The US space shuttle has made its final night launch from the Kennedy Space Center in Florida.
The Endeavour orbiter soared into the Florida sky on a 13-day mission to the International Space Station (ISS).
It is delivering a connecting node and a large window module in what will be one of the last ISS assembly flights.
The US space agency (Nasa) plans just four further shuttle missions after this one - and all of them are planned to launch in daylight hours.
The blast-off occurred at 0414 local time (0914 GMT), 24 hours behind schedule. Endeavour should have left Earth on Sunday but was held on the pad because of a thick layer of cloud blanketing Florida's Space Coast.
Monday's weather was much more obliging, and the shuttle's ascent to orbit made for quite a spectacle.
"I saw it very clearly through solid rocket booster separation, and then it disappeared behind some clouds and I got kinda disappointed. But then it broke out of those clouds and that's when I was able to see it all the way out to seven minutes in flight. For the last night launch, it treated us well."
Endeavour's mission is an important moment for the European Space Agency's (Esa) contribution to the station project. Both the new modules were manufactured in Italy by Thales Alenia Space.
Node 3, also known as Tranquility, will house the station's core life-support systems.
It will also store a treadmill the crew must use regularly to exercise their bodies and maintain bone density.
One of the risks of living in microgravity conditions is that bones tend to lose strength over time.
The Cupola is an observation tower that will be used to control robots working on the exterior of the platform.
It is constructed in the shape of a dome, with six trapezoidal side windows and a circular top window of a little under 80cm, making it the largest window ever built for space.
The Cupola is travelling into orbit attached to the end cone of Node 3 but once in orbit will be transferred to a berthing point that looks straight down to Earth.
The spectacular views from the Cupola mean it is likely to become a popular place on the station for astronauts to relax.
Esa's project manager on Node 3 and the Cupola, Philippe Deloo, told the BBC: "I heard that on orbit the most favourite past-time of the crew when they're off duty is to watch out the window and look at Earth.
"The psychological effect of being able to look outside, to look at the Mother Earth, is something that has long been put forward as an argument to have windows on the station."
Endeavour's crew is commanded by George Zamka, a colonel in the US Marine Corps, and includes the British-born mission specialist Nicholas Patrick.
Dr Patrick will conduct the three spacewalks to install the two modules with colleague Bob Behnken.