OrbitalHub

Credits: ESA-AOES Medialab

The Soil Moisture and Ocean Salinity (SMOS) mission, which is the second Earth Explorer Opportunity mission to be developed as part of ESA’s Living Planet Program, will provide global maps of moisture over the Earth’s landmasses and salinity over the oceans. These observations will improve our understanding of hydrology and ocean circulation patterns.

The science objectives for the SMOS mission are global monitoring of surface soil moisture and surface salinity over oceans, and improving the characterization of ice and snow-covered surfaces.

The SMOS satellite is built around a standard spacecraft bus called Proteus, which was developed by the French space agency CNES (Centre National d’Etudes Spatiales) and Alcatel Alenia Space. Proteus measures one cubic meter and plays the role of a service module, hosting all the subsystems that are required for the satellite to function.

A GPS receiver collects satellite position information. A hydrazine monopropellant system consisting of four 1-Newton thrusters, which are mounted on the base of the spacecraft, provides the thrust for orbit control. Three 2-axis gyroscopes and four small reaction wheels control the attitude of the satellite. A star tracker also provides accurate attitude information for instrument measurements.

The solar panels can produce up to 900 W, covering the 525 W maximum payload consumption. During eclipse periods, the satellite uses a 78 AH Li-ion battery. SMOS has a launch mass of 658 kg: a 275 kg platform, 355 kg payload, and 28 kg of fuel.

The SMOS satellite will deploy a new type of scientific instrument in space: a microwave imaging radiometer that operates between 1,400 – 1,427 MHz (L-band). The instrument is called Microwave Imaging Radiometer using Aperture Synthesis, or MIRAS, for short. MIRAS consists of a central structure and three deployable arms, and uses 69 antenna-receivers (LICEFs) for measuring microwave radiation emitted from the surface of the Earth. The instrument is the result of almost ten years of research and development.

Credits: ESA-AOES Medialab

The data collected by MIRAS needs to go through a validation process. The radiation received by the instrument is a function that depends not only on soil moisture and ocean salinity, other effects need to be considered when instrument data is converted into units of salinity and moisture.

Factors that have to be considered are the distribution of vegetation, the litter layer, the soil type, the varying roughness of the surface, and the physical temperature of the surface of the land and sea.

In order to quantify the effects of factors mentioned above, dedicated campaign activities were conducted. Ground-based and airborne instruments similar to the one mounted on SMOS were used to collect data that was correlated with in-situ observations made by large ground teams. Long-term observations were carried out from an oilrig platform in the Mediterranean and at the Concordia Station in Antarctica.

The Committee on Earth Observation Satellites (CEOS) has defined a number of levels for the SMOS Mission Data Products. They range from Raw Data to Level-3 Data Products, which are Soil Moisture and Ocean Salinity global maps. Level-3 data will be available from the SMOS Level 3/4 Processing Center in Spain.

Eurockot will provide the launch services for the SMOS mission. A Rockot launcher, which is derived from a Russian Intercontinental Ballistic Missile (ICBM) SS-19, will lift off from the Plesetsk Cosmodrome, 800 km north of Moscow. The Rockot launcher will inject the satellite in a 758 km quasi-circular orbit.

The CNES Satellite Operations Ground Segment and ESA/CDTI (Centro para el Desarrollo Technologico Industrial) Data Processing Ground Segment will be responsible for the SMOS mission ground segment.

Initially scheduled for 2008, the launch of the Earth Explorer SMOS satellite will take place some time from July to October 2009.

You can find more details about SMOS on the dedicated page on ESA’s web site.

Credits: ESA

The Kennedy Space Center has officially welcomed Node 3. Node 3 is a European-built module for the International Space Station (ISS). The prime contractor chosen for the job was Thales Alenia Space, in Turin, Italy.

Node 3 was transported from Italy by an Airbus Beluga aircraft. The aircraft left Turin on May 17, and arrived in Florida on May 20.

Node 3 is now being prepared for the journey to the ISS in the Space Station Processing Facility (SSPF) at KSC.

Node 3 is a connecting module. With a length of 6.7 m and 4.4 m in diameter, Node 3 will have a total mass of 19,000 kg once berthed to the ISS. Node 3 will eventually house the life support system necessary for the permanent crew of six on the space station. On one of its berthing ports, Node 3 will accommodate the Cupola. Node 3 also provides room for eight refrigerator-size racks. Two of these racks will be used by avionics systems controlling the node.

Credits: ESA

Cupola is an observation module. Once attached to Node 3, it will provide a pressurized observation and work area for two ISS crew members. Cupola will allow the crew to control the space station remote manipulator system through the robotic workstation. Cupola has a mass of 1,880 kg, a height of 1.5 m, and it has a maximum diameter of 2.9 m. The windows are protected by a Micro-meteorid and orbital Debris Protection System (MDPS), which consists of shutters made out of aluminum coated with Kevlar.

Node 3 will be launched inside the Orbiter cargo bay, mounted on a pallet via a Manual Berthing Mechanism, and transferred to the Node location using the Shuttle Remote Manipulator System.

“Node 3 represents a turning point for the International Space Station,” said Simonetta Di Pippo, ESA Director of Human Spaceflight. “By having accomplished the development of the ISS modules and by completing its assembly in the months to come we open a new avenue of cooperation and exploration that will take humankind back to the Moon and beyond to other destinations while continuing to exploit the enormous possibilities in low Earth orbit.”

Credits: ESA

NASA has chosen the name Tranquility for Node 3, after the Sea of Tranquility, landing site of Apollo 11 in 1969. Colbert had to settle for having one of the treadmills onboard ISS named after him.

Node 3 and Cupola are scheduled to be delivered to the ISS by STS-130 Space Shuttle Endeavour in early 2010.

You can find out more about Node 3 and Cupola on the page dedicated to the ISS on ESA’s web site.

Credits: NASA/ESA

The Hubble Space Telescope (HST) is a joint creation of NASA, ESA, hundreds of industrial companies, government and university groups, and thousands of engineers and scientists. Since April 1990, when it was released into orbit from Discovery’s payload bay, Hubble has returned scientific data and stunning images of stars, nebulae, and distant galaxies.

The construction of the space telescope began in the 1980s, when the optics company Perkin-Elmer initiated the work on Hubble’s primary light-collecting mirror. The Hubble Space Telescope was completed in 1985, but was not deployed in Earth’s orbit for another five years.

In 1983, the Space Telescope Science Institute (STScI) was founded and it assumed from NASA the science management of the Hubble Space Telescope. STScI is located at Johns Hopkins University.

In its initial configuration, Hubble carried the Wide Field and Planetary Camera (WF/PC), the Goddard High Resolution Spectrograph (GHRS), the Faint Object Camera (FOC), and the Faint Object Spectrograph (FOS). It was soon to be discovered that the primary mirror had a flaw, and that the space telescope suffered from blurry vision.

The Hubble Servicing Mission 1 installed a corrective optics package, COSTAR, and replaced the original WF/PC with the Wide Field and Planetary Camera 2. Hubble Servicing Mission 2 replaced the GHRS and FOS with the Space Telescope Imaging Spectrograph (STIS) and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). Servicing Mission 3A replaced all six gyroscopes, a Fine Guidance Sensor, and the onboard computer. Servicing Mission 3B saw the installation of the Advanced Camera for Surveys (ACS), which replaced the FOC, and the revival of NICMOS through the installation of a new cooling system.

All this, and the history of astronomic discoveries beginning with Galileo Galilei in 1609 and continued by William Herschel, William Huggins, George Ellery Hale, and Edwin Hubble, are presented in Hubble – Imaging Space And Time, a book authored by David DeVorkin and Robert W. Smith. The book is replete with spectacular images captured by the Hubble Space Telescope. Images of Carina Nebula, Eagle Nebula, Orion Nebula, and Swan Nebula, just to name a few, are a celebration of color and convey the majestic beauty of the Cosmos.

David DeVorkin is curator of the history of astronomy and the space sciences at the National Air and Space Museum, Smithsonian Institution. Among other books he has authored are Beyond Earth: Mapping the Universe and The Hubble Space Telescope: Imaging the Universe.

Robert W. Smith is a professor of history and Director of the Science, Technology and Society Program at the University of Alberta. He is also the author of The Space Telescope: A Study of NASA, Science, Technology and Politics, The Hubble Space Telescope: Imaging the Universe, and The Expanding Universe.

Credits: ESA

After a successful launch from the Plesetsk Cosmodrome in northern Russia by a Rockot launch vehicle, GOCE has to go through a number of preparation stages before becoming operational and starting to collect three-dimensional gravity data all over the globe.

On April 6, 2009, the GOCE’s propulsion system was switched on. The system was confirmed to be operating normally. Two days later, on April 8, 2009, the gradiometer was switched on as well. The instrument started to produce data instantly.

“With the ion engine and the gradiometer working, we have started to tune the satellite and its instruments,” GOCE System Manager Michael Fehringer said.

The payload, an Electrostatic Gravity Gradiometer, consists of six accelerometers mounted in pairs on three perpendicular axes on an ultra-stable carbon-carbon structure. Measurements of the tiny differences in the readings from the accelerometer pairs will render very accurate results for the geoid altitude and the detection of gravity-field anomalies.

Given the unique payload onboard the spacecraft, GOCE has to provide an undisturbed environment for the instruments. Two additional accelerometers mounted on the velocity axes will control the two low-power xenon ion engines in order to compensate for the atmospheric drag. The ion engines each can provide only 1 to 20 milli-Newtons of thrust, which does not sound like very much, but it is enough to overcome the drag experienced by the spacecraft in orbit.

GOCE has been losing altitude at a rate of 150m to 200m a day, until May 26, 2009, when the spacecraft entered the drag-free mode.

Rune Floberghagen, ESA’s GOCE Mission Manager, stated that, “Knowing that the drag-free control system works perfectly means we now have everything in place to carry out the complex process of calibrating the gradiometer instrument. Once calibration has been completed we will be able to see the true excellence of GOCE’s gravity-field measurements.”

The instruments have to undergo a further six weeks of commissioning and calibration. Mission operations are scheduled to start in summer 2009.

You can read more about the GOCE mission on the dedicated page on ESA’s web site.

Credits: NASA

STS-125 Space Shuttle Atlantis was the final Hubble Space Telescope servicing mission (SM4). The STS-125 crew consisted of Gregory C. Johnson, pilot; Scott D. Altman, commander; Michael J. Massimino, Michael T. Good, K. Megan McArthur, John M. Grunsfeld, and Andrew J. Feustel, all mission specialists.

STS-125 has some history behind it. In 2004, NASA head Sean O’Keefe cancelled the long-planned Hubble Space Telescope Servicing Mission 4, invoking new safety rules that were applied to space shuttle flights after the Columbia disaster. By June 2004, NASA was considering a robotic servicing mission, which was also cancelled due to prohibitive costs. A change in NASA policy came with the new head of NASA, Michael Griffin. The risks associated with the SM4 mission were reassessed, and by 2008 SM4 was back on track.

On May 11, 2009, STS-125 Space Shuttle Atlantis launched at 2:01 PM EDT. There were no obvious debris events during launch and after going through the post-launch checklist, the crew prepared the orbiter for in-orbit operations and conducted a survey of the payload bay and the crew cabin using the robotic arm.

On May 13, 2009, at 17:14 UTC, flight day #3, Hubble Space Telescope was grappled and by 18:12 UTC, the telescope was berthed in the payload bay of Atlantis.

There were a total of five EVAs performed by the STS-125 crew. During EVA#1 (John Grunsfeld/ Andrew Feustel), the Wide Field and Planetary Camera 2 (WFPC2) was replaced with the new Wide Field Camera 3 (WFC3), and the Science Instrument Command and Data Handling Unit were replaced. A Soft Capture Mechanism (SCM) was also installed on Hubble. SCM will be used to capture and de-orbit Hubble at the end of its operational life. EVA#2 (Michael Massimino/ Michael Good) replaced all three gyroscope rate sensing units (RSUs) and one of the battery unit modules. EVA#3 (John Grunsfeld/ Andrew Feustel) removed and replaced COSTAR with the Cosmic Origins Spectrograph, and replaced faulty electronics cards from the Advanced Camera for Surveys. EVA#4 (Michael Massimino/ Michael Good) removed and replaced electronics cards for the Space Telescope Imaging Spectrograph (STIS). EVA#5 (John Grunsfeld/ Andrew Feustel) replaced the second battery unit module, installed the Fine Guidance Sensor #3, replaced degraded insulation panels with New Outer Blanket Layer (NOBL)s, and also replaced a protective cover around Hubble’s low-gain antenna.

Hubble was released on May 19, 2009 (flight day #9). The telescope was lifted out of the orbiter’s payload bay using the robotic arm. After running through the release checklist, the STS-125 crew released Hubble at 12:57 UTC. The new equipment and the upgrades installed on Hubble will be tested for several months before resuming operation in early September.

Due to weather, which was less than favorable for landing, STS-125 had to delay the return to Earth for two days. The de-orbit burn was initiated on May 24, 2009, at 14:24 UTC.

STS-125 Space Shuttle Atlantis landed at Edwards Air Force Base in California, on Sunday May 24, 2009, at 11:39 AM EDT.

Credits: ESA – D. Ducros, 2009

While the media has been busy with the launch of the STS-125 Atlantis for the Hubble Servicing Mission #4 from Cape Canaveral, another exciting launch is undergoing preparations further south, in Kourou, French Guiana.

Herschel and Planck are scheduled to launch on May 14, 2009. They will be stacked on the same Ariane 5 launch vehicle.

The two spacecraft will separate shortly after the launch (Herschel a couple of minutes before Planck) and will proceed independently to the L2 point of the Sun-Earth system. L2 is a point in space that has some special characteristics situated at 1.5 million kilometers from Earth in the opposite direction to the Sun. Herschel and Planck will operate from independent orbits around the L2 point.

Credits: ESA – D. Ducros, 2009

Stacked together, Herschel and Planck measure around 11 m in length, 4.5 m in diameter, and have a mass of approximately 5,700 kg. The piece that holds them together is called Sylda. Sylda is a support structure for Herschel and forms a protective cover for Planck.

The final orbit for Herschel will be a large, 900×500-thousand km, Lissajous orbit around the L2. There are three trajectory-correction maneuvers (TCM) planned for Herschel, during days L+1, L+2, and L+12. Planck will require a total of 5 TCMs that will enable it to operate from a 300×200-thousand km Lissajous orbit also around the L2 point.

The Lissajou orbits are inherently unstable, so both spacecraft will need regular thruster burns throughout their missions to stay on track.

“Without regular trajectory corrections, they would naturally drift off into a useless orbit about the Sun or Earth, with the rate of drift increasing with time,” says Gottlob Gienger, the senior flight dynamics advisor for the Herschel and Planck missions.

To read more about the launch of Herschel and Planck, you can visit the dedicated page on ESA’s website.