Radio astronomers record final moments of SMART-1 spacecraft
The impact occurred at about 05:42 UT (07:42 CEST)
Sunday 3 September 2006, when the Moon was below
the horizon in Europe. European telescopes were
unfavorably located to observe the impact, but the Medicina
32-m Radio Telescope (Istituto di Radioastronomia, INAF, Bologna, Italy)
paid tribute to the mission by recording the last
final transmission of SMART-1 over Europe about 11
hours before impact. Later, monitoring continued as
European radio astronomers received and recorded
radio transmissions from the spacecraft using the ROEN
(Northeastern Space Radio Observatory, Fortaleza,
Brazil), Transportable Integrated Geodetic Observatory
(TIGO, Concepcion, Chile), Mt. Pleasant Observatory
(Hobart, Australia) and the CSIRO
Australia Telescope Compact Array (Narrabri, NSW,
Australia). All five telescopes operated in Very Long
Baseline Interferometry (VLBI) mode. The data from VLBI
monitoring of SMART-1 is being processed at JIVE.
VLBI permits signals received at multiple radio
telescopes to be used together to produce images of
celestial radio sources with extremely high resolution.
Data from all five radio telescopes observing
SMART-1 during the last hours of the mission will
be processed at JIVE using software first developed
and used for tracking of ESA's Huygens Probe during
its descent through Titan's atmosphere in January
2005. The strength of the signal received by all
five telescopes combined with SMART-1's close
proximity, only meters from the surface before impact,
will enable analysis of very fine physical phenomena
of the Moon.
The SMART-1 mission was conceived by ESA as
a pathfinder of new technologies, particularly
in the area of propulsion and "science reconnaissance."
The VLBI experiment, as the latest addition to the
SMART-1 science programme, perfectly complements the
mission's purpose of innovation. It paves the way
for future applications of the VLBI technique for
prospective planetary probes. These applications
will include experiments that require extremely
accurate time and position measurements. They
will also allow radio astronomers to detect very
weak radio phenomena associated with the physical properties
of planets and other celestial bodies. These
experiments will address such diverse areas of
science as comparative planetology and fundamental physics.
Additionally, a portion of data from the TIGO
telescope in Chile and the Mt. Pleasant Observatory
in Australia was sent to JIVE as part of the EXPReS
project (Express Real-time e-VLBI Service)
coordinated by JIVE and funded by the European
Commission (DG-INFSO). e-VLBI is a type of VLBI
which uses optical networks to connect the
telescopes in real-time, creating a distributed
radio telescope of continental and intercontinental
dimensions. This data transfer
was made possible by close collaboration of the
REUNA (Chile), RedCLARA (South America), GÉANT2
(Europe) and SURFnet (Netherlands) networks.
Using e-VLBI techniques, astronomers at JIVE received an
important 10 seconds of data concerning the precise
time and velocity at impact from Chile and Australia
in a matter of seconds, and additional data were
transferred and processed in a matter of hours.
With this data astronomers were able to determine
the time of impact within 10 microseconds (10
millionths of a second), equating to two centimeters
along the spacecraft's trajectory.
This and earlier observations of SMART-1
validate the use of e-VLBI and ground observations
for tracking future lunar and planetary missions
such as China's Chang'E-1 Lunar orbiter, scheduled
for launch in 2007.
About JIVE
About EXPReS
# # #
Contact:
Kristine Yun, Public Outreach Officer
Links:
Credits:
DWINGELOO,
The Netherlands (4 September 2006) --
The European Space Agency's SMART-1 spacecraft
completed its almost three year mission early Sunday
with a controlled impact with the surface of the Moon.
A network of radio telescopes, led by European radio
astronomers from the Joint Institute for VLBI in
Europe (JIVE, Dwingeloo, the Netherlands) observed
SMART-1 and recorded key data during its final
moments and impact.
The Joint Institute for VLBI in Europe (JIVE,
www.jive.nl) was established as a scientific foundation in December 1993.
JIVE’s mandate is to support the operations of the European
VLBI Network (EVN) in the widest sense. The major activity
has been the development, construction and successful
operation of the EVN Data Processor, a powerful supercomputer
that combines the signals from radio telescopes located
across the planet, creating one huge telescope of
intercontinental dimensions. Using this technique of Very
Long Baseline Interferometry (VLBI), astronomers can
make detailed images of cosmic radio sources, providing
astronomers with the clearest, highest resolution view of
some of the most distant and energetic objects in the Universe.
Express Production Real-time e-VLBI Service
(EXPReS, www.expres-eu.org), is a three-year project funded
by the European Commission with the objective of creating
a distributed, large-scale astronomical instrument of
continental and intercontinental dimensions. This electronic
Very Long Baseline Interferometer (e-VLBI) is achieved using
high-speed communication networks operating in real-time and
connecting together some of the largest and most sensitive
radio telescopes on the planet. EXPReS is coordinated by
JIVE, the Joint Institute for VLBI in Europe (www.jive.nl),
which is hosted by ASTRON, the Netherlands Foundation
for Research in Astronomy (www.astron.nl), in Dwingeloo.
Dr Leonid Gurvits
Joint Institute for VLBI in Europe (JIVE)
+31 521-586514 (office)
+31 529-015149 (mobile)
lgurvits@jive.nl
Express Production Real-time e-VLBI Service (EXPReS)
Joint Institute for VLBI in Europe
+31 521-596543
kyun@jive.nl
www.expres-eu.org
