There were two launches today in a busy month of rocket lifts. First off, around midnight GMT or yesterday evening if one is in America, China launched the DArk Matter Particle Explorer (DAMPE) aboard a Long March 2D from Jiuquan Space Center. DAMPE is China’s first dedicated astrophysics observatory spacecraft, but will not be the last as China plans a series of astrophysics spacecraft. The probe will orbit the Earth and is equipped to detect gamma rays, electrons, and high energy particles in hopes of finding more clues about the nature of dark matter, and the team particularly hopes to detect annhilation events, when two opposing subatomic particles collide and annhilate one another. The data set will be invaluable to scientists around the world in pursuit of the elusive traces of dark matter.
The second flight for the day came out of Kourou, French Guiana: a Soyuz rocket bearing aloft the latest pair of Galileo spacecraft for Europe’s nascent satellite navigation system, a competitor to GPS, GLONASS, and Beidou.
Note the curious hybrid launch complex at Kourou. The Soyuz pad is nearly identical to those at Baikonur and Plesetsk, since they must service the same rocket, but there is also a vertical assembly building. Soyuz is integrated horizontally and then erected on the pad, so what is the vertical assembly building for?
It solves a problem. Soyuz was built as an ICBM first of all, and it had to be able to be fully integrated and ready to go inside a shed until called upon, and then hauled out to the pad by a train and erected hours before launch. Thus, Russia is in the habit of integrating its payloads to the rocket in the horizontal assembly building as well. But Europe is not. Its satellites are not designed to be sitting on their sides for a prolonged period. So a compromise was reached. The rocket is assembled on its side, as Soyuz always is, but then is towed to the pad and erected without a payload. Then the assembly building is pulled into place over the rocket and the payload is added on top. Once checks are complete, the building can be rolled back and launch preparations can proceed as normal.
Thus, Kourou is the only place in the world where a headless Soyuz can roll around!