April 4 saw two orbital missions, one space probe milestone, and a rocket ground test.
The Progress MS-11 resupply mission reached the International Space Station at 1422 UT, following two orbits and a launch from Baikonur on a Soyuz-2 rocket at 1101. The capsule delivered 3.4 t of spare parts, fuel, and consumables. The successful mission is another sign that life is returning to normal on the station, which returned to a full crew of six astronauts after Soyuz MS-12 arrived three weeks ago.
At 1704, Arianespace launched four commsats for SES/o3b on Soyuz mission VS22. Much like the existing o3b fleet, the new satellites will operate at a 8000-km medium-earth orbit, and provide high-speed internet through targetable spot-beams. Though other firms are building low-earth orbit Internet constellations, for the moment o3b is the highest-performance option among systems that are fully operational. It is also relatively expensive and mainly filling an enterprise backhaul role for ISPs and wireless providers, rather than a direct-to-consumer model.
Also in space, the Parker Solar Probe reached its second perihelion at about 2230 UT. Flight controllers at Johns Hopkins University Applied Physics Laboratory (JHUAPL) confirmed that the probe was fully operational during the 24.8 gigameter flyby. This is an important moment as the closest sensor platform ever to approach the Sun continues its studies.
Northrop Grumman performed a static fire of a GEM63 motor in Utah on Thursday. The graphite-epoxy motor is filled with solid rocket fuel and is 1.6 meters in diameter (63 inches). The GEM series of boosters has been in service since 1990, and has been gradually widened and lengthened. GEMs are used by ULA rockets – such as the Atlas V, Delta IV, and the upcoming Vulcan.