MOST (spacecraft)

Microvariability and Oscillations of Stars

Names	MOST
Mission type	Astronomy
Operator	CSA
COSPAR ID	2003-031D
SATCAT no.	27843
Website	MOST home page
Spacecraft properties
Launch mass	53 kg (117 lb)
Dimensions	66 cm × 20 cm (26.0 in × 7.9 in)
Power	35 W
Start of mission
Launch date	14:15, June 30, 2003 (2003-06-30T14:15)
Rocket	Rockot/Breeze-KM
Launch site	Plesetsk 133/3
Contractor	Eurockot
Orbital parameters
Reference system	Geocentric
Regime	Polar
Semi-major axis	7,203 km (4,476 mi)
Eccentricity	0.0010821
Perigee altitude	824.7 km (512.4 mi)
Apogee altitude	840.3 km (522.1 mi)
Inclination	98.7157 degrees
Period	101.4 minutes
RAAN	126.1054 degrees
Argument of perigee	129.3968 degrees
Mean anomaly	230.8168 degrees
Mean motion	14.20521415 rev/day
Epoch	27 April 2016, 11:16:58 UTC
Revolution no.	66487
Main telescope
Type	Maksutov catadioptric
Diameter	15 cm (5.9 in)
Focal length	88.2 cm (34.7 in)
Wavelengths	350-750 nm (Visible light)

The Microvariability and Oscillations of Stars telescope, better known simply as MOST, is 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). MOST is the first spacecraft dedicated to the study of asteroseismology, 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 is to monitor variations in star light, which it does 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 53 kg (117 pounds) 65 cm (26 in) wide and tall and 30 cm (12 in) deep, it is the size and weight of a small chest or an extra-large suitcase filled with electronics. This places it in the microsatellite category.

MOST was developed as a joint effort of the Canadian Space Agency, Dynacon Enterprises Limited (now Microsatellite Systems Canada Inc), the Space Flight Laboratory (SFL) at the University of Toronto Institute for Aerospace Studies, and the University of British Columbia. Led by Principal Investigator Jaymie Matthews, the MOST science team's plan is to use observations from MOST to use asteroseismology to help date the age of the universe, and to search for visible-light signatures from extrasolar planets.

MOST features an instrument comprising a visible-light dual-CCD camera, fed by a 15-cm aperture Maksutov telescope. One CCD gathers science images, while the other provides images used by star-tracking software that, along with a set of four reaction wheels (computer-controlled motorized flywheels that are similar to gyroscopes) maintain 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 in the UK); 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) is less than $10 million in Canadian funds (about 7 million Euros or 6 million USD, at exchange rates at time of launch).

Development of the satellite was managed by the Canadian Space Agency's Space Science Branch, and was funded under its Small Payloads Program; its operations are currently (as of 2012) managed by the CSA's Space Exploration Branch. It is 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 is 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."

Current Operations

In October 2014, the MOST Satellite was acquired by Microsatellite Systems Canada Inc. (MSCI), who has operated the satellite since launch in 2003. MSCI engineers have monitored the satellite's health over the years and have performed numerous upgrades to the software. MSCI has commenced commercial operation of the satellite and offers 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. MSCI is also the prime contractor for the NEOSSat spacecraft.

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. In 2006 observations revealed a previously unknown class of variable stars, the "slowly pulsating B supergiants" (SPBsg). In 2011, MOST detected transits by exoplanet 55 Cancri e 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. Further reports of discoveries are listed on the MOST science page at the University of British Columbia.

MOST Target Campaigns

• Procyon
• HD 209458 b
• HD 163899 (guide star)
• 55 Cancri e
• HIP 116454 b

See also

• Asteroseismology
• Extrasolar planet

External links

• MOST: Canada's First Space Telescope
• Microsat Systems Canada Inc. - MOST
• UTIAS Space Flight Laboratory
• Canadian Space Agency - MOST