In the last couple of days something of a watershed moment in spaceflight has occurred – the first successful resupply of the ISS by a commercial space vehicle instead of one launched by a government agency. Space X are truly breaking new ground.
After a couple of postponements, last Sunday night saw a fantastic nighttime launch from Cape Canaveral, launching the first of at least 12 ISS cargo resupply missions that NASA has contracted to commercial spaceflight corporation Space X. The rocket also carried a secondary payload in the form of an Orbcomm communications satellite that was to be released after the Dragon resupply capsule had been released.
The launch wasnt without incident as at around T+1.19 one of the nine Merlin engines onboard the Dragon rocket shut down automatically, resulting in the engine fairing being shattered by a pressure release. Contrary to early speculation, the engine did NOT explode as engineers continued to receive telemetry from the engine. To compensate for this, the first stage burnt for about 30 seconds longer to reach its primary objective of deploying the Dragon resupply capsule but missed the window for the second stage burn to place the Orbcomm satellite into the correct orbit as to do so would be risking collision with the ISS after the second stage ceased its burn.
The satellite was released with initial hopes of using its onboard thrusters to boost itself into a higher orbit but it eventually burnt up in reentry. Orbcomm is reportedly claiming its insurance for the lost vehicle.
The mission wasnt a total loss, though – Orbcomm’s satellite is something of a prototype and the limited time aloft allowed for some quick testing of new technology.
Docking with the ISS
Dragon docked with the ISS only a day after it was launched, 24 hours ahead of schedule. Apparently the crew of the ISS just couldn’t wait to get their hands on a tub of chocolate ripple ice cream that was included with the rest of the cargo.
The ice cream was sent in a freezer that will be used for storing scientific samples at a temperature of -160 degrees celsius (slightly overkill). Also among the cargo are 23 microgravity experiments designed by participants of the Student Spaceflight Experiment Program and the Micro-6 experiment designed to look at how to better manage infections in space.
When Dragon returns it will carry a lot of these same experiments back, plus a lot of sundry equipment.
This mission is a significant milestone in spaceflight as it is the first time a private company has been contracted by a government space agency to provide significant maintenance services in space that had previously been carried out by the agency’s own craft. There appears to be a high level of confidence in Space X despite the engine shutdown and missed orbit of the Orbcomm secondary payload satellite – Orbcomm themselves are still contracting Space X to carry other satellites of the same kind into space. What Space X need to do now is to build on their technical innovation and iron out the problems in the Merlin engine that caused it to shut down.
All in all, a promising start.
NASA Press Release on launch of Dragon.
NASA Press Release on successful docking with ISS