.3 tons at launch, with a length of 7.5 m and a cross section of 4×4 m. The spacecraft comprises of two modules: the service module and the payload module. While the service module contains the systems for power conditioning, attitude control, data handling and communications, and the warm parts of the scientific instruments, the payload module contains the telescope, the optical bench, the cold parts of the scientific instruments and the cooling system. A sunshield protects the telescope and the cryostat from solar radiation. The sunshield also carries solar cells for power generation.

In order to make accurate observations of the infrared spectrum, parts of the scientific instruments onboard have to be cooled to temperatures close to absolute zero. Two thousand liters of liquid helium will be used for primary cooling during the mission. In addition, each detector onboard is equipped with additional cooling systems.

Credits: ESA/Guarniero

Herschel will not be the first infrared telescope launched into space. There are three predecessors that we would like to mention here: IRAS, the US-Dutch-British satellite launched in 1983, ISO – launched by ESA in 1995, and the NASA’s Spitzer Space Telescope – launched in 2003. However, these three infrared space telescopes were operated on Earth orbits. As we mentioned, Herschel will operate in the L2 point, away from any interference that would affect the scientific instruments onboard. Operating in the L2 point will also help with regard to thermal stability because the spacecraft will not move in and out of eclipse regions.

The launch date is set for early 2009. The journey to the final operational position will take around four months. The European Space Operations Control Center (ESOC) in Darmstadt will coordinate the mission.

Credits: NASA

In the previous two posts in this series, we presented NASA’s Lunar Reconnaissance Orbiter (LRO) and the Chandrayaan-1 mission, which was designed and developed by ISRO. These two missions are typical lunar scouting missions: the spacecraft with onboard remote-sensing instruments will orbit the Moon, collect scientific data, and relay it back to Earth.

NASA will launch another lunar scouting spacecraft on the same Atlas V rocket with LRO: the Lunar Crater Observation and Sensing Satellite (LCROSS). This mission is not a typical scouting mission and we will see why in this post.

In 1999, a precursor of LRO and LCROSS called the Lunar Prospector detected traces of concentrated hydrogen at the lunar poles. As a result, the LCROSS mission’s main goal is to confirm the presence or absence of water in a permanently shadowed crater near a lunar polar region. At the present time, landing a probe on the lunar surface and performing excavations or drilling would be very expensive. A less expensive solution for the LCROSS mission is to use a kinetic impactor to excavate a crater on the surface of the Moon.

Credits: NASA

After the launch, LRO will separate from LCROSS, and continue on a solo journey to the Moon. LCROSS will remain attached to the Centaur upper stage of the Atlas V launch system.

While LRO will follow a trajectory that will place it in a polar lunar orbit, LCROSS will execute a flyby of the Moon, and use an elongated Earth orbit to position itself on an impact trajectory. During this time, the LCROSS mission team will perform instrument calibration and corrections for the impact trajectory. The target of the impact will be the lunar south pole.

Seven minutes before the impact, LCROSS will separate from Centaur. The Centaur will be used as a kinetic impactor. Having a mass of approximately 2,200 kg, on impact, it will excavate a crater 20 meters wide and 3 meters deep. According to NASA scientists, more than 250 tons of lunar material will be propelled into space.

Credits: NASA

LCROSS will then fly through the debris of the previous impact. The instruments onboard LCROSS will collect scientific data and the spacecraft will relay it back to Earth. LCROSS will end its mission four minutes after the Centaur impact by creating its own impact crater on the lunar surface. The last S in LCROSS should stand for Smasher instead of Satellite considering the final act of the mission!

The scientific instruments onboard LCROSS cover a wide spectrum: two near-infrared spectrometers, a visible light spectrometer, two mid-infrared cameras, two near-infrared cameras, a visible camera, and a visible radiometer. The instruments can detect traces of organics, hydrocarbons, hydrated minerals, water ice, and water vapor. More details about the LCROSS scientific payload can be found on LCROSS mission page.

I wonder to what extent the debris caused by the impact of Centaur and LCROSS will interfere with the scientific instruments onboard LRO and Chandrayaan-1. Both LRO and Chandrayaan-1 will be orbiting the Moon on polar orbits at that time.

Credits: ESA

ESA is about to launch a satellite capable of measuring very small variations in the Earth’s gravitational field. Even if it is a common-sense assumption that the force of gravity on the surface of the Earth has a constant value, there are subtle variations caused by the rotation of the Earth, the position of the mountains and ocean trenches, and by the variations of the Earth’s inner density. Determining the variations in the Earth’s gravitational field will improve our knowledge of ocean circulation, and will also help to make advances in geodesy and surveying.

The Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite will measure the small variations of the gravitational field. GOCE is the most advanced gravity space mission to date. Scientists will build a detailed map of Earth’s gravity using data collected by GOCE.

Credits: ESA

In order to make accurate measurements, the GOCE satellite will orbit in a low altitude orbit, around 250 km above the surface of the Earth.

An elongated shape has been chosen for the satellite design to minimize the atmospheric drag. GOCE is five meters long, one meter in diameter, and has a mass of roughly 1050 kg.

The heart of the GOCE satellite is a scientific instrument called gradiometer. The gradiometer consists of three pairs of accelerometers, and it measures acceleration variations over short distances between proof masses inside the satellite. One important thing to mention here is that the calibration of the gradiometer takes place after launch. The reason? The instrument cannot be calibrated on the ground, under the force of gravity.

Credits: ESA

You can find out more about the calibration of the GOCE instrument by reading an interesting article on ESA’s website.

Daniel Lamarre, a Canadian national working at ESA’s European Space Research and Technology Centre (ESTEC), is the inventor and the developer of the method used for the calibration of the instrument. He won an ESA award for developing the calibration method.

The GOCE satellite will be launched from the Plesetsk Cosmodrome in northern Russia. Eurockot Launch Services GmbH, a company that provides commercial launch services with the Rockot launch system, will be the launch provider for the GOCE mission. Eurockot was formed in 1993. EADS Astrium, located in Bremen, Germany, holds 51 percent of the company. The Khrunichev State Research and Production Space Center in Moscow, Russia, owns the remaining 49 percent.

Credits: ESA

The Rockot launcher is based on the SS-19 Intercontinental Ballistic Missiles. The upper stage of the launch system, Breeze KM, extends the performance capabilities of the Rockot lower stages. The system is capable of injecting a 1950 kg payload into Low Earth Orbit (LEO). The re-ignitable main engine of the Breeze KM allows various injection schemes for the payload. The length of the launch vehicle is 29 meters, with a launch mass of 107 tons. The external diameter of the three stages is 2.5 meters, while the payload fairing has an external diameter of 2.6 meters and a height of 6.7 meters.

The initial launch date was postponed due to an anomaly identified in the guidance and navigation subsystem of the Breeze KM upper stage. The new launch date has been scheduled for Monday, October 27th, 2008.