OrbitalHub

Credits: ESA – P. Carril

In 2007, projections of sea level rise made by the Fourth Assessment Report of the Intergovernmental Panel on Climate Change were in the range of 28–43 cm by 2100, but there are new projections of the sea level rise that are in the order of 1.4 m.

While the trend is quite obvious, it is very important to be able to make accurate predictions.

Cryosat has been designed to measure the ice thickness on land and also at sea, and will provide enough data so that a precise rate of change of the ice thickness can be determined. A better understanding of how the volume of ice on Earth is changing will also be possible.

The declared primary goals of the CryoSat mission are to determine the regional trends in Arctic perennial sea-ice thickness and mass, and to determine the contribution that the Antarctic and Greenland ice sheets are making to mean global rise in sea level. Cryosat will also measure the variations in the thickness of Earth’s polar caps and glaciers. The spacecraft will be operational for a minimum of three years.

Credits: ESA/P. Carril

The spacecraft has a launch mass of 720 kg, of which 23 kg is the fuel required for orbital maneuvers and attitude corrections. The overall size of the spacecraft is 4.6 m x 2.34 m. Two solar panels are attached to the spacecraft’s body and provide a maximum of 800 W of power. As the CryoSat-2 orbit is not Sun-synchronous, providing enough power to the scientific payload has been a considerable challenge.

The operational orbit will be a 717 km non Sun-synchronous orbit with a 92 degree inclination.

The primary payload of the CryoSat-2 spacecraft is the SAR/Interferometric Radar Altimeter (SIRAL). In order to have the position of the spacecraft accurately tracked, a radio receiver called Doppler Orbit and Radio Positioning Integration by Satellite (DORIS) and a laser retro-reflector are part of the payload as well. A global network of laser ranging stations (the International Laser Ranging Service or ILRS for short) will support the mission. Three star-trackers will ensure a proper orientation of the spacecraft.

Using the Synthetic Aperture technique, CryoSat-2 measurements taken by SIRAL will have a 250 m resolution in the along-track direction. The instrument is designed to operate in three measurement modes: Low Resolution Mode (LRM) mostly over the oceans, Synthetic Aperture Radar (SAR) mode over sea-ice areas, and SAR Interferometric (SARIn) mode over steeply sloping ice-sheet margins, small ice caps, and mountain glaciers.

Credits: ESA – AOES Medialab

CryoSat-2 will be placed in orbit by a Dnepr launch vehicle. With a lift-off mass of 211 tons, Dnepr is 34 m long and 3 m in diameter, and has three stages that use hypergolic liquid propellants (N₂O₄ nitrogen peroxide and UDMH unsymmetrical dimethylhydrazine). In addition, there are Dnepr configurations with a third and a fourth stage for missions that require more energy. The launch vehicle is based on an ICMB designated as SS-18 Satan by NATO. The development and commercial operation of the Dnepr Space Launch System is managed by the International Space Company (ISC) Kosmotras. Dnepr can lift 4,500 kg to low Earth orbit (LEO) or 2,300 kg to a 98 degree Sun-synchronous orbit. Among other satellites launched by Dnepr are Demeter, Genesis I, Genesis II, and THEOS. Dnepr, carrying Cryosat-2, will lift off from Baikonur Cosmodrome in Kazakhstan.

The Rockot launch vehicle that attempted the orbiting of the first CryoSat mission, on October 8, 2005, failed to reach orbit. Due to faults in the onboard software, the second stage engine of the launcher did not shut down. The mission was terminated when the launch vehicle exceeded the flight envelope limit. The Rockot second stage/Breeze-KM/CryoSat stack crashed somewhere in the Arctic Ocean.

You can find more information about Cryosat-2 on ESA’s dedicated website. The Cryosat-2 mission EADS team also has a blog on EADS Astrium website. Check out the latest updates from Baikonur brought to you by Klaus Jäger (Astrium Spacecraft Launch Manager) and Edmund Paul (Astrium Spacecraft Operations Manager). A presentation of the SIRAL-2 instrument is available on Thales Group’s website.

Credits: ESA/CNES/Arianespace РOptique vid̩o du CSG, L. Boyer

Arianespace was founded in 1980. With twenty-four shareholders from ten European countries (among which CNES holds 34% and EADS 30%), Arianespace is the world’s first commercial space transportation company.

The workhorse of Arianespace has been the Ariane launch vehicle.

Five versions of Ariane have served the company so far: Ariane 1, with the first successful launch on December 24, 1979, Ariane 2, launched for the first time on November 20, 1987, Ariane 3, starting its service on August 4, 1984, Ariane 4, launched on June 15, 1988, and Ariane 5, with the first successful flight on October 30, 1997.

The first launch of Ariane 5, a.k.a. Flight 501, ended with the vehicle being destroyed by its automated self-destruct system, after the high accelerations caused the inertial guidance system to crash. The crash was caused by, I quote, one of the most infamous computer bugs in history. If you like, you can take a look at the Ada code that caused the malfunction. But enough with the dark memories, this is an anniversary after all…

Since its inception, Arianespace has signed over 300 contracts that resulted in more than 277 satellite launches. According to Arianespace, Ariane launchers have delivered more than half of all commercial satellites now in service. The year 2009 was a very successful year for Ariane 5. The launcher orbited nine commercial satellites, the Herschel space telescope, the Planck scientific observatory, and the Helios 2B observation satellite. Ariane 5 has proven to be a versatile launch vehicle, capable of handling a wide range of missions.

The challenges for 2010 are many, as Arianespace is planning up to seven Ariane 5 launches. Two new launch vehicles will join Ariane 5 as part of the Arianespace family of launchers: the Vega small launcher and the Soyuz medium launcher.

You can read more about Arianespace, its mission, and the solutions provided to customers around the world on the Arianespace website.

Credits: ESA/CNES/ARIANESPACE-Service Optique CSG 2002

Arianespace accounted for 50 percent of all commercial launches to geostationary transfer orbit during 2008 and retained its strong market share, which represented 72 percent of the orders booked in 2008.

Arianespace was founded in 1980. Among its 23 shareholders are the French space agency CNES with thirty-four percent and EADS Astrium with thirty percent. With only around 300 employees, the company has generated sales of about one billion euros in 2008.

2009 will be the year of the launcher family for Arianespace, as Arianespace Chairman and CEO Jean-Yves Le Gall pointed out during the company’s New Year’s press conference in Paris. The development of the Vega launcher is being finalized, the maiden launch of the medium-lift Soyuz launcher from Kourou in French Guiana will take place this year, and more than six missions are scheduled for Ariane 5.

“As a result of our launcher family strategy, Arianespace has a sustained agility that allows us to be ever more responsive to our customers,” Le Gall told the journalists. “The agility has been demonstrated with our 28 consecutive mission successes for Ariane 5 and the 21 for Soyuz – and is underscored by launches that are on target, and on time.”

With a full range of payload lift capabilities, including Vega, Soyuz, and Ariane 5, Arianespace is able to meet the changing trends in satellite weights, orbiting everything from light weight scientific payloads to heavy telecommunication relay platforms.