Look! Up in the sky! Five Brit satellites on one Indian rocket!

The UK is entrusting a bunch of earth observation satellites to India's burgeoning space program.

Three DMC3 optical observation satellites, along with a couple of other payloads, will be hoisted on July 10 by India's Polar Satellite Launch Vehicle (PSLV).

It's the thirtieth mission for the PSLV, and also the heaviest. The DMC3 satellites each weigh 447 kg, and with the other two satellites (CBNT-1 and De-OrbitSail), the total 1,440 kg is also the largest commercial mission undertaken by the Indian Space Research Organisation (ISRO) and its commercial arm Antrix.

The DMC3 constellation will be hoisted into a sun-synchronous orbit at 647 km altitude, giving them daily revisit times suitable for disaster monitoring and change detection, with the best chance of cloud-free images.

The constellation is based on Surrey Satellite Technology's SSTL-300S1 platform, which will deliver 1m resolution, and the ability to carry out terrain mapping, strip imaging and mosaic imaging. Chinese company 21AT is leasing all of the £100 million constellation's imaging capacity.

The 120° separation between the members of the constellation means they'll image “any target on the Earth's surface” at least once a day.

At 3m tall, ISRO says it was a challenge to fit the satellites in the existing PLSV payload fairing, with various adapters needed.

One of the DMC3 satellites during assembly at Surrey Satellite Technologies

The other two payloads are experimental: the CBNT-1 micro-satellite, an Earth observation demonstrator; and DeOrbitSail, a 3U CubeSat for testing a deployable sail for rapid de-orbiting. The experimental payloads also came from Surrey Satellite. ®