Russian rocket takes off to resupply ISS after 2 previous missions failed
(CNN)Resupply missions to the International Space Station rarely fail -- let alone twice in row, like the last two did.
That may make the arrival of the Russian cargo spacecraft that launched Friday all the more welcome -- even if the ISS does keep a large backlog of supplies on board.
The crewless ProgressM-28M lifted from the Baikonur Cosmodrome in Kazakhstan just before 8:00 a.m. local time (12:00 a.m. ET / 5:00 a.m. GMT) and cut a clean path through a clear blue sky en route to a low-Earth orbit.
Minutes later, the Soyuz-U cargo vehicle successfully separated from the rest of the rocket, according to the Russian Federal Space Agency, also called Roscosmos.
And it was on course to deliver 5,249 pounds (2,381 kilograms) of supplies to the ISS on Sunday. They include food, water, oxygen, fuel and scientific apparatuses.
Missions like this are fairly routine, but three spacecraft bound for the ISS with tons of supplies have been lost since last October -- including the two most recent.
This past Sunday, one blew to pieces shortly after liftoff.
The SpaceX Falcon9 rocket was boosting a Dragon supply capsule stocked with a spacesuit, water filtration equipment, food, water, and experiments submitted by students. It also carried a docking adapter which was to allow people to arrive aboard America's first crewed spacecraft since the space shuttle.
All was lost.
On April 28, the last Russian rocket that launched on a resupply mission went out of control and ended up in an orbit incompatible with that of the ISS. It eventually burned up in Earth's atmosphere along with clothing, spacewalk hardware, propellant, oxygen, water, spare parts, supplies and experiments.
And in October 2014, a rocket on a resupply mission had to be detonated, when its launch went awry right after liftoff. The Antares, made by the Orbital Space Sciences Corporation, was carrying provisions, experiments and equipment.
"We've always assumed we would lose a vehicle every so often," said Michael Suffredini, manager of the International Space Station Program for NASA. "Having three this close together is not what we'd hoped for."
But the ISS was prepared. Even after the SpaceX Falcon9 exploded on Sunday, it had enough supplies to last the crew until October, at least.
Life on the ISS
The station orbits about 248 miles (400 kilometers) above Earth. It circles the planet every 90 minutes.
NASA says more than 200 people from 15 countries have visited it since November 2000.
The ISS measures 357 feet end-to-end and has more space than a six-bedroom house.
What do the astronauts do up there? Mostly, they conduct experiments. But they also exercise to offset the effects of near-zero gravity.
If you want to see it with your own eyes, NASA can tell you when it will be flying right over your hometown. It looks like a high-flying airplane tracing a beeline across the sky.
CNN's Radina Gigova contributed to this report.