The Microvariability and Oscillations of Stars/Microvariabilité et Oscillations STellaire (MOST), was Canada's first space telescope. Up until nearly 10 years after its launch it was also the smallest space telescope in orbit (for which its creators nicknamed it the "Humble Space Telescope", in reference to one of the largest, the

Hubble The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versa ...

). MOST was the first spacecraft dedicated to the study of

asteroseismology Asteroseismology or astroseismology is the study of oscillations in stars. Stars have many resonant modes and frequencies, and the path of sound waves passing through a star depends on the speed of sound, which in turn depends on local temperature ...

, subsequently followed by the now-completed CoRoT and Kepler missions. It was also the first Canadian science satellite launched since ISIS II, 32 years previously.

Description

As its name suggests, its primary mission was to monitor variations in star light, which it did by observing a single target for a long period of time (up to 60 days). Typically, larger space telescopes cannot afford to remain focused on a single target for so long due to the demand for their resources. At , wide and tall, and deep, it was the size and weight of a small chest or an extra-large suitcase filled with electronics. This places it in the

microsatellite A microsatellite is a tract of repetitive DNA in which certain DNA motifs (ranging in length from one to six or more base pairs) are repeated, typically 5–50 times. Microsatellites occur at thousands of locations within an organism's genome. ...

category. MOST was developed as a joint effort of the

Canadian Space Agency The Canadian Space Agency (CSA; french: Agence spatiale canadienne, ASC) is the national space agency of Canada, established in 1990 by the ''Canadian Space Agency Act''. The president is Lisa Campbell, who took the position on September 3, 2020 ...

, Dynacon Enterprises Limited (now Microsatellite Systems Canada Inc), the Space Flight Laboratory (SFL) at the

University of Toronto Institute for Aerospace Studies A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, the ...

, and the University of British Columbia. Led by Principal Investigator Jaymie Matthews, the MOST science team's plan was to use observations from MOST to use

to help date the age of the universe, and to search for visible-light signatures from extrasolar planets. MOST featured an instrument comprising a visible-light dual- CCD camera, fed by a 15-cm aperture Maksutov telescope. One CCD gathered science images, while the other provided images used by star-tracking software that, along with a set of four reaction wheels (computer-controlled motorized flywheels that are similar to

gyroscope A gyroscope (from Ancient Greek γῦρος ''gŷros'', "round" and σκοπέω ''skopéō'', "to look") is a device used for measuring or maintaining orientation and angular velocity. It is a spinning wheel or disc in which the axis of rota ...

s) maintained pointing with an error of less than 1 arc-second, better pointing by far than any other microsatellite to date. The design of the rest of MOST was inspired by and based on microsatellite bus designs pioneered by AMSAT, and first brought to commercial viability by the microsatellite company SSTL (based at the

University of Surrey The University of Surrey is a public research university in Guildford, Surrey, England. The university received its royal charter in 1966, along with a number of other institutions following recommendations in the Robbins Report. The institut ...

in the United Kingdom); during the early stages of MOST development, the core group of AMSAT microsatellite satellite designers advised and mentored the MOST satellite design team, via a know-how transfer arrangement with UTIAS. This approach to satellite design is notable for making use of commercial-grade electronics, along with a "small team," "early prototyping" engineering development approach rather different from that used in most other space-engineering programs, to achieve relatively very low costs: MOST's life-cycle cost (design, build, launch and operate) was less than $10 million in Canadian funds (about 7 million Euros or 6 million USD, at exchange rates at time of launch).

Operation history

Development of the satellite was managed by the

's Space Science Branch, and was funded under its Small Payloads Program; its operations were (as of 2012) managed by the CSA's Space Exploration Branch. It was operated by SFL (where the primary MOST ground station is located) jointly with Microsat Systems Canada Inc. (since the sale of Dynacon's space division to MSCI in 2008). As of ten years after launch, despite failures of two of its components (one of the four reaction wheels and one of the two CCD driver boards), the satellite was still operating well, as a result of both on-going on-board software upgrades as well as built-in hardware redundancy, allowing improvements to performance and to reconfigure around failed hardware units. In 2008, the MOST Satellite Project Team won the Canadian Aeronautics and Space Institute's Alouette Award, which recognizes outstanding contributions to advancement in Canadian space technology, applications, science or engineering.

Termination of operations funding by CSA

On 30 April 2014, the Canadian Space Agency announced that funding to continue operating MOST would be withdrawn as of 9 September 2014, apparently as a result of funding cuts to the Canadian Space Agency's budget by the Harper government, despite the fact that the satellite continues to be fully operational and capable of making on-going science observations. P.I. Jaymie Matthews responded by saying that "he will consider all options to keep the satellite in orbit, and that includes a direct appeal to the public."

Post-CSA-funded operations

In October 2014, the MOST Satellite was acquired by MSCI, which then commenced commercial operation of the satellite, offering a variety of potential uses including continuing the original MOST mission in partnership with Dr. Matthews, but also other planetary studies, attitude control system algorithm R&D, and Earth observation. MOST was finally decommissioned in March 2019, after an apparent failure of its power subsystem.

Discoveries

The MOST team has reported a number of discoveries. In 2004 they reported that the star Procyon does not oscillate to the extent that had been expected, although this has been

disputed Controversy is a state of prolonged public dispute or debate, usually concerning a matter of conflicting opinion or point of view. The word was coined from the Latin ''controversia'', as a composite of ''controversus'' – "turned in an opposite d ...

. In 2006 observations revealed a previously unknown class of variable stars, the "slowly pulsating B supergiants" (''SPBsg''). In 2011, MOST detected transits by

exoplanet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...

55 Cancri e 55 Cancri e (abbreviated 55 Cnc e, formally named Janssen and nicknamed "Hell on Earth") is an exoplanet in the orbit of its Sun-like host star 55 Cancri A. The mass of the exoplanet is about 8.63 Earth masses and its diameter is about twice ...

of its primary star, based on two weeks of nearly continuous photometric monitoring, confirming an earlier detection of this planet, and allowing investigations into the planet's composition. In 2019, MOST photometry was used to disprove claims of permanent starspots on the surface of that were alleged to be caused by interactions between the

magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to ...

s of the star and its "hot Jupiter" exoplanet.

MOST target campaigns

* Procyon * HD 209458 b * HD 163899 (guide star) *

* HIP 116454 b

References

External links

MOST website
by the Canadian Space Agency
MOST website
by the University of British Columbia
MOST website
by the University of Toronto

by Microsat Systems Canada Inc. {{DEFAULTSORT:Most (satellite) 2003 in Canada Derelict satellites orbiting Earth Exoplanet search projects Optical telescopes Satellites of Canada Space telescopes Spacecraft launched by Rokot rockets Spacecraft launched in 2003