SANSA plays a vital role in NASA’s OCO-2 satellite launch

nasas-orbiting-carbon-observatory-oco-2On 2 July 2014, NASA's Orbiting Carbon Observatory-2 (OCO-2) satellite was successfully launched from the Vandenberg Air Force Base in California. Minutes later, the Hartebeesthoek (HBK) ground station in South Africa acquired the rocket signal and was able to provide live video feed to United Launch Alliance (ULA).

ULA launched the Delta II rocket carrying the OCO-2 spacecraft at 11:56 CAT. At 12:45 CAT, the South African National Space Agency (SANSA) acquired the rocket signal. "Our coverage included the second stage burn-2 and live video footage of the spacecraft separation," explains Yunus Bhayat, Operations Manager at SANSA Space Operations. "SANSA's exclusive location and technical expertise put us in a position to monitor these key events, as they take place over the African airspace," Bhayat adds.

SANSA supports Curiosity, MOM and LADEE

Did you know that the South African National Space Agency is involved in many of the global space missions currently under way?

The Space Operations directorate provided launch support for the Mars Curiosity mission launched from Cape Canaveral Air Force Station in Florida on 25 November 2011. The 950kg Mars Science Laboratory (MSL) spacecraft housing Curiosity, larger than any of its predecessors, separated from the launch vehicle while over African airspace and SANSA monitored it on NASA's behalf. Curiosity travelled 567 million kilometres to Mars, has a power nuclear source and has been working around the clock for nearly 300 days.

More recently, SANSA supported its second Mars mission when the Indian Space Research Organisation (ISRO) contracted the agency to provide tracking, telemetry and command services for the first Asian mission to Mars – the Mars Orbiter Mission (MOM). SANSA's Hartebeesthoek ground station was specifically chosen because it's "ideally located to be the closest point to the satellite per pass," says Pandey Shyam, an ISRO scientist stationed at SANSA for the duration of the testing. The Martian orbiter is set to reach its destination in September this year, with a scheduled trajectory correction in August. Its total journey is around 480 million kilometres, of which it has completed about two-thirds.

The NASA Lunar Atmosphere and Dust Environment Explorer (LADEE), or "laddie", was also supported by SANSA. LADEE collected data to better scientists' understanding of solar bodies like moons and asteroids. The robotic mission orbited the moon for six months, gathering information about the lunar atmosphere. On 18 April 2014, LADEE was intentionally allowed to run out of fuel and crash into the Moon's surface, ending the mission.

Hi, my name is Mangalyaan

The Mars orbiter is also known as Mangalyaan, which means Mars-craft in Hindi

 

 

 

 

 

 

A short story about a very clever pole called Doris

On a hill just south of the Magaliesberg in Gauteng, at SANSA's space operations Hartebeesthoek facility, there is a short pole called Doris. To the casual observer it's just a simple white pole with chipped paint and some electric wiring down the side. Lost in the sea of imposing antennas and other equipment, it really doesn't look like anything special.

To the space operations industry, however, Doris the pole is a sophisticated piece of equipment vital to the aviation industry and worthy of daily monitoring and attention.

The biggest physical task for Doris is to stand still in a fixed position. This is not so easy in soil which naturally expands and contracts with temperature changes, so Doris consists of steel pipe filled with cement and sunk into a hole drilled into the bedrock. The steel pipe, perforated for the first four metres, has a 10mm thick wall and a diameter of 28cm. Once it was sunk into the six metre deep hole, it was filled with concrete and vibrated to let the concrete seep through the perforations, binding to the bedrock wall. Thus, an incredibly stable platform was created for the highly sensitive sensor.

Mounted on Doris is a Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) transmitter system which works with satellite payloads to determine extremely precise orbit and ground locations. These transmitters, on poles just like this one around the world, send signals from their fixed locations to satellites in low Earth orbits. South Africa hosts another DORIS antenna on Marion Island, which was upgraded by Pierre Cilliers from SANSA in 2010.

The system was designed by the French space agency CNES to determine the precise orbit locations required for observing Earth's oceans. Doris data has also become valuable in geophysics, helping researchers to measure continental drift, monitor geophysical deformations, and determine the rotation and gravity parameters of Earth.

SANSA's Carlos de Oliveira looks after Doris, knowing that any malfunction would cause a blind spot in a global network which is used extensively in navigation.

The national mapping and surveyor agency in France, the IGN, uses data from Doris to contribute to the international reference system, and a Doris beacon on the Dorsal Glacier in East Antarctica is providing data on the movement of ice in this remote location.

The Doppler Effect and Malaysian flight MH370

The Doris system is based on the Doppler Effect. Austrian physicist Christian Doppler theorised that a quantifiable effect is observed when a source of light or sound waves is moving in relation to a stationary observer. This principle is now used in a variety of location-orientated applications. Recently, Inmarsat 4-F1 communications satellite engineers identified two paths that the missing Malaysian flight MH370 could possibly have taken by using the Doppler Effect and data from their satellite.

 

 

 

 

 

 

Staying competitive

Ka-band antenna upgrade gives Space Ops the international edge

A recent Ka-band antenna upgrade is putting SANSA Space Operations at Hartebeesthoek in a uniquely competitive position to monitor a new wave of satellites launched over the southern hemisphere.

In 1997 Hartebeesthoek installed the first Ka-band telemetry, tracking and command (TT&C) antenna to support the launch of a US Ka-band satellite constellation which broadcast to three American television networks.

Installation and staff training on the antenna took nine months. For the next fifteen years, a small part of the Ka-band spectrum was used, and only irregularly. The Ka-band has recently become more popular as a satellite frequency, prompting SANSA to invest in an upgrade which will enable the Space Ops team to support more launches and in-orbit testing campaigns.

Having started in January 2014, the project includes the replacement of the antenna feed horn and all the equipment for receiving and transmitting the full commercial Ka-band. Acceptance testing has been completed and the antenna is ready for its first mission.

By updating the antenna, SANSA is able to offer clients the entire range within the Ka-band frequency, thus creating new possibilities for international business and partnerships.

 

What is a Deorbit?

corot2

The CoRoT satellite, from website: http://physicsforme.files.wordpress.com/2011/06/corot2.gif

 

CoRoT deorbit: 17 June 2014

SANSA is currently providing support for the CoRoT satellite which belongs to the French space agency CNES. With assistance from the ground station, final TT&C manoeuvres to end the life of this satellite are executed together with other ground stations as it goes into deorbit.

CoRoT which stands for the COnvection ROtation and planetary Transits, is a space mission led by CNES, together with the European Space Agency (ESA) and other international partners.

The mission's two objectives are to search for extrasolar planets with short orbital periods, particularly those of large terrestrial size, and to perform asteroseismology by measuring solar-like oscillations in stars. The probe was launched on 27 December 2006 on the Soyuz 2.1b carrier rocket and reported first light on 18 January 2007.

CoRoT is the first spacecraft dedicated to the detection of transiting extrasolar planets, opening the way for more advanced probes such as Kepler as well as future missions such as TESS and PLATO.

SANSA is now playing a global role in the decluttering of space by providing deorbit support which has a main focus on removal of inactive or non-functional satellites. This is critical as without this capability, it will soon prove impossible to launch any future space missions as space junk continues to accumulate around our planet.

 

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