An electrical fault aboard the International Space Station (ISS) forced NASA to postpone the launch of the SpaceX CRS-17 Cargo Dragon from May 1 to May 3, giving the station crew more time to fix the issues.
A new Falcon 9 Block 5 booster was commissioned to launch the spacecraft and completed a static fire test on SpaceX's LC-40 block on 27 April. The Cargo Dragon capsule, however, completed its first orbital refueling mission (CRS-12) in September 2017 and has since been reshaped for a second launch. After the CRS-17, three launches remain in SpaceX's NASA CRS1 contract between now and early 2020, after which Dragon 2 (ie Crew Dragon) must take over. However, a recent flaw during a Crew Dragon test put those plans into question.
17th Dragon of Charge mission
Known as C113, the CRS-12 capsule is the latest Dragon 1 manufactured by SpaceX, leaving a fleet of five in-flight proven spacecraft to SpaceX to complete the remaining eight ISS refueling missions under its Commercial Resupply Services 1 (CRS1) . The CRS-17 is the last installment of SpaceX's ISS refueling saga and manifests itself with ~ 2,500 kg (5500 lb) of cargo.
Along the ride are NASA's Orbiting Carbon Observatory-3 (OCO-3) and the multi-experiment STP-H6 investigation, two large pieces of hardware that will be delivered to ISS on Dragon's non-pressurized trunk. After being anchored in the ISS, the astronauts will unpack dozens of packages stored inside Cargo Dragon's cabin. Some time later, the station's Canadarm2 will be used to pick up the OCO-3 and the STP-H6 and install each on the outer space station, where we hope to live long and scientifically fruitful lives.
SpaceX and NASA have designated a new Falcon 9 Block 5 booster – probably the B1056 – to launch the CRS-17. To preserve the scene of the April 20 explosion of the Crew Dragon C201, the rocket will attempt to land some 20 miles off the coast aboard drone Ship Of I Still Love You (OCISLY). Originally scheduled for April 25, CRS-17 was postponed to 26, 30, 1, and 3 May, most of them being requested by NASA for scheduling ISS.
The last delay – from May 1 to no earlier than (NET) on May 3 – was triggered by an unexpected electrical fault aboard the ISS, cutting off the redundancy of its two-sequence Canadian (2-SSRMS) control systems for an. In other words, Canadarm2 – used to "grab" and dock spacecraft like Cargo Dragon and Cygnus for the station – is now just an electrical failure to become inoperable. The CRS-17 will remain grounded until two-string redundancy (ie single fault) is returned to Canadarm2 and additional impacted systems.
In the event that the ISS astronauts and NASA ground control are able to repair the electrical systems in a timely manner, the CRS-17 is scheduled to be launched at 3:11 am (3h11 am) on May 3.
In the shadow of the crew dragon
A recent catastrophic failure of Crew Dragon raises serious doubts about SpaceX's CRS2 contract, but the nominal plan involves retiring Dragon 1 after the CRS-20 and flying all future cargo missions with the Crew spacecraft Dragon In the case of Crew Dragon C201 failure likely to delay SpaceX's CRS2 schedule for several months, there are contingency plans to continue flying in a remodeled Dragon 1 spacecraft.
However, each Dragon 1 has been designed for a maximum of three orbital missions, which means that SpaceX's current fleet of capsules can withstand no more than six additional refueling missions before they reach their end of life. SpaceX thus has two potential capturing missions – CRS-21 and CRS-22 – that could theoretically represent up to a year of delays in Dragon 2. In addition, additional delays in Dragon 2 could create a gap where NASA would have to provide ISS without the services of SpaceX.
At best, SpaceX and NASA will quickly find an unequivocal culprit in the catastrophic C201 explosion, mend the technical and organizational flaws that have allowed that to happen, and stand in the blink of an eye. In fact, it is likely that the failure delays the future Crew Dragon (and therefore Dragon 2) with a minimum of 6-12 months. SpaceX will likely need to change the launch order of its capsules by reassigning DM-2's Crew Dragon to the US Crew-1 Vehicle (USCV-1) Abortion-in-Flight Test (IFA) and Crew Dragon to SpaceX's first crewed demonstration mission (DM-2). After such a fatal and potentially fatal flaw, it is even possible that NASA needs an additional orbital launch without debris before allowing SpaceX to pilot astronauts into the Crew Dragon.
Since SpaceX's nominal CRS2 plan involved the slight modification and reuse of Dragon 2s after manned missions, the future (and timeline) of the company's Cargo and Crew contracts are closely intertwined. With any luck, SpaceX and NASA will be able to solve the technical, organizational and logistical problems they are facing and ensure a stable future for Dragon 2. Meanwhile, Cargo Dragon's CRS-17 mission offers SpaceX the chance to partially verify The Cargo Dragon C201 issues are relegated only to Dragon 2 and Dragon 2.
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