Diwata-1

Did You Know?

• The PHL-Microsat program aimed to boost progress on the creation of the Philippine Space Agency.
• The University of the Philippines Diliman campus allocated an area for a space research laboratory for continued microsatellite technology development.
• The facility for the space research laboratory was funded by the PCIEERD of DOST.

Background

A Japanese-led project aims to launch 50 microsatellites by 2050 to capture images after natural disasters, working with partners in several Asian nations, including the Philippines. The first satellite from this effort for the Philippines was Diwata-1, built under the Philippine Scientific Earth Observation Microsatellite (PHL-Microsat) Program. This three-year program, funded by the Department of Science and Technology (DOST), began in December 2014 and involved the University of the Philippines, DOST-ASTI, and Japan's Tohoku and Hokkaido universities.

Diwata-1 was an upgraded version of Japan's Raijin-2 satellite. Commands were sent to Diwata-1 and images were received at the Philippine Earth Data Resources Observation Center (PEDRO) ground station, where local teams also processed the data. Before Diwata-1, the Philippines had two earlier satellites, Agila-1 and Agila-2, but both were owned by non-Philippine or private firms. The PHL-Microsat program was created after the government paid for foreign satellite imagery following Typhoon Haiyan in 2013, an expense that Carlos Primo David of PCIEERD described as a "small investment" compared to the cost of buying such data.

Development

A team of nine Filipino engineers from the DOST-Advanced Science and Technology Institute and the University of the Philippines, called the "Magnificent 9", produced Diwata-1 in collaboration with scientists and engineers from the two Japanese universities. They were sent to Japan in October 2015, and assembly and testing were completed in December 2015. The satellite was handed over to JAXA on January 13, 2016, at the Tsukuba Space Center, and JAXA sent it to NASA on January 18, 2016, after final tests. Component tests, vibration tests, electrical tests, off-gas test, fit checking, and continuous functionality tests of modules and sensors were conducted, along with software optimization.

Instruments

Diwata-1 carried three scientific instruments: the High Precision Telescope (HPT), the Space-borne Multispectral Imager (SMI) with Liquid Crystal Tunable Filter (LCTF), and the Wide Field Camera (WFC). It also had one engineering control instrument, the Middle Field Camera (MFC). The HPT had a ground sample distance (GSD) of 3 m at 400 km and was studied for monitoring damage from natural disasters; it was equipped with four CCDs for red, blue, green, and near infrared light.

The SMI with LCTF had a GSD of 80 m at 400 km and was studied for measuring vegetation changes and phytoplankton biomass, with two CCDs for visible and near infrared regions at 13 nm intervals. The WFC had a GSD of 7 km and a panchromatic CCD with a field view of 1800 × 1340, used for large-scale cloud patterns and weather disturbances. The MFC, with a colored CCD and expected GSD of 185 m, calibrated the attitude determination algorithm and aided in locating images from the HPT and SMI.

Launch and mission

Diwata-1 launched on March 23, 2016, from Cape Canaveral, Florida, as a payload of Orbital ATK's Cygnus spacecraft on an Atlas V rocket as part of a supply mission to the ISS. The initial plan had been to launch via a SpaceX vehicle. An orbital slot was secured from JAXA. Cygnus reached the ISS on March 26, and cargo was unloaded over two weeks.

The satellite was deployed from the Kibo module using the JEM Small Satellite Orbital Deployer (J-SSOD), marking the first deployment of a 50-kg class microsatellite from that module. Deployment was scheduled for April 20 or 21, 2016, after a DOST request to JAXA for deployment between March 21 and April 30 when the ISS was at its highest altitude. It was later announced for April 27 at 7:00 p.m. PST, with actual deployment at 7:45 p.m. PST, involving British astronaut Tim Peake.

The Philippine and Japanese flags were raised at the Tsukuba Space Center. The mission was expected to last around 20 months. The engineering team at Tohoku University received the first communication hours after deployment. The PEDRO ground station in the Philippines had primary control via UHF band, receiving telemetry via UHF and images via X-band; the Tohoku University Ground station (CRESST) also had access.