The SMART-1 spacecraft is currently expected to impact the Moon's surface on 3 September 2006, at 07:41 CEST (05:41 UT). However, it is also possible that the small satellite hits the Moon on the previous orbit at 02:37 CEST (00:37 UT).
The time of impact has been determined by orbit predictions following the major thruster manoeuvres performed from 23 June to 2 July 2006 (plus a few trajectory correction manoeuvres performed on 27 and 28 July 2006) – aimed at changing the impact site from the lunar far-side to the lunar near-side, taking into account the Sun-Earth-Moon gravity perturbations. These make the SMART-1 orbit perilune (point of closest approach to the lunar surface) naturally drift down about one kilometre per orbit.
In determining the impact orbit, ESA's spacecraft control experts are also taking into account the tiny perturbations to the trajectory induced by the small hydrazine thrusters to offload the spacecraft reaction wheels, and some slight additional gravity perturbations. An additional slot is also available for a corrective manoeuvre on 1 and 2 September 2006 if needed, to maintain the impact time as planned and allow ground based observations.
There remains, however, an uncertainty on the time of impact, because the lunar topography is still not completely known. The best lunar topographic maps currently available are based on data from the US Clementine mission in 1994. The laser altimeter experiment (LIDAR) on board provided the spacecraft altitude over a grid of roughly every kilometre. The values in between have been interpolated by the SMART-1 experts, assuming that there are no unknown peaks in those areas.
However, there is still a chance that an unknown peak is just in SMART-1's way as the spacecraft spirals down to the surface. This means that, if encountering terrain about one kilometre high, SMART-1 may hit ground at 02:37 CEST (00:37 UT), at which time the spacecraft will be flying at about 800 metres altitude. This would result in an impact one orbit earlier than the estimated 07:41 CEST (05:41 UT) impact on 3 September. For the same reason, there is even a possibility that impact could happen on 2 September, at 21:33 CEST (19:33 UT).
So, for SMART-1, the last lunar approach orbits will be rather like low-altitude flying with incomplete terrain maps. Results from SMART-1 and the next fleet of lunar orbiters may help to improve maps for future lunar exploration.
Impact visibility for ground observers
"Dependent on the impact times, different parts of the world will have the best seats for the final impact show , some seats in sunlight and others at night", says Bernard Foing, ESA SMART-1 Project Scientist.
If the impact occurs nominally on 3 September 2006 at 07:41 CEST (05:41 UT), observers from North and South America and the East Pacific will be able to see the impact or 'listen' to it through radio telescopes during night time, with best views from America's East coasts as well as from Hawaii and the East Pacific.
If the probe impacts on 3 September at 02:36 CEST (00:36 UT), the impact will be easily visible from South America, Canary Islands (Spain) and the US East coast, and from radio observatories from the US in daylight.
Should the impact occur on 2 September 2006 at 21:33 CEST (19:33 UT), two orbits before the nominal one, then Africa and South Europe would have a clear view just after sunset. Radio observatories from South America can listen to SMART-1's final signal in daylight.
For more information on the ground observations follow this link to find more information about SMART-1 impact site observations.
Bernard Foing | alfa
One-way roads for spin currents
23.05.2018 | Singapore University of Technology and Design
Tunable diamond string may hold key to quantum memory
23.05.2018 | Harvard John A. Paulson School of Engineering and Applied Sciences
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
23.05.2018 | Life Sciences
23.05.2018 | Life Sciences
23.05.2018 | Physics and Astronomy