The SpaceX team have already conducted three successful launches in 2015, kicked off by the CRS-5/SpX-5 Dragon mission to the ISS in January.
The Dragon concluded her mission with a splashdown finale in the Pacific Ocean the following month, just a few days prior to SpaceX’s next launch – with the successful lofting of the DSCOVR spacecraft.
Less than three weeks passed before SpaceX completed a hat-trick of launches in 2015, as another Falcon 9 v1.1 launched the rocket’s first dual passenger mission, lofting the ABS-3A and Eutelsat 115 West B satellites into orbit.
A fourth Falcon 9 mission was penciled in for late March, with SpaceX tasked with launching Turkmenistan’s TurkmenAlem52E/MonacoSat 1 (TurkmenSat 1) communications satellite.
However, an issue spotted ahead of the Static Fire test, specific to the helium pressurization system’s bottles (COPVs), resulted in a change to the planned manifest.
With SpaceX currently launching both commercial satellites and NASA cargo resupply missions, schedule considerations are naturally favored towards the latter.
This mainly relates to the busy Visiting Vehicle schedule of the International Space Station, with numerous constraints resulting in short windows of opportunity for when a Dragon can set sail for the orbital outpost.
As such, SpaceX – in agreement with NASA – opted to ensure the CRS-6 Dragon would be in a position to launch to the ISS within an available slot in April.
While returning the core tothe Autonomous Spaceport Drone Ship (ASDS) isn’t a primary mission objective, a successful touchdown on deck will provide a major advance inSpaceX’s reusability aspirations.
Aided by the experiences of previous return attempts, the first stage’s Merlin 1D engines, control thrusters, grid fins and landing legs will all be working together toward the goal of not only a smooth ASDS landing, but also the prospect of a life extension.
A success will result in both a triumphant return to port and a trip to Spaceport America in New Mexico for additional testing.
The initial launch CRS-6 date of April 10 has since slipped slightly to April 13 (4:33 pm EDT) – with each opportunity somewhat constrained by the orbital requirement of an instantaneous launch window. A Static Fire test has been scheduled for April 10.
In the event the launch date holds, this latest Dragon spacecraft – carrying 4,300 pounds of supplies and payload – will arrive at the ISS on April 15, prior to being grabbed by the Station’s robotic arm under the control of Expedition 43 Flight Engineer Samantha Cristoforetti.
The spacecraft will return to Earth around five weeks later, by which time SpaceX will hope to have launched its fifth mission of the year.
Providing the CRS-6 mission is launched without any major issues or delays, SpaceX may be in a position to hold its next launch opportunity – involving the TurkmenSat 1 mission – to what is currently scheduled for April 24.
As with the mission, the Falcon 9 v1.1 won’t have enough spare propellant to conduct a first stage landing attempt on the ASDS, thus the stage is without grid fins and landing legs.
As previously mentioned, this mission was set to launch in March, prior to the discovery of “bad trends” in the data relating to the helium tanks (bottles) used on the Falcon 9.
It is not fully understood if the data related to routine helium system testing or a fault in the hardware of the actual Falcon 9 tasked with the TurkmenSat-1 launch. However, the issue is now classed as resolved.
Following the launch of TurkmenSat-1, SpaceX engineers will conduct their usual post launch clean up of the SLC-40 pad, prior to switching gears to conduct test program objectives for Dragon 2, part of NASA’s Commercial Crew aspirations.
Based on the latest L2 schedule information, this test is currently targetting May 2, although this target is subject to change due to the two launches that are planned to take place ahead of the test.
The vehicle itself is in a stage of processing that will see it ready for the test by mid-April.
Additional information notes the abort vehicle has been outfitted with seven seats, one of which is already occupied by a human-size test dummy, embedded with a suite of sensors.
The pressure vessel is based on the cargo Dragon vehicle, albeit with the smaller hatch. There are no actual windows in the capsule, with gold mirrors mimicking the outer windows of the operational Dragon 2.
The Trunk is a composite structure with cork insulation, with the exterior painted white.
Following the Pad Abort test, preparations will take place to launch the next cargo Dragon on the CRS-7/SpX-7 mission to the ISS. Also on the books are missions that include Orbcomm OG2 and Jason-3.
SpaceX is also looking to conduct another Commercial Crew objective for Dragon 2, with the Ascent Abort test currently showing July 1 as the earliest possible test date.
However, that date is likely to move to the right over the coming weeks, based on natural movement in the company’s busy launch schedule.
Otherwise known as the “In Flight Abort test”, the objectives will utilize a Dragon 2 test vehicle on a Falcon 9 out of Vandenberg, providing a real life test of an abort scenario occurring at “Max Drag” in the transonic region.